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Biomedical subjects

S Baron

Publications and source records attributed to S Baron.

At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

Innate defences against viraemia.

Human blood plasma has been reported to possess nonspecific antiviral activity. This activity is due to several preexisting naturally occurring molecules that are either active against individual members or a family of viruses. These molecules, however, have not been adequately studied to reveal their molecular structures and mechanisms of action presumably because of their low and nonspecific antiviral action. Therefore, their possible role against viraemia remains unknown. Recently, two naturally occurring nonspecific broad-spectrum antiviral agents, University of Texas Inhibitor beta (UTIbeta) glycoprotein and high density lipoprotein, have been described in human serum. They are active against DNA and RNA viruses and one of them, UTIbeta, possesses significant antiviral activity of 40 units/mL. Since preexisting antiviral molecules in serum appear to be the only defence mechanisms available at the onset of viral infection they may have protective significance against viraemia. In view of this potential, we have undertaken to review the properties of these innate viral inhibitory molecules.

Antiviral Agents↗
PubMedDate not supplied

Bacteria and viruses induce production of interferon in the cerebrospinal fluid of children with acute meningitis: a study of 57 cases and review.

The CSF of 57 infants and children with bacterial or enterovirus meningitis was analyzed for the presence of interferon (IFN). CSF was collected when the diagnosis of meningitis was made; a bacterium or enterovirus was isolated in all cases. IFN was detectable in CSF in 24% of cases of bacterial meningitis and in 75% of cases of viral meningitis. Titers of IFN were generally lower in cases of bacterial meningitis. Neither the presence of IFN nor the level of IFN titers correlated with the patient's age or number of white blood cells or mononuclear cells in the CSF. Coxsackievirus induced production of IFN more consistently and in higher titers than did echovirus. None of 35 control patients had detectable IFN in CSF. A literature review and our data indicate that the presence of IFN in CSF suggests infection of the CNS but does not differentiate bacterial from viral infection. The finding of IFN in the CSF of children with bacterial meningitis supports evidence that bacteria and other nonviral microorganisms induce IFN production. The protective role of IFN in nonviral infections deserves further investigation.

Acute Disease↗
PubMedDate not supplied

Blood pressure and hormone changes associated with weight reduction in the obese.

This study examines factors modulating blood pressure reduction in obese patients undergoing weight reduction on a low calorie protein diet. Plasma norepinephrine (NE) was correlated (r = 0.65, p less than 0.01) with blood pressure in 20 obese patients prior to weight loss. Reductions in blood pressure levels following upright posture and isometric handgrip exercise were related to reduction in NE levels after these maneuvers. While plasma epinephrine levels declined in parallel with NE levels, plasma dopamine actually increased (p less than 0.05) during the first 2 weeks of caloric restriction. Prior to weight loss the obese patients demonstrated a significant rise in prolactin levels following posture and exercise, but following caloric restriction this was not observed. Levels of plasma renin activity (PRA) and aldosterone obtained after posture and exercise maneuvers were reduced after 8 weeks of caloric restriction, and reductions in PRA were related to reductions in NE (r = 0.56, p less than 0.01). Reductions in blood pressure in association with caloric restriction in these obese patients seems to result, in part, from reduced sympathetic nervous system activity as well as secondary effects of reduced adrenergic activity on renal sodium excretion and the renin-angiotensin-aldosterone axis.

Adult↗
PubMedDate not supplied

Pesticide-related illness among migrant farm workers in the United States.

Surveillance data show that pesticide-related illness is an important cause of acute morbidity among migrant farm workers in California. A few categories (organophosphates and carbamates, inorganic compounds, and pyrethroids) account for over half of the cases of acute illness. Skin effects dominate the illnesses, although ocular and systemic effects are also common. Exposures occur in various ways (e.g., residues, drift), suggesting that the use of pesticides creates a hazardous work environment for all farm workers. The health care system provided through the Migrant Health Program appears to be underutilized, partially due to barriers to health care access. Pesticide hazards should be ranked based on acute toxicity, chronic toxicity (including reproductive risks), carcinogenic potency, volume applied, and magnitude of worker poisonings. Current surveillance effort should be supported. Risk prevention should focus on substitution of safer compounds, establishing effective protections, and ensuring that these measures are enforced. Improved education for health care providers should be a priority. Growers should be educated about alternative forms of pest control and incentives should be provided to encourage their use.

Agricultural Workers' Diseases↗
PubMedDate not supplied

[Evaluation of tracheobronchial lesions with spiral CT: comparison between virtual endoscopy and bronchoscopy].

INTRODUCTION: The aim of this study is to describe the scanning parameters for virtual bronchoscopy in the evaluation of the tracheobronchial tree and to compare the results of this examination with the endoscopic findings. MATERIAL AND METHODS: 27 patients with tracheobronchial neoplasms suspected at preliminary clinical and chest film findings or postoperative follow-up for malignant disease were evaluated with spiral CT of the chest and bronchoscopy. Virtual endoscopy was performed on the pulmonary volume involved by the lesion, using narrow axial images (thickness 2 mm, table index 3 mm, reconstruction index 1 mm.) so as to obtain MPR, MIP and 3D reconstructions with 3D Endo Vew program (Philips Medical System, Eindhoven, Holland). We compared these reconstructions and the findings the normal spiral CT scanning with the corresponding endoscopic examinations. RESULTS: In all patients we were able to study the lobar and segmental bronchi in all patients and in 2 we also evaluated the subsegmental bronchi. 25 lesions in 23 patients were shown by virtual endoscopy (8 occlusions, 8 stenosis, 5 compressions, 3 flogosis with endobronchial mucus, 1 bronchocele) and in 4 patients the examinations were negative. The bronchoscopy was negative in 4 patients and positive in 23 patients with 25 lesions, but we had agreement in 23/27 patients (85,1%). In 2 patients virtual endoscopy showed the lesions in a different bronchus compared to bronchoscopy. In one patient we interpreted the obstruction as neoplastic instead of mucus inside the bronchi and in the last patient bronchoscopy was not performed due to his old age and the virtual endoscopy showed total obstruction of a segmental bronchus. DISCUSSION AND CONCLUSIONS: The results show that virtual endoscopy can study the tracheobronchial tree as far as the segmental bronchi, and sometimes also the subsegmental bronchi and the bronchi below a closed obstruction. In addition, it can evaluate the extraluminal location of the lesions. For these reasons virtual endoscopy provides a road map for bronchoscopy as a guide for transbronchial biopsy and for endobronchial treatment planning. The limitation of this technique is its inability to evaluate the mucosal surface and distinguish flogosis from neoplastic lesions by biopsy. It can be used however in the postoperative follow-up both for cancer and transplant, when immediate biopsy is not necessary.

Adenocarcinoma↗
PubMedDate not supplied

Preventing sexual transmission of HIV: anti-HIV bioregulatory and homeostatic components of commercial sexual lubricants.

Certain safe over-the-counter (OTC) sexual lubricants such as Astroglide, KY Liquid, Replens, Vagisil, ViAmor, and Wet Stuff inhibit both cell-free HIV and the production of HIV by infected leukocytes in vitro even in the presence of seminal fluid. To identify which components of the lubricants were active against HIV, we tested five components (glycerin, methylparaben, propylparaben, polyquaternium-32, and propylene glycol). The paraben preservatives and propylene glycol in the lubricants did not inhibit HIV, while the common natural homeostatic metabolite, glycerin, and the thickener polyquaternium-32 did strongly inactivate infectious HIV and HIV-infected leukocytes. Activity against HIV and HIV-infected cells by glycerin was stable through 24 hours at 37 degrees C. Glycerin and polyquaternium-32 were active at minimum concentrations of approximately 2% and 0.01%, respectively--well within the highest FDA safety guidelines. Both active components disrupted infected leukocytes within 5 minutes which resulted in inhibition of infectious HIV production by infected leukocytes of greater than 25 to 100-fold. These components do not disrupt vaginal epithelial cells in vivo. These components also rapidly inactivate cell-free HIV by 10- to 30-fold. Thus, we may conclude that the active components of the OTC lubricants are glycerin and polyquaternium-32. Using these components, OTC sexual lubricants could be reformulated to optimize their anti-HIV activity. Furthermore, clinical trials of these lubricants and components seem to be indicated because of their FDA safety level, wide availability, and low cost.

Anti-Infective Agents, Local↗
PubMedDate not supplied

Antiviral activity in urine is attributable to ammonium salts.

Urine exhibits antiviral activity in tissue culture against a number of viruses. We have characterized that antiviral activity in comparison with a number of antiviral substances which are known to be present in body fluids. We show here that the antiviral activity in urine cannot be due to the presence of contact-blocking virus inhibitor (CVI), or interferon. The findings support the conclusion that most of the antiviral activity in urine is qualitatively and quantitavely attributable to its content of ammonium salts.

Adult↗
PubMedDate not supplied

A large component of the antiviral activity of mouse interferon-gamma may be due to its induction of interferon-alpha.

The finding that interferon-gamma (IFN-gamma) may require two rounds of protein synthesis to induce the antiviral state raises the possibility that this IFN may not be directly antiviral. We, therefore, examined the possibility that IFN-gamma induces one or both of the other IFNs (alpha and/or beta) which in turn induce the antiviral state. Evidence is presented showing that under certain conditions a large portion of IFN-gamma's antiviral activity in mouse L-929 cells is mediated by its induction of IFN-alpha based on the findings that: 1) the antiviral activity of IFN-gamma in cells at low densities can be blocked by poly and monoclonal antibody to IFN-alpha and, 2) IFN-alpha can be demonstrated in the supernatant fluids of IFN-gamma treated cells. This report raises the possibility that a major antiviral mechanism of IFN-gamma is via induction of IFN-alpha in the mouse system. If the majority of the antiviral activity of IFN-gamma is via induction of other IFNs, then the role and mechanism of IFN-gamma might have to be reevaluated.

Animals↗