Biomedical subjects
Publications and source records attributed to L Poirier.
1000 cataracts were cured thanks to surgery at the Ophthalmological Centre of BOPP in Dakar. The authors analyzed them according to several aspects (age, sex, aetiology and anatomical shape of the cataracts), according to the therapeutical results and complications. When having compared extracapsular and intracapsular, they stress the double problem of prevention and treatment of endophthalmia and of optical correction of aphakia at a health centre.
In this randomized prospective study the authors have compared the effectiveness and side-effects of two local vasoconstrictor agents, etilefrine (Effortil) and ornithine 8 vasopressin (Por 8) in vaginal gynaecological surgery. Thirty-three patients entered the trial and were divided into two groups: G1 (15 patients) received Effortil, and G2 (18 patients) received Por 8. The products, administered at random, were diluted in saline 40 ml and injected into the cervix through 6 points. A 3-minute interval was allowed between injection and incision. The results were assessed on the basis of trans- and postoperative haemorrhage and haemodynamic variations. Palor of the cervix was achieved after 3 minutes in both groups; moderate bleeding was observed in only one of the G1 patients. Postoperative renewal of packing was necessary in 2 patients in G1 and 4 patients in G2. No electrocardiographic anomaly was recorded in any of the two groups. Diastolic BP was significantly higher in G2 than in G1 (P less than 0.002, Fisher test). Systolic BP was also elevated in that group (P less than 0.03, chi 2 test). Moderate reduction in heart rate was observed in both groups (P less than 0.3, Fischer test), but severe (48 beats/min) bradycardia was noted in one G2 patient.
For immunocompetent patients, ocular toxoplasmosis is the most frequent infectious cause of chorioretinal inflammation. Nowadays, the laboratory diagnosis of ocular toxoplasmosis requires serological tests and anterior chamber puncture to detect the local production of specific antibodies. The authors describe a new technique to detect toxoplasma in aqueous humor by a polymerase chain reaction in which the target is a 88 bp specific rDNA fragment. 31 patients were concerned (23 highly suspect of ocular toxoplasmosis and 8 controls). The presence of the parasite in aqueous humor was found in 7 cases. No false positive was detected. The sensitivity of the test is reduced by the poor volume of the sample. The combination of this technique with Desmont's coefficient gives a better positive predictive value. We emphasize the pathophysiological value of this technique by suggesting the presence of tachizoites in the anterior chamber. According to our knowledge, this finding has never been demonstrated. In the future, this should be a very promising technique for the diagnosis of ocular toxoplasmosis.
The effects of long-term reduction in blood pressure by the angiotensin converting enzyme inhibitor captopril, as single therapy or in combination with hydrochlorothiazide (HCTZ), were compared with those of metoprolol and/or hydrochlorothiazide in 91 hypertensive non insulin-dependent diabetics with normal renal function. Following a single-blind placebo run-in period of 4 weeks, treatments were assigned randomly in a double-blind fashion. During the study, weight and glycosylated hemoglobin remained elevated. After 9 months of treatment, blood pressure fell significantly (p less than 0.0001) in all treatment groups, with most patients achieving goal supine diastolic blood pressure of less than or equal to 85 mmHg. Whereas urinary albumin excretion (UAE) did not change in patients given metoprolol and/or HCTZ, captopril monotherapy (p = 0.0021) or captopril given in combination with HCTZ (p = 0.0002) decreased UAE without affecting glomerular filtration rate. These data are in favour of a renal beneficial effect of angiotensin converting enzyme inhibitors distinct from their effects on systemic blood pressure. Further studies are needed to determine whether this effect persists with longer treatment, and whether it would lead to better preservation of kidney function than other antihypertensive agents.
The antihypertensive efficacy of sustained-release isradipine administered once daily compared to the immediate-release formulation administered twice daily was assessed by ambulatory blood pressure (BP) monitoring in a double-blind randomized crossover study in 76 mild-to-moderate hypertensive patients. Conventional BP and heart rate parameters were evaluated after a 4-week placebo period and patients qualified for entry if sitting diastolic BP was between 95 and 114 mm Hg. Ambulatory BP monitoring was measured at baseline and after active treatment with both formulations. The 2 regimens induced a significant and almost identical reduction (p less than 0.001) in the mean 24-hour BP without affecting heart rate. Isradipine was more effective in patients whose clinical hypertension was confirmed by ambulatory BP monitoring (35) than in patients who remained normotensive by ambulatory BP monitoring criteria (41). The isradipine-treated ambulatory hypertensive group experienced significantly greater decreases in BP during 24-hour, work, awake and sleep periods than did the ambulatory normotensive group. These data suggest that sustained-release isradipine has a sustained antihypertensive effect throughout 24 hours comparable to that of isradipine given twice daily and may improve compliance with long-term treatment. In addition, the results confirm the usefulness of ambulatory BP monitoring in determining truly hypertensive patients likely to respond to drug administration.
We compared the effects of diltiazem sustained-release formulation and metoprolol on diurnal ambulatory blood pressure (BP) and plasma lipoprotein levels. Forty-nine patients with primary hypertension were included in a randomized, double-blind, crossover study, and 44 completed the trial. Both diltiazem and metoprolol significantly lowered office (p less than 0.001) and diurnal ambulatory BP (p less than 0.01). After 16 weeks of therapy with diltiazem, mean ambulatory BP decreased 10/7 mm Hg, whereas metoprolol lowered BP by 16/10 mm Hg (p less than 0.001 for systolic BP and p less than 0.01 for diastolic BP). Moreover, metoprolol seemed to induce a greater reduction in morning BP at work. Although diltiazem had no effect on lipid levels, treatment with metoprolol was associated with a significant rise in triglyceride levels (p less than 0.001 vs baseline and diltiazem), total cholesterol levels (p less than 0.05 vs baseline), atherogenic index (p less than 0.05 vs baseline and diltiazem) and very low-density lipoprotein and cholesterol levels (p less than 0.001 vs baseline and diltiazem) and a significant decrease in high-density lipoprotein cholesterol levels (p less than 0.01 vs baseline and p less than 0.001 vs diltiazem). These data suggest that both diltiazem and metoprolol provide adequate office BP control. The deleterious effects of metoprolol on lipid and lipoprotein levels may counterbalance its beneficial effects on reduction of ambulatory BP.
The ability of methyl-deficient, amino-acid-defined diets to produce enzyme-altered foci was quantitatively determined in the livers of rats treated both with and without an initiating dose of diethylnitrosamine (DEN). Male weanling F-344 rats were fed a complete, amino-acid-defined diet for 1 week. They were then injected i.p. with a single dose of DEN (20 mg/kg body weight) and fed the complete diet for an additional week. Forty animals in each dose group were then maintained for 5-38 weeks on the complete diet (diet 1) or one of the three methyl-deficient diets customarily used in this laboratory: diet 2, devoid of methionine and choline; diet 3, devoid of methionine only; and diet 4, devoid of choline only. In diets 2 and 3, methionine was replaced by equimolar amounts of its metabolic precursor, DL-homocystine. Ten animals per group were killed 8, 12, 17, 24 and 41 weeks after DEN initiation. For 2 weeks prior to being killed, each group was maintained on the complete diet to minimize the histological abnormalities due to acute toxicity of the diets. Serial sections of the livers were obtained, stained sequentially for gamma-glutamyltranspeptidase, ATPase and glucose-6-phosphatase, and the quantitation of the focal lesions scored by these markers was carried out by quantitative stereology. The results indicated that, regardless of the enzyme marker(s) examined, there was a general correspondence between the volume and number of altered hepatic foci (AHF) formed and the previously described tumor-promoting activities of each diet. Thus, while all DEN-treated groups contained significant numbers of AHF 24 weeks after initiation, only the diet-2-fed animals displayed such foci at 8 weeks. Similarly, among the uninitiated rats, only those fed diet 2 exhibited the presence of AHF throughout the experimental period. Interestingly, the livers of uninitiated, choline-deficient rats showed a small number of AHF at 24 and 42 weeks; these foci were not observed at all in the corresponding DEN-untreated animals fed diet 3, deficient in methionine only. The results provide evidence that the carcinogenic effects of the methionine- and choline-deficient diet result more from its strongly promoting effect than from any initiating activity by the diet.
We compared the effects of sustained-release diltiazem and captopril on blood pressure control and lipid profile. Forty-eight patients with primary hypertension were included in this randomized, double-blind, crossover study and 43 completed the trial. Following a two-to four-week placebo run-in period, each patient initially received either diltiazem (60-180 mg twice daily) or captopril (25-75 mg twice daily) for 16 weeks and then crossed over to the other drug after an interim placebo washout period. Both drugs significantly reduced systolic (SBP) and diastolic (DPB) blood pressure compared to baseline. However, supine (P less than 0.01), sitting and standing (P less than 0.05) DPB was lower with diltiazem than with captopril. Moreover, BP control (sitting DBP less than 90 mmHg) was achieved in a greater proportion of patients treated with diltiazem (63 vs 44%). Heart rate was significantly reduced (P less than 0.001) with diltiazem in all positions but was unchanged with captopril. Lipid, lipoprotein and apolipoprotein concentrations were not modified with either treatment. We conclude that both diltiazem and captopril are effective antihypertensive agents without deleterious effects on lipid metabolism. However diltiazem provides a better prolonged control of BP and may offer some advantages for patients in whom a slower heart rate would be beneficial.
Mice of most strains show a genetically determined ability to reject foreign bone marrow grafts even after lethal irradiation. The effector cells mediating this resistance are spleen localised, lymphoid in morphology, and rapidly renewing. Two additional aspects of these cells were characterized in the present study, i.e., their sensitivity to: 1) anti-T cell and -B cell antibodies, and 2) the immunoregulator PGE2. T and B cell depleted splenocytes, or splenocytes from PGE2 pre-treated, highly resistant mice (C57Bl/6J) were transferred into irradiated, non-resistant secondary host mice (129/J) to establish whether or not they would retain their normally strong ability to spontaneously reject a third party (DBA/2) bone marrow allograft. In all cases, bone marrow seeding was assayed by enumerating the spleen colonies present in the secondary host 7 days after bone marrow grafting. Irradiated 129/J mice injected with low numbers (20 x 10(6) of untreated C57Bl/6J spleen cells prior to DBA/2 bone marrow contained 27.8 +/- 1.9 colonies/spleen, while mice injected with the same number of T and B depleted C57Bl/6J spleen cells contained significantly fewer (16.3 +/- 1.7) colonies/spleen. On the other hand, when C57Bl/6J spleen cells were incubated overnight with PGE2 prior to injection (20 x 10(6) into the 129/J hosts, they were unable to prevent the development of numerous colonies upon challenge with the DBA/2 bone marrow allograft (31.5 +/- 1.5 colonies/spleen: PGE2 pre-treated vs 16.9 +/- 2.1 colonies/spleen: non-pre-treated, control). The results demonstrate firstly, that spleen cells depleted of both Thy-1- and Ig-bearing cells appear to have concentrated for the effector cells responsible for bone marrow allograft rejection, and secondly, such effector cells could be suppressed by short-term exposure to PGE2, resulting in successful "take" of the bone marrow allograft.
This study provides basic data on the time of origin as well as on the spatio-temporal setting pattern of the neurons of the red nucleus, the inferior olivary complex and the cerebellar nuclei during ontogenesis of the rat brain. The first neurons of the olive form on day 12. In the adult they set in the rostral part of the dorsal accessory olive and in the minor subgroups associated with the medial accessory olive. On day 13, neurogenesis is intense in both divisions of the red nucleus, in all areas of the inferior olivary complex, in the medial and interpositus cerebellar nuclei and in the small-celled part of the lateral cerebellar nucleus. On day 14, neurogenesis is completed in the magnocellular division of the red nucleus and in the dorsal accessory olive but the neurons of the principal and medial accessory olives, of the rostral and caudal poles of the medial cerebellar nuclei, of the interpositus and lateral cerebellar nuclei as well as those of the parvocellular division of the red nucleus are still formed. Our study suggests that in the rat brain the neurons of the nuclei involved in the rubro (parvo)-olivo-cerebello-rubral and rubro (magno)-reticulo-cerebello-rubral loops develop on days 13 and 14 of gestation. Maturation, cytoarchitecture and phylogeny are also discussed.
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The photoreaction center from Rhodospirillum rubrum contains about 90% protein, 6% pigment, mere traces of lipids, and no cytochromes. It also contains at least 1 mol of ubiquinone and 1 iron atom per mol. Its three-component polypeptide chains were isolated by preparative electrophoresis, and their molar stoichiometry was established as 1:1:1. The amino acid composition of the photoreaction center from strain S1 and from its subunits is reported. The protein as a whole contains about 65% nonpolar residues, and the degree of hydrophobicity of its subunits is alpha less than beta less than gamma. The minimal molecular weight based on the extinction coefficient and on the amino acid content is 90 000. This corresponds to a half-cystine mole number of 6.
Lysine supplementation of the growth medium of a wild type strain of the yeast Saccharomycopsis lipolytica specifically results in saccharopine dehydrogenase repression. Starvation of the strain for histidine triggers a general depression of various histidine, leucine, arginine and lysine biosynthetic enzymes, including saccharopine dehydrogenase. These two types of control, specific and general, act independently on saccharopine dehydrogenase expression, since mutants which fail to respond to the specific control still are sensitive to the general one. These mutants were first selected as unable to catabolize lysine, suggesting that a link may exist between saccharopine dehydrogenase specific regulation and activity of the catabolic pathway.
1. A rapid method for estimating the activity of the first enzyme of lysine biosynthesis in yeasts (acetyl-coenzyme A: 2-ketoglutarate C-acetyl transferase, EC 4.1.3.21) is described. 2. In the wild type strain, the fixation of one substrate, S-acetyl coenzyme A, shows sigmoidal saturation kinetics. The initial rate experiments indicate that the reaction obeys an ordered mechanism, 2-ketoglutaric acid binding before S-acetyl coenzyme A. 3. The activity is completely inhibited in vitro by lysine and by some lysine analogs, which all show cooperative binding and have an heterotropic effect on 2-ketoglutaric binding sites. A second class of affectors is found, including 2-aminoadipic acid, pipecolic acid and dipicolinic acid, which all affect the cooperativity of S-acetyl coenzyme A binding sites. 4. Two types of mutations which modify these inhibition patterns without affecting the catalytic activity are described. One results in a desensitization towards lysine and lysine analogs only. The other entirely abolishes the susceptibility towards the second type of inhibitors, without affecting the susceptibility to lysine. 5. No variations of the specific activity could be detected in the wild type strain at all; mutants showing an increased or a reduced activity were isolated. 6. Our results do not support the existence of isoenzymes at the level of homocitrate synthetase in this yeast.
The antigenic composition of the soluble extract from normal human kidney was determined with the combined techniques of immunological absorption, immuno-diffusion and immunoelectrophoresis. The kidney extract contained at least eleven non-serum, tissue antigens; some of them were found in the extracts of other organs, but three were kidney-specific. None of the soluble tissue antigens from human kidney was characterized as a lipoprotein; however, three of them stained with the reagent for glycoproteins. Esterase activities were also demonstrated in four non-serum, renal antigens, one of which was present only in the kidney extract and absent in the other organs extracts.
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1. The activities of the purine phosphoribosyltransferases (EC 2.4.2.7 and 2.4.2.8) in purine-analogue-resistant mutants of Schizosaccharomyces pombe were checked. An 8-azathioxanthine-resistant mutant lacked hypoxanthine phosphoribosyltransferase, xanthine phosphoribosyltransferase and guanine phosphoribosyltransferase activities (EC 2.4.2.8) and appeared to carry a single mutation. Two 2,6-diaminopurine-resistant mutants retained these activities but lacked adenine phosphoribosyltransferase activity (EC 2.4.2.7). This evidence, together with data on purification and heat-inactivation patterns of phosphoribosyltransferase activities towards the various purines, strongly suggests that there are two phosphoribosyltransferase enzymes for purine bases in Schiz. pombe, one active with adenine, the other with hypoxanthine, xanthine and guanine. 2. Neither growth-medium supplements of purines nor mutations on genes involved in the pathway for new biosynthesis of purine have any influence on the amount of hypoxanthine-xanthine-guanine phosphoribosyltransferase produced by this organism.
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