[The dose dependence of 15N-incorporation in organ proteins of newborn rats after pulse labeling with different tracers]

A short-chain 15N-peptide mixture characterized by an average chain length of 2.3 was obtained when 15N-labeled yeast protein has hydrolyzed enzymatically by thermitase from Thermoactinomyces vulgaris. Fifteen newborn Wistar-rats were given a single pulse of [15N]glycine. [15N]H4Cl and [15N]yeast protein-thermitasehydrolysate (YPTH) in a dosage of 50 mg 15N excess kg-1 by gastric tube. In comparison with [15N]glycine the 15N-incorporation rates of brain, muscle and liver were approximately 150% higher after [15N]YPTH-application. Uniform labeling, high 15N-enrichment, almost complete absorption, avoidance of imbalances and the low price make this tracer substance superior to other tracers conventionally used for organ labeling.

15N tracer kinetic studies on the validity of various 15N tracer substances for determining whole-body protein parameters in very small preterm infants

Reliable 15N tracer substances for tracer kinetic determination of whole-body protein parameters in very small preterm infants are still a matter of intensive research, especially after some doubts have been raised about the validity of [15N]glycine, a commonly used 15N tracer. Protein turnover, synthesis, breakdown, and further protein metabolism data were determined by a paired comparison in four preterm infants. Their post-conceptual age was 32.2 +/- 0.8 weeks, and their body weight was 1670 +/- 181 g. Tracer substances applied in this study were a [15N]amino acid mixture (Ia) and [15N]glycine (Ib). In a second group of three infants with a post conceptual age of 15N-labeled 32.0 +/- 1.0 weeks and a body weight of 1,907 +/- 137 g, yeast protein hydrolysate (II) was used as a tracer substance. A three-pool model was employed for the analysis of the data. This model takes into account renal and fecal 15N losses after a single 15N pulse. Protein turnovers were as follows: 11.9 +/- 3.1 g kg-1 d-1 (Ia), 16.2 +/- 2.5 g kg-1 d-1 (Ib), and 10.8 +/- 3.0 g kg-1 d-1 (II). We were able to demonstrate an overestimation of the protein turnover when Ib was used. There was an expected correspondence in the results obtained from Ia and II. The 15N-labeled yeast protein hydrolysate is a relatively cheap tracer that allows reliable determination of whole-body protein parameters in very small preterm infants.

[Protein metabolism and lipid balance in dietary treatment of acute enteritis in infants with a defined standardized oligopeptide diet]

The advantage of a standardized oligopeptide formula (Peptisorb päd) for dietary management of diarrhea was proved in 10 infants aged 1 to 10 months with body weights between 4000 and 8860 g. The nitrogen balance turned to normal already at day 3 to 4 of the treatment due to the rapid increase of food supply. Whole body protein parameters estimated by 15N yeast protein thermitase hydrolyzate as a tracer substance were already normalized at that time. Protein synthesis amounted to 5.0 +/- 1.5 g/kg/day, protein breakdown to 3.7 +/- 1.5 g/kg/day and net protein gain to 1.3 +/- 0.6 g/kg/day, resp. Reutilisation rate of endogenous nitrogen was found to be 83%. This correlates with the relatively high nitrogen supply of the oligopeptide diet in comparison to mother's milk feeding. Approximately 15% of the administered amount of total nitrogen were excreted in the feces in contrast to only 5.8% of the 15N tracer dose, indicating the higher losses of endogenous nitrogen due to enteritis. The absorption of the medium chain triglycerides from the diet was 97.5% at an average and thus extremely high.

[In vitro studies on microbial incorporation of nitrogen from [15N2] urea and [15N]ammonium chloride by human intestinal flora]

6 typical bacteria species of the human intestinal flora (E. coli, Klebsiella pneumoniae, Proteus vulgaris, Streptococcus faecalis, Bacteroides fragilis, Bifidobacterium sp.) were incubated in a liquid medium for 48 h with [15N2]-urea and [15N]-ammonium chloride. The rates of [15N]-incorporation were calculated. They depend reproducible on the species examined, on the kind of the offered NPN-substance and on the amount of NPN-substance in the medium. With [15N2]-urea the minimal rate of incorporation was 3.8% (E coli) and the maximal one 95.6% (Bifidobacterium sp.). With [15N]-ammonium chloride the corresponding figures were 31.0 (Proteus vulg.) and 98.0% (Bifidobacterium sp.). The findings are discussed with regard to a possible enteral detoxification in uremic patients by bacterial utilization and elimination of urea and ammonia.

[15N-tracer kinetic studies on the utilization of urea in protein metabolism of infants]

The virtual importance of the urea circuit is not clear. After a 3 to 21 day application of 100 mg [15N]-urea/l in 15 infants a [15N]-excess value of 0.06 in serum protein could be proven. Taking as a basis a protein content of 11.4% of the body mass and a regular distribution of the [15N] within the body one can calculate a retention of the urea nitrogen in the protein pool of 40.4% of the intake. Taking in account an amount of 11.4% urea nitrogen from the total nitrogen in mother's milk then the amount of urea nitrogen from the net protein accumulation comes to 6.5 (3.1-11.8)%.

Mouse embryo growth in different culture media: selection of a medium for quality control cross-testing of human in vitro fertilization conditions

A total of 2070 two-cell mouse embryos were recovered from 89 superovulated female hybrid mice. Six different culture media were tested. The various media supported mouse embryo development as follows (percentage mean +/- SD, n = 10): Hopp and Pitts medium (H&P) 87 +/- 5 Dulbecco's modified; Eagle's medium supplemented with 10% (volume/volume, v/v) fetal bovine serum (DMEM) 80 +/- 4; Ham's F-10 +/- 15.0% (v/v) human fetal cord serum (hFCS) 79 +/- 3; Whittingham's T-6 medium (WT-6) 60 +/- 4; Ham's F-10 +/- 7.5% (v/v) hFCS 55 +/- 5; Krebs-Ringer low bicarbonate buffer (KRLBB) 42 +/- 6. In H&P, DMEM, WT-6, and Ham's F-10 medium supplemented with hFCS, the pH was maintained within a narrow range of 7.30-7.45 and adequate level of oxygenation was achieved during 72 h in culture. KRLBB had poor buffering capacity and attained ineffective levels of oxygenation during culture. Superior mouse embryo development from two-cells to morulae and hollow blastocysts occurred in H&P, Ham's F-10 + 15% hFCS, and DMEM. Ham's F-10 medium supplemented with hFCS is routinely checked for its ability to support mouse two-cell embryo development to morulae and blastocysts. This is done in conjunction with H&P medium as the control.

15N tracer investigations of the physiological availability of urea nitrogen in mother's milk

The physiological availability of urea in mother's milk was investigated in tracer studies using [15N]2 urea and involving 22 infants. The incorporation of 15N into the body protein was established in 16 subjects by emission spectrophotometrical determination of the 15N excess in the serum protein. Between 2% and 3.6% of the serum protein is synthesized from the urea nitrogen in mother's milk. In further studies on the 15N balance in 6 infants, renal excretion of 15N after oral multiple and single impulse labelling with [15N]2 urea constituted 60% of the dose administered. Three-tenths-2.5% was excreted in the feces. The retention of 15N in the protein pool varied between 16.7 and 61.4%.

Quantitative ultramorphological evaluation of swim-up spermatozoa used in human in vitro fertilization and transcervical intrauterine insemination

Ultramorphological changes that occur on the sperm head during in vitro incubation of human spermatozoa was investigated using transmission electron microscopy (TEM). Motile spermatozoa that swim-up were processed for TEM. Washed but unincubated sperm heads had all of the fine structural characteristics of normal spermatozoa: intact plasma membrane, acrosome, equatorial segment, postacrosomal sheath, subacrosomal space filled with fine granular material, dense nucleus containing conspicuous nuclear vacuoles of differing sizes and numbers, and faintly discernible nuclear membrane. The procedure of washing and centrifugation did not alter the structural integrity of spermatozoa. Any evidence of ultramorphological changes in the incubated spermatozoa appeared to be confined to the surface of the anterior two-thirds of the sperm head. These changes were characterized by detachment of plasma membrane, fusion of plasma and acrosomal membranes, vesiculation of membranes, and exposure of acrosomal contents. There was a significant (p less than 0.001) time-dependent increase in the proportion of spermatozoa with such changes. The anterior border of these denuded sperm heads were bound only by the acrosome that appeared as electron-dense granular material on the outer margin and attached on its inner border to the inner acrosomal membrane. Furthermore, in vitro incubation of washed spermatozoa did not lead to any time-dependent degenerative changes.

Fine structure of spermatozoa retrieved from retrograde ejaculates

The proportion of viable, motile spermatozoa retrieved from retrograde ejaculates has been consistently low. Electron microscopic studies of spermatozoa of retrograde ejaculates collected in Baker's buffer and washed in Ham's F10 medium supplemented with 2% human serum albumin revealed considerable ultrastructural lesions to the sperm head and the midpiece. Swelling and/or loss of plasma membrane was observed in most of the sperm. In others, the membrane continuity was disrupted, and tattered remnants of it remained attached to a grossly abnormal acrosome. The acrosomal cap in the majority of the spermatozoa was swollen and irregular in shape. Some of the spermatozoa lacked the acrosome, and the sperm heads of these were lined by the inner acrosomal membrane. Subcellular derangement in the midpiece of retrograde spermatozoa was characterized by mitochondrial swelling and lysis, indicating definite cytotoxic injury to the spermatozoa. These EM observations are consistent with the findings of high sperm wastage in semen from men with retrograde ejaculation.

15N-tracer-kinetic studies on the nitrogen metabolism of very small preterm infants on a diet of mother's milk

Protein synthesis and breakdown, nitrogen flux and other parameters of nitrogen metabolism were measured in five male preterm infants with a mean gestational age of 30.4 +/- 1.95 complete weeks of gestation and a mean body weight of 1592 +/- 517 g. The infants were fed on mothers' milk; the measurements were made at a post-conceptional age of 31.6 +/- 1.9 weeks of gestation (Ia) and were repeated at 34.4 +/- 1.9 weeks of gestation (Ib). [15N]-glycine (95 atom per cent) was used as a tracer, administered as a single enteral dose of 20 mg/kg. Whole-body protein parameters were calculated from an assumed three-pool model. The results were compared with data from moderately small preterm (II) and full-term (III) infants measured at post-conceptional ages of 36.1 +/- 1.4 and 48.0 +/- 2.8 weeks respectively. Protein synthesis rates tended to decrease with increasing post-conceptional age: 14.3 +/- 4.5 g/kg/d (Ia); 11.8 +/- 2.9 g/kg/d (Ib); 7.9 +/- 2.7 g/kg/d (II); and 7.7 +/- 1.4 g/kg/d (III). Protein breakdown and nitrogen flux showed the same trends. Possible consequences for the appropriate nutrition of very small preterm infants are discussed.

[Determination by 15N tracer kinetics of the half-life of total body protein in premature and mature infants]

Based on 15N-tracer techniques important data of the intermediary protein metabolism can be assessed by compartment analysis. We calculated the half-life of whole body proteins in five preterm and five full term infants in addition to commonly used parameters of the protein metabolism e.g. protein synthesis rate, protein breakdown rate, N-turnover rate, size of metabolic pool, half-life and reutilization of aminoacid-N and the rate of endogenous urinary-N. The infants were aged 27 +/- 4 and 31 +/- 13 days resp. The half-life of whole body proteins were found to be 7.5 +/- 1.8 days in the premature infants and thus significantly shorter than the 16.0 +/- 3.8 days for the full term infants. The differences in the half-life of protein as well as protein synthesis rate and protein breakdown rate reflect the rapid proteinturnover in premature infants in comparison to full term infants.

Urea utilization by the intestinal flora, of infants fed mother's milk and a formula diet, as measured with the 15N-tracer technique

15N-Incorporation by intestinal bacteria was measured under different feeding conditions in 16 infants after a single oral loading of 165 mg [15N2]urea X kg-1 body weight as a tracer. In five subjects on a mother's milk diet, the 15N-excess in the isolated intestinal bacteria was 1.08 (0.17-1.85) atom-%. The mean 15N-excess in the intestinal flora of five formula-fed subjects did not differ significantly from these values [0.63 (0.17-1.05) atom-%]. A trend to a higher incorporation of 15N from labeled urea by the intestinal flora was seen in four infants, who were adapted to an increased nutritional urea supply on a special formula, containing 14 g of milk protein, 80 g lactose, 36 g fat, and 0.35 g urea X L-1. The same observation was made in two infants with chronic renal failure. The incorporation of urea nitrogen by the putrefactive intestinal flora of infants on a formula diet as well as by the bifidobacterial flora of those on mother's milk feeding indicates the utilization of ureas as a source of bacterial protein and nucleic acid synthesis. The adaptive usage of urea for the bacterial metabolism can be considered as a sign of supportive detoxification by the intestinal flora.

15N-tracer investigations into the nitrogen metabolism of preterm infants fed mother's milk and a formula diet

Protein synthesis, protein breakdown, protein-N turnover, and other parameters describing the nitrogen metabolism were measured in five male preterm infants. The weight of the subjects at birth was 2,064 +/- 107 g and the measurements were performed at age 16.0 +/- 4.5 days in the case of the mother's milk diet and 27.4 +/- 6.8 days in the case of the formula diet containing 1.8% protein. The parameters were measured by means of the 15N-tracer technique using [15N]glycine (95 atom %) applied in a single oral dose of 20 mg/kg as a tracer. The three-pool model proposed by Winkler and Faust was used to calculate the whole body protein parameters. No difference in net protein gain, protein synthesis, protein breakdown, or the other protein metabolism parameters were recorded despite the different protein inputs. Renal nitrogen excretion and the rate of endogenous urea N excretion were significantly higher for the formula diet than for the mother's milk diet. The protein synthesis rate of 7.9 g X kg-1 X day-1 was, as has previously been observed, higher than in other age groups. The protein metabolism of the preterm infant older than 33 weeks of gestational age does not benefit from a formula diet based on cow's milk that is richer in protein than mother's milk.

Evaluation of different 15N-tracer substances for calculation of whole body protein parameters in infants

The validity of using different 15N-tracer substances to measure whole body protein parameters, i.e., protein synthesis, protein breakdown, net protein gain, protein turnover, metabolic pool, and reutilization, was assessed by comparing the results obtained with: [15N]glycine, a mixture of 10 15N-labeled amino acids, and a 15N-labeled chicken egg protein in two infants, 9 and 12 weeks old, who were fed human milk. The tracer substances were fed orally as a single dose corresponding to a 15N-excess quantity of 0.2 mmol X kg-1 body weight. 15N Excretion in the urine was measured cumulatively by emission spectrometry, and the data on the protein metabolism were calculated by means of a three-pool model. All three tests yielded consistent net protein gains. The protein synthesis, protein breakdown, protein turnover, and nitrogen reutilization values produced by the [15N]glycine tracer study were higher than those produced by application of the 15N-amino acid mixture and the 15N-labeled egg protein. However, in our opinion, this discrepancy does not justify the replacement of [15N]glycine by expensive 15N-amino acid mixtures as tracer substances.

15N-labelled yeast protein--a valid tracer for calculating whole-body protein parameters in infants: a comparison between [15N]-yeast protein and [15N]-glycine

The validity of [15N]-glycine and 15N-labelled yeast protein as tracers for investigating the parameters of nitrogen metabolism in man was studied by comparisons of each tracer in three infants on different diets. Both tracers were administered with the food as a single oral dose of 0.2 mmol 15N-excess nitrogen per kg body weight. Cumulative 15N-excess excretion in the urine was measured by emission spectrometry and a three-compartment model was used to calculate the pool sizes by computer. In all three comparisons the values calculated for protein synthesis, protein breakdown, protein turnover and reutilization after administration of 15N-labelled yeast protein were slightly lower than those calculated after administration of [15N]-glycine. The particular advantage of applying a highly enriched, completely labelled [15N]-protein instead of [15N]-glycine as a tracer is that the protein, containing some 20 amino acids, doubtless gives a more accurate picture of protein metabolism than the use of a single amino acid labelled with heavy nitrogen. However, the small differences between the whole-body parameters calculated from 15N-labelled yeast protein and [15N]-glycine do not justify the general replacement of [15N]-glycine by 15N-labelled protein.

[Value of the histamine liberation test in the diagnosis of intestinal protein intolerance]

The validity of the histamine releasing test for the diagnosis of cow's milk, soy, and egg protein allergy was checked in 31 infants with clinical features of intestinal protein intolerance. The test was positive in 12 of the infants, but in only 5 resp. 1 among them the prick or the Ouchterlony test were pathological. The remaining 19 infants reacted negatively in all 3 tests and subsequently tolerated oral protein loading. The results indicate the superiority of the histamine releasing test in comparison to the conventional prick- and Ouchterlony test.

D-amino acid utilization in infants measured with the 15N-tracer technique

The utilization rates of D-[15N] valine, D-[15N] leucine, D-[15N] phenylalanine and D-[15N] alanine were investigated in seven infants being fed parenterally. Retention of the (15)N in the protein pool varied from one amino acid to another and ranged from 23.2% for D-[15N] valine to 48.6% for D-[15N] alanine. In the case of valine it was shown that cumulative renal excretion amounted to 70% of the applied (15)N-dose, 44% being overflow of unchanged D-[15N] valine, 16.6% appearing as [15N] urea and 1.2% as [15N] ammonium. This indicates that doubling the concentrations of D-amino acid racemates compared with their L-isomer counterparts in parenteral feeding solutions must inevitably lead to imbalances. The use of D-amino acids for the purposes of parenteral nutrition remains however ineffective due to their poor and variable utilization compared to L-amino acids.

[Urea as a substrate for the intestinal flora of the infant (author's transl)]

The significance of the relatively high urea content of mothers milk for infant nutrition was investigated using 15N urea as a tracer by oral loading tests and an in-vitro culturing of bifidobacteria. The urea level of 6 mother's milk specimens was found to be 295 +/- 49 mg/l. There was a distinct incorporation of 15N into the intestinal bacterial fraction following 15N urea loadings in 3 infants, receiving mother's milk and 2 cows milk formulas which contained 1.8 and 2.1% of protein. The incorporation rate did not differ between the single types of feeding. In contrast to these findings the 15N incorporation into the bacterial flora of an infant suffering from kidney insufficiency was about 30 times higher than in healthy infants. Bifidobacteria infants derived from the feces of a breastfed infant utilised 15N from 15N urea added to the culture medium in concentrations of 20 mg per 100 ml. After incubating the culture for 2 days at 37 degrees C the 15N-excess of nitrogen fraction of the bifidobacteria amounted to 0.47 atom-%. Urea therefore can directly serve as a substrate for bifidobacteria on mother's milk feeding.

[Varying utilization of glucose and sorbitol in drug-induced hypercortical metabolism]

Utilisation of glucose and sorbitol in medically induced hypercorticalic states was investigated by means of the steroid-glucose-tolerance-test (SGTT) in 9 children, aged 6-16 years suffering from obesity and prediabetes. Prednisolone (1 mg/kg up to 20 mg) was applied 9 and 3 h prior to the loading tests. Blood samples were taken 0, 2, 5, 30, 60, 90, 120, 150 and 180 min after the onset of the loading tests. During the intravenous infusion of glucose (initial 0,33 g/kg followed by 12 mg/kg/min through 2 h) the mean blood glucose values increased from 103 +/- 15,5 to 388 +/- 96,6 mg/100 ml. Decrease of glycemia began delayed after 90 min, and did not approach the 180 min normal values in 3 of 9 patients. In analogous sorbitol-loading tests performed 2 to 6 days later blood glucose rose from 93 +/- 16,6 mg/100 ml to 129 +/- 28,7 mg/100 ml only. There was a significantly higher blood glucose level on SGTT as compared to steroid-sorbitol loading through the whole test period. Renal losses of glucose after SGTT as well as sorbitol losses after steroid-sorbitol loading amounted to approximately 14% of the doses supplied. The resulting data point to the advantages of combined glucose and non-glucose carbohydrate application for parenteral nutrition in medically induced and postoperative hypercorticalic states of metabolism.

The effect of oral contraceptives on reproductive function during semichronic exposure to ethanol by the female rat

1. Female rats were placed on water, 5% ethanol (ET), or 20% ET drinking solutions for 8 weeks. The last 2 weeks, the rats received orally either ethinyl estradiol (EE), norethindrone acetete (NED), or a combination of both. 2. Luteinizing hormone decreased due to ET drinking and was undetectable subsequent to the steroidal treatment. 3. Prolactin increased after steroid treatment and alcohol drinking in the controls. 4. Ethanol (5%) plus EE increased prolactin as did the steroidal combination, whereas ET (20%) likewise increased prolactin in conjunction with NED over water controls. 5. Hepatic alcohol dehydrogenase was inhibited due to EE when compared to water-controls in the 5% ET drinking animal, whereas aldehyde dehydrogenase was induced in combination with NED in both the 5% and 20% ET drinking rats.

[Amino acid substitution with Infesol in chronically hemodialyzed children]

The L-amino acid solution Infesol and the DL-amino solution Alvesin-new were one after the other investigated for their ability as a substitution of losses of amino acids conditioned by dialysis in 4 children with chronic renal insufficiency. The permanent intravenous drip infusion of 200 ml Infesol during 2 hours after the end of the haemodialysis led to a slight increase of the serum amino acids, which had normalized in a control 12 hours after the beginning of the infusion. The mean value of urea in the serum had increased after 2 hours by 17.60, after 12 hours by 3.65 mg compared with the initial value after the dialysis. The analogous infusion of Alvesin-new led to an on an average higher increase of the serum amino acids in the same patients. In the control after 12 hours the methionine-isoleucine, phenylalanine and arginine values in the serum were still significantly increased compared with the Infesol series. At the same time the mean value of serum urea increased by 80.95 mg/100 ml after two hours. After 12 hours it had increased by 105.5 mg/100 ml compared with the initial value. Thus, the solution of L-amino acid infesol is suitable for the compensation of losses of amino acids conditioned by dialysis. However, its application is reserved for larger dietetically not compensable condition of the lack of amino acids and protein.

[Cerebrospinal fluid protein levels and blood-cerebrospinal fluid ratio of glucose and electrolytes in infants and children]

The cell and protein content of the cerebrospinal fluid (CSF) and the CSF/serum ratio of glucose, sodium, potassium, calcium, phosphate and chloride were investigated in 71 children without cerebromeningeal illness and aged 0-4 weeks, 5-8 weeks, 3-6 months, 7-12 months, 1-6 years and 7-14 years. The protein content of the CSF was 730 +/- 146 (530-950) mg/l for the age group 0-4 weeks, and 530 +/- 221 (270-950) mg/l for the age group 5-8 weeks. It was significantly higher than for all subsequent age groups. The CSF glucose accounted for 68-82% of the blood glucose. The serum/CSF ratio for sodium ranged from 101 to 104%, for potassium from 55 to 64%, for calcium from 48 to 70%, for phosphate from 24-29%, and for chloride from 106 to 114%. The decrease in serum and CSF potassium and phosphate concentrations from infancy to school age was significant. The greatest difference was evident in the serum/CSF calcium ratio which was significantly higher in the age groups up to 8 weeks than in the subsequent age groups. The electrolyte concentration of CSF with elevated protein and cell values did not differ significantly from CSF of children without cerebromeningeal disorders.

[Kinetic tracer studies on protein synthesis during infancy using chemically defined diets containing 15N-lysine as a tracer (author's transl)]

A four-month-old infant with exocrine pancreas insufficiency was fed exclusively on a chemically defined diet. The amino acid formulation of this diet (a supplemented casein hydrolyzate) corresponds to that of breast milk. The 15N labeled lysine tracer (97.4 atom-%) was included in the diet without changing its chemical score. A trace dose of 2.22 mg/kg body weight was applied for 5 days after the infant had been maintained on a chemically defined diet for 11 weeks. Urine was collected over a period of 170 h. The compartment theory was used to calculate the following metabolic data. Cumulative renal 15N excretion showed that nitrogen retention was 90.8%. Protein synthesis amounted to 10.34 g kg-1 d-1 compared with a protein breakdown rate of 8.97 kg-1 d-1. Net protein gain in this infant was about 5.5 g d-1 corresponding to a rate of 1.38 kg-1 d-1 or 13.3% of the synthesis rate. The metabolic pool amounted to 4.96 g N kg-1 d-1. 75.99 mg N kg-1 h-1 was metabolized, mainly to protein, and only about 10% was excreted with the urine.

Preliminary testing of the contraceptive collagen sponge

The results of 3 years of developing the collagen sponge as an intravaginal contraceptive are presented. Postcoital tests were used to evaluate the efficacy of the sponge as a mechanical barrier. Results with the collagen sponge alone were compared to those of the sponge with spermicidal cream or spermicidal solution (acid buffer and zinc) and of spermicidal cream alone. The presence of any motile spermatozoa in the cervical mucus was considered a failure of the barrier method. The collagen sponge alone or with acid and zinc and spermicidal cream alone had failure rates of 22, 20, and 14%, respectively, whereas the collagen sponge with spermicidal cream had a 6% failure rate. The authors conclude that the combination of a mechanical and a chemical barrier is a more effective contraceptive method than a mechanical barrier or chemical agent alone.

[Differential therapy of parenteral and special feeding in intensive medicine]

After having overcome the acute danger to life by a directed infusion therapy as well as by medicamentous, physical and operative measures question of the long-term nutrition frequently come fully into the foreground in intensive medicine. For this purpose as modern methods are at our disposal parenteral nutrition with mixtures of amino acids, carbohydrates and fat emulsions, the feeding by a stomach tube with easily decomposable mixtures of proteins, carbohydrates and fat and the feeding by a stomach tube with chemically defined diets. When the adequate form of nutrition is chosen, depends on the indications and contraindications for the use of these nutrient solutions and on the adequate stage of the present basic disease. The optimum nutrition of the intensive therapy patients is an essential prerequisite for the prevention and overcoming of the severe secondary diseases, which frequently develop after emergency situation and destroy the success of the initial therapy.

Studies on ethanol and oral contraceptives: feasibility of a hepatic-gonadal link

Adult male and female rats were subjected to gonadectomy by means of surgical removal of the gonads. In the male, castration resulted in a significant decrease in both body and liver weights compared to intact controls, which persisted for at least 3 weeks. Conversely, ovariectomy was associated with a significant enhancement in both growth rate and liver weight from intact controls. Castration of male rats resulted in induction of hepatic L-ADH (cytosolic alcohol dehydrogenase) and L-ALDH (cytosolic aldehyde dehydrogenase) as contrasted with inhibition of mitochondrial ALDH which was evident in the enzyme with the apparent high Km. Kinetic studies indicate that there was an increase in apparent Km of L-ADH, and hence reduced affinity to hepatic metabolism of ethanol as a consequence of castration in the male rat. This is compared with few changes occurring in the apparent Km value of L-ALDH. Ovariectomy did not alter endogenous L-ADH or L-ALDH. Short-term administration of a synthetic estrogenic steroid ethinyl estradiol, inhibited liver mitochondrial ALDH in the intact female rat but not in the ovariectomized female. Short-term administration of the same dose of an androgen, testosterone, did not alter specific activities of the liver enzymes measured in the intact or in the castrated male rat. Administration of both components of OCs (oral contraceptives) combined or the estrogen alone in behavioral experiments profoundly reduced ethanol drinking by voluntary intake of diluted ethanol solution by the intact female rat. These results suggest a hepatic-gonadal link may exist and that a toxic interaction between the OCs and alcohol drinking is definitely possible.

Twelve years experience in establishing larger colonies of small laboratory animals under SPF conditions by means of germfree technology

The special procedures and techniques to develop poly-associated gnotobiotic animals in order to start large SPF colonies of small laboratory animals are discussed.

Lactose and protein absorption from breast milk and cow's milk preparations and its influence on the intestinal flora. Investigations on two infants with an artificial anus

Lactose and protein absorption from breast milk and a cow's milk preparation enriched up to 7% of lactose were studied in two infants with an artificial anus applied in the ascending colon region. The concentrations of protein, lactose, glucose and galactose were measured in the fistula stools. In addition, the stools were analysed microbiologically. There were relatively high concentrations of lactose and its decomposition products and low concentrations of protein and aminonitrogen in the fistula stools when breast milk was fed. When the cow's milk formula was applied, only traces of lactose but high amounts of protein were measured. The microbiological findings are in agreement with the hypothesis that the bacterial flora of the large intestine is influenced by the lactose and protein concentrations in the intestinal content which reach the large intestine.