Sublethal malathion induced changes in the ovary of an air-breathing fish,Heteropneustes fossilis: a histological study

This paper describes effects of a sublethal (1.2 mg 1^–1) organophosphate, malathion, on the ovary of an air breathing catfish, Heteropneustes fossilis. The study focuses on microscopic changes that occur on ovigerous lamellae, oocytes at different stages of development and the nucleus of the immature oocyte. Also, change in estrogen levels in blood serum is investigated. Clumping of cytoplasm appears after 24 h of exposure to malathion. Clumping intensified after 48 h. Degeneration in the follicular cells was also observed. After 72 h exposure the number of nucleoli increased, nuclear materials shrunk, oocytes became adhered. With 96 h of exposure, nuclear materials of all the oocytes shrunk to a smaller clump. The oocytes fused together, and follicular epithelium became loose and ruptured. A few atretic oocytes were visible. Radioimmunoassay of the estrogen level in blood serum after 72 h of exposure of malathion showed a reduction in the level. This study showed that the histopathological condition of the gonad is reflected in malfunctioning of the endocrine system and hormonal disbalance.     

The potential for rust infection to cause natural selection in apomictic Arabis holboellii (Brassicaceae)

Few studies have examined the potential for pathogens with complex life cycles to cause selection on their required alternate (=intermediate) hosts. Here we examine the effects of two fungal pathogens on an herbaceous mustard, Arabis holboellii. One pathogen species uses A. holboellii as a primary host, the other uses it as an alternate host. This plant-pathogen system is especially interesting because the host, A. holboellii, is apomictic; thus individuals reproduce exact copies of themselves. Despite this mode of reproduction, A. holboellii populations are surprisingly genetically diverse. Could frequency dependent selection by pathogens be maintaining clonal diversity? This study assesses the potential for selection by pathogens. In a controlled greehouse experiment we show that there is heritable variation in A. holboellii's resistance to the rust, Puccinia monoica, and that host fitness is severely reduced by P. monoica infection in both the greenhouse and under natural conditions. Field observations indicate that host clones are also differentially susceptible to the short-cycled rust, P. thlaspeos, and that host fitness is reduced by infection to this pathogen as well. Although the preconditions for pathogen-mediated selection are present, frequency-dependent selection by pathogens is unlikely to be important in structuring populations of Arabis holboellii because multiple host genotypes are susceptible to the same inoculum and the pathogen has a long generation time.     

Ibuprofen, a unique anti-inflammatory compound with antifungal activity against dermatophytes

Ibuprofen showed significant antifungal activity in vitro against dermatophytes at pH 5 (MIC: 5–40 μg ml^-1). In this respect it is comparatively more efficient than two well known and medically used antifungal compounds, benzoic and salicylic acids. This compound with anti-inflammatory activity which is not found in any other conventional antifungal organic acids, may have clinical prospects.     

Reversal of sexual impotence in male patients with chronic obstructive pulmonary disease and hypoxemia with long term oxygen therapy

Erectile impotence is commonly encountered in male patients with respiratory failure and hypoxia. In this study, 42% of the patients experienced reversal of sexual impotence during long term oxygen therapy (LTOT). We examine the association between sexual impotence, gonadal axis hormones, hypoxia, and oxygen therapy. Nineteen sexually impotent male patients eligible for LTOT (pO₂ < 7.3 kPa during stable disease) and with sexual impotence received oxygen therapy for 1 month (n = 12) or 24 h (n = 7). pO₂, LH, FSH, testosterone, and SHBG (sex hormone binding globulin) were monitored. Five of 12 patients receiving oxygen for 1 month regained sexual potency. The responders showed a significant increase in arterial pO₂ and serum testosterone, and a decline in SHBG compared to non-responders. None of the patients receiving oxygen for 24 h experienced reversal of sexual impotence, despite a significant increase in pO₂. In these patients, serum testosterone did not increase significantly. Reversal of sexual impotence may be achieved in some patients with respiratory failure. The oxygen therapy must, however be administered for an adequate length of time.     

Fatty Acyl-CoA Inhibits 1-Alkyl-sn-Glycero-3-Phosphate Acetyltransferase in Microsomes of Immature Rabbit Cerebral Cortex: Control of the First Committed Step in the De Novo Pathway of Platelet-Activating Factor Synthesis

Abstract: Microsomal fractions of cerebral cortices of 15-day-old rabbits were used to study the 1-alkyl- sn -glycero-3-phosphate (AGP) acetyltransferase that generates 1-alkyl-2-acetyl- sn -glycero-3-phosphate in the de novo path of platelet-activating factor synthesis. The AGP acetyltransferase activity was inhibited by small concentrations of medium-long chain fatty acyl-CoA thioesters. In contrast, the AGP acyltransferase used oleoyl-CoA as substrate and was not inhibited by the presence of acetyl-CoA in high molar excess. The inhibition of AGP acetyltransferase was seen at concentrations of oleoyl-CoA as low as 0.5 µ M using 12.5 µ M AGP and 200 µ M acetyl-CoA. The inhibition by oleoyl-CoA was noncompetitive for the acetyl-CoA substrate. However, there was evidence that the oleoyl-CoA was competing with AGP in the acetyltransferase reaction, as the inhibition was lessened by increasing the AGP substrate concentration. Several acyl-CoA thioesters were effective as inhibitors of the AGP acetyltransferase, including oleoyl-, palmitoyl-, lauroyl-, and octanoyl-CoA. Propionyl- and butyryl-CoA were less effective as inhibitors, and propionyl-CoA was found to be a competitive inhibitor for acetyl-CoA. We have noted earlier that MgATP is an effective inhibitor of the AGP acetyltransferase and here we show that the inhibition by oleoyl-CoA can be increased by the presence of 0.1 m M MgATP. In brain ischemia, a decline in ATP levels would likely lead to a corresponding fall in acyl-CoA concentrations, thereby relieving the inhibition of AGP acetyltransferase and permitting the flow of AGP into the de novo pathway of platelet-activating factor synthesis.     

Adenosine effects upon insulin action on lipolysis and glucose transport in human adipocytes

The dose response effect of a new adenosine analogue, GR 79236 (N-[1S trans-2-hydroxycyclopentyl] adenosine) upon insulin sensitivity was examined in human adipocytes. The influence of adenosine upon insulin sensitivity for suppression of lipolysis and stimulation of glucose transport was examined. Removal of adenosine by use of adenosine deaminase stimulated lipolysis to the same extent as did 10^–9 M noradrenaline. GR79236 brought about dose dependent inhibition of lipolysis with half-maximal effect at 11.3±7.8×10^–9 M. When lipolysis was stimulated by noradrenaline alone the subsequent inhibition of lipolysis brought about by GR79236 was significantly greater than that of insulin. To examine adenosine effects on the insulin signalling pathway separately from those on lipolysis, the insulin sensitivity of glucose transport was examined. Removal of adenosine brought about a small but significant increase in the concentration of insulin required for half-maximal stimulation of glucose transport. Adenosine agonists offer promise as new agents for the modulation of metabolism in diabetes and other states of insulin resistance.     

Long-Term Drug Treatment of Obesity in a Private Practice Setting

ATKINSON, RICHARD L, ROY C BLANK, DONALD SCHUMACHER, NIKHIL V DHURANDHAR, DOUGLAS L RITCH. Long-term drug treatment of obesity in a private practice setting. This study evaluated the long-term efficacy and safety of the combination of phentermine and fenfluramine for the treatment of obesity in a private practice setting. A total of 1388 consecutive, qualified patients presenting to a private general internal medicine practice in Charlotte, NC, were enrolled with eligibility criteria including: age 18 years to 60 years, 20% over “desirable” bodyweight or body mass index <27, no serious medical or psychiatric disease, and no contraindications to drug therapy. Patients were instructed in diet, exercise, and behavior modification techniques and received phentermine (15 mg/day to 30 mg/day) and fenfluramine (20 mg/day to 60 mg/day) continuously for over 3 years. Average duration of treatment was 15. 9 months, and average weight loss at the last visit was 11. 6 kg, or 11. 7% of initial bodyweight. For patients completing 1 year of drug treatment, mean weight loss was 16. 5 kg, or 16% of initial weight. Weight loss persisted for 2 years, but partial regain was seen at 3 years. The dropout rates were 18% at 6 months, 39% at 1 year, 68% at 2 years, and 78% at 3 years. At 1 year, blood pressure of hypertensive patients fell from 151/95 mm Hg to 127/78 mm Hg, and serum cholesterol and triglycerides of hyperlipidemic patients fell by 0. 750 mmol/L (29 mg/dL) and 0. 937 mmol/L (83 mg/dL), respectively. Adverse events were modest. We conclude that, in a private practice setting, long-term treatment of obesity with the combination of phentermine, fenfluramine, and a weight maintenance program is generally safe and effective. More research is needed to determine efficacy and safety for longer than 3 years.     

Abscission-inducing properties of methyl jasmonate, ABA, and ABA-methyl ester and their interactions with ethephon, AgNO3, and malformin

The biological activities of methyl jasmonate, ABA, methyl abscisate, and malformin were compared in a variety ofVigna radiata abscission tests. Although each compound diminished or completely negated the antiethylene properties of Ag⁺, differences in potency were observed. ABA and ABA-Me stimulated leaf abscission in the dark, potentiated abscission with low concentrations of ethephon, and interacted synergistically with malformin, whereas methyl jasmonate was inactive in each of these tests. Methyl jasmonate was most active in potentiating leaf abscission induced by high ethephon concentrations and stimulated petiole abscission, whether applied proximally or distally, from debladed explants. In two tests, negation of Ag⁺ activity and interaction with malformin, ABA concentrations as low as 0.1 M were biologically active and indicated that ABA can be a highly active abscission-inducing compound. Based on differences in biological activity, it was concluded that the modes of action of methyl jasmonate, ABA, and malformin were different.Journal Paper No. 9811 of the Purdue Agricultural Experiment Station.