Biomedical subjects
Publications and source records attributed to N Brautbar.
Two sewer workers contracted hepatitis C. The epidemiological literature in which sewer-contaminated water is described as a known vector for outbreaks of hepatitis C, as well as the specific occupational history of the two patients described here, suggest that sewer workers may be at increased risk of contracting hepatitis C.
Chronic lead exposure may cause hypertension in normotensive rats. This hypertensinogenic effect has been attributed to perturbations in the renin-angiotensin axis, the contractile response of the vascular smooth muscle, or the intracellular Ca2+ homeostasis as a consequence of the inhibition of Na(+)-K(+)-ATPase activity. In this study we examined the short-term effect of lead exposure on blood pressure, plasma renin activity, vascular contractility, and renal Na(+)-K(+)-ATPase activity and abundance in the spontaneously hypertensive rat. Our data indicate that modest lead exposure caused blood pressure elevation within two weeks in this rat strain that is genetically susceptible to the development of hypertension. This rapid blood pressure-elevating effect did not appear to depend on the mechanisms described in hypertension associated with more chronic lead exposure listed above. This acute model provides an additional approach to the study of lead-induced hypertension.
Explore the source record for details and available documents.
We have previously shown that natural killer (NK) cell activity is significantly suppressed in patients with silicone breast implants. These patients were symptomatic and the suppression of natural killer cell activity was associated with additional significant immunological abnormalities (Vojdani et al., 1992a). Our studies have recently been confirmed by Smith et al. (1994), who described natural killer cell activity suppression following exposure to silicone gel, and reversal upon removal of the gel. This study has been designed to evaluate natural killer cell activities in symptomatic women with silicone breast implants and again after explantation of the implants. Each patient served as her own control. Our findings show a marked significant increase in previously suppressed natural killer cell activity in 50% of the patients. In the other 50%, no change or suppressed NK activity was observed. These findings are compatible with recent studies in experimental animals, which show that administration of silicone reduces natural killer cell activity, and that this is reversible upon removal of the silicone. Since NK cells are important in the control of tumor cell growth, we propose here that patients with reduced NK cell activity are at a higher risk of developing cancer, a concept recently described in experimental animals (Potter et al., 1994; Salhon et al., 1994).
The Norplant* system is composed of a set of six Silastic* (silicone polydimethysiloxane) capsules measuring 34 mm by 2.4 mm, each containing 36 mg of levonorgestrel and sealed at either end with a medical grade silicone elastomer adhesive. Levonorgestrel is a synthetic progestin, widely used in combination oral contraceptives and in single-agent "mini-pills". In a procedure completed in less than 15 minutes by an experienced physician, the six capsules are surgically implanted subdermally, most commonly on the inside of the left upper arm. The levonorgestrel diffuses through the Silastic material into the blood stream and is carried to the target organs. Ovulation is suppressed in the majority of the cycles during the first years of use, and cervical mucus is thickened, inhibiting sperm penetration. During use, the effective delivery of levonorgestrel is about 30 mcg/day from day 500 to day 2300. Recently, we have seen patients with complications from Norplant, and we describe here a patient who presented with systemic complications resulting from both the endocrinological aspects of Norplant and the immunological aspects of the Silastic implants. To our knowledge this is the first case report in the western medical literature describing systemic immunological complications as a result of a failed Norplant device.
This study examines the effects of volatile organic compounds (VOCs) at the workplace on pulmonary function tests. Forty-two patients with a history of industrial exposure to organic solvents and pulmonary symptomatology were studied. Lung function tests were determined utilizing screening spirometry lung volumes, diffusion capacity and methacholine stimulation test. While only 10-15% of the symptomatic patients had abnormal screening spirometry, 42% of the patients had significantly abnormal methacholine stimulation tests. These data show that exposure to volatile organic solvents is associated with bronchial hyperreactivity not commonly detected by screening spirometry and requires methacholine stimulation testing in individuals with unexplained symptomatology and history of exposure to industrial solvents. These findings indicate that the incidence of bronchial hyperreactivity is underestimated in patients with (1) verifiable exposure history to volatile organic compounds known to be pulmonary irritants, (2) pulmonary symptomatology with normal screening spirometry.
Sinuses are a part of the upper respiratory system and sinusitis has been well-defined as an inflammation of the mucous membrane. Sinusitis occurs commonly as a result of allergies, polyps, common cold and environmental pollution. Reports of sinusitis secondary to ammonia exposure, while common clinically from a reporting point of view, have not been described extensively in the literature. We describe here a patient who was exposed to ammonia gas and developed chronic relapsing sinusitis. The mechanism of injury and review of the world literature indicate that although common clinically, chronic sinusitis as a result of ammonia exposure has not been described extensively.
Silicone has been utilized as an implant in reconstructive surgery. For years, silicone has been considered to be biologically inert and essentially harmless. Several studies and case reports show that female patients treated with silicone implants developed a systemic disease associated with immunological abnormalities. Removal of the silicone implants was associated with recovery and resolution of the immune abnormalities. Recently, specific antibodies to silicone have been isolated in children with silicone implants. Additionally, immunological abnormalities and high incidence of systemic progressive sclerosis in patients with silicone implants or injections further support the notion that silicone is not biologically inert, and can cause a syndrome of a systemic disease and immunological abnormalities. The specific mechanisms and duration of the latency period is not yet fully understood.
Immunological abnormalities including lymphocyte subset, lymphocyte immune functional assays, chemical antibodies, and different markers for autoimmune response were examined in individuals exposed to a variety of chemicals in computer manufacturing plants. A comparison of 289 individuals exposed to chemicals to 120 controls revealed that exposed individuals had a significantly higher percentage with either increased or decreased T helper/T suppressor ratios. In addition, the individuals with abnormal T4/T8 ratios demonstrated significant elevation in chemical-hapten antibodies. Therefore, 87 exposed subjects with abnormal T4/T8 ratios were selected for further evaluation by lymphocyte phenotypic expression and T cell, B cell, NK activity, and autoimmune markers, and were compared to 60 controls. The comparison of exposed individuals with controls indicated elevation of T cell (CD3), B cell (CD19), and activated T cell (CD10, CD15, CD26, CD38), suppressed T cell and B cell function decreased or increased NK cell cytotoxic activity. Autoimmunity due to chemical exposure was evidenced by elevation of TA1 phenotype frequencies and presence of rheumatoid factor, immune complexes, ANA, and anti myelin basic protein antibodies. We conclude that chemical exposure may induce immune abnormalities including immune suppression and autoimmunity.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Silicone, previously thought to be a biologically inert and harmless material, has now been reported to elicit antibody response and to be responsible for adjuvant disease in humans. The present study was designed to evaluate the immune function of forty individuals who had undergone silicone breast augmentation for a period of longer than ten years and who were compared with 40 sex and age-matched controls. The following immunological functions were studied: lymphocyte subset analysis, lymphocyte mitogenic response, NK cytotoxic activity and markers for autoimmunity such as ANA, rheumatoid factor immune complexes such as smooth muscle, myelin, and thyroid, and tissue antibodies. Results of lymphocyte subpopulation analysis showed significantly elevated T helper/suppressor ratio in 60% and significantly decreased T helper/suppressor ratio in 7.5% of the silicone implant group, while the control group showed increased helper/suppressor ratio only in 10% of tested individuals and no significant decrease in the T helper/suppressor ratio. There was 20% inhibition in T cell mitogenic responses in the silicone implant group, which is significant when compared to the controls. When NK cytotoxic activity was compared between the two groups, significant inhibition in the ability of lymphocytes to kill tumor target cells was observed in the silicone implant group. This inability of target cell lysis was attributed to the demonstrated lack of granularity of NK cells from the silicone implant group. There was significant increase in: immune complexes, anti-nuclear antibodies, anti-thyroid antibodies, anti-striated muscle cell antibody, and anti-myelin basic protein antibodies. These immunological abnormalities in individuals who underwent silicone breast augmentation indicate a mechanism of tissue injury to these patients, causing autoimmune diseases or syndromes. Since autoimmunity in some other conditions is associated with abnormalities in the HLA serotyping system, and since some collagen vascular diseases have been associated with a higher incidence of the HLA serotyping system, it is recommended that HLA studies be included in future investigations of immune-mediated abnormalities associated with silicone breast augmentation. Our findings here show definite abnormalities of the T helper/suppressor ratio, increased autoimmunity, as well as increased production of immune complexes. Silicone implants have been used in cosmetic and reconstructive surgery more than 30 years (Brown et al., 1960). The gel used in the implant is produced from silicone, which is then related with methyl chloride and polymerized to form stable polydimethylsiloxane (Brown, et al., 1960). There have been a number of reports describing the occurrence of connective tissue disease in patients after the implantation of silicone.(ABSTRACT TRUNCATED AT 400 WORDS)