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Biomedical subjects

A Behar

Publications and source records attributed to A Behar.

At least 37 records · Page 2Linked to original sources
PubMed1990

The high, medium, and low method--a better noise reduction rating?

This paper compares hearing protector attenuations calculated using National Institute for Occupational Safety and Health (NIOSH) method No. 1 ("long method") and the HML method. The study was done on 144 combinations of 12 noises and 12 protectors. In each case, the attenuation was calculated using each of the above methods. The difference between attenuations was used to define the accuracy of the high, medium, and low (HML) method. It was found that the attenuations calculated using the HML method are almost always lower than those calculated using the NIOSH method. However, the differences between both attenuations are well within the field noise level measurement errors. Consequently, the HML method appears to be an acceptable approximation of the NIOSH method, offering the additional advantage of being easier to apply. The higher accuracy of the HML method, when compared to the Noise Reduction Rating (NRR), makes is preferable for applications in industrial hearing conservation programs.

Ear Protective Devices↗
PubMed1989

[Edematous syndromes caused by capillary hyperpermeability. Diffuse angioedema].

Edema due to increased capillary permeability (ICP) may be diffuse or localized. Local edemas (Quincke edema, angioneurotic edema) are most often allergic or very rarely due to a defect in C1-inhibitor. Generalized edemas due to ICP share the following clinical features: Fluid retention (subcutaneous edema and diffused swelling) is predominant in lower limbs; it is worsened by orthostatism and warmth and alleviated by decubitus and cold, with important weight variations between morning and evening. It is associated with enhanced thirst, hypotension, oliguria, headaches and blood volume reduction; secondary hyperaldosteronism is the main mechanism. These troubles are due to ICP, associated with lymphatic drainage abnormalities; ICP is measured by the isotopic Landis Test. This abnormality is present in several diseases. Idiopathic orthostatic edema (IOE) is frequent and often unrecognized, occurring mainly in women, often associated with luteal insufficiency. Iatrogenic complications (diuretic and laxative abuses) are frequently superimposed. ICP may be corrected by vitamins P (rutin, anthocyanosides, diosmin, Ginkgo biloba extracts...) Cyclic shock due to ICP is rare. It is characterized by cyclic edema and shock with hypovolemia, hypoproteinemia; the mechanism of shock is a severe loss of fluid and protein from the vascular bed. It is often associated with monoclonal gammapathy and complement activation. In our personal case, the trouble in CP was present all along the disease with permanent edema and low blood pressure (especially in orthostatism). Vit "P" and Ginkgo biloba extracts were able to partially improve CP and the clinical troubles. However, in spite of this treatment a fatal shock occurred after ten years follow-up. Episodic angioedema associated with eosinophilia was first described by Gleich.(ABSTRACT TRUNCATED AT 250 WORDS)

Capillary Permeability↗
PubMed1987

Isotopic test of capillary permeability to albumin in diabetic patients: effects of hypertension, microangiopathy, and duration of diabetes.

Capillary permeability to albumin (CPA) was studied by performing an isotopic noninvasive test with venous compression on 87 nonselected diabetics with no edema, no cardiac failure, and no peripheral vascular disease. Excessive albumin retention (AR greater than or equal to 8%) ten minutes after removal of the compression was found in 27 patients (31%). The radioactivity disappearance curve was then analyzed using the Fast Fourier Transform (FFT). An abnormal isotopic CPA test was thus found in at least 45 out of the 87 patients. The prevalence of an abnormal test was not different in type 1 and type 2 diabetics. We studied the independent effects of hypertension, presence of specific clinical signs of microangiopathy (retinopathy and/or significant proteinuria), and duration of diabetes. Among diabetics free of specific clinical signs of microangiopathy, the prevalence of an AR greater than or equal to 8% was significantly higher in those with hypertension (11/19) than in those with normal blood pressure (2/28) and in nondiabetic hypertensive patients (0/16). Among normotensive diabetics, the prevalence of an abnormal test was higher, but not significantly, in patients with specific clinical signs of microangiopathy (8/11) than in those free of them (7/18). Seven normotensive diabetics without specific clinical signs of microangiopathy had an abnormal test; five of them had had diabetes for more than five years. The prevalence of diabetes of more than five years duration was significantly higher in patients with an abnormal test (35/45) than in normotensive diabetics free of specific clinical signs of microangiopathy with a normal test (4/11).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Idiopathic cyclic edema. The role of capillary hyperpermeability and its correction by Ginkgo biloba extract].

Idiopathic cyclic oedema is a frequent and often unrecognized condition in young women. It is characterized by water and sodium retention with secondary hyperaldosteronism due to capillary hyperpermeability. Treatment is not easy. It includes spironolactone, sometimes sympathomimetics and hygienic-dietetic measures. Thiazide diuretics and laxatives must be avoided. Correcting the capillary defect is of paramount importance. This defect is detected and measured by Landis' labelled albumin test. The authors have tried Ginkgo biloba extract administered either orally or by intravenous infusion. Full correction of the biological anomaly was obtained in 10 cases in which Landis' test was performed before and after oral treatment, and in the 5 cases treated by intravenous infusion.

Capillary Permeability↗
PubMed1985

Noise exposure--sample size and confidence limit calculation.

In a previous paper a method for assessing noise exposure levels of workers from the same trade was presented. There was also discussed how to apply the NIOSH sample size method to noise exposed populations. In this paper both subjects are further discussed by including the calculation of confidence limits for the mean noise exposure as well as for the percentage of workers with noise exposure levels beyond a certain level. The calculation of the sample size of a population where standard deviation is known is also discussed.

Environmental Exposure↗
PubMed1984

Noise exposure--sampling strategy and risk assessment.

Noise exposure surveys are performed to assess risk of hearing loss. Because of the large populations that are usually involved, there is a need for a sampling procedure that will ensure statistically significant results. After the survey has been performed, the risk has to be assessed in a meaningful manner so that management can easily evaluate the situation. In this study noise exposure levels were found to be normally distributed. As a result, the NIOSH sampling method could be applied for noise exposure surveys. Furthermore, it is shown how different degrees of risk can be assessed as the percentage of workers with exposure lower than 85 dBA, higher than 90 dBA or between 85 and 90 dBA. A numerical example in the Appendix shows how the procedure is applied in a practical situation.

Hearing Loss, Noise-Induced↗
PubMed1983

[Ovarian function in orthostatic idiopathic edema. Oral administration of progesterone and changes in capillary permeability].

The ovarian function was investigated in 30 women with postural idiopathic oedema by measuring plasma oestradiol and progesterone levels between the 21st and 23rd days of the menstrual cycle. Plasma progesterone concentrations were found to be lower than 5 ng/ml in 53% of the cases and than 10 ng/ml in 83%. The ovarian dysfunction most frequently observed was inadequate corpus luteum, i.e. progesterone deficiency with normal plasma oestradiol levels. In virtually all patients the initial disorder in capillary permeability, as evaluated by Landis' isotopic test, was fully corrected by progesterone administered orally. However, clinical improvement was less marked with treatments of short duration (2-3 consecutive cycles). In view of the complex pathogenesis of the disease, combined treatments in which progesterone might well play the major role are usually required.

Administration, Oral↗
PubMed1983

[Dynamic study of the diffusion and clearance of proteins in human interstitial tissue].

The application of a venous tourniquet leads to distension of the distal venous and capillary circulation and a local increase in plasma volume. In the normal subject, plasma volume returns to its initial level within approximately 10 sec of tourniquet release. In subjects affected by cyclical oedema, the local increase in plasma volume persists several minutes after tournique release. Radioactive labelling of plasma proteins shows that this delay is associated with the retention of plasma proteins by the tissues. These proteins are subsequently cleared by lymphatic drainage or diffusion back into veins. These results suggest that the combination of tournique test with the labelling of plasma proteins measures capillary and venous permeability as well as tissue protein clearance kinetics.

Body Fluid Compartments↗
PubMed1981

[Effectiveness of various hormonal preparations in adults with hypothyroidism (author's transl)].

Among more than 7000 adult patients with suspected dysthyroidism in who radioimmune assays were performed, the authors have selected 21 patients with high TSH hypothyroidism who had assays before and after replacement therapy with various preparations prescribed by their G.P. The results in this group of 61 treatments of at least 3 weeks duration were as follows: (1) under thyroid extract or thyroglobulin (21 treatments), the condition persisted in the majority of patients; (2) under thyroxine (31 treatments), the thyroid function returned to normal with a once-a-day dose of 150 mcg/-T4; (3) under triiodothyronine (7 treatments), none of the patients reverted to euthyroidism. Levothyroxine therapy therefore appears to be the most effective and cheapest way of providing optimal replacement therapy in patients with hypothyroidism. The daily dose of about 150 mcg can easily be adjusted according to the results of occasional hormonal assays.

Humans↗
PubMed1979

Idiopathic edema.

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Diagnosis, Differential↗