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Biomedical subjects

C Simon

Publications and source records attributed to C Simon.

At least 379 records · Page 21Linked to original sources
PubMed1976

[Azidocillin: activity in vitro, pharmacokinetics and therapeutic results in whooping cough].

In vitro activities of acidocillin and ampicillin were compared in 20 strains of Haemophilus influenzae, 50 strains of Enterococci and 4 strains of Bordetella pertussis by serial dilution test. There were no significant differences between both antibiotics. On Staphylococcus aureus (100 strains) and Streptococcus group A (25 strains) acidocillin was effective at the same degree as phenoxymethylpenicillin. After oral administration of 0.75 g acidocillin (1 h after a standard breakfast) serum peaks in 10 healthy adults were 6.1 +/- 0.51 mug/ml (after 1 1/2 h) which decreased to 0.5 +/- 0.10 mug/ml (after 4 h) and to 0.045 +/- 0.02 mug/ml (after 6 h). Urine-recovery in 9 h after oral administration of 0.75 g was found as of 58%, after i.v. administration of the same dose 78% (absorption rate nearly 74%). Therapy of whooping cough in 12 children with acidocillin (60 mg/kg/die) led to the disappearance of Bordetella pertussis from nasal swabs (only one failure caused by the child's frequent vomiting).

Administration, Oral↗
PubMed1976

[Activity in vitro and pharmacokinetics of minocycline (author's transl)].

The in vitro activity of doxycycline and minocycline (Klinomycin) was determined by serial dilution test in 100 strains of E. coli, 101 strains of enterobacter, 91 tetracycline-sensitive and 52 tetracycline-resistant strains of staphylococci. Only staphylococci were more sensitive against minocycline than against doxycycline whereas other species showed nearly the same sensitivity against both antibiotics. After i.v. infusion of 200 mg minocycline (during 1 h) mean serum levels fell from 3.5 mug/ml to 0.6 mug/ml (after 24 h). Half-life was calculated as 15.7 h, urine recovery as 5.9%. After oral application of 200 mg minocycline serum level peaks were 2.7 mug/ml, serum levels after 24 h 0.7 mug/ml. At repeated administrations daily dosage of 100 mg was too low of 200 mg sufficient to obtain the same serum levels as after the initial dose of 200 mg. CSF levels after oral administration of 0.4 g minocycline were 0.74 +/- 0.09 mug/ml (in serum at the same time 2.2 +/- 0.2 mug/ml). Half-life of minocycline in chronic renal failure (7 adult patients) was not prolonged (15--20 h). Minocycline is especially suitable for treatment of infections of unknown bacterial origin (including such caused by staphylococci). I.v. infusion is indicated only in unconscious or vomiting patients.

Administration, Oral↗
PubMed1975

[Cerebral vasoparalysis, arterial hypertension and brain edema (author's transl)].

The present studies were performed in order to determine whether "filtration edema" will develop as a consequence of cerebral vasoparalysis, vasoparalysis in combination with arterial hypertension or arterial hypertension alone. A series of dogs, anaesthetised with i.v. Chloralose-Urethane were exposed 1) to cerebral vasoparalysis, produced by hypercapnia (PaCO2 about 150 mm Hg) and hypoxaemia (PaO2 40-60 mm Hg); 2) to arterial hypertension and 3) to a combination of cerebral vasoparalysis and arterial hypertension. Following cerebral vasoparalysis and arterial hypertension, a significant decrease of total cerebrovascular resistance and moderate increase of venous resistance was observed. Regional cerebral blood flow (133Xe), intracranial pressure, as well as the pressure in postcapillary venous outflow (sinus sagittalis wedge pressure and confluence sinuum pressure) were increased. Neither normotonic vasoparalysis nor vasoparalysis in combination with slight arterial hypertension (MABP more than 90 min above 180 mm Hg) resulted in cerebral edema. In contrast, cerebral vasoparalysis in combination with severe arterial hypertension (MABP more than 90 min above 220 mm Hg) resulted in a statistically significant increase in the water content in the white matter without evidence of protein extravasation. Multiple small foci of Evans blue extravasates, however, were found in the cortex following arterial hypertension in combination with vasodilation, indicating a damage of the blood brain barrier. In these blue stained cortical areas the water content was significantly in creased. The following conclusions were drawn from the results. Vasoparalysis during normotension does not produce brain edema despite the slightly elevated hydrostatic pressure gradient between intravasal and extracellular space. Only considerable increase of this hydrostatic pressure gradient caused by a combination of vasoparalysis with severe arterial hypertension is able to produce brain edema in the white matter. In addition, acute hypertension may cause minor multifocal damage of the blood brain barrier in the cerebral cortex. It is concluded that so-called brain swelling, which has been described by several authors in states of cerebral vasoparalysis, is not predominantly caused by brain edema but by vascular congestion. The clinical aspects of the result are discussed.

Animals↗
PubMed1975

[The pharmacokinetics of doxycycline in kidney insufficiency in geriatric patients compared to younger adults].

In young adults i.v. injection of 200 mg doxycycline was followed by a rapid fall in serum levels in the first 30 minutes and than a slow decrease (serum concentration after 24 h on average 1.0 mug/ml). Biological half-life was 11.9 h, final distribution volume 50.0 litres and urine recovery 70%. After oral administration of 200 mg doxycycline the serum peaks measured were 3.4 mug/ml (2 1/2 h later). With repeated doses of 100 mg every 24 h serum peaks were 2.8 mug/ml and serum concentrations after 24 h 0.8-0.9 mug/ml (urine recovery 43%). The area under the curve was 25.5% less than after i.v. injection. In 7 adults with chronic renal failure the half-life of doxycycline varied between 10 and 24 h. With repeated oral administration of doxycycline (100 mg every 24 h) there was no accumulation of the drug in blood. During hemodialysis (Stuttgart kidneys, Rhône-Poulenc plates) doxycycline injected i.v. was eliminated as rapidly as before. In renal failure doxycycline may be given in the same dosage as where renal function is normal. In 12 geriatric patients without renal disease, serum levels of doxycycline after i.v. injection of 200 mg were not significantly different from those of young adults (distribution volume 46.2 +/- 16.2 litres). It can therefore be assumed that tissue penetration of the drug is similar in the elderly and in young adults.

Administration, Oral↗
PubMed1975

[Bimodal secretion of thyroid hormones].

In rats receiving 50 mug of iodine daily, the turnover curve of plasmatic hormones is bimodal. Simultaneously, a flux of direct secretion and a flux of delayed secretion participate in the hormonal secretion. The second flux is about twenty times greater than the first one. The delay of its turnover is probably due to the diffusion of the molecules of thyroglobulin into the colloid.

Animals↗
PubMed1975

[Isotopic equilibrium and thyroid secretion].

The long-term iodine turnover (140 days) of thyroid gland and plasma has been studied in rats in a steady state and receiving either 5 (group 5) or 50 (group 50) mug of iodine daily. At 60 days, the turnover of Thyroglobin is total (group 50) or 80% (group 5) but is total for PBI in the two groups. An iodine pool with a very slow turnover participates neither in the PBI secretion nor in the iodide recycling within the gland.

Animals↗
PubMed1975

[Bioavailability of different brands of phenoxymethylpenicillin (author's transl)].

The bioavailability of 11 brands of phenoxymethylpenicillin was investigated in a cross-over-study in healthy volunteers. There were found some differences in the velocity of absorption, in the peaks and in the blood levels after 4 hours. The absorption rate was evaluated by comparison of area under the curve and urine-recovery after oral administration of different brands. It is suggested to control each brand of oral antibiotic preparations on bioavailability.

Administration, Oral↗
PubMed1975

[Pneumonia as a cause of death in children (author's transl)].

The yearly death-rate from pneumonia in children aged one month to 15 years has fallen in Schleswig-Holstein from 1.8 (1954-1958) to 0.6 per ten thousand (1969-1973). At the same time, total death-rate in the same age group has fallen from 14.5 to 9.3 per ten thousand children. The proportion of pneumonia in the total death-rate was 5.3% in 1971-1973, 1.6% in the first month of life and, after the sixteenth year, 2.3%. Pneumonia was in fourth place (after accident, malformation and neoplasm) as a cause of death in those more than one month old. The death-rate due to pneumonia had not fallen between 1954 and 1973, varying between 10% and 12%. While death-rate of "primary" pneumonia (without other underlying disease) had fallen from 5.7% (1954-1958) to 1.1% (1969-1973), the death-rate of "secondary" pneumonia rose from 16.8% to 21.4% during the same period. The total number of children aged between two months and 15 years treated for pneumonia fell by two thirds from 1954-1973 (1245 to 406). The incidence of "primary" pneumonia during the same period fell to about a quarter, that of "secondary" pneumonia to one half. The unsatisfactory result in the treatment of "secondary" pneumonia is probably due to the underlying primary disease or a weakening of defence mechanisms by treatment or the occurrence of unusual causative organisms (pneumocystis carinii, tubercle bacilli, Candida, Aspergillus), demonstrated only after death.

Adolescent↗
PubMed1975

Iodinated particles in the rat thyroid. II. Lysosomal characteristics.

In a previous study (Simon et al. 1971) a procedure for the preparation and separation of iodinated particles was described in the rat. The present paper deals with further investigations on the nature of these particles. Acid phosphatase and iodine are conjointly sedimentable and display a latency that is unmasked on dilution in a hypo-osmotic medium and under acidification to pH 5.0. These properties together with the sensitivity to Triton X-100 are best accounted for by assuming that iodinated particles of the thyroid gland are lysosomes. Part of the particulate iodine is soluble in n-butanol (BEI fraction). The existence of this BEI fraction demonstrates that hydrolysis of thyroglobulin occurs within the particles which thus exhibit an acid protease activity. Both the sedimentable iodine pool and acid phosphatase are increased under TSH stimulation and decreased after thyroxine treatment. In addition, the general activity of the iodinated particles is dependent on the daily iodine intake as shown by the variation of their iodine pool, acid phosphatase activity and BEI fraction with the iodine diet. It is concluded that iodinated particles of the thyroid gland are secondary lysosomes which participate in iodine secretion under TSH control. By in vitro treatment with destabilizing media or after in vivo treatment with thyroxine, iodinated particles exhibit a parallel loss of iodine and acid phosphatase. After a short-term TSH treatment in vivo, their iodine pool is more increased than their acid phosphatase activity. It is concluded that, at least in the normal rat thyroid, iodinated particles are essentially secondary lysosomes; true colloid droplets actually accumulate only after sufficient TSH stimulation.

Acid Phosphatase↗
PubMed1975

[Antibiotics in newborns and young infants].

Localized and generalized infections in newborns nowadays are mostly due to gram negative bacteria (E. coli, Klebsiella, Enterobacter, Pseudomonas pyocyanea, Serratia marcescens et al.). Unspecific treatment causes an increasing rate of resistance, as shown by an account of our own experiences. Tobramycin, Gentamycin, and Cefazolin appear to be particularly promising antibiotics to avoid the development of resistance though their pharmacokinetics in the newborn have to be considered carefully. Based on the determination of serum levels of Tobramycin and Amoxycillin in newborns general recommendations for the dosage of these new antibiotics are given.

Adult↗