Competing patterns in the Faraday experiment.
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Journal Article↗
Biomedical subjects
K Kumar
Publications and source records attributed to K Kumar.
Extraperitonealization for sigmoid volvulus: a reappraisal.
A prospective study was carried out in a university hospital to evaluate the results of extraperitonealization of the sigmoid colon in non-gangrenous sigmoid volvulus. Eighty-eight patients with non-gangrenous sigmoid volvulus were operated upon using the technique of extraperitonealization of the sigmoid colon. There was no recurrence of the volvulus at 1 to 6 years follow up but 8 patients (9.1%) had constipation and 2 patients (2.2%) had distension of the lower abdomen. Extraperitonealization of the sigmoid colon is a reasonable non-resection alternative for non-gangrenous sigmoid volvulus and has minimal morbidity, mortality and no recurrence in our series.
Adolescent↗
Endovascular repair of an ascending aorta-to-left common femoral artery graft with aneurysmal degeneration.
PURPOSE: To report the use of endovascular grafting to repair degenerative aneurysmal changes in an extra-anatomic bypass graft. METHODS: A 14-year-old extra-anatomic ascending aorta-to-left common femoral bypass graft ("ventral aorta") had undergone aneurysmal degeneration, producing symptoms of progressive claudication and local abdominal swelling. The aneurysmal graft dilatation began within the thoracic cavity and extended through the entire extraperitoneal abdominal segment. The option for minimally invasive repair using a customized stent-graft device was offered to the patient as an alternative to standard reoperation. RESULTS: An 8-mm x 42-cm endovascular graft was constructed by polytetrafluoroethylene with 30-mm Palmaz stents sutured to each end. With balloon occlusion of antegrade and retrograde blood flow, the stent-graft was delivered retrograde through an incision in the distal end of the existing bypass graft. The device was successfully positioned and deployed with complete exclusion of the aneurysm. No complications occurred, and the patient's symptoms abated. Follow-up arteriography at 1 months showed a pseudoaneurysm at the distal graft incision site; surgical repair was necessary. At 6 months, angiography demonstrated continued patency of the extra-anatomic bypass graft. CONCLUSIONS: Intraluminal aneurysm exclusion techniques in degenerated extra-anatomic bypass grafts may evolve into a viable therapeutic alternative to complex reoperative surgery.
Aged↗
Platelet function studies in Indian kala-azar.
Platelet function studies were conducted on 25 parasitologically positive cases of Indian kala-azar and 25 age and sex matched healthy controls. Ninety-two per cent of patients had thrombocytopenia of variable degree; in 44% of patients, platelets were less than 60,000 mm-3. The platelet adhesive index was less than 30% in 70% of patients with kala-azar (normal 31-60%). Platelet aggregation time with ADP and adrenaline was abnormally prolonged compared to the controls. Platelet factor III availability was poor in 40% of cases. There was a fair degree of correlation between platelet adhesiveness and platelet factor III availability in these patients: 50% of patients with poor platelet adhesiveness showed reduced platelet factor III availability.
Blood Platelets↗
Effect of tamoxifen on plasma lipids and lipoproteins in postmenopausal women with breast cancer.
BACKGROUND: Adjuvant tamoxifen therapy is given to large and increasing numbers of women with early-stage breast cancer. The effects of this drug on plasma lipids and lipoprotein profiles are important, because cardiovascular disease also develops over time in a large percentage of tamoxifen-treated postmenopausal women. The purpose of the study was to evaluate the effects of tamoxifen on plasma lipid and lipoprotein profiles in postmenopausal Indian women who were disease-free after primary treatment for breast cancer. METHODS: A short-term evaluation of 6 months of tamoxifen therapy (10 mg twice a day) in 45 postmenopausal women was conducted. The plasma lipids and lipoprotein levels were evaluated before and after 3 and 6 months of tamoxifen treatment. RESULTS: At 3 and 6 months' evaluation, patients receiving tamoxifen showed significantly decreased levels of total cholesterol, free cholesterol, and low-density lipoprotein cholesterol (P < 0.001 for each) and increased levels of plasma triglycerides, free fatty acids, very low density lipoprotein cholesterol, and high-density lipoprotein cholesterol. CONCLUSION: The results suggest that tamoxifen therapy benefits postmenopausal patients with breast cancer, with likely reduction in the risk of cardiovascular disease.
Breast Neoplasms↗
Screening for breast cancer. Screening programme not cost effective.
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Breast Neoplasms↗
Percutaneous deployment of a polytetrafluoroethylene (PTFE) graft to repair a pseudoaneurysm produced by a graft to graft anastomotic dehiscence.
Arterial injuries, creating a pseudonauerysm or arteriovenous fistula have, in the main, been managed through surgical ligation of the involved segments, arterial reconstruction, embolization of the involved artery, and percutaneous placement of a stented graft [Marin ML, et al: J Vasc Surg 18:299-302, 1993]. This communication describes the percutaneous repair of a large popliteal pseudoaneurysm, created by dehiscence of the anastomotic suture line of a composite polytetrafluoroethylene (PTFE) femoropopliteal and a popliteal-posterior tibial graft using a PTFE graft without stent assistance.
Aged↗
Post-ischemic changes in protein kinase C RNA in the gerbil brain following prolonged periods of recirculation: a phosphorimaging study.
Northern blot analysis was performed to investigate the long-term changes in mRNA expression of protein kinase C (PKC) in the gerbil brain following transient cerebral ischemia. We have previously demonstrated an increase in mRNA levels of certain Ca(2+)-independent forms of PKC in early recirculation periods i.e., 6 h and 24 h postischemia (PI). But, since neuronal death in susceptible regions usually occurs 2-3 days following ischemia, this study examined the mRNA levels of PKC after prolonged periods of reperfusion following ischemia. The mRNA expression was also examined at an early recirculation period, i.e., 1 h, to determine how early the alterations begin to occur. Global forebrain ischemia was produced in gerbils by 10 min of bilateral carotid artery occlusion. RNA was prepared from forebrains of nonischemic controls and PI animals following 1 h, 3 d, and 7 d of recirculation (n = 3 to 4 in each group) and hybridized with synthetic oligonucleotide probes for PKC, delta, epsilon, and zeta based on cDNA sequences in rat and labelled with 32P. The autoradiographs were recorded and quantified by a sensitive system, Phosphor Imager, followed by conventional x-ray film exposure. The mRNA levels of all 3 PKC isozymes examined were found to be elevated as early as 1 h recirculation following ischemia. The increases in mRNA levels of both delta PKC following 6 h and 24 h of recirculation as well as that of zeta PKC following 24 h of recirculation, as reported earlier, return to control levels by 3 d PI and remain at that level 7 d PI.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
mRNA levels of Ca(2+)-independent forms of protein kinase C in postischemic gerbil brain by northern blot analysis.
To investigate the role of Ca(2+)-independent forms of protein kinase C (PKC) in ischemic neuronal injury, mRNA expression of PKC was studied by Northern blot analysis. Ischemia was produced in gerbils by 10-min bilateral carotid artery occlusion and was followed by recirculation for 15 min, 6 h, and 24 h. Brains of postischemic and sham-operated animals were removed, forebrains fresh frozen, and processed for Northern blot analysis. Three synthetic oligonucleotide probes based on published cDNA sequences of rat brain PKC for the isozymes delta, epsilon, and zeta were utilized for hybridization. Northern blot analysis showed increased hybridization signal for all three PKC isozymes examined in the 6- and 24-h postischemic groups. Of these, the twofold increases in the expression of PKC delta and zeta were statistically significant in comparison to the control. These results suggest that the mRNA levels of Ca(2+)-independent forms of PKC, in particular, delta and zeta, are temporally stimulated by ischemic injury in the brain and may imply an important role of the enzyme in postischemic neuronal damage. However, since the protein itself was not examined in this study, the significance of the increased expression cannot be ascertained. However, it may reflect a compensatory response to the loss of PKC reported to occur in the reperfusion phase.
Analysis of Variance↗
Sub-mitral aneurysm with aortoarteritis: case report of an unusual association.
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Adult↗
Innovative interactive videodisc units for teaching of pathology laboratory cases. Five years' experience.
Seven computer-assisted interactive videodisc instruction units, based on laboratory cases in the General Pathology course for first-year medical students, were developed. Images from the laser videodisc Slice of Life, contributed previously by one of the authors, and the program "Hypercard stack 2.1" were used to develop these units to provide students with interactive software for independent supplemental review of the laboratory cases studied in the course. With the dual-screen system developed, specific picture frames from the videodisc are retrieved on one screen while the other screen displays the corresponding text. The seven units include two units each on cell injury, inflammation, and neoplasia, and one on opportunistic infections. Each unit contains several case studies, each of which consists of the following: a clinical profile, gross pictures and description of the tissue removed, sequential photomicrographs at successively higher magnifications from various fields of tissue slides and their descriptions, comparison with normal histology of the organ involved, interpretation of the observations and comments, final diagnosis, and a quiz. The histopathologic features are specifically emphasized with programmed, computer-generated pointers to indicate specific cells or structures on the images. Each case also contains a glossary to define terms not familiar to first-year students. Although no comparative performance data are available, evaluation of the units obtained from nine terms of use in the last 5 years indicates that these units are extremely valuable supplemental tools for students for independent review of the laboratory cases.
Computer-Assisted Instruction↗
The use of Gianturco-Roubin flexible metallic coronary stents in old saphenous vein grafts: in-hospital outcome and 7 day angiographic patency.
After placement of a Gianturco-Roubin metallic, coiled coronary stent(s) following balloon angioplasty (PTCA), a pre-discharge (7 day) angiogram determined the patency of the old coronary bypass vein graft(s) (SVG) (> or = 5 years remote from their last surgery, mean age: 8.5 +/- 1.8 years). Metallic, coiled stents were successfully deployed in 95/96 (99%) patients within 100/101 (99%) SVGs. The indications for deployment were threatened [81 patients (84%)] or acute [15 patients (16%)] vein graft closure following PTCA. Intragraft urokinase infusion was performed in 17 patients (17%) [6 patients with baseline occlusions; 11 with abrupt closure post PTCA]. Complications encountered included three (3%) in-hospital deaths (two procedure related) two (2%) Q wave myocardial infarctions, six (6%) non-Q wave myocardial infarctions, and 22 (22%) bleeding problems. These included, not mutually exclusively, 21 (22%) requiring transfusions, six (6%) cases of gastrointestinal bleeding, six (6%) pseudoaneurysms, five (5%) retroperitoneal haemorrhages and two (2%) cerebrovascular accidents. All patients received dipyridamole, aspirin, dextran, and anticoagulation (heparin 10-20,000 U intra-procedurally); a heparin infusion was continued for 5 +/- 1 days, despite warfarin administration which attained a therapeutic prothrombin time (PT) (1.5-2 times control) by 3 +/- 1 days. Out of the 95 successfully treated patients, six with eight stented grafts were ineligible for pre-discharge angiography. Of the six, three died in hospital (four SVGs), one had an intracerebral haemorrhage (one SVG), and two were asymptomatic patients with chronic renal failure (three SVGs).(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Fast computed tomography detection of coronary calcification in the diagnosis of coronary artery disease. Comparison with angiography in patients < 50 years old.
BACKGROUND: The predominant cause of coronary artery calcification is atherosclerosis. Although fast x-ray computed tomography (CT) has been demonstrated to be a sensitive technique to detect coronary calcification, the increasing prevalence of calcification with age has been associated with a low specificity for identifying obstructive atherosclerosis. We hypothesized that the specificity of this test would be improved in a younger patient population, making it more useful in the diagnosis of coronary artery disease. METHODS AND RESULTS: We compared fast CT-detected calcification with coronary angiography in 106 patients under the age of 50 years. Nonenhanced fast CT scans consisting of 20 contiguous 3-mm tomograms of the proximal coronary arteries were obtained during a single breath hold. A positive scan was defined as 4 contiguous voxels (> or = 1 mm2) of density > 130 Hounsfield units in the region of the epicardial coronary arteries. Calcification detected by fast CT had an 85% sensitivity to predict patients with significant coronary artery disease (> or = 50% diameter stenosis), with a specificity of 45%. Although the sensitivity to detect multivessel disease was 94%, the sensitivity to detect single-vessel disease was 75%. Changing the threshold for defining a positive fast CT scan from 4 to 2 contiguous voxels produced a small improvement in sensitivity, to 88%, but reduced specificity to 36%. CONCLUSIONS: Although the specificity to detect angiographically significant coronary disease with fast CT improves in a younger patient population, it continues to be relatively low. In contrast to older patient populations, a small but significant number of patients < 50 years old with angiographically significant coronary artery disease do not have coronary calcification demonstrated by fast CT. Thus, caution should be used in excluding significant coronary artery disease on the basis of a negative fast CT study.
Adult↗
Down's syndrome with acute myeloid leukemia.
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Child↗
Plasma cell leukemia--report on two cases.
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Antineoplastic Combined Chemotherapy Protocols↗
Three-dimensional structural resemblance between the ribonuclease H and connection domains of HIV reverse transcriptase and the ATPase fold revealed using graph theoretical techniques.
Using 3D searching techniques based on algorithms derived from graph theory, we have established two previously unreported structural similarities involving the ribonuclease H (RNase H) domain of HIV-1 reverse transcriptase (RT). First, we report that there is a strong similarity between the 3D folds of the RNase H domain of RT and the 'ATPase folds' of hexokinase, the 70 kDa heat-shock cognate protein and actin. Like RNase H, these enzymes are involved in nucleotide binding and metal ion-catalysed cleavage of a phosphodiester bond. Similarities of the folding motif and the position of the metal-binding site in these enzymes suggest possible functional analogies and evolutionary relationships with RNase H. Second, we find there is a strong resemblance between the folds of the RNase H domain and of the p66 and p51 'connection' domains of RT. It is possible that this striking similarity within the RT structure indicates a possible ancestral gene doubling event. The similarity may also indicate that the connection domains possess functional roles in addition to those previously suggested, and they may therefore represent a further target for the design of therapeutic agents.
Adenosine Triphosphatases↗
Use of the stiff shaft, straight Terumo Glidewire in crossing stenotic aortic valves.
One of the more difficult and time-consuming diagnostic procedures in the cardiac catheterization laboratory is retrograde crossing of the severely stenotic aortic valve. Whereas patients with advanced aortic stenosis tend to be complicated and elderly, lengthy procedures can lead to a higher incidence of thrombo-embolic and vascular complications and relatively greater procedural blood loss. This report concerns the use of the Terumo Glidewire to facilitate passage through stenotic and tortuous peripheral arteries.
Aortic Valve Stenosis↗
Comparison of alpha-tubulin mRNA and heat shock protein-70 mRNA in gerbil brain following 10 min of ischemia.
In situ hybridization and Northern blot analysis were used to characterize the mRNA expression of alpha-tubulin, a neuroprotein crucial for neuronal structural and functional restoration, in comparison to that of the stress inducible heat shock protein-70 (HSP-70), in the same gerbil brain following 10 min of forebrain ischemia. The HSP-70 expression was noted in the dentate granule layer 1 h postischemia (PI) and became prominent in all pyramidal cell fields of the hippocampus in addition to the dentate layer at 6 h PI. The induction of HSP-70 persisted in CA1 and CA2 regions and partly in dentate gyrus for up to the 1 day PI period examined. There was no significant HSP-70 expression in any of the regions of the nonischemic or 15 min PI brain. alpha-Tubulin, on the other hand, was expressed in all pyramidal fields of the hippocampus as well as dentate gyrus in nonischemic controls. A decline was noted in the CA1 region 1 h PI onward and was maximal at 6 h PI. Its expression, however, increased at 24 h PI (significant only in comparison to 15 min and 6 h PI but not to control) when it became rather strong in the dentate gyrus. Thus, the temporal pattern of expression of alpha-tubulin sharply contrasted with that of HSP-70 in the PI brain as it declined in the vulnerable CA1 region during the 1st 24 h PI, i.e., the period when HSP-70 was induced and its expression was lowest in the 6 h group when HSP-70 peaked. It was maximum in the dentate gyrus at 24 h PI when HSP-70 was marginally detectable in that region. These studies indicate that in early recirculation period following prolonged ischemia, HSP-70 mRNA is expressed in both vulnerable regions as well as in regions of the brain that are destined to survive while alpha-tubulin is diminished in vulnerable regions. These data suggest a positive correlation between the loss of alpha-tubulin mRNA and delayed neuronal necrosis that follows in the vulnerable CA1 region.
Animals↗