[Analysis of healthy life expectancy and related socioeconomic influencing factors among the middle-aged and elderly in China, the United States, and the European Union].

Objective: To calculate and compare the healthy life expectancy (HLE) of the middle-aged and elderly in China, the United States, and developing and developed countries in the European Union(EU) and analyze the impact of socioeconomic factors on HLE in different countries or regions. Methods: Four surveys from 2010 to 2019 were brought into the research. The data were collected from the China Health and Retirement Longitudinal Study, Health and Retirement Study, and the Survey of Health, Ageing and Retirement in Europe. Developed and developing countries in the EU were divided into two groups for calculation. Education level, total family wealth, and work retirement status were selected to measure socioeconomic status, and activities of daily living were used as health status indicators. We used the multi-state life cycle table method to calculate the transition probability between different health states and estimate life expectancy and HLE. Results: A total of 69 544 samples were included in the study. In terms of age, the middle-aged and elderly in the United States and developed countries of the EU have higher HLE in all age groups. In terms of gender, only Chinese women have lower HLE than men. Regarding socioeconomic factors, the middle-aged and elderly with higher education levels and total family wealth level have higher HLE. In China, working seniors have higher HLE, while for USA women and developed countries of the EU, retired or unemployed seniors have higher HLE. Conclusions: Demographic and socioeconomic factors impact HLE in different countries or regions. China should pay more attention to the health of women and the middle-aged and elderly retired with lower education and less total family wealth.

Prognostic value of peripheral blood markers in patients with myositis-associated interstitial lung diseases.

Objectives: The aim of this study was to investigate the association between survival of anti-MDA5 autoantibody-positive/negative patients with myositis-associated interstitial lung disease (MA-ILD) and neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), C-reactive protein-albumin ratio (CAR), and erythrocyte sedimentation rate-albumin ratio (EAR).Method: The study included 104 patients diagnosed with MA-ILD between January 2017 and February 2019 at the First Affiliated Hospital, University of Science and Technology of China. The clinical and laboratory results were compared between survivors and non-survivors in anti-MDA5 autoantibody-positive and anti-MDA5 autoantibody-negative patients. Cox proportional hazard models were used for univariable and multivariate analyses to determine survival-related factors. A logistic regression model was used to establish a joint diagnosis, and the feasibility of the combined diagnosis to evaluate the prognosis of MA-ILD was explored.Results: Among 47 anti-MDA5-positive patients with MA-ILD, EAR was an independent predictor of survival. When separated into high and low subgroups, high MLR (> 0.604) and EAR (> 1.458) were predictive of survival (p < 0.05). High MLR, high EAR, and age combined with lactate dehydrogenase were the highest (0.886) in predicting the prognosis of MA-ILD, and were higher than the area under the curve diagnosed separately. In 57 anti-MDA5-negative patients with MA-ILD, NLR and high EAR (> 0.872) were independent predictors of survival (p < 0.05).Conclusion: MLR and EAR are associated with prognosis in anti-MDA5-positive patients. NLR and EAR are associated with prognosis in anti-MDA5-negative patients. Using NLR, MLR, and EAR, inflammatory conditions of MA-ILD can be predicted and possible outcomes estimated.

[COVID-19 pandemic: global epidemiological trends and China's subsequent preparedness and responses].

The outbreak of COVID-19 has spread quickly across 114 countries/territories/areas in six continents worldwide and has been announced as a pandemic by WHO. This study analyzed global COVID-19 epidemiological trends, examined impact of the pandemic on global health security, diplomacy, and social environment in China, and provided short- and long-term strategic policy recommendations for China's subsequent preparedness and responses.

[Arab-Islamic medicine in the 12th century from the Persian ancient book Chahar Maghaleh].

The book named Chahar Maghaleh(Four Discourses) is written by Nizami Aruzi Samarqandi, a Persian writer in twelfth century. The book records 12 stories that can be regarded as medical records. Through the analysis of the 12 cases, we can get a lot of Arabia-Islamic medical information before and after 12th century, including basic concepts, medical academic origin, diagnostic methods, treatment methods and other content.That reflects the medieval Arabia-Persian society medical level.Compared with traditional Chinese medicine, ancient Arabia-Persian society had distinct features in medicine, food therapy, external therapy, psychotherapy and other fields; in the treatment of ideas and methods of diagnosis, they share some similarity with traditional Chinese medicine.

Equation Derivation of the Probability Distribution of IBS Score among Full Sibling Pairs.

ABSTRACT: Objective To derive the general equation of the probability distribution of identity by state （IBS） score among biological full sibling pairs by calculating STR allele frequency. Methods Based on the Mendelian genetics law and the hypothesis that parents of biological full siblings （FS） were unrelated individuals, the IBS score and corresponding probability of different genotype combinations in the offspring when unrelated individuals of different genotype combinations give birth to two offsprings were derived. Results Given fi （i=1, 2, …, m） as the frequency of the ith allele of a STR locus, the probability of sharing 2 alleles （p2FS）, 1 allele （p1FS） or 0 allele （p0FS） with biological full sibling pairs on the locus can be respectively expressed as follows： (see the text). The sum of p2FS, p1FS and p0FS must be 1. As for the multiple genotyping system that contained n STR loci, IBS scores between biological full sibling pairs conform to binomial distribution： IBS~B（2n, π1）. The population rate π1, can be given by the formula： (see the text). Conclusion The alternative hypothesis in biological full sibling testing is that two appraised individuals are biological full siblings. The probability of the corresponding alternative hypothesis of any STR locus combination or IBS score can be directly calculated by the equations presented in this study, and the calculation results are the basis for explanations of the evidence.

A rat osteoporosis model induced by ovariectomy and glucocorticoid.

Osteoporosis is characterized by reduced bone mineral density (BMD) and changes in bone morphometry, which increases the risk of fracture. However, the lack of proper models of significant osteoporosis limits our study of related medications and fracture mechanisms. The objective of this study was to determine whether a combination of ovariectomy (OVX) and glucocorticoid injection was appropriate for establishing an osteoporosis animal model. Female Sprague-Dawley rats were divided into sham, an OVX group, a glucocorticoid injection osteoporosis (GIO) group, and an OVX + GIO group. All animals were sacrificed in their 26th week and their spines and bilateral femurs were harvested and analyzed. Their bone quality elements, including BMD, trabecular bone architecture, and cortical bone thickness were analyzed via micro-CT, and mechanical strength of the spines was measured with a Universal testing machine, TO-101G. Femur neck and total femur mean BMD (g/cm2) in the OVX + GIO group (0.307, 0.439) was significantly lower than the sham group (0.518, 0.644) and the GIO group (0.485, 0.587). Femur neck cortical bone thickness (cm) in OVX + GIO group (0.369) were significantly less than those in the OVX group (0.421) or the GIO group (0.510). Furthermore, the OVX + GIO group had significantly lower mechanical strength than the other groups in the spine. In conclusion, OVX combined glucocorticoid injection could induce significant bone loss that had poorer bone quality and less mechanical strength than simple OVX or glucocorticoid injection had, without significantly increased mortality. Therefore, OVX + GIO might be an appropriate osteoporosis animal model.

[Genotyping of ABO Blood Group in Partial Population of Yunnan Province by SNaPshot Technology].

OBJECTIVES: To detect the genotype of ABO blood group by SNaPshot technology. METHODS: DNA were extracted from the peripheral blood samples with known blood groups （obtained by serology） of 107 unrelated individuals in Yunnan. Six SNP loci of the 261th, 297th, 681th, 703th, 802th, and 803th nucleotide positions were detected by SNaPshot Multiplex kit, and relevant genetics parameters were calculated. RESULTS: In 107 blood samples, the allele frequencies of types A, B, OA, and OG were 0.355 1, 0.168 2, 0.230 0 and 0.247 6, respectively, while that of types AG and cis AB were not detected. The genotyping results of ABO blood group were consistent with that of serologic testing. CONCLUSIONS: SNaPshot technology can be adapted for genotyping of ABO blood group.

[Analysis of clinical effect of McDonald cervical cerclage and the related risk factors].

OBJECTIVE: To investigate the clinical effect of McDonald cervical cerclage and the affecting factors. METHODS: Between January 2002 to December 2013 in Peking University First Hospital we performed McDonald cervical cerclage for 116 single pregnant women. They were defined as the successful group who deliveried the live babies after 28 weeks after the cerclage and the failure group who deliveried in the second trimester. According to the surgical indications they were divided into preventive cerclage group and therapeutic cerclage group. Then we analyzed the curative effect and the affecting factors in the groups. RESULTS: (1) In the 116 cases, 12 cases (10.3%) failed, and 104 cases (89.7%) succeeded. In the successful group, 37 cases (35.6%,37/104) deliveried pretermly and 67 cases (64.4%) deliveried termly. And there were 56 cases of vaginal delivery (53.8%), and 48 cases (46.2%) of cesarean section. (2) Among the 116 cases, 48 cases (41.4%) were included in prophylactic cerclage group, the gestational age was (16.3± 2.2) weeks, 68 (58.6%) cases were included in therapeutic group, the gestational age was (24.0±2.2) weeks. The operation time was (22±9) minutes in preventive group and (24±13) minutes in therapeutic group, there was no statistical difference between the two groups (P>0.05). Live-birth rate between preventive cerclage group and therapeutic cerclage group was no statistically significant difference (P>0.05). The term birth rate (72.9%, 35/48) in preventive group was higher than that in therapeutic group (47.1%, 32/68), the difference was statistically significant (P<0.01). Neonatal hospitalization rate was lower in preventive group (14.6%, 7/48) than therapeutic group (36.8%, 25/68) , the difference was statistically significant (P< 0.01). (3) In the failure group placental pathology was examed in 7 cases. The placental tissue showed a large number of neutrophils infiltrating in 6 cases (6/7). In the successful group, 27 pregnant women deliveried between 28 to 33(+6) weeks (26.0%,27/104), 10 pregnant women deliveried between 34 to 36(+6) weeks 10 cases (9.6%, 10/104), 67 cases deliveried after 37 weeks (64.4%, 67/104). A lot of factors including maternal age, the previous cervix operation history, perioperative application of progesterone, operation time and preoperative invasive procedure were compared between the successful group and the failure group. Only maternal age and preoperative invasive proedcure were statistically significant (P<0.05) and the others had no statistical significance (P>0.05). (4) There were 68 cases in the therapeutic group, 7 cases failed, and 61 cases succeeded; the preoperative cervical os in failure group [(21 ± 20) mm] was wider than that in successful group [(14±5) mm], the difference was statistically significant (P<0.05); and preoperative vaginal ultrasound measurement of cervical canal length were (18 ± 8) mm versus (19 ± 10) mm, there was no statistically significant difference (P>0.05). CONCLUSIONS: The McDonald cervical cerclage for cervical incompetence is a simple, safe and high successful rate of intervention measures. The term labor rate of prophylactic cervical cerclage was higher than that of the therapeutic cerclage. Older maternal age and preoperative invasive procedure may be the risk factors for cerclage. The infection may play an important factor leading to the failure of McDonald cervical cerclage.

Expression and significance of the imprinted gene PEG10 in placenta of patients with preeclampsia.

The aim of this study was to investigate the expression and significance of the imprinted gene PEG10 (paternally expressed gene 10) in preeclampsia placental tissue. Quantitative real-time reverse transcriptase polymerase chain reaction and immunohistochemistry to evaluate mRNA and protein expression and distribution of PEG10 in placental tissues obtained from 22 preeclampsia patients (8 patients with mild preeclampsia, 14 cases of severe preeclampsia). At the same time, 22 cases of normal pregnant women served as controls. PEG10 expression was determined in the placental tissue of the two different groups. In the normal pregnancy group, the average expression level of PEG10 was 0.5832 ± 0.045, while in the preeclampsia group, this level was 0.1943 ± 0.035. Statistical analysis showed that the two groups differed significantly (P < 0.05). The downregulated expression of the imprinted gene PEG10 may be an important reason for the occurrence of preeclampsia.

Long-term survival of cardiac allografts induced by cyclophosphamide combined with CTLA4Ig-gene transfer mediated by adenoviral vector.

There is a need to achieve donor-specific tolerance in clinical organ transplantation, where potential benefits remain overshadowed by chronic rejection and the side-effects of long-term immunosuppressive therapy. It is known that the mature immune system in mice can be reprogrammed to accept a foreign graft as if it was "self". The AdCTLA4Ig-mediated gene transfer (SC) + cyclophosphamide (CP) treatment alone prolongs allograft survival but does not induce tolerance. However, in our study, the AdCTLA4Ig-mediated gene transfer combined with SC + CP treatment yielded significantly prolonged mean survival times (149.7 +/- 18.0 days), while those in the untreated or AdLacZ treated mice were rejected in normal fashion (5.3 +/- 0.5 and 5.2 +/- 0.4 days, respectively), and survival in the AdCTLA4Ig or SC + CP treated groups were 45.7 +/- 9.6 or 50.2 +/- 5.3 days, respectively. In conclusion, a protocol of AdCTLA4Ig + SC + CP improved the survival of DA-->LEW cardiac allografts.

CTLA4-Fas ligand gene transfer mediated by adenovirus induce long-time survival of murine cardiac allografts.

BACKGROUND: Fas ligand gene transfer to induce peripheral allograft tolerance in animal models has shown controversial results. The immunosuppression effects mediated by engineered FasL depend on whether alloreactive T cells are selectively deleted. In the present study, we tested the feasibility of a strategy to induce long-time survival by fusing CTLA4-FasL gene transfer in vivo. METHODS: Cardiac allografts from DA(RT-1(a)) rats were transplanted heterotopically into the abdomens of LEW(RT-1(1)) rats. Plaque units (5x10(9)) of either AdCTLA4-FasL, AdCTLA4Ig, or AdEGFP were administered via the portal vein immediately after cardiac transplantation. The frequencies of helper T lymphocyte precursors (HTLp) and cytotoxic T lymphocyte precursors (CTLp) were determined by a combined single limiting dilution assay on days 5 and 20 after transplantation. RESULTS: Cardiac allograft survival was significantly prolonged by either AdCTLA4-FasL or AdCTLA4Ig treatment(mean survival times [MST] of 71.0 +/- 3.7 and 45.7 +/- 2.4, respectively, n = 6) compared with untreated hosts or animals treated with AdEGFP(MST of 5.7 +/- 0.5 and 5.2 +/- 0.4, respectively, n = 6). In addition, treatment with AdCTLA4-FasL led to significantly prolonged allograft survival compared with AdCTLA4Ig treatment. Furthermore, the frequencies of HTLp and CTLp on day 20 among rats treated with AdCTLA4-FasL was lower than those on day 5, whereas frequencies of HTLp and CTLp on day 20 were similar with those on day 5 in the other groups. CONCLUSION: These results suggest that administration of an adenovirus encoding fusion CTLA4-FasL gene to rat recipients effectively decreased the size of alloreactive T cells and induced long-term survival of cardiac allografts.

Blockade of both CD28/B7 and OX40/OX40L co-stimulatory signal pathways prolongs the survival of islet xenografts.

CTLA4Ig, a recombinant fusion protein composed of the extracellular domain of human CTLA4 and the constant region of human IgG1, inhibits the interaction of CD28/B7 pathway by binding the B7 molecule. OX40Ig, a recombinant fusion protein composed of the extracellular domain of human OX40 and the constant region of human IgG1, abrogates the interaction of OX40/OX40L pathway by binding the OX40L on APCs. So blockade of CD28/B7 or OX40/OX40L co-stimulatory pathways alone in mice with CTLA4Ig or OX40Ig can result in finitely prolonging the survival of islet grafts (43.2 +/- 4.81 and 67.7 +/- 7.74 days, respectively). In this study, a novel replication-defective adenovirus containing both of the CTLA4Ig and OX40Ig genes, AdCTLA4Ig-IRES-OX40Ig, was constructed by homologous recombination and injected into the streptozocin-rendered diabetic BalB/c mouse recipients (H-2d) through the tail vein, at the same day, the freshly isolated islets from Lewis rats (RT-1) were transplanted under the left kidney capsule of the recipients. The results showed that the mean survival time of the islet xenografts in the AdCTLA4Ig-IRES-OX40Ig-treated diabetic mice was significantly prolonged (100.3 +/- 14.94 days), while those in the untreated or AdEGFP-treated mice were rejected in normal fashion (6.7 +/- 0.94 and 7.0 +/- 1.0 days, respectively). In conclusion, utilizing AdCTLA4Ig-IRES-OX40Ig in vivo which can simultaneously express CTLA4Ig and OX40Ig proteins can improve the survival of Lewis-->BalB/c islet xenografts.

Low-dose donor bone marrow cells and splenocytes plus adenovirus encoding for CTLA4Ig gene promote stable mixed chimerism and long-term survival of rat cardiac allografts.

Co-stimulatory blockade combined with donor bone marrow transfusion engenders stable mixed chimerism and robust tolerance to various organ and cell transplants. However, repeated administration of costly agents to block the co-stimulatory pathway and the high doses of donor bone marrow cells (BMCs) used in most protocols are impeding clinical development of this strategy. To circumvent these shortcomings, we developed a plan in which repeated administration of costly agents was replaced by a single injection of adenovirus containing the gene of interest, and the high dose of donor BMCs replaced by a mixture of low-dose donor BMCs and splenocytes (SPLCs). Cardiac allografts from DA(RT-1(a)) rats were transplanted heterotopically into the abdomens of LEW(RT-1(1)) rats. A cocktail of adenovirus containing CTLA4Ig gene (AdCTLA4Ig), donor BMCs (100 x 10(6)), and SPLCs (50 x 10(6)) was administered to recipients via the portal vein immediately after grafting (n = 6). Treatment with regimens, including AdCTLA4Ig only, AdCTLA4Ig plus donor BMCs, and AdCTLA4Ig plus donor SPLCs, significantly prolonged cardiac allograft survival in recipient rats, while animals that received no treatment or treatment with control adenovirus (AdLacZ) promptly rejected their allografts. Nevertheless, LEW recipients treated with AdCTLA4Ig and the mixture of a low dose of donor BMCs and SPLCs developed stable mixed chimerism, rendering them long-term survivors of cardiac allografts that also accepted skin grafts from the donor but not the third-party strain. We conclude that blockade of CD28-B7 pathway with AdCTLA4Ig plus a mixture of low doses of donor BMCs and SPLCs is a feasible strategy to induce long-term mixed chimerism with a potential application for clinical development.

Bicistronic adenovirus-mediated gene transfer of CTLA4Ig gene and CD40Ig gene result in indefinite survival of islet xenograft.

Blockade of CD40-CD154 costimulatory pathway in mice and primates with anti-CD154 monoclonal antibodies results in prolonged survival of vascularized organs and islet grafts. CD40Ig, a recombinant fusion protein comprised of the extracellular domain of human CD40 molecule in frame fused with the site-mutated human IgG1 Fc region, abrogated the cognate interaction of CD40-CD154 pathway by binding the CD154 molecule. In this study, replication-defective adenovirus containing the CD40Ig gene was prepared by homologous recombination and used to infect freshly isolated islets from LEW rats (RT-1(1)) in vitro using a titered dose. The islet transfectants (500 per recipient) were transplanted under the left kidney capsule of streptozocin-rendered diabetic C57BL/6 mouse recipient (H-2(b)). The mean survival time of AdCD40Ig-transfected islet grafts was significantly prolonged, while mock-infected grafts and AdEGFP-transfected grafts were rejected in normal fashion. Additionally, dose-dependent prolongation of islet graft survival was observed in mice receiving AdCD40Ig-transfected grafts. In conclusion, local production of Cd40Ig via adenoviral-mediated gene transfer induced dose-dependent prolongation of LEW --> Balb-c islet xenografts.

Effects of acute hypotension on neuronal activity in the medial vestibular nuclei of rats.

The role of peripheral vestibular receptors in acute hypotension was investigated in anesthetized rats. In animals with intact labyrinths, acute hypotension induced by either i.v. infusion of sodium nitroprusside or hemorrhage produced excitation of electrical activity in two-thirds of type I neurons and inhibition in two-thirds of type II neurons recorded in the medial vestibular nuclei. In unilaterally labyrinthectomized animals, two-thirds of type I neurons ipsilateral to the lesion showed an inhibitory response, and two-thirds of contralateral type I neurons showed an excitatory response after the induction of acute hypotension. The response patterns of type II neurons were opposite to those of type I neurons. These results suggest that blood flow changes are detected by peripheral vestibular receptors, and that this might suggest a mechanism for control of blood pressure.

Purification and properties of major alpha-D-mannosidase in the luminal fluid of porcine epididymis.

A lysosomal type alpha-D-mannosidase was successfully purified by DEAE-Sephacel, Red-Amicon and Superdex 200 column chromatographies from porcine cauda epididymal fluid. The purified enzyme consisted of 63 and 51 kDa subunits at equimolar amounts. It cleaved alpha1-2 linked mannosyl residues and less but significantly cleaved alpha1-3 and alpha1-6 linked mannosyl residues in the high-mannose oligosaccharides. The optimal pH to hydrolyze oligosaccharide was in the acidic pH range (pH 3.5 approximately 4.0). Total alpha-D-mannosidase activities in the porcine epididymal fluid increased from proximal to distal caput epididymis, which maintained to cauda epididymis. At least two kinds of alpha-D-mannosidase (lysosomal type enzyme and 135 kDa alpha-D-mannosidase (MAN2B2)) were contained in the porcine epididymal fluid. The activity of the lysosomal type enzyme is much higher than MAN2B2 at the physiological pH. These results suggest that the lysosomal type alpha-D-mannosidase is the predominantly active enzyme in the luminal fluid of porcine epididymis and that it participates in the glycoprotein modification on the sperm surface during epididymal transit.

A porcine homolog of the major secretory protein of human epididymis, HE1, specifically binds cholesterol.

A porcine homolog of the major secretory protein of human epididymis, HE1, was for the first time purified from the porcine cauda epididymal fluid. The HE1 homolog was secreted into the epididymal fluid as a 19-kDa glycoprotein, whose sugar moiety was gradually processed to form a 16-kDa protein during transit through the epididymis. The HE1 homolog mRNA was detected only in the caput and corpus epididymis among the porcine tissues examined. The purified HE1 homolog specifically bound cholesterol with high affinity (Kd=2. 3 microM). The binding stoichiometry was determined to be 0.94 mol/mol, suggesting that 1 mol of cholesterol binds to 1 mol of the protein. It was also found that the HE1 homolog is a major cholesterol-binding protein in the porcine epididymal fluid. The possibility that the HE1 homolog is involved in the regulation of the lipid composition of the sperm membranes during the maturation in epididymis is discussed.

Functional analysis of peripheral blood B cells in patients with X-linked agammaglobulinemia.

X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disease caused by mutations of Bruton tyrosine kinase (Btk); Btk plays an essential role in the development of mature B cells. However, small numbers of B cells ("leaky B cells") are present in the peripheral blood of most XLA patients. In this study, we analyzed the function of these leaky B cells obtained from XLA patients. Enough numbers of B cells were available for analysis from five of nine XLA patients originally screened. Sequence analysis revealed missense mutations of Btk in four of the five XLA patients. No mutation was found in the coding region of Btk in one patient. Western blotting and/or flow cytometric analysis failed to detect Btk protein in all five patients. B cells isolated from peripheral blood of these XLA patients were CD5-, CD20+, CD19+, and CD21-. If stimulated with anti-CD40 and IL-4, XLA B cells proliferated normally and produced significant amounts of IgE. Anti-CD40 stimulation of XLA B cells resulted in normal expression of CD23. In addition, three of the five XLA patients studied were immunized with bacteriophage phiX174 and produced low but detectable levels of antiphage-specific Ab. Similarly, X-linked immunodeficiency mice, which carry a missense mutation in Btk, produced substantial amounts of antiphage Ab. These results indicate that CD40 signaling is intact in B cells lacking demonstrable Btk, and that leaky B cells in XLA patients can proliferate, undergo isotype switching, and differentiate into specific Ab-producing cells.

Direct evidence for the secretion of lactoferrin and its binding to sperm in the porcine epididymis.

Lactoferrin has been for the first time purified from the porcine cauda epididymal fluid as a 70 kDa protein. Both Western and Northern blot analyses show that lactoferrin is synthesized in the regions from the distal caput to the cauda epididymis and secreted into the luminal fluid. Lactoferrin is first secreted as a 75 kDa glycoprotein and its carbohydrate moieties are gradually digested to form 70 kDa protein in the cauda epididymis. Lactoferrin has already bound to the surface of the epididymal sperm because the anti-lactoferrin antiserum induces the mature sperm tail-to-tail agglutination. These results strongly suggest new physiological functions of lactoferrin on the sperm maturation in the epididymis.

Stage-specific expression of a mouse homologue of the porcine 135kDa alpha-D-mannosidase (MAN2B2) in type A spermatogonia.

The cDNA encoding a mouse homologue of porcine epididymis-specific 135kDa alpha-D-mannosidase (MAN2B2, D28521) was cloned from the mouse testis cDNA library. It was found that 1018 amino acids were coded in its open reading frame, and 62% of the amino acid sequence was identical to that of porcine MAN2B2. In the adult mouse, testis contained higher amounts of mRNA encoding the MAN2B2 homologue than the epididymis, though porcine MAN2B2 was mainly expressed in the narrow region between the caput and corpus epididymis. mRNA of the mouse MAN2B2 homologue was localized exclusively in spermatogonia in the testis. It was specifically expressed in type A spermatogonia at stages IX-XI of spermatogenesis and was detected there until the cell developed into type B spermatogonia. We conclude that the expression of the MAN2B2 homologue can serve as a good marker for the late stages of type A spermatogonia and may have an important role to play in the early step of spermatogenesis in mice.