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Biomedical subjects

A K Sharma

Publications and source records attributed to A K Sharma.

At least 253 records · Page 14Linked to original sources
PubMed1994

Interactions of neuromuscular blocking agents with ethanol.

Alcohol produces contraction of isolated frog rectus abdominis muscle in a dose dependent manner. In the present study interactions of pancuronium, gallamine and succinylcholine with ethanol have been studied. Pancuronium and gallamine behaved in a non-competitive manner with ethanol. The PD'2 values of pancuronium and gallamine were almost similar. Succinylcholine produced persistent contraction of the muscle which remained unaltered on addition of ethanol. The findings with pancuronium and gallamine suggest that ethanol may be acting through metactoid nicotinic receptors or by the release of acetylcholine like substance.

Animals↗
PubMed1994

Effect of vitamin A excess on oral armature in tadpoles of toad, Bufo melanostictus (Schneider) and frog, Rana cyanophlyctis (Schneider).

Tadpoles of B. melanostictus and R. cyanophlyctis were reared in vitamin A solution. Rearing of the tadpoles of B. melanostictus in solutions containing 15, 20 and 30 IU/ml vitamin A palmitate resulted in complete disappearance of the keratinized epidermal material over the jaws and horny labial teeth. However tadpoles of the frog R. cyanophlyctis, were not affected in this way.

Animals↗
PubMed1994

Effect of group substitution on the physicochemical properties of ibuprofen prodrugs.

A series of alkyl ester prodrugs of ibuprofen was synthesized and studied for its physicochemical properties like aqueous solubility, octanol-water partition coefficient and hydrolysis kinetics in aqueous buffer and human plasma. These physicochemical parameters have a forebearing on the overall activity profile of these prodrugs. Mathematical relationships have been derived to characterize these properties.

Chemical Phenomena↗
PubMed1994

Hyperlipidemia in long-term survivors of pediatric renal transplantation.

The prevalence of hyperlipidemia in adolescents and young adults who are long-term survivors of pediatric renal transplantation with stable graft function has not previously been examined. We studied 33 renal transplant recipients aged 5 to 23 years, who were an average of 7.4 years (range 3 to 11 years) post-transplant. We found hypercholesterolemia in 17 (total cholesterol (TC) > 5.18 mmol/l). Both low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) levels were increased, such that the mean TC/HDL-C and apolipoprotein B/apolipoprotein A1 (Apo B/Apo A1) ratios were below levels associated with increased coronary artery disease risk. Subjects with hypercholesterolemia did not differ from those with normal cholesterol values in current age or age at transplant, serum creatinine, serum albumin, serum triglycerides, HDL-C, TC/HDL-C ratio, Apo B/Apo A1 ratio, prednisone dose, body mass index, gender, use of thiazides or beta blockers, or family history of premature atherosclerosis. Coronary risk factors appear to cluster in these patients, with hypertension in 53% of those with hypercholesterolemia. Lipid profiles were not different in patients treated with prednisone-azathioprine vs. prednisone-azathioprine-cyclosporine A immunosuppression. A significant correlation was found between prednisone dose (mg/m2) and TC, LDL-C and TC/HDL-C. According to National Cholesterol Education Program guidelines, 32% of these long-term survivors of pediatric renal transplantation warrant at least dietary intervention and 10% are candidates for treatment with lipid-lowering drugs. This proportion is likely to increase as the safety of lipid-lowering agents is established in younger children.

Adolescent↗
PubMed1994

On mechanism of action of ethanol-induced contraction of frog rectus abdominis.

Ethanol in low doses (0.5 to 4 M) causes contraction of isolated frog rectus abdominis muscle. Higher concentration did not produce any further increase in maximum response. Pretreatment with dantrolene produced partial but equal inhibition of acetylcholine (Ach) induced as well as ethanol-induced contraction in equieffective doses. Pretreatment with pancuronium produced right and downward shift of ethanol induced contraction. Pretreatment with succinylcholine produced persistent contraction of tissue and this response remained unaffected on subsequent treatment with Ach as well as ethanol. Pretreatment with hemicholinium abolished ethanol induced contraction, although tissue remained viable as confirmed on addition of Ach. The contraction induced by ethanol decreased on pretreatment with dantrolene as well as in Ca2+ free ringer. The results indicate that ethanol induced contraction may be due to release of Ach or Ach like neurotransmitter at neuromuscular junction and calcium acts as mediator to produce these effects.

Acetylcholine↗
PubMed1993

Localization of adjacent binding domains for cellular proteins over the minute virus of mice P4 promoter by site-specific photoaffinity labelling.

A photoaffinity labelling (PHL) procedure was used to localize the specific binding sites for A92L fibroblast nuclear proteins on the minute virus of mice (MVM) P4 promoter. We describe a chemical and biochemical method for the construction of precisely modified photoreactive (phr) DNA probes. In this method, a phenylazide group is attached to the DNA fragment by coupling SASD [sulfosuccinimidyl-2-(p-azidosalicyl-amido)ethyl-1,3'-dithiopro pio nate] to the primary amino group of the linker arm present at any predetermined position. These phr probes would identify, upon photocrosslinking, only those proteins which bind to the location of the phr group. Specifically, two phr probes representing the 139-172 bp region of the MVM P4 promoter were constructed in which the highly phr phenylazide group was attached with a linker at nucleotide 168, towards the side of the GC box proximal to the TATA box. The PHL studies with these photoprobes revealed that although the proteins of 95 and 120-kDa bind near nt 168 of the P4 promoter, the 120-kDa protein requires the region between the TATA box and the GC box for binding to the MVM P4 promoter.

Affinity Labels↗
PubMed1993

Endoneurial localisation of microvascular damage in human diabetic neuropathy.

Twenty diabetic patients with neuropathy underwent clinical and neurophysiological evaluation together with a detailed morphometric assessment of capillary pathology in endoneurial and epineurial microvascular beds of the sural nerve. Morphological data were compared with ten non-diabetic control subjects. There were no significant differences in control subjects between basement membrane area, endothelial cell area, endothelial cell profile number or luminal area of endoneurial when compared with epineurial capillaries. In contrast, when compared with epineurial capillaries, endoneurial capillaries from diabetic patients demonstrated a significant increase in basement membrane (p < 0.001) and endothelial cell (p < 0.001) area and a significant reduction in luminal area (p < 0.001). There was no significant difference in endothelial cell profile number between endoneurial and epineurial capillaries amongst diabetic patients. Previous studies have demonstrated a good correlation between the degree of microangiopathy and measures of neuropathic severity. In the present study increased endoneurial capillary basement membrane area was significantly related to reduced peroneal nerve conduction velocity (p < 0.001), myelinated fibre density (p < 0.001) and elevated vibration (p < 0.05) and thermal (p < 0.001) perception. Increased endothelial cell area and reduced luminal size were related to a reduced peroneal nerve conduction (p < 0.05, p < 0.01, respectively), reduced myelinated fibre density (p < 0.05, p < 0.01) and elevated thermal perception (p < 0.05, p < 0.001). Epineurial capillary basement membrane, endothelial cell and luminal area failed to relate to measures of neuropathic severity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

The management of end-stage renal disease in infants with imperforate anus.

Genitourinary malformations are frequently associated with imperforate anus, and death from renal failure is reported in up to 6% of children with supralevator imperforate anus. In recent years, advances in renal transplantation and the management of end-stage renal disease (ESRD) have extended these therapies to infants in the first 2 years of life. In infants with imperforate anus and ESRD, it is unclear if the additional burdens of the anorectal malformation and its staged repair contraindicate dialysis and transplantation. This report describes our experience with three such infants and outlines an approach to their care, addressing the following key issues: the initial surgical management of the imperforate anus, the careful search for associated urinary tract and other malformations, the ESRD management, and the appropriate timing of the staged bowel reconstruction and renal transplantation. These cases confirm that such children may be successfully managed by dialysis and renal transplantation co-ordinated with bowel reconstruction; however, there remain the long-term risks of immunosuppression, bladder and bowel dysfunction, and associated congenital anomalies.

Anus, Imperforate↗
PubMed1993

Interstitial fibrosis in obstructive nephropathy.

Interstitial fibrosis and tubular basement membrane (TBM) thickening are evident within 16 days of unilateral ureteral obstruction (UUO) in the rabbit, and resemble the changes previously reported in hydronephrotic human kidneys. The cortical interstitial volume fraction in this rabbit model at 16 days is 43.3 +/- 6.1% (+/- 1 SD) in UUO kidneys, 4.9 +/- 3.1% in contralateral kidneys (CLK), and 2.8 +/- 0.8% in kidneys from sham-operated animals (ANOVA, P < 0.0001). Immunohistochemically, UUO is associated with increased interstitial collagens I and III, fibronectin, heparan sulfate proteoglycan and tubulointerstitial nephritis antigen. Aberrant collagen expression is also evident as interstitial collagen IV becomes prominent. Focal, peritubular accumulation of collagens I and II also appear to encircle the TBM. These changes are accompanied by an early, transient increase in renal cortical mRNA encoding the alpha 1 monomers of collagens I, III and IV, implicating increased matrix synthesis in the pathogenesis of obstructive nephropathy. In situ hybridization localized increased expression of alpha 1 (I) and alpha 1 (IV) mRNA to cells in the interstitial space, with clusters of alpha 1(I) positive cells associated with dilated tubules, muscular arteries and the periglomerular interstitium.

Animals↗
PubMed1993

Combined multidrug and Mycobacterium w vaccine therapy in patients with multibacillary leprosy.

Immunotherapy with Mycobacterium w vaccine was attempted in patients with borderline-borderline, borderline lepromatous (BL), or lepromatous leprosy (LL) to determine whether immunization can hasten recovery and reduce treatment time by invigorating cell-mediated immunity. Mycobacterium w, a nonpathogenic, rapidly growing, atypical mycobacterium, shares a number of common B and T cell determinants with Mycobacterium leprae and Mycobacterium tuberculosis. Patients receiving the vaccine had rapid clinical improvement and accelerated bacteriologic clearance. After treatment with vaccine for 2 years, 13 of 31 BL and LL patients were bacteriologically negative as were 5 of 25 controls. Vaccinated patients had one of two distinct histologic features, either an upgrading in the disease spectrum or complete clearance of granuloma. Some 80% of lepromin conversions were in BL and LL patients who received vaccine versus none and 14.3% of BL and LL controls, respectively. Thirteen of 17 vaccinated LL patients were released from treatment after 2 years in contrast to 2 of 15 controls.

Bacterial Vaccines↗
PubMed1993

Tuberculosis of the thyroid gland: a clinicopathological profile of four cases and review of the literature.

Four cases of tuberculosis of the thyroid with different presentations including chronic sinus (following drainage of thyroid abscess), thyrotoxicosis, severe dysphagia clinically mimicking malignancy and euthyroid multinodular goitre are described. Except in the case presenting with chronic sinus (discharging acid-fast bacilli), the diagnosis was a pathological surprise (cytopathology in one and histopathology in two). Only in one case was there evidence of disease outside the cervical region. All cases showed multiple coalescing and caseating epitheloid cell granulomas along with giant cells, which are considered as diagnostic of tuberculous thyroiditis even if acid fast bacilli cannot be demonstrated. The literature is reviewed and the pathogenesis discussed.

Adult↗
PubMed1993

Tubercular mastitis: a pragmatic approach to its management.

Six cases of tubercular granulomatous mastitis were studied retrospectively. Three of these six cases posed diagnostic difficulties because of a lack of caseation in granuloma on fine needle aspiration cytology. A pragmatic approach is described here that is based on the correlation of the clinical features with the cytological findings. All six cases improved on therapeutic trial of antitubercular treatment.

Adolescent↗
PubMed1993

Reversal reaction in multibacillary leprosy patients following MDT with and without immunotherapy with a candidate for an antileprosy vaccine, Mycobacterium w.

Immunotherapy with a candidate for an antileprosy vaccine, Mycobacterium w, was given in addition to standard multidrug therapy (MDT) to 53 multibacillary lepromin negative patients belonging to BB, BL and LL types of leprosy (vaccine group). An equal control group received MDT and injections of micronized starch as placebo. Both the vaccine and placebo were administered intradermally every 3 months. The patients were evaluated at determined intervals by clinical, bacteriological and histopathological parameters and lepromin testing. Reactional episodes were analysed with reference to incidence, onset, frequency and severity during and after release from treatment (RFT). Incidence of reversal reaction (RR) was marginally higher in the vaccine group (22.6% vaccine group vs 15% control group). All cases with a history of downgrading type 1 reaction developed RR during therapy. Most episodes occurred within the 1st year of the commencement of therapy--50% developing within 3 months. Late reversal reaction (after RFT) were observed in 3.8% of cases in both groups, and 50% of the reactors in the control group and 33% in the vaccine group had repeated reactional episodes. Incidence of neuritis associated with RR as well as isolated neuritis was similar in both groups.

Bacterial Vaccines↗