Effects of acute hypoxia on incorporation of [1-14C]arachidonic acid into glycerolipids of rat brain

The effects of 1 min of acute hypoxic treatment (1% O₂ in N₂) on incorporation of [1-¹⁴C]arachidonic acid into brain lipids of 16-day-old rats were investigated at 3, 6, and 12 min after intracerebral injection of the labeled fatty acid. The hypoxic-hypoxia condition associated with convulsive seizures caused a decrease in the conversion of labeled arachidonate to its acyl-CoA as well as incorporation of the label into the brain phospholipids. Among the phospholipids, there was a specific decrease in the labeling of diacylglycerophosphoinositol (GPI), and this change was accompanied by an increase in labeling of the diacylglycerols. These results indicate that metabolism of the long-chain fatty acids and some glycero-lipids in brain are vulnerable to acute hypoxic treatment.     

Reproductive events and family history as risk factors for breast cancer in northern Alberta.

Reproductive events and family history as risk factors for breast cancer in northern Alberta were investigated with the use of data from a computerized population-based registry. Women aged 30 to 79 years attending diagnostic breast clinics at the Cross Cancer Institute from 1971 through 1975 constituted the two study groups; 1232 women had diagnosed breast cancer (malignant disease group) and 602 women were clinically free of all types of breast disease (control group). An increased relative risk of breast cancer was found in women with a family history of breast cancer, those who gave birth to their first term infant at age 30 years or older, those in whom more than 15 years elapsed between menarche and that birth, and those with a late natural menopause. There was a decreased risk, relative to nulliparity, in the postmenopausal women who first gave birth to a term infant 5 years or less after menarche. Artificial menopause (bilateral oophorectomy), parity and age at menarche had no apparent effect on the risk. The pattern of risk factors in northern Alberta differed from that reported for other geographic areas, including other provinces of Canada, thus emphasizing the need for local studies in the planning of screening programs.     

Epidémie de dysentérie bacillaire.

An outbreak of bacillary dysentery in 1978 affecting 928 persons, most of whom were living in the village of St-Jacques, PQ, is described. An epidemiologic study suggested the water supply as the source of the infection, and it was established that the water carried by the municipal aqueduct was contaminated by feces containing the causal agent, Shigella sonnei. This epidemic, the largest mentioned in he Canadian medical literature, demonstrates how contagious this infection is.     

Survival of patients treated for end-stage renal disease by dialysis and transplantation.

The results of treatment in 213 patients with end-stage renal disease who underwent hemodialysis, peritoneal dialysis or transplantation, or a combination, between 1962 and 1975 were analysed. Comparison by censored survival analysis showed significantly better (P less than 0.01) patient survival with the integrated therapy of dialysis and transplantation than with either form of dialysis alone. There was no significant difference in survival of males and females but survival at the extremes of age was poorer. Analysis of survival by major cause of renal failure indicated best survival in patients with congenital renal disease. Graft and patient survival rates at 1 year after the first transplantation were 42% and 69%. The major cause of death in this series was vascular disease but infection was responsible for 50% of deaths after transplantation. While integration of dialysis with transplantation produces best patient survival, this course is possible only when sufficient cadaver kidneys are available.     

Effect of food-deprivation on rat pancreatic islet cells

Somatostatin, insulin and glucagon concentrations in rat pancreas were measured following various intervals of food-deprivation. Tissue concentrations, as measured by radioimmunoassay, were correlated with A-, B-, and D-cell number and size using a scanning integrating image analyzer (Quantimet 720). Alterations in total islet hormone content were not correlated to changes in size or distribution of cells. This implies that changes in tissue content reflect changes in turnover of peptides rather than changes in cell size or number.     

Lithium Effects on Inositol Phospholipids and Inositol Phosphates: Evaluation of an In Vivo Model for Assessing Polyphosphoinositide Turnover in Brain

Administration of lithium chloride to rats injected intracerebrally with [3H]inositol led to time- and dose-dependent increases in levels of labeled inositol monophosphates in brain. Quantitative analysis of the inositol phosphates by ion chromatography revealed 37- and 20-fold increases in the mass of myo-inositol 1-phosphate and 4-phosphate, respectively, at 4 h intraperitoneal after injections of 6 mEq/kg of lithium chloride. Albeit to a much lesser extent, lithium administration also resulted in an increase in the level of myo-inositol, 1,4-bisphosphate in brain. The lithium-induced increase in content of labeled inositol monophosphates was marked by a concomitant decrease in content of labeled inositol, and after injections of high doses of lithium, e.g., 10 mEq/kg, this was followed by a general decrease in labeling of the inositol phospholipids. In general, animals injected with [3H]inositol but not lithium did not reveal obvious differences in labeling of inositol monophosphates on stimulation by mecamylamine or pilocarpine. However, when animals were injected with [3H]inositol and then lithium, there were large increases in the levels of labeled inositol monophosphates on administration of these compounds. Administration of atropine to the lithium-treated mice led to a partial reduction in the amount of labeled inositol monophosphates accumulated due to the administration of lithium alone. Furthermore, atropine was able to block the pilocarpine-induced increase in level of labeled inositol monophosphates. These results demonstrate the suitable use of the radiotracer technique together with lithium administration for assessing the effects of drugs and receptor agonists on the signaling system involving polyphosphoinositide turnover in brain.     

RELATIONSHIPS BETWEEN FLOODING TOLERANCE,LIFE HISTORY,AND SHORT-TERM COMPETITIVE PERFORMANCE IN THREE SPECIES OF POLYGONUM

The objective of this study was to compare the growth and short-term (single season) competitive performance of three species of Polygonum known to differ in flooding tolerance and life history. Polygonum amphibium is a perennial with low sexual reproductive effort and a relatively high degree of flooding tolerance, P. lapathifolium is an annual species with a high sexual reproductive effort and a low tolerance to flooding, and P. hydropiperoides is intermediate to the other two in terms of sexual reproductive effort and flooding tolerance. In order to determine the relative growth and competitive abilities of these species, mixtures and monocultures of plants were grown in pots and maintained under three flooding regimes: 1) flooded, 2) partially drained, and 3) well drained. Both P. hydropiperoides and P. amphibium grew best under flooded and partially drained conditions with reduced growth in the drained treatment. Polygonum lapathifolium, in contrast, grew as well in the drained treatment as in the more flooded treatments. Results from competition experiments were consistent in showing the relative competitive abilities to be P. lapathifolium > P. hydropiperoides > P. amphibium regardless of flooding regime. Thus, short-term competitive performance was found to trade off with flood tolerance rather than with sexual reproductive effort.     

Juvenile hormone esterases of Lepidoptera

Summary The juvenile hormone esterase (JHE) titer was measured during the last larval instar of 11 species of Lepidoptera (Pieris rapae, Junonia coenia, Danaus plexippus, Hemileuca nevadensis, Pectinophora gossypiella, Spodoptera exigua, Orgyia vetusta, Ephestia elutella, Galleria mellonella, Manduca sexta andEstigmene acrea). All species had a peak of JHE at or near the time of wandering. The peak activity at this time ranged from 0.8 to 388 nmoles JH III cleaved/min·ml. All species exceptJ. coenia had a second peak of JHE during the late prepupal stage. The height of the second peak ranged from 0.4 to 98.4 nmoles/min·ml. However, there was no apparent correlation between size of the first and second JHE activity peaks for the lepidopteran species examined. There was an apparent relationship between the height of the first and second JHE peaks and reports on titer of JH just prior to these peaks. These data support, with some qualifications, the extension of developmental information obtained on several well studied species to a variety of Lepidoptera.Abbreviations JH juvenile hormone - JHE juvenile hormone esierase - PTTH prothoracotropic hormone - R _o -10-3108 1-(4-ethylphenoxy)-6,7-epoxy-3-ethyl-7-methylnonane     

Evolutionary significance of the renal excretion of transferrin half-molecule fragments

It is generally thought that the duplicated structure of serum transferrin in vertebrates arose by gene duplication and fusion from a small ancestral protein. We have found that the isolated domains of transferrin are rapidly lost from the bloodstream via the kidneys. Therefore we suggest that the ancestral transferrin was not a serum protein or, alternatively, that it was not as small as the half-molecule.