[Clinicopathological features of adult Wilms tumor with BRAF V600E mutation]

Objective: To identify BRAF V600E mutations in adult Wilms tumor (WT) with overlapping histologic features of metanephric adenoma (MA) and to investigate the clinicopathological features of adult WT. Methods: The clinical features of adult WT diagnosed at the Fudan University Shanghai Cancer Center, Shanghai, China from 2012 to 2021 were reviewed. HE-stained slides of all cases were reviewed by 2 expert pathologists. Representative tissues were selected for BRAF V600E immunohistochemical (IHC) staining and gene sequencing. Results: In adult WT with MA-like areas (cohort Ⅰ, n=6), 5 of the 6 cases were composed of epithelial-predominant and were positive for WT-1 and CD56, respectively, and all were positive for CD57. All 6 cases revealed highly variable Ki-67 indices, ranging from 1% in some areas to 60% in others. 5 of the 6 cases harbored a BRAF V600E mutation. All cases in cohort I were followed up for 23 to 71 months, and all survived. In classical adult WT without MA-like areas cohort (cohort Ⅱ, n=13), all 7 cases with available material were negative for BRAF by IHC and none of them had any BRAF mutation. Conclusions: BRAF V600E mutations are frequently present in adult WT with overlapping morphologically features of MA, but not in those without. More importantly, adult WTs with overlapping histologic features of MA may be an intermediate entity between typical MA and WT that may have a favorable prognosis and possible therapeutic targets.

[Analysis on impact of four major non-communicable diseases on life expectancy of local population in Ji'nan, 2015-2020]

Objective: To analyze the impact of malignant neoplasms, cardiovascular diseases, respiratory diseases and diabetes (four major chronic diseases) on the increase of life expectancy of local population in Ji'nan during 2015-2020. Methods: Based on 2015-2020 cause-of-death surveillance information and population data of Ji'nan, we used abbreviated life expectancy table and Arriaga decomposition method to analyze the overall and disease specific contributions of four major chronic diseases to the increase of life expectancy, and the gender and age specific contributions of mortality rates of four major chronic diseases to the increase of life expectancy of local population from 2015 to 2020. Results: Life expectancy of the local population in Ji'nan increased by 1.59 years from 2015 to 2020. The decline in mortality rates of the four major chronic diseases contributed 1.25 years, with a contribution of 78.62%. The life expectancy in men increased by 1.66 years, with a contribution of 1.18 years from the decline in mortality rate of four major chronic diseases, and the life expectancy in women increased by 1.52 years, with a contribution of 1.35 years from the decline in mortality of four major chronic diseases. The declines in the mortality rates of malignant neoplasms, cardiovascular diseases, respiratory diseases and diabetes contributed 0.42, 0.62, 0.20, and 0.01 years to life expectancy, respectively. The decline mortality rate of gastric cancer contributed more to the increase of life expectancy compared with lung cancer. The increase in the mortality rate of hypertensive heart disease resulted in a negative contribution. Asthma and diabetes contributed very little to the increase of life expectancy. Conclusions: The increase in the life expectancy of local population in Ji'nan from 2015 to 2020 was mainly attributed to the decline in mortality of four major chronic diseases. It is necessary to pay close attention to the diseases which contributed very little or even had negative contribution to the increase of life expectancy, such as lung cancer, diabetes and hypertensive heart disease.

[Evaluation of bladder function and sleep patterns in children with primary mono-symptomatic nocturnal enuresis by polysomnography combined with ambulatory urodynamic monitoring]

Objective: To evaluate the bladder function and sleep pattern in the children with primary mono-symptomatic nocturnal enuresis (PMNE) by the polysomnography (PSG) and ambulatory urodynamic monitoring (AUM). Methods: From October 2019 to October 2021, forty-three patients with PMNE were selected as PMNE group from the First Affiliated Hospital of Zhengzhou University and further subdivided into the severe PMNE group (enuresis>4 times/week) and the non-severe PMNE group (enuresis times 4 times/week) according to the severity. The conventional urodynamics (CUD), AUM, and PSG examinations and bladder diary were completed in the PMNE group. The control group consisted of 23 children with normal PSG findings and without the lower urinary tract symptoms. Results: The severe PMNE group included 9 males and 14 females, aged(12.1±3.2)years, and nocturnal enuresis number per week is 6.7±1.7. The non-severe PMNE group included 9 males and 11 females, aged(12.0±3.4)years, and nocturnal enuresis number per week is 2.3±1.0. The incidences of nocturnal polyuria and the reduction in maximum bladder capacity in the PMNE group was 34.9% and 11.6%, respectively. The incidence and frequency of detrusor overactivity (DO) in the severe PMNE group were significantly higher than those in the non-severe PMNE group [78.3% vs 45.0%, (5.5±1.8) times/h vs (3.4±1.0) times/h, respectively, all P<0.05]. It was found by the PSG that the severe PMNE group had significantly higher cortical arousal index, apnea hypopnea index (AHI), and percentage of N1+N2 phase in total sleep time, compared with the control group[(58.6±9.8)% vs (49.3±9.5)%, (9.4±4.4) times/h vs (3.1±1.5) times/h, (2.7±0.9) times/h vs (0.9±0.7) times/h] (all P<0.05). While the sleep efficiency of the severe PMNE group was substantially lower than that of the non-severe PMNE group [(86.4±4.3)% vs (91.0±3.9)%], the cortical arousal index and AHI were significantly greater than those of the non-severe PMNE group[(9.4±4.4) times/h vs (5.7±3.2) times/h, (2.7±0.9) times/h vs (1.9±0.7) times/h] (all P<0.05). In the PMNE group, there were positive correlations between cortical arousal index and nocturnal DO frequency or AHI (r=0.705, 0.765, P=0.001). Conclusions: Children with PMNE have nocturnal bladder dysfunction and abnormal sleep pattern, and there is a certain correlation between them. PSG and AUM are necessary for the evaluation and treatment of children with PMNE.

[Outcomes at discharge of preterm infants born <34 weeks' gestation]

Objective: To investigate the incidence and trend of short-term outcomes among preterm infants born <34 weeks' gestation. Methods: A secondary analysis of data from the standardized database established by a multicenter cluster-randomized controlled study "reduction of infection in neonatal intensive care units (NICU) using the evidence-based practice for improving quality (REIN-EPIQ) study". This study was conducted in 25 tertiary NICU. A total of 27 192 infants with gestational age <34 weeks at birth and admitted to NICU within the first 7 days of life from May 2015 to April 2018 were enrolled. Infants with severe congenital malformation were excluded. Descriptive analyses were used to describe the mortality and major morbidities of preterm infants by gestational age groups and different admission year groups. Cochran-Armitage test and Jonckheere-Terpstra test were used to analyze the trend of incidences of mortality and morbidities in 3 study-years. Multiple Logistic regression model was constructed to analyze the differences of outcomes in 3 study-years adjusting for confounders. Results: A total of 27 192 preterm infants were enrolled with gestational age of (31.3±2.0) weeks at birth and weight of (1 617±415) g at birth. Overall, 9.5% (2 594/27 192) of infants were discharged against medical advice, and the overall mortality rate was 10.7% (2 907/27 192). Mortality for infants who received complete care was 4.7% (1 147/24 598), and mortality or any major morbidity was 26.2% (6 452/24 598). The incidences of moderate to severe bronchopulmonary dysplasia, sepsis, severe intraventricular hemorrhage or periventricular leukomalacia, proven necrotizing enterocolitis, and severe retinopathy of prematurity were 16.0% (4 342/27 192), 11.9% (3 225/27 192), 6.8% (1 641/24 206), 3.6% (939/25 762) and 1.5% (214/13 868), respectively. There was a decreasing of the overall mortality (P<0.001) during the 3 years. Also, the incidences for sepsis and severe retinopathy of prematurity both decreased (both P<0.001). However, there were no significant differences in the major morbidity in preterm infants who received complete care during the 3-year study period (P=0.230). After adjusting for confounders, infants admitted during the third study year showed significantly lower risk of overall mortality (adjust OR=0.62, 95%CI 0.55-0.69, P<0.001), mortality or major morbidity, moderate to severe bronchopulmonary dysplasia, sepsis and severe retinopathy of prematurity, compared to those admitted in the first study year (all P<0.05). Conclusions: From 2015 to 2018, the mortality and major morbidities among preterm infants in Chinese NICU decreased, but there is still space for further efforts. Further targeted quality improvement is needed to improve the overall outcome of preterm infants.

[Pathological features of primary extragonadal germ cell tumor of the prostate with small round blue cell morphology]

Objective: To investigate the clinicopathological features and clinical management of primary extragonadal germ cell tumor of the prostate. Methods: Two cases of primary extragonadal germ cell tumor in the prostate were collected at Fudan University Shanghai Cancer Center, in January and September 2016, respectively. Their pathological features, clinical treatments and follow-up were retrospectively analyzed. Results: The two patients were 41 and 32 years old, respectively, and both presented with obstructive symptoms of the lower urinary tract. Histologically, both cases showed small round blue cells and an invasive growth pattern. The immunohistochemistry (IHC) stains of SALL4, OCT3/4, CD117 and PLAP were all positive, while those of PSA, AR and syn were negative. Moreover, case 1 demonstrated perinuclear dot-like staining for CKpan, which might be a diagnostic pitfall. There was no evidence of disease in other areas via physical examination or radiographic studies. Based on these IHC findings and the morphology, the two cases were diagnosed as primary seminoma of the prostate, which were consequently treated with six cycles of bleomycin, etoposide and cisplatin-based chemotherapy. A complete response was achieved in case 1. Case 2 was followed up and showed tumor recurrence, and progression with elevated tumor marker AFP. The subsequent radical removed specimens of case 2 were finally diagnosed as mixed germ cell tumor of the prostate. Conclusion: As a rare neoplastic entity, primary germ cell tumor of the prostate can show small blue round cell morphology. Pathologically, the morphology of small round blue cells combined with a perinuclear dot-like pattern of CKpan IHC staining may be a diagnostic pitfall. The clinical treatment strategy should be evaluated with consideration of the pathological diagnosis and comprehensive evaluation of the tumor markers.

[Study on the influence of sleeve height and implant length on accuracy of static computer-assisted implant surgery]

Objective: To evaluate the influence of the sleeve lengths and implant lengths on accuracy of static computer-assisted implant surgery (sCAIS). Methods: Twenty-eight models of bilateral mandibular single tooth loss were included. Fifty-five implants were placed under the guidance of sCAIS (Straumann Bone Level 4.1 mm×10 mm). According to the height of metal sleeve of static guide plate, 55 implants were divided into 11 groups (free hand group, 1 mm group, 2 mm group, 3 mm group, 4 mm group, 5 mm group, 6 mm group, 7 mm group, 8 mm group, 9 mm group, 10 mm group), with 5 implants in each group. Eight research models were included. Group with 5 mm sleeve guides were used to place implants of different length, (Straumann Bone Level width 4.1 mm, height was 8 mm, 10 mm and 14 mm), 5 implants in each group. Eighteen patients with mandibular single tooth loss were included in the Department of Oral Implantology, Tianjin Stomatological Hospital from October 2018 to June 2019. There were 10 males and 8 females, 18-46(33.7±7.9) years old. A total of 18 implants were implanted and divided into 3 groups (free hand group, 3 mm group and 5 mm group) with 6 implants in each group. Digital software was used to compare the implant positions before and after implantation. Non-parametric Kruskal-Wallis test or one-way ANOVA were used to analyze the results. Results: There was no significant difference in implant vertical deviation between different sleeve height groups (1-10 mm) and free hand group, but the neck deviation in free hand group[(1.04±0.13) mm] was significantly higher than that in different sleeve height groups (1-10 mm) (P<0.05). The tip deviations of free hand group, 1 mm group and 2 mm group [(1.32±0.43), (0.83±0.10) and (0.78±0.11) mm, respectively] was significantly higher than that of 10 mm group [(0.31±0.14) mm](P<0.05). The angle deviation of free hand group and 1 mm group (3.99°±0.85° and 2.59°±0.69°), respectively] was significantly higher than that of 10 mm group (0.61°±0.03°) (P<0.05). The tip deviations of implants in the 14 mm group [(0.83±0.22) mm] was significantly higher than that in the 8 mm and 10 mm groups [(0.44±0.07) and (0.49±0.06) mm, respectively]. Clinical studies showed that there was no significant difference in neck deviation, tip deviation and angle deviation between 3 mm group and 5 mm group (P>0.05), but deviations were significantly lower than those in free hand group (P<0.05). Conclusions: The length of the sleeves has significant influence on the accuracy of the surgical guide. There was no significant difference in accuracy of the implant guide with 3 mm or 5 mm metal sleeves. The vitro study has some limitations and needs further systematic research.

[Strategy of schistosomiasis elimination and its effects in Jinhu County, Jiangsu Province]

OBJECTIVE

To understand the strategy of schistosomiasis elimination and its effects in Jinhu County, Jiangsu Province.

METHODS

The data of schistosomiasis control in Jinhu County at different stages from 1970 to 2017 were collected and analyzed.

RESULTS

From 1970 to 2017, there were three stages of schistosomiasis control, including transmission control, transmission interruption, and monitoring and elimination stages in Jinhu County. The main measures included Oncomelania hupensis snail control, infectious source control, and health education. A total of area of 290 691.78 hm² was detected in Jinhu County, and the area with snails was 3 420.98 hm². There were 8 729.37 hm² area with snails was controlled. Since 2014, no O. hupensis snails were found. A total of 525 377 person-times were examined for schistosomiasis, with 2 815 schistosomiasis patients identified, and 2 844 person-times were treated by chemotherapy. In addition, 977 cases received the expand chemotherapy. Since 1990, no local schistosome-infected persons were found. In 2017, the awareness rate of schistosomiasis control knowledge and the correct rate of health behavior were increased by 54.59% and 14.23% respectively compared with those in 1992.

CONCLUSIONS

The comprehensive schistosomiasis control measures implemented in Jinhu County at different periods have achieved remarkable outputs and accelerated the schistosomiasis elimination process. However, the precise control measures should be implemented in the future to consolidate the prevention and control achievements.

Low vaspin levels are related to endothelial dysfunction in patients with ankylosing spondylitis

Vaspin is a novel adipocytokine associated with glucose tolerance and chronic inflammation. Some studies reveal that vaspin may be involved in cardiovascular diseases. Our objective was to investigate the relationship between serum vaspin levels and endothelial function in patients with ankylosing spondylitis. One hundred and twenty patients with newly diagnosed ankylosing spondylitis and 100 healthy subjects were studied. Serum vaspin levels were measured with enzyme-linked immunosorbent assay. High resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperemia (flow-mediated dilation, FMD) and after sublingual glyceryltrinitrate. Serum vaspin level in patients was 1.92±1.03 ng/mL, which was significantly lower than that in healthy subjects (2.88±0.81 ng/mL). By dividing the distribution of serum vaspin levels into quartiles, FMD levels increased gradually with the increase of serum vaspin levels in patients (P<0.01). Univariate analysis showed a correlation between vaspin and FMD (r=0.73, P=0.003), low-density lipoprotein cholesterol (r=-0.45, P=0.033), high-density lipoprotein cholesterol (r=0.63, P=0.025), fasting blood glucose (r=-0.79, P=0.006), triglycerides (TG) (r=-0.68, P=0.036), systolic blood pressure (r=-0.35, P=0.021), C-reactive protein (r=-0.67, P=0.011), homeostatic model assessment of insulin resistance (HOMA-IR) (r=-0.77, P=0.023) and erythrocyte sedimentation rate (r=-0.88, P=0.039) in patients. Multivariate analysis indicated that serum vaspin levels were independently associated with FMD, HOMA-IR and TG in patients. Our study found that serum vaspin levels were decreased in patients with ankylosing spondylitis and were associated with FMD levels. Vaspin may serve as an independent marker for detecting early stage atherosclerosis in patients with ankylosing spondylitis.

Osteoblast differentiation of rabbit adipose-derived stem cells by polyethylenimine-mediated BMP-2 gene transfection in vitro

The aim of this study was to examine the efficiency of polyethylenimine-mediated transfection of the human bone morphogenetic protein-2 (BMP-2) gene into rabbit adipose-derived stem cells (ADSCs), and its effect on osteoblast differentiation. Adipose tissue was isolated from the necks of adult Japanese white rabbits and cultured in vitro to obtain ADSCs. Gene delivery of BMP-2 was mediated by polyethylenimine and stable transformants were selected by G-418. The expression of BMP-2 mRNA was confirmed by reverse transcription-polymerase chain reaction, and of the BMP-2 protein by ELISA. Osteocalcin and collagen type I were detected by western blot and by an alkaline phosphatase kit. Alizarin red S stain was also utilized to examine osteogenesis. The non-transfected group was considered as a control. In this study, we successfully derived ADSCs from rabbit adipose tissue. Through passages 3-6, the expression of CD29 and CD44 gradually increased, whereas the expression of CD34 and CD45 gradually decreased. Both mRNA and protein expression of BMP-2 were confirmed following polyethylenimine-mediated BMP-2 gene delivery. In addition, the expression of alkaline phosphatase, osteocalcin, and collagen type I was found to be upregulated and alizarin red S staining was positive in transfected ADSCs, indicating BMP-2-induced osteogenesis. Therefore, this study determined that polyethylenimine was able to mediate BMP-2 gene delivery and induce osteogenic differentiation of ADSCs.

Development of EST-SSR markers in the relict tree Davidia involucrata (Davidiaceae) using transcriptome sequencing

Davidia involucrata, reputed to be a "living fossil" in the plant kingdom, is a relict tree endemic to China. Extant natural populations are diminishing due to anthropogenic disturbance. In order to understand its ability to survive in a range of climatic conditions and to design conservation strategies for this endangered species, we developed genic simple sequence repeats (SSRs) from mRNA transcripts. In total, 142,950 contigs were assembled. Of these, 30,411 genic SSR loci were discovered and 12,208 primer pairs were designed. Dinucleotides were the most common (77.31%) followed by trinucleotides (16.44%). Thirteen randomly selected primers were synthesized and validated using 24 individuals of D. involucrata. The markers displayed high polymorphism with the number of alleles per locus ranging from 3 to 12 and the observed and expected heterozygosities ranging from 0.083 to 1.0 and 0.102 to 0.69, respectively. This large expressed sequence tag dataset and the novel SSR markers will be key tools in comparative studies that may reveal the adaptive evolution, population structure, and resolve the genetic diversity in this endangered species.

Development of expressed sequence tag-based microsatellite markers for the critically endangered Isoëtes sinensis (Isoetaceae) based on transcriptome analysis

Isoëtes sinensis is a critically endangered quillwort. To facilitate studies on the conservation genetics of this species, we developed expressed sequence tag-simple sequence repeat (EST-SSR) markers. A total of 50,063 unigenes were predicted by transcriptome sequencing, 5294 (10.6%) of which significantly matched 3011 Gene Ontology annotations and 2363 were assigned to Kyoto Encyclopedia of Genes and Genomes metabolic pathways. Most of these (2297) were involved in metabolism. A total of 1982 SSR motifs were identified, with trinucleotides being the dominant repeat motif, and 1438 (72.6%) SSR primers were designed. Eighteen randomly selected primer pairs were used to genotype 24 I. sinensis accessions, which confirmed the suitability of these novel markers for molecular studies of I. sinensis. The heterozygosity index value ranged between 0.0799 and 0.9106, while the Shannon-Wiener diversity index value ranged between 0.1732 and 2.5589. The EST-SSRs reported in this study are linked to genic sequences, and are therefore ideal for investigating the evolutionary history of I. sinensis. These markers, together with the large EST dataset generated in this study, will greatly facilitate conservation genetic studies of I. sinensis.

Development of microsatellite markers in Hagenia abyssinica (Bruce) J.F. Gmel, an endangered tropical tree of eastern Africa, using next-generation sequencing

Hagenia abyssinica (Bruce) J.F. Gmel is an endangered tree species endemic to the high mountains of tropical Africa. We used Illumina paired-end technology to sequence its nuclear genome, aiming at creating the first genomic data library and developing the first set of genomic microsatellites. Seventeen microsatellite markers were validated in 24 individuals. The average number of alleles per locus was 7.6, while the observed and expected heterozygosities ranged from 0.000 to 0.958 and from 0.354 to 0.883, respectively. These polymorphic markers will be used as tools for further molecular studies to facilitate formulation of appropriate conservation strategies for this species.

Development and characterization of microsatellite loci in Brasenia schreberi (Cabombaceae) based on the next-generation sequencing

To understand genetic variability of the endangered aquatic herb Brasenia schreberi (Cabombaceae), we describe 31 microsatellite markers obtained using next-generation sequencing. A total of 24 individuals from the population of Jackson Lake, USA, were genotyped for each marker. Twenty-eight markers were polymorphic. The number of alleles per locus ranged from 1 to 9; the observed and expected heterozygosities ranged from 0 to 1 and from 0 to 0.751, respectively. These markers should be useful tools for genetic variation and conservation studies of B. schreberi.

Development of microsatellite markers in the tetraploid fern Ceratopteris thalictroides (Parkeriaceae) using RAD tag sequencing

To understand the genetic variability of the tetraploid fern Ceratopteris thalictroides (Parkeriaceae), we described 30 polymorphic microsatellite markers obtained using the restriction site-associated DNA (RAD) tag sequencing technique. A total of 26 individuals were genotyped for each marker. The number of alleles per locus ranged from 4 to 10, and the expected heterozygosity and the Shannon-Wiener index ranged from 0.264 to 0.852 and 0.676 to 2.032, respectively. Because these 30 microsatellite markers exhibit high degrees of genetic variation, they will be useful tools for studying the adaptive genetic variation and sustainable conservation of C. thalictroides.

[Frequency and clinical relevance of rapidly growing mycobacterium isolated from respiratory samples]

OBJECTIVE

To assess the frequency and clinical relevance of rapidly growing mycobacterium (RGM) isolates in a tuberculosis referral center in Beijing, China.

METHODS

All isolates were identified by using targeted gene sequencing. RESULTS of species identification for 228 nontuberculous Mycobacterium (NTM) isolates from respiratory samples were analyzed, and available medical files of patients from whom NTM were isolated were reviewed retrospectively. Diagnostic criteria for RGM pulmonary disease issued by the American Thoracic Society (ATS) were used to determine clinical relevance.

RESULTS

Isolates of Mycobacterium abscessus (M.abscessus) and Mycobacterium fortuitum (M.fortuitum) accounted for 28.9% (66 isolates) and 8.8% (20 isolates)of NTM isolates, respectively. Sixty-six M. abscessus isolates from 32 patients had evaluable medical files, including 28 cases diagnosed as definite M. abscessus lung disease, and 4 as probable M. abscessus lung disease. Eight M. fortuitum isolates from 8 cases had evaluable medical files, and all of them were diagnosed as unlikely lung disease. Mycobacteria Growth Indicator Tube (MGIT) was more effective to diagnose M. abscessus lung disease, as compared with Lowestein-Jensen medium (23/24 vs 18/28).

CONCLUSIONS

RGM is a common NTM in our institute. M. abscessus is mostly associated with RGM lung disease, but M. fortuitum is not.

c-Myb binds to a sequence in the proximal region of the RAG-2 promoter and is essential for promoter activity in T-lineage cells

The RAG-2 gene encodes a component of the V(D)J recombinase which is essential for the assembly of antigen receptor genes in B and T lymphocytes. Previously, we reported that the transcription factor BSAP (PAX-5) regulates the murine RAG-2 promoter in B-cell lines. A partially overlapping but distinct region of the proximal RAG-2 promoter was also identified as an important element for promoter activity in T cells; however, the responsible factor was unknown. In this report, we present data demonstrating that c-Myb binds to a Myb consensus site within the proximal promoter and is critical for its activity in T-lineage cells. We show that c-Myb can transactivate a RAG-2 promoter-reporter construct in cotransfection assays and that this transactivation depends on the proximal promoter Myb consensus site. By using a chromatin immunoprecipitation (ChIP) strategy, fractionation of chromatin with anti-c-Myb antibody specifically enriched endogenous RAG-2 promoter DNA sequences. DNase I genomic footprinting revealed that the c-Myb site is occupied in a tissue-specific fashion in vivo. Furthermore, an integrated RAG-2 promoter construct with mutations at the c-Myb site was not enriched in the ChIP assay, while a wild-type integrated promoter construct was enriched. Finally, this lack of binding of c-Myb to a chromosomally integrated mutant RAG-2 promoter construct in vivo was associated with a striking decrease in promoter activity. We conclude that c-Myb regulates the RAG-2 promoter in T cells by binding to this consensus c-Myb binding site.

Cryopreservation and transplantation of dog trachea

In order to meet the need of trachea transplantation for clinical application, it is important to research the methods of cryopreservation and transplantation of trachea. By the thermal analyses and thermal control techniques, combined with electron microscopy, the effects of cooling and warming rates with different concentrations of cryoprotective agents were studied. Also the transplantation technique was studied, eighty five percent (17/20) of the dogs were survival after the transplantation with cryopreserved tracheas.

Human immunodeficiency virus (HIV) envelope binds to CXCR4 independently of CD4, and binding can be enhanced by interaction with soluble CD4 or by HIV envelope deglycosylation

Chemokine receptor CXCR4 (also known as LESTR and fusin) has been shown to function as a coreceptor for T-cell-tropic strains of human immunodeficiency virus type 1 (HIV-1). We have developed a binding assay to show that HIV envelope (Env) can interact with CXCR4 independently of CD4 but that this binding is markedly enhanced by the previous interaction of Env with soluble CD4. We also show that nonglycosylated HIV-1(SF-2) gp120 or sodium metaperiodate-treated oligomeric gp160 from HIV-1(451) bound much more readily to CXCR4 than their counterparts with intact carbohydrate residues did.

Induction of pulmonary allergic responses by antigen-specific Th2 cells

The development of pulmonary allergic responses was examined in mice following pulmonary transfer of Ag (conalbumin)-specific Th2 cells. The levels of serum-specific IgE, cellular infiltrates, airway mucus goblet cells, and airway responsiveness were analyzed and compared with those in Ag-sensitized and -challenged mice. Pulmonary transfer of the conalbumin-specific Th2 clone (D10) induced, in an Ag-specific manner, high levels of the Th2 cytokines IL-4 and IL-5 in the bronchoalveolar lavage fluids and mucosal eosinophils, concomitant with an increase in airway responsiveness. The D10 cell-induced responses were seen in the absence of serum specific IgE. In the presence of Ag, the transferred D10 cells not only remained in the lungs, but also increased in number 72 h post-cell transfer. Although significantly higher levels of IL-4 and IL-5 in the bronchoalveolar lavage fluids were found in D10-transferred mice, the levels of pulmonary eosinophilia, mucus goblet cells, and airway responsiveness were significantly lower than those in Ag-sensitized and -challenged mice. These results demonstrate that although Ag-specific activation of Th2 cells at mucosal sites is able to mediate the recruitment of eosinophils and the subsequent induction of airway hyper-responsiveness, the more severe pulmonary allergic responses were observed only in mice sensitized and challenged with Ag.

The evaluation of developmental toxicity of chemicals exposed occupationally using whole embryo culture

The purpose of this study was to employ the whole embryo culture (WEC) system to evaluate the developmental toxicity of industrial chemicals. Five chemicals including lead, cadmium, vinyl chloride, 1,2-dichloroethan, and carbon disulphide were tested in our laboratory both in vitro and in vivo (except lead). In vitro studies showed that cadmium and lead were teratogenic in the rat; whilst carbon disulphide, 1,2-dichloroethan and vinyl chloride mainly induced embryo growth retardation. The in vitro effects on development of the five industrial chemicals were similar to the effects in vivo. The in vitro effects were studied by three different exposure routes, direct exposure--chemicals added to the culture medium; indirect exposure--serum prepared from treated rats then used as culture medium, and pre-exposure--embryos treated maternally then explanted into control (untreated) culture medium. Comparing these three different exposure routes suggests that the last exposure route is the most effective when using WEC to evaluate developmental toxicity of industrial chemicals. The effects on embryo development of culturing in sera prepared from subjects occupationally exposed to antineoplastic drugs (ADs) was also tested by the WEC system. Embryos were cultured with human serum that was thought to contain ADs or ADs' metabolic materials (serum taken from nurses routinely handling ADs), to evaluate the effects of ADs on embryo development. Embryos (9.5-day) cultured with serum from 11 female nurses who had been handling ADs for 2-17 years in the oncology department all survived, but showed slight growth retardation. Embryos cultured with serum from 30 healthy and unexposed people served as controls and embryo development in their serum was normal.

Activin inhibits basal and androgen-stimulated proliferation and induces apoptosis in the human prostatic cancer cell line, LNCaP

LNCaP cells, derived from an androgen-sensitive cell line widely employed as an in vitro model of human prostate cancer, have been shown to express activin receptors. Activin is a local regulator of cellular growth, appears to play a key role in mesoderm induction and differentiation during development, and has been implicated in gonadal tumorigenesis. Follistatin, a monomeric glycoprotein that specifically binds and neutralizes activin, is often coexpressed with activin and, thus, modulates the autocrine/paracrine biological activity of this potent growth factor. We tested the hypothesis that LNCaP growth is modulated by the activin/follistatin system. Recombinant human activin A inhibited [3H]thymidine incorporation in a dose-dependent fashion with an ED50 of approximately 0.43 +/- 0.3 nM. Activin (0.1-3 nM) also inhibited dihydrotestosterone (DHT)-stimulated [3H]thymidine incorporation in LNCaP cells. Similarly, recombinant human inhibin A inhibited LNCaP proliferation, but was only 1/100th as potent as activin. Furthermore, activin (3 nM) induced a 3-fold increase in the extent of labeling of low mol wt DNA fragments typical of apoptosis. Activin-induced apoptosis was also indicated by an increase in the number of cells with reduced DNA content, as measured by flow cytometry of activin-treated cells. Both activin-mediated inhibition of cell proliferation and induction of apoptosis could be completely blocked by recombinant human follistatin. Based upon these results using an in vitro model, we speculate that activin functions locally to oppose androgen-driven cell proliferation and, thus, is a key factor controlling prostate growth. Reduced activin biosynthesis, increased follistatin secretion, or signaling defects in the activin receptor system should be further investigated in future studies as potential mechanisms underlying enhanced androgen-independent growth of human prostate cancer cells.

A two-site monoclonal antibody immunoradiometric assay for human follistatin: secretion by a human ovarian teratocarcinoma-derived cell line (PA-1)

The follistatin/activin/inhibin system increasingly appears to have important growth and differentiating effects in a variety of cell types, including cancer. We have developed a two-site immunoradiometric assay for measurement of human follistatin using two monoclonal antibodies against recombinant human follistatin. This cloned protein donor assay is sensitive (0.5 ng/mL), specific for free human follistatin, and precise (<5% within assay coefficient of variation). Using this assay, native human follistatin could be measured in human pituitary extracts, follicular fluid, and granulosa-luteal cell-conditioned medium. To identify and characterize human follistatin secreted by ovarian cancer cells, we screened five human ovarian carcinoma cell lines currently available from the American Type Culture Collection (Rockville, MD). One of these, a cell line derived from a teratocarcinoma (designated PA-1, American Type Culture Collection, CRL1572), secreted large (3 microg/10(6) cells per 24 h) quantities of immunoreactive follistatin constituitively. Increasing volumes of conditioned medium from these cultured cells generated response curves parallel to those of recombinant human follistatin 288 reference protein, human follicular fluid, or culture medium from human granulosa-luteal cells. Secretion of follistatin by PA-1 cells was time and cell-number dependent with 297.9 +/- 15.2, 654 +/- 29.8, and 940 +/- 49.1 ng follistatin secreted over 24 h by 1 x 10(5), 2 x 10(5), and 3 x 10(5) cells, respectively. Western and ligand blot analysis revealed that the immunoreactive follistatin secreted by PA-1 cells and isolated by sulfate-cellufine chromatography was identical to the molecular weight variants (32,000 and 35,000 Mr) of recombinant human follistatin 288. PA-1 cell-conditioned medium suppressed basal secretion of FSH by cultured rat anterior pituitary cells in a dose-dependent fashion. This follistatin bioactivity was completely removed by adsorption with either solid-phase monoclonal antifollistatin or a dextran-sulfate chromatography gel. Because activin suppressed the proliferation of PA-1 cells, secretion of bioactive follistatin may represent an autocrine mechanism opposing activin to maintain the rapid growth rate of PA-1 cells. These observations demonstrate that the ovarian teratocarcinoma cell line, PA-1, secretes considerable amounts of human follistatin that is biologically active, capable of binding human activin, and antigenically similar to recombinant human follistatin 288. The monoclonal antibodies and two-site assay reported herein should be useful in assessing the regulation of follistatin secretion and as a diagnostic tool, especially if follistatin measurements prove to be a marker for some ovarian cancers.

Characterization of inhibin/activin subunit, follistatin, and activin type II receptors in human ovarian cancer cell lines: a potential role in autocrine growth regulation

Although ovarian cancer is the most common gynecological malignancy with a relatively poor 5-yr survival record, the mechanism(s) by which these tumors arise is not well understood. A role for inhibins and activins in regulating this transformation is suggested by the detection of circulating alpha or dimeric inhibin in some patients with ovarian cancer and by the alpha inhibin knockout mouse, in which development of gonadal tumors in 100% of homozygotes is associated with greatly elevated activin levels. To develop diagnostic tools with greater specificity for ovarian cancers, the present study was targeted at characterizing the biosynthetic capacity of the epithelial ovarian cancer cell lines from the American Type Culture Collection with respect to inhibin, activin, the related activin-binding protein follistatin (FS), and activin receptor type II. In addition, the functional capacity of this system was investigated by examining the ability of activin and FS to modulate cellular proliferation. All six cell lines contained abundant messenger RNA (mRNA) for activin receptor type II, but no inhibin alpha-subunit mRNA was detected in any cell line. Two cell lines contained mRNA for activin beta B-subunit (CaOV4 and SKOV3), one cell line contained beta A-subunit mRNA (SW626), and one cell line contained both (ES2); the latter also contained FS mRNA. FS mRNA was detected in another cell line (PA-1) that contained no detectable activin beta-subunit mRNA. Finally, one cell line (CaOV3) contained neither beta-subunit nor FS mRNA. Protein secretion was also examined. Consistent with the mRNA studies, the two cell lines containing FS mRNA secreted FS (PA-1 and ES2 cells), whereas three of the remaining lines secreted activin (A or B). In the cell line containing neither FS nor beta-subunit mRNA, no FS or activin could be detected. Finally, none of the cell lines secreted detectable immunoreactive inhibin. The effects of exogenous activin and FS on cellular proliferation were examined in these cell lines. No response was detected in the two cell lines that secreted FS (PA-1 and ES2). For the four cell lines not synthesizing FS, treatment with activin (1-100 ng/ml) resulted in an increase, whereas FS treatment (1-100 ng/ml) resulted in a decrease in cellular proliferation, as determined by [3H]thymidine incorporation. The response to activin correlated negatively with endogenous activin production, suggesting that autocrine activin production may be involved with cell proliferation. The differential expression and production of inhibin/activin subunits, activin receptors, and follistatin as well as the range of responses to exogenous activin among six ovarian epithelial cancer cell lines suggest that this family of hormones may be important in regulating cell proliferation in the ovary. Whether primary tumors have the same profile and the degree to which these results can be generalized to additional forms of ovarian cancer remain to be determined.

Follistatin-activin complexes in human serum and follicular fluid differ immunologically and biochemically

Follistatin (FS) is the principle high affinity activin-binding protein in tissues such as the pituitary and ovary as well as in serum. In addition, the activin-binding peaks identified after gel filtration of serum or human follicular fluid (hFF) exhibited high affinity and low reversibility binding kinetics, with higher concentrations in hFF than serum. This extremely low reversibility was also observed for recombinant human follistatin 288 (rhFS288) under a variety of incubation conditions, further supporting the identification of the serum and hFF activin-binding proteins as FS. Using enhanced resolution gel filtration, immunoprecipitation with monoclonal antibodies to rhFS288, and sulfated carbohydrate binding, activin-FS complexes in hFF and serum differed. The activin-FS complex in hFF elutes at approximately 200-300 kDa, is immunoprecipitated by anti-hFS288 monoclonal antibodies, and binds to sulfate Cellufine matrix, all characteristics similar to those of recombinant human FS288. In contrast, the activin binding peak in human serum elutes at an apparent Mr of 60-70 kDa, is no precipitated by anti-rhFS288 monoclonal antibodies, and is weakly bound by sulfate Cellufine matrix, characteristics shared by rhFS315 conditioned medium. As the forms of FS that bind sulfate-containing matrices also bind to cell surface proteoglycans, the molecular differences reported here for serum and hFF activin-binding proteins have implications for potential tissue-specific forms of FS that may well have distinct biological functions.

Serum follistatin levels in women: evidence against an endocrine function of ovarian follistatin

Follistatin is a monomeric protein first identified in and isolated from ovarian follicular fluid. Evidence that follistatin might be an ovarian endocrine hormone functioning in a negative feedback fashion to modulate pituitary FSH production is based primarily on in vitro experiments. To examine the possible role of follistatin as an endocrine agent in vivo, we sought to relate circulating levels of follistatin to ovarian activity in women. Therefore, we developed a specific and sensitive homologous RIA using antiserum generated against recombinant human follistatin for the measurement of total follistatin in the presence or absence of activin. Follistatin was measured quantitatively (106 +/- 6% recovery) using calibration standards ranging from 0.4-25 ng/tube and up to 400 microL/tube serum. Furthermore, all of the endogenous follistatin measured in human serum could be removed by adsorption to activin-coated plates. Using this homologous RIA, human follicular fluid (100-600 ng/mL; n = 75) contained 3-150 times more follistatin than serum (4-35 ng/mL), an observation consistent with the notion that serum follistatin originates from the gonad. However, further studies of follistatin levels across the normal menstrual cycle (mean +/- SE, 8.09 +/- 0.73; n = 72 daily samples from 4 women), in pregnant women (17.49 +/- 1.34; n = 8), in daily samples from 20 women undergoing ovarian stimulation by exogenous FSH (9.90 +/- 0.62; n = 119), in postmenopausal women including two ovariectomized individuals (9.57 +/- 0.43; n = 8), and in GnRH-deficient women (9.85 +/- 0.50; n = 6) failed to support the hypothesis that serum levels of follistatin reflect ovarian activity in women. Levels of follistatin measured in serum collected across normal menstrual cycles did not fluctuate. However, the roughly nanomolar concentrations of follistatin measured suggest a physiological role for this protein. Follistatin at nanomolar concentrations may be capable of binding and inactivating circulating activin and perhaps in this way limiting the biological activity of activin to local autocrine or paracrine mechanisms. Measurement of peripheral levels of follistatin apparently represents only a first, albeit crucial, step in the study of the physiological significance of this protein in human reproduction.

[Variation in extracellular/intracellular Ca2+ does not affect tyrosine (Tyr) suppressive effect on hCG-induced progesterone production by rat corpus luteal cells in vitro]

Ovaries of immature female rats primed with PMSG-hCG were digested with collagenase-DNAase solution to obtain the corpus luteal cell suspensions. After pre-incubation for 1 h, luteal cell suspensions were then incubated with different factors for 2 h. The progesterone contents in the incubates were measured by RIA. It was demonstrated that high Ca2+/high K+/A23187 significantly enhanced both the basal or hCG-induced progesterone production by rat luteal cells. To the contrast, decreased Ca2+ concentration in medium/EGTA/verapamil had inhibitory effect on progesterone production in the presence of hCG. Tyr had suppressive effect on hCG-induced progesterone production. but not in the presence of high Ca2+/high K+/A23187. The present study suggested that progesterone production by luteal cells of rat is influenced by concentration. Yet, variation in extra/intra-cellular Ca2+ does not affect Tyr suppressive effect on hCG-induced progesterone production. It seems that progesterone production by calcium and hCG occurs through two different mechanisms.

[Depth of getting qi in clinical practice]

Based on the type of build being fat, medium and thin to determine the depth of getting Qi (DGQ) in acupoints, and based on the aforesaid three types of build to verify the difference of DGQ of neck, trunk, upper-limb and lower limb with T test. The result showed that the DGQ of fat man group was deeper, the DGQ of thin man group was more superficial (P < 0.01), the DGQ of neck was more superficial than that of trunk, upper and lower limb, and the standard deviation (SD) of neck DGQ was +/- 0.1 cm, that of trunk, upper and lower limbs was +/- 0.2cm. Following finding has been observed, the DGQ of patient with nervousness and allergic constitution showed more superficial, while the DGQ of cancer and apoplexy patients showed deeper than that of ordinary patients.

Comparative observation of the changes in serum lipid peroxides influenced by the supplementation of vitamin E in burn patients and healthy controls

A microfluorescence analytical method was used to determine the contents of serum lipid peroxides and vitamin E in 35 severely burned patients, among whom 18 had been given vitamin E, and in 113 healthy blood donors. A comparative survey showed that the serum vitamin E decreased most significantly from days 6 to 8 postburn in both groups of burned patients, while the concomitant serum lipid peroxides increased significantly and reached a peak value. In control patients, the serum vitamin E levels were lower and lipid peroxides higher than those of healthy people (P less than 0.05) from days 20 to 22 postburn. At this time in the vitamin E-treated patients, the serum vitamin E levels increased and lipid peroxides decreased to the levels of healthy people (P greater than 0.05). Therefore, appropriate supplementation with vitamin E in burn patients is necessary.

Chronic inhibitory effect of follicle-stimulating hormone (FSH)-suppressing protein (FSP) or follistatin on activin- and gonadotropin-releasing hormone-stimulated FSH synthesis and secretion in cultured rat anterior pituitary cells

The effects of bovine FSH-suppressing protein (FSP) or follistatin on activin- and GnRH-stimulated FSH synthesis and secretion have been studied using cultured pituitary cells from adult male Sprague-Dawley rats. Exposure to FSP (0.001-10 nM) for 3 days dose-dependently suppressed basal FSH secretion (IC50 = 146 +/- 21 pM., mean +/- SE), cellular content (IC50 = 269 +/- 8 pM) and total FSH (IC50 = 181 +/- 25 pM), with no effect on LH. Activin (0.3 nM) increased FSH secretion 2.1-fold, cellular content 1.3-fold, and total FSH 1.9-fold during a 3-day incubation, but these increases were dose-dependently inhibited by concomitant treatment with 35-kDa bovine FSP (0.1-3 nM), with complete inhibition occurring at concentrations between 1 and 3 nM. The 31- and 39-kDa forms of bovine FSP also antagonized the actions of activin. GnRH (1 nM) increased FSH secretion 1.8-fold and total FSH 1.6-fold during a 3-day incubation, effects that were dose-dependently inhibited by concomitant treatment with 35-kDa bovine FSP. The highest tested concentration of FSP (3 nM) suppressed GnRH-stimulated FSH secretion and total FSH to 59 and 57%, respectively, of the levels found in untreated cultures. All three forms of bovine FSP produced a significant inhibition of FSH secretion and total FSH stimulated by GnRH. FSP also suppressed FSH secretion and total FSH in response to activators of protein kinase C including 100 nM phorbol 12-myristate 13-acetate (43 and 59%, respectively) and 100 nM mezerein (40 and 60%, respectively). Finally, treatment of cultured pituitary cells with 35-kDa FSP at 1 and 3 nM for 3 days resulted in 21 and 24% decreases in GnRH binding sites, respectively. It is concluded that (i) FSP inhibits not only the secretion but also the synthesis of FSH induced by activin and GnRH in long-term culture, and (ii) FSP may cause its inhibitory effects on GnRH by suppression of the protein kinase C system, and possibly by reduction of GnRH binding sites.

Acute inhibitory effect of follicle-stimulating hormone-suppressing protein (FSP) on gonadotropin-releasing hormone-stimulated gonadotropin secretion in cultured rat anterior pituitary cells

Follicle-stimulating hormone (FSH)-suppressing protein (FSP) or follistatin, a novel gonadal glycoprotein hormone, has been shown to have chronic inhibitory effects on the secretion of both FSH and luteinizing hormone (LH) in response to gonadotropin-releasing hormone (GnRH) in vitro. The present study was designed to investigate the acute effects of bovine FSP on GnRH-stimulated gonadotropin secretion and to examine the potential subcellular sites of this action of FSP using cultured pituitary cells. Anterior pituitaries from adult male Sprague-Dawley rats were enzymatically dispersed and cultured for 48 h, after which the cells were treated with bovine FSP for 6 h, followed by a 4 h stimulation with secretagogues in the continued presence of FSP. Results showed that the 35 kDa form of bovine FSP (0.1-3 nM) dose-dependently suppressed GnRH-stimulated FSH and LH secretion, with inhibition of 38 and 25%, respectively, at 3 nM. In addition, FSP suppressed gonadotropin secretion in response to activators of protein kinase C (phorbol 12-myristate 13-acetate (PMA) and mezerein) and a calcium ionophore (A23187). However, FSP had no effect on gonadotropin secretion evoked by melittin, an activator of phospholipase A2. Furthermore, 35 kDa bovine FSP did not compete with GnRH for GnRH binding sites in a direct competition study and treatment of cultured pituitary cells with FSP (0.1-3 nM) for 10 h did not alter the number of GnRH binding sites on the cell membranes. Finally, similar inhibitory effects on gonadotropin secretion in response to GnRH, PMA and mezerein were obtained with the 31 and 39 kDa forms of bovine FSP, each at a concentration of 1 nM. We conclude from the present study that FSP acutely inhibits GnRH-stimulated gonadotropin secretion in cultured pituitary cells, and that FSP exerts its action beyond the GnRH receptor, possibly by affecting the protein kinase C and/or the calcium-calmodulin systems.

Effect of inhibin on activators of protein kinase-C and calcium-mobilizing agents which stimulate secretion of gonadotropins in vitro: implication of a postgonadotropin-releasing hormone receptor effect of inhibin on gonadotropin release

To further characterize the subcellular mechanisms by which inhibin suppresses GnRH-stimulated gonadotropin release, anterior pituitary cells from adult male Sprague-Dawley rats were treated on day 2 of culture with or without purified 31-kDa bovine inhibin (1-300 pM) for a further 3 days. On day 5, the pretreated cells were washed and incubated in the absence or presence of various secretagogues for 4 h. At the end of the stimulation, the media were saved, and cells were lysed for measurement of both extracellular and intracellular FSH and LH by specific RIAs. Released hormone was expressed as the proportion of total (released plus intracellular) hormone that was available for release in each case. This manipulation of the data corrects for the differential effect of the inhibin pretreatments to suppress intracellular FSH before the stimulation period. Pretreatment for 3 days with inhibin suppressed the proportions of FSH and LH released during 4 h in response to 1) phorbol 12-myristate 13-acetate (100 nM), an activator of protein kinase-C, by maxima of 48% and 53% with inhibin median inhibitory concentrations (IC50) of 17 and 18 pM, respectively; 2) mezerein (100 nM), another type of activator of protein kinase-C, by maxima of 49% and 50% with inhibin IC50 of 19 and 20 pM, respectively; 3) high extracellular K+ (60 mM) by 42% (P less than 0.01) and 38% (P less than 0.01), respectively, with 130 pM inhibin; 4) the calcium ionophore, A23187 (100 microM) by maxima of 54% and 56% with IC50 of 18 and 17 pM, respectively; and 5) GnRH (10 nM) by maxima of 52% and 53% with IC50 of 18 and 19 pM, respectively. However, inhibin had no effect on the proportional release of gonadotropin induced by melittin, an activator of phospholipase-A2. Finally, inhibin had no effect on ACTH release either under basal conditions or in response to CRF (10 nM), phorbol 12-myristate 13-acetate (100 nM), or A23187 (100 microM). We conclude that inhibin suppresses the stimulated release of hormones from gonadotrophs in part by a mechanism common to both gonadotropins that is independent of the previously described inhibitory effect of inhibin on the GnRH receptor. The results are consistent with an action at a site(s) beyond the GnRH receptor, such as protein kinase-C and calmodulin.

Inhibitory effect of pure 31-kilodalton bovine inhibin on gonadotropin-releasing hormone (GnRH)-induced up-regulation of GnRH binding sites in cultured rat anterior pituitary cells

Primary cultures of enzymatically dispersed rat anterior pituitary cells were used to examine the effect of pure 31 kilodalton bovine inhibin on GnRH-induced up-regulation of GnRH binding sites. After 2 days in culture, the cells were exposed to stimuli with or without test substances for 10 h, followed by evaluation of GnRH binding sites using iodinated GnRH-A (Buserelin) as tracer. Inhibin suppressed GnRH-induced up-regulation of GnRH binding sites in a dose-dependent manner with an IC50 of 0.13 U/ml (5.5 pM). The inhibin-related peptides transforming growth factor-beta, and Müllerian inhibitory substance had no detectable effect (stimulatory or inhibitory), suggesting that the action is specific to inhibin. In addition, inhibin inhibited the calcium ionophore A23187-induced up-regulation of GnRH binding sites, indicating that this effect of inhibin can occur, at least in part, at a stage subsequent to Ca2+ mobilization. Inhibin did not compete with iodinated GnRH-A for GnRH binding sites. In conclusion, pure 31 kilodalton bovine inhibin suppressed GnRH-induced up-regulation of GnRH binding sites in cultured rat anterior pituitary cells, providing direct evidence that inhibin modulates delayed actions of GnRH.

Effect of purified 31K bovine inhibin on the specific binding of gonadotropin-releasing hormone to rat anterior pituitary cells in culture

The mechanism by which inhibin decreases the responsiveness of the pituitary gonadotroph to GnRH in terms of secretion of gonadotropins is largely unknown. We studied the effect of pure 31K bovine inhibin on the specific binding of GnRH to rat anterior pituitary cells in culture using iodinated Buserelin as tracer. Results showed that treatment of cultured anterior pituitary cells from adult male rats with inhibin (0-30 U/ml) for 72 h decreased Buserelin binding in a dose-dependent manner. In the presence of a maximally inhibiting dose of manner. In the presence of a maximally inhibiting dose of inhibin, Buserelin binding decreased progressively with time, reaching a minimum of 42% of the control value after 3 days. Exposure of pituitary cells for 3 days to the inhibin-related peptides transforming growth factor-beta (up to 400 pM) and Müllerian inhibitory substance (up to 100 nM) did not decrease binding of Buserelin, suggesting that the effect was specific to inhibin. Inhibin did not compete with iodinated Buserelin for GnRH-binding sites when they were added to the assay tube simultaneously. In addition, treatment with inhibin halved the number, but did not change the affinity, of GnRH-binding sites and had no effect on either cell number of cell viability. It is concluded that the reduction by inhibin of rat gonadotroph responsiveness to GnRH may be partly related to a decrease in the number of GnRH receptors on the cell surface.