Prostaglandin F2 alpha inhibits epidermal growth factor binding to cellular receptors on adipocyte precursors in primary culture

Prostaglandin F2 alpha (PGF2 alpha) and epidermal growth factor (EGF) are potent differentiation inhibitors of adipocyte precursors in primary culture. We show here that PGF2 alpha specifically inhibited EGF binding to adipocyte precursors in a dose dependent fashion. Scatchard analysis indicates that PGF2 alpha causes a 50% decrease in the number of available EGF cell surface receptors without change in receptor affinity. Comparison of EGF binding at different temperatures and on fixed cells indicates that PGF2 alpha increases internalization of EGF-receptor complexes in adipocyte precursors. Phorbol myristate acetate (PMA) also inhibited EGF binding in adipocyte precursors. PGF2 alpha effect was abolished in cells exposed to prolonged treatment with PMA indicating that PGF2 alpha effect on EGF binding is mediated by protein kinase C. These results would suggest that in adipocyte precursors PGF2 alpha may be the physiological mediator of phorbol ester effect on EGF receptor properties.     

Dual immunodetection and hybridisation in situ of opsin mRNA and rhodopsin protein in retinal sections

We describe a simple method for combining in situ hybridisation and immunohistochemistry on the same retinal section. The technique was developed using a radiolabelled cDNA probe for opsin and an antibody (ROS1F4) against rhodopsin. This method retains the antigenic sites if immunocytochemistry is performed prior to in situ hybridisation. Opsin mRNA was found in the photoreceptor inner segment with rhodopsin immunolocalised to the photoreceptor outer segments. The technique should be applicable to numerous situations including analysis of the sequence of events in the expression and synthesis of the various opsins during retinal development and degeneration.     

Prenatal determination of human platelet antigen type using DNA amplification following amniocentesis

OBJECTIVE: To assess the effectiveness of a newly developed individualised birthweight ratio (IBR), which corrects for physiological birthweight determinants, in identifying infants at risk from the complications of macrosomia. DESIGN: Prospective observational study. SETTING: Obstetric unit, Nottingham City Hospital. SUBJECTS: 2835 women delivered between December 1991 and July 1992 and the infants of 624 of these, selected by virtue of their birthweight for gestation and IBR centile positions. MAIN OUTCOME MEASURES: Skinfold thickness and ponderal index measurements, operative delivery, shoulder dystocia, fetal trauma, impaired glucose tolerance. RESULTS: Using an IBR above the 90th centile as a cut off results in 2.4% of infants being reclassified as normally grown and 3.1% are reclassified as large. The IBR does not result in the identification of any more infants with abnormal ponderal indices or skinfold thicknesses than birthweight for gestation. It does, however, identify more of the infants at risk of operative delivery, shoulder dystocia, fetal trauma and impaired glucose tolerance. CONCLUSION: The IBR significantly improves upon birthweight for gestation in identifying infants who suffer from the complications of relative macrosomia.     

Further observation of leucocyte migration through the endothelium of venules in the posterior latissimus dorsi muscle of the quail-chick spinal cord chimeras

The migration of leucocytes through the walls of venules was examined in detail in the posterior latissimus dorsi muscle of quail-chick spinal cord chimeras, in which flaccid paralysis of the wings was observed. Examinations were made from the 70th to 80th day after hatching. Muscle fibers were degenerated and intramuscular nerve bundles destroyed. Massive leucocytes (almost lymphocytes) were found around the venules, depending on the passage of wandering leucocytes through the endothelium. Lymphocytes penetrated and were encased in the cytoplasm of the venular endothelial cell, and did not pass through the interendothelial junction. These findings suggest that, in the venules of the atrophied chimeric muscle, wandering leucocytes in the blood may pass through the endothelial cell body and migrate into the inflamed extravascular space.     

Premature separation of centromere and aneuploidy: an indicator of high risk in unaffected individuals from familial breast cancer families?

OBJECTIVES: Injury is the leading cause of death in the male working population of Brazil. An important fraction of these deaths are work related. Very few cohort studies of steel workers, and none from developing countries, have reported on mortality from injuries. This paper analyses mortality from work and non-work related injuries among Brazilian steel workers. METHODS: Deaths during employment from 1 January 1977 to 30 November 1992 were analysed in a cohort of 21,816 male steel workers. Mortality rates specific for age and calendar year among the workers were compared with those of the male population of the state where the plant is located. Work related injuries were analysed by comparing the mortality rates for different subgroups of the cohort. RESULTS: The number of deaths (391) was less than half that expected based on death rates of the general population. Over 60% (242) of deaths were due to injuries. Mortality from most causes was substantially below that in the general population, but that from unintentional injury, was 50% above that of the general population. Standardised mortality ratios (SMRs) were highest for the youngest and the oldest employees and for labourers and clerical workers. Mortality from motor vehicle injury was twice that expected from population rates (SMR = 209, 95% confidence interval (95% CI) 176-244). There was a 67% fall in the age adjusted mortality from occupational injuries in the study period. CONCLUSION: The healthy worker effect in this cohort was greater than that commonly found in studies of occupational groups in developed countries, probably because of a greater socioeconomic gap between employed and unemployed populations in Brazil, and unequal distribution of health care resources. Mortality was especially high for motor vehicle injuries. The fall in mortality from occupational injuries during the study period was probably due to improvement in safety standards, increased automation, and better medical care. There is a need to investigate risk factors for unintentional injuries among steel workers, especially those due to motor vehicle injuries. Prevention of occupational and nonoccupational injuries should be a main priority in Brazil.     

Assay of acyclovir in human skin layers by high-performance liquid chromatography

This paper describes an assay procedure for acyclovir quantification in human skin after in vitro transdermal transport experiments. The procedure employs warm distilled water for acyclovir (ACV) extraction and high-performance liquid chromatography (HPLC) as analytical method. The procedure has good reproducibility, sensitivity and specificity, resulting in a reliable method for biopharmaceutical studies of ACV distribution in skin tissue. The chromatographic conditions set up, using distilled water as mobile phase, makes the analytical procedure simple and easy to perform.