Numerical simulation of oil-droplet cleavage by surfactant

We present numerical computations of the deformation of an oil-droplet under the influence of a surface tension gradient generated by the surfactant released at the poles (the Greenspan experiment). We find this deformation to be very small under the pure surface tension gradient. To explain the large deformation of oil droplets observed in Greenspan's experiments, we propose the existence of a phoretic force generated by the concentration gradient of the surfactant. We show that this hypothesis successfully explains the available experimental data and we propose some further tests.

[Etoposide combination chemotherapy for malignant lymphoma: a report of 91 cases]

From August 1984 to August 1994 ninety-one caese of malignant lymphoma (NHL 84 casese, HD 7 cases) were treated with Etoposide (VP-16) combinationn chemotherapy. In 70 evaluable patients, 18 achieved CR, 35 PR, total response rate was 75.7%, response time (RT) 1-79 months, medium response time (MRT) 9 months, survival time (ST) 2-79 months, medium survival time (MST) 12 months. The therapeutic efficacy was better than VP-16 alone. The major side effects were myelosuppression and gastrointestinal toxicity. In COPEP, CHEP, PEP and IEP regimens, best result was seen in COPEP (CTX + VCR + PYM + VP-16 + PDN), with a response rate of 93%. Authors suggest that COPEP protocol could be the first line treatment for patients with malignant lymphoma who did not tolerate anthracycline drugs and the second line treatment for anthracycline-resistant patients.

Probing the coenzyme and substrate binding events of CDP-D-glucose 4,6-dehydratase: mechanistic implications

NAD+-dependent nucleotidyl diphosphohexose 4,6-dehydratases which transform nucleotidyl diphosphohexoses into corresponding 4-keto-6-deoxy sugar derivatives are essential to the formation of all 6-deoxyhexoses. Studies of the CDP-D-glucose 4,6-dehydratase (Eod) from Yersinia had shown that this dimeric protein binds only 1 equiv of NAD+/mol of enzyme and, unlike other enzymes of the same class, displays a unique NAD+ requirement for full catalytic activity. Analysis of the primary sequence revealed an extended ADP-binding fold (GHTGFKG) which deviates from the common Rossman consensus (GXGXXG) and thus may have contributed to Eod's limited NAD+ affinity. In particular, the presence of His17 in the beta-turn region and that of Lys21 in a position typically occupied by a small hydrophobic residue may impose electronic or steric perturbations to this essential binding motif. To better understand the correlation between the binding properties and primary sequence, mutants (H17G and K21I) were constructed to provide enzymes containing an ADP binding region which more closely resembles the Rossman-type fold. Analysis of the cofactor and substrate binding characteristics of the wild-type and mutant enzymes helped define the presence of two binding sites for both CDP-d_glucose and NAD+ per enzyme molecule. While both mutants displayed enhanced NAD+ affinity, the H17G mutation resulted in an enzyme with slightly higher kcat and a 3-fold increase in catalytic efficiency (kcat/Km). The large anticooperativity found for NAD+ binding (K1=40.3 + or - 0.4 nM, K2=539.8 + or - 4.8 nM) may explain why the cofactor binding sites of wild-type Eod are only half-occupied. Further examination also revealed the purified Eod to contain sequestered NADH and that the affinity of Eod for NADH(K1=0.21 + or - 0.01 nM, K2= 7.46 + or -0.25 nM) is much higher than that for NAD+. Thus, it is possible that Eod's half-site saturation of NAD+ per enzyme dimer may also be attributed to a significant portion of the cofactor binding sites being occupied by NADH. Interestingly, the sequestered NADH is released upon binding with CDP-D-glucose. These results implicate a new kinetic mechanism for Eod catalysis.

Temporal patterns of aflatoxin-albumin adducts in hepatitis B surface antigen-positive and antigen-negative residents of Daxin, Qidong County, People's Republic of China

Molecular epidemiological studies of populations at high risk for liver cancer have shown that hepatitis B virus (HBV) and aflatoxin B1 (AFB1) exposure are two major risk factors for this disease. These etiological agents, combined with nutritional deficiencies, are important for the initiation and promotion of liver cancer in various parts of the world. In Qidong, People's Republic of China, liver cancer accounts for 10% of all adult deaths, and both HBV and AFB1 exposures are common. To study temporal and possible chemical-viral interactions in people, serum samples were collected during a longitudinal study designed to measure aflatoxin molecular biomarkers in residents of Daxin Township, Qidong City, People's Republic of China. In this study, the temporal modulation of aflatoxin adduct formation with albumin over multiple lifetimes of serum albumin was examined in both HBV-positive and HBV-negative people in two periods: September-December 1993 (wave 1) and June-September 1994 (wave 2). During the 12-week monitoring period of wave 1, 120 individuals (balanced by gender and HBV status) provided a total of 792 blood samples. AFB1-albumin adducts were detected in all but one of the serum samples. The range of binding detected by RIA in the Daxin population was 0.17-4.39 pmol AFB11/mg albumin with an overall mean +/- SD of 1.51 +/- 0.21 pmol AFB11/mg albumin. The mean +/- SD for weeks 0, 2, 4, 6, 8, 10 and 12 of wave 1 were 1.21 +/- 0.41, 1.58 +/- 0.70, 1.36 +/- 0.52, 1.71 +/- 0.44, 1.18 +/- 0.60, 2.00 +/- 0.59, and 1.68 +/- 0.34 pmol AFB1/mg albumin, respectively. During wave 2, 103 individuals from wave 1 provided a total of 396 blood samples collected monthly over wave 2, with mean +/- SD aflatoxin-albumin adduct levels of 1.19 +/- 0.37, 0.85 +/- 0.45, 0.89 +/- 0.28, and 0.61 +/- 0.15 pmol AFB1/mg albumin. Using linear regression models, the mean aflatoxin-albumin adduct levels increased (P < 0.05) during the 12 weeks of wave 1 and decreased (P < 0.05) over the 4 months of wave 2. Neither HBV surface antigen status nor gender modified either the baseline mean or the temporal trend. High-performance liquid chromatography confirmation was done on a subset of serum samples, and the results show an excellent association between the immunoassay data and high-performance liquid chromatography. Taken together, these data demonstrate that AFB1-albumin is a sensitive and specific biomarker for assessing exposure to this carcinogen in the population in Qidong.

[Alteration of mRNA transcripts of rat Sertoli cell secreted proteins and Leydig cell LH/CG-R protein following glycosides of Tripterigium Wilfordii Hook administration]

Our studies were undertaken to assess the male antifertility mechanism of the total glycosides extracted from Tripterigium Wilfordii Hook. f. (GTW). In experimental group I, GTW was given by gastric gavage at a dose of 30 mg/kg per day for 35 days. In experimental group I, GTW was given in the same way at a dose of 10 mg/kg per day for 49 days. The transcripts level analysis indicated that in all the experimental groups ABP, SGP-2 and LH/CG-R mRNA were increased. Two ABP and two LH/CG-R mRNA transcripts with respective molecular sizes of 1.7 kb, 2.3 kb and 1.2 kb, 4.4 kb were identified. ABP and LH/ CG-R mRNA with 1.7 kb and 1.2 kb increased, while those with 2.3 and 4.4 kb remained unchanged. In addition, the changes of different proteins at the mRNA level were shown to be GTW dose-dependent. The morphological features of germ cell degeneration and appearance of germ cells in tubular lumen suggest that the increases in transcripts level of three proteins in testis may not be directly associated with the effect of GTW. The question whether GTW interfere with the function of sertoli cells and leydig cells would be study.

[The postnatal changes of follicle-stimulating hormone receptor mRNA level in rat testis]

It was found in this study that the follicle-stimulating hormone receptor (FSHR) mRNA levels varied between days 2 and 60. The FSHR mRNA rised slightly in the neonatal rat testis and then declined. In the prepuberty the content of FSHR mRNA remained at a Constant level. During the puberty the FSHR mRNA increased to its highest level on days 25 and finally it rised again after days 40.

Intrapancreatic cholecystokinin mediates vagally stimulated exocrine secretion from the rat pancreas

Although cholecystokinin is localized within neuronal fibres of the pancreas, a physiological role for intrapancreatic cholecystokinin has not been identified. The strategy of this study was to elicit pure vagal stimulation electrically, and to use specific receptor antagonists to identify the mediators of exocrine pancreatic secretion. We conclude that vagal stimulation of the rat pancreas involves ganglionic neurotransmission and release of acetylcholine and cholecystokinin from intrapancreatic, postganglionic fibres. To our knowledge, this is the first study to demonstrate a physiological role for intrapancreatic cholecystokinin.

Human alpha-tocopherol transfer protein: gene structure and mutations in familial vitamin E deficiency

Familial vitamin E deficiency (AVED) causes ataxia and peripheral neuropathy that resembles Friedreich's ataxia. AVED is thought to be caused by a defect in the transport of vitamin E in liver cells, which is the probable function of alpha-tocopherol transfer protein (alphaTTP). We have cloned the cDNA and several genomic phage clones covering the entire human alphaTTP gene and determined the junctions between the five exons and four introns that composed the gene for human alphaTTP. Three mutations in three unrelated North American families with AVED were identified. Two mutations, 485delT and 513insTT, cause a frame shift and a premature stop codon and the third mutation 574G-->A would substitute Arg192 to His in alphaTTP. The 2 patients with a severe form of AVED were homozygous with 485delT and 513insTT, respectively, while the patient with a mild form of the disease was compound heterozygous with 513insTT and 574G-->A. These findings have identified the underlying genetic defect in AVED and have confirmed the role of alphaTTP in AVED.

Pulsatile flow in the human left coronary artery bifurcation: average conditions

The localization of atherosclerosis in the coronary arteries may be governed by local hemodynamic features. In this study, the pulsatile hemodynamics of the left coronary artery bifurcation was numerically simulated using the spectral element method for realistic in vivo anatomic and physiologic conditions. The velocity profiles were found to be skewed in both the left anterior descending and the circumflex coronary arteries. Velocity skewing arose from the bifurcation as well as from the curvature of the artery over the myocardial surface. Arterial wall shear stress was significantly lower in the bifurcation region, including the side walls. The greatest oscillatory behavior was localized to the outer wall of the circumflex artery. The time-averaged mean wall shear stress varied from about 3 to 98 dynes/cm2 in the left coronary artery system. The highly localized distribution of low and oscillatory shear stress along the walls strongly correlates with the focal locations of atheroma in the human left coronary artery.

VH3-21 B cells escape from a state of tolerance in rheumatoid arthritis and secrete rheumatoid factor

BACKGROUND

Rheumatoid factor (RF) is a characteristic but not pathognomic feature in patients with rheumatoid arthritis (RA). It is unknown whether the repertoire of immunoglobulin genes utilized by RF+ B cells of RA patients is unique and whether RF+ B cells in normal individuals are silenced or deleted.

MATERIALS AND METHODS

Clonal B cell populations were established from the peripheral blood of normal donors (127 B cell clones), RA patients (113 RF- and 60 RF+ B cell clones) and patients with primary Sjögren's syndrome (82 RF- and 47 RF+ B cell clones) by coculturing with anti-CD3-stimulated T helper cell clones. The cross-reactivity pattern of antibodies secreted by the B cell clones was determined by ELISA on a panel of antigens. The molecular structure of the IgM heavy chains was characterized by VH family-specific RT-PCR and sequencing. VH elements which correlated with RF specificity were identified. The responsiveness of B cells expressing these VH elements to T helper cell signals was compared in normal individuals and RA patients.

RESULTS

The majority of RF+ B cells were monospecific when specificity was tested on five antigens. RF+ B cells expressed a significantly different repertoire of VH gene segments than RF- B cells. In particular, the VH3 gene segment V3-21 was not detected in B cell clones from normals but was the most frequent VH element in RF+ B cell clones from RA patients. Most of the V3-21 sequences were in germline configuration. The correlation between RF specificity and V3-21 gene segment usage was maintained in patients with Sjögren's syndrome. V3-21 transcripts were present in peripheral blood B cells from normal individuals. VH3-21+ B cells from RA patients but not from normal donors were responsive to preactivated T helper cells. Stimulation with a bacterial superantigen could overcome the nonresponsiveness of V3-21+ B cells in normal donors and induce the secretion of RF.

CONCLUSIONS

RF production is correlated with the usage of the V3-21 gene segment in two distinct RF+ diseases. In patients with these diseases, V3-21+ B cells secrete antibodies with RF activity in response to activated T helper cells. V3-21+ B cells remain in a state of nonresponsiveness in normal individuals that can be broken by superantigen stimulation. The germline configuration of VH3-21+ RF+ immunoglobulins in RA patients suggests that the loss of tolerance is not an antigen-driven process.

Torulopsis glabrata: azole susceptibilities by microdilution colorimetric and macrodilution broth assays

Fluconazole and itraconazole MICs were determined by both the standard macrodilution method of the National Committee for Clinical Laboratory Standards and a colorimetric broth microdilution method for 140 isolates of Torulopsis (Candida) glabrata obtained over a 15-year period. Using the method of the National Committee for Clinical Laboratory Standards the MICs at which 90% of isolates are inhibited (MIC50) for all isolates were 32 and 1.6 micrograms/ml for fluconazole and itraconazole, respectively. For fluconazole, the MIC90 rose from 16 to > 64 micrograms/ml when the MIC90s for isolates collected from July 1980 to June 1991 were compared with those for isolates collected from July 1991 to March 1995. For itraconazole, the MIC90s for isolates from the same time periods were 0.8 and 3.2 micrograms/ml, respectively. Although for isolates from some non-human immunodeficiency virus-infected patients the MICs rose, most of the high MICs were found for isolates from human immunodeficiency virus-infected patients who had been extensively treated with azole drugs for thrush. The colorimetric method yielded endpoints that were more definitive; concordances within 2 dilutions for the two methods were 87% for fluconazole and 86% for itraconazole.

Controlling cancerous pain with analgesic powder for cancers

Analgesic powder for cancers, composed of more than 20 Chinese drugs, was applied externally to 91 patients with various kinds of cancers for management of cancerous pain. The results showed that it was remarkably effective in 42 cases, fairly effective in 22, effective in 22, and ineffective in 5, the total effective rate being 94.51%. Animal experiments indicated that the pain threshold was evidently higher in mice treated with this powder on the site of femoral artery of the hind limbs than that of the controls without application of this powder.

High-yield affinity alkylation of the atrial natriuretic factor receptor binding site

To facilitate characterization of the atrial natriuretic factor (ANF) receptor, we have developed an affinity labeling procedure, stepwise affinity labeling, which allows specific labeling of ANF binding sites in adrenal plasma membranes at high yields. An iodoacetyl (IAc-), bromoacetyl (BrAc-), or maleimidobenzoyl group was attached to the amino-terminal alpha-amino group of the ANF(4-28) peptide, and the peptide derivatives were radioiodinated at Tyr-28 to obtain affinity reagents, N4alpha-IAc-[125I]ANF(4-28), N4alpha-BrAc-[125I]ANF(4-28), and N4alpha-(maleimidobenzoyl)-[125I]ANF(4-28). Receptor labeling was carried out in a stepwise fashion as follows: (1) Membranes were treated with p-chloromercuriobenzenesulfonic acid (PCMBS) or N-ethylmaleimide to block sulfhydryl groups; (2) the affinity reagent was allowed to bind to the receptor at 0 degrees C for 1 h; and (3) the membranes were washed to remove unbound reagent and were incubated at room temperature to effect alkylation reaction. Sodium dodecylsulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) followed by autoradiography revealed specific labeling of a 130-kDa ANF receptor. On the basis of 125I-radioactivity incorporated, the labeling yields were estimated to be 70%, 52%, and 21% for the reactions with IAc-[125I]ANF(4-28), BrAc-[125I]ANF(4-28), and (maleimidobenzoyl)-[125I]ANF(4-28), respectively. The efficiency of receptor labeling by the stepwise procedure using IAc-[125I]ANF(4-28) was 27-fold greater than that obtained by photoaffinity labeling using N3Bz-[125I]ANF(4-28) and 63-fold greater than that by direct cross-linking using disuccinimidylsuberate and [125I]ANF(4-28) under comparable conditions. Digestion of the membrane protein labeled with IAc-[125I]ANF(4-28) by BrCN, endoproteinase Glu-C, and endoproteinase Lys-C gave single radiolabeled bands with apparent masses of 40, 18, and 29 kDa, respectively. Reversed-phase HPLC separation of the digests also gave single major peaks. The confinement of the affinity label to one major fragment in each digest suggests that the cross-linking occurred at a single or a limited number of sites. The stepwise affinity labeling with the high cross-linking yield and specificity may be useful for analyzing the ANF receptor binding site structure.

[Genetic epidemiological studies on male lung cancer]

Data of nuclear families of 194 male proband with lung cancer and 176 controls were analyzed to study its genetic etiology in Xuanwei County of Yunnan Province. Results showed risk of lung cancer in the relatives (parents and siblings) of the proband was 1.78 times as of controls, with a statistically significant difference, and risks in parents and female relatives of the proband were 2.90 and 2.43 times as in controls, respectively, both with a statistically significant difference. Heritability of male lung cancer was 24.68%. It indicated genetic susceptibility to lung cancer in females was higher than that in males and played an important role in the etiology of lung cancer.

Induction of apoptosis of T cells by infecting mice with murine cytomegalovirus

Cytomegalovirus (CMV) is associated with several lymphocyte dysfunctions, but the precise mechanisms of the dysfunctions are still unclear. To elucidate the mechanisms, a cell cycle-DNA content analysis was performed on splenic T cells of murine CMV (MCMV)-infected BALB/c mice. T cells from mice infected with 3 x 10(3) PFU of MCMV contained a higher percentage of hypodiploid nuclei after 12 or 24 h of culture than those from naive mice. T cells from infected mice also contained a larger amount of fragmented DNA. Taken together, these results suggested that infection with MCMV induced the apoptotic cell death of T cells. This induction of apoptosis accounted for the dysfunction of lymphocytes, at least partially. Flow cytometric analysis showed that T cells as well as B cells from MCMV-infected mice expressed an augmented level of Fas antigen, an apoptosis-associated cell surface molecule, which might be the cause of the apoptosis of cells. T cells from MCMV-infected C57BL/6-lpr/lpr mice with mutations at the lpr/fas locus, however, also showed a substantial level of apoptosis, which was reproducibly lower than that seen in C57BL/6 mice. Therefore, it was suggested that the Fas-mediated pathway contributed to but was not sufficient for the induction of apoptosis and that mechanisms other than the Fas-associated pathway were also involved in the induction of apoptosis.

The expression of acetyl coenzyme A carboxylase is related to megakaryocyte maturation

We have previously demonstrated that de novo fatty acid synthesis predominantly occurs in later phases of megakaryocyte maturation. Therefore we have investigated the expression of fatty acid synthase (FAS) and acetyl coenzyme A carboxylase (ACC), key enzymes for fatty acid synthesis in megakaryocytes at different phases of maturation. Immature and mature megakaryocytes were isolated. Guinea pig-specific FAS and ACC cDNA probes were prepared by reverse transcriptase reaction-polymerase chain reaction (RT-PCR). The probes were used to assess the expression of mRNA for ACC and FAS by Northern blotting. The hybrids were quantitated by densitometry. Endogenous megakaryocyte ACC was quantitated by virtue of its biotin content by Western blotting with streptavidin and enhanced chemiluminescence (ECL). The ratio of ACC mRNA between mature and immature megakaryocytes was 2.43 +/- 0.86, and the ratio of FAS mRNA was 0.50 +/- 0.13 (mean +/- SD, n = 4). The ratio of endogenous ACC in mature and immature megakaryocytes was 1.96 +/- 0.62 (n = 6). The study showed that the FAS mRNA was expressed in all phases of megakaryocyte maturation. However, both mRNA for ACC and endogenous ACC were demonstrated primarily in mature megakaryocytes. Thus de novo fatty acid synthesis in megakaryocytes may depend on the expression of ACC in mature cells. The expression of ACC occurs during the terminal phases of megakaryocyte maturation and may be a marker of megakaryocyte maturity.

Effectiveness of Norplant implants through seven years: a large-scale study in China

The effectiveness of Norplant implants over a seven year period of continuous use was studied in a multicenter trial. Pregnancy rates were 0.4 per 100 in both year six and year seven. More than 3,600 women completed 6 years and more than 2,400 women completed 7 years. Pregnancy rates increased with weight (p < .05) and decreased with age, but in years 6 and 7 combined, the pregnancy rate neither reached nor exceeded 1 per 100 woman years in any 5 year age group or in any 10 kg weight group.

Flow in T-bifurcations: effect of the sharpness of the flow divider

The local geometry of a bifurcation has been hypothesized to be a potential geometrical risk factor for the development of atherosclerosis. While flow division and branch area ratios clearly affect the flow field, the importance of the flow divider shape is not as clear. A fast spectral element computational fluid mechanics (CFD) solver was used to simulate flow through 90 degrees T-bifurcations with three different flow divider shapes. Other factors, such as flow partition, area ratio, and bifurcation angle, were kept constant. A Reynolds number range of 15 to 350 was studied to bracket experimental results in the literature. The variation in the sharpness of the corners had a dramatic effect on both the flow field and wall shear stress distribution in the side branch, but little effect on the flow in the main tube. The magnitude of reverse velocities and wall shear stress in the side branch increased linearly over a physiological range of Reynolds number and corner shape. This paper verifies the accuracy and usefulness of spectral element CFD in studying three-dimensional hemodynamics.

Modeling chemoattractant-elicited relocalization of myosin filaments in Dictyostelium

Dictyostelium myosin is able to assemble into filaments that, when visualized under normal conditions, appear to be uniformly distributed throughout the cytoplasm. After stimulation by the chemoattractant cAMP, these filaments quickly diminish in the cellular medulla and accumulate in the cortex. A general hypothesis to explain the mechanism of this relocalization proposes that one or more of the chemical coefficients governing filament polymerization is precisely regulated by some sort of intracellular second messenger. To investigate this hypothesis we formulated a simple theoretical model of myosin polymerization and then used this model to analyze the resting state of the cell and various scenarios for initializing a transition to the activated state. In general, we found that the relocalization of filaments could be realized if a second messenger increased the elongation and (or) the nucleation coefficients for filament assembly in cortical ectoplasm and (or) if the messenger decreased these parameters in the cellular medulla. By comparing these limiting cases with experimental observations, we concluded that models in which redistribution of myosin is achieved by decreasing filament stability in the medulla are the most likely candidates.

The gene encoding vitamin K-dependent anticoagulant protein C is expressed in human male reproductive tissues

Protein C is a vitamin K-dependent protein circulating in plasma as a zymogen to an anticoagulant serine protease. After its activation, protein C cleaves and inactivates coagulation factors Va and VIIIa. Human protein C is synthesized in liver and undergoes extensive post-translational modification during its synthesis. Recently, the protein C inhibitor was demonstrated to be synthesized in several organs of the human male reproductive tract. Moreover, vitamin K-dependent protein S, which functions as a co-factor to activated protein C, was found to be synthesized in the Leydig cells of human testis. The aim of this study was to elucidate whether the protein C gene is also expressed in the male reproductive system. Specific immunostaining of protein C was found in Leydig cells of human testis, in the excretory epithelium of epididymis, and in some epithelial glands of the prostate, whereas no immunostaining was detected in seminal vesicles. Northern blotting and non-radioactive in situ hybridization demonstrated protein C mRNA in Leydig cells, in the excretory epithelium of epididymis, and in some of the epithelial glands of the prostate. The mRNA was distributed perinuclearly and the localization was in accordance with the specific immunostaining for protein C. The epithelium of epididymis was also found to contain both protein S mRNA and immunoreactivity. The demonstration of both protein C and protein S immunoreactivities, as well as their mRNAs, in male reproductive tissues suggests as yet unknown local functions for these proteins.

[Liver-protecting and alanine aminotransferase lowering actions of hongning gantai]

Hongning Gantai has a remarkable counteraction on the elevation of ALT activity of mice and rats induced by chemical damages with CCl4 and D-Gal. It can decrease the BSP-retention. The result of pathologic examination indicates that Hongning Gantai can alleviate liver damages of mice and rats and thus has liver-protecting and ALT-lowering actions.

Homozygous APC-resistance combined with inherited type I protein S deficiency in a young boy with severe thrombotic disease

Inherited resistance to activated protein C (APC) is a frequent cause of familial thrombosis. It is associated with a factor V gene point mutation replacing arginine506 in the APC-cleavage site with a glutamine. Thrombotic events are rare during childhood even in patients with homozygous APC-resistance. We now wish to report on a case of severe venous thrombosis, in a 10-year-old boy. He was found to have pronounced APC-resistance due to homozygous factor V gene mutation in combination with inherited type I protein S deficiency. The two traits were independently inherited in the family. The APC-resistance was partially corrected by adding factor V, whereas added protein S was without effect. This is the first reported case of homozygous APC-resistance combined with another inherited prothrombotic disorder. It illustrates how multiple genetic defects may provoke thrombosis at young age and emphasizes the need of complete evaluation of thrombotic patients in order to determine whether multiple risk factors exist.

[Prognosis of filial generation from mothers with systemic lupus erythematosus]

Seventy three pregnancies in 44 women with systemic lupus erythematosus in our hospital from June 1970 to June 1993 were studied. It included 15 spontaneous abortions (20.55%), 8 induced abortions (10.96%), 9 perinatal fetal deaths (12.33%) and 41 live births (56.16%). Therapy with steroids during pregnancy is harmless and effective. It may reduce pregnant loss rate. Of 41 live births, 35 children were followed up (85.36%). Their physical growth, routine blood test and urinalysis were normal. There were no definite evidences of mental developmental abnormality in children. Two girls had been diagnosed of systemic lupus erythematosus at about nine years old. It is possible that systemic lupus erythematosus may be hereditable to female filial generation. So we suggest that the following-up on children born to mothers with systemic lupus erythematosus have to be done till puberty.

Analysis of the role of CD4+ T-cells during murine cytomegalovirus infection in different strains of mice

We examined the role of CD4+ T-cells in peritoneal exudate cells (PECs) during the course of acute murine cytomegalovirus (MCMV) infection in two strains of mice. Cell counts of PECs and cytofluorometric analysis showed that C57BL/6, a resistant strain, had more CD4+ T-cells than BALB/c, a susceptible strain, after intraperitoneal infection of 3 x 10(3) PFU of the Smith strain of MCMV, though both strains had an equivalent number of CD8+ T-cells. CD4+ T-cells of both strains expressed mRNA of IFN-gamma, IL-2, and IL-4 on days 5 and 7 after infection, with much higher expression of these cytokines in C57BL/6 than in BALB/c. At the same time point after infection, macrophages were shown to express mRNA of IL-1 alpha and TNF-alpha with higher expression of IL-1 alpha in C57BL/6 than in BALB/c. Production of nitric oxide, recently shown to be one of the antiviral effector mechanisms of macrophages, by macrophages of both strains was examined showing more production of nitric oxide on day 7 after infection in C57BL/6 than in BALB/c. From these findings, we suggest the possibility that CD4+ T-cells contribute to the protection against MCMV infection via the secretion of cytokines and the resultant activation of macrophages to produce nitric oxide.

Alternative splicing of HLA class I transcripts induced by IFN-gamma and TNF in fibroblasts: release of soluble HLA class I heavy chain and an associate protein

FS-4 fibroblasts were found to produce 37-kDa HLA class I heavy chain in response to IFN-gamma or TNF in a time- and dose-dependent fashion, and a synergism between IFN-gamma and TNF was observed. Immunoprecipitation of IFN-gamma- or TNF-induced FS-4 cell culture supernatants by mAb A1.4 revealed an additional 33-kDa protein in association with the 37-kDa heavy chain. The 33-kDa protein appeared to be expressed in a 38-kDa form on the membrane of FS-4 cells induced by IFN-gamma or TNF, as A1.4 immunoprecipitated the 38-kDa band in association with the 44-kDa transmembrane HLA class I heavy chain. Release of the 37-kDa heavy chain could well be due to an alternative RNA splicing with the deletion of exon 5 encoding the hydrophobic transmembrane region of membrane-anchored HLA class I heavy chain. Northern blot analysis and S1 nuclease protection assay suggested the existence of HLA class I heavy chain mRNA lacking exon 5 in IFN-gamma- or TNF-induced FS-4 cells. Southern blot analysis on the products of reverse transcription-polymerase chain reaction amplification from cytoplasmic RNA confirmed induction of alternative splicing by these cytokines. Our results suggest that cytokine-induced production of soluble HLA class I molecules may play important roles in the regulation of T cell interaction with antigen-presenting cells.

Glycogen synthase kinase-3 and dorsoventral patterning in Xenopus embryos

Glycogen synthase kinase 3 (GSK-3) is homologous to the product of the Drosophila gene shaggy (zeste-white 3), which is required for signalling by wingless during Drosophila development. To test whether GSK-3 is also involved in vertebrate pattern formation, its role was investigated during early Xenopus development. It was found that dominant-negative GSK-3 mutants induced dorsal differentiation, whereas wild-type GSK-3 induced ventralization. These results indicate that GSK-3 is required for ventral differentiation, and suggest that dorsal differentiation may involve the suppression of GSK-3 activity by a wingless/wnt-related signal.

Use of a colorimetric system for yeast susceptibility testing

We examined the reliability and accuracy of a colorimetric assay using Alamar Blue reagent in the performance of susceptibility tests for Candida albicans. We compared the broth macrodilution method recommended by the National Committee for Clinical Laboratory Standards (NCCLS) with a macrodilution method modified with the Alamar reagent and a microdilution method modified with the Alamar reagent. The MICs of fluconazole and itraconazole for 97 isolates of C. albicans and 3 control isolates were tested. For fluconazole, the Alamar-modified broth macrodilution method yielded 94% (91 of 97) concordance within 2 dilutions compared with the NCCLS method, while the microdilution method yielded 95% (92 of 97) concordance. With Alamar-modified methods for itraconazole, broth macrodilution yielded 97% (94 of 97) concordance within 2 dilutions. MICs obtained by the microdilution method, although tightly nested, were shifted to a higher value when compared with those obtained by the NCCLS method; there was only 77% (75 of 97) concordance within 2 dilutions but 97% concordance (94 of 97) within 3 dilutions. Tests by all methods with quality control strains showed excellent reproducibilities. For fluconazole, the methods modified with the Alamar reagent yielded clear endpoints and excellent correlation for the broth macrodilution and microdilution methods. For itraconazole, the methods modified with the Alamar reagent yielded clear endpoints and were reproducible, but higher MICs were obtained by the microdilution methods compared with those obtained by the NCCLS methods.

[An experimental study on the integrated effects of heat-cleaning and detoxifying drugs and fire-purging drugs used in combination]

Heat-cleaning and detoxifying drugs and fire-purging drugs used in combination have been proved able to restore the endotoxin-induced deviant of HCT, blood viscositites, PTT and fibrinolytic activity, and reduce the blood content of both endotoxin and PGE2 in rabbits. In addition, the combination can also decrease the pes swelling percentage in rats as well as evans blue extravasation volume in mice. In practice, however, it should be noted that the bitter and cold qualities of these two kinds of drugs may be harmful to health.

Neurohypophysial AVP concentration in stroke patients

Neurohypophysial arginine vasopressin (AVP) concentrations were determined by RIA in 9 patients with cerebral infarction, 11 patients with intracerebral hemorrhage, 5 patients with subarachnoid hemorrhage and 5 control subjects. The results showed that neurohypophysial AVP concentration in patients with cerebral infarction increased by 225.8% as compared with the control subjects (P < 0.05), and the AVP concentrations in patients with intracerebral and subarachnoid hemorrhage did not change significantly. Brain herniation as a result of intracranial hypertension, gastrointestinal bleeding and hyperglycemia (two clinical manifestations of stress) was seen more frequently in hemorrhagic stroke patients than in ischemic stroke patients. These findings suggest that the ischemic brain damage may contribute to the elevation of neurohypophysial AVP concentration in patients with cerebral infarction.

[Isolation and identification of a pathogen of grasshoppers]

A pathogen was isolated from natural dead pests of Ceracris kiangsu in Geleshan farm of Chongqin. Its pathogenecity was confirmed by the law of KOCK. It was identified as Pseudomonas pseudoalcaligenes according to its physiological and biochemical properties as well as the G + C content of DNA (63.73mol%). The results of preliminary bioassay show that the pathogen can infect the grasshoppers and Ceracris kiangsu, and also can infect other pests of grassland in a certain extent.

Selective activation of VH3A10+ rheumatoid factor producing B cells by staphylococcal enterotoxin D

Staphylococcal enterotoxin D (SED) is a T cell superantigen which selectively targets alpha beta TCRs bearing particular V beta elements. A second function of SED relates to the preferential activation of a B cell subset characterized by a high frequency of rheumatoid factor (RF) producing B cells. To define the molecular basis of the SED-induced B cell repertoire shift, we have analyzed Ig heavy chain genes in B cell clones expanded after SED stimulation and compared them with B cell clones established in the presence of anti-CD3 stimulated helper cells. Gene segments of the VH3 family were most frequently utilized under both stimulation conditions (42% anti-CD3; 47% SED). Sequence analysis of VH3 gene segments demonstrated that the repertoire of VH3 elements in B cell clones from SED driven and anti-CD3 driven cultures were distinct (P = 0.01). RF activity was closely associated with the expression of selected VH3 elements. B cell clones stimulated with SED preferentially expressed VH3A10, whereas VH26 was the gene segment dominantly used in B cell clones expanded with anti-CD3 stimulated helper cells. The usage of JH and DH elements was indistinguishable in SED and anti-CD3 driven B cell clones, suggesting that SED targets VH3+ B cells through a VH-specific mechanism. Comparison of the closely related sequences of the SED responsive VH3A10 and the SED non-responsive VH26 element suggested a role of a sequence polymorphism in the CDR2 reminiscent of B cell reactivity to conventional antigens. In contrast to conventional antigens, SED can induce differentiation of a high frequency of naive B cells. Thus, this staphylococcal enterotoxin combines selective activation of T cells with selective activation of B cells and might be able to direct T cell help to RF producing B cells.

Induction of B cell apoptosis by TH0, but not TH2, CD4+ T cells

Engagement of the T cell receptor molecules with MHC-antigen complexes presented by B cells ascertains antigen specificity in T cell-dependent help. Ligation of MHC molecules on the surface of B cells, however, has not only been implicated in antigen-specific T-B cell interaction, but has also been linked to the induction of B cell apoptosis. To examine the role of T helper cells in either induction of immunoglobulin synthesis or B cell apoptotic death, we have facilitated T cell receptor-MHC interaction through a bacterial superantigen. CD4+ T cell clones could be categorized into two clearly distinct subsets based upon their ability to promote B cell help in the presence of superantigen. One subset of T cell clones supported immunoglobulin synthesis, and thus functioned as effective helper cells. B cells interacting with the second subset of T cells did not differentiate into antibody-secreting cells, but underwent apoptosis. Both types of helper cells were able to provide contact help after anti-CD3 stimulation. Induction of apoptosis was a dominant phenomenon; the addition of the superantigen suppressed immunoglobulin production in B cells activated by anti-CD3-stimulated helper T cells, indicating that the T cells delivered an apoptotic signal to the B cell. T cell clones providing effective MHC restrictive B cell help could be distinguished from T cells facilitating B cell apoptosis based on their lymphokine secretion profile. Induction of B cell apoptosis was a feature of T cells with a TH0 lymphokine pattern. Promotion of MHC-restricted B cell help was associated with a TH2 lymphokine profile. TH1-derived cytokines alone could not substitute for apoptosis-inducing T cells.

Expression and functional characterization of chimeras between human and bovine vitamin-K-dependent protein-S-defining modules important for the species specificity of the activated protein C cofactor activity

Vitamin-K-dependent protein S is an anticoagulant plasma protein functioning as a cofactor to activated protein C (APC) in the degradation of factors Va and VIIIa. The APC-cofactor function of protein S is species specific, as human protein S potentiates the anticoagulant activity of human but not that of bovine APC, whereas bovine protein S is a cofactor to APC from both species. To elucidate which modules in protein S determine the species specificity, in vitro mutagenesis was used to construct six recombinant chimeric molecules between human and bovine protein S. Wild-type human and bovine protein S and the chimeras were expressed in 293 cells and the recombinant proteins purified by monoclonal antibody affinity chromatography. The recombinant proteins were found to be post-translationally modified, they bound C4b-binding protein and were functionally active as cofactors to APC. Chimeras having both the thrombin-sensitive region (TSR) and the first epidermal-growth-factor-(EGF)-like module of bovine origin expressed APC-cofactor activity similar to that of bovine protein S. Those chimeras, in which TSR or EGF1 derived from different species, manifested APC-cofactor activity similar to that of human protein S, i.e. they did not express cofactor activity to bovine APC. These data indicate that sequence differences in the TSR and EGF1 of human and bovine protein S cause the species specificity of the APC-cofactor activity. The data support the concept that these two modules of protein S interact with APC on the surface of negatively charged phospholipids.

[A study on the relationship between in-door air pollution and chronic obstructive pulmonary disease in Xuanwei County]

A cross-sectional study was conducted to explore the relationship between in-door air pollution caused by different fuels for domestic use and chronic obstructive pulmonary disease (COPD) in local population. A total population of 10892 were sampled and analyzed. Results showed in-door air pollution caused by coal-burning was the major risk factor for COPD in Xuanwei County. The risk of residents using soft coal and anthracite to suffer from COPD was 4.36 and 1.55 times, respectively, higher than in those using fire wood.

C-fos expression in vivo in human lymphocytes in response to stress

1. Blood samples from which lymphocytes were isolated were obtained from patients immediately prior to cardiac catheterization (stress period) and again four to five hours later (post-stress period). Blood was also taken from a normal non-stressed control subject. 2. Lymphocyte c-fos mRNA was reverse transcribed followed by strand synthesis of DNA template and amplification using PCR with sequence-specific primers. 3. C-fos mRNA was detectable in lymphocytes from the normal control subject and in patient samples obtained immediately prior to cardiac catheterization, but was not detectable in patient samples obtained four to five hours later. 4. Possible mechanisms for these findings include a stress-related decrease in lymphocyte proliferation and differentiation or a negative feedback effect of the c-fos protein on transcription of the c-fos gene. 5. These findings suggest that it may be possible to monitor peripheral early gene expression as a marker for a variety of conditions including stress, psychiatric disorders and the response to psychotropic drugs.

The gene encoding vitamin K-dependent anticoagulant protein S is expressed in multiple rabbit organs as demonstrated by northern blotting, in situ hybridization, and immunohistochemistry

Vitamin K-dependent protein S is an anticoagulant plasma protein that functions as a co-factor to activated protein C in the degradation of coagulation factors Va and VIIIa. We investigated the tissue/cellular distribution of protein S synthesis by Northern blotting, in situ hybridization, and immunohistochemistry. Northern blotting together with in situ hybridization, using specific oligodeoxynucleotide probes, demonstrated protein S mRNA in liver, lung, testis, epididymis, ovary, uterus, and brain. In the reproductive system, protein S mRNA was present in the cytoplasm of Leydig cells, interstitial cells of the ovary, epithelial cells of the epididymis, and in the endometrium, including endometrial mucous glandular membrane in the myometrium. Bronchial epithelial cells and alveolar macrophages were positive in the respiratory system. In the central nervous system, pyramidal neurons in the cerebral cortex and in the hippocampal region, and dentate fascia neurons gave strongly positive signals. Immunohistochemistry with monoclonal antibodies yielded a staining pattern that correlated well with results of in situ hybridization. In conclusion, results from Northern blotting, in situ hybridization, and immunohistochemistry suggested that rabbit protein S is expressed in several extrahepatic tissues. The presence of protein S transcripts in these fully differentiated cells suggests a cell type-specific gene expression which may be related to local anticoagulation or to other as yet unknown protein S functions.

Identification of the same factor V gene mutation in 47 out of 50 thrombosis-prone families with inherited resistance to activated protein C

Resistance to activated protein C (APC) is the most prevalent inherited cause of venous thrombosis. The APC resistance phenotype is associated with a single point mutation in the factor V gene, changing Arg506 in the APC cleavage site to a Gln. We have investigated 50 Swedish families with inherited APC resistance for this mutation and found it to be present in 47 of them. Perfect cosegregation between a low APC ratio and the presence of mutation was seen in 40 families. In seven families, the co-segregation was not perfect as 12 out of 57 APC-resistant family members were found to lack the mutation. Moreover, in three families with APC resistance, the factor V gene mutation was not found, suggesting another still unidentified cause of inherited APC resistance. Of 308 investigated families members, 146 were normal, 144 heterozygotes, and 18 homozygotes for the factor V gene mutation and there were significant differences in thrombosis-free survival curves between these groups. By age 33 yr, 8% of normals, 20% of heterozygotes, and 40% of homozygotes had had manifestation of venous thrombosis.

Epidemiology of oral candidiasis in HIV-infected patients: colonization, infection, treatment, and emergence of fluconazole resistance

PURPOSE

To study the epidemiology of oral candidiasis and the effect of treatment of thrush in human immunodeficiency virus (HIV)-infected patients.

PATIENTS AND METHODS

We conducted a prospective observational study of 92 patients over 1 year, including a nonblinded, randomized treatment trial of thrush with clotrimazole troches or oral fluconazole. Oral sites were cultured monthly and when thrush occurred. Candida albicans strains were typed by contour-clamped homogeneous electric field (CHEF) electrophoresis. Changes in strains were evaluated over time and in regard to their associations with particular sites, episodes of thrush, relapse after treatment, and colonization of sexual partners. Susceptibility to fluconazole was tested and CHEF analysis was done on these strains to determine the epidemiology of fluconazole resistance.

RESULTS

Yeasts colonized 84% of patients. C albicans accounted for 81% of all isolates and was separated into 34 distinct strains. Most patients had persistent carriage of 1 or 2 dominant strains of C albicans. Three couples shared strains. Nineteen different C albicans strains caused 82 episodes of thrush in 45 patients. CD4 < 200/microL was associated with development of thrush. Clinical cure rates were similar with fluconazole (96%) and clotrimazole (91%), but mycologic cure was better with fluconazole (49%) than clotrimazole (27%). Following mycologic cure, colonization recurred with the same strain 74% of the time. Colonization with Torulopsis glabrata and Saccharomyces cerevisiae increased after treatment with either drug, but these organisms were never a sole cause of thrush. In a subset of 35 patients followed for over 3 months in whom fluconazole susceptibilities were performed, minimum inhibitory concentrations (MICs) to fluconazole increased only in those on fluconazole prophylaxis. Clinical failure of fluconazole was associated with an MIC > or = 64 micrograms/mL in 3 patients, and with an MIC of 8 micrograms/mL in 1 patient. In 2 of these 4 patients, the prior colonizing strain developed fluconazole resistance. In the other 2, new resistant strains were acquired.

CONCLUSIONS

Many different strains of C albicans colonize and cause thrush in patients infected with HIV. Patients are usually persistently colonized with a single strain, and recurrences following treatment are usually due to the same strain. Transmission of strains may occur between couples. Fluconazole and clotrimazole are equally effective in treating thrush, but mycologic cure occurs more often with fluconazole. Fluconazole resistance in C albicans occurs most often in patients who have low CD4 counts and are taking fluconazole prophylactically for recurrent thrush. Fluconazole resistance may occur through acquisition of a new resistant strain or by development of resistance in a previously susceptible strain.

Azole resistance in oropharyngeal Candida albicans strains isolated from patients infected with human immunodeficiency virus

For 212 oropharyngeal isolates of Candida albicans, the fluconazole MICs for 50 and 90% of strains tested were 0.5 and 16 micrograms/ml, respectively, and those of itraconazole were 0.05 and 0.2 micrograms/ml, respectively. Of 16 isolates for which fluconazole MICs were > 64 micrograms/ml, itraconazole MICs for 14 were < or = 0.8 micrograms/ml and for 2 were > 6.4 micrograms/ml. Most fluconazole-resistant strains remained susceptible to itraconazole; whether itraconazole will prove effective for refractory thrush remains to be shown.

Studies of the biosynthesis of 3,6-dideoxyhexoses: molecular cloning and characterization of the asc (ascarylose) region from Yersinia pseudotuberculosis serogroup VA

The 3,6-dideoxyhexoses are found in the lipopolysaccharides of gram-negative bacteria, where they have been shown to be the dominant antigenic determinants. Of the five 3,6-dideoxyhexoses known to occur naturally, four have been found in various strains of Salmonella enterica (abequose, tyvelose, paratose, and colitose) and all five, including ascarylose, are present among the serotypes of Yersinia pseudotuberculosis. Although there exists one report of the cloning of the rfb region harboring the abequose biosynthetic genes from Y. pseudotuberculosis serogroup HA, the detailed genetic principles underlying a 3,6-dideoxyhexose polymorphism in Y. pseudotuberculosis have not been addressed. To extend the available information on the genes responsible for 3,6-dideoxyhexose formation in Yersinia spp. and facilitate a comparison with the established rfb (O antigen) cluster of Salmonella spp., we report the production of three overlapping clones containing the entire gene cluster required for CDP-ascarylose biosynthesis. On the basis of a detailed sequence analysis, the implications regarding 3,6-dideoxyhexose polymorphism among Salmonella and Yersinia spp. are discussed. In addition, the functional cloning of this region has allowed the expression of Ep (alpha-D-glucose cytidylyltransferase), Eod (CDP-D-glucose 4,6-dehydratase), E1 (CDP-6-deoxy-L-threo-D-glycero-4- hexulose-3-dehydrase), E3 (CDP-6-deoxy-delta 3,4-glucoseen reductase), Eep (CDP-3,6-dideoxy-D-glycero-D- glycero-4-hexulose-5-epimerase), and Ered (CDP-3,6-dideoxy-L-glycero-D-glycero-4-hexulose-4-reductase), facilitating future mechanistic studies of this intriguing biosynthetic pathway.

[Effect of nifedipine on T wave in ischemic myocardium]

Calcium antagonists are generally considered to have no substantial effect on repolarization of the myocardium, so they have no direct effect on T wave, either. But in a pig model of myocardial ischemia, intracoronary nifedipine was found to reverse the inverted T wave induced by ischemia to upright promptly. Ten pigs were anesthetized with the chest opened, anterior interrentricular branch of left coronary artery (LAD) was narrowed to 4.67 kPa of LAD pressure, and then adenosine or nifedipine was infused into the coronary respectively. During the 9-minute ischemia, intracoronary adenosine or intracoronary nifedipine got the similar HR, LVEDP, LVDP, CAP, CAQ, and the intracoronary adenosine even got higher CAQ than the intracoronary nifedipine did. However, the T wave was retained inverted during the adenosine infused, but during the intracoronary nifedipine, the inverted T wave was promptly turned upright. The relevant factors and mechanisms are discussed.

[Effects of endotoxin on coronary circulation]

To investigate the effects of endotoxin (ETX) on coronary circulation, we infused endotoxin (4ng/ml) intravenously in a small dose (0.3ng/kg.min-1) which did not reduce the blood pressure, nor did it disturb the coronary autoregulation, and the flow kept constant during the ETX infusion. But when the left coronary artery descending branch (LAD) was narrowed and the LAD pressure was reduced to 4.67kPa, the ETX showed a vasodilator effect on the LAD (pre-ETX 65.2 +/- 29.2 ml/min, post-ETX 89.5 +/- 32.7 ml/min, P < 0.05). This effect suggested that the ETX in a small dose had a vasodilator effect on a narrowed coronary artery, even when it did not disturb the hemodynamics. The possible mechanisms were surveyed preliminarily.

[Comparative study of ischemia-induced and reperfusion-induced ventricular fibrillation in pigs]

To have a better understanding of reperfusion-induced ventricular fibrillation (VF), we studied the relevant morbidity in pigs and compared it with that of the ischemia-induced VF. In 10 hearts of anesthetized chest-open pigs, a total of 127 cycles of various degrees and varied duration of ischemia and reperfusion were completed. VF occurred 13 times (10.2%). Of these, 11 were ischemia-induced VF, while only 2 were reperfusion-induced VF. In two cases of ischemia-induced VF, electric defibrillation failed before the reestablishment of left anterior interventricular branch of coronary artery flow, but after adequate reflowing, all VF turned out to be sinus-rhythm by electric defibrillation. The results suggest that ventricular fibrillation be mainly induced by ischemia but less induced by reperfusion.

[The effects of extracellular matrix on Sertoli cells of rats in vitro]

This study was performed to observe the effects of extracellular matrix (ECM) on Sertoli cells attachment, spreading and morphology in vitro. The ECM used were FN and LN and biomatrix isolated from the liver and lung. The results showed that FN and LN promoted Sertoli cell attachment and spreading. The Sertoli cells grown on the biomatrix isolated from the lung assumed a columnar shape like that seen in vivo. The cells grown on biomatrix from the liver did not.