Effects of androgens and estrogens on the vasopressin and oxytocin innervation of the adult rat brain

Recently we reported that castration of rats eliminates vasopressin immunoreactivity in the lateral septum and other areas that appear to receive vasopressin innervation from the bed nucleus of the stria terminalis. Testosterone treatment counteracts this effect of castration. In the present study, we investigated whether this action of testosterone depends on its androgenic or estrogenic metabolites by treating long-term castrated rats with estradiol (E) and/or 5 alpha-dihydrotestosterone (DHT) or testosterone. The brains were then processed for immunocytochemistry or radioimmunoassay. DHT did not increase vasopressin staining in the lateral septum, although it fully restored the size of the seminal vesicles. E did restore the original fiber density, but individual fibers stained more weakly than in sham-operated males. Only treatment with both E and DHT fully restored the vasopressin innervation. This pattern was also reflected in the radioimmunoassay data. The vasopressin content of the lateral septum decreased about 90% after castration but was fully restored by either testosterone or E + DHT treatment. E alone, however, was only half as effective as E + DHT. The treatments had no effect on the oxytocin content of the septum, or on the vasopressin or oxytocin content of the dorsal vagal complex. The results suggest that E mediates most of the effects of testosterone on the vasopressin innervation of the lateral septum. DHT enhances the response to E but has little effect on its own.     

Nutritionists in industry can play a key role in helping to achieve Health of the Nation targets for nutrition

Nutritionists working in food manufacturing and retailing are potentially in a more powerful position than any other professional group to contribute towards achieving the national targets for nutrition and the reduction of nutrition-related diseases, set out in The Health of the Nation (DoH, 1992) and in Scotland's Health, A Challenge to Us All (Scottish Office, 1993). The present paper sets out the details of this argument. First, a review is given of the functions and types of activities carried out by nutritionists in industry. Then a number of key practical ways in which nutritionists, through their activities and functions, can help towards achieving national targets for nutrition and nutrition-related diseases are described. Finally, suggestions are made about the knowledge, skills, and personal attributes needed by nutritionists who intend making successful careers in industry and who wish, at the same time, to contribute towards improving the health of the nation.     

Rotative agitation RIA: A high sensitivity technique for hepatitis B surface antigen (HBsAg) determinations

With the objective of finding a simpler and more sensitive method than conventional radioimmunoassay testing to detect HBsAg, we have modified the sample volume and first incubation procedure of the Ausria IIA method. There was an up to 9-fold increase in sensitivity without loss of specificity, in different assays, when the first incubation was carried out with a serum sample of 1 ml that was rotatively agitated for 22 h at room temperature. Additionally, 71 samples from which conventional testing had isolated hepatitis B core antibodies were tested with the modified rotative agitation technique and 9 of these specimens (12.67%) were positive for HBsAg. Routine employment of the rotative agitation radioimmunoassay technique to screen HBsAg by blood banks, to detect potential infectious donations that escape conventional testing, could be an effective as well as low-cost procedure to prevent post-transfusion hepatitis B.     

Micro-Raman line broadening in synthetic carbonated hydroxyapatite

Using a Raman microspectrometer, we have recorded Raman spectra of synthetically produced hydroxyapatite samples with varying carbonate contents. The apatites were produced from aqueous solutions at about 40 degrees C. From line-broadening values of the symmetric phosphate stretch, it was concluded that the carbonate substitution in these lattices has a maximum of 4.5 wt %. Both phosphate and hydroxyl ions seem to be involved in the carbonate substitution process.     

Treatment time analysis for extensive amalgam restorations

The treatment times for the fabrication of Extensive Amalgam Restorations (EAR) as recorded in a longitudinal clinical trial at the Dental School in Nijmegen were analyzed. 269 EAR's with different retention methods were made on molars by three operators. A mean total treatment time of 60 min was found. The factor operator had a significant influence on all treatment phases resulting in a 26% difference in total treatment time between operators. Also significant influences were found in some treatment phases for the factor retention, side location of the tooth and extension of the restoration. The results of this study with regard to treatment times must be considered from the perspective of the quality of the care provided.     

Pedal and distal lower leg bypasses with a distal arteriovenous fistula

In forty patients 41 feet were revascularised by means of distal tibial (the distal 10 cm of the lower leg) (17) or pedal bypasses (24). Angiographically the preoperative state was best defined as a lower leg block (LLB); All three arteries showing occlusions at several levels, leaving only isolated functioning arterial segments in the distal leg or foot with relatively good femoral and popliteal arteries. As might be expected this condition was mainly found in diabetics (75%). Only feet with severe rest pain (4) or rest pain with gangrene (37) were operated upon. To improve the distal outflow a side-to-side arteriovenous fistula (AVF) was added to the distal anastomosis. With a mean follow-up of 21 months (1-40 months) the limb salvage rate was 79% and the patency rate 67%. Special problems were experienced with cellulitis of the foot, causing the loss of three feet despite an open bypass and sufficient revascularisation. Furthermore, occlusion of the bypass after healing of the lesion did not necessarily mean a recurrence of gangrene. As this series shows, even in angiographically apparently hopeless cases, a bypass to the foot can prevent an otherwise unavoidable amputation.     

Maturation of a primitive neuroectodermal brain tumor? A case study with some remarks on the classification and nomenclature of 'primitive' CNS tumors

A brain tumor in a 4-year-old child is described. The neoplasm was partly cystic and showed an a-typical multi-differentiated aspect. Microscopically the neoplasm had a clear-cut 'malignant' morphology. This tumor represents possibly a partly maturated primitive neuroectodermal brain tumor. The term PNET is briefly discussed in relation to the clinical implications.     

A graphite transmission ionization chamber

A pancake-type transmission chamber made of high-purity graphite and open to the atmosphere has been designed and constructed at the Secondary Standard Dosimetry Laboratory (SSDL-Rio de Janeiro). Tests performed on the chamber following the International Electrotechnical Commission recommendations indicate that its performance characteristics are comparable to those expected from a secondary standard ionization chamber.