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M Ishaque

Publications and source records attributed to M Ishaque.

At least 19 recordsLinked to original sources
PubMed1992

Differential cardiovascular effects of propranolol, atenolol, and pindolol measured by impedance cardiography.

We have evaluated Sramek's method of impedance cardiography as a non-invasive way of detecting the cardiovascular effects of drugs. We made cardiovascular measurements using the method during passive tilting and exercise 2 h after the oral administration of atenolol (50 and 100 mg), propranolol (40 and 80 mg), pindolol (5 and 10 mg), and placebo in seven separate studies involving eight healthy male volunteers. Equivalent doses of the pure antagonists atenolol (beta 1) and propranolol (beta 1, beta 2) produced similar reductions in heart rate, systolic blood pressure, and cardiac index, and increases in stroke volume and total peripheral resistance, particularly during exercise. In contrast the partial agonist pindolol produced increases in heart rate and cardiac index, and reductions in peripheral resistance at rest. During passive tilting and exercise pindolol reduced heart rate, but cardiac output and total peripheral resistance were unchanged except at the highest levels of exercise. The similar cardiovascular effects of atenolol and propranolol, but differing effects of pindolol, are consistent with reports using other methods of measurement. This suggests that impedance cardiography may have a place in the non-invasive assessment of the cardiovascular effects of drugs.

Adult↗
PubMed1992

Energy generation mechanisms in the in vitro-grown Mycobacterium lepraemurium.

Mycobacterium lepraemurium was cultivated on Ogawa egg-yolk medium and its energy coupling mechanisms were investigated. Cell-free extracts prepared from in vitro-grown cells catalyzed phosphorylation coupled to the oxidation of generated NADH, added NADH, and succinate-yielding ratios of phosphorus moles incorporated into high-energy bonds to oxygen atoms utilized (P/O ratios) of 0.75, 0.52, and 0.36, respectively. Ascorbate oxidation alone or in the presence of tetramethyl-p-phenyline-diamine (TMPD) did not yield any adenosine triphosphate (ATP). However, ascorbate in the presence of added cytochrome c was coupled to ATP synthesis and yielded a P/O ratio of 0.12. The oxidative phosphorylation was uncoupled by all of the uncouplers used without any inhibition of oxygen consumption. ATP generation coupled to NADH oxidation was completely inhibited by the flavoprotein inhibitors, such as rotenone and amytal; these inhibitors had no effect, however, on ATP synthesis associated with succinate oxidation. Antimycin A or 2-n-heptyl-4-hydroxy-quinoline-N-oxide (HQNO) and cyanide inhibited markedly the oxidations of NADH and succinate as well as the coupled ATP generation. The phosphorylation coupled to ascorbate plus cytochrome c was not affected by either of the flavoprotein inhibitors or by antimycin A or HQNO, but was completely inhibited by cyanide. The thiol-bearing agents p-chloromercuribenzoate (PCMB) and N-ethylmaleimide were the potent inhibitors of the phosphorylation associated with the oxidation of NADH and succinate. The results indicate that the three energy-coupling sites are functional in the respiratory chain of in vitro-grown M. lepraemurium.

Adenosine Triphosphate↗
PubMed1992

Palmitate oxidation by in vivo and in vitro grown Mycobacterium lepraemurium.

Oxidation of palmitate by Mycobacterium lepraemurium isolated from C3H mice lepromata (in vivo) and also grown on Ogawa egg-yolk medium (in vitro) was investigated. Palmitate was found to be oxidized, after a lag period of about 8 h, by both the in vivo and in vitro grown bacilli. Cell-free extracts prepared from in vivo and in vitro grown cells catalysed an active oxidation of palmitate after a lag period of 3-4 h. The amount of ATP increased, with the increase in time during oxidation of palmitate by the cell-free extracts. The generation of ATP was strongly inhibited by the inhibitors rotenone, antimycin A and cyanide as well as by the uncouplers 2,4-dinitrophenol and 2,6-dibromophenol. These results indicated that oxidation of palmitate by the in vivo and in vitro grown M. lepraemurium is mediated through the respiratory chain using oxygen as the terminal electron acceptor.

Adenosine Triphosphate↗
PubMed1990

Microbiological aspects of aerobic thermophilic treatment of swine waste.

A thermophilic strain (D2) identified as a Bacillus sp. was isolated from an aerobic digestor of swine waste after several months of operation at 55 degrees C. Aerobic thermophilic batch treatment of swine waste inoculated with strain D2 was studied in a 4-liter fixed-bed reactor. Stabilization of the waste was achieved in less than 30 h when the original chemical oxygen demand (COD) was between 15 and 20 g/liter or in less than 48 h when the COD was around 35 g/liter. When the COD was higher than 30 g/liter, the pH of the waste reached 9.2 to 9.5 during the treatment, and periodic adjustment of the pH to 8.5 was necessary to maintain the activity of the biofilm. In this reactor, ammoniacal nitrogen was completely eliminated by desorption in less than 72 h of incubation. The different packing materials used resulted in similar rates of degradation of organic matter. The thermophilic treatment was also efficient in the 75-liter digestor, and stabilization was achieved in approximately 50 h. A bank of 22 thermophilic bacterial strains originating from different environments and adapted to the thermophilic treatment of swine waste was established. This thermophilic treatment allows, in one step, rapid stabilization of the waste, elimination of the bad smell, and complete elimination of ammonia nitrogen by stripping.

Aerobiosis↗
PubMed1990

Nitrification of swine waste.

Complete oxidation of ammonia nitrogen (approximately 1000 mg/L) to nitrite was observed in stabilized swine waste after 49 days in incubation at 400 rpm and 29 degrees C, only if 10% (v/v) activated sludge from a wastewater treatment unit and 1.5% (w/v) CaCO3, were added. Stabilized swine waste contains less than 0.09 most probable number (MPN) per millilitre of nitrosobacteria and 2.3 MPN/mL of nitrobacteria. In activated sludge, the concentrations of these bacteria were 2.4 MPN/mL for nitrosobacteria and 4.2 x 10(5) MPN/mL for nitrobacteria. In the swine waste where ammonia was oxidized to nitrite, the nitrosobacteria growth increased to 5.5 x 10(5) MPN/mL, while the nitrobacteria growth decreased to 2.3 MPN/mL. Inoculation of a freshly stabilized swine waste with 10% (v/v) of the active nitrifying waste and addition of 1.5% (w/v) CaCO3, accelerated the oxidation of ammonia nitrogen to nitrite; the reaction was completed after only 5 days of incubation. Increasing the incubation period to 10 days resulted in the complete oxidation of the accumulated nitrite to nitrate. In the stabilized swine waste, complete nitrification without accumulation of nitrite was obtained in only 5 days of incubation when the waste was inoculated with both enriched nitrifying populations (10(6)-10(7) MPN/mL).

Animals↗
PubMed1990

Growth of Mycobacterium leprae under low oxygen tension.

Despite numerous attempts, Mycobacterium leprae has yet to be cultivated in vitro. This organism has been considered as microaerophilic. The effects of various known gas mixtures on the in vitro growth of M. leprae were investigated. A gas mixture containing 2.5% O2 and 10% CO2 was found to be more favourable for the growth of this mycobacterium on artificial medium. Growth was evaluated by three parameters namely cell counts, bacterial ATP and DNA. An optimal growth of M. leprae, as determined by all three parameters, on both liquid and solid media was obtained between 18 and 24 weeks of incubation under optimal gas mixture. Solid medium which contained egg-yolk was relatively more beneficial for in vitro growth than the liquid medium. The cultivated bacilli exhibited some important characteristics specific for M. leprae, including growth in mouse foot-pads. The bacilli gradually lost their power of adaptation to grow on artificial media and did not show any ATP or DNA after about 36 weeks of incubation.

Adenosine Triphosphate↗
PubMed1989

Direct evidence for the oxidation of palmitic acid by host-grown Mycobacterium leprae.

Oxidation of palmitic acid by whole-cell suspensions of Mycobacterium leprae free from host tissues was investigated using manometric techniques. After a lag period of about 6-8 h, M. leprae suspensions catalysed an active oxidation of palmitic acid, and the oxidative process (oxygen uptake) was quite sensitive to rotenone, atabrine, amytal, antimycin A and cyanide. The spectrophotometric observations indicated that the M. leprae cytochrome system, under anaerobic conditions, was reduced in the presence of palmitic acid which was completely oxidized by oxygen. These data provide direct evidence that M. leprae cells are capable of oxidizing palmitic acid, and that oxidation is mediated by the electron transport system using oxygen as the terminal electron acceptor.

Animals↗
PubMed1989

Duodenal and antral mucosal prostaglandin E2 synthesis in a study of normal subjects and all stages of duodenal ulcer disease treated by H2 receptor antagonists.

We tested the hypothesis that the production of prostaglandin E2 (PGE2) is impaired in duodenal ulcer disease and affected by treatment and healing. This was investigated by a study of maximal PGE2 synthesis rates in duodenal and antral mucosal biopsies obtained at endoscopy. The patients were divided into three groups. Group (a): endoscopically normal controls (n = 56); group (b): treatment controls (non-DU disease: gastric ulcer or oesophagitis treated by histamine H2 receptor antagonists) (n = 41); and group (c): patients with DU disease (n = 183) further subdivided into group (c1) active ulcer not on treatment (n = 47), (c2) treated active ulcer (n = 35), (c3) healed ulcer on treatment (n = 86), and (c4) healed ulcer not on treatment (n = 15). Group (a) synthesised (mean (SD] 106.6 (39.0) pg PGE2/mg wt of tissue from the duodenal bulb and 129.9 (56.9) from the second part of the duodenum. No difference was found between group (a) and (b) at either site. Group (c1) ulcer rim made 49.8 (22.7) and at all stages ulcer rim and scar made less than the control duodenal bulb (p less than 0.02). Uninvolved duodenal bulb form groups (c1) (63.4 (31.0], (c2) (83.6 (38.5], and (c3) (81.5 (31.1], however, also made significantly less than controls (p less than 0.02) and a similar though non-significant trend was seen in group (c4). Biopsies from the second part of the duodenum did not synthesise significantly less than the control group but a similar trend was noticed at each stage of ulcer treatment. Biopsies of control antrum synthesised 124.5 (32.2) but only 93.7 (44.2) in group (cl) (p < 0.005). All stages of duodenal ulcer healing were associated with a decreased capacity to synthesise the major prostaglandin PGE2 at the ulcer site and the uninvolved duodenal bulb and, in acute untreated duodenal ulcer, the uninvolved antrum. This decreased capacity may be the consequence of the disease process itself and not secondary to the treatment, indicating a basic pathophysiological abnormality which may explain the characteristic tendency of the disease to relapse.

Adult↗
PubMed1984

Cytochrome system in cultivated Mycobacterium lepraemurium.

The respiratory pigments of cell suspensions of Mycobacterium lepraemurium cultivated on Ogawa egg-yolk medium were investigated spectrophotometrically. The results obtained showed that whole cell suspensions of both Kumato and Hawaiian strains contained flavins, cytochromes of the a2 and b type, as well as a CO-binding pigment similar to cytochrome o. The whole cell suspensions of M. lepraemurium did not show detectable quantities of c type cytochrome. However, cytochrome c was present in small amounts, and its presence became evident in the dithionite-reduced minus oxidized difference spectra of pyridine haemochromogens prepared from in vitro grown cells of M. lepraemurium.

Carbon Dioxide↗
PubMed1983

Impairment of virulence of in vitro subcultures of Mycobacterium lepraemurium.

Mycobacterium lepraemurium was cultivated in vitro on Ogawa egg-yolk medium. The pathogenicity of the third and eighth subcultures for C3H and C57BL mice was compared with that of in vivo grown murine bacilli by evaluating the mean survival time of infected mice. The results strongly suggest that a significant drop of virulence occurs during the in vitro cultivation of M. lepraemurium.

Animals↗
PubMed1983

Respiratory activities of in vitro grown Mycobacterium lepraemurium.

Mycobacterium lepraemurium was cultivated on Ogawa egg-yolk medium and its respiratory activities using several substrates were investigated. Glycerol and succinate were oxidized at a slow rate by the cell-free extracts prepared from in vitro grown Hawaiian and Keishicho strains of M. lepraemurium. None of the other intermediates of the glycolysis cycle as well as of the tricarboxylic acid cycle was oxidized by the whole cell suspensions or cell-free extracts. Likewise, many sulfur compounds such as cystine, mercaptosuccinate, monothioglycerol, thioacetate, etc., were inactive. However, sulfhydryl compounds such as L-cysteine, D-cysteine, DL-cysteine, dithioerythritol, dithiothritol, and DL-penicillamine were actively oxidized. Yeast extract was also readily oxidized by cell suspensions of in vitro grown M. lepraemurium. Tween 80 was very poorly oxidized by whole cell suspensions but the cell-free preparations catalyzed an active oxidation of Tween 80. While bovine serum albumin was oxidized at a slow rate by cell-free extracts, egg albumin was inactive. The thiol-binding agents, p-hydroxymercuribenzoate and N-ethylmaleimide were effective inhibitors of succinate and NADH oxidation, thus indicating the involvement of sulfhydryl compounds in the metabolism of M. lepraemurium.

In Vitro Techniques↗
PubMed1982

[Pathogenicity in the rat of Mycobacterium lepraemurium cultivated in vitro].

The pathogenicity in Sprague-Dawley rats of Mycobacterium lepraemurium cultivated on egg-yolk medium was investigated. The results show that in vitro grown cultures provoked hugh subcutaneous lepromata in rats similar to those produced by the in vivo grown M. lepraemurium. The acid-fast bacilli isolated from lepromata of rats infected with the in vitro or in vivo grown cultures were microscopically and histopathologically identical to each other.

Animals↗
PubMed1982

Mycobacteria of Mycobacterium scrofulaceum type isolated from rat or mice lepromata are not the aetiologic agents of murine leprosy.

Mycobacterial strains M.M4 and M.EY3 were isolated from a mouse leproma, respectively, on Kl-1 and Ogawa egg-yolk medium. Strain M.M4 was scotochromogenic and produced a yellow pigment. Young cultures were non-acid-fast and became acid-fast during the exponential growth phase. Primary cultures of strain M.M4 did not grow on conventional culture media. However, the subcultures grown in Kl-1 medium were easily subcultured in the homologous media as well as on Lowenstein, Sauton and Dubos media. Cultures M.M4 were insensitive to isoniazid and p-nitrobenzoic acid. Both scotochromogenic strains M.R56 and M.M4 did not produce murine leprosy disease in susceptible animals like BALB/C and C3H mice. Primary as well as the subcultures of strain M.EY3 grew only on the Ogawa egg-yolk medium. Colonies of this strain were creamy white and unlike other mycobacteria, produced rust-like brown spots on the medium at the sites of colonies. In vitro grown cultures M.EY3 were sensitive to isoniazid and p-nitrobenzoic acid. BALB/C and C3H mice infected with M.EY3 cultures developed lepromata similar to those produced by the in vivo grown M. lepraemurium. Both M.R56 and M.M4 scotochromogenic cultures grown in liquid Kl-1 medium are not the causative agents of murine leprosy. On the other hand, cultures M.EY3 grown on Ogawa egg-yolk medium possess characteristics similar to M.lepraemurium and are, in fact, the aetiologic agents of murine leprosy.

Animals↗
PubMed1981

In vitro cultivation of Mycobacterium lepraemurium and its identification by animal inoculation.

The primary in vitro cultures from lepromata of mice or rats previously infected with the Hawaiian strain of Mycobacterium lepraemurium were obtained on Ogawa egg-yolk medium at 34 degrees C in approximately 90 days of incubation. Optimal growth of subcultures was achieved in 40 to 60 days of incubation and such cultures were used to test their pathogenicity in animals. The in vitro grown subcultures provoked in mice subcutaneous lepromata identical to those produced by the in vitro grown M. lepraemurium. Also, mice infected subcutaneously and intravenously with the in vitro grown subcultures developed lesions in livers, spleens, and kidneys similar to those of mice infected with the mouse passage murine leprosy bacilli. Microscopically and histopathologically, the acid-fast bacilli derived from organs infected with the in vitro or in vivo grown cultures were indistinguishable from each other.

Animals↗
PubMed1981

Energy coupling mechanisms in host-grown Mycobacterium lepraemurium.

Energy coupling mechanisms of Mycobacterium lepraemurium isolated from Sprague-Dawley rats lepromata were investigated. Cell-free extracts catalyzed phosphorylation coupled to the oxidation of generated NADH, added NADH, and succinate yielding P/O ratios of approximately 0.8, 0.6, and 0.4, respectively. Ascorbate oxidation alone or in the presence of cytochrome c or N,N,N',N'-tetramethyl-p-phenylenediamine was not coupled to ATP synthesis. The oxidative phosphorylation was completely uncoupled by 2,4-dinitrophenol, 2,6-dibromophenol, pentachlorophenol, m-chlorocarbonylcyanide phenylhydrazone, dicumarol, and gramicidin at concentrations which did not cause any inhibition of oxygen uptake. While the NADH oxidation and associated phosphate esterification was markedly sensitive to rotenone and other flavoprotein inhibitors, these inhibitors had no effect, however, on the phosphorylation coupled to succinate oxidation. The respiratory chain inhibitors such as antimycin A or 2-n-heptyl-4-hydroxyquinoline-N-oxide, and cyanide were the potent inhibitors of the phosphorylation associated with the oxidation of NADH and succinate. The ATP formation coupled to the oxidation of NADH and succinate was also inhibited by oligomycin as well as by the thiol-binding agents, p-hydroxymercuribenzoate and N-ethylmaleimide. The results indicated that NADH and succinate oxidation by in vivo grown M. lepraemurium was mediated by oxidative enzymes involving first and second energy coupling sites.

Adenosine Triphosphate↗