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Biomedical subjects

D Kurtz

Publications and source records attributed to D Kurtz.

At least 55 records · Page 3Linked to original sources
PubMed1988

Renal function in patients with obstructive sleep apnea. Effects of nasal continuous positive airway pressure.

Patients with obstructive sleep apnea (OSA) often exhibit nocturnal polyuria, which disappears with nasal continuous positive airway pressure (CPAP) treatment. We measured water and electrolyte urinary excretion, creatinine and osmolal clearances, and water transport during sleep in 13 polygraphically monitored patients with OSA during two consecutive nights, either untreated or treated with nasal CPAP, and in eight normal subjects. Untreated patients with OSA had greater urinary flows and greater urinary sodium, chloride, and potassium excretions than did controls. Nasal CPAP treatment in patients with OSA resulted in a reduction in urinary flow and in sodium and chloride excretion, with a concomitant increase in sodium resorption. None of these effects was observed in CPAP-treated normal subjects. The only effect of nasal CPAP common to normal subjects and patients was a trend toward decreased glomerular filtration rate.

Adult↗
PubMed1988

[Magnetic resonance imaging and herpetic encephalitis].

Cerebral lesions in two cases of herpetic encephalitis were detected by MRI using a spin-echo sequence and delayed echo signal recordings, whereas CT scans were normal. In one case pathology showed lesions to be more extensive than MRI anomalies. This suggests that even in the absence of EEG and CT anomalies, an encephalitis can be suggested by MRI.

Electroencephalography↗
PubMed1986

A family study of the association of increased ventricular size with schizophrenia.

Families with more than one individual of the same generation with the diagnosis of schizophrenia were recruited for studies. Brain lateral ventricular size was quantified in 26 schizophrenic subjects from 12 unrelated families, their available well siblings (N = 10), and 20 nonpsychotic controls. Lateral ventricular size was significantly greater in the schizophrenics than in their well siblings and controls. In addition, an analysis of variance of the data showed a significant familial component to ventricular size. Although histories of head injury and birth complications were also associated with ventricular size, these were not sufficient to explain both the familial aspect of ventricular size and the association of greater ventricular size with schizophrenia within these families.

Adult↗
PubMed1986

Effect of low doses of estradiol on 6-month growth rates and predicted height in patients with Turner syndrome.

We randomly assigned 16 girls with Turner syndrome, age 5 to 15 years, to receive treatment with 100 ng/kg/day ethinyl estradiol or placebo for 6 months, with crossover after a 2-month interim period. We assessed growth by measurement of the 4-week lower leg growth rate and by height velocity. Bone age was determined at the beginning and end of treatment. Growth rate during ethinyl estradiol treatment was approximately 70% greater than during placebo (P less than 0.001), without any bone age advancement relative to that with placebo. The change in predicted height was significantly greater after 6 months treatment with ethinyl estradiol than after treatment with placebo (mean +/- SEM, +0.35 +/- 0.38 cm vs. -0.85 +/- 0.32 cm, P less than 0.03). Breast budding occurred in six patients. We conclude that it may be feasible to begin low-dose estrogen therapy to promote growth at an earlier age than would be conventionally used to induce pubertal development. These data are still relatively short term, however; until long-term data are available, it would be premature to make definitive recommendations regarding the dose and timing of estrogen treatment in Turner syndrome.

Adolescent↗
PubMed1986

A teaching file program for use in an ultrasound department.

A radiology teaching file program has been developed for use in an ultrasound department. Sonographic findings and diagnoses for each case are stored as groups of key words drawn from a vocabulary of up to 2000 key words created by the user. The program runs on a microcomputer and allows storage of 5000 cases per 360 kilobyte floppy disk. Data entry is accomplished entirely by ultrasound technologists based on the ultrasound report. Cases may be retrieved by selecting either individual key words or groups of key words, and the results may be printed out in a variety of formats. Experience in using the system over a 12-month period is discussed.

Humans↗
PubMed1985

Vertebral bone mineral content in osteogenesis imperfecta.

Quantitative computed tomography of the lumbar spine was carried out in 28 patients with osteogenesis imperfecta (OI) in order to measure vertebral trabecular bone mineral concentration (BMC). The patients ranged in age from 6-73 years, and included 3 of the 4 major clinical subtypes of the disease. The findings underscore the heterogeneity of osteogenesis imperfecta even among family members with the same disease type. In addition, cross-sectional analysis of Type I OI patients suggests that BMC during young adulthood averages about 70% of normal, and subsequently falls more rapidly than in normal patients. BMC tends to be lower in the more severe forms of OI. Decreased BMC was not found in a few otherwise normal relatives with scoliosis or joint laxity.

Adolescent↗
PubMed1985

Eye position during fixation tasks: comparison of macaque and human.

Two macaques and three humans fixated luminous targets in a dark field. All subjects had greater dispersion of eye position from trial-to-trial (between-trial variability) than would be predicted from sampling error and within-trial variability. Monkeys had greater between-trial dispersion on the vertical meridian than humans because of less precise control of saccades. Mean vertical eye position of the monkeys varied idiosyncratically with the fixation task (spot-dim or line-tilt). Between-trial fixation variability of both monkeys and humans was large enough to affect the interpretation of experiments relating visual performance to retinal anatomy or to neurophysiology.

Adult↗
PubMed1985

Flow-volume curve abnormalities and obstructive sleep apnea syndrome.

Recent reports have suggested that flow volume curve abnormalities may be of interest in the diagnosis of obstructive sleep apnea syndromes by showing either extrathoracic airway obstruction (ratio of expiratory flow to inspiratory flow at 50 percent of forced vital capacity [FEF50/FIF50] exceeding 1) or upper airway fluttering (indicated by a sawtooth aspect on the mid-half of the inspiratory part of the curve) or both. In our study, 57 patients referred for a suspected sleep apnea syndrome (SAS) underwent conventional spirometry, assessment of flow-volume curves, ENT examination, and polysomnography. Thirty patients had an obstructive SAS, four patients a central SAS, and 23 patients no SAS. Signs of upper airway fluttering (the sawtooth sign) were present in 61 percent of the patients with obstructive SAS and in 46 percent of the patients without obstructive SAS (central SAS or no SAS). Signs of extrathoracic upper airway obstruction (FEF50/FIF50 greater than 1) were present in 67 percent of the patients with obstructive SAS and in 71 percent of the patients without obstructive SAS. These results suggest that upper airway abnormalities, as reflected by abnormal flow volume curves, are not always associated with obstructive SAS; they favor the hypothesis of a central component in the mechanism of upper airway occlusion during sleep.

Female↗
PubMed1985

[Sleep and nocturnal desaturation of patients with chronic obstructive bronchopneumopathies. Effects of almitrine bismesylate administered orally].

In order to verify the effect of almitrine bismesylate on episodes of nocturnal oxygen desaturation, 10 patients suffering from chronic obstructive pulmonary disease had polygraphic EEG night sleep recordings with simultaneous measurement of O2 saturation. The subjects presented during nocturnal sleep a quantity of desaturation of at least 2,400 sec. X p. cent (this quantity being represented by the surface of the SaO2 curve under the desaturation level defined as the waking SaO2 less 4 p. cent) and had been included in a matched experimental protocol, double blind, almitrine bismesylate versus placebo. After administration of either placebo or almitrine bismesylate for 14 days (100 mg per day in two doses) a control night sleep recording was performed. The effect of treatment was assessed using an analysis of variance for 2 or 3 factors, completed by a Student t test in case of significant interaction between the factors. It appears that almitrine bismesylate produces: a non significant decrease in total sleep, slow wave sleep and REM sleep time; a significantly earlier awakening (p less than 0.05); a significant reduction of the total duration of desaturation episodes (p less than 0.05) without any correlation with the variations of total sleep time; a non significant decrease in the quantity of desaturation; a significant increase in PaO2 (p less than 0.001) and in SaO2 (p less than 0.01) measured two hours after the awakening. However there was no evidence of any significant change in mean SaO2 and lowest SaO2 during the night. Finally the variability of the effect of almitrine bismesylate during day or night time remains unexplained.

Administration, Oral↗
PubMed1984

[Continuous positive pressure in the treatment of sleep apnea syndromes].

Continuous positive airway pressure as a long-term home treatment for sleep apnea syndromes would seem to present irreconcilable requirements; it must be simple and comfortable to use during sleep and it must be relatively inexpensive. The device described in this paper includes a compressor, an individually molded nose-mask and a water column. Improvements are still in progress, but, as it stands, it enables sleep apnea patients to be successfully treated at home.

Humans↗
PubMed1984

[Sleep apnea syndromes. Treatment with continuous positive pressure by the nasal route].

Nine patients with severe, predominantly obstructive sleep apnoea syndromes were treated during one night by continuous positive pressure under polygraphic monitoring. Three patients did not tolerate the treatment for either mechanical reasons (2 cases) or ventilatory reasons (1 case). In the remaining 6 patients, continuous positive pressure resulted in reorganization of sleep and disappearance of obstructive and central apnoeic episodes. This effect was incomplete at low pressure (2 cm H2O) and complete at pressures of 6 to 10 cm H2O. The fact that continuous positive pressure was effective against both obstructive and central apnoea suggests that its mode of action is not purely mechanical but involves the central ventilatory control, probably by a reflex mechanism. In view of its effectiveness, continuous positive pressure appears to be the treatment of choice for sleep apnoea syndromes.

Aged↗
PubMed1984

Isosignal contours and signal gradients as an aid to choosing MR imaging techniques.

The signal strength of a magnetic resonance (MR) image depends on a variety of factors, including the tissue properties of proton density (p) and relaxation times (T1 and T2) and the scanning sequence. Given this complex interrelation of factors, a graphic method of displaying the image intensity for various tissue properties is needed. In this paper we use isosignal contour curves to display "topographically" the relationships of signal intensity to the tissue properties of p, T1, and T2 for a variety of operator settings in the techniques of saturation recovery, inversion recovery, and spin echo. We further demonstrate the utility of these curves in explaining image appearances and in choosing appropriate pulse sequences for imaging.

Brain Stem↗