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Biomedical subjects

D Kurtz

Publications and source records attributed to D Kurtz.

At least 19 recordsLinked to original sources
PubMed1992

Frequency of certain urgent eye problems in an emergency room in Massachusetts.

The frequency and cost of emergency room care for certain ocular problems was surveyed. Superficial eye problems accounted for 2.67 percent of patients reporting to the emergency room, while 0.23 percent reported for penetrating injuries. Of the conditions surveyed, conjunctivitis was the most commonly presenting diagnosis. Abrasions and superficial foreign bodies were the next most common presentations. Together these three diagnoses accounted for nearly 75 percent of all superficial eye problems seen in the emergency room. The cost of each emergency room visit averaged $132. This study has implications for health care managers and for legislatures contemplating expanding the scope of optometric practice.

Cost-Benefit Analysis↗
PubMed1991

Sleep and breathing abnormalities in a case of Prader-Willi syndrome. The effects of acute continuous positive airway pressure treatment.

This report describes the polysomnographic findings and the respiratory alterations during sleep in a 20-year-old patient with the Prader-Willi syndrome. Nocturnal recordings and a variant of the multiple sleep latency test showed excessive daytime sleepiness, sleep onset rapid eye movement episodes, snoring and sleep apnea. Treatment with nasal continuous positive airway pressure normalized the respiratory pattern and the sleep structure, except for rapid eye movement sleep onset. Whereas upper airway obstruction and obesity may explain the respiratory disorders, as shown by their resolution with continuous positive airway pressure treatment, hypothalamic dysfunction could play a role in the disruption of the normal nonrapid eye movement/rapid eye movement sleep periodicity.

Adult↗
PubMed1991

Left ventricular ejection fraction in obstructive sleep apnea. Effects of long-term treatment with nasal continuous positive airway pressure.

The effects of treatment with nasal continuous positive airway pressure (CPAP) on left ventricular ejection fraction (LVEF) were assessed in 29 patients with obstructive sleep apnea (OSA) in a prospective study using multiple gated equilibrium radionuclide angiocardiography. All patients were evaluated before CPAP treatment was initiated and were reevaluated after one year (mean +/- SE, 415 +/- 6 days), of home treatment with nasal CPAP. The mean LVEF increased from 59 +/- 1 percent to 63 +/- 1 percent (p less than 0.005). The degree of improvement in LVEF was correlated with baseline LVEF (r = 0.54; p less than 0.003), meaning that the lower the baseline value, the greater the increase with treatment. The changes were not different when subgroups of medicated and unmedicated patients were considered separately. These results show that long-term nasal CPAP treatment results in improved left ventricular function in OSA.

Evaluation Studies as Topic↗
PubMed1991

[Postures and abnormal paroxysmal movements during sleep: hypnogenic paroxysmal dystonia or partial epilepsy?].

In recent years, a differentiation has been made between two syndromes that are characterized by brief abnormal paroxysmal movements occurring principally at night: 1, hypnogenic paroxysmal dystonia (HPD), sometimes considered a particular form of dystonia similar to paroxysmal kinesigenic choreoathetosis, and 2, mesiofrontal epilepsy. Whether HPD is a distinct syndrome is not clear. Twenty-three patients, 11 men and 12 women, were hospitalized between 1985 and 1989 for examination of this type of abnormal paroxysmal movements (APM) occurring at night. In order to clarify the physiopathology of these abnormal nocturnal movement as focal epilepsy or a particular form of dystonia, we analyzed the personal and familial antecedents of all 23 patients, the polygraphic records during waking and sleep periods, and the results of neuroradiological examinations. Four patients were examined by positron emission tomography (PET) using i8F deoxyglucose. Symptoms first appeared between 3 and 28 years of age (M, 10.1) and developed over 1 to 20 years (M, 10.1). APM clearly occurred more commonly (greater than 90%) during sleep, usually during phases of slow-wave sleep. The sleeping patient opened his eyes and the motor signs then variously associated affective facial expression; axial postural modifications; tonic, dystonic or choreic postural movements of the limbs; pedalling; automatisms; disordered agitation and vocalization. The seizure was abruptly interrupted after 10 to 60 seconds. There was usually no postictal confusion. Thirteen patients clearly had clear epileptic antecedents: in 9, generalized tonic-clonic seizures; in 4, focal epileptic status. During nocturnal polygraphic recording, 6 patients presented a generalized seizure following a period of APM.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Frequency and mechanism of daytime pulmonary hypertension in patients with obstructive sleep apnoea syndrome.

In order to study the frequency and the mechanisms of daytime pulmonary hypertension (PH) in obstructive sleep apnoea syndrome (OSAS) lung function tests, blood gas analysis and right-heart catheterization were performed in 46 consecutive patients. OSAS was assessed by polysomnography. 9 patients only (20%) had PH (mean pulmonary artery pressure (Ppa) greater than or equal to 20 mmHg). Patients with PH had lower daytime PaO2 (60.8 +/- 7.6 vs. 76.2 +/- 9.4 mmHg; p less than 0.001), higher daytime PaCO2 (44.8 +/- 4.2 vs. 38.0 +/- 4.0 mmHg; p less than 0.001), lower forced vital capacity (FVC) and forced expiratory volume (FEV1) (p less than 0.001), but the severity of OSAS was not different whether PH was present or not (apnoea index: 62 +/- 34 hour in the PH group vs. 65 +/- 40 hour, apnoea + hypopnoea index 102 +/- 33 hour in the PH group vs. 86 +/- 36 hour, lowest sleep SaO2: 59 +/- 21% in the PH group vs. 66 +/- 18%). There were significant correlations between Ppa and: daytime PaO2 (r = -0.61; p less than 0.001), PaCO2 (r = 0.55; p less than 0.001), FEV1 (r = -0.52; p less than 0.001) but not between Ppa and apnoea index, apnoea + hypopnoea index, lowest sleep SaO2. PH and daytime hypoxaemia were associated either with chronic airway obstruction or with severe obesity.

Adult↗
PubMed1990

[Changes in sleep and night respiration in asthma and obstructive or restrictive lung diseases].

Interactions between sleep and respiration have been noticed in several lung diseases. In COPD (chronic obstructive pulmonary disease) patients, the night sleep is delayed or shortened and deep sleep is often reduced or even absent. These disturbances are associated with hypoxaemic episodes occurring either in light slow wave sleep or in REM sleep, the former being short in duration and mild but repetitive and related to ventilatory changes, the latter prolonged, often severe, and resulting from both decrease in ventilation and alterations of ventilation-perfusion ratios. Restrictive syndrome due to interstitial pneumonia, kyphoscoliosis, neuromuscular diseases or, more commonly, to obesity or even pregnancy also alter sleep in a non-specific manner. Most of them result in hypoxia during paradoxical sleep. Unquestionably, there exists a relationship between sleep and asthma (aggravation of dyspnoea at night, reduction of peak expiratory flow when awaking, stage 2 asthmatic attacks). This relationship is probably caused by multifactorial interactions.

Female↗
PubMed1990

How much polysomnography is enough?

Sleep studies combined with the analysis of autonomic functions are, in several cases, necessary in order to make an accurate diagnosis. Polysomnograms require minimal technical equipment, the absence of which may cause the data obtained to be unreliable.

Humans↗
PubMed1990

Drug therapy of sleep-related hypoxaemia.

In patients with chronic obstructive pulmonary disease (COPD) exhibiting daytime hypoxaemia, a worsening of the latter occurs during sleep, particularly during REM sleep. The most efficient therapy of this sleep-related hypoxaemia is the nocturnal administration of O2 at a flow rate of 1.5-3 l/min. An alternative therapy, when daytime hypoxaemia is not too severe (PaO2 greater than 55 mmHg), is the use of almitrine (100 mg/day), a drug which improves daytime hypoxaemia in most COPD patients. The improvement of sleep hypoxaemia with almitrine is related to the increased daytime PaO2 and cannot be considered as a specific effect of almitrine on sleep-related respiratory events. It must be emphasized that almitrine is ineffective in about 25% of COPD patients ("nonresponders") and that almitrine can be used with conventional O2 therapy in patients with severe hypoxemia (daytime PaO2 less than 55 mmHg).

Almitrine↗
PubMed1990

Adrenoleukodystrophy. Value of contrast-enhanced MR imaging.

In its early stage adrenoleukodystrophy (ALD) is characterized by hypodensity at CT and signal abnormalities at RMI (low-intensity signal on T1-weighted sequences, high-intensity signal on T2-weighted sequences) in the white matter of the parieto-occipital region and the splenium of the corpus callosum. These CT and RMI abnormalities are suggestive of ALD in children with progressive alteration of the superior brain functions, but they are not specific of the disease. The authors present two cases of ALD and underline the almost pathognomonic value of contrast-enhanced ribbons found at the periphery of low-intensity signal plaques after gadolinium injection. These areas of blood-barrier disruption on a background of inflammation and active demyelination appear, on T2-weighted sequences, as ribbons of low-intensity signal within plaques of high-intensity signal. MRI is also superior to CT in detecting abnormalities located in the posterior fossa, notably lesions of the auditory fibres.

Adrenoleukodystrophy↗
PubMed1978

EMG activity of cricothyroid and chin muscles during wakefulness and sleeping in the sleep apnea syndrome.

The authors studied the direct and integrated EMG activities of the cricothyroid (CT) and chin muscles in 7 patients with the sleep apnea syndrome. They noted: (1) A tonic activity with phasic inspiratory reinforcements in the CT during wakefulness. (2) A decrease in the tonic activity without any modification of the phasic inspiratory reinforcement during sleep. (3) A decrease or even disappearance of the phasic activity during sleep-induced hypopneas. (4) A complete cessation of both the tonic and the phasic activities of the CT during obstruction apneas: resumption of respiration is marked by the reappearance first of the phasic inspiratory activity and secondly of the tonic one. (5) In some patients similar activities are recorded in the chin muscles during wakefulness, sleep and sleep apnea. These results favor possible obstruction of the upper airway at the laryngeal level: the conjunction of inhibition of the inspiratory activity of the laryngeal muscles with the subsequent closing of the glottis and inspiratory depressure could produce an obstruction.

Adult↗
PubMed1978

[Respiratory arrest during sleep. Facts and hypothyses].

The writers analyze 29 nyctohemeral recordings in 20 patients with sleep apneas. In addition to the standard polygraphy, use is made of pneumotachography and capnography. The results (central apnea with open or secondarily closed glottis; obstructive apnea with closed glottis or with expiratory valve phenomenon) raise the hypothesis of a central physiopathological mechanism common to the various types of apneas through a more or less dissociated inhibition of the activity of the respiratory, laryngeal, intercostal, and diaphragmatic muscles:--in central apnea: inhibition of the thoracoabdominal activity and maintenance of the tonicity of the laryngeal muscles, keeping the glottis open;--in obstructive apnea: persistence of the thoracic and/or abdominal activity with inhibition of the activity of the laryngeal muscles, leading to a passive obstruction due to the effect of inspiratory depression.

Airway Obstruction↗
PubMed1977

Isolation of specific messenger RNA by adsorption of polysomes to matrix-bound antibody.

A procedure is presented for the purification of specific mRNAs, which exploits the ability of antibodies prepared against a native protein to bind to the nascent polypeptide on the polysome. Rather than precipitating these soluble antibody-polysome complexes with anti-antibody, which can lead to nonspecific trapping of polysomes, we have linked the anti-antibody to an insoluble matrix. Thus, the antibody-polysome complex binds to the anti-antibody support and nonspecific polysomes can easily be removed by several washes. We have found para-aminobenzyl cellulose (PAB cellulose), to be a suitable matrix for this purpose. This support can bind large quantities of anti-antibody and it displayed no detectable nonspecific affinity for polysomes or RNA. Using this procedure, we have obtained an apparently homogeneous preparation of ovalbumin mRNA.

Animals↗
PubMed1977

Cerebral edema, mass effects, and regional blood volume in man.

The authors conducted quantitative analysis of computerized tomography (CT) scans to measure tumor size, cerebral edema, and regional blood volume in man. Mass lesions without edema caused a local reduction in blood volume. Cerebral edema also reduced blood volume in proportion to its severity. Consideration of the electrolyte changes and water shifts in white-matter edema suggested that the decrease in absorption coefficient seen in CT scans was due to the increase in water content. Thus, in cerebral edema separation of blood vessels as well as increased interstitial pressure decrease blood volume, and the regional differences in turn reflect pressure gradients within the brain.

Adult↗
PubMed1977

[Electroencephalographic study of functional metabolic encephalopathies and comas during parenteral alimentation].

This review deals with the common E.E.G. characteristics of dysmetabolic encephalopathies and described the particular features of hepatic, respiratory and renal encephalopathies, as well as those resulting from a disturbance in carbohydrate, water and electrolyte metabolism. These now classical data are compared with the principal electroclinical appearances seen during parenteral alimentation : slow, ample wases, non-reactive, associated with a calm coma; overall depression of basal rhythm, with excessive myogram activity and corresponding to paroxysms of muscular hypertonia seen during the coma.

Chronic Disease↗