Estrogen and progesterone receptors can be maintained in normal human breast epithelial cells in primary culture and after transplantation into nude mice

The estrogen and progesterone receptor expression was determined in breast epithelial cells from reduction mammoplasty specimens. Only a subset of the luminal epithelial cell population was found to be positive for these receptors. When these cells were subsequently cultured in 3-dimensional collagen gel system (in vitro model) or transplanted into nude mice (in vivo model), the cells retained their ability to express both receptors in these experimental systems. The maintenance of primary normal human breast epithelial cells expressing the estrogen and progesterone receptors in experimental systems has not been reported previously.

Isolation of oncogenes from rat mammary tumors by a highly efficient retrovirus expression cloning system

A majority of mammary tumors induced with N-methyl-N-nitrosourea in rats contain G to A transitional mutation of c-Ha-ras at the 12th codon. Additional oncogene activation is known to be necessary for further tumor progression. To isolate novel oncogenes, we used an expression cloning system utilizing the pMX retroviral vector in combination with BOSC23 packaging cells. First, we elucidated the sensitivity of this system in the NIH 3T3 focus assay; foci were detectable even after 10(-6) dilution using v-Ha-ras, neuT, and beta-galactosidase constructs in pMX vector. This system is sensitive enough to detect low copy number cDNAs. We used the pMX/BOSC23 expression cloning system to clone novel oncogenes from rat mammary tumors harboring an activated c-Ha-ras and isolated several candidate oncogenes that caused transformation of NIH 3T3 cells and/or generated tumors when transplanted to nude mice.

Germ cell apoptosis in the testes of Sprague Dawley rats following testosterone withdrawal by ethane 1,2-dimethanesulfonate administration: relationship to Fas?

Germ cell apoptosis, which occurs normally during spermatogenesis, increases after testosterone withdrawal from the testis. The molecular mechanism by which this occurs remains uncertain. The Fas system has been implicated as a possible key regulator of apoptosis in various cells: binding of Fas ligand (FasL), a type II transmembrane protein, to Fas, a type I transmembrane receptor protein, triggers apoptosis in cells expressing Fas. Recently, Fas has been localized to germ cells, and FasL to Sertoli cells, within the rat testis. We hypothesized that Fas protein content would rise in response to reduced levels of testosterone as part of a suicide pathway that would result in germ cell apoptosis. To test this hypothesis, ethane 1,2-dimethanesulfonate (EDS), a Leydig cell toxicant, was used to kill Leydig cells and thus reduce intratesticular testosterone levels in Sprague Dawley rats. Apoptosis was examined in situ and biochemically, and Fas protein content in the testis was monitored by Western blot analysis. We show that EDS injection results in the following sequence of events: apoptotic death of Leydig cells by a mechanism that does not involve Fas; reduced testosterone; increased testicular Fas content; and germ cell apoptosis. These results suggest that Fas may play a role in the apoptotic death of germ cells that results from reduced intratesticular testosterone levels, and that testosterone may play a role in germ cell survival via its suppression of Fas.

Clonal diversity among recently emerged strains of Vibrio parahaemolyticus O3:K6 associated with pandemic spread

The genomes of the O3:K6 strains of Vibrio parahaemolyticus which abruptly emerged in Calcutta, India, in February 1996 and which demonstrated an unusual potential to spread and an enhanced propensity to cause infections were examined by different molecular techniques to determine clonality. No restriction fragment length polymorphism (RFLP) in the gene encoding the thermostable direct hemolysin was observed among the O3:K6 isolates of V. parahaemolyticus. Clonal diversity among the O3:K6 strains became evident by examining the RFLPs of the rrn operons and by the use of pulsed-field gel electrophoresis. Five ribotypes were distinguished among the O3:K6 strains examined, with ribotype R4 constituting the major type. Strains of O3:K6 isolated between June and August 1996 showed different pulsotypes compared to the pulsotypes of strains isolated before and after this period, indicating genetic reassortment among these strains, but those isolated between August 1996 and March 1998 showed identical or nearly similar pulsotypes. It is clear that there is a certain degree of genomic reassortment among the O3:K6 clones but that these strains are predominantly one clone.

Protective effects of pregnancy and lactation against N-methyl-N-nitrosourea-induced mammary carcinomas in female Lewis rats

The role of parity before and after N-methyl-N-nitrosourea (MNU) treatment in protection against mammary carcinogenesis was investigated. The effect of lactation on reduction in the incidence of mammary carcinoma was also examined. Parous rats were compared with respective age-matched virgins (AMVs). Pregnancy and lactation prior to MNU exposure significantly reduced both the incidence of mammary carcinoma (22 versus 72%) and the average number of mammary carcinomas per rat (0.22 versus 0.86) and significantly prolonged the latency of the carcinomas (247 versus 215 days). Pregnancy and lactation following MNU exposure also significantly reduced both the incidence of mammary carcinoma (25 versus 94%) and the average number of mammary carcinomas per rat (0.25 versus 1.50) and significantly prolonged the latency (240 versus 155 days). Lactation showed an additive effect on the reduction in mammary cancer. Pregnancy suppressed the number of estrogen receptor (ER)- and progesterone receptor (PgR)-positive cells and lowered the cell proliferation rate in the non-tumoral mammary glands. Since the majority (>76%) of the mammary carcinomas was hormone dependent in both the parous and AMV rats, pregnancy and lactation appear to decrease the ER- and/or PgR-positive cells presumed to be the progenitors of hormone-dependent carcinomas and they lowered the cell turnover necessary for tumor promotion in parous rats, resulting in a lower mammary carcinoma yield.

Bovine ephemeral fever: a review

Bovine ephemeral fever is a viral disease of cattle and buffaloes besides subclinical involvement of a variety of ruminant species. The subtropical and temperate regions of Africa, Asia and Australia have experienced the major epidemic of the bovine ephemeral fever but the occurrence in the tropics can not be overlooked. Although the substantial role played by the vectors viz., mosquitoes and culicoides in bovine ephemeral fever perpetuation and dissemination, other vector involvement if any should be extensively studied. The clinical severity of the disease is not apparent and the mortality is low. However, high morbidity, enormous economic losses in terms of significant reduction in production, disruption of national and international trade and finally a variety of complications resulting from the disease have drawn appreciable attention from the researchers around the world to resolve the unsolved questions in this area. In this review, detailed informations of all the aspects of the disease has been provided in a simple, lucid and easily understandable manner.

Induction of mammary carcinomas by N-methyl-N-nitrosourea in ovariectomized rats treated with epidermal growth factor

The importance of epidermal growth factor (EGF) in both normal and malignant mammary gland development are presented in these studies. Initial findings demonstrated that in the absence of ovarian hormones, EGF had a significant proliferative effect on mammary epithelial cells. To determine whether mammary epithelial cells grown with EGF, in the absence of ovarian hormones, could be transformed by N-methyl-N-nitrosourea (MNU), female ovariectomized Lewis rats were implanted with pellets containing EGF for 1 week and then treated with MNU for initiation. Two days after MNU treatment, ovaries were implanted and EGF pellets were removed from all ovariectomized groups in order to promote carcinogenesis. The mammary carcinoma incidence of the EGF-stimulated group (90%) was not significantly different from the intact group (100%). The mammary cancer morphology of EGF-treated carcinomas was either ductal carcinoma or cribriform adenocarcinoma, whereas intact animals developed mainly papillary and occasional cribriform carcinomas. Fifty-eight percent of the carcinomas from the EGF group were ovarian hormone-independent compared with 10% of carcinomas from the intact group. These results demonstrate that EGF-induced proliferation during initiation with MNU was sufficient to induce the transformation of mammary carcinomas in the absence of ovarian hormones. The hormonal dependency of these EGF-induced carcinomas were different compared with MNU-initiated mammary carcinomas in intact rats.

Hormonal prevention of breast cancer: mimicking the protective effect of pregnancy

Full term pregnancy early in life is the most effective natural protection against breast cancer in women. Rats treated with chemical carcinogen are similarly protected by a previous pregnancy from mammary carcinogenesis. Proliferation and differentiation of the mammary gland does not explain this phenomenon, as shown by the relative ineffectiveness of perphenazine, a potent mitogenic and differentiating agent. Here, we show that short term treatment of nulliparous rats with pregnancy levels of estradiol 17beta and progesterone has high efficacy in protecting them from chemical carcinogen induced mammary cancers. Because the mammary gland is exposed to the highest physiological concentrations of estradiol and progesterone during full term pregnancy, it is these elevated levels of hormones that likely induce protection from mammary cancer. Thus, it appears possible to mimic the protective effects of pregnancy against breast cancer in nulliparous rats by short term specific hormonal intervention.

Resurgent Vibrio cholerae O139: rearrangement of cholera toxin genetic elements and amplification of rrn operon

The unprecedented genesis of a novel non-O1 Vibrio cholerae strain belonging to serogroup O139, which caused an epidemic in late 1992 in the Indian subcontinent, and its subsequent displacement by El Tor O1 vibrios after 18 months initiated a renewed investigation of the aspects of the organism that are related to pathogenesis. The reappearance of V. cholerae O139 with altered antibiotic sensitivity compared to O139 Bengal (O139B) in late 1996 has complicated the epidemiological scenario of V. cholerae and has necessitated an examination of possible rearrangements in the genome underlying such rapid changes in the phenotypic traits. With a view to investigating whether the phenotypic changes that have occurred are associated with alteration in the genome, the genome of the resurgent V. cholerae O139 (O139R) strains were examined. Pulsed-field gel electrophoresis analysis of NotI- and SfiI-digested genomic DNA of O139R isolates showed restriction fragment length polymorphism including in the cholera toxin (CTX) genetic element locus and with O139B isolates. Analyses of the organization of the CTX genetic elements in O139R strains showed that in contrast to two copies of the elements connected by two direct-repeat sequences (RS) in most of the genomes of O139B isolates, the genomes of all O139R strains examined, except strain AS192, have three such elements connected by a single RS. While the RS present in the upstream of the CTX genetic elements in the genome of O139R is of O139B origin, the RS connecting the cores of the elements has several new restriction sites and has lost the BglII site which is supposed to be conserved in all O1 strains and O139B. The endonuclease I-CeuI, which has sites only in the rrn operons in the genomes of all organisms examined so far, has 10 sites in the genomes of O139R strains, compared to 9 in the genomes of O139B strains. The recent isolates of V. cholerae O139 have thus gained one rrn operon. This variation in the number of rrn operons within a serogroup has not been reported for any other organism. The results presented in this report suggest that like the pathogenic El Tor O1 strains, the genomes of O139 strains are undergoing rapid alterations.

Influence of cumulus cells and sperm concentration on cleavage rate and subsequent embryonic development of buffalo (Bubalus bubalis) oocytes matured and fertilized in vitro

The objective of the present study was to investigate the effects of sperm concentration and presence or absence of cumulus cells on fertilization, cleavage rate and subsequent embryonic development upto the blastocyst stage in buffalo. Cumulus-oocyte-complexes (COCs) obtained from slaughterhouse ovaries were matured in vitro in TCM-199 + 10% FBS + 5 micrograms/mL FSH-P for 24 h. After maturation the COCs were either used as such (cumulus-intact) or freed from attached cumulus cells by repeated pipetting (cumulus-free). Frozen-thawed buffalo spermatozoa were treated with 10 micrograms/mL heparin and 2.5 mM caffeine for sperm capacitation. Oocytes were fertilized in vitro with 1 to 2, 4 to 5 or 9 to 10 million sperm/mL and the cleavage rate was recorded 42 to 44 h post insemination. The cleaved embryos were co-cultured with buffalo oviductal epithelial cells for 10 d post insemination, and the uncleaved oocytes were fixed and stained with aceto-orcein for determination of the penetration rate. The cleavage rate and the proportion of cleaved embryos that developed to morula and blastocyst stages were significantly higher (P < 0.05) whereas the proportion of degenerated oocytes and those that became arrested at the 2 to 16-cell stage were significantly lower (P < 0.05) with cumulus-intact than with cumulus-free oocytes at the 3 sperm concentrations. Increasing the sperm concentration increased the cleavage rate significantly (P < 0.05) from 1 to 2 million through 9 to 10 million sperm/mL but had no effect on the proportion of cleaved embryos that developed to morula and blastocyst stages. In conclusion, the results of the present study suggest that cumulus cells have a positive influence on fertilization, cleavage and subsequent embryonic development. Increase in sperm concentration increases cleavage rate without affecting subsequent embryonic development.

Changes in the parous rat mammary gland environment are involved in parity-associated protection against mammary carcinogenesis

Parity in rats results in protection from methylnitrosourea (MNU)-induced mammary cancer. Our goal was to determine if systemic alterations in the mammary gland environment after a full-term pregnancy rendered the parous rat an inadequate host for promotion of initiated mammary epithelial cells to become cancerous. Lewis rat MNU-treated mammary epithelial cells were transplanted into uniparous (UP), age-matched virgin (AMV) (both 130-150 d), or young virgin (YV) (50-60 d) syngeneic hosts to examine if differences in the systemic environments of the three hosts had an effect on hyperplasia and cancer formation. More transplants in YV and AMV hosts contained hyperplasias and adenocarcinomas as compared to transplants in UP hosts. In addition, UP host transplants had significantly fewer numbers of hyperplastic lesions than transplants from the virgin hosts. The evidence presented here shows that the uniparous host environment is less supportive than that of the virgin host for hyperplasia and cancer development.

Defective retrovirus insertion activates c-Ha-ras protooncogene in an MNU-induced rat mammary carcinoma

Endogenous retrovirus sequences are present in the genome of a wide variety of animal species. The activation of the proto-oncogenes of the ras family, particularly c-Ha-ras, by either point mutation or overexpression, has been shown to be associated with a vast number, of different cancers. here we report that the insertion of a defective retrovirus in the -1 intron of rat c-Ha-ras is responsible for the activation of the gene by over 10-fold overexpression in an MNU-induced rat mammary cancer. A portion of the 3' end of the retroviral sequence is expressed as a part of the c-Ha-ras transcript in the carcinoma tissue, indicating the direct involvement of this element in the transcription of the c-Ha-ras gene. The c-Ha-ras structural gene transcribed by the promoter of the defective retroviral element can neoplastically transform the NIH 3T3 cell line upon transfection.

Adeno-associated virus vector mediated transduction of primary normal human breast epithelial cells

Cultured human breast epithelial cells from reduction mammoplasty specimens were transduced using an adeno-associated virus vector encoding the marker gene E. coli -galactosidase. Subconfluent, growing, breast epithelial cells were more easily transduced than confluent, quiescent, cells. Transduction of non-dividing confluent cells could be greatly increased by ultraviolet light-induced DNA damage or by prior exposure to the DNA synthesis inhibitor hydroxyurea. The effects of ultraviolet light and hydroxyurea on transduction were additive when these agents were applied together.

Portal hypertensive gastropathy and gastric varices before esophageal variceal sclerotherapy and after obliteration

OBJECTIVES

To evaluate the frequency and clinical importance of portal hypertensive gastropathy (PHG) and gastric varices (GV) before endoscopic sclerotherapy (EST) and after esophageal variceal obliteration.

METHODS

Patients with portal hypertension (PHT) with variceal bleed were prospectively evaluated for PHG and GV before EST with intravariceal injection of absolute alcohol and after esophageal variceal obliteration. Gastric varices and PHG were characterized and graded according to previously established criteria. Patients were followed up for 12-48 (mean 37) months after variceal obliteration.

RESULTS

Of 70 patients with PHT 26 had PHG before (severe in two) [18/37 in cirrhosis, 6/20 in non-cirrhotic portal fibrosis (NCPF), and 2/13 in extrahepatic portal vein obstruction (EHPVO)] and 50 had PHG after variceal obliteration (severe in 22) (27/37 in cirrhosis, p = 0.03 before versus after esophageal variceal obliteration; 16/20 in NCPF, p < 0.01; and 7/13 in EHPVO, p = ns). Type I GV (continuation of esophageal varix into the stomach) was found in 25/70 before and 5/70 after esophageal variceal obliteration (p < 0.001); in contrast, other types of GV were seen in 14/70 before and 29/70 after (p < 0.01). Overt bleeding from GV and PHG during follow-up after variceal obliteration occurred in 6 and 4 patients, respectively.

CONCLUSIONS

Esophageal variceal obliteration by EST increases the frequency of PHG and GV (except type I GV which get obliterated); both PHG and GV have potential to cause rebleeding.

Evaluation of immunocapture ELISA for diagnosis of goat pox

An immunocapture enzyme-linked immunosorbent assay (IC-ELISA) for the detection of goat poxvirus (GPV) antigen in skin biopsy samples obtained from healthy and experimentally infected goats as well as from goats from field was evaluated. The assay was 80-100% specific and 70-86% sensitive, and was compared with a commonly used diagnostic test, namely, the counter immunoelectrophoresis (CIE) test in the efficacy for goat pox. Although IC-ELISA was marginally more sensitive than the CIE test, the diagnosis of goat pox could be successfully done provided both the tests were combined in screening scab suspensions. The IC-ELISA could also diagnose sheep poxvirus (SPV) infection.

Synergistic effect of MNU and DMBA in mammary carcinogenesis and H-ras activation in female Sprague-Dawley rats

The combined application of N-methyl-N-nitrosourea (MNU) and 7,12-dimethylbenz[alpha]anthracene (DMBA) was compared with the administration of each carcinogen alone as to the effectiveness of the induction of mammary carcinomas and the influence of H-ras oncogene activation in female Sprague-Dawley rats. At 50 days of age, group 1 received 30 mg/kg MNU intraperitoneally (i.p.), group 2 received 30 mg/kg DMBA i.p., group 3 received 60 mg/kg MNU i.p., group 4 received 60 mg/ kg DMBA i.p., group 5 received 30 mg/kg MNU followed by 30 mg/kg DMBA i.p., group 6 received 30 mg/kg MNU i.p. and then 30 mg/kg DMBA intravenously (i.v.) and group 7 remained untreated. Animals were killed when the largest mammary tumor reached 1-2 cm in diameter or were necropsied when they were 30 weeks of age. MNU i.p. produced no deaths (groups 1 and 3), however, the i.p. administration of DMBA induced death due to peritonitis (groups 2, 4 and 5), whereas the i.v. administration of DMBA suppressed the death (group 6). All of the tumors produced by MNU were adenocarcinomas of mammary origin. In contrast, DMBA produced tumors of other than mammary origin. The combined treatment with DMBA and MNU increased the mammary carcinogenic effect; it significantly increased the mean number of mammary cancers per rat. With either carcinogen alone and in combination, the mammary carcinomas produced identical adenocarcinoma histology. Of the mammary carcinomas induced by the combined application of MNU and DMBA (group 6), all 11 tumors from five rats showed the GGA to GAA transitional mutation in H-ras codon 12 (38%) and all 18 tumors from the other 10 rats remained as wild-type. An H-ras point mutation at codon 61 was not detected.

Rearrangements in the genomes of Vibrio cholerae strains belonging to different serovars and biovars

The intron-encoded enzyme I-CeuI provides an excellent tool for rapidly examining the organization of genomes of related species of bacteria. Vibrio cholerae strains belonging to serovars O1 and O139 have 9 I-ceuI sites in their genomes, and V. cholerae strains belonging to serovars non-O1 and non-O139 have 10 I-ceuI sites in their genomes. This information can be used as a criterion to differentiate O1 strains from non-O1 and non-O139 strains. To our knowledge, intraspecies variation in the number of rrn operons has not been reported in any other organism. Our data revealed extensive restriction fragment length polymorphism based on a comparison of the I-ceuI digestion profiles of strains belonging to different serovars and biovars. From the analysis of partial digestion products, I-CeuI macrorestriction maps of several classical, El Tor, and O139 strains were constructed. While the linkage maps are conserved within biovars, linkage maps vary substantially between biovars.

Mapping QTLs for submergence tolerance in rice by AFLP analysis and selective genotyping

By combining the amplified fragment length polymorphism (AFLP) technique with selective genotyping, we constructed a linkage map for rice and assigned each linkage group to a corresponding chromosome. The AFLP map, consisting of 202 AFLP markers, was generated from 74 recombinant inbred lines (RIL) which were selected from both extremes of the population (250 lines) with respect to the response to complete submergence. Map length was 1756 cM, with an average interval size of 8.5 cM. To assign linkage groups to chromosomes, we used 50 previously mapped AFLP markers as anchor markers distributed over the 12 chromosomes. Other AFLP markers were then assigned to specific chromosomes based on their linkage to anchor markers. This AFLP map is equivalent to the RFLP/AFLP map constructed previously as the anchors were in the same order in both maps. Furthermore, tests with two restriction fragment length polymorphism (RFLP) markers and two sequence-tagged site (STS) markers showed that they mapped in the expected positions. Using this AFLP map, a major gene for submergence tolerance was localized on chromosome 9. Quantitative trait loci (QTL) associated with submergence tolerance were detected on chromosomes 6, 7, 11, and 12. We conclude that the combination of AFLP mapping and selective genotyping provides a much faster and easier approach to QTL identification than the use of RFLP markers.

A study of psychiatric morbidity of the elderly population of a rural community in west bengal

A door to door field-survey was conducted in two villages by a team of psychiatrists with the aim of assessing the mental morbidity of the population. The present communication is restricted to the mental morbidity of the elderly population aged 60 years and above. The total sample comprised 183 persons (male 85, female 98). Majority of the families (44.2%) belonged to class IV according to Pareek and Trivedi's scale. Sixty one percent of the elderly population was mentally ill. Women had a higher rate of morbidity than men (77.6% and 42.4% repetitively). The overwhelming majority of the affected persons were depressives. Rate of dementia was low.

Biochemical characterization of FMDV A10 and A22 subtypes by PAGE and IEF

Both polyacrylamide gel electrophoresis (PAGE) and iso-electric focusing (IEF) have been standardized using the sucrose density gradient purified 146S particles of FMD virus subtypes A10 and A22. Differences in the molecular weights of structural proteins (VP1, VP2 and VP3 of two subtypes (A10 and A22) of FMDV have been revealed in PAGE but no appreciable differences in the pI of VP1, VP2 and VP3 is found in IEF.

Polymorphism, distribution, and segregation of AFLP markers in a doubled haploid rice population

We exploited the newly developed amplified fragment length polymorphism (AFLP) technique to study the polymorphism, distribution and inheritance of AFLP markers with a doubled haploid rice population derived from 'IR64'/'Azucena'. Using only 20 pairs of primer combinations, we detected 945 AFLP bands of which 208 were polymorphic. All 208 AFLP markers were mapped and distributed over all 12 chromosomes. When these were compared with RFLP markers already mapped in the population, we found the AFLP markers to be highly polymorphic in rice and to follow Mendelian segregation. As linkage map of rice can be generated rapidly with AFLP markers they will be very useful for marker-assisted backcrossing.