Hormonal regulation of sex differentiated parameters in liver nodules from rats treated in the resistant hepatocyte model

Sex differentiation of liver functions has been shown to be attenuated in preneoplastic rat liver nodules. The present study was performed to investigate whether nodules from male rats are to some extent withdrawn from the normal growth hormone (GH) regulation of these functions. Male and female Wistar rats were treated according to a modified resistant hepatocyte model (RH-model), with diethylnitrosamine initiation and promotion with intragastric administration of 2-acetylaminofluorene (2-AAF) combined with partial hepatectomy (PH). Eleven months post-initiation male rats were treated with either human (hGH) or bovine growth hormone (bGH) or ovine prolactin (oPRL) by continuous infusion for 1 week. The mRNA expression of a number of genes known to be sex differentiated in liver from adult control rats was compared in nodular and surrounding tissue from nodule-bearing male, female and hormone-treated male rats. The basal mRNA expression of the female-predominant cytochrome P4502C12 (CYP2C12) was increased and the male-predominant CYP2C11 was decreased in liver nodules from male rats compared with the surrounding liver. Expression of the prolactin receptor (PRL-r; female > male) and the steroid 5 alpha-reductase (female > male) genes was decreased in male nodules, whereas no difference was observed with respect to GH-receptor (GH-r; female > male) expression in nodules versus surrounding tissue. Early nodules obtained from males treated according to the original RH-model (dietary 2-AAF, 0.02%) and isolated 2 weeks after completion of the 2-AAF/PH treatment showed significantly lower GH-r mRNA levels than the total liver tissue. In hepatocellular carcinomas from hormonally unmanipulated males 11 months post-initiation the decrease in PRL-r expression was even more pronounced than in the nodules and a significant decrease in GH-r expression was seen. In female nodules the only significant difference with respect to the sex differentiated parameters was a lower 5 alpha-reductase expression than in the surrounding tissue. Continuous infusion of both hGH and bGH feminized the expression of all the sex differentiated genes in male tissues and eliminated the previously detected differences between nodules and surrounding tissue. oPRL also eliminated the differences between nodules and surrounding tissue in males and partly feminized the expression of both the 5 alpha-reductase and the PRL-r genes.(ABSTRACT TRUNCATED AT 400 WORDS)     

An evaluation of clinical laboratory services in sub-Saharan Africa. Ex africa semper aliquid novi?

Pathology services represent the rational, scientific basis of the practice of clinical care. It does not represent deus ex machina, an implausible solution to a complex plot, but rather the way in which clinical care can be audited, controlled, guided and kept appropriate to the funds and the skills available. Arguments are presented to support this statement as well as to analyse what is wrong with health care, from the point of view of laboratory medicine, in sub-Saharan Africa. In most African countries 'first world' technology has to be imported by economies barely able to sustain the basic requirements of human life. Badly needed foreign exchange is obtained by growing export crops at the cost of traditional lifestyle, disenfranchising communities, urbanisation, and even at the cost not being able to grow food. War, corruption, lack of accountability even in the Western sense of being able to go to the polls every so often, lack of empowerment, low literacy rate etc all debase the communities, with minimal exceptions, of Africa. Health care is under the same capricious rule as all other public services: investment in laboratories is poor and most have no access to a professional laboratory at all. More investment, not less; expansion of pathology services not restricting them, is needed throughout the continent.     

Endo-epsilon-(gamma-Glu)Lys-isopeptidolysis as a sign of highly-specific proteolysis

Catalytic activity of destabilase has been studied in hydrolyses of synthetic and natural substrates. High specificity of the enzyme is shown in hydrolysis of endo-epsilon-(gamma-Glu)Lys isopeptide bonds.     

Maxillary distraction osteogenesis in Pfeiffer's syndrome: urgent ocular protection by gradual midfacial skeletal advancement

Distraction osteogenesis is increasingly recognised as a potentially useful technique to achieve the co-ordinated augmentation of craniofacial skeletal and soft tissue. A case is presented where bilateral maxillary distraction was successfully used to advance the midface in the treatment of recurrent ocular dislocation, in a 10-month-old boy with Pfeiffer's syndrome.     

Radionuclides in the Kara sea bottom sediments

The contents and distribution of natural (214Pb, 214Bi, 228Ac, and 208Tl) and technogenic (90Sr, 137Cs, and 60Co) radionuclides in the Kara Sea bottom sediments was analyzed by using the materials collected by R/V "Pomor" (Murmansk Marine Biological Institute). In 1994, no high (critical) concentrations of technogenic radioisotopes were found in the sea sediments, while the spots (regions) of elevated 137Cs content found in 1984 were not confirmed in 1994. It was proposed that the main sources of entry of technogenic radionuclides in the sea sediments in the last years are the flow of the Ob'-Yenisei waters and container burials of radioactive waste in the sea, which appeared to have been markedly corroded. The latter is confirmed by detection in some places of 60Co, which was not previously found in the sediments.     

Volatile Losses from Sphene Glass-Ceramic and Borosilicate Glass Melts

Heating experiments have been performed with titanosilicate glass melts to investigate possible losses of volatile radionuclides during preparation. The melts are precursors to sphene glass-ceramics, the latter being candidate materials for immobilization of nuclear fuel recycle wastes. After the titanosilicate melts were heated for up to 24 h at 1300° and 1400°C, weight-loss measurements and X-ray fluorescence spectrometry analyses indicated that Cs, Mo, and, to a lesser extent, Na were the main contributors to the observed losses by volatilization. For comparison, similar experiments were performed with an AVM-type borosilicate glass at temperatures of 1150° and 1250°C, when the viscosities are approximately equal to those of the titanosilicate melts at 1300° and 1400°C, respectively. The losses from the borosilicate glass were predominantly due to Na, B, Cs, and Mo volatilization and were generally higher than the corresponding losses from the titanosilicate glass, typically by factors of ∼4. Possible speciation of the volatile components in these glasses is discussed.     

Finite element technique for the assessment of 3-1 and "super 1-3" connectivity piezoelectric composite transducers

This paper describes the use of finite element (FE) technique in the assessment of new types of multilayered piezoelectric composite structure using the PZFlex code. The background information leading to model configuration, including materials properties and boundary conditions, is discussed. This is coupled with an experimental program of model corroboration via a number of key stage prototypes to achieve a model-build-test methodology. Initially the 3-1 connectivity plate and multilayered piezoelectric composites are analyzed. Results from FE and experimental assessment indicate that the 3-1 plate devices offer no benefit over the conventional 1-3 connectivity arrangement. A simple, minimally diced, 3-1 connectivity multilayer device is analyzed and is shown to be suitable for the manufacture of wideband and efficient transducers operating in the 10-100 kHz frequency range for high power applications.