[Chloroquine and fansidar resistance of Plasmodium falciparum now also in Ghana]

The authors report on the occurrence of chloroquine- and fansidar-resistant Plasmodium falciparum strains. From their results the authors draw the necessary conclusions for recommendations with regard to the prevention of life-endangering tropical malignant malaria.

The structure of manumycin. II. Derivatives

Derivatives of manumycin (1) were obtained by acetylation and reduction, respectively, and characterized by their spectroscopic data. Structure-activity relationships of the antibiotic were discussed.

The structure of manumycin. I. Characterization, structure elucidation and biological activity

Manumycin (1), produced by Streptomyces parvulus (strain Tü 64), was isolated from the mycelium by extraction with acetone and could easily be purified chromatographically. Chemical degradation of 1 (C31H38N2O7) gave 2-acetamino-3-hydroxycyclopent-2-enone (2) by acetolysis, 2,4,6-trimethyl-2,4-decadienoic acid (3) by alkaline hydrolysis, and 2-(2,4,6-trimethyl-2,4-decadienoylamino)-5,6-epoxy-1,4-benzoquinon e (5) by chromic acid oxidation. In connection with a detailed spectroscopic analysis, the structure of 1 could be elucidated and the (E)-configuration of the double bonds in the triene and diene chain was established. Manumycin exhibits biological activity against Gram-positive bacteria and fungi and furthermore, an inhibition of the developmental processes of some insects.

[Diagnosis of drug-resistant strains of Plasmodium falciparum]

Expanding drug-resistance of P. falciparum strains is one of the main problems of the control and treatment of malignant tropical malaria. The World Health Organisation recommends the in vivo test as well as macro and micro in vitro tests for the epidemiological and clinical diagnosis. The authors describe the methodology of these tests, which helped them to identify the first chloroquine-resistant P. falciparum strains from Moçambique and Angola as well as one fansidar-resistant strain from Angola.

Absolute bioavailability of testosterone after oral administration of testosterone-undecanoate and testosterone

The plasma levels of testosterone (T) were measured after oral administration of 25 mg T and 40 mg testosterone-undecanoate (TU) in a group of young women by a specific radioimmunoassay. Plasma levels were compared to those after intravenous administration of 1.5 micrograms testosterone/kg to another group of young women for determination of absolute bioavailability. Due to the high metabolic clearance rate of 24.5 ml/min/kg absolute systemic availability of free testosterone was calculated to 3.56 +/- 2.45%. Oral administration of testosterone undecanoate leads only to an absolute testosterone bioavailability of 6.83 +/- 3.32%.

[Modification of vasoconstriction in ischemically stressed and extracorporeally perfused dog kidneys by alpha adrenergic blockade with phenoxybenzamine]

Renal vasoconstriction was induced in mongrel dogs by clamping the pedicle for 30 min. After reestablishing the renal blood flow for 10 min, the kidneys were removed and flushed for 15 min with cooled Euro-Collins solution. As to estimate the spasmolytic effect of alpha adrenergic blockade with phenoxybenzamine (2 mg/kg) the left or right kidney was first flushed without post-ischemic blockade (control), whereas before nephrectomy of the remaining kidney the dogs received phenoxybenzamine. This was injected intravenously either immediately after the ischemia period maintaining the physiologic blood pressure by volume substitution (group 1) or without volumetric stabilization of the pressure (group 2) or 30 s before the harvesting procedure (group 3). The results showed that pretreatment with phenoxybenzamine in all groups caused a significant reduction of the renal vascular resistance and an improved microcirculation of the Collins solution during the isolated kidney perfusion as compared to the untreated kidneys. The vasodilatatoric effect markedly depends on the blood pressure during the reflow interval and on the time of bolus application before nephrectomy.

[Humoral immune response, concentration of selected serum proteins and transplant histology following allogeneic kidney transplantation in the rat]

After transplantation of (BD IX X Sprague-Dawley) F 1 kidneys into untreated BD IX rats (n = 29) the first signs of rejection occured on day 4. Mononuclear cells infiltrated the peritubular interstitium and/or the perivascular areas. The rise of blood urea on day 8 was histologically accompanied by injured tubules and spotted or confluent subcapsular necroses which showed extensive calcifications by day 10. At the same time donorspecific lymphocytotoxic antibodies were detected in peripheral blood. The graft survival in this strain combination ranged from 11 to 16 days. The serum levels of IgG, albumin and transferrin were reduced by 16%, 25% and 21% resp. in the 1st posttransplant week. In contrast, the serum level of alpha 2-macroglobulin rose on the 2nd postoperative day to an average of 800% above the mean. In connection with rejections only the alpha 2-macroglobulin showed changes of the serum level.

Programmable auditory stimulus generator and electro-acoustic transducers--measurements of sound pressure in an artificial ear and human ear canal

The measurement of sound pressure wave forms of different headphones resulted in considerable differences in an artificial ear and in the external auditory canal in man. This concerns, in particular, the pattern of stimuli used to elicit the auditory nerve and brain-stem auditory evoked potentials. By varying the electrical input to the headphones by means of a programmable stimulus generator, it can be shown that the sound pressure wave form can be influenced considerably.

Evidence for valine intolerance in patients with cirrhosis

Valine (62.5 mg per kg), leucine (70 mg per kg) and equal amounts of the calcium salts of the corresponding keto acids, i.e., alpha-ketoisovaleric acid (KIVA) and alpha-ketoisocaproic acid (KICA) were orally administered to patients with cirrhosis and to control subjects. Valine or leucine ingestion increased serum valine and leucine levels and the corresponding keto acids, KIVA and KICA, in cirrhotics and controls. KIVA or KICA ingestion increased serum KIVA and KICA concentrations within a few minutes associated with a rise in valine and leucine. In cirrhotics, administration of valine or KIVA resulted in significantly higher serum valine or KIVA concentrations than in control subjects. The clearance of valine and KIVA from blood was also delayed in cirrhotic patients. No such differences were observed after leucine or KICA ingestion. It is suggested that cirrhotics have a diminished tolerance for valine. Since the tolerance for KIVA, but not KICA, is also impaired, it appears that cirrhotics have a derangement in one or more metabolic steps distal to the branched-chain keto acid dehydrogenase.

Serum branched-chain amino and keto acid response to a protein-rich meal in man

In 8 healthy volunteers blood levels of branched-chain amino (BCAA) and keto acids (BCKA) were determined in response to a protein-rich meal. Serum concentrations of leucine, isoleucine, valine, alpha-ketoisocaproic acid and alpha-keto-beta-methyl-n-valeric acid increased within 30 min and continued to rise throughout the observation. Only the keto analog of valine remained unaffected. As the BCAA increased significantly more percentagewise than their keto analogs, the ratios between amino and keto acids became augmented. It is suggested that (1) augmentation of keto acids may reflect transamination of amino acids rather than intestinal uptake; (2) the overall capacity of the organism for decarboxylation of ketovaline is greater than for the other keto acids, and (3) augmentation of the ratio between BCAA and BCKA may favor the storage of amino acids from the protein load into the body's protein stores.

Microvascular surgery in experimental and clinical kidney transplantation

An improved microsurgical technique for orthotopic rat kidney transplantation is described in detail. (1) End-to-end anastomosis of renal arteries with 7-8 interrupted 10-0 sutures. (2) End-to-end anastomosis of renal veins with 2 continuous semicircular 10-0 sutures. (3) Non-splinted end-to-end ureteric anastomosis with 4 interrupted full-thickness 11-0 sutures. (4) Simultaneous bilateral nephrectomy. Seventy transplantations were analysed. No failure due to complications of the vascular anastomoses occurred. The ureteric anastomoses were complicated by stenosis in only 5 animals (7%). The operation times for vascular anastomoses were 20 (15-24) minutes and for complete transplantation 50 (45-60) minutes. This technique seems to be less time consuming than other methods. Our method has produced a success rate of 93% with well standardized and reproducible organ quality. Preliminary clinical experiences with extracorporeal microvascular reconstruction in 4 cases of injured small polar kidney allograft arteries support the continued application in appropriate situations to increase the number of suitable donor kidneys.

Stability of enzymes in urine at 37 degrees C

The activity of alanine aminopeptidase, alkaline phosphatase, gamma-glutamyltransferase, lactate dehydrogenase and beta-N-acetyl-D-glucosaminidase in urine at 37 degrees C was investigated by a model simulating in vivo conditions. The stability of these urinary enzymes is influenced particularly by pH. At low pH values in urine (about pH 5.0) the four first-mentioned enzymes rapidly lose a considerable part of their activity, whereas beta-N-acetyl-D-glucosaminidase is inactivated at higher pH values in urine (about at pH 8.0). This inactivation effect is also time-dependent and can be modified by urinary substances such as creatinine, urea and electrolytes. To avoid misinterpretation of enzyme activity determinations in urine, the simultaneous measurement of urinary pH should be performed.

[Passive enhancement of allogeneic rat kidney transplants with antibodies against nylon-adhering splenic lymphocytes]

Male BD IX rats were intraperitoneally immunized with 6.35 X 10(6) nylon adherent spleen lymphocytes from male Sprague-Dawley rats (SD). The inbred strains used are different from each other at their major histocompatibility complex. Sensitized animals were exsanguinated 2, 4, 8 and 12 days after the primary injection. After the secondary injection on day 14 the animals were exsanguinated on day 21. The BD IX recipients of (BD IX X SD) F1 renal allograft were intravenously injected with 1 ml of the antisera immediately after completion of the transplant. Significant prolongation of survival time was already obtained with the 8-day-serum pool. The absorption of antiserum with packed SD red blood cells did not affect its enhancing activity. In vitro testing of antisera by 51Cr-release assay showed the highest titer of complement depending cytotoxicity 8 days after immunization. Whilst the cytotoxic activity against nonadherent spleen cells was completely lost after twice absorption with SD erythrocytes, the cytotoxic activity against adherent spleen cells was only slightly reduced. Thus it is likely that enhancing activity of alloantiserum is attributed to anti-Ia or anti-B-cell antibodies. These antibodies were detectable 4 to 8 days after immunization with low dose nylon adherent spleen cells.

Influence of insulin on blood levels of branched chain keto and amino acids in man

Branched chain keto acids, their corresponding amino acids, glucose, glucagon, growth hormone, C-peptide and gastric inhibitory polypeptide were determined in 8 healthy subjects after an intravenous bolus injection of 0.1 U/kg insulin. Branched chain keto acids declined within 60 min, the corresponding amino acids within 20 min or later. Amino acids tended to return towards normal earlier than their keto acids. Blood glucose levels were normal 2 hr after insulin injection while keto and amino acids remained diminished for more than 3 hr. In 8 healthy controls, given physiological saline instead of insulin, the branched chain keto acids did not decline throughout the test. It is suggested that insulin diminishes blood levels of branched chain keto acids, that the intraorgan flux of branched chain keto acids is different from the flux of branched chain amino acids and that branched chain keto acids may serve to correct for hypoglycemia.

Urinary enzyme excretion by renal-transplant recipients in relation to interval after transplantation

We determined the urinary excretion of the enzymes aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), and N-acetyl-beta-glucosaminidase (EC 3.2.1.30) in two groups of renal-transplant recipients at different times after transplantation (1.8 months and 52 months, respectively). Both groups of patients showed a higher rate of enzyme excretion than did a reference group of healthy persons. More aminopeptidase and N-acetyl-beta-glucosaminidase were excreted during the early period after transplantation than later. The time-dependence of urinary enzyme excretion was confirmed in six renal-transplant recipients studied during the course of 15 months after transplantation. There was a general correlation between the extent of urinary enzyme excretion and both the time after transplantation and the daily dose of prednisolone. Therefore, it is necessary to take into account this influence on the extent of urinary enzyme in renal-transplant recipients if urinary enzyme excretion is used as an indicator of renal disorder and especially as an early predictor of transplant rejection.

Urinary enzyme excretion by renal-transplant recipients in relation to interval after transplantation

We determined the urinary excretion of the enzymes aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), and N-acetyl-beta-glucosaminidase (EC 3.2.1.30) in two groups of renal-transplant recipients at different times after transplantation (1.8 months and 52 months, respectively). Both groups of patients showed a higher rate of enzyme excretion than did a reference group of healthy persons. More aminopeptidase and N-acetyl-beta-glucosaminidase were excreted during the early period after transplantation than later. The time-dependence of urinary enzyme excretion was confirmed in six renal-transplant recipients studied during the course of 15 months after transplantation. There was a general correlation between the extent of urinary enzyme excretion and both the time after transplantation and the daily dose of prednisolone. Therefore, it is necessary to take into account this influence on the extent of urinary enzyme in renal-transplant recipients if urinary enzyme excretion is used as an indicator of renal disorder and especially as an early predictor of transplant rejection.