[Can microorganisms survive upon high-temperature heating during the interplanetary transfer by meteorites?].

One of the most important aspects of the problem of life transfer in the cosmic space is the resistance of microorganisms to high-temperature heating during the launch and entry into the atmosphere. The high-temperature limits of the survival of microorganisms were studied under conditions modeling the laungh from the Mars and the landing on the Earth. Two strain of E. coli K12 exposed to short heating pulse were studied in order to tind out if they could resist high temperature while being in the desiccated state. The procedure was performed in vacuum. It was found that a fraction of bacteria survive heating pulses up to 250 degrees C in vacuum, while similar heating at normal atmospheric pressure leads to the total sterilization of samples.

[Study of the use of noninvasive ventilation of the lungs in acute respiratory insufficiency due exacerbation of chronic obstructive pulmonary disease]. / Issledovanie primeneniia neinvazivnoi ventiliatsii legkikh pri ostroi dykhatel'noi nedostatochnosti na fone obostreniia khronicheskogo obstruktivnogo zabolevaniia legkikh.

Noninvasive positive pressure ventilation (NPPV) is a life-saving procedure in acute respiratory failure (ARF), but its technique is not yet in routine use in many respiratory centers. We carried out a prospective randomized study comparing the combination of NPPV with conventional therapy (oxygen, bronchodilators, steroids, and theophylline) with conventional therapy alone in patients with acute respiratory failure caused by exacerbation of chronic obstructive pulmonary disease (COPD). A total of 58 patients were recruited from a large group of patients admitted to our hospital between September 1995 and March 1997. Twenty-nine patients were randomly assigned to the NPPV group and 29 to the conventional (non-NPPV) group. The patients were matched for demographic and physiological norm values (mean age 63.4 +/- 5.5 vs. 66.2 +/- 7.1 years, mean FEV1 0.68 +/- 0.15 vs. 0.74 +/- 0.16 L, PaO2 51.4 +/- 6.8 vs. 52.3 +/- 6.5 mm Hg, PaCO2 63.4 +/- 10.9 vs. 64.9 +/- 9.7 mm Hg, and pH 7.28 +/- 0.07 vs. 7.26 +/- 0.06). The outcome end points were needed for endotracheal intubation, length of hospital stay, and incidence of complications. NPPV was administered using BiPAP ventilatory device (Respironics, Inc.) by spontaneous and spontaneous/timed modes via nasal and facial masks. The mean time of NPPV was 29 +/- 25 h. Three patients refused from NPPV because of intolerance of mask or ventilation procedure. Two of them were eventually intubated and one of them died. In patients administered NPPV, we observed a significant rise of pH and fall of PaCO2 after 1 h of ventilation, in contrast to the non-NPPV group (7.34 +/ 0.09 vs. 7.21 +/- 0.08, p < 0.05; 53.2 +/- 10.7 vs. 71.4 +/- 10.2 mm Hg, p < 0.01, respectively). The need in intubation was lower in the NPPV group as compared to the reference group (12 vs. 28%, p = 0.18), mortality rate was higher in the non-NPPV group (31 vs. 8%, p = 0.03), and hospital stay was shorter in NPPV patients (26 +/- 7 vs. 34 +/- 10 days). The incidence of complications was lower in the NPPV group, they were less significant, and did not involve discontinuation of ventilation. Hence, NPPV is a first-line therapy in patients with ARF caused by COPD exacerbation, due to obvious advantages over conventional methods of treatment.

[Aminobenzoic acid derivatives as specific inhibitors of cyclic nucleotide phosphodiesterase in the rat uterus]. / Proizvodnye aminobenzoinoi kisloty kak spetsificheskie ingibitory fosfodiésterazy tsiklicheskikh nukleotidov matki krys.

It is shown, that p-aminobenzoic acid and its derivatives (p-acetylaminobenzoic acid and p-aminobenzoic acid hydrazide) in the concentration of 10(-6) M are the potent inhibitors (40% below the control specimens) of the phosphodiesterase activity of cyclic nucleotides in the soluble fraction of the adult rat uterus. These drugs exerted no action on the adenylate cyclase activity in membrane fractions. The inhibition is only specific to the uterus enzyme and is not revealed for other tissues. The inhibition is found to be of incompetitive character Ki for p-aminobenzoic acid hidrazide being equal to 3.2 microM.

[Toxicity of para-aminobenzhydrazide and its influence on nucleic acid biosynthesis in cultures of normal and tumor cells]. / Toksichnost' para-aminobenzgidrazida i ego vliianie na biosintez nukleinovykh kislot v kul'turakh normal'nykh i opukholevykh kletok.

We have investigated cytotoxic action of p-aminobenzhydrazide and its influence on biosynthesis of nucleic acids in cultures of intact cells, tumor cells and intact cells stimulated by phytohemagglutinin. p-Aminobenzhydrazide is considered as a representative of hydrazine's derivatives (in particular, of hydrazine sulphate). We compare its action with that of a typical cytotoxic agent such as iododeoxyuridine. We have found that p-aminobenzhydrazide influences biosynthesis of nucleic acids in the same way as iododeoxyuridine. However it acts toxically on tumor cells though it is not toxic for intact cells so that its action is different as compared to that of cytotoxic agents. Specific toxic action of aminobenzhydrazide on tumor cells may be due to the enhancement of antitumor activity substances of this compound and absence of such enhancement of side toxic effects.

[The cyclic nucleotide system in various sections of the dog myocardium in experimental infarction]. / Issledovanie sistem tsiklicheskikh nukleotidov razlichnykh otdelov miokarda sobak pri éksperimental'nom infarkte.

Distinct increase and then decrease in content of cyclic nucleotides was observed in dog myocardium ventricles and auricles within early periods of heart infarction (10 min-4 hrs). Within a day after ligation of artery the ratio cAMP/cGMP was considerably decreased as a result of activation of guanylate cyclase and cAMP-phosphodiesterase as well as due to a decrease in activity of adenylate cyclase. Acute ischemia of small area of the heart left ventricle caused impairment of cyclic nucleotide metabolism in all the heart muscle.

[Effect of chemotherapy on the nucleoside phosphate kinase activity in experimental tumors]. / Vliianie khimioterapii na nukleozidfosfatkinaznuiu aktivnost' éksperimental'nykh opukholei.

In animals with experimental transplantable tumors, an effective treatment with antitumor compounds brought about interrelated changes in nucleoside phosphate kinase activity. The decrease in thymidine phosphate kinase activity was as a rule matched by an increase in that of uridine phosphate kinase. Consequently, "thymidine kinase-uridine kinase" shunt responsible for thymidine-uridine interconversion was suggested, which is switched on when the homeostasis of tumor cells is disturbed. In treatment of tumor-bearing animals, the effective dosage of antitumor drugs was considerably decreased due to a combination of the said compounds (inhibiting nucleoside kinases) or with azauridine which inhibits uridine monophosphate synthesis from orotidine-5'-phosphate.

[Effect of treatments of different modalities on the nucleoside phosphate kinase activity of normal and neoplastic cells]. / Vliianie vozdeistvii razlichnoi prirody na aktivnost' nukleozidfosfatkinaz normal'nykh i opukholevykh kletok.

The activity of nucleoside phosphate kinases was studied in experimental transplantable tumours under chemotherapy, in the liver of normal rats treated with hepatocarcinogens, or in human lung tumours after irradiation. The above factors have been found to increase the activity of uridine phosphate kinase, reducing at the same time the activity of thymidine phosphate kinase. The data suggest the existence of an unknown regulatory mechanism responsible for the normal levels of uridylates and thymidylates, thymidine kinase and uridine kinase shunt.

[Induction of acetylation in rats by pharmacological agents]. / Induktsiia atsetilirovaniia u krys s pomoshch'iu farmakologicheskikh sredstv.

Influence of oestron, tetracycline, reopyrine and phenobarbital on acetylation of sulphadimidine was studied in white female rats. Administration of the above-mentioned drugs caused an increase in the rate of acetylation, which reached the maximal values within the 2-5 days after the last day of administration.

[Potentiation of the antitumor activity of dioxadet by antiestrogen para-aminobenzhydrazide in a model of ovarian ascites tumor]. / Potetntsirovanie protivoopukholevogo deistviia dioksadéta antiéstrogenom--paraaminobenzgidrazidom na modeli astsitnoi opukholi iaichnika.

Experiments on rats with transplantable ascitic tumor of the ovary showed an antiestrogen--para-aminobenzhydrazide--to potentiate the antitumor effect of dioxadet. The mechanism of para-aminobenzhydrazide action is discussed.

[Effect of antiestrogen and antiandrogen derivatives of acylhydrazines on properties of nucleoside triphosphatases and adenyl nucleotide content of nuclei of normal and tumor cells]. / Deistvie antiéstrogenov i antiandrogenov iz klassa atsilgidrazinov na svoistva nukleozidtrifosfataz i na soderzhanie adenilovykh nukleotidov v iadrakh normal'nykh i opukholevykh kletok.

Influence of antiestrogen and antiandrogen derivatives of acylhydrazine, potentiating the antitumoral effect of cytostatics, on properties of nucleoside triphosphatases (NTPases), adenylate content in nuclea of normal and tumoral cells was studied. It was shown that acylhydrazines activated specifically the intranuclear NTPase of normal and tumoral cells. Activity of nuclear membrane-linked NTPases from liver cells was also increased after administration of acylhydrazines, sex hormones or phenobarbital. The increase in activity of intranuclear NTPase (namely ATPase) correlated with decrease of adenylates (ADP, ATP) in nuclea isolated from tumors after simultaneous treatment with acylhydrazines and thiophosphamide. Distinct increase in sensitivity of tumoral cell DNA to the effect of these alkylating preparations appear to be due to noncompensated decrease in content of ATP.

[Acid phosphatase isoenzyme composition of the lysosomes of normal and tumor cells]. / Issledovanie izofermentnogo sostava kisloi fosfatazy lizosom normal'nykh i opukholevykh kletok.

Heterogeneity of acid phosphatase in lysosomes of the rat's liver and the Zhaidel hepatoma was studied by the DEAE-cellulose chromatography. It is found that different substrates are hydrolyzed by different molecular forms of the enzyme. It is suggested that variability in the increase of the enzyme activities, measured with different substrates under alteration of lysosomes, may be due to the heterogeneity of molecular forms of acid phosphatase.

[Sex differences in the effect of acylhydrazines on temperature and pain threshold and in pharmacokinetics and tissue distribution]. / Polovye razlichiia v deistvii atsilgidrazinov na temperaturu, bolevoi porog, v pharmakokinetike i tkanevom raspredelenii.

It was shown that acylhydrazines derivatives display high sex selectivity during the action on normal or elevated temperature and pain threshold. Tissue distribution and the pharmacokinetics of 125I- or 131-I-p-aminobenzhydrazide in the blood of males and females were different. It is assumed that essential differences in the structure of cell membranes of males and females underlie the sex differences in the pharmacological effects of acylhydrazines.

[Selective action of hydrazine sulfate in combination with thiophosphamide on tumor cell mitochondria]. / Izbiratel'noe deistvie gidrazinsul'fata v sochetanii s tiofosfamidom na mitokhondrii opukholevykh kletok.

Hydrazine sulfate significantly potentiated antitumor effect of thiophosphamide in experiments on rats with Walker's tumor. The treatment with hydrazine sulfate (60 mg/kg) plus thiophosphamide (1 mg/kg) resulted in suppression of tumor growth up to 90%, the dosage of thiophosphamide being therapeutically ineffective. Following hydrazine sulfate treatment, the activity (pH: 7.0-7.5-7.75) derived from tumors doubled, as compared with control. Similar results were obtained with enzymatic preparations. The activities of DNP-stimulated ATPase and solubilized enzymes in rat liver were not influenced by treatment.