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Biomedical subjects

P Steele

Publications and source records attributed to P Steele.

At least 109 records · Page 6Linked to original sources
PubMed1975

Platelet survival time following aortic valve replacement.

Thromboembolism continues to complicate the course of patients following aortic valve replacement. In patients with prosthetic and homograft mitral valves, platelet survival time has been shown to correlate with occurrence of thromboembolism. This study extends these observations to patients with aortic valve disease. Platelet survival time was measured (by the chromium-51 method) in 73 patients with aortic valve disease. Eighteen patients were studied preoperatively and had platelet survival times of 3.4 plus or minus 0.14 days (mean plus or minus standard error of the mean), almost the same as normal (3.7 plus or minus 0.4 days). Platelet survival time was shortened (P less than 0.001) following aortic valve replacement with Starr-Edwards prosthesis - Model 1000: 2.5 plus or minus 0.13 days (N = 6); Model 1200-1260: 3.0 plus or minus 0.10 (n = 14); model 2300-2320: 3.0 plus or minus 0.15 days (N = 9) - and with stented aortic homografts: 3.0 plus or minus 0.10 days (N = 16). Platelet survival time was normal following aortic valve replacement in patients with directly sewn aortic homografts 3.7 dats plus or minus 0.24 days (N = 10). Eleven patients with Starr-Edwards prostheses had a history of thromboembolism and all also showed shortened platelet survival time (2.7 plus or minus 0.12 days, P less than 0.001), a measurement which was significantly different (P less than 0.01) from the 18 patients with Starr-Edwards prostheses and no thromboembolism (3.0 plus or minus 0.09 days). Platelet suppressant therapy prolonged platelet survival in eight patients with Starr-Edwards devices, thromboembolism, and shortened platelet survival time. These results suggest that insertion of Starr-Edwards valves and stented aortic homografts alter platelet survival time but that direct homografts do not. A correlation between occurrence of thromboembolism after aortic valve replacement and shortened platelet survival time has been shown.

Adult↗
PubMed1975

Effects of clofibrate and sulfinpyrazone on platelet survival time in coronary artery disease.

Platelet survival time was measured (autologous labelling with 51chromium) in 68 men with coronary artery disease (CAD). Survival was shortened slightly (3.2 +/- 0.04 days; mean +/- SEM) as compared to normal (3.7 +/- 0.04 days; N = 18; P less than 0.001), and 60% had shortened survival (less than 3.3 days). Thirty-seven had hyperlipoproteinemia (36 with Type IV and one with Type III) and platelet survival was shortened (3.1 +/- 0.10 days) and significantly different from survival of men with normal lipoproteins (3.3 +/- 0,12 days; P less than 0.05). Twenty-two with shortened platelet survival and CAD received either clofibrate or sulfinpyrazone. Clofibrate prolonged platelet survival (2.6 +/- 0.09 to 3.4 +/- 0,14 days; P less than 0.001) and ten of 12 had prolongation of survival. Sulfinpyrazone increased survival (2.8 +/- 0.12 to 3.6 +/- 0.21; P less than 0.001) and nine of ten had prolognation of platelet survival. Clofibrate lowered serum cholesterol and tryglyceride but alteration in lipids did not correlate with alteration of survival. Sulfinpyrazone did not alter lipids. Data suggest that survival is shortened in CAD and that clofibrate and sulfinpyrazone alter survival. Platelet suppressant agents may prove beneficial in reducing the extent and complications of atherosclerotic arterial injury.

Adult↗
PubMedDate not supplied

Trial of dipyridamole-aspirin in recurring venous thrombosis.

38 patients (26 men) with recurring venous thromboembolism (RVTE) were enrolled in a prospective double-blind, placebo-controlled trial of dipyridamole (DPY), 100 mg a day, and aspirin (ASA), 1200 mg a day. Platelet survival (51Cr labelling of autologous platelets) was measured every 6 months for 18 months. 19 patients were randomised to treatment with DPY and ASA, and 1 had new venous thrombosis (after 15 months of treatment); 19 received placebo and 7 had new venous thrombosis (4--16 months later (chi 2 = 5.70; p< 0.05). DPY-ASA increased platelet survival whereas placebo treatment did not. The results suggest that in patients with RVTE and abnormal platelet survival time DPY in combination with ASA decreases the frequency of new venous thrombosis. Peptic ulcers developed in 2 patients treated with DPY-ASA.

Adult↗
PubMedDate not supplied

Multilobated large B-cell lymphoma diagnosed cytologically. A case report.

BACKGROUND: Fine needle aspiration (FNA) biopsy can be used to reliably classify most conditions involving lymph nodes or, at least, significantly reduce the differential diagnosis. CASE: A 70-year-old male presented with an ulcerated mass arising from the left tonsillar fossa and involving the anterior and posterior pillars. A biopsy of the tonsillar mass performed at an outside hospital was interpreted as a large cell undifferentiated carcinoma. Subsequently the patient developed systemic lymphadenopathy. A bone scan showed intense uptake within the medial tibial plateau of the left knee. FNA biopsy of the right axillary mass was interpreted at University of Cincinnati Medical College as a large cell lymphoma, multilobated type. Histologic and immunohistochemical studies of the lymph node confirmed the presence of multilobated B-cell lymphoma. Lymphoma chemotherapy was initially successful but was discontinued due to toxicity. The patient died two months after the initial cytologic diagnosis of lymphoma. CONCLUSION: Multilobated lymphomas are an unusual variant of non-Hodgkin's lymphomas (mostly B-cell type). Cytology and immunocytochemistry are useful diagnostic procedures that can help to diagnose this relatively uncommon type of lymphoma and significantly reduce the possibility of misdiagnosis.

Aged↗
PubMedDate not supplied

Aortic atherosclerosis in pigs with heterozygous von Willebrand disease. Comparison with homozygous von Willebrand and normal pigs.

We have reported that pigs with severe homozygous von Willebrand disease (vWd) are resistant to spontaneous and high fat, high cholesterol, diet-induced atherosclerosis. In this study we report the quantitation of aortic atherosclerotic plaques in three groups of pigs fed with a high fat, high cholesterol (2%) diet from age 3 to 9 months. Nine normal pigs (normal factor VIII antigen, VIII R:AG, and ristocetin co-factor, VIII:RWF) had a mean of 21% atherosclerotic involvement of the distal aortic surface and a 4.5% mean involvement of the entire aorta. Five homozygous vWd pigs (undetected VIII R:AG and VIII:RWF) had a mean of 4.2% atherosclerotic involvement of the distal aortic surface and 1.2% involvement of the entire aorta (p less than 0.01, rank sum test). Five heterozygous vWd pigs (approximately 35% VIII R:AG and VIII:RWF) had a mean of 25% atherosclerotic involvement of the distal aortic surface and 6% involvement of the entire aorta; the results were not significantly different from those in the normal pigs. We concluded that resistance to atherosclerosis is not found in animals with moderate reduction of VIII R:AG and VIII:RWF. This may have implications for humans, since in human vWd both factors are almost always present.

Animals↗
PubMedDate not supplied

Effect of sulfinpyrazone on platelet survival time in patients with transient cerebral ischemic attacks.

Platelet suppressant drugs have been suggested as beneficial for patients with transient cerebral ischemic attacks and these drugs have been shown to lengthen shortened platelet survival time. In the present study platelet survival time (autologous labeling with 51Chromium) was measured in 25 patients with transient cerebral ischemia involving a carotid distribution. Platelet survival was shortened in all patients (2.5 +/- 0.10 days; AVE t 1/2 +/- SEM; Normal 3.7 +/- 0.04 days P less than 0.001). Sulfinpyrazone increased platelet survival in 9 of 19 (47%) of patients (2.4 +/- 0.10 to 2.8 +/- 0.16 days; P less than 0.01). Of the 19 treated with sulfinpyrazone, 10 had a marked reduction in the frequency of transient ischemic episodes and an increased in platelet survival (2.6 +/- 0.16 to 3.1 +/- 0.22 days; P less than 0.01) was observed in all patients. Three patients had no benefit from sulfinpyrazone and alteration of platelet survival did not occur. Results suggest that platelet survival is shortened in patients with transient cerebral ischemia, that sulfinpyrazone increases platelet curvival and may decrease the frequency of ischemic episodes, and that there may be a relationship between clinical benefit and alteration of platelet survival time.

Adult↗
PubMedDate not supplied

Adrenal cytomegaly: quantitative assessment by image analysis.

Adrenal cytomegaly was found in 23 or 0.8% of 2711 pediatric autopsies, including a 13-year-old girl with leukemia and a 20-year-old woman with cystic fibrosis. Cytomegaly of pancreatic islet and acinar cells and pituitary cells was also noted. DNA quantitation by image analysis indicates that cytomegalic cells of the adrenal cortex, pancreas, and pituitary contain increased amounts of DNA (hyperdiploid aneuploid), with adenocytes containing over 25 times the normal amount of DNA in some instances. These data and morphological features suggest that cytomegaly is a reflection of polyploidy due to either partial DNA replication or partial DNA replication plus other modes of polyploidization. Although the mechanism(s) by which these changes evolve remains unknown, regressive processes do not seem to be directly involved. We speculate that polyploidization is, in this setting, a response to physiological demand, a concept that also has relevance to the interpretation of morphology and DNA ploidy profiles of endocrine tumors.

Adolescent↗
PubMedDate not supplied

Evaluation of c-myc proto-oncogene in primary human breast carcinomas.

The expression of the c-myc proto-oncogene product was examined by immunohistochemistry in 11 normal breast tissues, 31 invasive and 14 non-invasive breast carcinomas. The c-myc product was detected in all breast carcinoma specimens and in seven of 11 normal breast tissues. Invasive tumors stained more frequently with the anti-myc monoclonal antibody (MAb) than non-invasive tumors, while the level of expression in normal breast tissue was much less than that in a breast cancer. Marked heterogeneity in the c-myc expression was seen among different tumors and within individual tumors. None of the eight invasive tumors with a high protein level of the c-myc showed evidence of gene amplification by Southern blot analysis.

Antibodies, Monoclonal↗
PubMedDate not supplied

Analysis of the c-myc and N-ras genes in acute myelogenous leukemia cells which manifest the constitutive expression of the c-myc gene.

The "constitutive" expression of the c-myc gene was detected in leukemia cells obtained from 4 patients with an acute myeloid leukemia, 3 with chronic myeloid leukemia and 1 with a myelodysplastic syndrome. Studies were undertaken to determine whether or not the myc gene was rearranged or mutated in exon I within a 3'Pvu II region, a transcriptional attenuation site. Studies to explore the possibility of a point mutation in the N-ras gene were also conducted. No abnormalities were detected in either gene. Studies should be undertaken evaluating the possibility of a post-transcriptional mechanism, such as alteration of RNA stability, which could be responsible for the constitutive expression of c-myc gene.

Acute Disease↗