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Biomedical subjects

S H Silverman

Publications and source records attributed to S H Silverman.

At least 19 recordsLinked to original sources
PubMed2006

Obesity and thrombosis.

OBJECTIVES: To describe the pathophysiological mechanisms by which obesity increases the propensity to thrombosis, the leading cause of death in the Western World, with particular emphasis on the role of inflammation, oxidative stress, dyslipidaemia, insulin resistance and the coagulation cascade. DESIGN: Review article. MATERIALS AND METHODS: Medline (1966-2005) and Cochrane library review of literature examining the relationship between obesity and thrombosis. Search terms included obesity, overweight, body mass index, thrombosis, cardiovascular disease, venous thromboembolism, peripheral arterial disease, and coronary heart disease. RESULTS: Obesity is an important and growing public health issue that is estimated to affect more than half of the UK adult population. Obesity, in particular central (visceral) obesity, is associated with significant, and largely preventable, morbidity and mortality including an increased incidence and prevalence of arterial and venous thrombotic events. The various mechanisms by which obesity may cause thrombosis include: the actions of so-called adipocytokines from adipose tissue, e.g. leptin and adiponectin; increased activity of the coagulation cascade and decreased activity of the fibrinolytic cascade; increased inflammation; increased oxidative stress and endothelial dysfunction; and disturbances of lipids and glucose tolerance in association with the metabolic syndrome. CONCLUSIONS: Obesity appears to be associated with thrombosis via several mechanisms. These pro-thrombotic factors are all improved by weight loss.

Adiponectin↗
PubMed2002

Ethnicity and peripheral vascular disease.

There are well-documented differences in the prevalence of coronary artery disease and carotid disease between caucasians, Afro-Caribbeans and Indo-Asians. Very little data are available on ethnic differences in peripheral vascular disease (PVD). To investigate this further, we surveyed 200 consecutive patients attending the vascular surgery service at a city centre hospital serving a multiethnic patient catchment population. All patients had proven PVD, with an ankle brachial pressure index of less than 0.8. Within this cohort, Afro-Caribbeans presented more frequently with PVD compared with the proportion of this ethnic group in the local population (p = 0.013), with a greater proportion with diabetes mellitus than in the other two ethnic groups. There did not appear to be a significant difference between the ethnic groups in any of the other established risk factors or associations (i.e. treated hypertension, smoking, previous history of ischaemic heart disease, atrial fibrillation, previous history of cerebrovascular accident or transient ischaemic attack) with PVD. As with coronary artery disease and carotid disease, there are ethnic differences in the prevalence of PVD, and the underlying risk factors, between caucasians, Afro-Caribbeans and Indo-Asians. Furthermore, patients of Afro-Caribbean origin present more frequently with symptomatic PVD than do either caucasians or Indo-Asians.

Aged↗
PubMed1998

Critical lower limb ischaemia following excision of the rectum.

Critical lower limb ischaemia can occur following rectal surgery by a number of mechanisms. Patients with aorto-iliac stenosis or occlusion may be dependent on collateral circulation to the lower limbs from the visceral arteries supplying the descending colon, sigmoid colon and the rectum. Division of these collaterals can precipitate critical ischaemia of the leg. This is an uncommon scenario but one that should be considered in arteriopaths undergoing rectal surgery. Two cases of this complication are reported and the mechanisms discussed.

Aged↗
PubMed1998

The setting up and implementation of a venous thromboembolism prophylaxis policy in clinical hospital practice.

Clinical management policies are meant to lead to the delivery of better health care. However, as we demonstrate in this review, having an oral or written venous thromboembolism prophylaxis policy does not necessarily lead to the majority of general surgical inpatients receiving the appropriate prophylaxis. We discovered, through prospective clinical audit, that for a clinical policy to be effective in delivering the appropriate health care, it must be repeatedly scrutinized and implemented in the correct manner. Only after several rounds of the audit cycle were we able to achieve the deliverance of venous thromboembolism prophylaxis to the majority of general surgical patients on our unit. This has wider implications, not just for the implementation of a venous thromboembolism prophylaxis policy, but also for all clinical management policies, and illustrates the importance of clinical audit in clinical practice.

Guideline Adherence↗
PubMed1993

The case for formal stratification analysis when prescribing deep vein thrombosis prophylaxis.

Postoperative deep vein thrombosis (DVT) is common following general and orthopaedic surgery. Certain factors are known to increase the risk of DVT. To ascertain how surgeons use these factors to assess DVT risk and modify their DVT prophylaxis for individual cases, we circulated a questionnaire to 100 general and 200 orthopaedic surgeons. We inquired about whether DVT prophylaxis was used, and what risk factors were recognized, and we asked the surgeons to ascribe a level of DVT risk for five imaginary cases. All surgeons claimed to use prophylaxis. Most surgeons were largely aware of the accepted risk factors. There was, however, no consensus in allocating level of risk to individual imaginary cases. In conclusion, in spite of being aware of risk factors, similar patients are being dealt with in widely different ways by different clinicians. Therefore, we feel it is important to formally assess each individual patient's DVT risk and prescribe prophylaxis accordingly.

Adult↗
PubMed1991

Intraarterial drug abuse: new treatment options.

Accidental, intraarterial injections of abused substances continue to be difficult management problems because of severe vascular complications. Vasospasm probably plays an important role in the pathophysiology of this injury, in addition to the more accepted roles of thrombosis and endarteritis. Three patients with severe, upper extremity ischemia after intraarterial injection of heroin, methamphetamine, and meperidine were treated with intraarterial tolazoline and streptokinase, along with intravenous heparin. All three patients had improved perfusion, assessed both clinically and by angiography. The responses to treatment in these patients demonstrated the roles of vasospasm and thrombosis in the origin of this injury and the therapeutic benefits of appropriately administered vasodilators and thrombolytic agents.

Adult↗
PubMed1991

Rat model of chronic lung infections caused by non-typable Haemophilus influenzae.

Patients with chronic obstructive pulmonary disease (COPD) often have chronic or recurrent pulmonary infections with non-typable Haemophilus influenzae. A model of these infections exploited agar bead vehicles to protect the inoculum from rapid clearance, and a chronic lung infection of at least 42 days duration was established in rats. This infection induced increases in serum IgG titres to outer-membrane (OM) and lipo-oligosaccharide (LOS) antigens; immunoblotting demonstrated that this humoral response was directed partly against the outer-membrane proteins (OMPs). Lung lavage fluid also contained an increased titre of IgG antibodies to OM and LOS 42 days after infection. Antibodies produced during infection with one strain of H. influenzae cross-reacted with OMPs from another, non-typable H. influenzae strain. Despite their encasement in agar beads, pulmonary H. influenzae remained susceptible to amoxycillin. This model of chronic pulmonary infections due to non-typable H. influenzae appears to resemble the situation in COPD patients and may be useful for experimental therapeutic studies.

Animals↗
PubMed1989

Effect of CO2 and blood media on laser probe temperature.

Blood may limit laser ablation of arterial plaque by decreasing thermal energy transfer from metal-capped probes to arterial occlusions. Since a gas is a good insulator of heat, CO2 may be a better medium for laser recanalization. To study this possibility, a metal-capped fiber was positioned in a segment of blood-filled polyethylene tubing and activated with an argon laser. Probe temperatures were measured in blood and as the blood was displaced by flowing CO2 gas. Probe temperatures were higher at all powers studied in CO2 gas than in blood. Maximum probe temperatures averaged 518 +/- 24 degrees C after CO2 infusion versus 320 +/- 7 degrees C in blood, (P less than 0.0001). Blood aggregate formation was noted on the probe surface in blood but not in CO2 medium. Thus CO2 gas may be a preferable medium for laser recanalization, since higher probe temperatures are achieved, and the probe surface remains free of insulating blood coagulate.

Angioplasty, Balloon↗
PubMed1989

The fecal microflora in pruritus ani.

Pruritus ani is a common condition in which there is a tendency for liquids to leak from the anal canal, resulting in perianal soiling. In order to ascertain if an abnormal fecal flora contributes to the irritant effects of fecal material, qualitative and quantitative measurement of the fecal microflora was performed in 20 patients with pruritus ani and 20 matched controls. No differences were found between the two groups. This study has failed to provide evidence for a microbiologic basis for pruritus ani.

Adult↗
PubMed1989

Initial results of laser recanalization in lower extremity arterial reconstruction.

One hundred ninety-five patients have been evaluated for possible laser recanalization (LR). Current laser delivery systems are most appropriate for the treatment of superficial femoral, popliteal, or isolated common iliac artery occlusions, and therefore one half (110) of the patients were initially excluded because of inappropriate disease location. An additional 39 patients were excluded because they showed minimal symptoms or the procedure would have been excessively risky for them. The remaining 46 patients underwent LR for total arterial occlusions, with relief of symptoms and increased ankle brachial indexes in 22 (48%). Of the four patients who could not be surgically reconstructed because of tibial artery occlusion, none was successfully treated. Only one patient required emergency reconstruction for ischemia after LR failure, and no procedures were required for treatment of perforation or bleeding. Successful LR was most likely when isolated lesions less than 15 cm in length, in the common iliac, middle or distal superficial femoral, and above-knee popliteal arteries were treated. Of the 22 patients for whom LR was successful, 11 would have been candidates for standard surgical therapy, six would have been excluded from such therapy by medical or surgical risks, and five had symptoms usually considered too mild to be offered surgery. Thus, at present the impact of LR on the treatment of patients with peripheral vascular disease appears limited.

Angiography↗