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Biomedical subjects

R Gandhi

Publications and source records attributed to R Gandhi.

52 records · Page 3Linked to original sources
PubMed1989

Use of urinary enzymes as markers of nephrotoxicity.

Urinary excretion of enzymes can be monitored continuously at low cost, with commonly available laboratory equipment; there is little discomfort for the animal or person investigated. Under controlled conditions, the time-course and dose-dependence of some pathophysiological events in the kidney can be followed by measuring urinary enzymes. The activities of enzymes in urine are, however, affected by a large number of parameters, even under physiological conditions. Furthermore, the heterogeneity of the kidney renders application of urinary enzymes for diagnostic purposes difficult. Assessment of renal injury by urinary analysis may be possible only if the pathophysiological mechanisms and the time sequence of the nephrotoxicity are known.

Biomarkers↗
PubMed1989

Purification and properties of a 5'-nucleotidase from rat renal membranes.

5'-Nucleotidase activity was solubilized from a particulate fraction of rat renal homogenates by Sulphobetaine 14. An 11,430-fold purification was achieved by a two-step chromatographic procedure using concanavalin-A Sepharose and ADP-agarose. SDS-PAGE of the purified material revealed a single polypeptide band with a Mr of 69,000. The enyzme exhibited absolute specificity for 5'-mononucleotides. Among 7 tested substrates, adenosine monophosphate (AMP) showed the highest value of V/Km. The Km for 5'-AMP is 5.1 mumol/l and V is 632 mumol/min/mg. The plot of activity versus pH shows a broad plateau between pH 6.8 and 8.0. The hydrolysis of 5'-AMP was competitively inhibited by adenosine 5'-triphosphate (ATP; Ki = 1.2 mumol/l), adenosine 5'-diphosphate (ADP; Ki = 0.032 mumol/l) and alpha, beta-methyleneadenosine 5'-diphosphate (AOPCP; Ki = 0.005 mumol/l). All of the 5 detergents tested activated the enzyme. Sulphobetaine 14 was the most potent and resulted in a 4-fold stimulation by increasing V without change of Km. Addition of exogenous divalent cations was not required for activity. However, the enzyme was inhibited by EDTA. This inhibition was overcome by the addition of Co2+, Mn2+ and to a lesser extent of Mg2+. Hg2+, Zn2+, Cu2+ and Pb2+ inhibited in the low micromolar range. The properties of this enzyme from the rat kidney are similar to those reported in the literature for ecto 5'-nucleotidases from other sources.

5'-Nucleotidase↗
PubMed1989

Ecto-5'-nucleotidase: localization in rat kidney by light microscopic histochemical and immunohistochemical methods.

We demonstrated the distribution pattern of ecto-5'-nucleotidase (5'-Nu) in rat kidney by enzymatic activity (lead salt precipitation) and by immunohistochemistry with a polyclonal antibody raised in rabbits. Enzyme activity was found in the brush border of the proximal tubule, highest in the P1 segments with decreasing intensity in the P2 segments and weakest in P3 segments in the medullary rays of the cortex. The P3 segments of the outer stripe showed slightly higher activity. Activity was also apparent in the intercalated cells in the connecting tubule and collecting duct, whereas all other tubular and glomerular structures were negative. Activity in peritubular and perivascular connective tissue was highest in the cortical labyrinth, weak or absent in the medullary rays of the cortex, and entirely absent in the medulla. The distribution of the antigen was fully congruent with that of the enzyme activity. With respect to the role of adenosine in regulation of renal blood flow and glomerular filtration rate, the distribution of 5'-Nu in the cortical interstitium may be particularly significant. The possibility of nucleotide cleavage at the brush-border membranes may be important for salvage of nucleotides from the tubular lumen.

5'-Nucleotidase↗
PubMed1987

Fifteen years' experience with penetrating trauma to the head and neck in children.

To determine the extent and consequences of penetrating trauma to the head and neck in children, as well as the safety and efficacy of selective management of penetrating wounds of the face and neck, we reviewed our experience with these injuries since 1970. During this interval, 45 children aged 2 to 17 years were admitted for treatment of 37 missile wounds (MW) and eight stab wounds (SW). Most patients reached the hospital within 30 minutes of injury. The greatest single number of these injuries were due to accidents; violent crimes accounted for the remainder of injuries in which a motive for attack was known. Craniotomy was performed in neurologically viable patients only; neck exploration was reserved for those patients who presented with profuse hemorrhage, an expanding or pulsatile hematoma, respiratory distress, or violation of the esophagus, trachea, or great vessels seen on fluoroscopy, endoscopy, or angiography. Overall survival was 87% (MW 84%, SW 100%). Three of the nonsurvivors presented in extremis with gunshot (GSW) wounds to the head, and died shortly thereafter, while two who presented with similar injuries survived craniotomy but died subsequently from irreversible brain damage; one presented in shock due to massive hemorrhage (internal jugular vein transection flush with the base of the skull) and exsanguinated during attempted repair. Among the 39 survivors, 15 sustained multiple wounds, but only two presented in shock, due in both instances to tension pneumothorax. Soft tissue injuries of the scalp, face, and neck accounted for 36 of the 39 nonfatal wounds; five of these involved major cervical structures, but only four required immediate exploration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

External silo reduction of the unruptured giant omphalocele.

Construction of an external silo dressing over the intact omphalocele membrane allows complete reduction of the giant omphalocele with enlargement of the abdominal cavity before surgical intervention, so that primary closure of the abdominal wall can be achieved. Three infants with giant omphalocele containing a central liver were successfully managed by this technique avoiding the complications associated with operative silo placement or simple membrane painting.

Bandages↗
PubMed1987

Response to injury in children with closed femur fractures.

Fifty children admitted with closed femur fracture as a single major injury were monitored for change in vital signs and hematocrit. Hypotension was not observed. No child required blood replacement. Only 33% of the children had a measurable change in hematocrit, averaging a four-point drop. There was a marked febrile response to injury in 80% of the children which lasted an average of 4 days. Children admitted with femur fractures who develop hypotension or rapid drop in hematocrit should be promptly evaluated for another source of blood loss.

Adolescent↗
PubMed1986

Effect of recombinant interferon-gamma on hydrogen peroxide-releasing capacity of monocyte-derived macrophages from patients with lepromatous leprosy.

Monocyte-derived macrophages from 14 patients with lepromatous leprosy respond to rIFN-gamma with an enhanced secretion of H2O2 in a fashion similar to that of cells obtained from normal donors. The activation is not dependent on the cutaneous bacterial index, the length of treatment, or the stage and activity of the disease. H2O2 release can be triggered in these cells both by phorbol myristate acetate and by intact irradiated Mycobacterium leprae. Uptake of M. leprae by both normal donors' and patients' macrophages is proportional to the number of bacilli added. Prior ingestion of M. leprae does not interfere with the ability of macrophages to respond to IFN-gamma by the production of oxygen intermediates. We conclude that the immune defect in lepromatous leprosy probably results from a lack of response to M. leprae by the patients' T cells rather than an inability of mononuclear phagocytes to respond to IFN-gamma.

Adolescent↗
PubMed1986

Single-dose pharmacokinetics of oral ciprofloxacin in patients with cystic fibrosis.

The single-dose pharmacokinetics of oral ciprofloxacin were studied in ten patients with cystic fibrosis aged 18 to 34 years. Each patient received three different drug doses (500 mg, 750 mg, and 1,000 mg) at successive one-week intervals. Dosing and drug assays were double blinded. Blood and urine were assayed over the 48 hours following each dose. Ciprofloxacin was absorbed from the gastrointestinal tract. Peak serum concentrations averaged 2.8, 4.5, and 4.6 micrograms/mL respectively at the three doses, well above the mean inhibitory concentrations of most isolates of Pseudomonas aeruginosa. Time to peak concentration was approximately two hours. The range of sputum levels in three patients was 1.1-2.1 micrograms/mL at four hours after the three doses. The serum elimination half-life was 3.7 hours and was independent of dose. Urinary recovery was 26%; greater than 90% of urinary excretion occurred within the first 12 hours. The results of this study indicate that ciprofloxacin has potential for use in the treatment of P aeruginosa infections in patients with cystic fibrosis.

Administration, Oral↗
PubMed1980

Renal artery thrombosis following blunt trauma.

Renal artery thrombosis after blunt trauma presented without other injury, without external signs of trauma, and without hematuria in the case reported. Review of 65 cases from the literature showed that flank and epigastric pain and proteinuria are usually present. Renal artery thrombosis following blunt trauma has usually been diagnosed too late to salvage the kidney. Nephrectomy is performed for ileus, fever, and pain caused by the necrotic kidney, or for hypertension. Ideally, rapid diagnosis by intravenous pyelogram and arteriography and early surgical intervention should allow revascularization and renal salvage before permanent parenchymal damage has occurred. The cases reviewed showed that successful revascularization without hypertension could be achieved 12 hours after injury. Patent small collateral vessels as well as incomplete or gradual renal artery occlusion may prolong renal salvage time.

Adolescent↗
PubMedDate not supplied

Alkylation of tryptophan during deprotection of Tmob-protected carboxamide side chains.

Alkylation of tryptophan occurred during the synthesis of a 19-amino acid peptide of the following sequence: Tyr Ala Ala Gln Asn Arg Arg Gly Leu Asp Leu Leu Phe Trp Glu Gln Gly Gly Leu. Alkylation was found to occur during cleavage of the peptide from the solid support under acidic conditions in the presence of Tmob, which is used for protecting glutamine and asparagine. Presence of alkylated tryptophan was confirmed by mass spectrometry, HPLC and amino acid sequence analyses.

Alkylation↗