The effect of experimental induced hypocalcaemia on uterine activity in the sow during parturition and post-partum

Uterine activity was measured by monitoring intrauterine pressure changes using ballon-tipped catheters placed in the lumen. An infusion rate of Na(2)EDTA of 35 mg/Kg/h gave a chelation rate equivalent to the rate of calcium mobilisation, and when infused at a level greater than this, resulted in a reduction in plasma calcium concentrations and a concomitant reduction in uterine activity. In three of the four sows infused intrapartum, there was complete cessation of uterine activity; however, plasma calcium concentrations of less than 6 mg 100 ml resulted in a reduction in uterine activity at this stage of parturition. The uterus of the sow post-partum appeared to be more sensitive to the effects of hypocalcaemia with reduced uterine activity when plasma calcium concentrations fell below 8.2 mg 100 ml and complete cessation of activity between 6 and 7 mg 100 ml . Although there was evidence of a delay in the expulsion of piglets in the hypocalcaemic sows, there was no evidence of an increased number of stillborn piglets compared with the two control sows.     

Aspects of the biology of the euryhaline Asian cichlid,Etroplus suratensis

Synopsis Aspects of the biology of the euryhaline Asian cichlid Etroplus suratensis in a coastal lagoon of Sri Lanka were studied for a period of 15 months. Comparisons are made from the catches from the fishery of manmade, inland freshwater reservoirs. Changes in the stock structure in the sublittoral region of the lagoon indicate that recruitment takes place twice a year, during the high rainfall/low salinity periods. The feeding habits of E. suratensis were different in the two habitats. In the lagoon it fed mainly on molluscs and in the freshwater reservoirs on macrophytes. Feeding chronology based on diurnal surveys indicate that it feeds mainly during the daylight hours. The dentition of E. suratensis is adapted for both tearing and crushing (pharyngeal teeth). Distinct differences in the mean relative intestinal length between populations from the coastal lagoon and inland reservoirs were evident and these differences are correlated to their respective feeding habits. Diurnal changes in feeding activity are associated with changes in the stomach pH. The egg-diameter distribution of mature fish indicate that E. suratensis is a single spawner, that it sheds its mature eggs all at once. It is inferred that E. suratensis breeds twice a year but that an individual female is capable of spawning only once a year.     

A model of the spatial-temporal characteristics of the alpha rhythm

A linear spatially distributed model of a chain of neurons and interneurons was investigated in relation to the generation of propagated alpha rhythmic activity. It was assumed that the elements of the chain were interconnected by means of recurrent collaterals and inhibitory fibres in such a way that the connectivity functions were assumed to be homogeneous and their strength was an exponentially decreasing function of distance. It was found that such a neuronal chain shows propagation properties for frequencies in the alpha band. The results obtained with the model are in agreement with the phase velocities encountered experimentally. In this way, it was possible to estimate the length of the neural fibres responsible for the phenomenon of propagated activity. The estimates obtained are in good agreement with recent quantitative neuroanatomical data on the circuitry of the neocortex.     

Pelvic visceral arteries of rabbits (Oryctolagus cuniculus)]

40 pelvic preparations of rabbits (oryctolagus cuniculus) were bilaterally studied by dissection under the stereomicroscope and angiography. The arterial pattern of the pelvis, i.e. origin and branching of the umbilical, urogenital and internal pudendal arteries (visceral branches), is described. The main characteristics observed are as follows: (1) The umbilical artery is permeable in adults and gives origin to the cranial vesical artery and a caudal branch that irrigates the pelvic urogenital organs and, eventually, the rectum, with six patterns of branching in both sexes. (2) Usually, the urogenital artery is the continuation of the visceral branch of the internal iliac artery. In 1 animal, unilaterally, it arises from the median sacral artery. In 12 animals (6 bilaterally and 6 unilaterally) the urogenital artery is absent. When present, it forms two branches, a cranial and a caudal one, that irrigate of the urogenital organs in both sexes. (3) The internal pudendal artery is the direct continuation of the internal iliac artery and gives to rise to some visceral branches that irrigate the penis, bulbourethral gland and rectum (with six patterns of branching) in males, and the vagina, clitoris and rectum (with three patterns of branching) in females.     

Aliphatic hydrocarbons as biological markers in 250-million-year-old rock salt deposits near Kassel,West Germany

Organic matter sedimented within salt deposits from the Carboniferous Perm epoch has been investigated for hydrocarbons by gas-liquid-chromatography, mass spectrometry, and spectropolarimetry. Main constituents were made of aliphatic and olefinic hydrocarbons which retained a considerable part of their optical activity thus resisting complete racemization over 250 mio years.     

Active entry of bloodstream forms of Trypanosoma cruzi into macrophages.

The uptake of bloodstream forms of Trypanosoma cruzi, Y and CL stocks, by mouse peritoneal macrophages and their intracellular differentiation and multiplication has been compared in vitro. After 48 h the number of macrophages showing intracellular amastigote forms was higher when the Y stock was used. The number of parasitized cells increased with the time of contact between parasites and macrophages. Prior treatment of the parasites with anti-T. cruzi antibodies and/or complement increased the number of infected macrophages, but did not interfere with their subsequent differentiation within the macrophages. The number of parasitized cells was greater when macrophages were obtained from mice previously treated with lipopolysaccharide, peptone or thioglycollate. Uptake was not appreciably affected when macrophages were pre-treated with trypsin or anti-macrophage serum, or when the parasites and macrophages were incubated in the presence of cytochalasin B. In the same experimental conditions, epimastigotes of T. cruzi when not able to differentiate into amastigotes. Their uptake was potentiated by previous treatment with specific antibodies and/or complement and was blocked by cytochalasin B. These results confirm that epimastigotes derived from T. cruzi cultures are phagocytosed and suggest that bloodstream forms penetrate actively into macrophages.     

A family with a satellited Yq chromosome

Summary A large pedigree with a satellited Yq chromosome is described, Q, C, and NOR banding were performed. Family C proband suffers from a Klinefelter syndrome.     

Analytical strategies for therapeutic monitoring of drugs and metabolites in biological fluids : Plenary lecture

Therapeutic drug monitoring can involve quantitation in either microgram, nanogram or picogram concentrations present in a complex biological matrix (whole blood, urine or tissue).The chemical structure of a compound influences not only the analytical method best suited to its quantitation, but also its acid/base character (PK_a) and its extractability. The dose administered, the bioavailability of the dosage form, and the pharmacokinetic profile of the drug govern the circulating concentrations of either the parent drug and/or its metabolites present in vivo, and dictate the ultimate sensitivity and specificity required of the analytical method.The degree of sample preparation required is dependent on the analytical method used (gas—liquid chromatography, thin-layer chromatography, high-performance liquid chromatography) and on the tolerance of the specific type of detection system to contamination. Factors leading to compound losses during sample preparation (adsorption, stability) are critical at low concentrations and can adversely affect the reliability of an assay, therefore maximizing the overall recovery of the assay is essential not only for high sensitivity but also for good precision and accuracy. Therefore, the criteria to be used in sample preparation should aim to optimize all of the above factors in the overall development of a reliable and validated method for the compound suitable for use in clinical therapeutic monitoring.