The South African journal of medical sciences最新文献

Free carboxylic acids were converted into mixed anhydrides suitable for the acylation of nucleophilic drugs in a one-step procedure. By preparing more than one acyl derivative and comparing the retention times of the derivatives with those of authentic drug samples with reference to suitable internal standards, the positive identification of unknown drugs was possible. The method is suitable for use in conjunction with the microphase extraction of drugs.

The possible use of the swimbladder of carp as auxiliary respiratory organ when the animals are exposed to air has been studied. After exposure to air, blood pH and pO2 and mean swimbladder O2 concentration decrease and blood pCO2 increases in normal animals. Exposure to air after ligation of the pneumatic ducts results in increases in blood pH and pCO2 and decreases in blood pO2 and swimbladder carbon dioxide concentration. Possible reasons for these observations are discussed.

d-Propoxyphene and d-norpropoxyphene were determined in rat plasms, rat brain homogenates and human plasma by means of GLC utilizing extracts obtained by micro-phase extraction of the drugs. Paracetamol was determined in the same samples by GLC separation of the O-butyrate derivative using caffeine as internal standard. The problems associated with the GLC determination of d-propoxyphene and d-norpropoxyphene in biological material are discussed and attention is drawn to the particular advantages of the micro-phase extraction procedure for the quantitative determination of these drugs.

It has been demonstrated that low concentrations of basic lipophilic drugs in biological fluids may be extracted and concentrated 10(4)-10(6) times by a series of extraction procedures in which the ratio of the extracting solvent to that of the solution to be extracted is of the order of 1:100 (microphase extraction procedure). Typically, basic drugs (atropine, aminopentamide, hyoscine, chloroquine, pyrimethamine) were extracted and concentrated sufficiently for direct GC analysis from 24-hour urine samples by a procedure involving three simple consecutive extraction steps. Using this procedure, it was demonstrated that after administration of aminopentamide (300 micrograms) to patients in the form of anti-diarrhoeal tablets, measurable quantities of the free, unchanged drug can be demonstrated in 24-hour urine samples. The main advantages of the method are simplicity, rapidity and sensitivity due to the low background interference in the GC separations. The principle involved can be extended to the analysis of acidic drugs with suitable solubility properties.

Forty-five human malignant tumour specimens were cultivated in vitro in an attempt to determine the necessary conditions for tumour cell maintenance and to establish permanently-growing cell lines. Continuously-growing cultures were derived from five tumours, including carcinomas of the oesophagus and colon, a hepatoma, a mesothelioma and a retroperitoneal sarcoma. The carcinoma of the oesophagus and the hepatoma, which have adapted fully to in vitro conditions, can be regarded as established cell lines.

Laboratory tests were made with Aedes (Neomelaniconion) unidentatus McIntosh and Aedes (Aedimorphus) dentatus (Theobald) collected from the Highveld region of the Transvaal, South Africa, to determine their ability of transmit West Nile and Sindbis viruses. Viraemic hamsters or a viraemic chick were exposed to the mosquitoes as infective meals. Infection of mosquitoes was determined by testing mosquitoes individually for the presence of virus 10-26 days later. Transmission of virus, attempted between the 10-20th days by exposing hamsters to groups of mosquitoes, was not achieved. With West Nile virus, the high concentrations of virus required to infect each species led to the conclusion that neither is an important vector of this virus. With Sindbis virus and A. unidentatus the 10 per cent infection threshold was less than 2,6 logs of virus, while with A. dentatus it was about 3,5 logs. This suggests that both species, but more particularly A. unidentatus, could be vectors of this virus.

The nuclear configuration and topography of the epithalamus, subthalamus and hypothalamus of the vervet monkey (Cercopithecus aethiops) are described and compared with those of other primates, particularly the macaque monkey. The epithalamus does not show any striking structural differences, except some architectonic differentiation in the lateral habenular nucleus. The subthalamus is a phylogenetically stable structure throughout the primate scale; it does not show any significant changes, except that it extends less rostrally and that the nuclei entopeduncularis and peripeduncularis are much smaller and less well defined in the vervet monkey than those in the diencephalon of lower primates. The nucleus subthalamicus and the fields of Forel, though small in size, are comparatively well developed; the zona incerta appears to be differentiated cytoarchitectonically into two parts. The hypothalamus is divided morphologically into four regions--the preoptic, supraoptic, infundibular and mamillary regions. Although the hypothalamus of the vervet monkey is topographically identifiable with those of other primates, there are cyto- and myeloarchitectonic differences to be found in certain hypothalamic nuclei and areas. The preoptic region is small and poorly delimited from the parolfactory region antierorly and the supraoptic region posteriorly. The nucleus paraventricularis is large and well differentiated into secretory and non-secretory portions; the nucleus supraopticus does not show cellular separation into dorsolateral and ventromedial parts as clearly as they are in other primates. The nucleus dorsomedialis is not as well defined as the nucleus ventromedialis like it is in other primates. The nucleus tuberalis lateralis is comparably small, and is not split into several cellular groups as it is in higher primates. The posterior hypothalamic area is morphologically the best definable of the hypothalamic areas. The mamillary region is developmentally advanced, and very well differentiated into medial, lateral and intercalated nuclei.

The sample, although small, represents the total number of children attending the Johannesburg Chinese Kuo Ting Primary and High School in 1972 to 1974. The frequency of the non-taster gene was found to be 0,167 in the combined male and female sample. The gene for red-green colour blindness is present in the Johannesburg Chinese population but at low frequnecy, 0,012. The mean age at menarche was found to be 12,8+/-1,23 years and is younger than the mean ages recorded for a number of Caucasoid populations. It is suggested that this difference in mean age reflects possibly varying genetic rather than varying socio-economic factors.