8551
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Flanagan JR, Pittet D, Li N, Thievent B, Suter PM, Wenzel RP. Predicting survival of patients with sepsis by use of regression and neural network models. Clin Perform Qual Health Care 1996; 4:96-103. [PMID: 10156949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
OBJECTIVES (1) To predict at the time of diagnosis of sepsis the subsequent occurrence of multiple organ failure and patient death; and (2) to compare the prediction accuracies of standard multiple logistic regression (MLR) and neural network (NN) models. METHODS The data were collected during a 5-year period for all patients (n=173) who met prospectively determined criteria for sepsis and had positive blood culture results while admitted in the surgical intensive care unit at the University Hospital of Geneva, Switzerland. These data formed the basis for a retrospective cohort study described elsewhere. The MLR model was adapted from existing data. An NN model of the feed-forward, back-propagation type was constructed for predicting the outcome of sepsis with bloodstream infection. Both models were constructed from randomly chosen subsets of patients and subsequently were evaluated on the remaining (independent) patients. RESULTS Survival after sepsis was predicted with an accuracy of 80% by the NN model, which used only information collected at the time of the diagnosis of sepsis. The development of multiple organ failure after the diagnosis of sepsis was predicted accurately (81.5%) with either the MLR or the NN model. Both the MLR and the NN methods depended on the interpretation of a likelihood quantity, requiring the choice of a threshold to make a survival prediction. The accuracy of the MLR models was very sensitive to the threshold value. The accuracy of the NN models was not sensitive to the choice of threshold, because they generated likelihood predictions that were distributed far from the middle range where the threshold was placed. CONCLUSION Compared with MLR models, the NN models were slightly more accurate and much less sensitive to the arbitrary threshold parameter.
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Affiliation(s)
- J R Flanagan
- University of Iowa College of Medicine, Iowa City, USA
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8552
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Pangborn W, Erman M, Li N, Burkhart BM, Pletnev VZ, Duax WL, Gutierrez R, Peirano A, Eyzaguirre J, Thiel DJ, Ghosh D. Characterization of crystals of Penicillium purpurogenum acetyl xylan esterase from high-resolution x-ray diffraction. Proteins 1996; 24:523-4. [PMID: 8860002 DOI: 10.1002/(sici)1097-0134(199604)24:4<523::aid-prot13>3.0.co;2-n] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Acetyl xylan esterase from Penicillium purpurogenum, a single-chain 23 kDa member of a newly characterized family of esterases that cleaves side chain ester linkages in xylan, has been crystallized. The crystals diffract to better than 1 A resolution at the Cornell High Energy Synchrotron Source (CHESS) and are highly stable in the synchrotron radiation. The space group is P2(1)2(1)2(1) and cell dimensions are a = 34.9 A, b = 61.0 A, C = 72.5 A.
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Affiliation(s)
- W Pangborn
- Hauptman-Woodward Medical Research Institute, Inc., Buffalo, New York 14203, USA
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8553
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Abstract
To investigate the effect of endogenous cholesterol synthesis on blood pressure and vascular response, a HMG CoA reductase inhibitor, pravastatin (1 or 10 mg/kg per day) was administered orally for 2 or 4 weeks to spontaneously hypertensive rats (SHR/lzm) and normotensive Wistar-Kyoto (WKY/lzm) rats. Blood pressure was significantly increased in the pravastatin-treated groups of both strains, occurring in WKY after a longer treatment period than in SHR. The thoracic aortas from SHR and WKY were pretreated with pravastatin (10(-4)M). The vascular response to norepinephrine in terms of both contractility and sensitivity, was increased in the pravastatin-treated SHR aorta but not in the WKY aorta. The increased response was not observed in the presence of mevalonate. Acetylcholine-induced vascular relaxation in the aortas from both strains was not affected by pravastatin pretreatment. These results suggest that the vascular response to norepinephrine may be affected by the intracellular cholesterol synthesis pathway.
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Affiliation(s)
- N Li
- Graduate School of Human and Environmental Studies, Kyoto University, Japan
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8554
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Pittet D, Thiévent B, Wenzel RP, Li N, Auckenthaler R, Suter PM. Bedside prediction of mortality from bacteremic sepsis. A dynamic analysis of ICU patients. Am J Respir Crit Care Med 1996; 153:684-93. [PMID: 8564118 DOI: 10.1164/ajrccm.153.2.8564118] [Citation(s) in RCA: 163] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The prognosis in patients with sepsis depends on severity of acute illness, underlying chronic diseases, and complications associated with infection. Adjusting for these factors is essential for evaluation of new therapies. The purpose of the present study was to determine variables readily identifiable at the bedside that predict mortality in intensive care unit (ICU) patients with sepsis and positive blood cultures. For a 5-yr period, all patients of a surgical ICU presenting with positive blood cultures and sepsis were systematically analyzed for clinical variables and organ dysfunctions at the day of onset of sepsis and bacteremia and during the subsequent clinical course. The prognostic value of these variables was determined using logistic regression procedures. Of the 5,457 admissions to the ICU, 176 patients developed sepsis with positive blood cultures (3.2 per 100 admissions). The fatality rate was 35% at 28 days after the onset of sepsis; in-hospital mortality was 43%. Independent predictors of mortality at onset of sepsis were previous antibiotic therapy (odds ratio [OR], 2.40; 95% confidence interval [CI95], 1.59 to 3.62; p = 0.034), hypothermia (OR, 1.43; CI95, 1.04 to 2.44; p = 0.030), requirement for mechanical ventilation (OR, 2.97; CI95, 1.96 to 4.51; p = 0.009), and onset-of-sepsis APACHE II score (OR, 1.21; CI95, 1.13 to 1.29; p < 0.001). Vital organ dysfunctions developing after the onset of sepsis influenced outcome markedly. The best two independent prognostic factors were the APACHE II score at the onset of sepsis (OR, 1.13 per unit; CI95, 1.08 to 1.17; p = 0.0016) and the number of organ dysfunctions developing thereafter (OR, 2.39; CI95, 2.02 to 2.82; p < 0.001). In ICU patients with sepsis and positive blood cultures, outcome can be predicted by the severity of illness at onset of sepsis and the number of vital organ dysfunctions developing subsequently. These variables are easily assessed at the bedside and should be included in the evaluation of new therapeutic strategies.
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Affiliation(s)
- D Pittet
- Department of Internal Medicine, University Hospital of Geneva, Switzerland
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8555
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Abstract
A series of nested N-terminal deletions were made on the full-length (wt) and C-terminal deleted (Cdel) 1-aminocyclopropane-1-carboxylate synthase cDNAs. These wt and mutant ACC synthases were over-expressed in a heterologous E. coli expression system. It was found that removal of an amino acid region (residues 2-12) from the non-conserved N-termini of wt and Cdel ACC synthases led to a slight increase in both in vivo ACC production and in vitro ACC synthase activity. Further deletion of 11 amino acids through Glu-23 from the N-termini of both wt and Cdel ACC synthases resulted in a substantial reduction in both in vivo ACC production and in vitro enzyme activity. Deletion of an amino acid region, residues 3 through 27, from the N-terminus of ACC synthase abolished enzyme activity completely. Kinetic analysis of a highly purified double-deletion mutant (NCdel-1) of ACC synthase demonstrated that the Km of this mutant is 42 microM, which is much smaller than that of the corresponding Cdel (280 microM) and closer to that of wt (22 microM) reported previously, suggesting a clear effect of the non-conserved N-terminal region on its ACC synthase function.
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Affiliation(s)
- N Li
- Department of Biology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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8556
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Li N, Li KA, Tong SY. Fluorometric determination for micro amounts of albumin and globulin fractions without separation by using alpha, beta, gamma, delta-tetra(4'-carboxyphenyl)porphin. Anal Biochem 1996; 233:151-5. [PMID: 8789712 DOI: 10.1006/abio.1996.0022] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A simultaneous determination of micro amounts of albumin and globulin fractions by fluorometry with only reagent alpha,beta,gamma,delta-tetra(4'-carboxyphenyl)porphin (TCPP) in the aqueous solution has been developed. Under the experimental conditions (5.6 x 10(-7) mol/liter of TCPP, pH 3.0, and at room temperature), the linear range of this assay was 0.09-12 microgram/ml and the detection limits (3 S/N) were 60 ng/ml for albumin and 90 ng/ml for globulin, respectively. The human serum samples were measured satisfactorily by using this method.
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Affiliation(s)
- N Li
- Department of Chemistry, Peking University, Beijing, People's Republic of China
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8557
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Li N, Sawamura M, Nara Y, Ikeda K, Yamori Y. Direct inhibitory effects of taurine on norepinephrine-induced contraction in mesenteric artery of stroke-prone spontaneously hypertensive rats. Adv Exp Med Biol 1996; 403:257-62. [PMID: 8915362 DOI: 10.1007/978-1-4899-0182-8_27] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The effect of taurine on vascular reactivity was investigated in the mesenteric artery of Wistar Kyoto (WKY), and stroke-prone spontaneously hypertensive rats (SHRSP). Administration of taurine significantly decreased blood pressure of SHRSP but not WKY. The mesenteric artery of taurine-treated SHRSP was excised to observe the contractile responses to transmural electrical stimulation and to several vasoactive substances. Vasocontraction induced by norepinephrine (NE) was significantly decreased by taurine. However, contraction elicited by the other substances tested was not affected. Consistently, when the vessels of SHRSP were pretreated with taurine in vitro, only the NE-induced vasocontraction was specifically attenuated. No effect was observed in WKY vessels. These results indicate that the hypotensive effect of taurine is accounted for at least in part its direct action on blood vessels.
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Affiliation(s)
- N Li
- Graduate School of Human and Environmental Studies, Kyoto University, Japan
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8558
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Ni AP, Lin GY, Yang L, He HY, Huang CW, Liu ZJ, Wang RS, Zhang JS, Yu JY, Li N, Wang JB, Yang HY. A seroepidemiologic study of Chlamydia pneumoniae, Chlamydia trachomatis and Chlamydia psittaci in different populations on the mainland of China. Scand J Infect Dis 1996; 28:553-7. [PMID: 9060055 DOI: 10.3109/00365549609037959] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To evaluate and compare the prevalence of antibodies to 3 chlamydial species in various populations on the mainland of China, the MIF test was used to detect both serum IgG and IgM antibodies to these species in the normal population (n = 711), in poultry workers (n = 51), in female prostitutes (n = 106), in patients attending the sexually transmitted diseases clinic (n = 98), and in adult patients with pneumonia and bronchitis (n = 108). In the normal population, IgG antibodies against C. pneumoniae, C. trachomatis and C. psittaci were present in 61.5%, 9.3%, and 3.5%, respectively, and increasing with age. Prevalence and geometric mean titers (GMT) of IgG antibodies to C. trachomatis in prostitutes (54.7%) and female (55%), but not male (15.4%) sexually transmitted disease patients were significantly higher than in the normal adult female population. The prevalence indicating both previous and recent C. psittaci infections in poultry workers was no higher than in the others. The prevalence of IgG antibodies and GMT to C. pneumoniae in patients with pneumonia and bronchitis was not statistically higher than in the normal adult population. Evidence of cross-reactivities in the MIF test between different species was found in both prevalence and GMT. Serum IgM antibodies were usually absent in patients who met the serological criteria of recent C. pneumoniae infection, indicating that most of them could be considered as reinfections. On the basis of our survey, acute antibodies to C. pneumoniae by the MIF test, if they are detected, may be valuable in the diagnosis of recent C. pneumoniae infections.
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Affiliation(s)
- A P Ni
- Department of Clinical Laboratories, Peking Union Medical College Hospital, CAMS, Beijing PR China
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8559
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Li N, Sawamura M, Nara Y, Kizawa K, Ikeda K, Usui H, Kurahasi K, Yamori Y. HMG-CoA reductase inhibitor affects blood pressure and vascular reactivity. Clin Exp Pharmacol Physiol Suppl 1995; 22:S316-7. [PMID: 9072408 DOI: 10.1111/j.1440-1681.1995.tb02934.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
1. To investigate the effect of endogenous cholesterol synthesis on blood pressure and vascular response, a HMG CoA reductase inhibitor, pravastatin (1 or 10 mg/kg) was administered orally for 2 or 4 weeks to 8-13 week old spontaneously hypertensive rats (SHR/Izm) and normotensive Wistar-Kyoto (WKY/Izm) rats. 2. Blood pressure was significantly increased in the pravastatin-treated groups of both strains, but the elevation was observed in WKY after a longer treatment than in SHR. 3. After the thoracic aorta from 10-12 week old SHR and WKY was pretreated with pravastatin (10(-4) mol/L), the vascular response to norepinephrine was increased in pravastatin-treated SHR aorta but not in the WKY aorta in both contractivity and sensitivity. 4. These experiments suggest that the vascular response is affected by intracellular cholesterol synthesis pathway.
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Affiliation(s)
- N Li
- Graduate School of Human and Environmental Studies, Kyoto University, Japan
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8560
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Froimowitz M, Deng Y, Jacob JN, Li N, Cody V. Dopaminergic (4aR,10bS)-cis- and (4aS,10bS)-trans-octahydrobenzo[F]quinolines have similar pharmacophores. Drug Des Discov 1995; 13:73-81. [PMID: 8882902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The structures and absolute configurations of two N-phenethyl substituted cis- and trans-octahydrobenzo[f]quinolines were determined by X-ray crystallography. The absolute configurations of the enantiomers that have high affinity for dopaminergic receptors were found to be (4aR,10bS) and (4aS,10bS) for the (-)-cis- and (-)-trans-8,9-dihydroxy substituted compounds. This is consistent with previous results for a dopamine agonist pharmacophore. MM2-87 calculations for a cis isomer, which has two alternative chair conformations of the piperidine ring, indicated that the preferred conformer is the same as that observed in the crystal structure. Superposition of the more active cis and trans enantiomers showed that the three dimensional orientations of the phenyl ring and the ammonium group are similar in the two geometrical isomers. The cis isomer, however, has steric bulk out of the plane of the molecule and this appears to result in a loss of agonist efficacy. The addition of the N-phenethyl group to the 7-OH and 7,8-diOH cis compounds, however, appears to be sufficient to restore high affinity for dopaminergic receptors unlike previously synthesized cis compounds. These cis compounds, however, appear to be mixed agonist/antagonists or antagonists on functional assays of dopaminergic activity.
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Affiliation(s)
- M Froimowitz
- Alcohol and Drug Abuse Research Center, McLean Hospital, Harvard Medical School, Belmont, MA 02178, USA
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8561
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O'Reilly JM, Li N, Duax WL, Brueggemeier RW. Synthesis, structure elucidation, and biochemical evaluation of 7 alpha- and 7 beta-arylaliphatic-substituted androst-4-ene-3,17-diones as inhibitors of aromatase. J Med Chem 1995; 38:2842-50. [PMID: 7636845 DOI: 10.1021/jm00015a006] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The inhibition of aromatase, the cytochrome P450 enzyme complex responsible for the conversion of androgens to estrogens, may be useful for the endocrine treatment of breast cancer. Previously, several 7 alpha-thio-substituted androstenediones have been shown to be potent inhibitors of aromatase. Recent research has focused on producing a more metabolically stable aromatase inhibitor by replacing the carbon-sulfur bond at the 7 alpha-position with a carbon-carbon bond. The new inhibitors, 7 alpha-arylaliphatic-substituted androst-4-ene-3,17-diones (2-4), have alkyl chains of varying length between the steroid and the aryl ring at the 7 alpha-position. The desired targets were synthesized via a 1,6-conjugate addition of the appropriate cuprate to 17 beta-(tert-butyldimethylsiloxy)androsta-4,6-dien-3-one (7). The synthesis also resulted in the formation of the 7 beta-substituted diastereomers (10-11 and 13) as minor products. Initial assignments of the 7 alpha-phenethyl and 7 beta-phenethyl diastereomers were made using highfield 1-D and 2-D NMR studies. The assignment of the diastereomers was confirmed using X-ray crystallography. These compounds were all good inhibitors of aromatase in vitro when assayed using microsomes isolated from human placenta. The 7 alpha-substituted androst-4-ene-3,17-diones (2-4) were effective inhibitors with apparent Kis of 13-19 nM. The corresponding 17 beta-hydroxy analogs (8 and 14) and the 7 beta-substituted androstenediones (13 and 16) were less effective inhibitors with apparent Kis of 36-44 nM. Thus, a new series of 7 alpha-arylaliphatic-substituted androst-4-ene-3,17-diones has been synthesized, and the compounds are potent competitive inhibitors of aromatase.
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Affiliation(s)
- J M O'Reilly
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, Ohio State University, Columbus 43210, USA
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8562
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Abstract
Manganese superoxide dismutase (MnSOD) levels were monitored as a function of time in culture to determine whether these levels were altered at logarithmic growth versus when the cells exhibited density limitation of growth. For comparison, activities of the antioxidant enzymes copper, zinc superoxide dismutase (CuZnSOD), catalase, and glutathione peroxidase were also evaluated. Four cell lines were studied, two of which exhibited density limitation of growth and two of which did not. Each cell line showed a unique antioxidant enzyme profile. The two cell lines that showed density limitation of growth also demonstrated induction of MnSOD at the time when the cells stopped proliferating in culture, whereas the other two cell lines did not show induction of MnSOD. There was no strict correlation between density limitation of growth and activities of the other antioxidant enzymes. To determine whether SOD varied with various phases of the cell cycle, NIH/3T3 cells were synchronized using serum starvation, and then SOD activities were measured during quiescence (G0) and the phase of DNA synthesis (S-phase). MnSOD was decreased during S-phase compared with G0, whereas CuZnSOD was increased during S-phase compared with G0, demonstrating alteration of SOD activities with varying phases of the cell cycle. This study suggests the possibility that increased MnSOD may correlate with decreased cell proliferation and suggests significant alterations in SOD activities during the cell cycle.
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Affiliation(s)
- T D Oberley
- Department of Pathology, University of Wisconsin Medical School, Madison, USA
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8563
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8564
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Mao Q, Chen J, Li N, Li C, Mao B, Wang R, Wu G. [The value of serum myelin basic protein in assessment of severity of acute closed head trauma]. Hua Xi Yi Ke Da Xue Xue Bao 1995; 26:135-7. [PMID: 7490016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Serum levels of myelin basic protein (MBP) were measured in 112 patients after acute head injury by enzyme linked immuno-absorbent assay (ELISA). Patients with cerebral concussion showed no significant change in serum MBP. Patients with cerebral contusion, extradural hematoma or intracerebral hematoma had a mean serum MBP concentration much higher than that of patients with cerebral concussion. And patients with extradural hematoma had a mean serum MBP concentration much lower than that of patients with cerebral contusion and intracerebral hematoma; the differences were significant (P < 0.05). But there was no significant difference between patients with cerebral contusion and intracerebral hematoma (P > 0.05). The amount of serum MBP was significantly correlated with the volume of extradural hematoma, intracerebral hematoma and with the extent of the cerebral contusion (P < 0.05). This study suggested that the serum MBP may reflect the type and severity of closed head injury patients.
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8565
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Pittet D, Rangel-Frausto S, Li N, Tarara D, Costigan M, Rempe L, Jebson P, Wenzel RP. Systemic inflammatory response syndrome, sepsis, severe sepsis and septic shock: incidence, morbidities and outcomes in surgical ICU patients. Intensive Care Med 1995; 21:302-9. [PMID: 7650252 DOI: 10.1007/bf01705408] [Citation(s) in RCA: 191] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVES To determine the incidence of systemic inflammatory response syndrome (SIRS), sepsis and severe sepsis in surgical ICU patients and define patient characteristics associated with their acquisition and outcome. DESIGN One-month prospective study of critically ill patients with a 28 day in-hospital follow up. SETTING Surgical intensive care unit (SICU) at a tertiary care institution. METHODS All patients (n = 170) admitted to the SICU between April 1 and April 30, 1992 were prospectively followed for 28 days. Daily surveillance was performed by two dedicated, specifically-trained research nurses. Medical and nursing chart reviews were performed, and follow up information at six and twelve months was obtained. RESULTS The in-hospital surveillance represented 2246 patient-days, including 658 ICU patient-days. Overall, 158 patients (93%) had SIRS for an incidence of 542 episodes/1000 patients-days. The incidence of SIRS in the ICU was even higher (840 episodes/1000 patients-days). A total of 83 patients (49%) had sepsis; among them 28 developed severe sepsis. Importantly, 13 patients had severe sepsis after discharge from the ICU. Patient groups were comparable with respect to age, sex ratio, and type of surgery performed. Apache II score on admission to the ICU and ASA score at time of surgery were significantly higher (p < 0.05) only for patients who subsequently developed severe sepsis. The crude mortality at 28 days was 8.2% (14/170); it markedly differed among patient groups: 6% for those with SIRS vs. 35% for patients with severe sepsis. Patients with sepsis and severe sepsis had a longer mean length of ICU stay (2.1 +/- 0.2 and 7.5 +/- 1.5, respectively) than those with SIRS (1.45 +/- 0.1) or control patients (1.16 +/- 0.1). Total length of hospital stay also markedly differed among groups (35 +/- 9 (severe sepsis), 24 +/- 2 (sepsis), 11 +/- 0.8 (SIRS), and 9 +/- 0.1 (controls, respectively). CONCLUSIONS Almost everyone in the SICU had SIRS. Therefore, because of its poor specificity, SIRS was not helpful predicting severe sepsis and septic shock. Patients who developed sepsis or severe sepsis had higher crude mortality and length of stay than those who did not. Studies designed to identify those who develop complications of SIRS would be very useful.
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Affiliation(s)
- D Pittet
- Division of General Medicine, University of Iowa College of Medicine, Iowa City, USA
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8566
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Li N, Seetharam S, Seetharam B. Genomic structure of human transcobalamin II: comparison to human intrinsic factor and transcobalamin I. Biochem Biophys Res Commun 1995; 208:756-64. [PMID: 7695633 DOI: 10.1006/bbrc.1995.1402] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Human transcobalamin II (TC II) gene was isolated and partially sequenced. The gene is composed of nine exons and eight introns spanning approximately 20 kb. Multiple potential transcription start sites were revealed by primer extension analysis. The 5'-flanking region of the gene contained no TATA-like motif, but a binding motif for HIP1, which is suggested to be important in the transcription of TATA-less housekeeping genes, was identified in a region very close to the initiator methionine codon. In addition, potential binding sites for a variety of transcription factors such as SP1, AP2, CF1, NF-IL6, Ets-1, Myb and E2A were also observed. Comparison of the genomic structure of TC II to other Cbl-binding proteins, human gastric intrinsic factor (IF) and transcobalamin I (TC I) revealed similar intron-exon organizations with respect to the number, position and size of exons. These results suggest that TC II, TC I and IF genes have originated by gene duplications of an ancestral gene and TC II, unlike the other two Cbl-binding proteins, is the product of a "housekeeping" gene.
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Affiliation(s)
- N Li
- Department of Medicine, Medical College of Wisconsin, Milwaukee
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8567
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Ghosh D, Wawrzak Z, Pletnev VZ, Li N, Kaiser R, Pangborn W, Jörnvall H, Erman M, Duax WL. Structure of uncomplexed and linoleate-bound Candida cylindracea cholesterol esterase. Structure 1995; 3:279-88. [PMID: 7788294 DOI: 10.1016/s0969-2126(01)00158-7] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Candida cylindracea cholesterol esterase (CE) reversibly hydrolyzes cholesteryl linoleate and oleate. CE belongs to the same alpha/beta hydrolase superfamily as triacylglycerol acyl hydrolases and cholinesterases. Other members of the family that have been studied by X-ray crystallography include Torpedo californica acetylcholinesterase, Geotrichum candidum lipase and Candida rugosa lipase. CE is homologous to C. rugosa lipase 1, a triacylglycerol acyl hydrolase, with which it shares 89% sequence identity. The present study explores the details of dimer formation of CE and the basis for its substrate specificity. RESULTS The structures of uncomplexed and linoleate-bound CE determined at 1.9 A and 2.0 A resolution, respectively, reveal a dimeric association of monomers in which two active-site gorges face each other, shielding hydrophobic surfaces from the aqueous environment. The fatty-acid chain is buried in a deep hydrophobic pocket near the active site. The positioning of the cholesteryl moiety of the substrate is equivocal, but could be modeled in the hydrophobic core of the dimer interface. CONCLUSIONS The monomer structure is the same in both the complexed and uncomplexed crystal forms. The dimers differ in the relative positions of the two monomers at the dimer interface. Of the 55 residues that are different in CE from those in C. rugosa lipase 1, 23 are located in the active site and at the dimer interface. The altered substrate specificity is a direct consequence of these substitutions.
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Affiliation(s)
- D Ghosh
- Hauptman-Woodward Medical Research Institute, Inc., Buffalo, NY 14203-1196, USA
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8568
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Abstract
In China in recent years, male live births have exceeded those of females by amounts far greater than those that occur naturally in human populations, a trend with significant demographic consequences. The resulting imbalance in the first-marriage market is estimated to be about 1 million males per year after 2010. These "excess" males were not easily accommodated in models with substantial changes in first-marriage patterns. The current sex ratio at birth has little effect on a couple's probability of having at least one son, so future increases in the sex ratio may well occur, especially given increasing access to sex-selective abortion.
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Affiliation(s)
- S Tuljapurkar
- Morrison Institute for Population and Resource Studies, Department of Bioloical Sciences, Stanford University, CA 94305
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8569
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Li N, Tuljapurkar S, Feldman M. High sex ratio at birth and its consequences. Chin J Popul Sci 1995; 7:213-21. [PMID: 12290857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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8570
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Zhao Y, Li J, Li N, Liao C. Absorptive function of segmental allotransplanted small intestines in pigs. Chin Med J (Engl) 1995; 108:15-9. [PMID: 7536142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Ten outbred pigs were each operated on for three times. First, a 130 cm length of terminal ileum of each pig was isolated on its vascular pedicle as a Thirty-Vella loop. One week later, the solitary ileal segments were transplanted heterotopically in two pigs. And after 28 days of heterotopic transplantation, the transplanted intestine was interposed into continuity of host intestine as orthotopic transplant. During the experiment, tests were made on 6th day after the first operation (period I), the 14th (II), 28th (III) day after heterotopic transplantation, and 3 weeks after interposition (IV) respectively for the levels of glucose, palmitate and leucine. Additionally, at period I, III, and IV, a 3 cm length of intestinal mucosa was excised for morphologic observation and determination of DNA, RNA and protein contents. After heterotopic transplantation, the absorptive function of transplanted intestine was severely impaired for two weeks. The absorption of glucose and palmitate was partially recovered by period III, at which time leucine level had return to normal. At period IV, the absorptive function of glucose and leucine had surpassed normal levels, while palmitate had risen to the level of pretransplantation. After transplantation, at period III, DNA, RNA and protein contents were well below normal. Three weeks after orthotopic transplantation, RNA and protein had risen to normal level, while DNA content remained below normal. The morphologic changes during the experiment were correlated with the changes of contents in RNA, protein and DNA.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- Y Zhao
- Department of Abdominal Surgery, Nanjing PLA General Hospital
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8571
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Li N, Li J, Li Y. [Experimental and clinical studies of small bowel allotransplantation]. Zhonghua Wai Ke Za Zhi 1995; 33:11-4. [PMID: 7774436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The pigs with allograft were divided into 5 groups according to the different immunosuppressive regimens. Acute rejection of allograft occurred in animals not treated with immunosuppressive agents or treated with low dose of cyclosporine (CsA). There was no rejection developed in the pigs treated with high dose CsA or low dose CsA and tripterygium wilfordii (TW). No evidence of chronic rejection was detected in animals with continued administration of TW after living longer than 100 days when the immunosuppressive treatment was discontinued. A woman with enterocolitis, ileus and short-gut syndrome received a complete cadaveric small bowel transplantation in march 12, 1994. The graft had 6 minutes for warm ischemia and 9 hours and 45 minutes for cold ischemia. The immunosuppressive therapy consisted of CsA, TW and methylprednisolone. The patient is alive and the function of graft is normal.
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Affiliation(s)
- N Li
- Nanjing General Hospital of People's Liberation Army
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8572
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Blaikie P, Immanuel D, Wu J, Li N, Yajnik V, Margolis B. A region in Shc distinct from the SH2 domain can bind tyrosine-phosphorylated growth factor receptors. J Biol Chem 1994; 269:32031-4. [PMID: 7798194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Shc is a ubiquitously expressed Src homology 2 (SH2) domain protein that can transform fibroblasts and differentiate PC12 cells in a Ras-dependent fashion. Shc binds a variety of tyrosine-phosphorylated growth factor receptors presumably via its carboxyl-terminal SH2 domain. We cloned a fragment of Shc when screening a bacterial expression library with tyrosine-phosphorylated epidermal growth factor (EGF) receptor. Surprisingly, this fragment encodes the amino terminus of Shc, a region that has no significant similarity to an SH2 domain. When expressed as a glutathione S-transferase fusion protein, this amino-terminal domain binds to autophosphorylated EGF receptor, as well as HER2/neu and TrkA receptors. This fragment acts like an SH2 domain in that it does not bind non-phosphorylated EGF receptor or EGF receptor with all tyrosine phosphorylation sites mutated or deleted. Our data define a novel domain in Shc that has the potential to interact with growth factor receptors and other tyrosine-phosphorylated proteins.
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Affiliation(s)
- P Blaikie
- Department of Pharmacology, New York University Medical Center, New York 10016
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8573
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Blaikie P, Immanuel D, Wu J, Li N, Yajnik V, Margolis B. A region in Shc distinct from the SH2 domain can bind tyrosine-phosphorylated growth factor receptors. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)31593-x] [Citation(s) in RCA: 186] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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8574
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Li N, Schlessinger J, Margolis B. Autophosphorylation mutants of the EGF-receptor signal through auxiliary mechanisms involving SH2 domain proteins. Oncogene 1994; 9:3457-65. [PMID: 7970705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Many growth factors bind and activate receptors with intrinsic protein tyrosine kinase activity. Once activated these receptors undergo autophosphorylation allowing them to bind src homology 2 (SH2) domain proteins. We mutated or deleted all known autophosphorylation sites of the Epidermal Growth Factor-Receptor (EGF-receptor) and examined the effects of these mutations on gene expression, MAP kinase activation and mitogenesis. We find that the mutant receptors, although unable to bind SH2 domain proteins, are fully competent to activate all these signaling pathways. Our data indicates that these mutant receptors utilize several different compensatory mechanisms to overcome the lack of autophosphorylation sites. One mechanism is the use of tyrosine phosphorylated cellular proteins as surrogates for binding SH2 domain proteins. We find that all these mutant receptors can induce tyrosine phosphorylation of Shc which then acts as a binding site for the Grb2/Sos signaling complex. This data indicates that even though autophosphorylation mutants of the EGF-receptor cannot directly bind SH2 domain proteins, they are able to use auxiliary signals that result in activation of SH2 domain proteins crucial for mitogenesis.
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Affiliation(s)
- N Li
- Department of Pharmacology, New York University Medical Center, NY 10016
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8575
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Zaridze DG, Li N, Men T, Duffy SW. Childhood cancer incidence in relation to distance from the former nuclear testing site in Semipalatinsk, Kazakhstan. Int J Cancer 1994; 59:471-5. [PMID: 7960215 DOI: 10.1002/ijc.2910590407] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Rates of childhood cancer between 1981 and 1990 in the 4 administrative zones of Kazakhstan were studied to assess the relationship, if any, with distance from nuclear testing sites. Risk of various cancers among children aged 14 years or younger were estimated in relation to distance from (1) a site where testing in air was performed before 1963, (2) a site where underground testing took place thereafter, and (3) a reservoir, known as "Atom Lake," created by 4 nuclear explosions in 1965. Risk of acute leukaemia rose significantly with increasing proximity of residence to the testing areas, although the absolute value of the risk gradient was relatively small. The relative risk for those living less than 200 km from the air-testing site was 1.76 compared with those living 400 km or more away from the site. Similar relative risks were observed for the underground site and "Atom Lake." There was also some evidence of increased risk of brain tumours in association with proximity to the test sites. In 2 of the 4 zones studied, there was substantial regional variation in acute leukaemia rates which was not attributable to distance from the test site. The findings may be affected by potential confounders, notably urban/rural status and ethnic factors.
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Affiliation(s)
- D G Zaridze
- Department of Epidemiology, Cancer Research Center RAMS, Moscow, Russian Federation
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8576
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Abstract
Reverse transcription-polymerase chain reaction has been used to amplify, clone and sequence transcobalamin II (TC II) cDNA from fibroblasts of three unrelated TC II deficient patients who had undetectable TC II protein and mRNA in their fibroblasts (Li et al., Biochem. J, 301, 585-590, 1994). One child of a consanguineous marriage contained a single nucleotide deletion at position 258 in both alleles, while the child from unrelated parents revealed a nonsense mutation at position 1206 in one allele and a single nucleotide deletion at position 483 in the other allele. Both the single nucleotide deletion mutations caused a frameshift and introduced a premature termination codon (indirect nonsense mutations). No mutation was detected in TC II cDNA from the third patient. Based on these results we suggest that TC II deficiency due to lack of TC II protein/mRNA in these patients is due to heterogeneous types of nonsense mutations.
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Affiliation(s)
- N Li
- Department of Medicine, Medical College of Wisconsin, Milwaukee
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8577
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Li N, Sood GK, Seetharam S, Seetharam B. Polymorphism of human transcobalamin II: substitution of proline and/or glutamine residues by arginine. Biochim Biophys Acta 1994; 1219:515-20. [PMID: 7918650 DOI: 10.1016/0167-4781(94)90079-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The sequence of transcobalamin II (TC II) cDNA amplified from human fibroblast and colon adenocarcinoma (Caco-2) and the electrophoretic mobility of TC II secreted by these cell lines were analyzed to get some insights into the structural basis for the expression of various polymorphic forms of human TC II. Based on relative anodic mobilities of TC II phenotypes expressed in human serum, TC II expressed in the fibroblast cell line studied and Caco-2 cells were assigned as the MX (medium/extremely slow) and S (slow) types, respectively. Nucleotide sequence analysis of TC II cDNA amplified from these cells revealed that residues Arg and Arg, Gln and Arg, and Gln and Pro were present at positions 234 and 259, respectively, in TC II alleles encoding the X, S and M types. Based on these results, we suggest that differences in the anodic mobilities of the various polymorphic forms of TC II such as the X, S and M types are due to charge difference on the protein caused by the replacement of uncharged residues by arginine at positions 234 and/or 259.
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Affiliation(s)
- N Li
- Department of Medicine, Medical College of Wisconsin, Milwaukee
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8578
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Abstract
Transcobalamin II (TC II) deficiency is a rare autosomal recessive disease leading to cobalamin (Cbl; Vitamin B12) deficiency characterized by failure to thrive, megaloblastic anemia, impaired immunodefence and neurological manifestations. By means of Southern blotting and sequence analysis of TC II cDNA amplified from fibroblasts of an affected child and his parents, we have identified two mutant TC II alleles, one with a gross deletion and the other with a 4 nucleotide deletion. Both the mutations caused TC II mRNA and protein deficiency and hence defective plasma transport of Cbl and the development of Cbl deficiency in the affected child. The present study has identified molecular defects that cause TC II deficiency and lead to intracellular Cbl deficiency in humans.
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Affiliation(s)
- N Li
- Department of Medicine, Medical College of Wisconsin, Milwaukee 53226
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8579
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Aronheim A, Engelberg D, Li N, al-Alawi N, Schlessinger J, Karin M. Membrane targeting of the nucleotide exchange factor Sos is sufficient for activating the Ras signaling pathway. Cell 1994; 78:949-61. [PMID: 7923364 DOI: 10.1016/0092-8674(94)90271-2] [Citation(s) in RCA: 386] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Activation of growth factor receptors results in tyrosine autophosphorylation and recruitment of SH2 domain-containing effectors, including Grb2. Grb2 recruitment mediates activation of the Ras nucleotide exchanger Sos by an unknown mechanism. To examine the role of membrane recruitment, we prepared Sos derivatives containing either myristoylation or farnesylation signals. This resulted in plasma membrane targeting of Sos and stimulation of the Ras signaling pathway, including ERK and AP-1 activities leading to oncogenic transformation. Sos derivatives with nonfunctional myristoylation or farnesylation sequences were inactive. Farnesylation of Sos also activated Ras signaling in yeast. In both mammalian cells and yeast, membrane-targeted Sos derivatives lacking the C-terminal region were considerably more active. Therefore, targeting of Sos to the plasma membrane in the vicinity of Ras appears to be the primary mechanism leading to activation of the Ras pathway. A secondary mechanism could involve relief of the inhibitory effect of the Sos C-terminal region.
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Affiliation(s)
- A Aronheim
- Department of Pharmacology, University of California, San Diego, La Jolla 92093-0636
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8580
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Affiliation(s)
- D Zhou
- Department of Horticulture, University of Maryland, College Park 20742
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8581
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Li N, Seetharam S, Rosenblatt DS, Seetharam B. Expression of transcobalamin II mRNA in human tissues and cultured fibroblasts from normal and transcobalamin II-deficient patients. Biochem J 1994; 301 ( Pt 2):585-90. [PMID: 7913804 PMCID: PMC1137121 DOI: 10.1042/bj3010585] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Transcobalamin II (TCII) is an important plasma transporter of cobalamin (Cbl; vitamin B12). In the present study, TCII gene expression in human and rat tissues and in the fibroblasts of patients with TCII deficiency was investigated. Northern-blot analyses revealed expression of TCII mRNA in many human and rat tissues. In humans, this was 14-fold higher in the kidney than in liver, whereas in the rat the levels of expression were similar in the kidney and liver. Southern-blot analysis of genomic DNA from several species revealed sequence similarity in TCII across species. Metabolic labelling and ribonuclease protection assay revealed a 43 kDa TCII protein and a fully protected TCII mRNA band in normal fibroblasts but not in fibroblasts from three TCII-deficient patients. Southern-blot analysis of genomic DNA from all these fibroblasts revealed identical restriction patterns on BamHI, HindIII, KpnI, MspI and EcoRI digestion. On the basis of these results, we suggest that TCII is expressed in multiple tissues, and its level of expression in tissues varies within the same and across species. Furthermore, the TCII deficiency characterized in this study is due to the absence of TCII protein which in turn is due to the absence or extremely low levels of its mRNA and not to detectable gross alterations in the gene structure.
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Affiliation(s)
- N Li
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee 53226
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8582
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Li N, Tuomilehto J, Dowse G, Virtala E, Zimmet P. Prevalence of coronary heart disease indicated by electrocardiogram abnormalities and risk factors in developing countries. J Clin Epidemiol 1994; 47:599-611. [PMID: 7722573 DOI: 10.1016/0895-4356(94)90208-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A cross-sectional population survey was carried out in 15 population groups (ethnicity includes Melanesian, Polynesian, Micronesian, Asian Indian and Chinese) in 9 developing countries: Fiji, Nauru, Kiribati, Cook Island, Niue, Western Samoa, New Caledonia, Mauritius and China (Beijing) in 1978-1987. The total sample included 4594 men and 4988 women aged 35-59 years. The aim of study is to report the prevalence of coronary heart disease (CHD) as indicated by ECG Minnesota coding, and risk factor levels and to describe the individual and ecological relationship between CHD prevalence and CHD risk factors among different ethnic groups in developing countries. Mauritians had the highest prevalence of CHD of these countries. Total serum cholesterol concentration and the prevalence of CHD were higher in Mauritius Chinese than in Beijing Chinese. Mean total cholesterol was lower than or equal to 5.2 mmol/l (200 mg/dl) in all population groups, except in Mauritians. Hypertensive subjects in most populations had a low cholesterol concentration. The prevalence of hypertension varied from 7 to 35% and mean body mass index (BMI) from 22.9 to 37.0 kg/m2. Smoking was more common in men (36-82%) than women (0.8-65%). Multiple logistic regression analysis using individuals as a unit of analysis showed that cholesterol and systolic blood pressure were significant independent predictors of CHD prevalence. When fasting or 2 hr post-load blood glucose was included in the model total cholesterol was no longer significant in men but remained significant in women. Ecological analysis using populations as units of analysis showed that the combination of several CHD risk factors could explain about 90% of the interpopulations variance of the CHD prevalence in women. The best models were those where 2 hr post-load glucose was included. Our study has demonstrated that the total cholesterol concentration of the population was consistent with the prevalence of CHD in the population. A considerable proportion of the variation in CHD prevalence across populations in developing countries can be explained by well-known risk factors. These data support the concept that retaining traditional balanced dietary habits and limiting salt intake together with avoiding smoking use are important activities for the prevention of cardiovascular disease (CVD) in developing countries.
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Affiliation(s)
- N Li
- Department of Epidemiology, National Public Health Institute, Helsinki, Finland
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8583
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Li N, Mattoo AK. Deletion of the carboxyl-terminal region of 1-aminocyclopropane-1-carboxylic acid synthase, a key protein in the biosynthesis of ethylene, results in catalytically hyperactive, monomeric enzyme. J Biol Chem 1994; 269:6908-17. [PMID: 8120053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
1-Aminocyclopropane-1-carboxylic acid (ACC) synthase is a key enzyme regulating biosynthesis of the plant hormone ethylene. The expression of an enzymatically active, wound-inducible tomato (Lycopersicon esculentum L. cv Pik-Red) ACC synthase (485 amino acids long) in a heterologous Escherichia coli system allowed us to study the importance of hypervariable COOH terminus in enzymatic activity and protein conformation. We constructed several deletion mutants of the gene, expressed these in E. coli, purified the protein products to apparent homogeneity, and analyzed both conformation and enzyme kinetic parameters of the wild-type and truncated ACC syntheses. Deletion of the COOH terminus through Arg429 results in complete inactivation of the enzyme. Deletion of 46-52 amino acids from the COOH terminus results in an enzyme that has nine times higher affinity for the substrate S-adenosylmethionine than the wild-type enzyme. The highly efficient, truncated ACC synthase was found to be a monomer of 52 +/- 1.8 kDa as determined by gel filtration, whereas the wild-type ACC synthase, analyzed under similar conditions, is a dimer. These results demonstrate that the non-conserved COOH terminus of ACC synthase affects its enzymatic function as well as dimerization.
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Affiliation(s)
- N Li
- Plant Molecular Biology Laboratory, United States Department of Agriculture-Beltsville Agricultural Research Center (West), Maryland 20705-2350
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8584
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el-Jammal A, Howell PL, Turner MA, Li N, Templeton DM. Copper complexation by 3-hydroxypyridin-4-one iron chelators: structural and iron competition studies. J Med Chem 1994; 37:461-6. [PMID: 7509878 DOI: 10.1021/jm00030a005] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Clinical trials of 1,2-dimethyl-3-hydroxypyridine-4-one (1) as an orally available iron chelator are presently underway in several centers. Discrepant reports of toxicity in human and animal studies have stimulated debate on the role of iron status and the availability of iron for chelation relative to other essential elements like copper in determining the clinical effects of 1. Therefore, we investigated the ability of 1, its 1,2-diethyl analog 2, and their iron chelates to complex copper. Both compounds formed tetracoordinate 2:1 Cu(II) complexes which X-ray structure analysis showed to be planar and coordinated through the oxygen atoms of the hydroxy ketone functionality. Potentiometric analysis revealed that these complexes dominated at physiological pH, although between pH 6 and 7 approximately equal amounts of the mono and bis complexes of Cu with 1 were present at equilibrium. Comparing the stepwise formation constants deduced from the stability constants of these complexes (log beta 2 = 21.7 +/- 0.8 (1) and 20.2 +/- 2.0 (2)) with those of their Fe(III) complexes (Motekaitis,R.J.;Martell,A.E.Inorg.Chim.Acta 1991, 183,71-80) leads to a prediction of insignificant copper complexation when equimolar iron is present and dissociation products are thermodynamically unimportant. However, displacement of Fe3+ occurred from both complexes with stoichiometric amounts of Cu2+, implicating the participation of metal hydrolysis products in the equilibria. We conclude that Cu(II) complexes of the 3-hydroxypyridin-4-one chelators are stable under physiological conditions and that copper can effect displacement of iron by these agents under circumstances where hydrolysis of the metals is important.
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Affiliation(s)
- A el-Jammal
- Department of Clinical Biochemistry, University of Toronto, Canada
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8585
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Li N, Hashimoto Y, Ezaki T. Determination of 16S ribosomal RNA sequences of all members of the genus Peptostreptococcus and their phylogenetic position. FEMS Microbiol Lett 1994; 116:1-5. [PMID: 8132148 DOI: 10.1111/j.1574-6968.1994.tb06666.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A comparative analysis of 16S ribosomal RNA sequences of all Peptostreptococcus species revealed that most members of the genus Peptostreptococcus should be divided into many different genera. The relationship between clostridia and peptostreptococci was analysed to find the phylogenetic position of peptostreptococci.
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Affiliation(s)
- N Li
- Department of Microbiology, Gifu University, School of Medicine, Japan
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8586
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Li N, Shen LH, Zhu QF. [Overexpression of c-erbB-2 proto-oncogene product in chondrosarcomas]. Zhonghua Bing Li Xue Za Zhi 1994; 23:37-9. [PMID: 7913884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The c-erbB-2 proto-oncogene plays an important role in the regulation of cellular proliferation and differentiation. Overexpression of c-erbB-2 proto-oncogene product in 40 cases of chondrosarcomas was investigated using ABC immunoperoxidase method. Overexpression of c-erbB-2 product was present in 36/40 (90%) chondrosarcomas and in 1/9 (11%) benign cartilage tumors. Normal cartilage tissue gave negative results. These findings indicate that c-erbB-2 proto-oncogene product has practical value in diagnosing chondrosarcomas. c-erbB-2 positive grading showed a significant inverse correlation with the histopathological grading. Chondrosarcomas with high histological grade and poor differentiation showed a bias toward a decline in expression of c-erbB-2 product. The c-erbB-2 proto-oncogene product may be used as a differentiation marker.
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Affiliation(s)
- N Li
- Department of Pathology, 309th Hospital
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8587
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Ezaki T, Li N, Hashimoto Y, Miura H, Yamamoto H. 16S ribosomal DNA sequences of anaerobic cocci and proposal of Ruminococcus hansenii comb. nov. and Ruminococcus productus comb. nov. Int J Syst Bacteriol 1994; 44:130-6. [PMID: 8123556 DOI: 10.1099/00207713-44-1-130] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The 16S ribosomal DNA sequences of representative members of the family Peptococcaceae were determined. The members of the family examined were divided into the following four phylogenetic groups: Peptococcus niger ATCC 27731T (T = type strain), the Sarcina-Peptostreptococcus anaerobius group, the ruminococcus-coprococcus group, and the peptostreptococcus group. Peptococcus niger, the type species of the family, was not related to other members of the family. Peptostreptococcus anaerobius ATCC 27337T, the type strain of the type species of the genus Peptostreptococcus, was closely related to Clostridium sordellii NCIB 10717T (level of sequence similarity, 85%). Sarcina ventriculi GIFU 7886, a spore-forming anaerobic gram-positive coccus, clustered with Clostridium perfringens ATCC 13124T at a similarity value of 91%. Members of the Sarcina-Peptostreptococcus anaerobius group clustered with clostridia at similarity values ranging from 85 to 91%. The type strains of Peptostreptococcus prevotii, Peptostreptococcus asaccharolyticus, Peptostreptococcus micros, and Peptostreptococcus magnus clustered at levels of sequence homology of 84 to 93%. This cluster was not included in the Peptococcus niger group or the Peptostreptococcus anaerobius group. Thus, these members of the genus Peptostreptococcus should be separated from the other members of the genus and also from members of the family Peptococcaceae. The sequence of Peptostreptococcus productus ATCC 27340T was different from the sequences of Peptostreptococcus anaerobius and Peptococcus niger. The sequence of Streptococcus hansenii ATCC 27752T, a strictly anaerobic strain, was different from the sequences of other streptococci; this strain clustered with Peptostreptococcus productus, coprococci, and ruminococci. Several phenotypic characteristics of Streptococcus hansenii ATCC 27752T were similar to characteristics of ruminococci.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- T Ezaki
- Department of Microbiology, Gifu University School of Medicine, Japan
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8588
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Abstract
OBJECTIVES The purpose of this study was to investigate a nosocomial outbreak of hepatitis A that occurred in the burn treatment center of a referral hospital. METHODS Retrospective cohort and case-control studies were performed to determine acquisition rates and risk factors for transmission. Adjusted infection rates were calculated by week of exposure. A case-control study was conducted to determine potential mechanisms for nosocomial acquisition. Recently infected health care workers were defined as case patients; exposed, serosusceptible health care workers without infection served as controls. RESULTS The outbreak of hepatitis A affected 11 health care workers and 1 other burn patient (1 secondary patient case). All 11 health care workers became ill after the admission of a man and his 8-month-old son who developed hepatitis A while in the hospital. The cumulative incidence risk ratio was elevated for health care workers caring for either the infant or the father during the same week of exposure. The case-control study implicated the behavior of eating on the hospital ward as the single most important risk factor for infection. CONCLUSION Inadequate hand-washing and subsequent oral contamination appear responsible for the outbreak. Hospitals may witness other institutional outbreaks if health care workers regularly eat on the wards.
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Affiliation(s)
- B N Doebbeling
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242-1081
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8589
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Pittet D, Li N, Wenzel RP. Association of secondary and polymicrobial nosocomial bloodstream infections with higher mortality. Eur J Clin Microbiol Infect Dis 1993; 12:813-9. [PMID: 8112351 DOI: 10.1007/bf02000400] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The objective of this study was to characterize microbiological factors independently associated with higher mortality rates following nosocomial bloodstream infection. All patients admitted to the University of Iowa Hospitals and Clinics between 1 July 1989 and 30 June 1990 who developed a nosocomial bloodstream infection were included. The crude in-house mortality for the 364 patients with nosocomial bloodstream infections was 33%. These deaths accounted for 25% of all in-hospital deaths. Significant risk factors for death from bloodstream infection included diagnoses of cancers and diseases of the cardiovascular and respiratory systems (p < 0.01). Neither previous surgery nor neutropenia was associated with higher mortality rates. Whereas the crude mortality rates associated with gram-negative (33%) and gram-positive (31%) bloodstream infections were similar, that associated with fungemia was higher (54%, p < 0.02). The mortality associated with secondary bloodstream infections (46%) was higher than that associated with primary bloodstream infections (28%, p < 0.001). Furthermore, polymicrobial infections had a worse prognosis than infections from which a single pathogen was isolated (p < 0.05). A multivariate, logistic regression model identified four variables that independently predicted mortality (p = 0.025): age (OR 1.01 per year; CI95 1.00-1.02); cancer (OR 2.35, CI95 1.26-4.37) or diseases of the cardiovascular or respiratory systems (OR 2.20, CI95 1.04-4.67); polymicrobial infection (OR 2.34; CI95 1.21-4.53); and secondary bloodstream infection (OR 2.46; CI95 1.50-4.02). The last variable was the strongest independent predictor. Our study demonstrates the importance of microbiological factors in the outcome of nosocomial bloodstream infections.
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Affiliation(s)
- D Pittet
- Department of Internal Medicine, Hôpital Cantonal Universitaire de Genève, Switzerland
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8590
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Pendergast AM, Quilliam LA, Cripe LD, Bassing CH, Dai Z, Li N, Batzer A, Rabun KM, Der CJ, Schlessinger J. BCR-ABL-induced oncogenesis is mediated by direct interaction with the SH2 domain of the GRB-2 adaptor protein. Cell 1993; 75:175-85. [PMID: 8402896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BCR-ABL is a chimeric oncoprotein that exhibits deregulated tyrosine kinase activity and is implicated in the pathogenesis of Philadelphia chromosome (Ph1)-positive human leukemias. Sequences within the first exon of BCR are required to activate the transforming potential of BCR-ABL. The SH2/SH3 domain-containing GRB-2 protein links tyrosine kinases to Ras signaling. We demonstrate that BCR-ABL exists in a complex with GRB-2 in vivo. Binding of GRB-2 to BCR-ABL is mediated by the direct interaction of the GRB-2 SH2 domain with a phosphorylated tyrosine, Y177, within the BCR first exon. The BCR-ABL-GRB-2 interaction is required for activation of the Ras signaling pathway. Mutation of Y177 to phenylalanine (Y177F) abolishes GRB-2 binding and abrogates BCR-ABL-induced Ras activation. The BCR-ABL (Y177F) mutant is unable to transform primary bone marrow cultures and is impaired in its ability to transform Rat1 fibroblasts. These findings implicate activation of Ras function as an important component in BCR-ABL-mediated transformation and demonstrate that GRB-2 not only functions in normal development and mitogenesis but also plays a role in oncogenesis.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Amino Acid Sequence
- Animals
- Binding Sites
- Cell Line
- Cell Transformation, Neoplastic/genetics
- Exons
- Fusion Proteins, bcr-abl/metabolism
- GRB2 Adaptor Protein
- Genes, abl
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive
- Moths
- Mutagenesis, Site-Directed
- Phenylalanine
- Point Mutation
- Promoter Regions, Genetic
- Protein Binding
- Protein-Tyrosine Kinases/metabolism
- Proteins/metabolism
- Proto-Oncogene Proteins/biosynthesis
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins c-bcr
- Proto-Oncogenes
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/metabolism
- Transcription, Genetic
- Tumor Cells, Cultured
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Affiliation(s)
- A M Pendergast
- Department of Pharmacology, Duke University Medical Center, Durham, North Carolina 27710
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8591
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Zhou WG, Wang TF, Xue Y, Li N, Wu JG, Yu YS. Chronic tonsillitis and IgA nephropathy. Chin Med J (Engl) 1993; 106:770-2. [PMID: 8033611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The authors studied the effect of tonsillectomy for IgA nephropathy and the relationship between chronic tonsillitis and IgA nephropathy. Forty-five patients with IgA nephropathy were treated by tonsillectomy in our department. The effective rate of hematuria type IgA nephropathy was 86.2% and that of non-hematuria type 62.5%. We also determined the immunoglobulin composition of the tonsilla tissue in 18 IgA nephropathy patients and compared it with that of 18 chronic tonsillitis patients. The immunoglobin level of the IgA nephropathy group was higher than that of the contrast group, indicating that the disorder of tonsilla immunity may be one of the pathogenic factors for IgA nephropathy. Since no specific method has been available for the treatment of IgA nephropathy, we use tonsillectomy as an effective procedure.
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Affiliation(s)
- W G Zhou
- Department of Otorhinolaryngology, Jinling Hospital, Nanjing
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8592
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Li N, Mao B. [Vascular malformation of posterior cerebral artery in supertentorium]. Hua Xi Yi Ke Da Xue Xue Bao 1993; 24:331-4. [PMID: 8288213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Seventeen cases of vascular malformation of posterior cerebral artery in supertentorium from 1973 to 1991 are reported. These patients accounted for 8.8% of the total supertentorial vascular malformations during the same period. Their ages ranged from ten to forty-eight years with an average of thirty-one years. The vascular malformation was located in the occipital lobe or under the temporal lobe. Its main blood supply was from the basilar artery. Headache and hemorrhage were common clinical manifestations. Some cases had a defect of the visual field. Vertebral angiography is necessary for diagnosis of this disease. All the seventeen cases were operated without any death. The operative approach and experience in seeking for the vascular malformation during the operation are discussed.
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8593
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Hashimoto Y, Li N, Yokoyama H, Ezaki T. Complete nucleotide sequence and molecular characterization of ViaB region encoding Vi antigen in Salmonella typhi. J Bacteriol 1993; 175:4456-65. [PMID: 8331073 PMCID: PMC204886 DOI: 10.1128/jb.175.14.4456-4465.1993] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Plasmid pGBM124, which contains a 14-kb Salmonella typhi chromosomal DNA fragment capable of producing the Vi antigen in Escherichia coli HB101 and ViaB-deleted S. typhi GIFU 10007-3, was studied. We determined the complete nucleotide sequence of this fragment and found 11 open reading frames. Mutagenesis, subcloning, and complementation analysis showed that three genes (vipA, vipB, and vipC) are involved in biosynthesis of the Vi polysaccharide. The putative primary amino acid sequence suggests that both vipA and vipB encode the NAD- or NADP-dependent enzymes to synthesize the nucleotide sugar for the Vi polysaccharide. Five genes (vexA, vexB, vexC, vexD, and vexE) may be involved in translocation of the Vi polysaccharide. Proteins VexA, VexB, VexC, and VexD had moderate similarities to components of group II capsule transporters, and the VexC protein had a putative ATP-binding site. These data indicate that the transport system for the Vi polysaccharide belongs to the ATP-binding cassette transporters. By using the isogenic Vi+ and Vi- strains constructed in this study, we reconfirmed that the Vi antigen is necessary for the serum resistance of S. typhi.
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MESH Headings
- Agglutination Tests
- Amino Acid Sequence
- Antigens, Bacterial/analysis
- Antigens, Bacterial/biosynthesis
- Antigens, Bacterial/genetics
- Autoradiography
- Base Sequence
- Chromosomes, Bacterial
- Cloning, Molecular
- DNA, Bacterial/genetics
- DNA, Bacterial/metabolism
- Escherichia coli/genetics
- Genes, Bacterial
- Humans
- Immunodiffusion
- Methionine/metabolism
- Molecular Sequence Data
- Multigene Family
- Mutagenesis, Insertional
- Open Reading Frames
- Polysaccharides, Bacterial
- Protein Structure, Secondary
- Recombinant Fusion Proteins/analysis
- Recombinant Fusion Proteins/biosynthesis
- Restriction Mapping
- Salmonella typhi/genetics
- Salmonella typhi/metabolism
- Sequence Deletion
- Sequence Homology, Amino Acid
- Sulfur Radioisotopes
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Affiliation(s)
- Y Hashimoto
- Department of Microbiology, Gifu University School of Medicine, Japan
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8594
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Sawamura M, Li N, Nara Y, Yamori Y. Proliferative effect of mevalonate metabolites other than isoprenoids on cultured vascular smooth muscle cells. Clin Exp Pharmacol Physiol 1993; 20:509-14. [PMID: 8403532 DOI: 10.1111/j.1440-1681.1993.tb01733.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
1. Recent investigations revealed that isoprenoid compounds serve as key substances for cellular proliferation through post-translational modification. Previously we reported that tissues of spontaneously hypertensive rats (SHR) had a lower activity of isoprenoid biosynthesis when compared with the normotensive control rat (WKY). However, cultured vascular smooth muscle cells (VSMC) of SHR showed an enhanced growth rate. These findings led us to investigate further the effect of isoprenoid compounds on VSMC proliferation. 2. When the cells of WKY were stimulated with 5% fetal calf serum (FCS) in the presence of lovastatin, [3H]-thymidine incorporation decreased in a dose-dependent manner and was completely inhibited at 30 mumol/L. Exogenously added mevalonate showed a protective effect against lovastatin (81% protection at 0.1 mumol/L). 3. Fluoromevalonate (Fmev), an inhibitor of mevalonate-PP decarboxylase which converts mevalonate-PP into isoprenoids, showed a dual inhibitory effect. DNA synthesis was partially inhibited at 0.01-1 mumol/L, however at 10 mumol/L there was no detectable inhibition. The inhibitory effect was again observed at concentrations over 10 mumol/L. 4. In the presence of lovastatin and Fmev to block both HMG CoA reductase and mevalonate-PP decarboxylase, exogenous mevalonate dose dependently stimulated [3H]-thymidine incorporation induced by FCS. 5. These data suggest the positive effect of the initial mevalonate derivatives other than isoprenoid compounds on the proliferation of VSMC.
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MESH Headings
- Animals
- Carboxy-Lyases/antagonists & inhibitors
- Cell Division/drug effects
- Cells, Cultured
- DNA/biosynthesis
- Dose-Response Relationship, Drug
- Hydroxymethylglutaryl-CoA Reductase Inhibitors
- Lovastatin/pharmacology
- Mevalonic Acid/analogs & derivatives
- Mevalonic Acid/metabolism
- Mevalonic Acid/pharmacology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Protein Biosynthesis/drug effects
- Rats
- Rats, Inbred SHR
- Rats, Inbred WKY
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Affiliation(s)
- M Sawamura
- Graduate School of Human and Environmental Studies, Kyoto University, Japan
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8595
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Simon M, Dodson G, Rubin G, Olivier J, Egan S, Giddings B, Brooks M, Buday L, Sizeland A, Weinberg R, Rozakis-Adcock M, Fernley R, Wade J, Pawson T, Bowtell D, Li N, Gale N, Kaplan S, Lowestein E, Schlessinger J, Bar-Sagi D, Buday L, Downward J, Chardin P. Tyrosine kinases to Ras. Trends Cell Biol 1993. [DOI: 10.1016/0962-8924(93)90117-j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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8596
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Skolnik EY, Batzer A, Li N, Lee CH, Lowenstein E, Mohammadi M, Margolis B, Schlessinger J. The function of GRB2 in linking the insulin receptor to Ras signaling pathways. Science 1993; 260:1953-5. [PMID: 8316835 DOI: 10.1126/science.8316835] [Citation(s) in RCA: 477] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Insulin-induced activation of extracellular signal-regulated kinases [ERKs, also known as mitogen-activated protein (MAP) kinases] is mediated by Ras. Insulin activates Ras primarily by increasing the rate of guanine nucleotide-releasing activity. Here, we show that insulin-induced activation of ERKs was enhanced by stable overexpression of growth factor receptor-bound protein 2 (GRB2) but not by overexpression of GRB2 proteins with point mutations in the Src homology 2 and 3 domains. Moreover, a dominant negative form of Ras (with Ser17 substituted with Asn) blocked insulin-induced activation of ERKs in cells that overexpressed GRB2. GRB2 overexpression led to increased formation of a complex between the guanine nucleotide-releasing factor Sos (the product of the mammalian homolog of son of sevenless gene) and GRB2. In response to insulin stimulation, this complex bound to tyrosine-phosphorylated IRS-1 (insulin receptor substrate-1) and Shc. In contrast to the activated epidermal growth factor receptor that binds the GRB2-Sos complex directly, activation of the insulin receptor results in the interaction of GRB2-Sos with IRS-1 and Shc, thus linking the insulin receptor to Ras signaling pathways.
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Affiliation(s)
- E Y Skolnik
- Department of Pharmacology, New York University Medical Center, NY 10016
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8597
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Li N. [The phytohemagglutinins and soybean agglutinin in diagnosis of endometrial adenocarcinoma]. Zhonghua Fu Chan Ke Za Zhi 1993; 28:349-50, 381. [PMID: 8243160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The distribution of PHA and SBA receptors was studied by ABC immunoperoxidase method in 30 cases of endometrial adenocarcinoma (EA), 10 cases of normal endometrium (NE) and 20 cases of cystic glandular hyperplastic endometrium (CGH). The results showed that the positive rate of PHA and SBA in EA was 46.67% and 73.33% respectively, but negative and low in NE and CGH (P < 0.05). PHA and SBA showed a progressive rising tendency along with the changes of NE to CGH and EA (P < 0.01). It is suggested that both PHA and SBA may be used as differentiated markers in EA and may be helpful in clinical diagnosis.
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Affiliation(s)
- N Li
- PLA 309 Hospital, Beijing
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8598
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Li N, Batzer A, Daly R, Yajnik V, Skolnik E, Chardin P, Bar-Sagi D, Margolis B, Schlessinger J. Guanine-nucleotide-releasing factor hSos1 binds to Grb2 and links receptor tyrosine kinases to Ras signalling. Nature 1993; 363:85-8. [PMID: 8479541 DOI: 10.1038/363085a0] [Citation(s) in RCA: 801] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Many of the actions of receptor tyrosine kinases are mediated by the protein Ras, including the activation of various downstream serine/threonine kinases and the stimulation of growth and differentiation. The human protein Grb2 binds to ligand-activated growth factor receptors and downstream effector proteins through its Src-homology (SH) domains SH2 and SH3, respectively, and like its homologue from Caenorhabditis elegans, Sem-5, apparently forms part of a highly conserved pathway by which these receptors can control Ras activity. Here we show that the SH3 domains of Grb2 bind to the carboxy-terminal part of hSos1, the human homologue of the Drosophila guanine-nucleotide-releasing factor for Ras, which is essential for control of Ras activity by epidermal growth factor receptor and sevenless. Moreover, a synthetic 10-amino-acid peptide containing the sequence PPVPPR specifically blocks the interaction. These results indicate that the Grb2/hSos1 complex couples activated EGF receptor to Ras signalling.
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Affiliation(s)
- N Li
- New York University Medical Center, Department of Pharmacology, New York 10016
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8599
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Pittet D, Thiévent B, Wenzel RP, Li N, Gurman G, Suter PM. Importance of pre-existing co-morbidities for prognosis of septicemia in critically ill patients. Intensive Care Med 1993; 19:265-72. [PMID: 8408935 DOI: 10.1007/bf01690546] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE To determine admission characteristics associated with the outcome of septicemia in critically ill patients and more specifically assess the prognostic value of pre-existing co-morbidities. DESIGN 5 year-retrospective cohort study. SETTING Surgical Intensive Care Unit (ICU-20 beds) in a 1600 bed-tertiary care center. PATIENTS Among 5457 patients admitted to the ICU between 1984 and 1988, 176 (3.2%) met prospectively-defined criteria for blood culture-proven septicemia (8.77 per 1000 patient-days). Overall septicemic patients had a 5-fold increased risk of death compared to non-septicemic patients (relative risk 5.03, 95% confidence intervals 4.17-6.07, p < 0.0001), and this estimate persisted after stratification according to age, sex, primary diagnosis and conditions of admission to the ICU (emergency/elective). RESULTS Prognostic factors recorded on admission to ICU that were associated with mortality from septicemia among 173 patients were older age, higher admission Apache II score, gastrointestinal surgery, ultimately and rapidly fatal diseases and the number of co-morbidities in addition to the principal diagnosis (active smoking, alcohol abuse, non-cured malignancy, diabetes mellitus, splenectomy, recent antibiotic therapy, major surgery, or major cardiac event). In the multivariate analysis with logistic regression procedures, Apache II and co-morbidities were identified as the two independent predictors of mortality. CONCLUSIONS Pre-existing co-morbidities assessed at the admission to the ICU significantly improved the prediction of mortality from septicemia compared to Apache II score alone.
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Affiliation(s)
- D Pittet
- Department of Internal Medicine, University Hospital of Geneva, Switzerland
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8600
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Cheng XZ, Liu RL, Zhou WQ, Zhao XG, Li N, Zhao GF, Hou JP, Wang RF, Qiao YF. [Measurement of the single muscle fiber action potentials and jitter value in tibialis anterior muscles of rabbits in situ]. Sheng Li Xue Bao 1993; 45:124-9. [PMID: 8356467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
With a home-made jitter data processing board and microcomputer for recording extracellular single fiber action potential (SF-AP), variations of the time intervals of the SF-AP pairs, or the jitters, from two adjacent muscle fibers in the unique motor unit in tibialis' anterior in response to repeated stimuli were measured. The jitter distribution of 936 recorded from 7 rabbits was positively showed with a percentile value of P75-P25 of 54.99-14.61 microseconds. The data suggested that the lower limit was smaller than that of skeletal muscles in normal human and that there exists also some differences in the jitter values of SFEMG between human and rabbit muscles.
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Affiliation(s)
- X Z Cheng
- Department of Physiology, Weifang Medical College
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