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Biomedical subjects

G Amir

Publications and source records attributed to G Amir.

At least 37 records · Page 2Linked to original sources
PubMed1998

Effect of moderate bone hyperthermia on cell viability and mechanical function.

Extracorporeal hyperthermia treatment of bone followed by its reimplantation may be an optional treatment of bone tumors. In this study, the authors examined the minimal hyperthermic condition in which complete eradication of all viable cells in rat bone can be achieved and the mechanical effect of this treatment on the tested bone. When the results were evaluated histologically by special lactate dehydrogenase activity staining, it was found that complete bone cell death occurred after 30 minutes of heating at 60 degrees C. Cartilage cells, including those of the epiphysis, were more resistant to thermal damage. When the ability of the specimens to proliferate in cell cultures was tested, no growth was observed after heating at temperatures of 50 degrees C or greater. The mechanical stiffness tested in the Instron machine showed decreased bone stiffness at 70 degrees C but no change in the breaking load of the bones. Controlled hyperthermia's ability to eradicate viable cells without significant damage to the mechanical properties may have clinical relevance in limb salvage tumor surgery.

Animals↗
PubMed1997

Predictors of early and overall outcome in coronary artery bypass without cardiopulmonary bypass.

OBJECTIVE: Cardiopulmonary bypass in coronary artery bypass graft operations may adversely affect the outcome especially in high-risk patients. The purpose of this study is to evaluate results of coronary artery bypass performed without cardiopulmonary bypass, in a relatively high-risk cohort, and to identify predictors of unfavorable outcome. METHOD: Three hundred and thirteen (313) patients, 246 (79%) of whom had high-risk conditions, who have a coronary anatomy suitable for coronary artery bypass surgery without cardiopulmonary bypass, underwent this procedure between December 1991 and July 1995. Mean number of grafts/patient was 1.8 (1-5), and only 71 patients (23%) received a graft to the circumflex coronary system. RESULTS: Early unfavorable outcome events included operative mortality (12 patients, 3.8%), nonfatal perioperative myocardial infarction (eight patients, 2.6%), emergency reoperation (three patients, 0.9%), sternal infection (five patients, 1.6%), and nonfatal stroke (two patients, 0.6%). Multivariate analysis revealed angina pectoris class IV (odds ratio 5.4) and age > or = 70 years (odds ratio 5.0) as independent predictors of early mortality. Preoperative risk factors such as repeat coronary artery bypass grafting (50 patients, 16%), ejection fraction < or = 0.35 (85 patients, 27%), acute myocardial infarction (86 patients, 28%), cardiogenic shock (ten patients, 3.2%), chronic renal failure (25 patients, 8%), chronic obstructive pulmonary disease (20 patients, 6%), and peripheral vascular disease (51 patients, 16%) did not increase early mortality. During 33 months of follow-up (range 1-57 months), there were 42 deaths, at least 16 cardiac-related (one and four years actuarial survival of 90% and 76% respectively), and 39 patients (12.5%) in whom angina returned. Calcified aorta (odds ratio 2.6) and old myocardial infarction (odds ratio 1.8) were independent predictors of overall unfavorable events. CONCLUSIONS: Coronary artery bypass grafting without cardiopulmonary bypass can be performed with relatively low operative mortality in certain high-risk subgroups of patients; however, an increased risk of graft occlusion is a potential disadvantage. This procedure should therefore be considered only for patients with suitable coronary anatomy, in whom cardiopulmonary bypass poses a high risk. Although the risk of stroke is relatively low, the procedure is still hazardous for patients aged 70 years and over.

Adult↗
PubMed1997

Primary non-Hodgkin's lymphoma of the lung presenting as bronchiolitis obliterans organizing pneumonia.

A 44-year-old man presented with fever, dyspnea, and bilateral cavitary lung lesions. Following percutaneous transthoracic CT guided needle biopsy of the lung, a diagnosis of bronchiolitis obliterans organizing pneumonia (BOOP) was made and the patient was treated with corticosteroids. Despite a good initial response he developed new lung lesions within six months, associated with a lack of response to corticosteroids. Due to further deterioration and the development of Guillian-Barre' syndrome an open lung biopsy was performed and revealed T-cell rich, B-cell non Hodgkin's lymphoma with BOOP. We suggest that BOOP may be the presenting manifestation of primary lung lymphoma. We recommend that when BOOP has an atypical course or does not respond to corticosteroids open lung biopsy should be performed in order to exclude pulmonary lymphoma.

Adult↗
PubMed1997

The founder mutations 185delAG and 5382insC in BRCA1 and 6174delT in BRCA2 appear in 60% of ovarian cancer and 30% of early-onset breast cancer patients among Ashkenazi women.

The mutations 185delAG, 188del11, and 5382insC in the BRCA1 gene and 6174delT in the BRCA2 gene were analyzed in 199 Ashkenazi and 44 non-Ashkenazi Jewish unrelated patients with breast and/or ovarian cancer. Of the Jewish Ashkenazi women with ovarian cancer, 62% (13/21) had one of the target mutations, as did 30% (13/43) of women with breast cancer alone diagnosed before the age 40 years and 10% (15/141) of those with breast cancer diagnosed after the age 40 years. Age at ovarian cancer diagnosis was not associated with carrier status. Of 99 Ashkenazi patients with no family history of breast and/or ovarian cancer, 10% carried one of the mutations; in two of them the mutation was proved to be paternally transmitted. One non-Ashkenazi Jewish ovarian cancer patient from Iraq carried the 185delAG mutation. Individual mutation frequencies among breast cancer Ashkenazi patients were 6.7% for 185delAG, 2.2% for 5382insC, and 4.5% for 6174delT, among ovarian cancer patients; 185delAG and 6174delT were about equally common (33% and 29%, respectively), but no ovarian cancer patient carried the 5382insC. More mutations responsible for inherited breast and ovarian cancer probably remain to be found in this population, since 79% of high-incidence breast cancer families and 35% of high-incidence breast/ovarian cancer families had none of the three known founder mutations.

Adult↗
PubMed1996

[Leukocytoclastic vasculitis associated with naproxen].

We describe a 62-year-old woman who developed severe, cutaneous, leukocytoclastic vasculitis following administration of Naproxen. Nonsteroidal anti-inflammatory drugs are widely used by millions for their analgetic as well as anti-inflammatory effects. While side-effects involving the kidney and the gastrointestinal tract are well known, hypersensitivity vasculitis is rarely reported. We report an additional case.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1996

Renal vasoactive mediator generation in portal hypertensive and bile duct ligated rats.

BACKGROUND/METHODS: Vasoactive substances may have a role in the pathogenesis of functional renal abnormalities in patients with cirrhosis. We determined renal vasoactive mediators in rats with portal hypertension since the balance in each part of the kidney between the vasodilator activity of prostaglandin E2 and the vasospastic activity of thromboxane A2, leukotriene B4, leukotriene C4, endothelin-1 and platelet activating factor may determine renal function. Rats with partial portal vein ligation (n = 7), complete bile duct ligation (n = 6) and sham operated (n = 10) were studied. Three weeks following surgery renal function tests, including fractional excretion of sodium [Fe(Na)] were measured. Rats were anesthetized, splenic pulp pressure was measured, kidneys were removed, and cortex, medulla and papilla were separated and homogenized for determination of prostaglandin E2, thromboxane B2, leukotriene B4, leukotriene C4 and endothelin-1 by radioimmunoassay (ng/g) and platelet activating factor activity (pg/10 mg) by platelet aggregation. RESULTS: Pulp pressure was > 13 mmHg in portal vein ligated and bile duct ligated and 6 mmHg in sham operated rats. In bile duct ligated rats there was a 70% decrease in Fe(Na) and a significant decrease in cortical and papillary prostaglandin E2, whereas cortical thromboxane B2 and platelet activating factor activity in the cortex, medulla and papilla were double that of sham operated rats. A similar but insignificant trend of changes was found in portal vein ligated rats. Medullary leukotriene B4 was significantly decreased in bile duct ligated rats. Papillary leukotriene B4 was not detected in bile duct ligated and portal vein ligated rats. Renal leukotriene C4 generation in the three groups was either unchanged (papilla) or beyond detection (cortex and medulla). Medullary and papillary endothelin-1 in portal vein ligated and bile duct ligated rats were 178%-130% higher than in sham operated rats. A significant negative correlation was found between Fe(Na) and cortical and medullary thromboxane B2 generation and medullary platelet activating factor activity. CONCLUSIONS: 1) In bile duct ligated rats enhanced intrarenal generation of thromboxane A2 and platelet activating factor may contribute to decreased renal sodium excretion. 2) The role of decreased intrarenal prostaglandin E2 and increased intrarenal endothelin-1 content in bile duct ligated rats is not yet understood. 3) Renal leukotriene generation is either decreased or undetected in portal vein ligated and bile duct ligated rats.

Animals↗
PubMed1996

Kaposi's sarcoma on a lymphedematous arm after mastectomy.

Two patients with Kaposi's sarcoma developing in an area of lymphedematous arm postmastectomy are reported. The Kaposi's sarcoma occurred after latent periods of 26 and 7 years following radical and modified-radical mastectomy, respectively, in the edematous tissue of the ipsilateral arm. The cutaneous nodules were purple in color and ranged in size from a few millimeters to > 1 cm in diameter. The results of routine laboratory tests were all within normal limits. Human immunodeficiency virus (HIV) antibody and cytomegalovirus (CMV) antigen, using enzyme-linked immunosorbent assay (ELISA), were negative.

Aged↗
PubMed1996

Gastric and colonic inflammatory and vasoactive mediators in experimental portal hypertension.

Rats with portal hypertension and experimental liver disease may exhibit increased susceptibility of the gastric mucosa to damage by noxious agents, and increased bacterial translocation through the bowel wall. The aim of this study was to determine mucosal gastric and colonic generation of vasoactive substances, because they may contribute to the altered mucosal function. Rats with partial vein ligation (n = 7), complete bile duct ligation (n = 6) and sham-operated rats (n = 10) were studied. Three weeks following surgery rats were anesthetized, splenic pulp pressure was measured, stomachs and colons were removed and mucosa was extracted for determination of prostaglandin E2, thromboxane B2, leukotriene B4, leukotriene C4 and endothelin-1 by radioimmunoassay (ng/g) and platelet activating factor activity (pg/10 mg) by platelet aggregation. Pulp pressure was > 13 mmHg in partial vein ligated rats and bile duct ligated rats and 6 mmHg in sham-operated rats. No macroscopic or microscopic lesions were seen any of the removed tissues. Gastric mucosal prostaglandin E2 and thromboxane B2 generation were decreased by 35% and 7%, respectively, in bile duct ligated rats (bile duct ligated versus sham-operated, p < 0.05 for prostaglandin E2 and thromboxane B2). Gastric leukotriene B4 and C4 generation, platelet activating factor activity and endothelin-1 content did not differ significantly among the three groups. A different pattern of changes was observed in the colon. Colonic leukotriene B4 generation and endothelin-1 content were increased in bile duct ligated rats by 105% and 210%, respectively (bile duct ligated versus sham-operated, p < 0.05 for leukotriene B4 and endothelin-1). The decreased gastric mucosal prostaglandin E2 generation of bile duct ligated rats may render the gut mucosa of these animals relatively ischemic and vulnerable to damage by noxious agents. The increased colonic leukotriene B4 generation and the increased endothelin-1 content of the colonic mucosa of bile duct ligated rats may promote inflammatory and ischemic changes in the colonic mucosa and may enable bacterial translocation.

Animals↗
PubMed1995

Histomorphometric analysis of innervation of the anterior cruciate ligament in osteoarthritis.

The aim of this study was to determine whether there are quantitative changes in the innervation of the anterior cruciate ligament in osteoarthritis. Eleven whole anterior cruciate ligaments were obtained at autopsy from cadavera of individuals with advanced osteoarthritis: five healthy ligaments were used as controls. The ligaments were transected and stained with hematoxylin and eosin, oil red O for fat, and a modification of Gairn's gold chloride method. The latter stain permits visualization of axons, mechanoreceptors, and free nerve endings that are not apparent on routine stains. The ratio of nerve tissue to periligamentous synovial tissue was determined histomorphometrically by the point-counting method. The nerve tissue was located almost exclusively in the periligamentous synovial tissue. There was a statistically significantly greater area of nerve tissue (as a percentage of the total area) around the anterior cruciate ligaments in the osteoarthritic group than around the ligaments in the control group (p < 0.02). The nerve tissue was distributed evenly throughout the periligamentous synovial tissue in the specimens in both groups. A neurological role has been proposed for the anterior cruciate ligament in osteoarthritis. This study provides morphological evidence for neural pathology of the anterior cruciate ligament in subjects with osteoarthritis.

Adipose Tissue↗
PubMed1995

Acquired glomerulocystic kidney disease following haemolytic-uraemic syndrome.

Glomerulocystic kidney disease is a rare condition, usually seen in infants and young children, characterised by cystic dilatation of the glomeruli. It may be sporadic or represent the congenital expression of dominant polycystic kidney disease. Glomerular cysts may also be seen in association with various syndromes and as a component of dysplastic kidneys. Only two cases of acquired glomerulocystic kidneys have been described, both in adults. The cystic change followed haemolytic-uraemic syndrome in one patient and systemic sclerosis in the other. These two conditions are closely related and may be indistinguishable pathologically. We report a case of acquired glomerulocystic kidney in a child which followed the haemolytic-uraemic syndrome. The factors leading to glomerulocystic kidney following haemolytic-uraemic syndrome are unknown and need further evaluation.

Adolescent↗
PubMed1995

Clear cell chondrosarcoma of rib following repetitive low-impact trauma.

A case of clear cell chondrosarcoma of the rib in a 30-year-old man is described. The tumor developed at the site of repetitive low-impact trauma (on the arm of a wheelchair) over a period of 24 years. An association between chondrosarcoma and external trauma has not been previously reported. Chondrosarcoma has been described in previously irradiated bone and in Paget's disease. In both these examples there is an increase in new bone formation associated with necrosis of bone and increased resorption of bone, respectively. A possible mechanism in our case is increased new bone formation elicited by repeated microfractures of trabeculae of rib bone.

Adult↗
PubMed1994

[Percutaneous, CT-guided excision of femoral osteoid osteoma].

An osteoid osteoma in the distal femur of a 10-year-old girl was excised, percutaneously, under CT guidance. Location of the nidus was by insertion of a Kirshner wire under CT control. Hollow Mill was used to excise the nidus by drilling over the Kirshner wire, with CT guidance during each stage. There were no complications and pain ceased overnight. Follow-up after 4 months showed complete recovery and no pain.

Child↗
PubMed1994

Studies on the etiology of acute acalculous cholecystitis: the effect of lipopolysaccharide on human gallbladder mucosal cells.

Previous studies in animals have shown that lipopolysaccharide produces experimental cholecystitis possibly through a platelet-activating factor-prostanoid mediated process. In this study it was intended to evaluate the effect of LPS on primary cultures of human gallbladder mucosal cells. Gallbladder mucosal cells were isolated from gallbladders removed during routine cholecystectomies or other operations. The cells were cultured for 24 h before treatment. Unstimulated cells produced low levels of prostanoids and significant basal levels of PAF. LPS produced stimulation of eicosanoid and PAF secretion. The increased prostanoid formation was not enhanced when LPS and PAF were administered together. Prostanoid synthesis was inhibited by the administration of a cyclooxygenase inhibitor while administration of a PAF receptor antagonist significantly increased prostanoid formation, suggesting that increased PAF levels function as a negative control mechanism to decrease prostanoid synthesis. The results suggest that endotoxemia may produce a cascade of inflammatory processes in human gallbladder mucosal cells resulting in the development of acute acalculous cholecystitis.

Acute Disease↗
PubMed1994

Dermatomyositis associated with Crohn's disease.

A 29-year-old woman with quiescent Crohn's disease developed severe myositis. Serum creatine phosphokinase was markedly elevated, and muscle biopsy showed typical findings of dermatomyositis. The muscular symptoms promptly responded to combined treatment with corticosteroids and azathioprine. The association between inflammatory bowel disease and inflammatory myopathies is very rare. We review the clinical, pathological, and pathophysiological aspects of this association.

Adult↗
PubMed1994

Enhanced gastric nitric oxide synthase activity in duodenal ulcer patients.

Nitric oxide, the product of nitric oxide synthase in inflammatory cells, may have a role in tissue injury through its oxidative metabolism. Nitric oxide may have a role in the pathogenesis of duodenal ulcer and may be one of the mechanisms responsible for the association between gastric infection with Helicobacter pylori and peptic disease. In this study, calcium independent nitric oxide synthase activity was detected in human gastric mucosa suggesting expression of the inducible isoform. In 17 duodenal ulcer patients gastric antral and fundic nitric oxide synthase activity was found to be two and 1.5-fold respectively higher than its activity in the antrum and fundus of 14 normal subjects (p < 0.05). H pylori was detected in the antrum of 15 of 17 duodenal ulcer patients and only in 7 of 14 of the control subjects. Antral nitric oxide synthase activity in H pylori positive duodenal ulcer patients was twofold higher than in H pylori positive normal subjects (p < 0.05). In duodenal ulcer patients antral and fundic nitric oxide synthase activity resumed normal values after induction of ulcer healing with ranitidine. Eradication of H pylori did not further affect gastric nitric oxide synthase activity. These findings suggest that in duodenal ulcer patients stimulated gastric mucosal nitric oxide synthase activity, though independent of the H pylori state, may contribute to the pathogenesis of the disease.

Acute Disease↗