Search PubMed⌕ Search

Biomedical subjects

R Köhler

Publications and source records attributed to R Köhler.

At least 73 records · Page 4Linked to original sources
PubMed1987

Effects of acute oral sodium potassium citrate load in healthy males--outlook for treatment of patients with calcium-containing renal stones.

The acute effects of a single (5 g) oral load of sodium potassium citrate (SPC), given together with a liquid test meal, were studied in 6 healthy male volunteers with respect to changes in serum citrate, blood acid base status, urine pH, citrate, calcium and minerals, and oxalate, as well as the calculated relative supersaturation of urine with several stone-forming phases, and the associated crystalluria. It was found that, apart from making the urine more alkaline, SPC induces mild compensated metabolic alkalosis, increases serum and urinary citrate, and reduces fractional urinary calcium excretion, but leaves urinary oxalate and the accompanying crystalluria unchanged. Except for the increase in urinary supersaturation with hydroxyapatite, the supersaturation of other important stone-forming constituents is statistically unchanged. In addition, there are indications that SPC reduces postprandial intestinal calcium absorption without affecting serum parathyroid hormone and 1,25-dihydroxyvitamin D. It is concluded that there is a spectrum of acute effects of oral SPC that may warrant long-term trials on this medication in the metaphylaxis of calcium-containing urinary stones.

Adult↗
PubMed1986

[Determination of N metabolism parameters in an N increase trial in the rat using 15N tracers].

3 groups of 8 Wistar rats each of a live weight of ca. 215 g received graded N supplements. A number of N metabolism parameters were ascertained and discussed. Among other things, the protein synthesis and degradation quotas were ascertained by means of the 15N tracer technique. For the assessment a 3-pool model was used, the content of which was in so far extended as growth and metabolic faecal nitrogen are concretely taken into consideration. A quasi-continuous method of supplementing the tracer was chosen; it was discontinued in approximately the middle of the experiment. Thus the labelling and abatement phases in urine could at the same time be included in the calculation. The protein synthesis quota increases with N intake. It can be concluded from the course of the graph that it gravitates towards a saturation value.

Animals↗
PubMed1986

Generation of human anti-rubella monoclonal antibodies from human hybridomas constructed with antigen-specific Epstein-Barr virus transformed cell lines.

Human monoclonal antibodies (humab) directed against viral antigens were developed by combining immortalization of human primary B lymphocytes by Epstein-Barr virus (EBV) infection with consecutive fusion of selected immortalized lymphoblasts with an established, human lymphoblastoid cell line. Using EBV infection a high rate of immortalized B lymphoblastoid cells was obtained which unfortunately could not be cloned because at least 10 cells per microtiter well had to be seeded to get cells growing. However, fusion of these immortalized lymphoblastoid cells which had been selected for antiviral humab production with an established cell line resulted in hybridomas which could easily be cloned. Among the antiviral humab producing hybridomas thus generated, were three which produced anti-rubella humab. Rubella virus consists of three structural proteins, the core protein C and the two envelope proteins E1 and E2. By the western blot technique we were able to show that two humab reacted with the core protein and the third humab with the envelope protein E1. From the hybridomas grown in stationary cultures, highly purified humab preparations were obtained by subjecting the concentrated culture supernatant to immuno-affinity chromatography.

Animals↗
PubMed1985

[Methodological aspects of the determination of nitrogen metabolism parameters from 15N-tracer experiments on swine based on nitrogen metabolism models. 2. Calculation of N metabolism parameters from the time of urinary excretion of 15N].

After a 45-hour infusion of 15N-lysine and 15N-glycine resp. with pigs of 25 kg live weight, the infusion of the tracer was disrupted and a 3-day reduction phase was made part of the experiment. The N-metabolism parameters such as protein synthesis and decomposition quotas were calculated on the basis of the temporal development of 15N-amounts excreted in urine. The labelling and reduction phases were evaluated simultaneously. By means of including the total N-amount of the animal body the balance calculation becomes more stable. The possible influence of the tracer amino acid in connection with the 3-pool-model is discussed on the basis of the ascertained parameters.

Animals↗
PubMed1984

[Determination of amino acid balance in the gastrointestinal tract of chickens].

11 different feedstuffs (barley, wheat, rye, oat, wheat bran, soybean meal, peanut meal, cottonseed meal, rapeseed meal, horse bean, fish meal) were tested with adult colostomized broiler hens in digestion experiments; the digestibility of the crude protein and the amino acid (AA) balance of the gastro-intestinal tract were ascertained. The results achieved can be summarised as follows: The AA-composition in faecal protein is relatively independent of the AA-composition of the feedstuffs, it is not constant, however. The NPN-quota in faecal crude protein rises with the increasing crude fibre content in the feed. AA-digestibility calculated from the balance of the gastro-intestinal tract is, with the exception of some AA, in particularly the limiting ones, higher than the digestibility of the crude protein. As the AA-balance of the gastro-intestinal tract does not give a realistic picture of the digestibility of the AA, we recommend to ascertain the AA-balance up to the end of the small intestines in order to gain more profound knowledge with the help of such basic investigations with selected feedstuffs.

Amino Acids↗
PubMed1984

[Absorption and use of differently structured protein isolates by rats].

Differently structured isolated proteins with the same amino acid composition were tested with growing albino rats in an N-balance and absorption experiment. The following items were tested: --isolated horse bean protein --hydrolysed isolated horse bean protein with an amino acid supplement to make up for losses due to hydrolysis --horse bean protein-casein (1:1) fibres --isolated horse bean protein with an amino acid supplement to achieve the same amino acid concentrations as in the horse bean protein-casein fibres. The lowest digestibility and utilisation values were ascertained for the hydrolysed protein. Endogenous N-excretion calculated according to the isotope dilution method was higher than for intact proteins, the transport of the chyme in the digestive tract and the true absorption of N in the small intestine had significantly diminished. In comparison with horse bean protein supplemented with amino acids, the horse bean protein-casein fibres showed decreased protein utilisation and increased endogenous N-excretion. Independent of the protein fed and of the time after feeding a relatively constant endogenous N-quota of approximately 70% could be ascertained in the chyme in the small intestine. In contrast to this, the relation between exogenous and endogenous N determined from the contents of the large intestine proved to be dependent on the intermediary utilisation of the protein fed.

Amino Acids↗
PubMed1983

[Methodological studies on determination of the digestibility of crude protein in chickens].

A comparison of various methods for the determination of the digestibility of crude protein in chickens was made. The chemical methods of dividing faeces and urine according to HARTFIEL and EKMAN were tried out, and a new method based on the determination of alpha-NH2-N was developed and tested. Colostomy of hens served as the basis of the comparison for the correctness of the chemical methods. The best approximation to the digestibility quotient of the crude protein according to colostomy was achieved with the alpha-NH2-N-method, which can to a large extent be well automated and can do without N-determination. Faeces-urine-N-separation according to EKMAN also resulted in a good approximation to the values according to colostomy.

Animals↗
PubMed1981

Protectivity of herpes simplex virus antigens: studies in mice on the adjuvant effect of PICLC and on the dependence of protection on T cell competence.

The efficacy of a herpes simplex virus type 1 (HSV-1) envelope antigen (EAG) preparation against HSV infection was studied in T cell competent and T cell deficient mice. Immuno-competent mice were successfully protected against herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) infection when immunized 2 weeks prior to this infection with a heat-inactivated whole virus preparation or a HSV-1 envelope antigen (HSV-1 EAG) preparation. Since HSV-1 EAG was considerably less effective than the whole virus preparation, a poly.riboinosinic-poly.ribocytidylic acid complex with poly-L-lysine and carboxymethylcellulose (PICLC) was used as adjuvant. Immunization with HSV-1 EAG plus PICLC resulted in a pronounced increase of this protection rate as compared with that obtained after immunization solely with HSV-1 EAG. PICLC alone, however, offered no protection when given 2 weeks before challenge. In T cell deficient nu/nu mice no protection was achieved with HSV-1 EAG while their T cell competent, heterozygous littermates were protected. From these results it may be concluded that T cell competence is a prerequisite for establishing a protective immunity against HSV infection after immunization with HSV-1 EAG.

Adjuvants, Immunologic↗
PubMed1981

[Endogenous N-secretion in the small intestine of pigs].

The method of isotope dilution for the determination of endogenous N-secretion was used with three pigs of a live weight of between 15 and 27 kg, which were provided with simple cannulae at the end of the small intestines. The test animals received a single dose of a semi-synthetic ration with 15N-labelled dried curds as sole source of protein. The passage rate to the ileum ascertained with the help of 51Cr2O3 was 70% in 24 hours. During the test period of 24 hours the endogeneous N-amount in the ileum chyme was 1.11 g resp. 56.6 mg/kg live weight. Of that, 60% were allowed to be absorbed in the chyme at the end of the small intestine.

Animals↗
PubMed1981

[Physiological nutrition studies of swine for the evaluation of modified proteins. 3. Relationship between the true and apparent N digestibility and amino acid absorption of the small intestines and the parameters of N metabolism].

Modified proteins were tested in absorption investigations with eight pigs with ileocaecal re-entrant cannulae. The apparent digestibility up to the end of the small intestines showed considerable differences between the feed proteins (77-93%). The same differences could be observed with regard to the apparent absorption of amino acids. Concerning the true N-digestibility resp. the true absorption of the amino acids in the above mentioned section of the intestinal tract there were hardly any differences between the proteins given. The results show that there is a relation between the amount of endogenous N in the chyme at the end of the small intestines and the protein consumed. The amount of endogenous N in the chyme in the small intestines influence N-excretion in urine and thus the intermediary utilisation of feed protein. From the point of view of nutrition physiology it follows that the spun vicia-faba protein/casein (1 : 1) fibres (C) approximate best the value of casein (A). While the treatment of this mixed protein with dyaldehyde starch had a negligible effect on the ascertained parameters only, the treatment of the same protein with aluminium chloride diminished its value more. The isolated vicia-faba (B) was the poorest of the modified proteins tested.

Amino Acids↗
PubMed1981

[Nutritional physiology studies in pigs on the evaluation of modified proteins. 1. Results of the estimation of N-turnover, apparent and true digestibility of proteins in addition to apparent and true absorption of amino acids in the entire digestive tract].

Sulfuric acid-casein (A), spray dried isolated Vicia faba protein (B), Vicia faba protein/casein (1 : 1) protein fibres-untreated (C), treated with dialdehyde starch (D) or aluminum chloride (E) and meal of Vicia faba (F) were studied as sole protein sources in semisynthetic feed mixtures on 13 female pigs (40 to 45 kg body weight). Total utilization of nitrogen (b-value, PNu) and intermediate utilization (BW) were highest in A, followed by C. Protein C was superior to D. Protein E showed a drastic drop in protein quality compared with D because of a high decrease in S-containing amino acids content, however, their efficiency (bc-1-value) was not limited. Despite of a higher apparent digestibility by approximately 17 units in protein B, proteins B and F showed a similar quality. The true absorption of cystine (estimated by the balance of digestive tract) was corresponding to the protein quality of the respective step of treatment of protein C and was used for the correction of the gross content is S-containing amino acids.

Amino Acids↗
PubMed1981

[Nutritional and physiological studies of swine for the evaluation of modified proteins. 2. Determination of endogenous N in the contents of the small intestines using the 15N-tracer method].

The endogenous N-quota in the chyme of the small intestines after providing modified proteins was determined with re-entrant cannulae at the end of the ileum in investigations with pigs (35 to 50 kg live weight) with the isotope dilution method. The N-pool of the test animals was labelled with 15N-glycine and 15N-leucine. The TCA-soluble fraction of the blood plasma served as criterion for the labelling level of the N-pool. The results showed a direct connection between N-intake and endogenous N in the chyme of the small intestines. With regard to N-intake, the dependence of endogenous N in the chyme of the small intestines on feed protein could be observed.

Animals↗
PubMed1981

[Absorption of protein-linked N and synthetic lysine in the small intestine of pigs].

The absorption and absorbility of the protein-linked N was investigated with 3 pigs in the live weight range between 15 and 27 kg, which had been provided with simple cannulae at the end of the ileum and with portal vene catheters. After receiving a semi-synthetic ration with 15N-labelled curds as sole protein source, supplemented with 0,3% 35S-DL-methionine, the course of absorption could be observed both for 15N and 35S with the help of the chyme samples. Considering the endogenous 15N-quota in the chyme in the small intestines, it was possible to acquire data concerning the apparent and true absorption resp. absorbility of the feed-N. It could be ascertained that the supplemented synthetic amino acid is better absorbed than the protein-linked amino acids. So the absorption of 35S amounted to 91,2% of the intake whereas only 84,2% of the labelled N was observed.

Animals↗
PubMed1981

[N-metabolism as modelled by metabolism of 15N-labelled wheat in rat experiment].

Male albino rats of a weight of 90 g received a test ration with 15N-labelled wheat as protein source over a period of 1 to 8 days. The 15N-excess in urine, feces, some organs, the remaining carcass and in the blood was determined in dependence on time. On the basis of two different pool models the N-metabolism values could be calculated. Protein synthesis and disintegration rates calculated by means of the N- and 15N-balances of the pool in the steady state of the pool labelling amounted to 252.9 mg N per day resp 203.0 mg N per day. The calculation based on the time-dependent curve of the daily 15N-excretion in urine resulted in corresponding synthesis and disintegration rates of 197.0 mg N per day and 134.6 mg N per day. Labelling curve and results are discussed.

Animals↗
PubMed1981

[Pathobiochemistry of mineral and trace elements. I. Concentration of zinc in the whole blood and serum of pregnant women and newborn (author's transl)].

The behavior of the zinc level in whole blood and in the serum of 158 gravid patients during the 10th ot the 40th week of pregnancy is studied as well as that of 154 mothers and newborns immediately post partum. The analytic results are related or correlated with the blood groups and rhesus factors of the mothers with the sex of the newborn as well as with the zinc values of mother and child. It is shown that: 1. The disturbance of zinc metabolism during pregnancy in whole blood and serum is just as marked in normal pregnancies as in pathological ones. 2. Lowering of the zinc level is equally great in primiparas as well as in multiparas. 3. The blood group of the gravid patient has no influence on the level of zinc in the maternal whole blood. 4. The rhesus factor as well is of no influence on the zinc level in the whole blood and in the serum of pregnant women. 5. The zinc deficit in the already considerably lowered zinc whole blood values of newborns is significantly greater for male babies than for female babies. 6. The differences in zinc levels in mother and child show no clear-cut meaning.

Adolescent↗
PubMed1981

[Pathobiochemistry of mineral and trace elements. III. Magnesium concentration in whole blood and serum of pregnant women and newborn (author's transl)].

Magnesium is a constitutional or additive component in over 200 enzymes: its significance in physiological or pathophysiological metabolism is therefore considerable. For this reason this element was also included on our program of studies on cation kinetics in pregnant women and in neonates. The results of our analyses of 158 gravid women with normal and toxic pregnancies can be summarized as follows: 1. Compared with the corresponding values for non-pregnant women, the mother's magnesium during a normal pregnancy is reduced up to 9.2% in the serum and, likewise significantly reduced in whole blood up to 7% of normal values. The same conditions apply to the newborn as well. During a pathological pregnancy the magnesium in serum is reduced by 6.3% and in whole blood 6.6% as opposed to non-pregnant women. 2. Serum magnesium decline is equally great for primi- as well as multipara. 3. The blood group of the pregnant women is without influence on the magnesium concentration. 4. The rhesus factor has no influence on the course of the magnesium concentration during pregnancy. 5. The reduction of the magnesium values in whole blood is significantly greater for newborn males than for newborn females. 6. A concrete statement about the extent to which magnesium affects the Apgar values cannot be made on the basis of the data analysed in these studies due to the lack of symmetry between the groups to be compared: groups 5-7 to 8-10. Further comparative studies are required for this. 7. Magnesium changes in mother and child correlate with pregnancy toxicoses and other parameters.

Adult↗