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Biomedical subjects

H Salem

Publications and source records attributed to H Salem.

At least 19 recordsLinked to original sources
PubMed2000

Intratracheal instillation as an exposure technique for the evaluation of respiratory tract toxicity: uses and limitations.

The evaluation of respiratory tract toxicity from airborne materials frequently involves exposure of animals via inhalation. This provides a natural route of entry into the host and, as such, is the preferred method for the introduction of toxicants into the lungs. However, for various reasons, this technique cannot always be used, and the direct instillation of a test material into the lungs via the trachea has been employed in many studies as an alternative exposure procedure. Intratracheal instillation has become sufficiently widely used that the Inhalation Specialty Section of the Society of Toxicology elected to develop this document to summarize some key issues concerning the use of this exposure procedure. Although there are distinct differences in the distribution, clearance, and retention of materials when administered by instillation compared to inhalation, the former can be a useful and cost-effective procedure for addressing specific questions regarding the respiratory toxicity of chemicals, as long as certain caveats are clearly understood and certain guidelines are carefully followed.

Aerosols↗
PubMed1998

Relationships between protein C, protein S, von Willebrand factor and euglobulin lysis time and cardiovascular risk factors in subjects with and without coronary heart disease.

Measures of fibrinolytic and thrombotic function have been examined in 55 subjects with recently identified coronary heart disease, and age and sex matched control subjects. Measurements were particularly directed at factors and processes which could be affected by changes in endothelial function and included the euglobulin lysis time as well as plasma levels of von Willebrand factor (vWF). Plasma levels of protein S and protein C were also measured. Measurements were made before and after a period of 10-min veno-occlusion combined with rhythmic hand exercise. In addition anthropometric, haemodynamic and biochemical measurements (plasma lipids and apolipoproteins, glucose and insulin) were obtained and correlated with the haematological parameters. Protein S and vWF levels were significantly higher, both before and after veno-occlusive exercise, in subjects with CHD than in the asymptomatic controls. Euglobulin lysis times were not significantly different but only shortened on veno-occlusive exercise in those without CHD. Protein S levels were significantly correlated with systolic blood pressure, plasma total cholesterol, plasma triglyceride, plasma phospholipid, plasma fasting glucose and both apolipoprotein A1 and B levels. vWF levels were not significantly related to any of the other variables. Subjects whose pre-exercise euglobulin lysis times exceeded 6 h had significantly higher BMI, plasma total cholesterol, triglyceride, phospholipid, insulin, glucose and apoB concentrations and lower HDL cholesterol than those with lysis in less than 6 h. The findings from this study are consistent with a role for endothelial dysfunction in the production of atherosclerotic vascular disease and may indicate additional, non-haemodynamic, mechanisms for such an association. In addition, the relationship between elevated levels of protein S and CHD does not appear to depend on the demonstrated associations between protein S and a number of other cardiovascular risk factors.

Aged↗
PubMed1998

Medication use in home care patients with COPD.

Chronic obstructive pulmonary disease (COPD) is the fourth-leading cause of death in the United States. Although many other diseases have seen a gradual decline in their associated mortality, COPD rates have increased nearly 33% from 1979 to 1991. The disease is defined as a slowly progressive obstruction of airflow that is predominantly irreversible. COPD usually begins in the fifth decade of life as an increased cough. Dyspnea on exertion is frequently observed in the sixth or seventh decade.

Adrenergic beta-Agonists↗
PubMed1997

Testicular sperm extraction and intracytoplasmic sperm injection: a simplified method for treatment of obstructive azoospermia.

OBJECTIVE: To assess the effectiveness of a simple method of testicular sperm extraction for the treatment of obstructive azoospermia. DESIGN: Retrospective study. SETTING: Teaching tertiary medical center. PATIENT(S): Seventeen men with obstructive azoospermia. INTERVENTION(S): The patients underwent 19 cycles of intracytoplasmic sperm injection (ICSI) using testicular sperm. In 5 cycles, testicular sperm extraction was performed after failed microepididymal sperm aspiration. In 14 cycles, testicular sperm extraction was performed in the office under local anesthesia from the outset. The outcome was compared with ICSI cycles using ejaculated sperm (95 cycles) and epididymal sperm (12 cycles fresh and 9 cycles frozen-thawed). MAIN OUTCOME MEASURE(S): Clinical pregnancy and implantation rates. RESULT(S): There were no differences in the fertilization, cleavage, implantation, or clinical pregnancy rates among ICSI cycles using testicular, epididymal (fresh or frozen-thawed), or ejaculated sperm. CONCLUSION(S): When used in conjunction with ICSI, testicular sperm extraction from small excisional biopsy is a simple and cost-effective method for the treatment of obstructive azoospermia.

Embryo Implantation↗
PubMed1996

Raised circulating levels of interleukin-6 in women with an intrauterine contraceptive device.

The aim of this study was to determine whether the presence of an intrauterine contraceptive device (IUCD) causes a systemic elevation of interleukin-6 (IL-6). The control group comprised 29 women with normal cycles and who were not using any form of contraception and the study group comprised 74 women who had had an IUCD in place for 10-24 months. Of these, 45 had intermenstrual bleeding. Systemic IL-6 was undetectable (minimum detection limit of the assay is 5 pg/ml) in the control but was raised in 20% of the women fitted with an IUCD (p < 0.01). There was no difference between IL-6 levels in IUCD users who had intermenstrual bleeding and those who did not. These results suggest that the effects of chronic IUCD usage may not be limited to the endometrium.

Adult↗
PubMed1994

VQLM: a Visual Query Language for Macromolecular structural databases.

Databases of macromolecular structures allow researchers to identify general principles of molecular behavior. They do this by providing a variety of data obtained under a number of different experimental conditions. Many new tools have been developed recently to aid in exploratory analysis of structural data. However, some queries of interest still require considerable manual filtering of data. In particular, studies attempting to make generalizations about complex arrangements of atoms or building blocks in macromolecular structures cannot be approached directly with existing tools. Such studies are frequently carried out on only a few structures or else require a labor-intensive process. To address this problem, we have developed a visual language, VQLM (Visual Query Language for Macromolecules). A query is formulated in this language by drawing an abstract picture of substructures to be searched for in the database and specifying constraints on the objects in them. To illustrate the usefulness of our language, we show how to encode a number of queries that were found scientifically interesting in the published literature in molecular biology. VQLM relies on VQL, a new database language, as its underlying engine for database retrieval and computation. We believe that VQLM will make macromolecular structural data more accessible to scientists, enabling faster and deeper data analysis.

Animals↗
PubMed1992

Autoantibodies to thrombomodulin: development of an enzyme immunoassay and a survey of their frequency in patients with the lupus anticoagulant.

In order to investigate the possibility that autoantibodies to thrombomodulin (TM) may exist in patients with the lupus anticoagulant (LA) and perhaps be implicated in the pathogenesis of recurrent thrombosis seen in such patients, we developed an enzyme-immunoassay to screen serum samples for anti-human TM activity. The major technical problem encountered in developing this assay was to reduce the non-specific binding of serum components from both the LA positive and the negative population. Considerable reduction of non-specific binding was achieved by use of a phosphate/citrate buffer at pH 8.0 and the use of an optimal sample dilution of 1/40. In addition, samples were always tested in parallel in blank wells and results are expressed as an OD ratio. Samples from 113 patients with the LA were assayed and compared to 78 patients referred for LA testing but found to be negative. The mean OD values for the LA positive patients (+/- SD) was 1.36 (0.44) with a range of 0.78-2.57. This was virtually identical to the values for the LA negative population (1.38 +/- 0.40, range 0.76-2.77). The results of this study indicate that there is no evidence for the presence of a significant autoantibody activity to TM in patients with the LA when compared to LA negative patients. If such autoantibodies do exist their frequency must be quite low.

Autoantibodies↗
PubMed1992

Tumor necrosis factor production during human renal allograft rejection is associated with depression of plasma protein C and free protein S levels and decreased intragraft thrombomodulin expression.

Fibrin deposition is a common accompaniment of renal allograft rejection, indicating disruption of the normal physiologic balance between procoagulant and anticoagulant pathways. In vitro, tumor necrosis factor (TNF) induces endothelial expression of the procoagulant, tissue factor, and downregulation of thrombomodulin, a key component of the thrombomodulin/protein C (PC)/protein S (PS) pathway, which normally maintains an anticoagulant state by inactivating thrombin, preventing further thrombin formation by degrading factors Va and VIIIa, and decreasing plasminogen activator inhibitor activity. Raised levels of TNF were recently demonstrated within the blood of patients during episodes of renal allograft injection, and may be an early and discriminatory marker of rejection. This led us to investigate prospectively whether monitoring of serum TNF levels was of value clinically, and was associated with effects on circulating PC and PS levels, or alterations in intragraft thrombomodulin expression. Plasma samples (n = 454) were collected three times/week from all patients (n = 25) undergoing renal transplantation during a 9-month consecutive period, and assayed by ELISA and functional assays for TNF, PC, and free PS (FPS). Portions of renal biopsies, taken to evaluate episodes of acute deterioration of renal function, were evaluated by immunoperoxidase labeling for the presence and distribution of TNF, thrombomodulin, PC, PS, thrombin, fibrin, and factors V and VIII. Comparison of 78 plasma samples collected during 26 episodes of biopsy-proven acute cellular rejection with samples collected during periods of stable renal function (n = 349) showed that TNF levels rose significantly (390 +/- 242 pg/ml, p less than 0.01) above background levels 3 days before rising serum creatinine concentrations, and peaked (2,426 +/- 978 pg/ml) on the day of clinical rejection. PC-antigen (Ag) concentrations also decreased 3 days before rejection (68 +/- 13%, p less than 0.05), and were maximally depressed (49% +/- 16%, p less than 0.001) on the day of rejection. FPS levels were normal until the day before rejection (63% +/- 8%, p less than 0.01) and, like PC, were maximally depressed (43 +/- 10%) at rejection. Plasma TNF levels were significantly and inversely correlated with PC-Ag (p less than 0.001) and FPS (p less than 0.005) levels during rejection, regardless of whether such rejection episodes were steroid responsive or required OKT3 monoclonal antibody therapy. TNF, PC, and FPS levels were normal during episodes of cyclosporine toxicity and viral infection.(ABSTRACT TRUNCATED AT 400 WORDS)

Biomarkers↗
PubMed1992

Inhalation toxicity of chromium from Whetlerite dust in rats.

The acute inhalation toxicity and metabolic fate of chromium and copper from Whetlerite dust in rats were investigated. Groups of male and female, Sprague-Dawley rats were exposed to Whetlerite dust and base carbon dust as outlined in the OECD Limit Test guidelines. At 14, 28 and 180 days post-exposure, rats were evaluated for gross pathological changes and tissues were collected for chromium and copper determination. Four deaths occurred during or post-exposure, but did not appear to be compound related. No gross pathological changes were observed at necropsy in either group. Organ chromium concentrations were below detection limits of 0.5 micrograms Cr/g dry tissue in both exposure groups. According to OECD guidelines, neither Whetlerite dust nor base carbon dust demonstrated an acute inhalation toxicity.

Administration, Inhalation↗
PubMed1989

Inorganic chemistry of chromium and its speciation in Whetlerite.

Chromium compounds are among the impregnants that enhance the ability of carbon air filters to absorb and destroy toxic agents such as CK and AC. The possibility of inhaling chromium-containing carbon dust from such filters has caused concern because, in addition to being an essential nutrient, chromium has been identified as a chemical carcinogen in humans. The essentiality or carcinogenicity of chromium depends upon its chemical speciation. Solubility and oxidation state are particularly important factors in assessing the potential hazards associated with the possible inhalation of chromium-containing dusts from these impregnated carbons or Whetlerites. The chemical speciation of the chromium in Whetlerite was found to be: from 0.6 to 1.3% insoluble trivalent chromium; from 1.0 to 1.3% insoluble hexavalent chromium; and from 0.7 to 0.9% soluble hexavalent chromium. The impregnation process, and the resulting speciation of chromium in Whetlerite, is consistent with the inorganic chemistry of chromium.

Air Pollutants, Occupational↗
PubMed1989

Speciation, bioavailability, and systemic distribution of chromium from Whetlerite dust.

Exploratory studies were conducted to determine if chromium from Whetlerite dust is bioavailable when administered intratracheally to rats, and if so, to determine its speciation. These studies indicated that chromium in this form and by this route of administration was bioavailable and was found in the trivalent state only. Less than 25% of the administered dose was recovered after 4 h, suggesting that most of the chromium was rapidly absorbed, distributed, and eliminated. Most of the chromium was found in the lungs and kidneys. The time course in the kidney suggests that this organ may be involved in the metabolism and elimination of trivalent chromium. Unexpected mortality in the experimental group of rats may have been due to the copper content of the Whetlerite, which exceeded the LD50 in the dose administered.

Animals↗