Serotonin metabolism in directly developing frog embryos during paternal care

Central serotonin (5-HT) metabolism during embryogenesis and a 3-day post-hatching period was analyzed using high performance liquid chromatography in the directly developing frog, Eleutherodactylus coqui. This anuran bypasses the free-swimming larval stage and embryos hatch as miniature frogs in the adult phenotype. During embryogenesis and for a short time immediately after hatching, male E. coqui provide paternal care by brooding and guarding eggs/embryos to prevent desiccation and predation. Serotonin and its catabolite, 5-HIAA, were measured from whole brain during embryogenesis and at 3 days post-hatch to identify critical periods in 5-HT development and to determine the relationship between 5-HT and life history events such as hatching and frog dispersal from the nest site. Serotonergic activity was highest during the early-mid embryonic stages as indicated by the ratio of 5-HIAA/5-HT, a general indicator of turnover and metabolism. There were significant increases in tissue concentrations of 5-HT during the latest or terminal embryonic stage, just prior to hatching, and also at 3 days post-hatch, shortly before neonates disperse into the rainforest. These two increases probably represent different functional requirements during development. The first may occur as a result of the surge of development in the 5-HT system during late embryogenesis that occurs in E. coqui and the second may be from the increase demand in sensory and motor neural development required before dispersal from the nest site.     

A "crackleware" oesophagus

This case report describes a 70 year old woman with excessive diffuse keratinisation of the oral cavity and oesophagus harbouring a squamous cell carcinoma. This excessive diffuse keratinisation of normally non-keratinised squamous epithelium could not be identified in normally non-keratinised epithelia in other parts of the body (the vagina), arguing against a genetic basis for this disorder. The term "crackleware" oesophagus was used to describe this entity, which has not been described previously in the English literature.     

Morphogenetic and functional activity of type II cells in early fetal rhesus monkey lungs

To evaluate further the role of type II alveolar epithelial cells in primate lung development, lungs of fetal (46 to 155 days gestational age [DGA]), postnatal, and adult rhesus monkeys were investigated with antibodies against surfactant protein A (SP-A), Alcian blue (AB) staining, and periodic acid-Schiff (PAS) staining with/without alpha-amylase pre-treatment. In adult and postnatal lungs, type II cells (cuboid shape; large, roundish nucleus) displayed a unique cytoplasmic staining for SP-A. In prenatal lungs, a low-columnar to cuboid type of cell with a large, roundish nucleus was first detectable by 62 DGA. It was the only cell type to line the distalmost tubules or buds of the prospective respiratory tract. It exhibited (initially partial) cytoplasmic staining for SP-A. AB and PAS stainings showed the presence of acid glycoconjugates and large apical and/or basal glycogen fields. After 95 DGA, the lining of the distal respiratory tract additionally displayed flatter cells with immunoreactivity for SP-A and non-reactive zones. Columnar epithelium (pseudostratified or simple) never stained for SP-A. We conclude that morphologically identifiable type II cells first appear in fetal rhesus monkey lungs by 62 DGA (pseudoglandular period). The cells may already synthesize surfactant and extracellular matrix components. They generate type I cells, and thus the entire pulmonary acinus lining. These conclusions for the rhesus monkey fully agree with our earlier conclusions for another primate, the human, and for rodents. However, as presently shown, primates differ greatly from rodents with respect to the timing of type II cell differentiation (at 29–38% versus 73–75% of gestation or at 22–25% versus 48–49% of prenatal lung development). © 1992 Wiley-Liss, Inc.     

Apoptosis and apoptosis-associated parameters in relation to tamoxifen exposure in postmenopausal endometrium

Tamoxifen increases endometrial cell proliferation and the incidence of endometrial cancer in postmenopausal women. The purpose of this study was to evaluate apoptosis and apoptosis-related factors in endometrium in relation to tamoxifen exposure. We analyzed benign postmenopausal endometrium from breast cancer patients receiving tamoxifen (n = 35) and from controls (n = 24), and endometrial cancer tissue from tamoxifen-treated breast cancer patients (n = 15) and endometrial cancer from women without tamoxifen exposure (n = 51). Apoptosis was examined morphologically, and the percentage of apoptotic epithelial cells was defined as the apoptotic index. In the benign samples, the presence of apoptotic cells was also evaluated immunohistochemically by the expression of caspase-3 and the monoclonal antibody M30. The expression of Fas, FasL, and Bcl-2 was analyzed in all tissue samples. No differences were observed in the mean apoptotic index in benign endometrium in tamoxifen users (0.17%) versus controls (0.08%), or in tamoxifen-exposed (2.46%) versus nonexposed endometrial cancer (2.28%). However, the ratio of the apoptotic index with the previously reported proliferation index was lower in benign endometrium from tamoxifen users than in controls (0.02 +/- 0.026 vs. 0.05 +/- 0.03, Mann-Whitney U <0.005). In benign endometrium FasL was more frequently expressed in tamoxifen-users than in controls (chi(2) <0.05). We conclude that the apoptosis/proliferation ratio in benign endometrium from tamoxifen users is lower than in controls, indicating that the tamoxifen-induced higher proliferation is not compensated for by increased apoptosis. An imbalance between cell proliferation and apoptosis, and possibly suppression of the antitumor immune response by FasL overexpression in tamoxifen-exposed endometrium might play a role in the development of endometrial cancer in tamoxifen users.     

Comparative genotyping of Campylobacter jejuni by amplified fragment length polymorphism,multilocus sequence typing,and short repeat sequencing: strain diversity,host range,and recombination

Three molecular typing methods were used to study the relationships among 184 Campylobacter strains isolated from humans, cattle, and chickens. All strains were genotyped by amplified fragment length polymorphism (AFLP) analysis, multilocus sequence typing (MLST), and sequence analysis of a genomic region with short tandem repeats designated clustered regularly interspaced short palindromic repeats (CRISPRs). MLST and AFLP analysis yielded more than 100 different profiles and patterns, respectively. These multiple-locus typing methods resulted in similar genetic clustering, indicating that both are useful in disclosing genetic relationships between Campylobacter jejuni isolates. Group separation analysis of the AFLP analysis and MLST data revealed an unexpected association between cattle and human strains, suggesting a common source of infection. Analysis of the polymorphic CRISPR region carrying short repeats allowed about two-thirds of the typeable strains to be distinguished, similar to AFLP analysis and MLST. The three methods proved to be equally powerful in identifying strains from outbreaks of human campylobacteriosis. Analysis of the MLST data showed that intra- and interspecies recombination occurs frequently and that the role of recombination in sequence variation is 50 times greater than that of mutation. Examination of strains cultured from cecum swabs revealed that individual chickens harbored multiple Campylobacter strain types and that some genotypes were found in more than one chicken. We conclude that typing of Campylobacter strains is useful for identification of outbreaks but is probably not useful for source tracing and global epidemiology because of carriage of strains of multiple types and an extremely high diversity of strains in animals.     

Impaired hepatocyte survival and liver regeneration in Atm-deficient mice

Atm is a stress-induced DNA damage checkpoint protein kinase with multiple roles in cell-cycle progression. Recent evidence indicates that Atm also plays a role in stem cell maintenance and self-renewal. It is not known whether Atm has a role during tissue regeneration. Using liver regeneration as a model system, we examined the role of Atm in this process. Here, we show that the expression levels of Atm protein were gradually increased during liver regeneration and this was correlated with the onset of DNA replication. The induction of Stat3 and JNK signaling, which are essential processes in normal regeneration response, was attenuated during the early phases of liver regeneration in Atm-deficient mice. P53 was transiently phosphorylated at serine 23 during liver regeneration in an Atm-dependent manner. In addition, we found that cyclin A induction was delayed and p21 was over-expressed, both of these processes were correlated with reduced and delayed DNA replication in Atm(-/-) mice during liver regeneration. Finally, we show that increased apoptosis was observed in Atm(-/-) mice in response to partial hepatectomy, indicating that Atm is required for the survival of hepatocytes. Collectively, these data indicate that liver regeneration is impaired in Atm-deficient mice. Given that liver is the first line of defense against environmental toxins, the elucidation of the function of Atm and Atm-mediated signaling pathways in liver metabolism and in response to environmental toxins is of fundamental interest.     

Users and non-users of doctors — implications for self-care

Sixty patients who visited their general practitioner were matched with 60 patients registered with the same doctor, who were of the same sex and in the same ten-year age group, and who had not visited the doctor for at least one year, but had recently experienced symptoms similar to those presented by the attending patients.

Comparison of the 60 pairs revealed the following differences, all substantial although not all statistically significant. The patients who visited the doctor perceived themselves as less healthy, fewer had attempted self-treatment, more reported serious personal problems, and fewer reported obstacles to visiting the doctor.

Differences between the pairs were negligible for total number of current ailments, effectiveness of self-treatment, if used, optimism about the healing powers of doctors, and fear of troubling their doctor with trivia.

     

PC program for comparing tracking indices in several independent groups

A method for computing a measure of tracking based on Cohen's kappa statistic for one-sample longitudinal data sets was previously described and implemented. This paper shows how one may test the equality of several kappas, each computed from an independent longitudinal sample. Thus, it is possible to formally compare groups of individuals with regard to stability in growth (or adaptive) patterns. Relative assessments of predictability in growth outcomes in different populations can be made with this approach. Also, when a common value of kappa is not contradicted by the data, a method to estimate this value and obtain a confidence interval for it is shown. A menu-driven GAUSS program for carrying out the procedure is described and made available. The method and program are illustrated with three samples of Guatemalan children. © 1992 Wiley-Liss, Inc.