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Biomedical subjects

I Weisman

Publications and source records attributed to I Weisman.

15 recordsLinked to original sources
PubMed1996

Proximity of iliosacral screws to neurovascular structures after internal fixation.

The placement of iliosacral screws for the stabilization of pelvic ring lesions is technically demanding. The postoperative computed tomography scans of 31 patients who had 57 iliosacral screws placed for various indications were studied to determine the proximity of these screws to neurovascular structures. The closest distance of the screws from the S1 foramen averaged 3 mm. (range, 0-10.5 mm); the average closest distance to the anterior cortex of the sacral ala was 4.8 mm (range, 0-15.3 mm). The corridor for the insertion of the screws between the S1 foramen and the anterior cortex of the sacrum averaged 21.7 mm (range, 16.2-28.9 mm). Trigonometric analysis of these dimensions suggests that deviations of the surgeon's hand by as little as 4 degrees may direct iliosacral screws either into the S1 foramina or through the anterior cortex of the sacrum.

Bone Screws↗
PubMed1987

Surface character and membranolytic activity of rutile and anatase: two titanium dioxide polymorphs.

Biological studies of two titanium dioxide polymorphs, rutile and anatase, have produced conflicting results. Generally, the in vivo and in vitro methods used to evaluate pneumoconiotic dusts have shown the polymorphs to be inert, but occasionally both minerals have been reported to produce effects consistent with biologically active minerals. Many of these reports failed to specify which polymorph was used experimentally. While this limited the value of the data, the problem was further compounded by the variation in the surface properties of each polymorph depending on whether the specimen was a naturally occurring mineral or was made synthetically. Five naturally occurring and 11 synthetically produced titanium dioxide specimens were studied. The physical characterisation of each specimen entailed the determination of the polymorph type(s) by continuous scan x ray diffraction and the size distribution by transmission electron microscopy. The ability of each specimen to lyse erythrocytes was determined and compared with quartz. Only two, both synthetic rutiles, were found to be active. The hydrogen bonding ability of the surfaces of these rutiles were compared with inert rutile and quartz. The binding properties of the active rutile have been found to be consistent with those properties associated with biologically active quartz. The surface properties of rutile are the determinants of its activity. Because natural and synthetic rutiles possess different surface properties, they display different activities.

Hemolysis↗
PubMed1985

Saccadic eye movements among copper smelter workers.

Saccade accuracy was studied in 87 copper smelter workers. Findings were compared with those obtained in 52 lead-exposed automobile production workers and 52 controls examined as part of a separate study. Both groups of workers showed a decrease in saccade accuracy compared to controls. Saccade accuracy was reduced in copper smelter workers over 50 years of age compared to automobile production workers in this age group. Decreased saccade accuracy was not correlated with blood lead (Pb-B), zinc protoporphyrin (ZPP), or urinary arsenic (As-U) levels among copper smelter workers, but was significantly correlated with both Pb-B and ZPP in the group of automobile production workers. Saccade accuracy decreased significantly with age and duration of exposure only in the group of copper smelter workers. Complex exposures to lead and other toxic agents present in the smelter may account for the reduction in saccade accuracy among copper smelter workers.

Adolescent↗
PubMed1984

Occupational lead exposure. Effects on saccadic eye movements.

Quantitative measures of saccadic eye movements were examined in 52 lead exposed autobody shop workers and 52 age matched controls with no history of occupational lead exposure. Three characteristics of saccadic eye movements were studied: 1) saccade accuracy; 2) number of overshoots; and 3) maximum velocity. The results indicated that workers exposed to inorganic lead showed a decrease in saccade accuracy and an increase in overshoots compared with controls. Saccade maximum velocity was lower in lead exposed workers than in controls but the difference was just short of statistical significance. Correlations between measures of saccadic eye movements and indicators of lead absorption--blood lead (Pb-B) and zinc protoporphyrin (ZPP) levels--were analyzed in the lead exposed workers. Saccade accuracy was negatively correlated with both Pb-B and ZPP levels. The number of overshoots was not correlated with either Pb-B or ZPP levels. Saccade maximum velocity was not correlated with Pb-B, however, there was a significant negative correlation with ZPP. Age effects observed in the control group were disrupted in lead exposed workers. In addition, saccadic eye movements in younger workers (below 30 years old) were more affected by exposure to inorganic lead than were saccadic eye movements in older workers (50 years and older). It is proposed that these findings are consistent with a relatively rapid buildup of metabolically active lead burden observed in the study group. The data suggest that quantitative assessment of eye movements may be an important tool for studying subclinical central nervous system (CNS) dysfunction due to inorganic lead exposure.

Adult↗
PubMed1983

Positive gallium-67 scintigraphy associated with pulmonary embolism.

A 54-year-old man presenting with symptoms and signs of pulmonary embolism demonstrated gallium-67 accumulation within the right lower lung field in the region of a pulmonary embolism with effusion. An associated infectious process was ruled out. This is contrary to the usual clinical experience and identifies a potential pitfall in the use of gallium-67 as an aid in the differential diagnosis of pulmonary embolism and pneumonitis.

Diagnosis, Differential↗
PubMed1980

Comparative lead emissions from conventional and jacketed ammunition.

Because of the adverse health effects associated with excessive exposure to lead in firing ranges, attempts have been made to develop ammunition which could prevent such undesirable exposure. This study provides evidence that it is possible to reduce lead exposure significantly at the source of emission with the use of copper and nylon jacketed bullets.

Environmental Exposure↗
PubMed1980

Environmental asbestos concentrations in the United States.

Measurements were made of chrysotile concentrations in buildings with asbestos-lined return air plenums, in buildings with damaged asbestos surfacing material, in the houses of asbestos workers, and around buildings while asbestos-containing fireproofing material was being sprayed on steelwork. The data obtained demonstrate significant environmental contamination by asbestos: 43/89 air samples exceeded 50 ng/m3, although only 2/89 samples exceeded 1000 ng/m3. These findings should prompt appropriate control or remedial action.

Air↗
PubMedDate not supplied

Tolerance to and efficacy of itraconazole in treatment of systemic mycoses: preliminary results.

Twelve patients with mycotic infections were treated with itraconazole during a one-year period. Patients had the following conditions: coccidioidomycosis (three), histoplasmosis (three), mucocutaneous candidosis (two), aspergillosis (three), and urinary tract infection due to Torulopsis glabrata (one). The daily dose of itraconazole ranged from 100 to 200 mg. Ten of the 12 cases were assessable. Clinical improvement was observed in six patients, two with coccidioidomycosis, two with mucocutaneous candidosis, one with histoplasmosis, and one with aspergilloma. Four patients did not respond to therapy; two of these patients had aspergillosis, one had histoplasmosis, and one had T. glabrata infection. No adverse effects were attributable to itraconazole.

Adult↗