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Biomedical subjects

J Krieger

Publications and source records attributed to J Krieger.

211 records · Page 12Linked to original sources
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[Polygraphic study during hyperpnea tests in elderly subjects (author's transl)].

The incidence of age on the frequency of post-hyperventilation apnea was studied in two randomly chosen distinct populations. The hyperpnea and ventilatory response were recorded during a standard E.E.G. tracing in 1 060 subjects by a thermistor and in 100 other subjects by pneumotachography and capnography. Post-hyperventilation frequency was determined for the two populations taken overall and then for subjects under and over 60 years of age. The results were compared with demographic data (sex, excess bodyweight coefficient, illness), and experimental conditions (alertness, recording technique). In the second population the mean ventilation per minute rate was calculated during a reference rest period and two successive hyperventilation tests. The frequency of post-hyperventilation apnea is higher before 60 years of age in the absence of variations in alertness and/or associated supramedullary lesions. Ventilatory response under 60 years of age is seen as a prolonged phase of hypoventilation. After 60 years of age, in the absence of apnea, ventilation returns immediately to its reference value, while in the presence of apnea the hypoventilatory phase observed is of brief duration and delayed. These results are discussed and compared to those in the published literature.

Aged↗
PubMedDate not supplied

[Respiratory changes during sleep in healthy elderly subjects (author's transl)].

The authors studied sleep organization and modifications in ventilation in 20 healthy subjects (11 men, 9 women) with an average age of 65 years. There was a diminution (in relation to young adults) in the quantity of sleep with a relative increase in light slow wave sleep and reduction in deep slow wave and REM sleep phases. A reduction was also noted in the ventilation rate during slow wave and REM sleep phases in relation to calm awake periods, especially towards the end of the night. This was due to a reduction in tidal volume insufficiently compensated by an increased ventilation frequency. Hypopnea and apnea were noted in 19 of the 20 subjects, the latter occurring in the form of obstructive apnea during light slow wave sleep. The variable number of apnea can be used to divide the subjects into two sub-groups: one group of 14 of the subjects who had less than 50 apnea; the other group containing 6 subjects, all males, having more than 80 apnea during the night, and being identical to a group of patients with the sleep apnea syndrome.

Aged↗
PubMedDate not supplied

Cloning of biogenic amine receptors from moths (Bombyx mori and Heliothis virescens).

Based on the similarity of genes which code for guanine-nucleotide binding protein- (G-protein-) coupled receptors, cDNA clones encoding new members of the receptor family have been isolated from Bombyx mori and Heliothis virescens. The deduced protein structures exhibit highest similarity to tyramine/octopamine and serotonin receptors of Drosophila. One of the receptor clones (K50Hel) was permanently expressed in the mammalian cell line LLC-PK1. In stimulation experiments its responded to octopamine leading to an inhibition of adenylate cyclase activity in a dose-dependent manner. Pharmacological studies revealed a higher affinity for mianserin than for yohimbine suggesting, that the K50Hel clone encoded a neuronal type 3 octopamine receptor. As revealed by in situ hybridization, this receptor type is expressed in the central nervous system and antennae of moth.

Amino Acid Sequence↗
PubMedDate not supplied

[A multicenter trial of a device for treating obstructive sleep apnea by continuous positive pressure].

The efficacy and tolerance of a nasal CPAP device marketed in France (Pression +, Sefam) for the treatment of obstructive sleep apnoea syndromes have been evaluated in a co-operative trial including 12 patients. This study confirmed the efficacy of nasal CPAP on sleep parameters: total sleep time was increased; light non-REM sleep was diminished; slow-wave sleep and REM sleep were augmented; sleep apnoeas were eliminated completely or almost completely; oxygen saturation was markedly improved. At one month follow-up, most clinical features were improved; daytime blood gases showed little change but the number of red cells was decreased. On the whole, the tolerance was good in this highly motivated group of patients: eleven patients (92%) were willing to continue their home treatment with the same device. Most difficulties were due to the making of a tailored molded nasal mask and its use during sleep.

Adolescent↗
PubMedDate not supplied

[Value of sleep polygraph examination in the etiological diagnosis of apparently inexplicable respiratory insufficiency].

This study describes the case of a 58 year old man who presented with an episode of acute respiratory failure and right heart decompensation. After recovery from the acute illness, hypoxaemia, hypercapnia and pulmonary arterial hypertension remained, the causes of which were not known. There was no airway obstruction, only a moderate restrictive ventilatory defect, a little weight increase and a unilateral diaphragmatic paralysis. Obstructive sleep apnoea was finally suspected and confirmed by sleep recording. The obstructive sleep apnoea probably explained the respiratory insufficiency and the pulmonary hypertension. Loss of weight was associated with the disappearance of hypercapnia and pulmonary hypertension. As a result of this study, the value of sleep recording is emphasized. When respiratory failure or pulmonary hypertension seem unexplained, think of obstructive sleep apnoea.

Humans↗
PubMedDate not supplied

Effects of pneumotachographic recording of breathing on sleep and respiration during sleep.

Pneumotachographic recording of ventilation requires an air-tight nasobuccal face-mask which might disturb the subjects' sleep and modify their breathing patterns. In a cross-over randomized study, we compared recordings obtained with and without a face-mask in 20 healthy normal volunteers (10 males, 10 females, mean age: 21.7 +/- SEM 0.5 years). The sleep modifications that resulted from the presence of the face-mask were a lengthening of the REM-sleep latency (+ 38%, p less than 0.01), an increase in intrasleep waking-time (+ 55%, p less than 0.05), an increase in sleep stage-1 duration (+ 40%, p less than 0.02), and a decrease in REM-sleep duration (-20%, p less than 0.01), resulting in a decrease in total sleep duration (-9%, p less than 0.05). The sleep-latency, the number of awakenings, the sleep stage-2 duration, the deep slow wave sleep duration, the sleep stability and the number of sleep cycles were not significantly modified. The respiratory frequency was unchanged in any of the sleep stages. No obstructive or mixed apnoea was observed during the nights when the subjects wore the face-mask. The apnoea index for central apnoeas was low and remained unchanged with and without the face-mask (0.30 +/- 0.10 and 0.35 +/- 0.10 respectively). Thus the observed modifications do not rule out the basic advantage of the pneumotachographic method, that of being the only method to-date providing a direct quantitative measurement of respiratory flow and flow rate during sleep.

Adult↗
PubMedDate not supplied

Evaluation of oral rehydration therapy in Matiguas, Nicaragua.

Use of oral rehydration salts is an effective tool to decrease deaths due to diarrheal dehydration. Following concerted educational efforts to introduce oral rehydration therapy, Nicaragua reported a significant decrease in deaths of young children from diarrhea and dehydration over a 5-year period. Further decline in the mortality rate has not occurred, however, and factors that would affect usage and impact are poorly understood. A health survey was administered in 155 randomly selected homes in Matiguas, Nicaragua, in July 1990. Caretakers of children were asked about their knowledge, attitudes, and practices in treating diarrhea in children younger than age 5. They were also asked to demonstrate their knowledge of mixing World Health Organization oral rehydration salts packets. Ninety percent of the respondents said they used oral rehydration therapy. The major reason quoted for not using it was dislike of the taste. Of the three-quarters willing to mix the oral rehydration salts, 62 percent prepared the solution correctly and 38 percent incorrectly. Knowledge about diarrhea and the role of oral rehydration therapy was high in this population, and those with this knowledge were more likely to use it. Respondents who learned to mix the oral rehydration salts at the health center had more years of education and were more likely to mix the salts correctly. In this study, there is a positive association between contact with the health center and correct use of the rehydration salts. The relationship of this association with morbidity and mortality needs further research.

Adolescent↗