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Biomedical subjects

A Markel

Publications and source records attributed to A Markel.

15 recordsLinked to original sources
PubMed1992

Pattern and distribution of thrombi in acute venous thrombosis.

The location and extent of thrombosis in the deep venous system will determine immediate and long-term outcome. During the past 3 years, we have studied by duplex scanning 833 patients with suspected deep vein thrombosis. In this group, 209 patients (25%) had a positive study. The findings relative to location and extent of involvement are as follows. (1) The right leg was involved in 35% of patients, the left leg in 48%. Bilateral involvement was noted in 17%. (2) The veins most frequently affected by deep vein thrombosis were as follows: superficial femoral in 74%, popliteal in 73%, common femoral in 58%, posterior tibial in 40%, deep femoral in 29%, greater saphenous in 19%, and the inferior vena cava in 2%; multisegment involvement was common. (3) Total occlusion was present in 82% of the patients with deep vein thrombosis, and partial occlusion in 18%. (4) Isolated occlusion of single veins was uncommon. (5) The proximal (above-knee) area was involved in 95% of the cases with deep vein thrombosis, and the calf in 40% of the cases. Isolated calf deep vein thrombosis was found in 6% of the cases with right leg involvement and in 3% for the left. (6) Total leg involvement (iliocaval, femoropopliteal, and calf) occurred in 10% of the patients. Our data confirm the fallibility of the clinical diagnosis of deep vein thrombosis. The frequent involvement of both limbs stresses the importance of not examining just the symptomatic limb. Proximal venous thrombosis (popliteal to inferior vena cava) is much more common than isolated calf vein thrombosis as a cause for symptoms and the referral for study.

Adolescent↗
PubMed1992

The potential role of thrombolytic therapy in venous thrombosis.

BACKGROUND: Anticoagulant therapy for lower extremity deep-vein thrombosis (DVT) has been shown to reduce mortality from pulmonary embolism, but subsequent morbidity from the postthrombotic syndrome remains high. Thrombolytic therapy produces higher lysis rates of venous thrombi than heparin alone. Some studies suggest a lower incidence of postthrombotic sequelae after early use of streptokinase. These potential benefits are limited to those patients without contraindications for this therapy. METHODS: For the past 3 years we have prospectively studied patients with DVT documented by duplex scanning. The records of these patients were reviewed to determine what proportion of this population would have been candidates for thrombolytic therapy. For this analysis, contraindications to the use of thrombolytic agents included: (1) recent surgery (less than 1 month); (2) recent major trauma; (3) active or recent bleeding; (4) brain disease (cerebrovascular accident, brain tumor, arteriovenous malformation); (5) pregnancy; and (6) bleeding diathesis. Also, patients with prior ipsilateral DVT and those with acute symptoms present for 7 or more days were not considered to be candidates for thrombolytic therapy. RESULTS: A contraindication to thrombolytic therapy was present in 194 (93%) of 209 patients with a diagnosis of DVT, including four patients with a relative contraindication. Two or more contraindications were present in 65 cases (31%). Recent surgery was the most frequent factor precluding therapy, being present in 71 patients. A history of DVT in the affected leg was present in 45 patients. CONCLUSIONS: Only 15 (7%) of 209 patients with DVT exhibited no contraindications for thrombolytic treatment. Only a small fraction of patients with venous thrombosis will be potential candidates for this therapy.

Adult↗
PubMed1992

Valvular reflux after deep vein thrombosis: incidence and time of occurrence.

From December 1986 to December 1990, 268 patients with acute deep vein thrombosis were studied in our laboratory. From this group 107 patients (123 legs with deep vein thrombosis) were placed in our long-term follow-up program. The documentation of valvular reflux and its site was demonstrated by duplex scanning. The duplex studies were done at intervals of 1 and 7 days, 1 month, every 3 months for the first year, and then yearly thereafter. The mean follow-up time for these patients was 341 days. In addition, reflux was evaluated in 502 patients with negative duplex study results and no previous history of deep vein thrombosis or chronic venous insufficiency. In the patients with acute deep vein thrombosis, valvular incompetence was noted in 17 limbs (14%) at the time of the initial study. Reflux was absent in 106 limbs (86%). In this last group reflux developed in 17% of the limbs by day 7. By the end of the first month, 37% demonstrated reflux. By the end of the first year, more than two thirds of the involved limbs had developed valvular incompetence. The distribution of reflux at the end of the first year of follow-up was the following: (1) popliteal vein, 58%; (2) superficial femoral vein, 37%; (3) greater saphenous vein, 25%; and (4) posterior tibial vein, 18%. Reflux seems to be more frequent in the segments previously affected with deep vein thrombosis. Among cases where segments were initially affected with thrombi, after 1 year the incidence of reflux was 53%, 44%, 59%, and 33% for the common femoral vein, superficial femoral, popliteal vein, and posterior tibial vein, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Late changes in veins after deep venous thrombosis: ultrasonographic findings.

In a prospective trial, 43 patients (45 legs) were re-examined by high resolution and continuous-wave Doppler ultrasonography 3-32 months after an acute episode of deep venous thrombosis (DVT). The veins were abnormal in 31 legs (69%). Abnormal veins were either narrowed with a highly echogenic lumen (thought to represent persistent occlusion) or with a relatively sonolucent lumen and thickened walls (thought to represent recanalized veins). Collateral veins were present. Some compression by probe could be achieved in partially occluded veins, but full collapsibility was absent. Continuous-wave Doppler studies were similar to those in acute DVT. In order to be able to diagnose new episodes of DVT in patients who have had DVT in the past, a baseline ultrasound study should be carried out approximately 6-12 months after an acute episode. In the absence of such a baseline study, contrast phlebography should be resorted to.

Collateral Circulation↗
PubMed1989

[Ultrasonographic diagnosis of deep vein thrombosis of the leg].

142 patients with the clinical diagnosis of deep vein thrombosis (DVT) of the legs were examined by high resolution ultrasound. The deep and superficial femoral and popliteal veins were examined with 6.5 and 10 MHz transducers. 124 of the patients were also examined with continuous wave Doppler ultrasound and in 46 contrast phlebography was performed. The overall accuracy of ultrasound compared to phlebography was 90%. If only the deep femoral vein was considered, ultrasound and phlebography correlated in 100%. The ultrasonographic characteristics of DVT are increased echogenicity of the involved vein, absence of response to the Valsalva maneuver and non-collapsibility of the thrombosed vein on pressing with the transducer probe. High resolution ultrasonography should be the primary tool for the diagnosis of DVT.

Humans↗
PubMed1989

The emergence of methicillin-resistant Staphylococcus aureus infections in an Israeli hospital.

Between July 1984 and August 1985, 200 cases of methicillin-resistant Staphylococcus aureus (MRSA) occurred in a large, tertiary care, medical school-affiliated hospital. During this period, a limited outbreak, causing serious infections, was identified in the Intensive Care Unit and was contained by appropriate infection control measures. Bacteriophage typing and surveillance cultures failed to identify a common or single source of dissemination of these strains. It appears that MRSA strains have emerged in Israel as endemic pathogens in hospitals, capable of causing serious nosocomial outbreaks.

Cross Infection↗
PubMed1988

High-resolution real-time ultrasonography in the diagnosis of deep vein thrombosis.

The contribution of high-resolution real-time ultrasonography to the diagnosis of deep vein thrombosis (DVT) was evaluated in a prospective study performed on 96 patients. 45 patients were also examined with contrast venography and 79 with continuous wave Doppler ultrasound. The femoral and popliteal veins were examined for compressibility by pressure with the transducer probe, response to deep inspiration and Valsalva's manoeuvre and presence of an intraluminal mass. The contralateral veins were routinely screened for comparison. The diagnostic sensitivity versus phlebography was 87%, and the specificity 100% for the femoral vein. When including the popliteal vein the specificity was 91%. Real-time ultrasonography together with Doppler ultrasound examination is an effective non-invasive approach for the diagnosis of DVT. Phlebography can be avoided if these two examinations are unequivocally positive or negative for DVT.

Humans↗
PubMed1988

Waterborne typhoid fever in Haifa, Israel: clinical, microbiologic, and therapeutic aspects of a major outbreak.

A major outbreak of waterborne typhoid fever involving 77 verified cases occurred in 1985 in a large suburban area of Haifa, Israel. The authors summarize the clinical, microbiologic, and therapeutic aspects of these patients. Fever, usually higher than 39 degrees C, was the hallmark of the disease. Other manifestations of typhoid, although relatively frequent, are presented as part of a mild nonspecific symptom complex, often found only in the prodromal period. An elevated level of serum glutamic-oxaloacetic transaminase (mean, 81 IU/ml) was the most characteristic laboratory abnormality, occurring in 94% of the patients. Blood cultures were positive in 46 of the 50 patients (92%), and were not affected by prior outpatient antibiotic therapy. The first blood culture was diagnostic in 93% of the cases. Although fever tended to disappear more rapidly among patients receiving ampicillin than among those treated with chloramphenicol, results of therapy were similar in both groups. Nevertheless, the relapse rate of 36% among 25 chloramphenicol-treated patients was significantly higher than the 9% noted among 22 patients treated with ampicillin. Except for one case of hemolytic anemia, serious complications were conspicuously absent, and outcomes were uniformly favorable.

Adolescent↗
PubMed1985

Increased plasma triglycerides, cholesterol and apolipoprotein E during prolonged fasting in normal subjects.

Plasma lipid and high density lipoprotein (HDL) levels were studied in 20 normal, healthy, non-obese males while fasting (150 kcal/d with free intake of water) for 6 d in a hunger strike. Plasma triglyceride and cholesterol levels were increased by 18% after 6 d of fasting. HDL-cholesterol concentration was not significantly changed for 4 d, but decreased by 22% after 6 d. Platelet aggregation induced by adenosine diphosphate (ADP) or collagen after 6 d of fasting was in the normal range. In 3 subjects fasted for 9 d, a complete plasma lipoprotein analysis was done. Very low and low density lipoprotein (VLDL and LDL) levels were elevated, whereas HDL was reduced after 9 d of fasting. On isoelectric focusing analysis, a marked reduction in apolipoprotein (apo) E concentration in both VLDL and HDL was noted. Liver function tests showed a reduction in hepatic enzyme activity; and since apo E is of hepatic origin also, we suggest that long fasting inhibits liver function in normal subjects.

Adult↗
PubMed1983

Increased platelet adhesion and aggregation in hypertensive patients: effect of atenolol.

Fourteen patients with established hypertension followed a double-blind crossover-styled trial to study the effects of 100 mg/day atenolol compared to placebo. Atenolol was found to be an effective antihypertensive agent, reducing both systolic and diastolic blood pressure. Hypertensive patients appear to have increased in vitro platelet adhesion and aggregation. Atenolol significantly reduced platelet adhesion, but had little effect on aggregation. This may be important in contributing towards the now-recognised cardio-protective effect of the beta-adrenoceptor blocking agents. Blood chemistry and haematological parameters were unchanged; but whereas plasma cholesterol and plasma triglyceride levels remained normal, there was a significant fall in plasma high-density lipoprotein cholesterol levels. Side effects were very few.

Adult↗