The biosynthesis of the antibiotic pyrrolnitrin by Pseudomonas aureofaciens

Feeding experiments with tryptophan samples labeled specifically with radioactive and stable isotopes have shown that Pseudomonas aureofaciens converts this amino acid into pyrrolnitrin in such a way that the indole nitrogen gives rise to the nitro group, the amino group becomes the pyrrole nitrogen, C-3 of the precursor side chain becomes C-3 of the antibiotic, and H-2 of the indole ring and H-alpha of the side chain give rise to H-5 and H-2 of pyrrolnitrin, respectively. Only the L-isomer of tryptophan is incorporated with retention of the alpha-hydrogen and the amino nitrogen. From the D-isomer the labels from these two positions are lost. The obvious conclusion that L-tryptophan is the more immediate precursor is, however, contradicted by the better incorporation of D- than L-tryptophan into the antibiotic. Several potential pathway intermediates were evaluated for incorporation and 4-(0-aminophenyl)-pyrrole was found to be a good precursor. The results area discussed in terms of a plausible pathway for pyrrolnitrin biosynthesis.

[The cardiovascular effect of diisopropylaminhydrochloride (Disotat) in non-pregnant hypertensive women]

With the help of the quantitative sphygmometry and the unbloody graphic registration of the arterial pressure the hemodynamic effect of diisopropylamine hydrochloride (disotat) was investigated in 10 non-pregnant hypertensive patients. After a rapid intravenous application of 100 mg diisopropylamine hydrochloride (DIIPA) within 10 minutes after injection a statistically significant decrease of the systolic pressure by 15%, of the diastolic pressure by 9% and of the arterial medium pressure by 15% developed. Thus the blood pressure amplitude was restricted by 25%. Connected with the decrease of the pressure was a significant decrease of the stroke volume by 22% and of the cardiac output by 19%. The total peripheral resistance increased statistically uncharacteristically by 13% in comparison to the initial value. The courses of the curves show that in all parameters during the 45-minute observation duration the initial values are striven for, however, without reaching them in every case. Thus the decrease of pressure induced by bolus injection of DIIPA independent on the existence of pregnancy is always accompanied by a decrease of the output volumes of the heart and the increase of the total peripheral resistance.

[Clinical and experimental results on the significance of kidney damage for long-term prognosis after kidney transplantation]

In the clinical study the influence of the differently long times of warm ischaemia and of the duration of the acute renal insufficiency post transplantationem on the late prognosis of the grafts and the survival of the patients as well as on the incidence of complications in 93 patients who first underwent a transplantation of the CD-kidney and who more than two months after the transplantation lived with a working kidney was examined. A direct relation between the duration up to the beginning of the function of the kidney and the long-term prognosis of the patients was proved. In the group with immediate beginning of the function of the kidney at an average WIZ of 13 minutes the creatinine clearance was significantly higher and the incidence of severe infections in the late phase was lower than in the groups with longer WIZ and very retarded beginning of the renal function. Haemodynamic investigations on the autograft model of the dog after 30 minutes WIZ resulted in a pathologically increased renal vascular resistance and in a restricted filtration function up to 4 weeks post transplantationem.

[Viability testing during preservation of dog kidneys with an albumin-containing perfusion solution]

In models experiments on kidneys of dogs the prognostic significance of hydrodynamic, metabolic and enzymatic parameters in the machine preservation with an oxygenated-albumin-containing solution was tested. While the hydrodynamic and metabolic measuring values did not give a clear reference to different ischaemic restrictions of the functional capacity after autotransplantation, the activities of lactate dehydrogenase and N-acetyl-beta-D-glucosamidase in the perfusate proved to be suitable criteria of vitality. In this case the determination of lactate dehydrogenase is to be preferred on account of the smaller methodical expenditure.

[Metabolic products of microorganisms. 175. Tetracenomycin C (author's transl)]

Streptomyces glaucescens, strain Tü 49 = ETH 22794, produces hydroxystreptomycin as well as the tetracenomycins, a mixture of several lipophilic antibiotics. The main component and the most active one is tetracenomycin C. Tetracenomycin C has a molecular formula C23H20O11 and is chemically related to tetracyclines and anthracyclinones. The pale yellow antibiotic is active against some gram-positive bacteria, especially against streptomycetes. Gram-negative bacteria and fungi are not inhibited. In considering the differences of biological activity and the functional groups of the molecule, tetracenomycin C is not a member of the tetracycline or anthracyclinone group of antibiotics.

[The effect of proteinase inhibitor aprotinin on RNA-synthesis rate after partial hepatectomy in rats (author's transl)]

The effect of Aprotinin has been investigated on RNA-synthesis rate--measured by the incorporation of 3H-uridine--after partial hepatectomy in rats. In the control group two maxima of the incorporation of 3H-uridine into the regenerating liver were obtained after hepatectomy. On the other hand no increase of the 3H-uridine incorporation was detectable after Aprotinin pretreatment. The results indicate that Aprotinin inhibits the early events of liver regeneration by inhibition of proteinase enzymes.

[Haemiton compositum in the ambulatory therapy of hypertension]

Comparative treatments of 14 patients suffering from arterial hypertension of the stages II to IV with haemiton and haemiton compositum (haemiton, triamteren and hydrochlorothiazide) lasting three weeks each showed that under influence of haemiton compositum the systolic blood pressure was lower in which case particularly reactions of orthostasis were practically absent. Measured on the approach of the quotient duration of pulse period to duration of basic vibration T/Tfem to the integrity and to the temporary peak value after Jungmann and coworkers which is parallel to the contractility the regulatorily better behaviour of the circulation under haemiton compositum is significantly expressed. In this case no changes of glucose content in the blood and of the potassium content in the serum appear. The sodium content of the serum slightly decreased in the medication of the combination preparation containing the saluretic. Under haemiton compositum the side effects are more insignificant.

Changes in serum and urine lysozyme activity after kidney transplantation: influence of graft function and therapy with azathioprine

We investigated changes in lysozyme activity in serum and urine of kidney-transplant patients, and found that the production and catabolism of lysozyme in such patients differs markedly from that in normal subjects. Resumption of graft function decreases the high serum lysozyme activity by increasing the rate of catabolism in the transplant; at the same time, however, the production is inhibited by therapy with azathioprine. Changes in serum lysozyme activity correlate well with leukocyte count; thus its determination might be useful in monitoring immunosuppression. The urinary excretion of the enzyme, although not specific to rejection, is a good index of the degree of tubular damage.