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Biomedical subjects

N K Reddy

Publications and source records attributed to N K Reddy.

18 recordsLinked to original sources
PubMed1997

Evaluation of fluorine-18-BPA-fructose for boron neutron capture treatment planning.

UNLABELLED: Boron neutron capture therapy (BNCT) using 4-[10B]boronophenylalanine-fructose (BPA-Fr) is in Phase II clinical trials to validate BNCT as a treatment for glioblastoma multiforme and melanoma. Successful BNCT depends on knowledge of the distribution of boron-containing agents in both tumor and normal tissue as currently determined by chemical confirmation of boron deposition in surgically removed malignant tissue before BNCT. METHODS: We used PET to noninvasively obtain in vivo information on the pharmacokinetics of the 18F-labeled analog of BPA-Fr in two patients with glioblastoma multiforme. Time-activity curves generated from the bolus injection of 18F-BPA-Fr were coinvolved to simulate a continuous infusion used for BNCT therapy. RESULTS: Distribution of 18F-BPA-Fr by PET was found to be consistent with tumor as identified by MR imaging. The 18F-BPA-Fr tumor-to-normal brain uptake ratio was 1.9 in Patient 1 and 3.1 in Patient 2 at 52 min after injection. The 18F-BPA-Fr uptake ratio in glioblastoma paralleled that of nonlabeled BPA-Fr seen in patients as previously determined by boron analysis of human glioblastoma tissue obtained from pre-BNCT surgical biopsy. CONCLUSION: Knowledge of the biodistribution of BPA-Fr enables pre-BNCT calculation of expected tissue dosimetry for a selected dose of BPA-Fr at a specific neutron exposure. Fluorine-18-BPA-Fr PET is capable of providing in vivo BPA-Fr biodistribution data that may prove valuable for patient selection and pre-BNCT treatment planning.

Boron Compounds↗
PubMed1994

Thrombolysis in left-sided prosthetic valve occlusion: immediate and follow-up results.

Thrombolytic therapy is used increasingly for prosthetic valve thrombosis. Fear of peripheral embolism has limited its use in left-sided valve occlusions. Thirty-eight patients with prosthetic valve occlusion were treated with thrombolytic agents on 44 occasions. Duration of thrombolytic therapy was individualized. Patients were followed up with clinical, echocardiographic, and cine-fluoroscopic evaluation. Average time from onset of symptoms to presentation was 9.7 days. The anticoagulation status was inadequate in 70% of instances. The majority (75%) were in functional class IV, 8 of them being in shock. Overall success was seen in 88.6%: immediate complete success in 18 and partial in 21. Nine of those with partial success had delayed opening of the leaflets. There were nine instances of rethrombosis and one instance of re-rethrombosis; 6 patients received repeat thrombolysis with success in 5. Seventy-six percent (29/38) of the patients were surviving at the time of reporting. In conclusion, the present study demonstrates the feasibility of thrombolytic therapy for left-sided prosthetic valve occlusion. Delayed opening is common in patients with initial partial success. Rethrombosis remains a major problem.

Adolescent↗
PubMed1992

Multidisciplinary preoperative assessment and late function in dysvascular amputees.

During a three-year period, 95 adults were treated by lower-extremity amputations for peripheral vascular insufficiency. A multidisciplinary team for presurgical evaluation determined all to be potentially independent walkers with a prosthesis. Patients were graded for level of independent walking before amputation and again at a minimum two-year follow-up examination using a seven-level functional grading system. Seventy-six of 90 patients (84%) ambulated within one functional level of their preamputation status. This return to preamputation level of function was maintained whether comparing preamputation functional level or surgical amputation level. Prosthetic use increased and the use of walking aids decreased with increased functional ambulation levels, but did not correlate with surgical levels. Peripheral vascular insufficiency patients can maintain walking independence. Multidisciplinary presurgical evaluation helps selection of the amputation level and correct prosthetic limb fitting.

Adult↗
PubMed1987

Pulmonary atresia with ventricular septal defect in adult patients.

Hemodynamic data and angiograms of 15 adult patients with pulmonary atresia and ventricular septal defect were reviewed to assess the pulmonary circulation and other associated features. The most common variety of pulmonary atresia was that of pulmonary valve, main pulmonary artery, and the confluence of pulmonary arteries (6 cases, 40%). The collateral vessels to the lungs were well developed in all cases; selective injections into the collateral vessels were of great value in their delineation. The left ventricle was well developed in 11 cases (73.3%). Congestive heart failure was seen in 8 (53.3%), tricuspid regurgitation in 10 (66.7%), and aortic regurgitation in 7 (46.7%) cases. The long survival in these patients was related to the favorable anatomy of central pulmonary arteries (12 cases, 80%) and adequate pulmonary collateral circulation.

Adolescent↗
PubMed1987

Supernumerary right coronary artery.

A rare case of a patient with supernumerary right coronary artery in whom the two vessels arose from the right coronary sinus from two separate ostia adjacent to each other is presented. The smaller vessel gave off the sinoatrial nodal branch and the posterior descending artery whereas the larger one gave off the conus branch, the right ventricular branches, and continued as acute marginal branch. This is the first case report in the English literature.

Adult↗
PubMed1986

Enhancement of thrombolysis with tissue-type plasminogen activator by pretreatment with heparin.

The effect of pretreatment with heparin on lysis of arterial thrombi by tissue-type plasminogen activator (rt-PA) was studied in 19 dogs. Copper coil-induced carotid artery thrombi were weighed, inserted into the femoral arteries, and exposed to a 15 min infusion of rt-PA at 10 micrograms/kg/min either with (n = 6 thrombi) or without pretreatment with a 200 unit/kg bolus of heparin (n = 6 thrombi). The infusion of rt-PA without pretreatment reduced the thrombus weight by 27.6 +/- 7.4%, while infusion of rt-PA with pretreatment reduced it by 79.1 +/- 12.3% (p less than .0001). To test the hypothesis that heparin enhanced thrombolysis by preventing continued incorporation of new fibrin into the thrombus during thrombolysis we repeated the experiments using pretreatment with 8 U/kg of ancrod, which rapidly depletes fibrinogen. Pretreatment with ancrod (n = 6 thrombi) depleted fibrinogen and enhanced the lytic effect of rt-PA to a similar degree as pretreatment with heparin, resulting in a 67.6 +/- 12.3% (NS) decrease in thrombus weight. We conclude that heparin significantly enhances the thrombolytic effect of rt-PA, probably by preventing new fibrin formation and its incorporation into the thrombus during lysis.

Ancrod↗
PubMed1986

Diabetic neuro-osteoarthropathy. Rehabilitation of a patient with both ankle joints involved and associated skin problems.

Neuro-osteoarthropathy in diabetes mellitus is not rare. The case of a 53-year-old diabetic with involvement of both ankle joints and multiple associated skin problems complicating rehabilitation management is discussed. By applying a team approach, closely monitoring the patient's skin and joint problems, and treating them at an early stage by adaptive shoes and orthoses, we found that function could be sustained at an optimal level for a prolonged period. In addition to prevention of ulceration, modifying the weight bearing or temporarily non-weight bearing is the treatment of choice. Amputation is to be considered only as a last resort.

Ankle Joint↗
PubMed1984

Response of hepatocytes transplanted into syngeneic hosts and heterotransplanted into athymic nude mice to peroxisome proliferators.

The development of a transplantation system by which rat hepatocytes can be implanted and remain viable in the dorsal fascia of two-thirds hepatectomized syngeneic hosts provides an opportunity to examine whether such transplanted hepatocytes retain the capacity to recognize and respond to the peroxisome proliferators 2-[4-(2,2- dichlorocyclopropyl )phenoxy]-2- methylpropionic acid (ciprofibrate), a hypolipidemic drug, and di-(2-ethylhexyl)phthalate (DEHP), an industrial plasticizer. Male F344 rats with transplanted rat hepatocytes were fed a control diet or a diet containing either 0.05% ciprofibrate (w/w) or 2% DEHP (v/w). After 4 weeks, the animals were sacrificed, and transplanted hepatocytes revealed a significant increase in the numerical density of peroxisomes in both ciprofibrate- and DEHP-fed rats. The volume density of peroxisomes in transplanted hepatocytes increased 9.2- and 5.3-fold, respectively, in ciprofibrate- and DEHP-fed rats, whereas the volume density of mitochondria remained essentially unchanged. The magnitude of increase in peroxisome volume density in transplanted hepatocytes was comparable to increases in the volume density of these organelles in the liver parenchymal cells of syngeneic hosts. The present study also demonstrates that hepatocytes isolated from cat liver and heterotransplanted into partially hepatectomized athymic nude mice retain their biological integrity and respond to the peroxisome proliferative effect of ciprofibrate. This observation suggests the possibility that hepatocytes obtained from small segments of liver of humans, primates, and other species and heterotransplanted into nude mice might provide a valuable model system for toxicological evaluation of chemicals. These studies suggest that hepatocytes, irrespective of their location in the body, recognize the peroxisome proliferator or its active metabolite(s), which stimulates the expression of peroxisome-specific genes in these cells.

Animals↗
PubMed1984

Differentiation of pancreatic acinar carcinoma cells cultured on rat testicular seminiferous tubular basement membranes.

The use of rat testicular seminiferous tubular basement membrane (STBM) segments as a model substratum for the in vitro maintenance of tumor cells dissociated from a transplantable pancreatic acinar rat carcinoma (J. K. Reddy and M. S. Rao, Science (Wash. DC), 198: 78-80, 1977) is described. Ultrastructurally pure, hollow tubular segments of STBM were prepared by mechanical disaggregation, DNase digestion, and deoxycholate treatment. Dissociated pancreatic acinar carcinoma cells adhered readily to STBM segments within 1 to 6 hr, and these STBM-tumor cell aggregates were maintained for up to 7 days in serum-free chemically defined medium supplemented with hydrocortisone, insulin, vitamin C, and soybean trypsin inhibitor. The tumor cells formed acinar-like clusters and displayed intercellular junctions and polarization of secretory granules toward the center of these clusters. By 4 days, virtually all cells of this acinar carcinoma maintained on STBM in supplemented chemically defined medium contained numerous secretory granules. Cell replication, as determined by [3H]thymidine autoradiography, ceased within 18 hr of attachment of neoplastic cells to STBM; however, all cells incorporated [3H]leucine as evidenced by light and electron microscopic autoradiography. In addition, two-dimensional analysis and fluorography of newly synthesized secretory proteins discharged by these cells in response to carbamylcholine revealed the presence of Mr 24,000 protein and 19 other secretory proteins characteristic of this tumor (L. J. Hansen, M. K. Reddy, and J. K. Reddy, Proc. Natl. Acad. Sci. USA, 80: 4379-4383, 1983). The culture system utilizing STBM and supplemented chemically defined medium should allow investigation of the effects of a variety of factors on morphogenesis, cytodifferentiation, and gene expression in pancreatic acinar tumors.

Animals↗
PubMed1983

Revascularization surgery: impact on lower extremity amputations.

The effect of revascularization surgery on the amputee population of 2 hospitals (VA and private) was studied in 2 time periods a decade apart--1969-70 and 1979-80. In the VA hospital there was a trend toward below-knee surgery over time; however, for patients who had prior vascular reconstruction and who ultimately came to amputation there was no change in the proportion of below-knee to above-knee surgery at either hospital. At the private hospital the average age of patients who underwent amputation increased significantly and the proportion of patients requiring amputation to the total number of patients undergoing vascular reconstruction significantly decreased in the later time period.

Aged↗
PubMedDate not supplied

Total occlusion of the left main coronary artery in chronic stable angina pectoris.

We present the clinical and angiographic profile of three patients with class I stable angina pectoris. All had strong coronary risk factors, and stress testing was positive in stage one of the Bruce protocol. Coronary angiography revealed total occlusion of the left main coronary artery (LMCA), and aortocoronary bypass surgery was performed. Thus, total LMCA occlusion may be an unexpected angiographic finding in patients with class I angina.

Adult↗
PubMedDate not supplied

Prospective observational study of primary angioplasty of the infarct-related artery for acute myocardial infarction.

Primary angioplasty has been shown to reduce rates of in-hospital mortality, recurrent ischaemia and infarction. However, the role of primary stenting and abciximab is presently undergoing evaluation. This study attempted to examine the feasibility, safety and outcomes of primary angioplasty in the treatment of acute myocardial infarction. Data in 100 patients who underwent primary angioplasty for evolving acute myocardial infarction was prospectively analysed to assess the safety and efficacy of various modalities. Twenty patients were in Killip class III and above. Multivessel (2 or more vessels) disease was noted in more than 52 cases. Procedural success was 99 percent; 86 patients received primary stenting, majority of them had Kalam-Raju stent implantation. Adjunct treatment included abciximab infusion in 22 and intra-aortic balloon pump support in 12. Overall mortality rate was six percent with a mortality of 2.2 percent in non-cardiogenic shock patients. Recurrent ischaemic events were noted in five, three of them had successful reperfusion with repeat angioplasty. None of the patients had emergency coronary artery bypass surgery. It is concluded that primary angioplasty is safe and effective with high procedural success. Recurrent ischaemic events are low, possibly due to routine use of stenting and selective use of abciximab.

Abciximab↗
PubMedDate not supplied

A study of clinical efficacy of sildenafil in patients with primary pulmonary hypertension.

BACKGROUND: Primary pulmonary hypertension is a disorder with limited treatment options and poor outcome. Sildenafil, a pulmonary vasodilator, is likely to be beneficial in primary pulmonary hypertension. We studied the clinical efficacy of sildenafil in patients with primary pulmonary hypertension. METHODS AND RESULTS: A registry of patients with primary pulmonary hypertension has been maintained in our hospital since January 1999. Of a total of 60 patients. 29 (M:16, F:13) consented to try sildenafiL. New York Heart Association functional class, six-minute walk test and Doppler echocardiographic evaluation of pulmonary artery pressure was done before and after treatment with sildenafil. Sildenafil was initiated at a dose of 25 mg thrice a day and increased up to 100 mg thrice a day as tolerated. There was a significant improvement in the functional class. The six-minute walked distance increased from 297.07+/-130.69 m at baseline to 427.68+/-85.35 m after 3 months of sildenafil therapy (p<0.0003). The mean of the pulmonary artery systolic pressure before starting sildenaffil was 109.26+/-24.15 mmHg (mean+/-SD) and it decreased to 95.15+/-24.64 mmHg (p<0.008). While 19 of the 31 historical controls in whom sildenafil was not given died during follow-up (11-44 months), only 1 of the 29 patients given sildenafil died (in an accident) during follow-up (5-20 months). CONCLUSIONS: Sildenafil, a pulmonary vasodilator, has a beneficial effect in patients with primary pulmonary hypertension in improving the functional class, six-minute walked distance and in decreasing the pulmonary artery pressures.

Adolescent↗
PubMedDate not supplied

Clinical evaluation of new balloon mountable coil stent: in-hospital and follow-up results.

The purpose of this study was to determine the feasibility, safety and efficacy of elective deployment of a new coil-stent (KR stent) in patients with coronary artery disease. KR stent deployment was attempted in 100 patients (135 lesions) enrolled prospectively at a single centre from December 1996 to March 1997. Ten, 15, 18, 24, and 32 mm long KR stents were manually crimped onto balloons and deployed in native coronary artery lesions. Majority of the patients had recent acute coronary syndromes (unstable angina 30% and post-myocardial infarction angina 56%). Diabetes was present in 34 percent of the patients. Fifty-six percent had single-vessel and 44 percent multi-vessel disease. In 38 percent, the lesions were located in proximal segments and 40 percent of lesions were long. KR stents were successfully deployed in 98 percent of patients. Mean minimal luminal diameter increased by 2.89 +/- 0.63 mm (from 0.57 +/- 0.38 mm before to 3.45 +/- 0.56 mm after the procedure). Mean percent diameter stenosis decreased from 83.33 +/- 10.84 percent before to 3.38 +/- 5.74 percent after the stent deployment. Mean reference vessel diameter was 3.45 +/- 0.56 mm. There were occasional technical complications including balloon rupture (1), stent migration (2) and distal embolisation of atheromatous material (1). One patient developed subacute stent thrombosis. There were no other major in-hospital cardiovascular events. At the end of six-month follow-up, there were no myocardial infarction or death. Six patients presented with recurrence of symptoms within six-months of the procedure, four of whom underwent target vessel revascularisation procedure. In conclusion, the in-hospital and six-month follow-up clinical results were highly encouraging with KR stent. Successful deployment rates were high despite unfavourable clinical and angiographic background. Low clinical events on follow-up will make it suitable for elective stenting.

Adult↗