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Biomedical subjects

B Singh

Publications and source records attributed to B Singh.

At least 433 records · Page 24Linked to original sources
PubMed1995

Trace element distribution in rat brain following lead and lithium supplementation--a study using an EDXRF spectrometer.

Distribution of K, Fe, Cu, Zn, Br and Rb in whole brain samples following combined Pb and Li administration to female Porton rats has been investigated by using the Energy Dispersive x-Ray Fluorescence (EDXRF) technique. Brain K, Cu and Rb levels are diminished, whereas Fe and Br levels are enhanced significantly following short-term (1 month) and long-term (4 months) combined treatment with Li (1.1 g/kg diet) and two doses of Pb (50 and 100 mg/kg body weight). The Zn levels are lowered following combined treatment with Li and both the doses of Pb given for short-term only.

Animals↗
PubMed1995

The management of sinogenic orbital complications.

The place of conservative treatment in sinogenic orbital complications has not been fully explained in the literature. The question that remains unresolved is--at which stage of the disease is surgery indicated? A study was undertaken in 240 patients with sinogenic orbital complications, to determine this. The patients were divided into three groups according to the stage of the disease as determined clinically: Group 1 (52 patients) with early stage disease, as detected by cellulitis only; Group 2 (76 patients) with intermediate stage, as detected by periorbital cellulitis and proptosis, but with full range of eye movement and unaltered vision; Group 3 (122 patients) with late stage disease, as detected by periorbital cellulitis and gross proptosis, with limitation of eye movement and altered vision. Group 1 and Group 2 patients were treated conservatively, with intravenous antibiotics and antral lavage. Group 3 patients were treated with intravenous antibiotics and surgery. External frontoethmoidectomy was performed in 31 (bilateral in two), ethmoidectomy in 91 (bilateral in five), sphenoidectomy in 15 and bilateral antral washout in all (122 patients). There was 100 per cent success with conservative treatment in Group 1 patients, whilst in Group 2 there was 98.6 per cent failure. The 75 patients in whom conservative treatment failed were successfully treated with surgery: frontoethmoidectomy was performed in 66 and ethmoidectomy in nine. In Group 3 patients, 100 per cent success was achieved with intravenous antibiotics and surgery. Sinogenic orbital complications can be treated conservatively and surgically, depending on the stage of the disease on presentation. Conservative treatment is only suitable for early complications, i.e. patients with periorbital cellulitis only.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Schwannoma of the posterior pharyngeal wall.

Schwannoma of the posterior pharyngeal wall, in a 36-year-old male patient is presented demonstrating the asymptomatic nature of the tumour (which is peculiar to schwannomas). The tumour gradually increased in size, destroyed the body of the third cervical vertebra but remained asymptomatic. The patient only presented to hospital when the tumour obstructed the airway, because of its large size.

Adult↗
PubMed1995

Sinogenic intracranial complications.

Two hundred and nineteen patients, with intracranial complications of sinusitis, are presented. Sinusitis is still a life-threatening condition and if neglected, or mismanaged, can lead to intracranial complications that result in a high mortality and morbidity. Twenty-two patients had meningitis, 127 subdural empyema, 38 brain abscess, 15 combined brain abscess and subdural empyema and 17 extradural empyema. The diagnosis of intracranial abscess and sinusitis was made with the aid of a CT scan, and that of meningitis on cerebrospinal fluid microscopy, chemistry and culture. The most frequent presenting signs were fever (68 per cent) and headache (54 per cent). The most common localizing neurological sign was hemiparesis (35.5 per cent). Orbital inflammation was present in 41.5 per cent of patients. Treatment entailed immediate, appropriate, intravenous antibiotic therapy and prompt surgery, performed within 12 hours of admission. In patients with meningitis, the surgery entailed surgery of the sinus disease only. In patients with subdural empyema, brain abscess and extradural empyema, evacuation of the primary source of infection by the radical frontoethmoidectomy approach, immediately after drainage of the intracranial collection of pus, was carried out. There were 35 deaths (16 per cent). The highest mortality rate was recorded in patients with meningitis (45 per cent) followed by brain abscess (19 per cent) and subdural empyema (11 per cent). Despite advances in medicine, i.e. antibiotics and CT scan for early and accurate diagnosis, the mortality from sinogenic intracranial complications has remained significant. This can only be eliminated through education.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Transforming growth factor alpha gene expression and peptide localization in porcine ovarian follicles.

The present study was undertaken to determine transforming growth factor alpha (TGF alpha) gene expression in various components of medium-sized porcine ovarian follicles by reverse transcription-polymerase chain reaction, and to localize the peptide during folliculogenesis by immunocytochemistry. A strong signal for TGF alpha transcript was detected in cumulus and granulosa cells, whereas the signal in theca cells was very weak but detectable. No TGF alpha mRNA was detected in the oocyte. Immunolocalization studies revealed intense TGF alpha staining in cumulus and granulosa cells of all stages of follicular development. TGF alpha immunostaining was also observed in the oocytes of primordial and primary follicles. In antral follicles, immunostaining was observed only in cumulus and mural granulosa cells, whereas theca cells and oocytes exhibited very little or no detectable staining. TGF alpha immunostaining was absent in follicles undergoing atresia. No TGF alpha immunostaining was observed when the antibody was omitted from the procedure, and the staining was substantially reduced when the primary antibody was preabsorbed with the same mass of TGF alpha peptide, suggesting the specificity of the staining procedure. These results suggest a local follicular production of TGF alpha in the porcine ovary and thus a role for TGF alpha of follicular origin in the regulation of follicular development in an autocrine/paracrine fashion.

Animals↗
PubMed1995

Species-dependent pharmacodynamic effects of the selective low Km cyclic AMP phosphodiesterase III inhibitors WIN 58993 and WIN 62005.

We describe the biochemical and pharmacologic effects of two novel fused pyridinones derived from milrinone: WIN 58993 and WIN 62005. Both WIN 58993 and WIN 62005 competitively inhibit cyclic GMP-inhibitable low Km cyclic AMP phosphodiesterase (PDE III) from rat heart and canine aorta with Ki values of 25 +/- 3 and 26 +/- 5 nM, respectively, and are selective (at least 160-fold) for PDE III inhibition relative to other PDE isozymes. WIN 58993 and WIN 62005 were given to conscious, chronically instrumented rats and dogs intravenously (i.v.) or perorally (p.o.). Because the doses of WIN 58993 and WIN 62005 required to decrease mean arterial blood pressure (MAP) by 20% were estimated to be 0.9 and 0.7 mg/kg, respectively, the compounds appear to be equipotent after acute i.v. administration in rats. However, the duration of the depressor responses in rats apparently differs since MAP remained significantly decreased 6 h after i.v. or p.o. administration of WIN 58993, but returned to control levels < or = 4 h after administration of WIN 62005. WIN 58993 may be slightly less potent than WIN 62005 after acute i.v. administration to dogs since significant increases in left ventricular (LV)dP/dtmax first occurred at doses of 0.1 and 0.03 mg/kg, respectively. LVdP/dtmax significantly increased in 30 min and returned to baseline 3 h after p.o. administration of 1 mg/kg WIN 58993. After p.o. administration of 1 mg/kg WIN 62005. LVdP/dtmax was significantly increased in 30 min and remained increased for at least 6 h. These data suggest that WIN 58993 and WIN 62005 are potent, selective, p.o.-active inhibitors of PDE III.(ABSTRACT TRUNCATED AT 250 WORDS)

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1995

Dynamic assessment of the electrocardiographic QT interval during citrate infusion in healthy volunteers.

OBJECTIVE: To investigate changes in the electrocardiographic QT interval during rapidly induced, sustained hypocalcaemia in healthy volunteers. DESIGN: Serial rate corrected QT measurements were made during and after a variable rate trisodium citrate infusion designed to "clamp" the whole blood ionised calcium concentration 0.20 mmol/l below baseline for 120 min. SUBJECTS: 12 healthy teetotallers aged 19- 36 years who were not receiving medication known to influence calcium homoeostasis. MAIN OUTCOME MEASURES: Whole blood ionised calcium concentration and QaTc intervals (onset of the Q wave to T wave apex divided by the square root of the RR interval). RESULTS: Mean (SD) ionised calcium concentration decreased from 1.18 (0.03) mmol/l preinfusion to values close to target (0.98 mmol/l) between 10 and 120 min. The QaTc interval lengthened from a baseline of 0.309 (0.021) to a maximum 0.343 (0.024) s0.5 at 10 min before returning to a stable level from 15 to 120 min (0.334 (0.023) and 0.330 (0.023) s0.5 respectively). The change from baseline of both variables expressed as a ratio (delta QaTc/ delta [Ca2+]) was greater during rapid induction of hypocalcaemia (at 5 and 10 min) than at other times during and after the infusion (P < 0.02). CONCLUSIONS: The disproportionate prolongation of QaTc interval during prompt induction of hypocalcaemia suggests rate dependency which can be represented by a hysteresis relation between (ionised calcium, QaTc) coordinates. This finding may have clinical implications.

Adult↗