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Biomedical subjects

S Haider

Publications and source records attributed to S Haider.

At least 19 recordsLinked to original sources
PubMed2003

Cyclic AMP level and phosphodiesterase activity during 17alpha,20beta-dihydroxy-4-pregnen-3-one induction and theophylline inhibition of oocyte maturation in the catfish, Clarias batrachus.

This study directly tested the hypothesis that the induction of oocyte maturation in the catfish Clarias batrachus is followed by a transient decrease in oocyte cyclic AMP (cAMP) level that is due to an increase in phosphodiesterase (PDE) activity. Further, the PDE inhibitor theophylline was used to investigate the possible role of PDE in the maturation-inducing action of 17alpha,20beta-dihydroxy-4-pregnen-3-one (17alpha,20beta-DP), the physiological maturation-inducing steroid of this catfish species. The results obtained from batches of oocytes taken from the same donor at the same time clearly show a close relationship between dose-dependent induction of germinal vesicle breakdown (GVBD) and PDE activity with a concomitant decrease in cAMP in the oocytes treated with different concentrations of 17alpha,20beta-DP. In contrast, theophylline prevents GVBD and inhibits PDE activity by promoting cAMP accumulation in oocytes. A time-dependent decrease in PDE activity and an increase in cAMP content with a marked inhibition of GVBD were recorded even in oocytes pre-stimulated with 1 microgram/ml 17alpha,20beta-DP for 6 h and then treated with 1 mM theophylline for various times. These results suggest that cAMP plays a key role in the regulation of oocyte maturation in C. batrachus which may be mediated by PDE activity.

Animals↗
PubMed2003

The effect of low sludge age on wastewater fractionation (S(S), S(I)).

In lab-scale experiments at the 2-stage activated sludge pilot plant of Vienna's central WWTP it is shown that the wastewater soluble COD concentration, which is inert to a sludge with SRT < 1 d (SI(A)) is about double compared to the S(I) concentration in sludge with SRT > 10 d (SI(B)). Unexpectedly the ratio of SI(A)/SI(B) is independent of the sludge age between SRTs of 0.4 and 1.0 days. The difference between the two S(I) fractions is soluble COD that is readily biodegradable by the sludge with SRT > 10 d. However, it is degraded at a lower maximum growth rate. These results comply with earlier results gained with different methods and at different WWTPs. It is hypothesised that very low sludge ages result in a selection of fast growing bacteria, which can utilise only part of the S(S) in the raw wastewater. The other part of S(S) therefore remains in the wastewater and can thus be utilised for enhanced denitrification in the second stage. It is still unknown beyond which sludge age the soluble inert COD SI(A) starts to decrease, finally reaching the value SI(B) for low loaded systems (SRT > 5 days). From this point on S(I) and S(S) are assumed only to depend on the wastewater composition and not on the sludge age. The assumption of the Activated Sludge Model No.1 that the biodegradable fractions can be modelled as a single substrate and by a single removal kinetic (one Monod term) appears not to be applicable for low sludge ages. Some suggestions for mathematical modelling, design and operation of 2-stage activated sludge systems are given.

Biodegradation, Environmental↗
PubMed2002

Role of cyclic AMP-dependent protein kinase in oocyte maturation of the catfish, Clarias batrachus.

The results of the present study demonstrate the probable involvement of adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase (PKA) in the regulation of oocyte maturation in the catfish, Clarias batrachus. A decrease in total PKA activity with a concomitant increase in the percentage of germinal vesicle breakdown (GVBD) was found in oocytes treated with different doses of N-(2-[p-bromocinnamylamino]ethyl)-5-isoquinoline sulfonamide (H-89), a selective, potent inhibitor of PKA and 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17 alpha, 20 beta-DP), the natural maturation-inducing steroid of this catfish. Evaluation of time-course of response to H-89 and 17 alpha, 20 beta-DP revealed that PKA activity decreased, and incidence of GVBD increased at all the time points when compared with their respective controls. The data further indicate that the decrease in PKA activity in H-89-treated oocytes was more prominent, but the induction of maturation was slower than that induced by 17 alpha, 20 beta-DP. Moreover, cyanoketone (CK), an inhibitor of steroidogenesis that blocks the salmon gonadotropin (SG-G100)-induced GVBD, failed to abolish the maturational effect of H-89, suggesting that H-89 directly promotes GVBD by reducing PKA activity in oocytes. Taken together, these results indicate that inhibition of PKA activity in the oocyte of C. batrachus is directly involved in the mechanism leading to oocyte maturation.

Animals↗
PubMed2001

Cephalic vein and hemodialysis fistula: surgeon's observation versus color Doppler ultrasonographic findings.

The aim of this study was to evaluate whether preoperative color Doppler ultrasonography improves immediate success rates of arteriovenous fistulas for dialysis. One hundred twenty-four patients with chronic renal failure underwent color Doppler ultrasonographic examination of both arms, including the cephalic vein, before arteriovenous fistula construction. Patients were randomly divided into 2 groups: A and B. In group A, there were 52 patients, and the surgeon planned to construct arteriovenous fistulas depending only on physical examination. In group B, which comprised 72 patients, surgeons performed arteriovenous fistula construction on sites labeled by color Doppler ultrasonography. In group A, of 52 patients who had surgery for arteriovenous fistula construction, 13 had fistulas that did not function. Among these 13 patients, 8 were found to have chronic thrombotic changes in the cephalic vein on color Doppler ultrasonography, and 5 had none of these changes. When we checked the color Doppler ultrasonographic findings, we noted that these 5 patients had decreased volume flow in the radial artery. On the whole, the arteriovenous fistulas worked in 39 patients (75%) and did not function in 13 patients (25%). In group B, surgeons followed the color Doppler ultrasonographic results. Of 72 patients who underwent the procedure, 68 patients (94.4%) had functioning fistulas, whereas 4 (5.6%) had fistulas that did not work. These 4 patients were found to have low volume flow in the radial artery. When both groups were compared by chi2 analysis, the difference was statistically significant (P = .002). Group B, in which patients were preoperatively evaluated by color Doppler ultrasonography, had a high success rate. We found that color Doppler ultrasonography is very helpful as a noninvasive procedure for this evaluation. Although many surgical clinics still perform arteriovenous fistula construction without the aid of color Doppler ultrasonographic findings, we think that the use of color Doppler ultrasonography should be emphasized before surgeons proceed with arteriovenous fistula construction.

Adult↗
PubMed2000

Rare complication of intestinal Crohn's disease: giant fibroid polyp.

A 25-year-old male patient who had a brother with Crohn's disease was referred to our clinic with bloody diarrhea and crampy abdominal pain. After a plain erect abdominal X-ray, enteroclysis was performed, followed by abdominopelvic CT. Besides the radiological features of CD, both enteroclysis and CT revealed a big polypoid filling defect in the small intestine. The patient was surgically treated and the histopathology of the specimen revealed a giant fibroid polyp superimposed on CD, an extremely rare complication heretofore unmentioned in the radiology literature. In this report we discuss the role of enteroclysis in the diagnosis of complicated cases of long-standing CD. In addition, we also shed light on the importance of both enteroclysis and CT, with their complementary findings, in the radiological diagnosis of rare complicated cases of CD.

Adult↗
PubMed2000

Subjective evaluation of the therapeutic value of laparoscopic adhesiolysis: a retrospective analysis.

BACKGROUND: Adhesions are believed to be one of the principal causes of chronic pelvic pain. Although there may be some discrepancy between the degree of adhesions and the severity of the symptoms, surgical adhesiolysis is still considered to be useful for the relief of pain. METHODS: A total of 187 patients who underwent laparoscopic adhesiolysis at the Medical University of Ulm, Germany, within a 2-year period were asked to rank their discomfort on a visual pain scale before surgery and up to 1 1/2 years postoperatively. RESULTS: In this retrospective study, we found that nearly one-third of patients suffered from functional irritations that were either ameliorated or completely relieved by laparoscopic adhesiolysis. When other causes of chronic pain (such as endometriosis) are excluded, the results show that most patients benefited from laparoscopic adhesiolysis. CONCLUSIONS: It appears that laparoscopic adhesiolysis is an effective therapeutic measure to relieve chronic pelvic pain. Therefore, adhesiolysis should be performed in all patients with chronic or intermittent pain, and a complete lysis of adhesions should be planned. However, since pelvic pain may have organic or functional causes other than adhesions, complete adhesiolysis in patients with persistent pelvic pain may be of only limited importance.

Adult↗
PubMed2000

beta-adrenoceptor antagonists reinitiate meiotic maturation in Clarias batrachus oocytes.

Effects of beta-adrenoceptor antagonists propranolol and alprenolol in the oocyte maturation of the catfish (Clarias batrachus) were investigated under in vitro. Cyclic AMP (cAMP) levels were also measured in the control, propranolol and phosphodiesterase (PDE) inhibitor treated oocytes. When full-grown folliculated oocytes were cultured in vitro in the presence of different concentrations of propranolol or alprenolol, both the substances induced germinal vesicle breakdown (GVBD) in a dose-dependent manner. The maturational effect of alprenolol at the concentration of 1.0 mM was similar to that of the 1.5 mM dose of propranolol inducing more than 88% GVBD. In the time course study, when the oocytes were treated with 1.5 mM propranolol or with 1.0 mM alprenolol for various times, both the antagonists induced more than 80% GVBD after 4 h of incubations and this induction gradually increased with the increased duration of treatments. On the other hand, 1.5 mM propranolol treatment caused a significant decrease in oocyte cAMP which was maintained upto the duration of the study (36 h). When the oocytes were first stimulated by 1.5 mM propranolol or 1.0 mM alprenolol for 4 h and then treated with various doses of cAMP or PDE inhibitors (IBMX and theophylline), all these substances effectively blocked beta-adrenoceptor antagonist-induced GVBD. Both these PDE inhibitors promoted the accumulation of cAMP in the oocytes. These results provide the first example of an existence of a cAMP-mediated mechanism of action of beta-adrenoceptor antagonists in the induction of oocyte maturation in fish.

Adrenergic beta-Antagonists↗
PubMed2000

Progressive multifocal leukoencephalopathy and idiopathic CD4+lymphocytopenia: a case report and review of reported cases.

Progressive multifocal leukoencephalopathy (PML) is a well recognized demyelinating neurological disorder caused by JC virus. Idiopathic CD4(+) lymphocytopenia (ICL) is a syndrome first described by the Centers for Disease Control and Prevention as a CD4(+) count <300 cells/mm(3) or a CD4(+) count that is <20% of the total T cell count on 2 occasions, with no evidence of human immunodeficiency virus (HIV) infection on testing, and absence of any defined immunodeficiency or therapy that depresses the levels of CD4(+) T cells. To the best of our knowledge, this is the third reported case of PML and ICL, and also the first reported case of the use of cidofovir to treat PML in a patient not infected with human immunodeficiency virus.

Antiviral Agents↗
PubMed2000

Cyclic AMP-mediated control of oocyte maturation in the catfish, Clarias batrachus (Bloch): effects of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one and phosphodiesterase inhibitors.

An increase in the percentage of germinal vesicle breakdown (GVBD) with a corresponding decrease in cAMP was found in the oocytes which were incubated for 36 hr with different concentrations of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-DP). At its highest concentration (1 microgram/ml), 17 alpha,20 beta-DP induced 91.9 +/- 2.3% GVBD and decreased cAMP level to 0.8 +/- 0.1 pmol/oocyte from 2.9 +/- 0.2 pmol/oocyte (control). The two different known inhibitors of phosphodiesterase viz. 3-isobutyl-1-methyl-xanthine (IBMX) and theophylline inhibited GVBD in vitro and promoted the accumulation of cAMP in a dose-dependent manner irrespective of whether the oocytes were treated for a short duration (2 hr) or for a long duration (36 hr). Evaluation of time course response to 1 mM IBMX or 1 mM theophylline revealed that cAMP levels increased at all the time points when compared with their respective controls and blocked maturation. In contrast, 1 microgram/ml 17 alpha,20 beta-DP not only induced oocyte maturation but also caused an immediate decrease in cAMP within the first 2 hr (from 3.2 +/- 1.3 to 1.3 +/- 0.1 pmol/oocyte) of incubation which was maintained till the end of experiment (36 hr). Likewise, a significant inhibition of GVBD and accumulation of cAMP was recorded even in oocytes pre-stimulated with 1 microgram/ml 17 alpha,20 beta-DP for 6 hr and then treated with different concentrations of IBMX or theophylline. Taken together, these data strongly suggest that in C. batrachus a decrease of oocyte cAMP concentration is a prerequisite for the induction of oocyte maturation, and its increase is associated with the maintenance of meiotic arrest.

Animals↗
PubMed1998

Partial purification of maturation-promoting factor from catfish, Clarias batrachus: identification as the histone H1 kinase and its periodic activation.

Maturation-promoting factor (MPF) has been demonstrated in the 100,000 g supernatant of 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17 alpha, 20 beta-DP)-induced catfish, Clarias batrachus oocytes using DEAE-cellulose and sephadex G-200 chromatography. Partially purified MPF molecule eluted as a single peak on sephadex G-200 with molecular mass of approximately 200 kDa in native PAGE. SDS-PAGE analysis showed the presence of five proteins of 32, 34, 45, 46 and 48 kDa. Antibody against the PSTAIR sequence of p34cdc2 recognized 32 and 34 kDa proteins, whereas rabbit anti-cyclin B1 and B2 crossreacted with 46 and 48 kDa proteins, respectively. Cyclin B was absent in immature oocytes and appeared after 7 h of 17 alpha, 20 beta-DP stimulation, coinciding with the histone H1 kinase (HH1K) activity and start of germinal vesicle breakdown (GVBD). Our data indicate that C. batrachus MPF is a complex of cdc2 kinase and cyclin B molecules. A close relationship between HH1K activity and catfish oocyte maturation has been demonstrated using cycloheximide, cytochalasin B and colchicine. HH1K activation was inhibited by cycloheximide, while cytochalasin B and colchicine were ineffective. These finding suggests that the activation of HH1K depends on protein synthesis, whereas disruption of microfilaments influences only nucleus migration without effect on GVBD or HH1K activation. An increase of phosphorylated proteins after activation of catfish oocytes with 17 alpha, 20 beta-DP has also been observed.

Animals↗
PubMed1996

Food restriction decreases serotonin and its synthesis rate in the hypothalamus.

Rats fed on a restricted feeding (RF) schedule of 4 h day-1 to produce a 15-20% reduction in body weight were killed before (starved) and after (fed) the presentation of food on the sixth day to compare 5-hydroxytryptamine (5-HT; serotonin) metabolism and synthesis rate in the hypothalamus with freely feeding (FF) controls. The RF rats showed lower 5-HT concentration and synthesis rate than FF controls. Restricted feeding did not decrease tryptophan concentration in the hypothalamus. However, RF-fed rats had lower tryptophan concentration than RF starved rats. 5-HIAA concentration was comparable in RF fed rats and FF controls but higher in RF starved rats. Possible implications of the findings in the pathogenesis of the food deprivation/starvation-related disease anorexia nervosa are discussed.

5-Hydroxytryptophan↗
PubMed1996

The in vitro effects of forskolin, IBMX and cyanoketone on meiotic maturation in follicle-enclosed catfish (Clarias batrachus) oocytes.

The effects of an adenylate cyclase activator (forskolin, FK), phosphodiesterase inhibitor (3-isobutyl-l-methyl-xanthine, IBMX) and an inhibitor of steroidogenesis (cyanoketone, CK) on germinal vesicle breakdown (GVBD) in the catfish (Clarias batrachus) were investigated in vitro. In most of the experiments GVBD was induced by using 1 microgram/ml 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-DP), which is the maturation-inducing steroid (MIS) for this species. Adenosine 3':5'-cyclic monophosphate (cAMP) levels were also measured in the control, MIS-induced and/or FK- and IBMX-treated follicle-enclosed oocytes. MIS-induced GVBD was inhibited by FK (> or = 0.5 microM) or IBMX (> or = 1.0 mM), but oocyte exposed to 0.1 microM FK or 0.5 mM IBMX, after MIS stimulation, underwent GVBD. However, an inhibition of GVBD was recorded when the MIS-induced folliculated oocytes were preincubated with CK (1 microgram/ml) and subsequently treated with 0.1 microM FK. In the time course study, when the oocytes were stimulated by MIS for various time intervals and then treated with 1.0 microM FK or 1.0 mM IBMX, both the substances blocked maturation if they were added up to 12 hr after MIS. The extent of inhibition was gradually decreased and was completely removed after 30 hr of post-MIS stimulation. The stimulatory dose of 17 alpha,20 beta-DP (1 microgram/ml) not only induced GVBD (83.2 +/- 1.50%) in vitro but also reduced oocyte cAMP level (65.3 +/- 2.85 pmol/100 micrograms protein) significantly after 6 hr of incubation. However, FK (10.0 microM) or IBMX (1.0 mM) countered these effects and promoted the accumulation of cAMP in the oocytes; FK being more potent. On the other hand, when unstimulated full-grown but immature oocytes were cultured in vitro in the presence of different concentrations of FK, an induction of oocyte maturation was recorded in dose- and time-dependent manner. These results strongly suggest the involvement of cAMP in the regulation of catfish oocyte maturation.

1-Methyl-3-isobutylxanthine↗
PubMed1996

Seizure control: how to use the new antiepileptic drugs in older patients.

Three new antiepileptic drugs--vigabatrin, gabapentin, and lamotrigine--provide alternatives in the management of older patients with refractory partial seizures. Each appears to have a unique mechanism of action. Clinical trials indicate that routine lab monitoring is not necessary for the safe and effective use of these drugs. They also do not induce liver enzymes or alter the metabolism of other antiepileptic drugs, thus minimizing the risk of interactions. Potential side effects of these agents include dizziness, somnolence, and other signs of CNS depression.

Acetates↗
PubMed1995

Effects of cyproterone acetate on FSH and testosterone influenced spermatogenesis, steroidogenesis and epididymis in the Indian wall lizard, Hemidactylus flaviviridis (Ruppell).

The effects of FSH, testosterone and either cyproterone acetate (CPA) alone or in combination with FSH or testosterone on testis and epididymis in male lizards were studied histologically and histochemically during recrudescent phase to find out whether the onset of spermatogenesis is androgen dependent or FSH dependent. The testes of control lizards consisted of mainly spermatogonia, a few primary spermatocytes and secondary spermatocytes rarely. The interstitial or Leydig cells were atrophied. FSH treatment induced spermatogenic activity substantially as indicated by increase in number of primary and secondary spermatocytes and transformation of secondary spermatocytes into spermatids and into spermatozoa in a few cases. Besides, steroidogenic activity was also remarkably stimulated as evidences by considerable depletion of sudanophilic lipid and an increase in Delta5-3beta-hydroxysteroid dehydrogenase enzyme activity in Leydig cells. However, testosterone treatment resulted in the inhibition of spermatogenesis. A significant inhibition of spermatogenesis was noted in lizards treated either with CPA alone or in combination with FSH. The inhibitory effect of CPA on spermatogenesis was increased when it was given in combination with testosterone. The results indicate that onset of spermatogenic activity is dependent on FSH (or FSH-like protein), but not on the androgen. The ductus epididymidis in control lizards was regressed with low cuboidal epithelium. The lumen of the tubules was totally devoid of secretory material and spermatozoa. FSH treatment induced a marked hypertrophy in epididymidis. The lumen became filled with secretory material mixed with spermatozoa. The hypertrophy in epididymidis was also recorded after the treatment with testosterone, but the degree of induction was not to that extent as noted in FSH treated ones. However, CPA injected either with FSH or with testosterone resulted in the profound atrophy in epididymidis.

Animals↗
PubMed1995

Self medication or self care: implication for primary health care strategies.

To determine the frequency of self-medication, a cross-sectional study was conducted in a Karachi district by selecting households through systematic random sampling. Health seeking behaviour for childhood illnesses and assessment of the magnitude and reasons for self-medication were done by interviewing mothers/caretakers. Five hundred households were visited, of which 158 fulfilled the criteria of having one sick child in the previous month. Medication without prescription was given to 51.3% children, mostly consisting of unidentified drugs or analgesics/antipyretics. Good past experience (61.3%) with the medicine was the main reason for self-medication. The use of medicines by health professionals was the main reason influencing parents for self-medication to their children. Self-medication is difficult to eliminate, but interventions can be made to discourage use of inappropriate and harmful drugs.

Child↗
PubMed1994

Risk factors for drug misuse in Pakistan.

While a number of risk factors have been identified for drug misuse in the United States, little evidence is available about such factors in other societies. This study attempted to identify risk factors in Pakistan. Ten of 11 sociodemographic variables which had previously been identified as predictors in the United States successfully differentiated groups of addicts and controls in Pakistan. About 97% of the 60 addicts studied were at risk on four or more factors; 100% of controls were at risk on four or fewer factors. It appears that the precursors for misuse cut across cultural lines.

Adolescent↗
PubMed1993

Optic neuropathy in uraemic patients on dialysis.

Optic nerve disease has been reported in patients with renal failure. A toxic aetiology has been postulated. The incidence of this complication of renal failure has not been determined. We observed 60 patients with renal failure on dialysis for 24 months to determine the incidence of optic neuropathy. Four patients developed typical acute ischaemic optic neuropathy. Their case notes were reviewed in order to determine the pathogenesis. Each patient had long-standing renal failure and its sequelae of anaemia and hypertension. The immediate causes of ischaemia were hypotension in 1, severe anaemia in 1, and generalised atherosclerosis in 2 patients.

Adult↗