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Biomedical subjects

F A Khan

Publications and source records attributed to F A Khan.

At least 91 records · Page 5Linked to original sources
PubMed1996

Involvement of corticosteroid-like neurosteroids in pentobarbital-induced sleep.

Recent reports have confirmed the involvement of neurosteroids in a number of neurophysiological processes, including sleep, and that these compounds interact with the gamma-aminobutyric acid receptor A complex. As many of the behavioural effects of pentobarbital are as a result of the activity at this complex, we investigated the role of corticosteroid-like neurosteroids in regulation of sleep, using metyrapone as a tool. Metyrapone, a blocker of the enzyme 11 beta-hydroxylase, which is essential for the biosynthesis of corticosteroids, when administered intracerebroventricularly (i.c.v.) at low doses (50-5000 ng) caused a dose-dependent reduction in sleep time induced by pentobarbital. This effect was, however, antagonized by concomitant administration of anti-corticotropin-releasing factor antisera. The present study reveals for the first time that corticosteroid-like neurosteroids might be involved in the regulation of CNS excitability.

Adrenal Cortex Hormones↗
PubMed1996

cDNA cloning and characterization of an atrophin-1 (DRPLA disease gene)-related protein.

Dentatorubral and pallidoluylsian atrophy (DRPLA) is a progressive neurological disorder characterized by neuronal degeneration, especially in the cerebellar dentate nucleus. DRPLA is caused by an unstable expansion of a CAG trinucleotide repeat coding for glutamine in a gene of unknown function, termed atrophin-1, located on chromosome 12. To gain additional understanding of atrophin-1, we have isolated a second member of the atrophin-1 gene family by screening rat cDNA libraries. The 1006-amino-acid product of this gene, which we have termed rat atrophin related protein(rARP), does not contain a glutamine repeat, but it does contain two regions of alternating acidic and basic amino residues similar to those found in atrophin-1. rARP is widely expressed as both a 7.4- and a 9.4-kb message, with enrichment in cerebellum and testis. Like atrophin-1, the rARP in vitro translation product migrates more slowly on SDS-polyacrylamide gel electrophoresis than predicted by molecular weight. We conclude that, at least in the rat, polyglutamine is not an essential feature of the atrophin family of genes.

Amino Acid Sequence↗
PubMed1996

Generalized joint hypermobility as a factor in clicking of the temporomandibular joint.

Twenty-six patients with clicking or locking of the temporomandibular joint (TMJ) and 28 age- and sex-matched controls were assessed for generalized joint hypermobility by BEIGHTON's method. Function of the masticatory apparatus was measured with FRICTON's Craniomandibular Index. The TMJ patients had significantly higher joint mobility scores, but within the patient group there was no correlation between either the dysfunction or palpation scores and the hypermobility scores. The findings are interpreted as supporting multiple causes of TMJ internal derangement, one of which is a systemic joint factor.

Adolescent↗
PubMed1996

Thrombotic thrombocytopenic purpura in HIV infection: a report of two cases.

Thrombotic thrombocytopenic purpura (TTP) is a rare but well-described complication of HIV infection, which occurs equally frequently during the early asymptomatic phase of HIV infection and with clinical AIDS. The clinical spectrum varies from a low-grade asymptomatic thrombocytopenia with mild renal insufficiency to a catastrophic illness with gross neurological deficits and renal failure requiring dialysis. We report two cases of TTP associated with HIV infection seen in our institution over a period of 2 years. The clinical course of these two patients highlights the markedly heterogeneous characteristics of patients with HIV-related TTP. HIV infection may be the most common association of TTP in certain communities with a high prevalence of HIV infection. As early diagnosis and institution of plasmapheresis is crucial for a favorable outcome it is important to be aware of this association.

Acute Kidney Injury↗
PubMed1996

The effect of increasing the dose of buprenorphine on the haemodynamic response associated with tracheal intubation.

The effect of buprenorphine on the haemodynamic response to tracheal intubation was studied at two dose levels, 2.5 micrograms.kg-1 and 5 micrograms.kg-1, in a placebo-controlled double-blind trial in 75 patients undergoing laparoscopic cholecystectomy. The study drugs were administered intravenously 8 min before induction of anaesthesia with thiopentone 5 mg.kg-1 and vecuronium 0.1 mg/kg-1. Buprenorphine 2.5 micrograms.kg-1 caused 50% attenuation of the blood pressure response whereas 5 micrograms/kg-1 caused 70% attenuation compared to the saline placebo. The maximum increase in heart rate was 14% of the control value after 2.5 micrograms.kg-1 and 11% after 5 micrograms/kg-1 of buprenorphine. A significant difference in heart rate was also observed between the two buprenorphine groups at 5 and 10 min after intubation. Blood pressure and heart rate both showed a significant fall from baseline values 10 min after intubation in both buprenorphine groups, with the changes being greater in the 5 micrograms.kg-1 group. We recommend the use of 2.5 micrograms.kg-1 buprenorphine for attenuation of the hypertensive response to intubation in major abdominal surgery.

Adult↗
PubMed1996

Total spinal anaesthesia following caudal block with bupivacaine and buprenorphine.

This is a case report of an 18-month-old 10 kg child who presented for emergency repair of a recurrent diaphragmatic hernia with a history of craniofacial dystosis and was given a caudal block postoperatively with a combination of 4 ml of 0.5% bupivacaine and 2.5 micrograms.kg-1 buprenorphine made up to a total volume of 10 ml. An inadvertent dural puncture occurred resulting in total spinal block which was managed symptomatically. Block regression started one h later when the respiratory movements became noticeable. Eye opening and hand movements returned 3 h later. The patient's exposure to a large intrathecal dose of buprenorphine did not lead to prolonged respiratory depression. The possibility of a midbrain insult due to a sudden rise in intracranial pressure is also discussed.

Analgesia, Epidural↗
PubMed1996

Activation of hypothalamic neurons by intraovarian pressure signals in a teleost fish, Clarias batrachus: role of mechanosensitive channels.

Application of intraovarian pressure is known to trigger profound cytomorphological changes in the neurosecretory cells of nucleus preopticus in the teleost Clarias batrachus. These findings indicate the presence of stretch receptors in the ovaries, perhaps equipped with mechanosensitive channels that transduce the stretch signals to be transmitted to the brain. To test the occurrence of the mechanosensitive channels in the ovaries, we administered a range of pharmacological agents (lignocaine, quinidine, tetraethylammonium chloride, ethylene-diaminetetraacetic acid and gadolinium) known to block the mechanosensitive ion channels, in the ovarian lumen prior to the administration of the intraovarian pressure. Pretreatment with the above agents inhibited the response by the nucleus preopticus neurosecretory cells to intraovarian pressure. The results suggest the occurrence of the mechanosensitive channels in the ovaries of teleostean fishes. In terms of function we speculate that the stretch sensory system and the ensuing pathway connecting the ovaries with the hypothalamus might play a role in apprising the brain of the status of ovarian maturity and in the initiation of the spawning reflex.

Animals↗
PubMed1996

Complications of endotracheal intubation in mechanically ventilated patients in a general intensive care unit.

During a period of one year, 126 patients were prospectively audited to analyse complications of endotracheal intubation in a general intensive care unit setting. A total of 62 complications were observed in 48 patients. The most frequent complications during intubation were hypotension and bradycardia. The blockage of endotracheal tubes significantly increased with the duration of intubation. Sore throat was the commonest (22%) complication following extubation. Other complications like stridor and ulceration of mouth and lips which followed extubation were not related to the duration of intubation.

Adolescent↗
PubMed1996

Experience with larangeal mask airway in Pakistani patients.

One hundred and thirty seven adult patients undergoing peripheral surgery were studied regarding ease of larangeal mask airway (LMA) insertion, airway maintenance during surgery and complication encountered during insertion, maintenance and in the postoperative period. In a majority (84%) of patients, the airway was positioned correctly at the first attempt, 3% patients had mild laryngospasm at insertion and in 85% a good airway was obtained. No airway related problems were encountered intraoperatively. Two percent patients had laryngospasm on removal of LMA. Postoperatively, the complaint of sore throat and uvular trauma was seen in 4% cases.

Adolescent↗
PubMed1995

Femoral neck fracture: a complication of femoral nailing.

A fracture of the shaft of the femur in adults is common after road traffic accidents. Until recently it was not known that a fracture of the femoral neck can occur while fixing the femoral shaft fracture with an intramedullary nail. We report three patients in whom femoral neck fractures occurred during femoral nailing. Fractures of the femoral neck were detected by routine postoperative radiographs of the hip joint. All the three patients were treated non-operatively and the fractures healed without complication. The cause of the femoral neck fracture seems to be forceful use of an awl in the wrong direction or multiple entry points in the trochanteric region which weaken the femoral neck; subsequent hammering of the nail completes the fracture.

Adult↗
PubMed1995

Effect of general anaesthesia and surgery on neutrophil function.

The effects of general anaesthesia and surgical trauma on neutrophil function were studied in 60 female ASA 1 and 2 patients undergoing anaesthesia for gynaecological surgery. Patients were divided into three groups depending on the degree of trauma and duration of surgery. Group 1 (n = 15) were patients for dilatation and curettage (minor surgical trauma) and were given 2% halothane. Group 2 (n = 30) had laparoscopic surgery (moderate surgical trauma) and received either 0.5% halothane or 1% enflurane. Group 3 (n = 15) were those having hysterectomy (major surgical trauma) and received 0.5% halothane for a longer duration. Venous samples were taken 30 min before anaesthesia (control value), 10 min after induction of anaesthesia, 10 min after the start of surgery, 30 min after the end of anaesthesia and 24 h later. Phagocytic index, nitroblue tetrazolium reduction test, total leucocyte count, and differential leucocyte counts were performed on each sample. Data were analysed by paired t-test to compare findings in the same patient and by unpaired t-test for differences between groups. Anaesthesia with halothane 0.5% to 2% caused a dose-related depressant effect on leucocyte function which reversed. Enflurane 1% on the other hand caused significantly greater depression of leucocyte function compared with 0.5% halothane which persisted during the recovery period and recovered on the first postoperative day. Total leucocyte counts also showed a fivefold increase in the major surgery groups.

Adolescent↗
PubMed1995

Caudal analgesia with buprenorphine for postoperative pain relief in children.

Caudal buprenorphine was investigated as a postoperative analgesic in a randomized double blind study in thirty children aged 5-12 years undergoing lower abdominal and lower limb surgery. Comparison was made between two groups of patients, one group receiving plain bupivacaine and the other a combination of plain bupivacaine with buprenorphine. Postoperative analgesia was assessed using a linear analogue scale, and by the response to direct questioning of children using an illustration of sequence of faces. Any untoward side effects and the need for additional analgesics were recorded. The degree and duration of analgesia was far superior in the buprenorphine group and there was a highly significant difference in the requirement of postoperative analgesia between the two groups. There were no major adverse side effects and no motor weakness in either groups, however the incidence of nausea and vomiting was higher in the buprenorphine group. It is concluded that a combination of bupivacaine with buprenorphine administered through the caudal epidural space is a safe and reliable means of providing postoperative pain relief in children for up to 24 h.

Abdomen↗
PubMed1995

Cytokines affect pseudomonas binding to tracheal cells via a neutrophil-mediated process.

Critical illness is often associated with gram-negative bacterial colonization of the airways, increasing the risk of nosocomial pneumonia. Cytokines, released in response to endotoxin, might contribute to this phenomenon by causing changes in epithelial cell binding of bacteria. To investigate this possibility, human monocytes and hamster pulmonary macrophages were cultured without or with Escherichia coli endotoxin (10 micrograms/ml) for 4 and 24 h. Hamster and human tracheal epithelial cells were treated with supernates from monocyte cultures for 24 h, and subsequent binding of 14C-labeled Pseudomonas aeruginosa to the epithelial cells was measured (percent adherence). In separate experiments, recombinant human (rh) tumor necrosis factor-alpha (TNF-alpha) (25 to 100 ng/ml) and interleukin-1 beta (IL-1 beta) (2,000 to 8,000 pg/ml) were added to hamster monolayers. Neither monocyte supernates nor purified cytokines were toxic to the epithelial cells for up to 48 h. There was no significant change in P. aeruginosa adherence to either hamster or human tracheal epithelial cells after 24 h of exposure to culture supernates from either endotoxin-stimulated human monocytes or hamster macrophages. Similarly, purified rhTNF and rhIL-1 exposure did not increase bacterial adherence. However, when polymorphonuclear leukocytes were coincubated with the monocyte supernates and epithelial cells, P. aeruginosa adherence was significantly increased. Moreover, this effect was enhanced by an epithelial cell-derived substance. Thus, while inflammatory cytokines may participate in enhancing bacterial colonization of the lung in vivo, they do not do so by a direct action on tracheal epithelial cells but can act via a neutrophil-dependent mechanism.

Animals↗
PubMed1995

Myocardial stunning following respiratory arrest.

Myocardial stunning is defined as a prolonged myocardial dysfunction with gradual return of contractile activity after a brief episode of severe ischemia. Usually it is seen in patients with myocardial infarction following treatment with thrombolytic agents, in patients with angina, and in patients recovering from cardiopulmonary bypass surgery. We report an interesting case of myocardial stunning following respiratory arrest.

Adult↗
PubMed1995

Treatment of slipped capital femoral epiphysis with severe displacement (report of 14 hips in 12 non Caucasian patients).

This paper presents a report of a study of 14 hips in 12 non Caucasian patients treated for severe slipped capital femoral epiphysis. There were four Sudanese, two Syrians, and six Libyan patients. Three hips in two patients had severe acute slip and eleven hips in ten patients had severe chronic slip. Patients with severe acute slip were treated by closed reduction and internal fixation. Patients with severe chronic slip were treated by open replacement of the femoral epiphysis using the procedure advocated by Dunn and Angel[1]. One patient treated for acute severe slip developed over reduction of the epiphysis after closed manipulation. The results were good in all the three hips with acute slip. Two hips with severe chronic slip developed avascular necrosis and chondrolysis. Considering the results in this small series, closed reduction and internal fixation is a satisfactory method of treatment for severe acute slip while results of open replacement of the epiphysis for severe chronic slip has high incidence of complication in non caucasian patients as compared to those reported for caucasians.

Acute Disease↗