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Biomedical subjects

P Menon

Publications and source records attributed to P Menon.

12 recordsLinked to original sources
PubMed1992

Passive cigarette smoke-challenge studies: increase in bronchial hyperreactivity.

Degree and duration of bronchial hyperreactivity (BHR) after environmental tobacco smoke (ETS) inhalation was assessed in 31 smoke-sensitive subjects with asthma who exhibited lower airway symptoms on ETS exposure (group I) and 39 smoke-sensitive subjects without asthma who manifested only upper airway symptoms on cigarette-smoke exposure (group II). Subjects were challenged with ETS for 4 hours in a static-test chamber. The atmosphere was continuously monitored for airborne particulate levels (800 cpm), total suspended particulates (1266 +/- 283 micrograms/m3), and airborne nicotine levels (226 +/- 49 micrograms/m2). Methacholine challenges were performed before and serially after cigarette-smoke exposure, and the provocative dose causing a 20% fall in FEV1 was determined. Five of the 31 smoke-sensitive subjects with asthma and none of the smoke-sensitive subjects without asthma reacted to cigarette-smoke challenge (greater than or equal to 20% fall from baseline FEV1). Thirty-two percent (10/31) of the subjects with asthma demonstrated increased BHR at 6 hours, 29% (9/31) at 24 hours, and 13% (4/31) up to day 14 after ETS challenge. Of the subjects without asthma, 18% (7/39) demonstrated increased BHR at 6 hours, 10% (4/39) at 24 hours, and 8% (3/39) at 3 weeks. These studies demonstrated an increase in BHR after cigarette-smoke challenge in a number of study subjects (although they were clinically asymptomatic) and suggest that prolonged subclinical airway inflammation can occur in the absence of demonstrable change in airway caliber on exposure to ETS.

Adolescent↗
PubMed1991

Comparison of cockroach allergenic activity in whole body and fecal extracts.

Previous studies have established cockroach allergens as important sensitizing agents in the induction/exacerbation of urban asthma. The present investigation compared saline extracts of American cockroach (Periplaneta americana) whole bodies and feces and German cockroach (Blattella germanica) whole bodies and feces as important sources of allergens. All extracts were tested before or after gel filtration on Sephadex G-75 columns (fraction 2) as previously described. Skin test studies of 69 subjects with asthma with extracts of American or German cockroaches demonstrated a significant correlation of reactivity to whole body and fecal extracts for both species. Direct RASTs of 13 sera from cockroach skin test-positive subjects were generally greater to both German whole body extracts (GWBEs) and German fecal extracts (GFEs) as compared to American whole body and fecal extracts. There was a good correlation of RAST reactivity to GWBE with GFE. RAST inhibition demonstrated that GFE contained most of the allergenic activity present in GWBE. These studies demonstrate the allergenic similarities of cockroach whole body and fecal extracts and suggest that cockroach feces are an important sensitizing agent in atopic asthma.

Allergens↗
PubMed1991

Mortality of fecal bacteria in seawater.

We propose a method for determining the mortality rate for allochthonous bacteria released in aquatic environments without interference due to the loss of culturability in specific culture media. This method consists of following the disappearance of radioactivity from the trichloroacetic acid-insoluble fraction in water samples to which [3H]thymidine-prelabeled allochthonous bacteria have been added. In coastal seawater, we found that the actual rate of disappearance of fecal bacteria was 1 order of magnitude lower than the rate of loss of culturability on specific media. Minor adaptation of the procedure may facilitate assessment of the effect of protozoan grazing and bacteriophage lysis on the overall bacterial mortality rate.

Colony Count, Microbial↗
PubMed1991

Skin test reactivity to whole body and fecal extracts of American (Periplaneta americana) and German (Blatella germanica) cockroaches in atopic asthmatics.

Forty-six atopic asthmatic subjects aged 3 to 58 years attending the allergy clinic of a university hospital were evaluated for prick skin test reactivity with commercially available extracts of cockroach (CCE) and house dust (HD). Additionally, skin testing was performed with American cockroach whole body (AWBE) and fecal extracts (AFE) as well as German cockroach whole body (GWBE) and fecal extracts (GFE) prepared in our laboratory. Commercial cockroach extract was prepared from American, German, and Oriental cockroach whole bodies. Skin test reactivity to the different extracts were as follows: 83% to HD, 70% to CCE, 70% to AWBE and/or GWBE, 63% to AWBE, 57% to GWBE, 63% to AFE and/or GFE, 52% to AFE, 50% to GFE, 48% to both AWBE and GWBE, and 39% to both AFE and GFE. The subjects with positive skin tests to AWBE and/or GWBE (70%) were the same individuals who showed skin test reactivity to CCE (70%). Subjects from lower income families (less than $10,000) had a significantly higher skin test reactivity to cockroach allergens than those from families with an annual income of $11,000 to $24,000 (P = .04). These results demonstrate the significance of cockroach sensitization in atopic asthmatics, suggest the importance of fecal cockroach allergens, and support earlier observations of shared interspecies allergens between American and German cockroach whole bodies.

Adolescent↗
PubMed1991

Asymptomatic proteinuria and/or haematuria in 265 Malaysian adults.

Two-hundred and sixty-five patients with asymptomatic proteinuria and/or haematuria were studied at the Department of Medicine, Universiti Kebangsaan Malaysia and Department of Nephrology, General Hospital Kuala Lumpur. They represented 25.4% of all the renal biopsies performed during the period 1980-88. All the three races were affected with 71.3% occurring between the ages of 20-39 years and 41.1% were detected during routine medical examination. Excluding those patients with lupus nephritis, IgA nephropathy was the commonest histological diagnosis (51.7%). The presence of severe and advanced histological changes in a significant number of biopsies emphasises the need for more effective screening and early referral of this group of patients.

Adolescent↗
PubMed1991

IgA nephropathy in Malaysia.

A total of 164 patients with IgA nephropathy were diagnosed at the Department of Medicine, Universiti Kebangsaan Malaysia and the Department of Nephrology, General Hospital, Kuala Lumpur between 1981-1988. This represented an incidence of 20.1% of all primary glomerulopathies seen in both units. The 3 major ethnic groups were equally affected with 59.7% occurring between the ages of 20-36 years. It was not uncommon in females. The high prevalence of hypertension, renal failure, heavy proteinuria at presentation and the increased chronicity index in the biopsy, suggest that IgA nephropathy is progressive disease leading to chronic renal failure.

Adolescent↗
PubMed1990

Isotretinoin-basal cell carcinoma prevention trial. Design, recruitment results, and baseline characteristics of the trial participants. The ISO-BCC Study Group.

The Isotretinoin-Basal Cell Carcinoma Prevention Trial (ISO-BCC Study) is a double-masked, randomized, placebo controlled, multicenter clinical trial. It is the first intramural cancer chemoprevention trial sponsored by the Division of Cancer Prevention and Control of the National Cancer Institute. This trial was designed to evaluate the effectiveness of chronic administration of low dosage levels (10 mg) of a synthetic retinoid, isotretinoin, in reducing the incidence of basal cell carcinoma in a high-risk population and to determine the incidence and severity of side effects associated with this long-term treatment. Between 1984 and 1987, eight clinical centers enrolled 981 participants between the ages of 40 and 75, who had two or more biopsy proven basal cell carcinomas in the 5 years before trial entry. This article describes the trial design, recruitment results, and baseline characteristics of the participant population in the ISO-BCC Study.

Adult↗
PubMed1989

Antinuclear antibodies and anticytoplasmic antibodies in bronchial asthma.

The presence of antinuclear antibodies and anticytoplasmic antibodies was evaluated in the sera of 50 patients with bronchial asthma and 35 matched control subjects with miscellaneous medical diseases with the use of an indirect immunofluorescent assay with HEp-2 cells as substrate. The results were compared to age, sex, atopic status, dose, and duration of the antiasthmatic medication, immunotherapy, severity of the disease, and presence or absence of myalgia. The patients had mild to moderate asthma. The incidence of fluorescent anticytoplasmic antibodies (FACA) in the sera of patients with asthma was statistically significant (p = 0.02) in comparison to FACA in the sera of the control subjects. The combined incidence of fluorescent antinuclear antibodies (FANA) and FACA was found to be significantly higher among atopic subjects with asthma (p = 0.03) and the subjects with asthma and with myalgia (p less than 0.05). The 20% incidence of FACA in this group of subjects with asthma was significantly greater (p less than 0.0001) than the reported 2.7% incidence of FACA in a group of patients with various rheumatologic diseases. Variables, such as dose and duration of antiasthma medications and immunotherapy did not appear to influence the presence of FANA and FACA in their sera. The significance of positive FANA and FACA in this group of subjects with asthma is not known and needs to be evaluated by long-term studies.

Antibodies↗
PubMed1988

Assessment of response to oral metaproterenol sulfate by forced oscillation in young children.

The dose response characteristics and side effects of three doses of oral metaproterenol sulfate (MS) (0.4, 0.6, and 0.8 mg/kg) were compared with a placebo in ten asthmatic children (3 to 6 years). The bronchodilator efficacy was objectively assessed by evaluating the decrease in mean total respiratory resistance (MTRR) using Oscillaire. The mean percentage changes from baseline in MTRR showed that MS in all three doses was more effective than placebo. Lack of objective demonstration of bronchodilator efficacy, concern for possible side effects and uncertainty of the precise dosage for adequate bronchodilation are some of the factors that account for the lack of specific dosage recommendations for bronchodilators such as oral metaproterenol sulfate in children under 6 years of age. Until recently, it was not possible to objectively measure the response to bronchodilators in children below 6 years of age because of their inability to reliably perform forced expiratory maneuvers required for spirometry and their unwillingness to have airway resistance (or conductance) measurements by body plethysmography. Direct measurements of airflow resistance have been made in children with a pneumotachograph at the mouth and a balloon in the esophagus to record transpleural pressure changes; however, these techniques are invasive and require sedation. Total respiratory resistance and reactance of the respiratory system, as measured by forced oscillation technique, are pulmonary function tests that can be performed in young children who are unable to cooperate with conventional spirometric maneuvers.

Administration, Oral↗
PubMed1986

Myxedema coma.

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Aged↗