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N Punjabi

Publications and source records attributed to N Punjabi.

8 recordsLinked to original sources
PubMed2000

Abbreviated method for assessing upper airway function in obstructive sleep apnea.

STUDY OBJECTIVES: Previous studies have shown that the level of flow through the upper airway in patients with obstructive sleep apnea (OSA) is determined by the critical closing pressure (Pcrit) and the upstream resistance (RN). We developed a standardized protocol for delineating quasisteady-state pressure-flow relationships for the upper airway from which these variables could be derived. In addition, we investigated the effect of body position and sleep stage on these variables by determining Pcrit and RN, and their confidence intervals (CIs), for each condition. DESIGN: Pressure-flow relationships were constructed in the supine and lateral recumbent positions (nonrapid eye movement [NREM] sleep, n = 10) and in the supine position (rapid eye movement [REM] sleep, n = 5). SETTING: University Hospital Antwerp, Belgium. PATIENTS: Ten obese patients (body mass index, 32.0+/-5.6 kg/m(2)) with severe OSA (respiratory disturbance index, 63.0+/-14.6 events/h) were studied. INTERVENTIONS: Pressure-flow relationships were constructed from breaths obtained during a series of step decreases in nasal pressure (34.1+/-6.5 runs over 3.6+/-1.2 h) in NREM sleep and during 7.8+/-2.2 runs over 0.8+/-0.6 h in REM sleep. RESULTS: Maximal inspiratory airflow reached a steady state in the third through fifth breaths following a decrease in nasal pressure. Analysis of pressure-flow relationships derived from these breaths showed that Pcrit fell from 1.8 (95% CI, -0.1 to 2.7) cm H(2)O in the supine position to -1.1 cm H(2)O (95% CI, -1.8 to 0.4 cm H(2)O; p = 0.009) in the lateral recumbent position, whereas RN did not change significantly. In contrast, no significant effect of sleep stage was found on either Pcrit or RN. CONCLUSIONS: Our methods for delineating upper airway pressure-flow relationships during sleep allow for multiple determinations of Pcrit within a single night from which small yet significant differences can be discerned between study conditions.

Airway Resistance↗
PubMed1997

The first reported outbreak of dengue hemorrhagic fever in Irian Jaya, Indonesia.

During the months of September 1993 through February 1994, an outbreak of hemorrhagic fever occurred in the city of Jayapura, the provincial capital of Irian Jaya, Indonesia. Seventy-two patients (age range = 1-41 years) with suspected dengue hemorrhagic fever (DHF) were enrolled into the outbreak investigation conducted during October-November 1993. The pediatric patient population consisted of 36 individuals ages 1-12 years of age with a similar male to female ratio. From clinical histories obtained from the children diagnosed with DHF (n = 23), the predominant complaints were fever (100%), headache (96.7%), vomiting (47.8%), abdominal pain (39.1%), back/bone pain (39.1%), cough (39.1%), sore throat (21.7%), convulsions (17.4%), and eye pain (13.0%). Clinical findings of the same pediatric patients included a positive tourniquet test result (100%), thrombocytopenia (100%), hemoconcentration (100%), skin petechiae (43.5%), epistaxis (39.1%), and maculopapular rash (26%). All four of the children diagnosed with DHF grade IV had hepatomegaly, pleural effusion, ascites, cold perspiration, and confusion. Serologic data demonstrated that a majority (46 of 70, 68.7%) of the individuals assessed did not have significant levels of IgM specific for dengue viruses at the time of their admission. However, the nine successful dengue virus isolations were only from these serononreactive cases (19.6%). From the other patients assessed, 11.4% had a primary (or first exposure) serologic response to dengue virus antigen (predominantly IgM); 17.1% had a secondary (or subsequent exposure) serologic response to the same dengue antigens (predominantly IgG response) and 5.7% (four adults) had indeterminate serologic data that could not differentiate between reactivity to dengue or Japanese encephalitis virus antigen preparations. Virus culture of blood samples produced nine dengue virus isolates: DEN- 1 (2), DEN-2 (1), and DEN-3 (6). Japanese encephalitis and influenza viruses were not isolated from blood and pharyngeal specimens, respectively, from any of the patients. Thus, this first reported outbreak of DHF in Irian Jaya, Indonesia was found to be attributed to dengue viruses types 1, 2, and 3.

Adolescent↗
PubMed1994

Exposure of immature rats to hyperoxia increases tracheal smooth muscle stress generation in vitro.

Recently, we demonstrated that chronic exposure to hyperoxia causes in vivo airway muscarinic receptor hyperresponsiveness in the developing rat [Am. J. Physiol. 262 (Lung Cell. Mol. Physiol. 6): L263-L269, 1992]. To test whether airway cholinergic hyperresponsiveness might result from intrinsic alterations in smooth muscle contractility, we measured the effect of in vivo hyperoxia on the contractile force elicited by acetylcholine (ACh) of isometrically mounted tracheal rings in vitro. Tracheal rings were obtained from 3-wk-old rats exposed to air or to > 95% O2 for 8 days. Muscarinic responses were determined by measuring the force elicited by exposure to increasing concentrations of ACh. Responses were normalized to the morphometrically determined tracheal smooth muscle cross-sectional area in a plane perpendicular to the axis of force generation. In vivo O2 exposure significantly increased maximal ACh-induced stress generation (response to 10(-3) M ACh: air, 15.92 +/- 1.37 g/mm2; O2, 21.78 +/- 1.52 g/mm2; P = 0.010). The ACh-induced stress generation of cylinders from hyperoxic rats was substantially reduced by both epithelial removal and treatment with the cyclooxygenase inhibitor indomethacin. We conclude that in vivo hyperoxic exposure increases tracheal smooth muscle contractile function in vitro and that epithelium-derived prostaglandin(s) contributes to the observed increase in maximal contractile responsiveness.

Animals↗
PubMed1992

Safety and immunogenicity of single-dose live oral cholera vaccine CVD 103-HgR in 5-9-year-old Indonesian children.

Oral vaccines offer great promise as public-health measures to prevent disease in less-developed countries. CVD 103-HgR, a genetically engineered, attenuated, Vibrio cholerae O1 strain has proved effective in industrialised countries. We have assessed the safety, immunogenicity, and excretion of this live cholera vaccine in children in north Jakarta, Indonesia. 412 children aged 5-9 years received single doses of 5 x 10(6), 5 x 10(7), 5 x 10(8), 5 x 10(9), or 1 x 10(10) colony forming units (CFU) of CVD 103-HgR or placebo (5 x 10(8) inactivated Escherichia coli K-12) with buffer. All doses were well tolerated. The 5 x 10(8) CFU dose, which is highly immunogenic in subjects in industrialised countries (greater than 90% seroconversion), elicited seroconversions of vibriocidal antibody in only 16% of Indonesian children. By contrast, a single 5 x 10(9) CFU dose of vaccine resulted in high rates (75% and 87%) of seroconversion with two different batches of vaccine. A batch prepared with a centrifugation step gave significantly higher geometric mean titres (16-fold increase over baseline) than did a batch in which there was a filtration step between fermentation and lyophilisation (10-fold increase over baseline). At a 5 x 10(9) CFU dose, CVD 103-HgR is well tolerated and highly immunogenic in Indonesian children and should therefore be further investigated for use as a one-dose live oral cholera vaccine in developing countries.

Administration, Oral↗
PubMed1992

Hyperoxia-induced airway hyperresponsiveness and remodeling in immature rats.

We exposed 21-day-old rats to either normoxia or hyperoxia (greater than 95% O2) for 8 days and assessed in vivo airway responsiveness to aerosolized and intravenous methacholine (MCh) and airway architecture. Airway responsiveness was determined using a plethysmographic method. Hyperoxia increased airway cholinergic responsiveness, as reflected in a decreased mean ED200 (concentration of MCh required to increase respiratory system resistance by 100%) for both aerosolized MCh [air exposed, 5.94 +/- 2.50 vs. O2 exposed, 0.29 +/- 3.34 (SD) mg/ml, P = 0.0013, unpaired t test] and intravenous MCh (air, 1.40 x 10(-8) vs. O2, 2.45 x 10(-10) mol/kg, P = 0.0002). Airway morphometry was studied in a separate cohort of animals. After fixation by distension with Formalin at 25 cmH2O pressure, each airway cross section was photographed, and airway circumference, epithelial area, and smooth muscle layer area were determined by means of contour tracing using a digitizing pad and microcomputer. For the small airways (circumference less than 1,000 microns), hyperoxia increased both mean epithelial thickness (air, 4.88 +/- 0.53; O2, 8.64 +/- 0.90 microns) and mean smooth muscle layer thickness (air, 2.69 +/- 0.11; O2, 4.79 +/- 0.56 microns; P less than 0.0001 for each). O2 had similar effects on the larger (1,000-3,000 microns) central airways (P less than 0.0001 for both layers). We conclude that chronic hyperoxic exposure induces both airway hyperresponsiveness and airway wall thickening in immature rats.

Aerosols↗
PubMed1992

Gas dispersion in volume-cycled tube flow. II. Tracer bolus experiments.

We present a new method for rapid measurement of local gas dispersion in volume-cycled tube flow. After a small bolus of tracer gas (argon) was injected into the oscillating flow, the time-averaged effective diffusion coefficient (mean value of Deff/D) for axial transport of a tracer gas is evaluated from local argon concentration measurements taken by a mass spectrometer. Two methods are presented for the evaluation of mean value of Deff/D from the concentration measurements: one uses all the sampled data, and the other uses only the local peaks of the concentration. Experiments were conducted in two tubes (radius = 0.85 or 1.0 cm) over a range of frequencies (0.42 less than or equal to f less than or equal to 8.5 Hz) and tidal volumes (7 less than or equal to VT less than or equal to 48 ml). The experimental results show very good agreement with the theoretical predictions of Elad et al. (J. Appl. Physiol. 72: 312-320, 1992). In the absence of oscillations (static fluid), the resulting mean value of Deff/D converges to that of molecular diffusion. We also show that concentration data may be acquired at any radial or axial position, not necessarily at the tracer gas injection point, and the resulting mean value of Deff/D is independent of the spatial position of the sampling catheter. This method is of similar accuracy and is substantially faster than previous methods for measuring gas dispersion in oscillatory flows. The rapidity of these measurements may permit this method to be used for the in vivo assessment of gas transport properties within the pulmonary system.

Argon↗