Effects of smoking tobacco on exercise tolerance in healthy subjects

The aim of the study was to investigate the effects of smoking on exercise tolerance in middle aged smokers. Sixty two healthy subjects 55 males and 7 females with mean age 35 +/- 7 years were studied. There were 47 smokers (smoking 21.5 cigarettes per day for a mean of 16 years) and 15 non-smokers (control group). Resting pulmonary function was normal in both groups, however smokers had significantly lower VC as well as MEF 50 and MEF 75. A maximal incremental exercise on cycloergometer using ramp protocol was performed. Ventilatory parameters (breath by breath method) together with transcutaneous oxygen saturation (every minute), heart rate (continuously) and blood pressure (every minute) were recorded. Significant differences in exercise tolerance in studied groups were observed. Smokers tolerated a lower maximal workload for a shorter time and deferred significantly in both maximal oxygen consumption and oxygen consumption at anaerobic threshold. Five persons, all smokers did not reach the anaerobic threshold. In five smokers a decrease in ECG ST segment was observed. No differences were found in breathing reserve, heart reserve or maximal oxygen pulse. It seems that a decreases exercise performance is due to cardiac limitation.     

Sertraline treatment does not increase plasma prolactin levels in healthy subjects

Peliosis is a rare disease that is characterized by multiple blood-filled cystic spaces. We report the computed tomographic findings of splenic rupture secondary to splenic peliosis in a patient receiving anabolic steroids for aplastic anemia.     

Effects of tryptophan depletion on responses to yohimbine in healthy human subjects

There is considerable evidence that both the norepinephrine (NE) and serotonin (5-HT) systems are involved in the regulation of human anxiety and fear responses. To assess the modulating effects of central 5-HT levels on NE function, 11 healthy human subjects were studied with placebo-controlled challenge tests involving tryptophan depletion followed by administration of the alpha-2-adrenergic antagonist yohimbine 0.4 mg/kg IV. Five of the 11 subjects reported a marked increase in feelings of nervousness (> or = 25 mm on a 100 mm analog scale) following the combination test, while 1/11 had this response to yohimbine alone. No subjects had an increase in nervousness during other control tests. The increase in nervousness after the tryptophan depletion-yohimbine test was statistically significant for the whole group, but there were no other unique changes in behavioral, physiologic or biochemical (MHPG, cortisol) variables with this test. These data are discussed in terms of possible functional interactions between the 5-HT and NE neurotransmitter systems.     

Effects of exposure to hypoxia on the signal-averaged electrocardiogram in healthy subjects

The effects of hypoxia on the signal-averaged ECG (SAECG) were investigated in 26 healthy active subjects with no suggestion of cardiac disease. The SAECG was recorded in each resting subject in normoxic and hypoxic normobaric conditions (inspired O2 fraction 20.7 vs 10.0%) which lowered resting arterial O2 saturation from 98.6 +/- 0.6% to 77.7 +/- 8%. Recordings from four subjects (three men) met the definition of abnormal late potentials at baseline; in all these subjects but one, who exhibited an improved but still abnormal QRS duration, these parameters returned to normal in hypoxic conditions. The duration of the filtered QRS was significantly reduced (from 107.6 +/- 13.2 to 101.6 +/- 11.3 ms, P < 0.01), the duration of the low amplitude signals in the terminal portion of the QRS < 40 microV (LAS) significantly decreased (from 26.5 +/- 9.5 to 22.7 +/- 7.9 ms, P < 0.05) and the root mean square voltage in the last 40 ms (Term-RMS) increased non-significantly (from 55.8 +/- 40.2 to 69.1 +/- 38.3 microV, P = 0.058). Hypoxia determined a higher (P < 0.05) heart rate increase in subjects with abnormal records than in normal subjects. These data could be related to a sympathic discharge. They suggest that: (1) variation in heart rate could affect the SAECG; (2) exposure to hypoxia improves SAECG parameters in healthy subjects, possibly related to sympathetic discharge; (3) abnormal records collected during sinus bradycardia could represent a type of false-positive expression of late potentials in young active adults.     

Minimal daily variations of plasma and urinary endothelin-1 in healthy subjects

The daily profiles of both the plasma level and the urinary excretion rate of endothelin-1 were examined in 13 healthy volunteers (9 males and 4 females, aged 22 +/- 1 [SEM]). Plasma endothelin-1 (PET) was measured after a one-hour recumbency every 6 hours at 8 a.m., 2 p.m., 8 p.m. and 2 a.m. and the urinary excretion rate of endothelin-1 (UET) was determined in the urine collected every 6 hours. PET was found to be quite stable throughout the day, being 1.57 +/- 0.25 pg/ml at 8 a.m., 1.88 +/- 0.21 at 2 p.m., 2.2 +/- 0.24 at 8 p.m. and 1.90 +/- 0.20 at 2 a.m. After a one-hour ambulation, PET showed no statistical difference. UET also remained unchanged for each 6-hour collecting period, measuring 4.61 +/- 0.69, 3.98 +/- 0.46, 4.63 +/- 0.73 and 3.42 +/- 0.49 ng/hr, respectively. The absence of any daily variations in either PET or UET thus suggests that apparently no specific considerations need be applied regarding the time of taking samples to measure the plasma and urinary endothelin-1.     

Identical effects of indomethacin on renal function in healthy uninephrectomized subjects and in healthy control subjects

1. Animal studies have shown that prostaglandins are important for renal function after unilateral nephrectomy. In order to investigate the importance of prostaglandins for renal function in the fully adapted remnant kidney in healthy uninephrectomized subjects, the acute effects of indomethacin on renal haemodynamics, lithium clearance, urinary excretion rates of prostaglandin E2, sodium and water, and plasma levels of angiotensin II, aldosterone, atrial natriuretic peptide and arginine vasopressin were measured in 14 healthy uninephrectomized subjects (median time after nephrectomy 1.7 years) and in 14 matched healthy control subjects. In addition, nine healthy control subjects were studied without indomethacin and served as a time-control group. 2. Before indomethacin ingestion there was a significantly higher single-kidney urinary excretion rate of prostaglandin E2 in the uninephrectomized group (uninephrectomized group, 349.2 fmol/min; control group, 76.6 fmol/min; time-control group, 96.3 fmol/min). 3. Indomethacin ingestion resulted in equal changes in all parameters in both groups. These were significant decreases in glomerular filtration rate (-11.3% versus -14.6%), renal plasma flow (-6.5% versus -13.0%), urinary flow rate (-49.8% versus -49.4%), fractional sodium excretion (-44.5% versus -47.4%), lithium clearance (33.2% versus -23.8%) and urinary excretion rate of prostaglandin E2 (-93.8% versus -86.7%) (uninephrectomized versus control subjects, values are medians). In the time-control group no changes were observed in these parameters. 4. It is concluded that healthy uninephrectomized subjects with a fully adapted remnant kidney have a normal renal response to acute indomethacin-induced inhibition of prostaglandin synthesis.     

Effects of consumption of oat milk, soya milk, or cow''s milk on plasma lipids and antioxidative capacity in healthy subjects

The effect of hydration and benzene adsorption on 23Na resonance and the quadrupolar interaction in NaY zeolites is studied by triple-quantum MAS 23Na NMR spectroscopy. In the case of a C6D6/NaY system, the results show that with an increase in benzene loading, there is an up-field trend in isotropic chemical shift (delta CS) and a decreasing second order quadrupolar effect (chi s) for the site II sodium ions. It was found that adsorbed benzene molecules have a slight effect on the environment of sodium ions on site I. All the sodium sites in NaY are influenced upon hydration. The up-field shift of the sodium delta CS reflects the effect of coordination of oxygen atoms on sodium cations due to hydration. The magnitude of chi s for hydrated sodium sites increases and then falls off with water loading. The increase in chi s is due to the initial hydration among SI-, SI'- and SII-sodium ions, while the decrease is the result of approaching the final stage of saturated hydration.     

Effects of oral glucose on intermediary metabolism in continuous ambulatory peritoneal dialysis patients versus healthy subjects

AIM OF THE STUDY: Retrospective analysis of result of radical cystectomy at Cochin Hospital. PATIENTS AND METHODS: We report the results of a 106 patients series treated by radical cystectomy for bladder carcinoma after a 5-year period follow-up. RESULTS: The extent of the tumour invasion according to pathological analysis was: pT1 or less: 26%, pT2 and pT3a: 33%, pT3b and over: 41%. Morbidity rate was 19% with a 7.5% reintervention rate. Long term complication rate was 31%, concerning essentially ureteral stenosis. A local recurrence or distant metastasis occurred in 35% of patients. Local recurrence rate was 10.7%. Cancer specific survival rates were 88%, 81% and 42% for pT1, pT2-pT3a, and pT3b patients respectively. CONCLUSION: The present results confirm that radical cystectomy is the most effective curative treatment for invasive bladder carcinoma.     

Influence of hyperglycaemia on maximal gastric secretion in healthy subjects

The influence of a single intravenous glucose load on maximal gastric acid secretion in 25 healthy men when stimulated with pentagastrin was studied. Under the influence of hyperglycaemia, a highly significant decrease of maximal acid output was found. Moreover, in the gastric juice an increase of chloride and calcium concentrations was noted. On the other hand, the output of potassium, chloride and magnesium was lowered. The above differences were statistically significant.     

Effects of NMDA antagonism on striatal dopamine release in healthy subjects: application of a novel PET approach

We investigated the in vitro erythroid progenitor growth and the effects of sera on normal-marrow CFU-E (colony-forming units - erythroid) growth in 2 patients with renal failure on regular hemodialysis following a prior history of polycythemia vera (PV). PV was diagnosed 3 and 11 years, respectively, before the development of terminal renal failure. One of the patients had entered a spent phase of PV as characterized by diffuse extensive myelofibrosis and anemia; the other also had mild myelofibrosis. The serum erythropoietin (EPO) levels were low or normal on serial measurements by radioimmunoassay. There was no correlation between the hematocrit values and serum EPO levels. EPO-independent erythroid colonies were present in the cultures of bone marrow and peripheral blood cells from both patients after renal failure in the anemic state. With the addition of various concentrations of EPO, the number of erythroid colonies increased as the concentrations of EPO increased which was in accordance with the clinical observation that 1 patient with postpolycythemic myeloid metaplasia partially responded to recombinant human EPO therapy. In the EPO-dependent CFU-E assay, normal-marrow CFU-E numbers supported by 10% of the patient sera were less than those by normal sera. In the absence of EPO in cultures, no erythropoietic activity was found in the patients' sera. Our study on uremic patients with underlying PV showed that the biologic characteristics of autonomous erythroid progenitor growth for PV persisted during the spent phase and after the development of terminal renal failure with anemia. The erythroid progenitors responded to EPO both in vitro and in vivo. Their sera exhibited an inhibiting effect on the growth of normal-marrow erythroid progenitors.     

Pupillographic assessment of sleepiness in sleep-deprived healthy subjects

Medical research frequently involves the statistical comparison of >2 groups, often using data obtained through the application of complex experimental designs. Fortunately, inferential statistical methodologies exist to address these situations. Analysis of variance (ANOVA) in its many forms is used to simultaneously test the equality of all groups in a study. One-way (with 1 independent variable), 2-way (with 2 independent variables), and repeated-measures (patients serve as their own controls) ANOVAs are forms of this technique. Each form has been developed to analyze data from a specific experimental design. Analysis of covariance (ANCOVA) allows the researcher to control for confounding variables that may influence the response of the dependent variable. Finally, multivariate analysis of variance (MANOVA) evaluates the simultaneous responses of multiple dependent variables to > or = 1 independent variable. Whereas ANOVA is the correct alternative to statistically inappropriate multiple t-tests, MANOVA is the correct alternative to statistically inappropriate multiple univariate ANOVA calculations. Use of each of these statistical methods requires an appropriate experimental design and data meeting a number of assumptions. When used properly, each of these methods provides a powerful statistical analysis technique.     

Effect of different levels of hyperoxia on breathing in healthy subjects

We have recently shown that breathing 50% O2 markedly stimulates ventilation in healthy subjects if end-tidal PCO2 (PETCO2) is maintained. The aim of this study was to investigate a possible dose-dependent stimulation of ventilation by O2 and to examine possible mechanisms of hyperoxic hyperventilation. In eight normal subjects ventilation was measured while they were breathing 30 and 75% O2 for 30 min, with PETCO2 being held constant. Acute hypercapnic ventilatory responses were also tested in these subjects. The 75% O2 experiment was repeated without controlling PETCO2 in 14 subjects, and in 6 subjects arterial blood gases were taken at baseline and at the end of the hyperoxia period. Minute ventilation (VI) increased by 21 and 115% with 30 and 75% isocapnic hyperoxia, respectively. The 75% O2 without any control on PETCO2 led to 16% increase in VI, but PETCO2 decreased by 3.6 Torr (9%). There was a linear correlation (r = 0.83) between the hypercapnic and the hyperoxic ventilatory response. In conclusion, isocapnic hyperoxia stimulates ventilation in a dose-dependent way, with VI more than doubling after 30 min of 75% O2. If isocapnia is not maintained, hyperventilation is attenuated by a decrease in arterial PCO2. There is a correlation between hyperoxic and hypercapnic ventilatory responses. On the basis of data from the literature, we concluded that the Haldane effect seems to be the major cause of hyperventilation during both isocapnic and poikilocapnic hyperoxia.     

Reliability of cephalic thermal thresholds in healthy subjects

Reproducibility and normal variation of cephalic warm and cold detection thresholds were investigated in three healthy subject groups. The face, the mastoid process, and the hands were studied. No significant intra-observer test-retest difference (n = 20) was found. Good reliability (intra-class correlation coefficient [ICC] > 0.4) was found for 13 of 14 measurements. A small significant inter-observer difference (n = 20) was found for cold thresholds. Good reliability (ICC > 0.4) was observed for both cold and warm thresholds in most of the test locations (6 of 8). In general, the largest variability was found in the mastoid and frontal lateral regions. Thermal thresholds varied with investigation site in 56 controls (ANOVA, p < 0.0005). No significant gender differences were found for cephalic warm and cold thresholds. Most cold thresholds (4 of 5) but also some warm thresholds (2 of 5) increased with age at the cephalic sites. Our results reveal the frontal medial, the maxillar medial, and lateral regions as the most reliable cephalic test locations. The mastoid region may also be useful for investigating the upper cervical small-fiber function.     

Acute effect of ursodeoxycholic acid on gallbladder volume in healthy subjects

The features of time domain and power spectrum of high frequency electrocardiogram (HF-ECG) were studied in normal Kunming mice using a microprocessor ECG system. The results were as follows (mean +/- SD): (1) P-R interval was 34.9 +/- 4.7 ms (n = 58), about one third of the cardiac cycle. (2) The duration and peak-to-peak amplitude of QRS complex were 9.2 +/- 1.2 ms and 1.456 +/- 0.480 mV (n = 74) respectively. (3) The duration and amplitude of T wave were 10.2 +/- 3.2 ms and 0.336 +/- 0.115 mV, respectively (n = 58). (4) Q-T interval was 19.4 +/- 3.2 ms (n = 58), about one fifth of the cardiac cycle. (5) The total number of notches and slurs of leads II of 73 mice were 3 and 26 respectively. (6) The relative power content of each frequency range was: 0-80 Hz: 45.48 +/- 15.32%; 80-200 Hz: 43.97 +/- 9.95%; 200-300 Hz: 8.89 +/- 7.83%; 300-1000 Hz: 1.66 +/- 2.74%; 80-1000 Hz: 54.52 +/- 15.32%.     

Electrocardiographic changes during insulin-induced hypoglycemia in healthy subjects

Hypoglycemia is associated with alterations of the ECG, a phenomenon which might be used for the development of a hypoglycemia detection device. We investigated the reproducibility and magnitude of ECG alterations during insulin-induced hypoglycemia in nine healthy volunteers. The subjects were studied twice with an identical study protocol on two different study days. During hypoglycemia frequent ECG recordings were done with a conventional 12 lead ECG. S.c. injection of 0.15 U/kg of regular insulin induced a fourfold increase in insulinemia on both study days as well as a mean decline in blood glucose by 1.6 mmol/l to a minimum of 2.8 mmol/l within 60 min after injection. Blood potassium levels declined by a mean of 0.25 mmol/l to minimal values of 3.69 mmol/l. On both study days, a progressive flattening of the T-waves was observed during the experiments. R-waves remained constant leading to an increase in RT ratios by at least 50% in comparison to baseline values. These changes were most pronounced in leads I, V3, V5 and V6. The magnitude and reproducibility of the observed ECG changes during hypoglycemia may allow the development of a hypoglycemia detection device.     

Effect of intravenous pyridoxine on plasma prolactin in hyperprolactinemic subjects

Intravenous pyridoxine has been reported to lower plasma PRL in normal subjects and in patients with the amenorrhea-galactorrhea syndrome. We tested the effect of pyridoxine (300-mg iv bolus) on plasma PRL in nine patients with hyperprolactinemia due to a variety of causes. There was no effect of pyridoxine on elevated plasma PRL in any of the nine hyperprolactinemic subjects. The potential utility of pyridoxine in the long term treatment of the galactorhea-amenorrhea syndrome will require further study.     

Effects of chlordiazepoxide, buspirone and cocaine on behavior suppressed by timeout presentation

Male Wistar rats were exposed to a two-component multiple schedule: a random-interval 30 s schedule of pellet presentation and a conjoint random-interval 30 s schedule of pellet presentation, random-interval 2 s schedule of timeout 10 s presentation. Once responding had stabilized subjects were injected intraperitoneally with vehicle, chlordiazepoxide (1-30 mg/kg), buspirone (0.1-4.2 mg/kg) or cocaine (1-30 mg/kg), 15 min before the start of the experimental session. Before drug administration, punished response rates were less than 30% of unpunished response rates for four of the six subjects, and 60% and 75% for the other two. Low doses of chlordiazepoxide (1 and 3 mg/kg) increased punished responding (range 25-300%), and slightly increased unpunished response rates (by 25% in all but one subject, whose rates increased by 75%). The higher doses of chlordiazepoxide (10-30 mg/kg) dose-dependently decreased response rates in both components. The lower doses of buspirone (0.1 and 0.3 mg/kg) either did not affect, or decreased response rates in both components of the schedule; the higher doses produced dose-dependent decreases. Low doses of cocaine (1, 3 and 5.6 mg/kg) did not affect response rates in either component of the multiple schedule, whereas higher doses produced a dose-dependent decrease in response rates, except for one subject whose punished response rates increased substantially. The behavioral effects of chlordiazepoxide and buspirone observed in the present experiment were similar to those observed in experiments in which response rates were suppressed by shock presentation.