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Biomedical subjects

S K Gupta

Publications and source records attributed to S K Gupta.

At least 523 records · Page 29Linked to original sources
PubMed1991

A ten-year experience with one hundred fifty failing or threatened vein and polytetrafluoroethylene arterial bypass grafts.

Between Jan. 1, 1980, and Dec. 31, 1989, 2187 infrainguinal revascularization procedures were performed. In 130 of these cases with patent bypasses, hemodynamic deterioration was suspected, and urgent arteriography was performed. Twenty additional patients with aortofemoral, femorofemoral, or axillofemoral bypasses demonstrated hemodynamic deterioration. In 93% of failing grafts the condition was suspected because of recurrent symptoms or changes in the pulse examination. Two hundred eighty-five high-grade stenotic or occlusive lesions were identified in inflow arteries, outflow arteries, within the graft, or at proximal or distal anastomoses associated with these 150 grafts. One hundred sixty-one (57%) of these lesions were in patients with failing vein grafts; 115 (40%) were in patients with failing polytetrafluoroethylene (PTFE) grafts; and 9 (3%) were associated with failing composite vein/PTFE grafts. Stenotic lesions less than 5 cm in length were initially treated with percutaneous transluminal balloon angioplasty (PTA). Occlusive lesions, stenoses greater than 5 cm in length, and PTA failures were treated surgically. The overall 6-year cumulative secondary patency rate for failing grafts was 65%, and the limb salvage rate was 75%. The extended patency rate after the first intervention in the failing state was 56% at 5 years. The 5-year secondary patency rate for grafts initially treated with PTA (58%) was not significantly different (p = 0.25) from that for grafts treated initially with surgery (71%). Percutaneous transluminal angioplasty was effective for inflow stenoses of the iliac, femoral, and popliteal arteries and for some outflow lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1991

Topical norfloxacin therapy in Pseudomonas corneal ulceration.

We treated 12 eyes with Pseudomonas ulcerative keratitis with topical 0.3% Norfloxacin drops (Ranbaxy Laboratories). Excellent response was achieved in all eyes, resulting in complete ulcer resolution. The healing time varied from 12 to 20 days. There was a marked improvement over the pretreatment visual acuity in 11 of the 12 eyes. No systemic or ocular side effects were observed during the study period. The present study strongly suggests that topical norfloxacin is a potent and effective drug in the treatment of Pseudomonas ulcerative keratitis.

Administration, Topical↗
PubMed1991

Levels of proteolipid protein mRNAs in peripheral nerve are not under stringent axonal control.

The proteolipid protein (PLP) is the major protein in the myelin sheath of the CNS. It was recently reported that PLP coding transcripts are also found in the PNS, although the protein was not detectable in peripheral nerve myelin. In the present investigation, levels of mRNA for PLP in sciatic nerve were studied during development and following transection and crush injury. Results were compared to those for P0, the major PNS myelin protein, and the myelin-associated glycoprotein (MAG). PLP transcript levels were very low at 21 days in sciatic nerve and remained unchanged in the adult sciatic nerve. This contrasts markedly with P0 and MAG mRNAs, which are expressed at high levels during development and decrease in content significantly by adulthood. The level of PLP messages was reduced approximately 40% in the quiescent Schwann cells in the distal segment of the sciatic nerve at 21 days after permanent transection, yet P0 mRNA levels were very low, and MAG mRNAs were undetectable in this tissue. The distal segment of the crush-injured sciatic nerve is characterized by transient demyelination followed by rapid myelination. PLP mRNA levels remained comparatively unaffected in the 3-week period following crush injury. RNase protection experiments using two antisense riboprobes confirmed that levels of PLP-derived protected fragments, corresponding to PLP and DM-20 messages, remained unchanged in the developing and adult sciatic nerve. These results indicate that myelin-specific P0 and MAG genes are tightly controlled at the level of transcription through Schwann cell-axonal interactions, whereas PLP transcription in the peripheral nerve remains nearly dissociated from axonal influences.

Animals↗
PubMed1991

Mesangiocapillary glomerulonephritis in Down's syndrome.

The clinical and pathologic features of progressive renal disease in 4 patients with Down's syndrome are described. All patients were male, between 20 and 30 years of age at the time of clinical presentation. Three out of 4 had proteinuria, and 2 had hematuria. Serologic tests for hepatitis B virus infection and antinuclear antibodies performed in 2 patients were negative. Examination of renal tissue from biopsy and/or from autopsy revealed mesangiocapillary glomerulonephritis (MCGN), type 1. While an increased incidence of congenital heart disease and acute leukemias has been documented in Down's syndrome, an association with MCGN has not been reported previously to our knowledge. This probably represents a form of idiopathic MCGN and may be related to the long survival of these individuals.

Adult↗
PubMed1991

Cardiac-locomotor coupling while finger tapping: Part II. A cross-over control study.

Cardiac-locomotor coupling (CLC) has been reported by us while people finger tap at cadences natural to them. Since then, we have developed a simple cross-over control strategy in which the heart rate of one subject is related to the finger-tapping rate of another. Of the 20 normal subjects previously studied while tapping a telegraph key at a comfortable rate for 10 min., reevaluation of their data showed that 9 (45%) and 4 (20%) of them, under test and control conditions, respectively, appeared to couple at a single-digit integer ratio. Neither the incidence nor the intensity of apparent CLC under the two conditions was significantly different. Raster plots of the most tightly related rates gave no evidence of phase locking. These results have two implications. First, previously published reports on CLC (and other entrainment phenomena) should be interpreted with caution, and cross-over controls should be considered in future research. Second, the absence of CLC during finger tapping suggests that CLC may only be functionally significant during exercise of large muscle groups (e.g., by minimization of cardiac afterload) or when impact-loading occurs (e.g., by enhancing cardiac ventricular emptying.

Arousal↗
PubMed1991

Preliminary studies on the indium slide immunoassay for estimation of human chorionic gonadotropin and antihuman chorionic gonadotropin antibody.

Human chorionic gonadotropin (hCG) is synthesized and secreted as early as 170 hr after fertilization and has been used as an index for pregnancy. Neutralization of hCG with a beta-subunit hCG vaccine(s) has been proposed as a contraceptive technique. To monitor the duration of effectiveness of the vaccine, it will be necessary to monitor the anti-hCG antibodies, especially those responsible for inhibiting the hCG bioactivity. We report a simple, rapid technique using an indium slide immunoassay for the qualitative estimation of hCG and to monitor a bioeffective anti-hCG antibody. The sensitivity of the indium slide assay to measure hCG ranged from 1 microgram/ml to 1 ng/ml, depending on the format of the assay. The indium slide assay also detected anti-hCG antibodies generated against a specific determinant on hCG recognized by a neutralizing monoclonal antibody (P3W80) in women immunized with a contraceptive vaccine.

Antibodies↗
PubMed1991

Study of cell mediated immunity in chronic tonsillitis.

The cell mediated immune status (CMI) of twenty three patients with chronic tonsillitis was studied with a view to ascertain any possible role of CMI deficiency in causation of the disease. No evidence of significant CMI deficiency was detected in these cases.

Chronic Disease↗
PubMed1991

Urethro-venous intravasation during retrograde urethrography (report of 5 cases).

Five instances of urethro-venous intravasation during retrograde urethrography are reported. Four cases were of urethral strictures and one case was of urethral hemangioma. All patients had post procedural bleeding while one patient got allergic reactions, another showed chills and rigors. Anatomy of the drainage veins is described. Factors responsible for this complication and its clinical implications are discussed. It is suggested that urethro-venous intravasation should be considered a diagnostic sign of urethral inflammation.

Adult↗
PubMed1991

Impact of nonoperative therapy on the clinical management of peripheral arterial disease.

Nonoperative therapy includes conservative noninterventional modalities and the endovascular interventional modalities of percutaneous transluminal angioplasty and a variety of laser systems and atherectomy devices. The role and impact of all nonoperative treatments are considered in the perspectives of the natural history of lower-extremity arteriosclerosis and its present surgical (operative) treatment. Nonoperative treatments may replace and/or facilitate surgical treatment in operative candidates. Nonoperative methods may also justify treatment in patients who cannot or should not be subjected to surgery. Facts and opinions relating to these uses of nonoperative treatments are presented, and the qualifications and credentialing of individuals who should be treating patients with lower-extremity ischemia resulting from peripheral arteriosclerosis are discussed.

Angioplasty, Balloon↗
PubMed1991

Late results of two hundred seventeen femoropopliteal bypasses to isolated popliteal artery segments.

A 10-year-experience of 217 femoropopliteal bypasses to isolated popliteal artery segments in 207 patients is reported. Thirty-three femoropopliteal bypasses (15%) were performed with reversed saphenous vein and 184 (85%) with polytetrafluoroethylene grafts. Operative indications were gangrene in 121 (56%), nonhealing ulceration in 40 (18%), ischemic rest pain in 51 (24%), and claudication in 5 (2%) cases. The 5-year primary graft patency rate of these bypasses was 59% (reversed saphenous vein, 74%; polytetrafluoroethylene, 55%; p less than 0.05), the secondary 5-year graft patency rate was 61% (reversed saphenous vein, 79%; polytetrafluoroethylene, 56%; p less than 0.05), and the 5-year limb salvage rate was 78% (reversed saphenous vein, 78%; polytetrafluoroethylene, 78%). The 30-day operative mortality rate was 10%, and the 5-year patient survival rate was 38%. Eleven patients (5%) required lower extremity amputation because of progressive gangrene or extensive infection despite a patent bypass to an isolated popliteal artery segment. We conclude that femoropopliteal bypasses to isolated popliteal artery segments (1) have acceptable 5-year graft patency and limb salvage rates; (2) should be performed with reversed saphenous vein grafts when possible; (3) may be performed with polytetrafluoroethylene grafts if necessary, with a resulting limb salvage rate equal to that of reversed saphenous vein grafts; and (4) require sequential extension to an infrapopliteal artery in up to 20% of patients. In addition, the presence of an isolated popliteal artery segment is associated with a high operative mortality rate and limited life expectancy because of coronary artery disease.

Adult↗
PubMed1991

Nonhemophilic hemosiderotic synovitis of the shoulder. A case report.

In a nonhemophilic 72-year-old man, a persistent degenerative hemarthrosis of the shoulder joint was associated with a complete tear of the rotator cuff. Extensive, rusty synovial pigmentation and hyperplasia (hemosiderotic synovitis) mimicking pigmented villonodular synovitis (PVS) were noted at surgery. Spontaneous hemarthrosis of the shoulder includes rapid onset of severe pain, limitation of movement, subsequent appearance of a bruise on the affected shoulder and arm, and radiological evidence of joint degeneration. Hemosiderotic synovitis results from chronic intraarticular bleeding. With the breakdown of trapped hemoglobin, iron-containing hemosiderin is stored in synovial tissue producing rusty discoloration and proliferative reaction. The classic cytoarchitecture of PVS has additional subsynovial nodular proliferation of mononuclear cells. Hemarthrosis may produce significant structural alteration of joints. Its prompt recognition and the awareness of underlying causes should lead to earlier diagnosis, appropriate therapy, less joint destruction, and better outcomes.

Aged↗
PubMed1991

Prospective, randomized comparison of ringed and nonringed polytetrafluoroethylene femoropopliteal bypass grafts: a preliminary report.

Kinking and compression with knee flexion are thought to be one cause of failure of below-knee polytetrafluoroethylene femoropopliteal bypass. To prevent this problem polytetrafluoroethylene grafts externally supported with rigid rings have been developed. The present randomized, prospective study compared ringed and nonringed polytetrafluoroethylene grafts in 122 patients who underwent femoropopliteal bypass for severe limb ischemia. Patients were well matched for surgical indications and risk factors. There was no significant difference in the 3-year graft patency rate of ringed versus nonringed polytetrafluoroethylene femoropopliteal bypasses (74% vs 68%, p = 0.5). Similarly, no significant differences were found in the 3-year graft patency rates of ringed versus non-ringed above-knee (82% vs 74%, p = 0.5) or below-knee polytetrafluoroethylene femoropopliteal bypasses (68% vs 59%, p = 0.5). The 3-year graft patency rate of all above-knee polytetrafluoroethylene femoropopliteal bypasses was slightly greater than that of below-knee polytetrafluoroethylene femoropopliteal bypasses (76% vs 62%), but this difference was not statistically significant (p = 0.25). The 3-year limb salvage rate with ringed polytetrafluoroethylene grafts was 92% compared with 79% for nonringed polytetrafluoroethylene grafts, but this difference was not statistically significant (p = 0.25). Data to date from this study fail to support the recommendation that ringed polytetrafluoroethylene grafts be used preferentially over conventional polytetrafluoroethylene grafts in patients who require femoropopliteal bypass with a synthetic graft.

Adult↗
PubMed1991

Prospective randomized multicenter comparison of in situ and reversed vein infrapopliteal bypasses.

We have performed a prospective, randomized, multicenter study to compare in situ and reversed vein grafts for long limb salvage bypasses from the proximal thigh to an infrapopliteal artery. Three hundred eighty-four patients required an infrapopliteal bypass for critical lower extremity ischemia. Of these, 259 were excluded because a short vein bypass was performed or because the vein was considered inadequate. The remaining 125 patients had a randomized vein bypass, 63 reversed, 62 in situ. The two groups were similar with regard to risk factors, indications, graft dimensions, and outflow. Secondary patency at 30 months was similar for both techniques: reversed 67% +/- 9% (+/- SE); in situ 69% +/- 8%. For veins less than or equal to 3.0 mm in minimum distended diameter 24-month patency rates were 61% +/- 22% for 12 in situ veins and 37% +/- 29% for 10 reversed veins (p greater than 0.05). Angiographic evaluation of failing grafts revealed lesions similar in type and frequency in both types of grafts. These included focal (in situ, n = 4; reversed, n = 7) and diffuse vein hyperplasia (in situ, n = 2; reversed, n = 1), and inflow and outflow stenoses (in situ, n = 4; reversed, n = 3). The incidence of wound complications and the mortality rate were similar for the two groups. These data show no significant difference in overall patency rates for the two types of vein grafts at 2 1/2 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

A G protein mutant that inhibits thrombin and purinergic receptor activation of phospholipase A2.

The stimulation of phospholipase A2 by thrombin and type 2 (P2)-purinergic receptor agonists in Chinese hamster ovary cells is mediated by the G protein Gi. To delineate alpha chain regulatory regions responsible for control of phospholipase A2, chimeric cDNAs were constructed in which different lengths of the alpha subunit of Gs (alpha s) were replaced with the corresponding sequence of the Gi alpha subunit (alpha i2). When a carboxyl-terminal chimera alpha s-i(38), which has the last 38 amino acids of alpha s substituted with the last 36 residues of alpha i2, was expressed in Chinese hamster ovary cells, the receptor-stimulated phospholipase A2 activity was inhibited, although the chimera could still activate adenylyl cyclase. Thus, alpha s-i(38) is an active alpha s, but also a dominant negative alpha i molecule, indicating that the last 36 amino acids of alpha i2 are a critical domain for G protein regulation of phospholipase A2 activity.

Adenosine Triphosphate↗