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Biomedical subjects

H Bartels

Publications and source records attributed to H Bartels.

At least 217 records · Page 12Linked to original sources
PubMed1979

Acclimatization of newborn rats and guinea pigs to 3000 to 5000 m simulated altitudes.

Two species of newborn rodents (guinea pigs and rats) were acclimatized to simulated altitudes of 3000 to 6000 m during 2 to 8 weeks after birth. Body weight increase was significantly retarded in both species at altitudes of 5000 m and higher. Heart weight relative to body weight increased by 50% at 3000 m and 300% at 5000 m (after 7 weeks) in rats but was only 17% increased even at 5000 (6 weeks) in guinea pigs. Relative lung weights increased by 40% at 3000 m in rats and 5000 m in guinea pigs; at 5000 m rats showed a 130% increase. Hb-concentration increase (20%) was not significantly different in rats at 3000 m and 5000 m, respectively, in guinea pigs it was below 10% at 3000 m and around 40% at 5000 m. Half saturation pressures of blood (P50) increased in rats significantly compared to controls but not in guinea pigs. The results suggest that relative maturity and high blood oxygen affinity in newborn guinea pigs favor high altitude acclimatization. Immaturity of newborn rats, their low blood oxygen affinity and immature enzyme patterns are considered as reasons for the smaller resistance against high altitude stress compared to guinea pigs.

Acclimatization↗
PubMed1979

Flow-dependent salivary primidone levels in epileptic children.

In 36 epileptic children treated with primidone alone or in combination with additional anticonvulsants, salivary drug levels were compared in resting (I) and in flow-stimulated (II) saliva and were related to the corresponding serum levels. Primidone levels in saliva I and saliva II were highly correlated (r = 0.97) but were significantly (p less than 0.001) lower in saliva II; the mean difference was -38%. Serum primidone levels were highly correlated to salivary primidone levels both in saliva I (r = 0.92) and in salvia II (r = 0.91). A significant negative correlation could be established between the salivary flow rate and the saliva/serum ratio of primidone, especially in saliva I (r = 0.61; p less than 0.001). The mean saliva I/serum ratio was 1.115, reflecting drug accumulation in resting saliva. The reason primidone accumulates remains unclear. When salivary flow was stimulated, the mean saliva/serum ratio decreased to 0.7, indicating the development of a drug concentration slope from blood to saliva. This is explained by the limited permeation of the drug through cellular membranes due to its rather low lipid solubility. From the data it can be concluded that saliva is suitable for monitoring primidone levels provided the conditions of sample collection are standardized.

Anticonvulsants↗
PubMed1979

Blood oxygen transport and organ weights of two shrew species (S. etruscus and C. russula).

Blood parameters concerning oxygen transport and relative organ weights of 11 Suncus etruscus and 13 Crocidura russula under light halothane anesthesia were investigated. Mean body weight of S. etruscus was 2.5 g and for C. russula was 9 g, hemoglobin concentration was 17.4 and 15.6 g/100 ml blood, hematocrit was 50 and 44%, red blood cells were 18 and 11 X 10(6)/microliter, respectively. Mean corpuscular volume was calculated to be 26 and 41 micron3, mean diameter 5.5 and 7 micron, and mean thickness 1.2 and 1.1 micron, respectively. Mean corpuscular hemoglobin concentration was in the normal range of mammalian red blood cells. A blood oxygen half-saturation pressure of 35 and 34 Torr at pH 7.4, 37 degrees C and a Bohr factor deltalog P50/deltapH of -0.61 and -0.66 was measured. Experiments with stripped hemoglobin showed that 2,3-diphosphoglycerate is the main oxygen affinity reducing allosteric factor. Relative weights of heart, kidney, and liver are remarkably high in S. etruscus. The maximal oxygen transport of 400 ml . kg-1 . min-1 of S. etruscus is feasible by an enormous heart rate, a large relative stroke volume, a high hemoglobin concentration combined with a low oxygen affinity, and a large Bohr effect.

Animals↗
PubMed1978

[Respiratory function of blood and relative weight of certain organs in two species of shrew: Crocidura russula and Suncus etruscus (Soricidae mammals)].

A high oxygen capacity combined with a low oxygen affinity and a large Bohr effect achieve a high oxygen transport capacity in small shrews. The high metabolic rate (Suncus estruscus: 100 to 350 ml O2/kg. min) can be explained by the combination of the favorable blood parameters with a high relative heart weight (1,2% of body weight) and heart frequencies of 1,000 to 1,350 per minute.

Animals↗
PubMed1978

Regulation of oxygen affinity in blood of fetal, newborn and adult mouse.

Oxygen half saturation pressure (P50) of blood and the role of 2,3 diphosphoglycerate (DPG), adenosine-triphosphate and red cell pH regulating oxygen affinity were examined in fetuses (16,5-18,5 days of gestational age), neonatal (1-22 days post partum) and adult mice (Balb/c). The high oxygen affinity of fetal blood (P50 = 29 Torr at 37 degrees C, pH 7.4 and Pco2 = 40 Torr) decreases to an average adult value of 41 Torr within two weeks after birth, accompanied by an increase of DPG-concentration from 0.2 M/MHb4 to the average of 1.5 M/MHb4. At a constant pHe of 7.4 red cell pH decreases from pH 7.3 to 7.18 from 18.5 days of gestational age to ten days post partum. Electrophoretic mobility and functional characteristics of purified fetal and adult hemoglobin were identical. Changes in oxygen affinity occur only due to organic phosphate concentration variations. A rapid replacement of large size fetal red cells by smaller adult cells after birth fairly coincides with the increase of the 2,3-DPG concentration.

Adenosine Triphosphate↗
PubMed1978

Discrimination between human T and B lymphocytes and monocytes by computer analysis of digitized data from scanning microphotometry. I. Chromatin distribution patterns.

Digitized images of Feulgen-stained normal human B and T lymphocytes and monocytes were analyzed by computer and microphotometry. The algorithms assessed the chromatin distribution patterns. A substantial number of parameters descriptive of the chromatin distributions were found to show statistically highly significant differences between B and T cells and monocytes. Although the effects of a number of biologic variables, such as cell cycle phase and immune stimulation, need to be carefully evaluated, the preliminary results indicate potential for automatic classification and subclassification of human B and T lymphocytes in normal and disease states.

Adult↗
PubMed1977

Serum alkaline phosphatase isoenzymes in epileptic children receving anticonvulsant drugs.

In 40 epileptic children on long-term anticonvulsant treatment, serum alkaline phosphatase (AP) isoenzymes were separated semiquantitatively using a combination of L-phenylalanine inhibition and heat inactivation. Though mean total serum AP activity was significantly increased compared to age matched controls, only 4 individual values exceeded the upper limit (mean + 2SD) of the reference sample. In epileptics the mean activity of the heat-sensitive non L-phenylalanine sensitive AP fraction (non-LPSAP) was significantly increased (P less than 0.01) and the mean Q-value (i.e. percentage ratio of heat-stable non-LPSAP/non-LPSAP) was significantly decreased (P less than 0.05), thus indicating an enhancement of the bone isoenzymes during anticonvulsant treatment. In 4 patients the isoenzyme pattern was abnormal although total serum AP activity was normal and in 3 of them the deviation indicated enhanced bone isoenzyme. The data provide evidence that in anticonvulsant treated children the bone isoenzyme, rather than hepatobiliary isoenzyme fraction, may be increased even when total serum AP activity is normal. Thus, semiquantitative separation of serum AP isoenzymes may be a helpful guide as to whether or not an eplieptic child should be given vitamin D.

Adolescent↗
PubMed1977

[Treatment of cerebrovascular insufficiency. A double blind trial of Cetal retard against cinnarizine (author's transl)].

The results of a double blind trial in a total of 54 outpatients with cerebrovascular insufficiency are reported. With reference to objective test criteria (flicker frequency analysis and reaction test) and the change in the existing symptoms of this clinical picture the behavior of a new preparation, Cetal retard, was compared with the well-known drug (cinnarizine) with regard to the therapeutic efficacy on these symptoms. Although a therapeutic success was demonstrable in both groups after 21 days, Cetal retard was found to be significantly better in a number of the criteria tested.

Aged↗
PubMed1977

Use of saliva in monitoring carbamazepine medication in epileptic children.

In 17 children on carbamazepine medication alone and 15 children on combined drug regimens, carbamazepine levels were determined in paired samples of serum and mixed saliva by enzyme immunoassay. Carbamazepine levels in serum and saliva were highly correlated in within-patient and between patient series (r = 0.87--0.94). Salivary levels were altered to a minor and clinically insignificant degree by stimulation of saliva flow. Mean saliva/serum ratios, calculated from drug concentrations in saliva specimens collected without and with stimulation were 0.44--0.45 and 0.41--0.43, respectively. The saliva/serum ratio was independent of the serum carbamazepine level and was not affected by concomitant drug medication. The data indicate that measuring salivary levels by enzyme immunoassay is suitable for predicting serum carbamazepine levels. Thus, measurement of carbamazepine levels in mixed saliva samples obtained by a noninvasive technique is recommended for routine monitoring of carbamazepine medication in epileptic children.

Carbamazepine↗
PubMed1977

Serum alkaline phosphatase isoenzymes in childhood.

Using a combination of L-phenylalanine inhibition and heat inactivation, the serum alkaline phosphatase (AP) in 2 to 13 year old children without evidence of hepatobiliary, osseous, or intestinal disease was separated in three fractions; i.e. L-phenylalanine sensitive AP (LPSAP), heat-stable non-L-phenylalanine sensitive AP (heat-stable non-LPSAP) and heat sensitive non-L-phenylalanine sensitive AP (heat-sensitive non-LPSAP). The activities of total AP and the different fractions were measured using optimized test conditions. LPSAP, (mainly intestinal AP), accounts for approximately 12% of the total serum AP activity, heat-stable non-LPSAP (mainly hepatobiliary AP) for approximately 9%, and heat-sensitive non-LPSAP (mainly bone AP) for approximately 77%. To give a better differentiation between bone and liver AP, the percentage ratios of heat-stable non-LPSAP/non-LPSAP (Q value), and heat-stable non-LPSAP/total AP, were determined. Both quotients showed a significant negative correlation with total AP, which has to be taken into account in the interpretation of the results of isoenzyme determinations of serum AP activity. The above semiquantitative separation of AP isoenzymes can be readily done in a routine clinical laboratory.

Adolescent↗
PubMed1977

Absorption of inorganic iron- (59Fe2+) in relation to iron stores in pancreatic exocrine insufficiency due to cystic fibrosis.

The absorption of 59Fe from a diagnostic 0.56 mg 59Fe2+ dose was measured by 4pi-geometry whole body counting and related to the amount of stainable diffuse cytoplasmatic non heme storage iron in the bone marrow macrophages of children with cystic fibrosis. When the storage iron was within the normal range (+/2+) children with cystic fibrosis absorbed 10-38% (Xa+/-S.D.=21+/-9.3) of the oral 59Fe2+ dose which is identical with the 59Fe-absorption in normal children with normal iron stores (9-45:23+/-8.7%). Depleted iron stores caused an increase of 59Fe-absorption to 43-95% (Xa+/-S.D.=62+/-19) in children with cystic fibrosis and to 45-100% (Xa+/-S.D.=73+/-18) in control children. The interruption or continuation of pancreatin maintenance therapy and the simultaneous administration of 1-1.5 g pancreatin did not influence 59Fe2+ absorption in cystic fibrosis. There is no evidence for a pancreatic factor required for or inhibiting inorganic and food iron absorption in human beings. Iron absorption is controlled also in cystic fibrosis chiefly by the amounts of available storage iron. It is therefore not justified to apprehend the development of hemosiderosis in children with cystic fibrosis who are not or not sufficiently treated with pancreatin.

Child↗
PubMed1977

Hepatic enzymes, their induction and usefulness in predicting maximal serum bilirubin levels in premature newborn infants.

Sixty-seven babies were utilized to (a) document the serum bilirubin lowering effect and safety of a phenobarbitone and nikethamide combination in neonatal hyperbilirubinaemia of non-hemolytic origin; (b) determine whether birthweight and/or SGOT, SGPT or SGGT activity on day one of life correlated with the maximum serum bilirubin level achieved; and (c) investigate the pattern of hepatic enzyme levels in serum under normal conditions anf following drug induction. Results indicate a significantly lower serum bilirubin level in the treated group of babies. Birthweight and day one SGGT levels, and SGGT/birthweight ratio correlated well with the maximum serum bilirubin reached, the latter ratio being particularly useful in predicting the degree of hyperbilirubinaemia.

Alanine Transaminase↗