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Biomedical subjects

C Cahan

Publications and source records attributed to C Cahan.

10 recordsLinked to original sources
PubMed1996

Pulmonary function abnormalities in type I Gaucher disease.

The purpose of this study was to determine the prevalence of pulmonary function and radiographic abnormalities among patients with type I Gaucher's disease, and to analyse the relationship between the pulmonary involvement and genotype and clinical severity score. All patients attending the Gaucher clinic at the Shaare Zedek Medical Center, Jerusalem, Israel, during the years 1992-1993 were prospectively evaluated. Each patient had pulmonary function tests, chest radiography, clinical assessment in terms of degree of organ involvement, and genotype analysis. Of the 95 patients included in the study (mean +/- SD age 29 +/- 15 yrs), 68% had some pulmonary function abnormalities, most commonly a reduced FRC and transfer coefficient for carbon monoxide (Kco), found in 45% and in 42% of the patients respectively. Total lung capacity (TLC) was reduced in 22% of the patients and forced expiratory flows in approximately one third of the patients. Signs of airtrapping (elevated residual volume (RV) or RV/TLC) were seen in 18% of the patients. Males had a higher incidence of reduced expiratory flow than females, (forced expiratory volume in one second (FEV1) was reduced in 36% of males vs 5% of females). Chest radiographic abnormalities were found in 17% of the patients, although only 4% had severe changes. Patients with abnormal pulmonary function had a significantly higher severity score index than those with normal pulmonary function tests. There was no association between abnormal pulmonary function and genotype or age. In conclusion, abnormal pulmonary function is common among type I Gaucher patients. Pulmonary function tests show airways obstruction, with reduced expiratory flows, reduction in lung volumes and alveolar-capillary diffusion abnormality. The rate of progression and the clinical significance need to be determined.

Adolescent↗
PubMed1995

Erythropoietin levels with treatment of obstructive sleep apnea.

The effect of nasal continuous positive pressure (CPAP) treatment on erythropoietin (EPO) was examined by measuring diurnal serum EPO levels before and twice (over the 3rd day and over 1 day on recall after > or = 1 mo of therapy) after initiation of treatment in 12 obstructive sleep apnea syndrome patients with normal hemoglobin, hematocrit, creatinine, blood urea nitrogen, and albumin levels. Over each study day, oxygen saturation was measured by an ambulatory pulse oximetry system. Patients spent 27 +/- 9% (SE) of time below oxygen saturation of 88% vs. 2.1 +/- 0.6% after initiation of nasal CPAP treatment (P < 0.01). The number of desaturation events per hour of sleep before nasal CPAP treatment was 62 +/- 6 vs. 9 +/- 2 with nasal CPAP (P < 0.01). EPO levels measured by radioimmunoassay were drawn every hour before and at 3 days (n = 9) and before and at recall (n = 0) after initiation of CPAP therapy. The mean serum EPO level was higher before treatment (61 +/- 14 mU/ml) than that at 3 days (38 +/- 10 mU/ml, P < 0.01) or at recall (32 +/- 7 mU/ml, P < 0.01). We conclude that nasal CPAP treatment of sleep-disordered breathing will reduce diurnal levels of EPO.

Adult↗
PubMed1994

Insulin levels, blood pressure and sleep apnea.

This report concerns the relative contributions of body weight and sleep apnea to the following cardiovascular risk factors: blood pressure, fasting insulin and fasting glucose. We cross-sectionally examined the relationship of various levels of apneic activity [apnea-hypopnea index (AHI)] and a measure of obesity [body mass index (BMI)] to mean morning blood pressure and fasting serum insulin and fasting blood glucose concentrations sampled the morning after polysomnography. Subjects were 261 males (age 47 +/- 13 years, mean +/- SD), who were referred to a sleep laboratory for symptoms of sleep-disordered breathing. The dependent variables, mean morning blood pressure, insulin and fasting blood glucose (FBG) levels, were significantly related to both AHI (eta'2 = 0.10) and BMI (eta'2 = 0.18). AHI and BMI combined to account for approximately 30% of the variability in the best linear combination of these three factors. Further analysis indicated that mean morning blood pressure and fasting insulin levels each correlated positively with BMI and AHI, whereas FBG correlated only with BMI. We conclude that, although these data do not prove a causal relationship, there is evidence for an independent association between sleep apnea and not only blood pressure, but also fasting insulin levels.

Adult↗
PubMed1993

Arterial oxygen saturation over time and sleep studies in quadriplegic patients.

This study evaluated arterial oxygen saturation (SaO2) over time in a randomly selected group of quadriplegic patients to assess whether clinical history prospectively correlated with profiles of oxygen saturation. In 16 stable male quadriplegic patients (C4-T5), we used pulse oximetry to measure SaO2 over a 24 hour period. Measured values of SaO2 were formatted into a cumulative frequency distribution of SaO2 over time. The cumulative SaO2 values from the quadriplegic patients were compared to SaO2 values in a control group of 12 age-matched healthy male subjects. Ten quadriplegic patients had SaO2 profiles comparable to the range observed in healthy subjects. Six quadriplegic patients had SaO2 profiles outside of the normative range. These 6 exhibited cyclic desaturations (> 4%) during periods of behaviorally-defined sleep, suggestive of sleep-disordered breathing. During wakefulness, however, their values of SaO2 were within the normative range. With respect to level of injury, age, time after injury, or medication use, there was no difference between the six 'hypoxic' quadriplegic patients and the 10 'normoxic' quadriplegic patients. Five of the 6 hypoxic patients had a positive medical history of snoring and increased daytime sleepiness, as compared to 6 of 10 normoxic patients who gave a similar history. We also performed polysomnographic studies in a subgroup of 7 quadriplegic patients. In this subgroup, sleep-disordered breathing was observed in 3 patients (AHI of 54/53/12 per hour, respectively). We conclude that in quadriplegic patients, in whom there is a low clinical suspicion for sleep-disordered breathing, there can occur significant decreases in SaO2 over time.

Adult↗
PubMed1992

Diurnal variations in serum erythropoietin levels in healthy subjects and sleep apnea patients.

We measured arterial oxygen saturation (SaO2) and serum erythropoietin (EPO) levels in patients with obstructive sleep apnea syndrome (OSAS) and in healthy subjects. SaO2 profile was analyzed as the cumulative distribution of SaO2 over time. OSAS patients spent 25.5 +/- 30.9% (SD) of the time at SaO2 of less than 88% vs. 0.64 +/- 1.6% in healthy subjects (P less than 0.05) and had 59 +/- 25 desaturations (greater than 4%) per hour vs. less than 5 per hour in healthy subjects (P less than 0.05). EPO measurements (radioimmunoassay) were made in blood samples withdrawn every 1 or 2 h over a 24-h period. The mean EPO concentration was higher (P less than 0.05) for OSAS patients (45 +/- 33 mU/ml) than for normal subjects (17 +/- 8 mU/ml). There was a significant variability in EPO values over the 24-h period. To analyze the EPO pattern over 24 h, EPO time series were fit to a general cosine function. Data from normal subjects conformed to a cosine function with an amplitude of 3.5 +/- 2.1 (CV of 60%) and an acrophase of 1,000 +/- 184 min after 0800 (CV of 18%), indicating a zenith about 1 A.M. and a nadir around 1 P.M. Data from OSAS subjects fit a similar cosine function with an amplitude of 19.9 +/- 41.0 (CV of 206%) and acrophase of 582 +/- 408 min (CV of 70%), indicating a greater variability in the magnitude and the timing of peak serum EPO levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Assessing the characteristic between length of hypoxic exposure and serum erythropoietin levels.

We examined the relationship between the duration of hypoxic exposure and serum erythropoietin (EPO) production. Adult male Long-Evans rats were exposed to hypobaric hypoxia (HH = 0.5 atm) for a period of 15 min to 20 days. Serum for EPO by radioimmunoassay was collected immediately, 1 or 2 h after HH exposure. A significant rise in EPO levels occurred 1 h after a 30-min HH exposure that was not sustained 2 h after termination. One hour of HH exposure resulted in increased EPO levels 1 h after termination of exposure and further increased levels 2 h after termination of exposure. With prolonged exposure, serum levels remained elevated at 6 and 20 days, despite the development of polycythemia. We concluded that the hypoxic stimulus for elevation of serum EPO could be as short as 30 min and that EPO levels remained elevated after chronic HH. The experimental data were consistent with a mathematical model in which stimulated EPO production was proportional to the time of HH stimulus.

Animals↗
PubMed1990

Agreement between noninvasive oximetric values for oxygen saturation.

We made an assessment of five pulse oximeters in regard to their ability to replace the HP ear oximeter as a noninvasive measurement of SaO2. Trials were performed during isocapnic progressive hypoxia (SaO2 range, 99 to 70 percent) in 22 white and six black subjects. Comparisons between values of SaO2 by oximetry were analyzed by comparing the difference of values by the two methods against their mean. The difference between pulse oximeters and the HP was 2.6 +/- 10.3 percent in all subjects. Results in whites were 1.9 +/- 10.2 percent and in blacks were 5.1 +/- 9.2 percent. The distribution of differences between pulse oximeters and the HP were larger below 80 percent than above 85 percent. We conclude that pulse oximeters give higher values than the HP, a tendency which is more pronounced in black than in white subjects. While the limits of agreement are better at saturations above 85 percent, the 95 percent confidence limits of agreement between pulse oximeters and the HP are rather large (+/- 10 percent) and unacceptable for assuming that pulse oximeters will provide the same values as found in clinical studies using the HP.

Adolescent↗
PubMed1985

Guillain-Barré syndrome after epidural anesthesia: direct nerve root damage may trigger disease.

Guillain-Barré syndrome (GBS) appeared in four patients 1 to 2 weeks after epidural anesthesia. In all patients, clinical diagnosis was confirmed by CSF findings and nerve conduction velocity studies. Although epidural anesthesia has not been listed as an antecedent event in GBS, evidence for the relationship has been previously reported. Interaction between the anesthetic agents and peripheral nervous system myelin or local trauma to roots may initiate a cascade of immunologic events that result in the demyelinating neuropathy.

Adult↗
PubMed1984

Deterioration of beta-receptor-adenylate cyclase function in elderly, hospitalized patients.

Salbutamol infusion was used to study the molecular basis for reduced catecholamine responsiveness in a group of elderly hospitalized individuals. Salbutamol-induced plasma cyclic 3', 5'-adenosine monophosphate (cyclic AMP) rise in a group of 10 elderly (mean age 77 years) patients, 8 of whom were hospitalized 6 to 8 weeks after femoral fracture, and 10 younger (mean age 27 years) individuals was compared. Parallel clinical response was monitored by changes in pulse rate and blood pressure. In the younger group there was a three-fold increase in plasma cyclic AMP levels after salbutamol infusion. In the older adults only a one-and-one-half-fold rise in plasma cyclic AMP levels was observed. There was an increase in pulse rate and systolic blood pressure and a decrease in diastolic blood pressure in the younger group compared with the older participants. These results suggest that the basis for reduced catecholamine responsiveness in elderly hospitalized individuals is due to a defect in the peripheral beta-receptor-linked adenylate cyclase complex.

Adult↗