Mass Measurement of Upper fp-Shell N=Z-2 and N=Z-1 Nuclei and the Importance of Three-Nucleon Force along the N=Z Line

Using a novel method of isochronous mass spectrometry, the masses of ^{62}Ge, ^{64}As, ^{66}Se, and ^{70}Kr are measured for the first time, and the masses of ^{58}Zn, ^{61}Ga, ^{63}Ge, ^{65}As, ^{67}Se, ^{71}Kr, and ^{75}Sr are redetermined with improved accuracy. The new masses allow us to derive residual proton-neutron interactions (δV_{pn}) in the N=Z nuclei, which are found to decrease (increase) with increasing mass A for even-even (odd-odd) nuclei beyond Z=28. This bifurcation of δV_{pn} cannot be reproduced by the available mass models, nor is it consistent with expectations of a pseudo-SU(4) symmetry restoration in the fp shell. We performed ab initio calculations with a chiral three-nucleon force (3NF) included, which indicate the enhancement of the T=1 pn pairing over the T=0 pn pairing in this mass region, leading to the opposite evolving trends of δV_{pn} in even-even and odd-odd nuclei.

[A comparative study of artificial intelligence nasal polyp classification based on whole-slide imaging and JESREC diagnostic criteria]

Objective: To explore the types and clinical characteristics of chronic rhinosinusitis with nasal polyps (CRSwNP) based on artificial intelligence and whole-slide imaging (WSI), and to explore the consistency of the diagnostic criteria of the Japanese epidemiological survey of refractory eosinophilic chronic rhinosinusitis (JESREC) in Chinese CRSwNP patients. Methods: The data of 136 patients with CRSwNP (101 males and 35 females, aging 14 to 70 years) who underwent endoscopic sinus surgery from 2018 to 2019 in the Department of Otorhinolaryngology Head and Neck Surgery, the Third Affiliated Hospital of Sun Yat-sen University were analysed retrospectively. The preoperative clinical characteristics of patients were collected, such as visual analogue scale (VAS) of nasal symptoms, peripheral blood inflammatory cell count, total immunoglobulin E (IgE), Lund-Kennedy score and Lund-Mackay score. The proportion of inflammatory cells such as eosinophils, lymphocytes, plasma cells and neutrophils were calculated on the WSI of each patient through artificial intelligence chronic rhinosinusitis evaluation platform 2.0 (AICEP 2.0), and the specific type of nasal polyps was then obtained as eosinophilic CRSwNP (eCRSwNP) or non-eosinophilic CRSwNP (non-eCRSwNP). In addition, the JESREC diagnostic criteria was used to classify the nasal polyps, and the classification results were compared with the current gold standard for nasal polyps diagnosis (pathological diagnosis based on WSI). The accuracy, sensitivity and specificity of the diagnostic criteria of JESREC were evaluated. The data were expressed in M (Q₁, Q₃) and statistically analyzed by SPSS 17.0. Results: There was no significant difference between eCRSwNP and non-eCRSwNP in age distribution, gender, time of onset, total VAS score, Lund-Kennedy score or Lund-Mackay score. However, there was a significant difference in the ratio of nasal polyp inflammatory cells (eosinophils 40.5% (22.8%, 54.7%) vs 2.5% (1.0%, 5.3%), neutrophils 0.3% (0.1%, 0.7%) vs 1.3% (0.5%, 3.6%), lymphocytes 49.9% (39.3%, 65.9%) vs 82.0% (72.8%, 87.5%), plasma cells 5.1% (3.6%, 10.5%) vs 13.0% (7.4%, 16.3%), χ² value was 9.91, 4.66, 8.28, 5.06, respectively, all P<0.05). In addition, eCRSwNP had a significantly higher level of proportion of allergic symptoms (nasal itching and sneezing), asthma, peripheral blood eosinophil and total IgE (all P<0.05). The overall accuracy, sensitivity and specificity of the JESREC diagnostic criteria was 74.3%, 81.3% and 64.3%, respectively. Conclusions: The eCRSwNP based on artificial intelligence and WSI has significant high level of allergic symptoms, asthma, peripheral blood eosinophils and total IgE, and the percentages of inflammatory cells in nasal polyps are different from that of non-eCRSwNP. The JESREC diagnostic criteria has good consistency in our research.

[Clinical phenotype of Alport syndrome in monozygotic twins]

Objective: To analyze the consistency of the clinical phenotype of Alport syndrome between monozygotic twins. Methods: This retrospective study included identical twins with Alport syndrome who met the inclusion and exclusion criteria and were admitted to Peking University First Hospital from January 2000 to March 2019. Their clinical data and urinary epidermal growth factor (uEGF) level were extracted from the on-line registry system of hereditary kidney diseases, and analyzed retrospectively. Results: Three pairs of monozygotic twins with X-linked Alport syndrome from three non-consanguineous families were included. The consistency of the genotype status between the twins tended to confirm their monozygotic relationship. The first twins were term infants, and the twin 1A had a normal birth weight (2 500 g) while twin 1B was small for gestational age (2 450 g) . The other two pairs of twins were preterm, with different birth weights between twins 2 (2A is 2 450 g, 2B is 1 900 g) , but similar birth weights between twins 3. Although raised in the same environment, compared with twin 1A, 1B had obvious growth retardation. However, growth rate in the remaining twins were consistent. The renal abnormalities were not exactly the same between both twins 1 and twins 2, but was almost the same in twins 3. Both 1A and 1B were characterized by massive proteinuria and renal dysfunction, whereas 1B had worse renal function. At the last follow-up, 1A was diagnosed with stage 3 of chronic kidney disease (CKD) whereas 1B was CKD stage 4. Although renal function in twins 2 were normal, 2A had prominent proteinuria(24 h urinary total protein: 0.22 g) while 2B only had microalbuminuria(urinary albumin-to-creatinine ratio: 65 mg/g). Compared with the age-matched healthy controls, the concentration of uEGF normalized by urine creatinine (uEGF/Cr) were significantly lower in these twins. Besides, the twin-boy who had lower estimated glomerular filtration rates had lower uEGF/Cr. However, the extrarenal manifestations such as ocular and acoustic abnormalities were similar between the twins. Twins 2 and 3 showed bilateral temporal retinal thinning, and twins 1 both had binaural mild mid-low frequency sensorineural deafness. Conclusions: Renal manifestations of X-linked Alport syndrome in monozygotic twins may differ from each other, whereas the extrarenal manifestations including ocular and acoustic abnormalities may be consistent. Low birth weight and growth retardation may be associated with the progression of renal dysfunction.

Decreased expression of MS4A12 inhibits differentiation and predicts early stage survival in colon cancer

Lack of normal differentiation was considered as a common defect in cancer cells. MS4A12, a colon-specific gene, belongs to MS4A family that plays an important role in differentiation, proliferation and cell cycle regulation. The aim of the study was to investigate MS4A12 role in colon cancer cell differentiation and its prognostic value in colon cancer. We used sodium butyrate (BS) to set up differentiated model of colon cancer cell line LoVo. Cell differentiation was evaluated with ALP activity and E-cadherin. We used BS (4 mmol/L) inducing differentiation of LoVo cell and found after BS treated over 48h MS4A12 variant-1 (one of MS4A12 gene transcripts) as well as ALP and E-cadherin of LoVo cells were all increased significantly. When silence MS4A12 variant-1, the elevation of ALP and E-cadherin in BS-treated cells were all inhibited. Besides, after silence MS4A12 variant-1, the cells showed significant resistances to BS function of induction cell cycle arrest and apoptosis. Survival analysis used GEO datasets GSE39582 and GSE38832 that include 681 distinct colon cancer samples. Log-rank test and Cox's proportional hazards regression were applied to analyzing single and multiple prognostic variables, respectively. In early stage colon cancer, the patients with low MS4A12 expression had a poor survival (HR=1.72; p=0.036), while in advanced stage colon cancer MS412 had little prognostic value (HR=0.89; p=0.601). These results indicated MS4A12 might relate to colon cancer cell differentiation and supposed to be a risk classification marker for early stage colon cancer.

[Operative technique and follow-up effect of endoscopic congenital choanal atresia and dilatation]

Objective:To discuss the operative technique and follow-up effect of endoscopic dilatation and plasty for congenital choanal atresia in infants. Method:Clinical data of 7 children with congenital choanal atresia operative treatmented during September 2016 to January 2018 were analyzed retrospectively. the follow-up were followed closely and analyz the operative effect. Result: Seven cases were diagnosed by electronic nasopharyngoscope, nasal CT confirm the nature of atresia plate, and all 7 case successfully complete the operation. Follow-up survey ranged from 8 months to 23 months, postoperative nasal ventilation is good. The first case of bilateral choanal atresia was removed the nasal stenting after operative 3 months, and founded stenosis 1 month later. Reoperation to enlarge the choanal and retained the nasal stenting for 6 months, no restenosis or atresia after 15 months of follow-up. One patient gave up further treatment because of his own reasons and was lost to follow-up. The other 5 cases had no obvious constriction, good ventilation and no operative complications.Conclusion:Electronic nasopharyngoscope is noninvasive, convenient and accurate in the diagnosis of choanal atresia. Nasal CT confirm the nature of the atresia plate. Endoscopic dilatation and plasty of choanal atresia should be retained the nasal stenting for more than 6 months, avoid re-constriction. .

[Relationships between serum cystatin C, chemerin levels and subclinical atherosclerosis in type 2 diabetes mellitus patients]

Objective: To investigate the relationships between serum cystatin C (Cys C), chemerin levels and subclinical atherosclerosis in type 2 diabetes mellitus (T2DM) patients. Methods: A cross-sectional study was carried out between January 2016 and January 2018, and T2DM patients with carotid intima-media thickness (IMT) less than 1.1 mm were selected as subjects (100 males and 80 females, aged 40-60 years). The brachial-ankle pulse wave velocity (baPWV) ≥ 1 700 cm/s was set as the observation group (subclinical atherosclerosis) and baPWV<1 700 cm/s as the control group (non-subclinical atherosclerosis). Physical and blood examination were performed in both groups. Serum Cys C and chemerin levels were measured and their relationship with subclinical atherosclerosis was analyzed. Results: There was a statistically significant correlation between serum creatinine (r=0.167, P=0.011) and baPWV in the observation group, but not in the control group (r=0.105, P=0.070). Multiple linear regression analysis showed that age, duration of diabetes, serum creatinine, estimated glomerular filtration rate (eGFR), Cys C and chemerin were independently associated with baPWV, while high sensitive C reactive protein (hsCRP) and glycosylated hemoglobin (HbA1c) were not associated with baPWV. The elevation of serum Cys C (β'=0.393, P=0.003) and chemokine (β'=0.340, P=0.007) were correlative factors for atherosclerosis. Conclusion: The level of serum Cys C and chemerin is possibly related to the occurrence and development of subclinical atherosclerosis in T2DM patients.

[Association of α-actinin-3 gene polymorphism and muscle strength of postmenopausal women]

Objective: To explore the association between α-actinin-3 (ACTN3) polymorphism and muscle strength in postmenopausal women. Methods: Five hundred and ninety-eight postmenopausal women with an average of (62.9±7.0) years old in Dongcheng District of Beijing were included. The ACTN3 polymorphism including rs540874, rs618838 and rs2229456 were genotyped by Sequenom Mass Array to explore their associations with muscle strength. One hundred and sixty-three of them were trained with regular Tai chi movement while 271 were administered with elemental calcium 600 mg/d combined with Vitamin D 800 U/d or calcitriol 0.25 μg/d for 2 years. Association between changes of muscle strength and ACTN3 polymorphism were analyzed. Results: The rs540874 genotypes were found to be significantly associated with chair stand test[GG (9.02±3.85) s vs GA (9.27±4.14) s vs AA (9.68±5.00) s, P=0.015]. Right grip strength in women with G allele were likely to be higher compared with A allele, but it was not statistically significant (P=0.056). Multiple linear regression showed that the chair stand test of AA genotype was statistically longer than that of GG and GA genotype (β=2.639, 95% CI: 1.632-4.646, P=0.010). The associations between rs618838, rs2229456 genotypes and muscle strength of both lower and upper limbs were not significant (all P>0.05). In addition, muscle strength of lower limbs of patients with rs540874 genotyped with G allele, rs618838 genotyped with C allele and rs2229456 genotyped with A allele increased significantly after enhanced exercise and vitamin D supplementation (all P<0.05). Conclusions: The rs540874 polymorphism of ACTN3 gene was associated with the muscle function of lower limb in postmenopausal women. The improvement of muscle strength after intervention were possibly correlated with rs540874, rs618838 and rs2229456 polymorphisms.

[Prognostic values of grading system for lymph vessel tumor emboli in patients with invasive breast carcinomas of no special type]

Objective: To investigate the grading system for lymph vessel tumor emboli and its prognostic value in patients with invasive carcinomas of no special type (ICNST) of the breast. Methods: Clinical data of 466patients with ICNST were collected from January 2006 to December 2008 in the Fourth Hospital of Hebei Medical University. The expression levels of D2-40, estrogen receptor(ER), progesterone receptor(PR) and human epidermal growth factor receptor 2 (HER-2) were analyzed using immunohistochemical staining. Grades for lymph vessel tumoremboli were classified based on the number of mitotic and apoptotic figures in tumor cells under a high-power field. Correlation analysis was performed using Spearman rank correlation test. Kaplan-meier curves and Log-rank tests were used to analyze the survival rate. Multivariate Cox proportional hazard model was used to analyze the prognostic factors. Results: Among the 466 patients, grades for lymph vessel tumor emboli were categorized as follows: 280 cases were grade 0 (60.1%); 112 cases were grade 1 (24.0%); 58 cases were grade 2 (12.5%); 16 cases were grade 3 (3.4%). Correlation analyses showed that lymph vessel tumor emboli grading system was positively correlated with lymph node metastasis (r=0.365, P<0.001). Kaplan-Meier univariant analysis showed that histological grading, lymph vessel tumor emboli grading system, lymph node metastasis, the expression levels of ER, PR and HER-2 and molecular typing were associated with prognosis of patients (P<0.05 for all). Multivariate analysis of Cox proportional hazard model showed that lymph vessel tumor emboli grading system and lymph node metastasis were independent prognostic factors in patients with ICNST(P<0.05 for all). Conclusion: Grading system for lymph vessel tumor emboli canpredict the clinical outcome of patients with ICNST.

[Thoracoscopy in diagnosis and treatment of pleural diseases in children]

Objective: To investigate the value of thoracoscopy in diagnosis and treatment of pleural diseases in children. Method: Clinical manifestations and treatment outcomes of 19 patients who had refractory pleural diseases treated with thoracosocy during May 2011 to August 2016 in Hunan Provincial People's Hospital were retrospectively analyzed. In 19 cases, 15 were male and 4 were female, with an average age of (4.8±2.0) years. Thirteen patients had left pleural lesion, while 5 patients had right lesion, and 1 had bilateral lesions. Result: All cases were successfully treated with thoracoscopy without emergent thoracotomy. Pre- and post operative diagnosis was compatible in 10 cases, including 8 cases of empyema (Streptococcus pneumoniae infection in 6 cases, and Staphylococcus Aureus infection in 2 cases), and 2 cases of tuberculous pleuritis. Nine patients who had not been clearly diagnosed before surgery were diagnosed to be empyema (4 case), tuberculous pleuritic (3 cases), mycoplasma infection (1 case), and foreign body with infection (1 case) by thoracoscopy. The average duration of post-op closed thoracic drainage was (4.7±2.3) days. The average time to get normal temperature was (2.4±2.6) days. And the average length of hospital stay was (6.7±1.8) days. No hemothorax, chylothorax, or need for analgesic occurred. Conclusion: Thoracoscopy can be recommended for diagnosis and treatment of refractory pleural lesions diseases in children, with minimal trauma and complications.

Secondhand smoke exposure of children at home and prevalence of parental smoking following implementation of the new tobacco control law in Macao

OBJECTIVE

To investigate secondhand smoke exposure (SHS) of children at home and the prevalence of parental smoking after implementation of the new tobacco control law in Macao. This study explored whether the smoking ban in public places in Macao has decreased the prevalence of smoking or led to increased SHS exposure of children at home. As smokers cannot smoke in public places any more, they may smoke at home more frequently; a displacement effect of smoke-free legislation.

STUDY DESIGN

Cross-sectional survey.

METHODS

This study surveyed 337 fathers and 538 mothers. Questions from a subset of key questions from the Global Adult Tobacco Survey (2nd edition) were applied to assess the SHS exposure of children and the prevalence of parental smoking since the smoking ban. A classification tree analysis was used to analyse the factors increasing SHS exposure of children.

RESULTS

The prevalence of SHS exposure in children at home was 41.3%. The prevalence rates of paternal and maternal smoking were 43.7% and 3.8%, respectively. Compared with data reported by the Health Bureau of Macao SAR in 2011, the prevalence of parental smoking and the prevalence of SHS exposure of children at home have not decreased since the smoking ban. Analysis of the factors increasing the prevalence of SHS exposure of children indicated that fathers with an education level below high school were more likely to contribute to this increase, compared with fathers with a high school education or more (48.2% vs 32.4%, respectively). In addition, fathers represented the majority of smokers at home, accounting for 92.0% of 415 smoking parents. The prevalence of paternal smoking (82.0%) in the group of children with SHS exposure was much higher than that in the unexposed group (16.7%, Chi-squared test = 367.199, P = 0.000). The SHS exposure of children increased consistently with the decrease in paternal education level. This was consistent with the increasing prevalence of paternal smoking as paternal education level decreased. SHS exposure was most common among children whose fathers had an education level below high school and whose mothers were aged ≤29 years (75.0%).

CONCLUSIONS

This study did not find any decline in the prevalence of parental smoking after the smoking ban. These parents were more likely to smoke at home after the ban, leading to more frequent SHS exposure for their children.

[Certain experiences in sequential treatment of occlusal reconstruction]

Occlusal reconstruction is a complex sequential treatment. The treatment may involve changes in occlusal vertical dimension and the full dental arch occlusal surface reconstruction. In this paper, we discussed the most concerned aspects of prosthodontists during the occlusal reconstruction sequential treatment, how to determine the suitable occlusal vertical dimension, rebuilding of occlusal plane, and consideratiom of temporomandibular joint disorders during reconstruction treatment. The prosthodontists should adopt the multidisciplinary collaboration mode of thinking in analysis, design, treatment, and restoration processes, regarding patients' individual characteristic through the occlusal reconstruction sequential treatment, and to reach healthy, functional, aesthetic outcome eventually.

Autophagy: A double-edged sword in intervertebral disk degeneration

Autophagy is a homeostatic mechanism through which intracellular damaged organelles and proteins are degraded and recycled in response to increased metabolic demands or stresses. Although primarily cytoprotective, dysfunction of autophagy is often associated with many degenerative diseases, including intervertebral disc (IVD) degeneration (IDD). As a main contributing factor to low back pain, IDD is the pathological basis for various debilitating spinal diseases. Either higher or lower levels of autophagy are observed in degenerative IVD cells. Despite the precise role of autophagy in disc degeneration that is still controversial, with difference from protection to aggravation, targeting autophagy has shown promise for mitigating disc degeneration. In the current review, we summarize the changes of autophagy in degenerative IVD cells and mainly discuss the relationship between autophagy and IDD. With continued efforts, modulation of the autophagic process could be a potential and attractive therapeutic strategy for degenerative disc disease.

Miniature in-line photonic crystal fiber etalon fabricated by 157 nm laser micromachining

A miniature in-line fiber-optic Fabry-Perot etalon is fabricated on a photonic crystal fiber (PCF) by using 157 nm laser micromachining for the first time to our knowledge. Experimental results show that such a PCF-based etalon has an excellent fringe visibility of up to approximately 26 dB due to the mirror-finish quality of the two cavity surfaces inside the PCF. This etalon can be used as an ideal sensor for precise strain measurement under high temperature of up to 800 degrees C. It can also offer some other outstanding advantages, such as fast and easy fabrication, high reproducibility, capacity of mass production, low cost, low temperature-strain cross-sensitivity, and high signal-to-noise ratio.

Mild hypothermia reduces ICAM-1 expression, neutrophil infiltration and microglia/monocyte accumulation following experimental stroke

Mild hypothermia is an established neuroprotectant against cerebral ischemic injury. Studies have shown that inflammation potentiates cerebral ischemic injury, particularly in the setting of reperfusion. To further elucidate the mechanism by which mild hypothermia attenuates the inflammatory response, we assessed endothelial intercellular adhesion molecule-1 (ICAM-1) expression, neutrophil and monocyte infiltration, and microglial activation following 2 h of transient focal cerebral ischemia under normothermic and mildly hypothermic conditions. Ischemia was induced using the intraluminal suture method in Sprague-Dawley rats. Immunohistochemistry was used to detect endothelial ICAM-1, infiltrating neutrophils and monocytes, and microglia at 1, 3, and 7 days post-ischemia. Immunopositive cell and vessel densities were measured in the peri-infarct region. Mild hypothermia was associated with decreased neutrophils at 1 and 3 days post-ischemia, decreased ICAM-1-positive vessels at 1, 3, and 7 days, and decreased monocytes/activated microglia at 3 and 7 days, but not at 1 day. These data demonstrate that mild hypothermia significantly reduces endothelial adhesion molecule expression, acute (neutrophil) and subacute (monocyte) leukocyte infiltration, and microglial activation up to 7 days following insult in a rodent model of transient focal cerebral ischemia.

[Relationship between the axially lymph nodes metastases and the bone metastases in patients with the breast cancer]

OBJECTIVE

To investigate the relationship between the axially lymph nodes metastases and the bone metastases in patients with the breast cancer.

METHODS

Lymphadenotomy of the axially lymph nodes had been performed on patients with the breast cancer, and the excised axially lymph nodes were observed by pathological examination. All patients underwent postoperatively total bone scan with single photon emission computer tomography (SPECT) periodically.

RESULTS

Among 292 patients with the breast cancer, the bone metastatic rates of low and high differentiating tumor were 27.3% (6/22) and 45.2% (122/272) respectively, the bone metastatic rates in both tumors had no difference (P > 0.1). The bone metastatic rate was 54.3% (100/184) in patients suffered from the axially lymph nodes metastases, and 25.9% (28/108) in non-metastases patients respectively, the difference of their bone metastatic rates was significant (P < 0.001). The bone metastatic rate was 48.4% (62/128) in patients suffered from the metastases of axially lymph nodes after operation less 2 years, and 67.8% (38/56) after operation more than 2 years respectively, the difference of their bone metastatic rates was not significant (P < 0.5).

CONCLUSIONS

There is no relationship between the bone matastatic rates and the pathological type of tumor. The bone metastatic rates of patients with the axially lymph nodes metastases are higher than those with non-metastases of axially lymph nodes. In addition, the bone metastatic rates of patients with the axially lymph nodes metastases increase with time prolongation.

[99mTc-ECD SPECT CBF-quantification and its clinical significance]

OBJECTIVE

To establish a quantitative method of non-blood withdrawn with 99mTc-ECD SPECT for measuring cerebral blood flow (CBF).

METHOD

Combining three compartment models and technology of the best parameters by computer with 99mTc-ECD SPECT to quantitate CBF and regional cerebral blood flow (rCBF) in control group and patient group.

RESULTS

The CBFs of the control group (8 cases) and the patient group (16 cases) were (57.16 +/- 4.21) ml.min-1/100 g and (38.80 +/- 8.21) ml.min-1/100 g, respectively. The CBF and rCBF were significantly lower in patient group than those in control group (P < 0.05).

CONCLUSION

The method is simple and more convenient for quantification of CBF in patients with brain disorders, and it may increase the diagnostic sensitivity and the accuracy of focus location. It is suggested that the method is accurate and reliable.

Preliminary studies on target antigens for the diagnosis of Trichomonas vaginalis infection

Trichomonas vaginalis, a parasitic protozoa residing in the human urogenital tract, causes one of the most common sexually transmitted diseases, trichomoniasis. Clinical diagnosis of T. vaginalis infection mainly involves a wet-mount microscopic examination, and a culture method, and both of which are either laborious or time-consuming. An immunodiagnostic strategy is under development, which is based on the fact that T. vaginalis releases various protein factors, notably proteinases, into the culture medium, some of which can also be detected in vaginal washes. These factors are closely related to the clinical presentation of trichomonad vaginitis, and thusly may serve as potential earmarks for diagnosis. We have attempted to identify the most appropriate target antigen(s) by screening and analyzing the profile of T. vaginalis antigens existing in patient's vaginal secretion, using the antiserum raised against the total secretory antigens from T. vaginalis cultures. Two T. vaginalis antigens with molecular weights near 110 KDa have been demonstrated to be useful antigens as the diagnostic markers.

Excessive production of insulin-like growth factor-I by silicotic rat alveolar macrophages

The supernatant of silicotic rat alveolar macrophages can stimulate fibroblast growth. The present study demonstrates that this activity is mainly attributed to insulin-like growth factor-I. Partial purification of the supernatant of alveolar macrophages, which were from silica-exposed 5 to 6-week-old rats, revealed a protein peak (peak 5) eluted from a molecular-sieve HPLC column, corresponding to a MW of 6-9 kDa. Activity assay and radioimmunoassay indicated that this peak is more potent with regard to stimulation of fibroblast growth and has higher insulin-like growth factor-I immunoreactivity, but there was no detectable activity of interleukin-1 or tumor necrosis factor. Quantification of insulin-like growth factor-I also manifests elevated insulin-like growth factor-I levels in silicotic rat bronchoalveolar lavage fluids which tend to increase with prolongation of silica exposure in vivo, but no alteration in insulin-like growth factor-I level can be found in sera. These findings suggest that excessive production of insulin-like growth factor-I by alveolar macrophages locally may play a pivotal role in silica-induced pulmonary interstitial fibrosis.

Catalytic RNA reactions of yeast tRNA(Phe) fragments

We describe 12 new catalytic RNA reactions which are intermolecular variants of the well-known intramolecular Pb(2+)-promoted hydrolysis of yeast tRNA(Phe). Fragments derived from the native yeast tRNA(Phe) which possess the T stem-loop can function as catalysts for the site-specific hydrolysis at p18 of D stem-loop-containing fragments. An initial report described the catalytic cleavage of an unmodified T7 transcript corresponding to the 5' half of tRNA(Phe) by a 3' half-molecule derived from the native tRNA. [Sampson, J. R., Sullivan, F. X., Behlen, L. S., DiRenzo, A. B., & Uhlenbeck, O. C. (1987) Cold Spring Harbor Symp. Quant. Biol. 52, 267-275]. We have investigated the trans reaction further by creating a family of substrate and catalyst RNA molecules by dissection of the native tRNA(Phe) using a combination of chemical and enzymatic methods. A search for cleavage activity in trans was conducted using a combinatorial approach with the available T and D stem-loop-containing fragments. Twelve combinations were found to be catalytic, and initial rates, kcat's, and Km's are reported for each. The kcat's for the reactions differ by approximately 20-fold, whereas Km's vary by only approximately 2-fold. Differences in some of the cleavage rates argue that tertiary interactions present in the intact molecule can be reconstituted in the fragment combinations. Secondary structural features remote from the cleavage site can also affect the apparent cleavage rates. A minimum catalytic complex consisting of a substrate fragment corresponding to nucleotides 1-24 of the native molecule and a catalytic RNA corresponding to 46-76 is identified. This complex is of interest since the transition state for cleavage involves only three helices, with no elements of the anticodon required for cleavage. This is reminiscent of the proposed secondary structure of the hammerhead catalytic RNA cleavage motif.

[Anti-human lung giant cell cancer (PG) effect of human LAK cells in vitro and in nude mice]

Human LAK cells were prepared by culturing normal human peripheral blood mononuclear cells (PBMC) with or without rIL-2 and assayed for T cell surface markers as well as anti-tumor activity against PG in vitro and in nude mice. Although the percentages of T3, T4 and T8 positive cells in rIL-2-activated cells did not differ significantly from those of control cells in vitro, the former showed stronger cytotoxicity than control cells to PG tumor cells in vitro. In vivo, LAK cells completely inhibited the growth of PG tumor in nude mice, whereas PBMC control cells were of no effect. The anti-tumor effect of human LAK cells in nude mice may offer a useful model to study the role of human LAK cells against human tumor in vivo.

Localization of L11 on the Escherichia coli ribosome by singlet-singlet energy transfer

Isolated Escherichia coli ribosomal protein L11 was labeled with maleimidyl derivatives of coumarin or fluorescein at the thiol group of its single cysteine, then reconstituted singly or in pairs with other fluorescently labeled ribosomal components. The characteristics of fluorescence from the labeled protein were studied and its distance to other components was determined by non-radiative energy transfer. The distance between probes on L11 and cysteine residues on other proteins or the 3' end of the ribosomal RNAs were found to be: S1, 7.4-8.3 nm; S21, 7.6 nm; 23S RNA, 6.9 nm; 5S RNA, 7.6 nm; 16S RNA, greater than 8.5 nm. Considered together with previously published results these distances indicate that the location of L11 in the 50S subunit is below the lateral protuberance characterized by L7/L12.

Binding of S21 to the 50S subunit and the effect of the 50S subunit on nonradiative energy transfer between the 3' end of 16S RNA and S21

Escherichia coli ribosomal protein S21 was labeled at its single cysteine group with a fluorescent probe. Labeled S21 showed full activity in supporting MS2 RNA-dependent binding of formylmethionyl-tRNAf to 30S ribosomal subunits. Fluorescence anisotropy measurements and direct analysis on glycerol gradients demonstrate conclusively that labeled S21 binds to 50S ribosomal subunits as well as to 30S and 70S particles. The relative binding affinities are in the order 70S greater than 30S greater than 50S. Other results presented appear to indicate that S21 is bound in the same position on either 50S subunits or 30S subunits as in 70S ribosomes, suggesting that the protein is bound simultaneously to both subunits in the latter. Addition of 50S subunits to 30S particles containing probes on S21 and at the 3' end of 16S RNA caused a decrease in the energy transfer between these points. The results correspond to an apparent change in distance from 51 to 61 A.

Relaxation time, interthiol distance, and mechanism of action of ribosomal protein S1

The two sulfhydryl groups of ribosomal protein S1 from Escherichia coli have been labeled with fluorescent maleimides and the distance between them has been determined by nonradiative energy transfer. This distance was found to be approximately 27 A for both free S1 and S1 bound to 30 S subunits. This value probably represents an upper limit. The position of the fluorescence emission maximum indicates that both sulfhydryl groups are in a relatively hydrophobic environment. When poly(U) is added to labeled S1, either free or in 30 S subunits, the emission maximum shifts to the red by about 3 nm but without a detectable change in the interthiol distance. S1 labeled at one or both of its sulfhydryl groups retains most of its ability to enhance poly(U)-directed polyphenylalanine synthesis. About the same concentration of poly(U) is required to give the maximum shift in fluorescence as is required to give maximum polyphenylalanine synthesis, indicating that S1 binds poly(U) during translation. The peptide initiation inhibitor aurintricarboxylic acid almost completely quenches the fluorescence from either labeled sulfhydryl groups in S1 bound to ribosomes or free in solution. This quenching probably is due to energy transfer from the labeled sulfhydryls to bound aurintricarboxylic acid. Fluorescence anisotropy measurements indicated that the C-terminal domain of S1 is relatively rigid, but retains some independent movement when attached to ribosomes. The overall data are consistent with a model in which a region near the two sulfhydryl groups in the elongated C-terminal domain functions to sequester and bind mRNA to the ribosome during peptide synthesis.