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Biomedical subjects

C Popow

Publications and source records attributed to C Popow.

At least 55 records · Page 3Linked to original sources
PubMed1985

Regional heat loss in newborn infants. Part II. Heat loss in newborns with various diseases--a method of assessing local metabolism and perfusion.

Heat flux (HF) from the head, trunk and limbs of 6 neonates with various abnormalities was measured with HF transducers to find out whether the regional HF pattern reflected the metabolic and/or circulatory status of a neonate, his brain or limbs sufficiently to be of clinical use. The increased HF from all body sites in 2 infants receiving orciprenaline reflected the raised metabolism. The increased HF from the head and trunk together with decreased HF from the limbs in infants with the hypoplastic left heart syndrome reflected the degree of centralization of the circulation. The decreased HF from the head of infants with microcephalus and internal hydrocephalus indicated the diminished metabolic activity of the underlying brain. HF from the limbs, related to HF from central body parts, was useful in assessing peripheral perfusion. It might be possible to develop measurement of regional HF into a method of determining local metabolism and perfusion.

Body Temperature Regulation↗
PubMed1984

Comparison of chest radiography and static respiratory compliance in the assessment of the severity of pulmonary diseases in newborns with respiratory distress.

In 55 newborn infants with respiratory distress syndrome (RDS) we compared chest radiographs and static respiratory compliance to see which of the two methods would best characterize the severity of pulmonary disease. There was a significant correlation between radiological score and compliance (rs = -0.5776, n = 55, p less than 0.001). Healthy newborns, newborns with RDS who did not need artificial ventilation and those newborns who needed respirator treatment had significantly different values of radiological score and compliance. RDS may be differentiated into groups of diagnoses. Newborns with HMD could be separated from those with wet lung syndrome or aspiration pneumonia by analyzing the radiogram or measuring the compliance. When survivors are compared with those newborns who died, the static respiratory compliance alone could predict the final outcome.

Humans↗
PubMed1983

[lst report: Alternatives to cortisone therapy. lst clinical experiences with a carnitine-betamethasone combination for the stimulation of fetal lung maturity].

In the recent past criticism has been voiced with regard to the efficacy and possible side effects of corticosteroid prophylaxis of fetal respiratory distress syndrome (RDS). Apparently the efficacy of this treatment has been over-estimated and the spectrum of possible side effects has not received enough critical attention. In view of the multiple indications that the fetal metabolism, above all, may be altered by this type of therapy, it seems necessary to search for other methods of surfactant stimulation. This paper presents the first clinical study on the use of carnitine (4 g for 5 days in combination with twice 8 mg beta-methasone versus twice 8 mg betamethasone alone). The patients on combination therapy showed a more marked increase in surfactant content of the amniotic fluid. Lung compliance determination in infants born within 72 hours of completion of therapy also revealed better results in the combination therapy group. There were also fewer clinically demonstrable RDS cases in this group. More research will be necessary to definitely establish the value of this new form of therapy.

Animals↗
PubMed1983

Gentamicin monitoring in low-birth-weight newborns.

The pharmacokinetics of gentamicin in premature newborns is influenced by many noncalculable variables. Nevertheless, and despite its narrow therapeutic range, this aminoglycoside antibiotic is usually prescribed according to a fixed schedule. Gentamicin was monitored in 22 severely sick, low-birth-weight newborns on combination therapy of various antibiotics including gentamicin. Dosage regimen of gentamicin was prescribed according to Eichenwald and McCracken [1978]. Serum gentamicin concentrations were measured by radioimmunoassay before infusion, 30 min after, and 3 h after infusion of the antibiotic. In 22 prematures desirable serum gentamicin concentrations with a mean elimination half-life (t 1/2) of 5.3 h; in 2 prematures, levels with a mean t 1/2 of 2.3 h; in 7 prematures, possible toxic levels with a mean t 1/2 of 8.3 h; and in 2 prematures, definite toxic levels with a prolonged t 1/2 up to 17 h were observed. Most of the prematures with possible or definite toxic gentamicin levels were not older than 1 week. This is explained by the immaturity of the kidneys and the retention of aminoglycosides. A satisfactory correlation between postnatal age and gentamicin elimination half-life was found, which might be caused by postnatal maturation of the glomerular function. In prematures in the 1st postnatal week we recommend reducing the daily dose by prolonging the dosage interval, e.g., from 12 to 18 h, or reducing the single gentamicin doses. Gentamicin monitoring seems advisable for detecting toxic serum concentrations and accumulation and for revealing an insufficient dosage of this aminoglycoside antibiotic.

Age Factors↗
PubMed1982

[The determination of oxygen consumption from temperature measurements with the use of a thermodynamic model ].

A thermodynamic model is described which allows to calculate the oxygen consumption from 4 temperatures as input-variables. These input-variables are: one core-temperature (Tesoph), two skin-temperatures (one at the chest, one at the calf) and the incubator-air temperature. This model is based on the close relationship between oxygen consumption and heat production. The rate of heat production is derived from heat loss to the environment plus heat storage in the body. The data are smoothened by a special mathematical procedure and processed by a HP-85 Computer. Oxygen consumption was synchronously determined by the thermodynamic model and by a conventional method 155 times in four newborns. The flow-through method was used as conventional reference method. The results show that the thermodynamic model yields values for oxygen consumption which are closely related to directly measured values; which indicate the increase in oxygen consumption with activity and decreased environmental temperature; and which follow rapid changes in oxygen consumption of 5 ml/kg per minute. Consequently this thermodynamic model seems suitable to predict the relative changes in oxygen consumption. However the absolute values of oxygen consumption obtained by the model and obtained by direct measurement differ by 5 to 25% the thermodynamic model yielding systematically higher values than the direct measurement. The reasons for this difference are discussed. We demonstrated that a maximum of reliable information can be obtained from a minimal number of measuring sites on the patient by using a theoretical-analytical model.

Body Height↗
PubMed1982

[Glucose disposal in very low birth weight infants ].

Glucose disposal was studied in six very low birth weight infants (birth weight 1093 +/- 67 g (M +/- SEM), gestational age 29.8 +/- 0.6 weeks, postnatal age 5.2 +/- 0.9 days) by constant infusion steady state technique. All babies required artificial ventilation because of respiratory distress syndrome (four) or aspiration pneumonia (two). Nine healthy prematures of comparable birth weight, gestational age, and postnatal age formed the control group. During a constant glucose infusion at a rate of 8 mg/kg/min (7.7 +/- 0.2) mean blood glucose levels of the sick infants were higher than the corresponding control values. All sick babies had glycosuria (glucose excretion 34 +/- 19 mg/kg/hr compared to none of the controls 0.8 +/- 0.2, p less than 0.01). Glucose disposal in the sick prematures was significantly decreased in comparison to the healthy infants [92.6% (78.7 to 99.3%) of input rate vs. 99.8% (99.7 to 99.9%), p less than 0.01]. It is concluded that sick very low birth weight infants tend to develop hyperglycemia, glucosuria, impaired glucose disposal, and renal caloric wasting when exogenous glucose is supplied at a rate of 8 mg/kg/min, which is usually well tolerated by healthy prematures.

Blood Glucose↗
PubMed1982

[Thyroid function in healthy premature infants and in premature infants with the hyaline membrane syndrome ].

The serum concentrations of thyrotropin (TSH), thyroxine (T4), trijodothyronine (T3) and of 3,3',5', trijodothyronine (reverse T3, rT3) were followed up during the first 4 weeks of life in 5 healthy premature infants and in 6 premature infants with hyaline membrane syndrome and artificial ventilation. TSH and T4 concentrations remained unchanged in both groups. T3 levels increased during the observation period and were significantly lower in the sick prematures on days 1 and 3 (p less than 0,02). T3 and the rT3/T3 ratio was increased in healthy and in the sick prematures, the sick prematures showing higher values, and decreased in both groups during the first week of life. We found no significant correlation between TSH and the peripheral thyroid hormone levels as well as no relation between the respiratory compliance-indicating degree of lung maturity-and the T3 or T4 concentrations. Postpartal T3 or T4 serum levels were correlated significantly with the duration of artificial ventilation. Our data indicate that a "low T3 syndrome" was present in all prematures after birth and that respiratory distress syndrome increased conversion of T4 to rT3. From our results we cannot conclude that substitution therapy with thyroid hormones may be useful in premature infants with the hyaline membrane syndrome.

Humans↗
PubMed1982

[Respiratory mechanics and respiratory regulation in healthy and respiratory-diseased newborn infants of different gestational ages].

The interaction of lung mechanics, peripheral lung reflexes and chemosensitivity of the respiratory center were studied in over 80 newborns. Healthy newborns (gestational age between 30 and 41 weeks) and newborns with respiratory distress syndrome (RDS) (gestational age between 29 and 40 weeks) were studied on the first day of life. Spontaneously breathing newborns were examined using the airway occlusion technique (AOT), and intubated babies using the injection technique (IT) to measure the compliance of the respiratory system (Crs), the strength of the inspiration inhibiting reflex (IIR) and inspiratory time during airway occlusion (Ti occ), and index of chemosensitivity of the respiratory center. Crs in healthy newborns increased only slightly but statistically significant (p less than 0.001) with gestational age. Crs of newborns with RDS had an overwhelming influence on their prognosis. Newborns with Crs of less than or equal to 1 developed respiratory failure and needed ventilatory support. Newborns with a Crs less than or equal to 0.5 died despite respiratory therapy. The activity of the peripheral vagally mediated reflex system also depended on the Crs. Our results indicate that the decrease in reflex activity with gestational age is not brought about by neurologic maturation but is caused by the increasing Crs. We conclude that the peripheral vagally mediated reflexes remain the same throughout life, just the boundary condition Crs, which is given by the lung mechanics, is different for premature or mature newborns and changes with age. The chemosensitivity of the respiratory center for CO2 was characterized by the inspiratory time after an expiratory occlusion (Ti occ) which is not influenced by lung mechanics. Ti occ correlated significantly with pCO2. The relation between Ti occ and pCO2 was similar for premature and mature, healthy and respiratory ill newborns. Consequently, chemosensitivity, expressed as the ratio of Ti occ and pCO2, is independent of gestational age.

Carbon Dioxide↗
PubMed1982

[Determination of serum concentrations of aminoglycosides in the monitoring of therapy in neonates. I. Gentamycin].

We studied the serum concentrations of gentamicin by radio-immuno-assay in 22 sick prematures (birth weight 1713 +/- 469 g, prenatal age 33 +/- 3 weeks, postnatal age 12 +/- 9 days) receiving 2.5 mg/kg bid. Bactericidal concentrations were present in 91% but only 50% had normal serum concentrations and gentamicin half-lives. Gentamicin half-life decreased significantly (p less than 0.01) with postnatal age but there was no statistically significant correlation between gentamicin serum concentration and gestational age or birth weight. We therefore recommend 1. gentamicin serum concentrations to be monitored routinely in therapy of prematures especially in the first week of life, 2. to expand the dosage interval up to 18 hours (which is about the threefold half-life) in prematures during the first week of life.

Gentamicins↗
PubMed1982

[Diagnosis, treatment and follow-up of a patient with pseudohypoaldosteronism (author's transl)].

We report about a girl, 22 months old, with pseudohypoaldosteronism. The clinical course was characterized mainly by renal salt loosing syndrome, complicated by suddenly occurring hyperkalemic phases and a complete inability of renal electrolyte and acid-base regulation. Congenital adrenal hyperplasia was excluded and the diagnosis based on renal salt wasting despite hyperaldosteronaemia and increased plasma renin activity. Diagnosis and therapy of pseudo-hypoaldosteronism are discussed as well as the problems of long-term oral sodium chloride substitution and long-term therapy with sodium-polystyrol-sulfonate, a cation-exchange resin.

Acid-Base Equilibrium↗
PubMed1981

[Exercise-induced asthma (EIA) and radioallergosorbenttest (RAST) (author's transl)].

38 children with bronchial asthma were investigated for allergy (RAST), non-specific bronchial hyperreactivity (acetylcholine challenge) and reaction to physical exercise (free running and bicycle ergometry). 17 patients showed EIA caused by free running and 11 by cycloergometry. Patients with clear-cut allergy (n = 27, high RAST values, class 3 and 4) showed exercise-induced bronchoconstriction in a high percentage of cases (16 of 27 following running, 10 of 27 after bicycle ergometry). Such patients also had non-specific bronchial hyperreactivity. This would explain treatment failures after correctly performed specific immunotherapy.

Acetylcholine↗
PubMed1981

[Shortening of interval between first and second TBE vaccination in asthmatic children (author's transl)].

37 children suffering from asthma had to be vaccinated against tick-borne encephalitis (TBE) with an interval of only 10 days between the first two vaccinations. Sufficient antibodies were detected in samples taken 14 days after the second injection. No differences were found between the results in this group of asthmatic children and in children who were vaccinated with the usual interval of 1 to 3 months elapsing between the first two injections. The asthmatic children tolerated the vaccination very well, moreover the indicence of side reactions was not different from that of the control group.

Adolescent↗