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Biomedical subjects

M Novotny

Publications and source records attributed to M Novotny.

At least 73 records · Page 4Linked to original sources

Nitrogen-sensitive thermionic detection in microcolumn liquid chromatography.

The dual-flame thermionic detector for microcolumn liquid chromatography has been improved and optimized for nitrogen sensitivity. The total column effluent is concentrically nebulized and aspirated directly into an air-hydrogen diffusion flame, while detection limits of 1.4 X 10(-11) g nitrogen/sec at the maximum of a Gaussian peak are achieved. Detection linearity spans three orders of magnitude. An example of the analysis of underivatized barbiturate standards is provided.

Barbiturates↗

Synthetic pheromones that promote inter-male aggression in mice.

Two volatile constituents of male mouse urine, dehydro-exo-brevicomin and 2-(sec-butyl)-dihydrothiazole, have been found active in bioassays of inter-male aggressive behavior. The two synthetic compounds act synergistically when added to castrated male urine but not when added to water, and they provoke fighting that is quantitatively and qualitatively comparable to that elicited by intact male urine.

Aggression↗

New thermionic detector utilizing orthogonal nebulization for capillary column liquid chromatography.

A new version of the previously studied phosphorus-sensitive, dual-flame thermionic detector has been developed for microcolumn liquid chromatography. The total column effluent is orthogonally nebulized and aspirated directly into a primary air-hydrogen diffusion flame. Phosphorus compounds with molecular weights extending beyond 500 a.m.u. are then selectively detected by measuring the conductivity of the secondary flame in the presence of a rubidium silicate bead. The sensitivity was found to be 1.36 X 10(-11) g phosphorus/sec at the maximum of a Gaussian peak, and the signal increased linearly with concentration over 2 orders of magnitude for dilute samples. Possible mechanisms accounting for the negative orientation of the signal and for the limited dynamic range are discussed.

Chemical Phenomena↗

Volatile constituents of wolf (Canis lupus) urine as related to gender and season.

The volatile constituents of wolf urine were examined via capillary gas chromatography and compared among male, female, and castrate male. Several compounds including methyl isopentyl sulfide, 3,5-dimethyl-2-octanone, and acetophenone were clearly associated with the gender of the animal and many displayed a seasonal dependence. In addition, 2 long-chain aldehydes isolated from urine samples by an HPLC procedure also correlated with the endrocrine status of the animal.

Animals↗

Effects of starvation and refeeding on the excretion of urinary steroid metabolites in mice with different genetic background.

Gas chromatographic steroid metabolic profiling procedures have been applied to investigations of the effects of starvation and refeeding in mice. Urinary steroid metabolites were quantitatively followed during the starvation-refeeding experiments for mice with different genetic backgrounds. Some quantitative alterations were noted for certain congenic strains of mice. The metabolites which exhibited such quantitative variations were tentatively identified by means of combined gas chromatography-mass spectrometry.

Animals↗

New biochemical separations using precolumn derivatization and microcolumn liquid chromatography.

Microcolumn liquid chromatography with slurry-packed capillary columns has been used to resolve mixtures of biologically important steroids and prostaglandins. In order to enhance detection sensitivity, the samples are first derivatized with a suitable chromophore-yielding agent. Hydroxy steroids were derivatized with either benzoyl chloride or 7-(chlorocarbonylmethoxy)-4-methylcoumarin, while Dns hydrazine was employed to react with the ketonic groups of certain steroidal conjugates. Bile acids can also be derivatized with bromomethylcoumarin to yield fluorescent products. The use of microcolumns permits both a high degree of component resolution and enhanced detection sensitivity.

Benzoates↗

Pharmacological activity of the basic fraction of marihuana whole smoke condensate alone and in combination with delta-9-tetrahydrocannabinol in mice.

This basic fraction (BF) of marihuana whole smoke condensate was subjected to pharmacological testing in males, Swiss-Webster mice. In a general pharmacological activity screen looking at behavioral, neurologic, and autonomic parameters, BF, at iv doses of 5, 10, and 20 mg/kg, caused impairment of visual placing, increase in tail pinch response, decrease in tail elevation, and induction of piloerection. These effects, although statistically significant, were slight and not consistently dose dependent. In a second study with doses ranging from 10 to 29 mg/kg, BF caused a decrease in spatial locomotion, rearing behavior, and urination incidence. In a third study, body temperatures of mice were measured periodically for 2 hr following administration of BF (1.2, 2.4, and 4.8 mg/kg) alone or in combination with 1.0 mg/kg delta-9-tetrahydrocannabinol (THC). BF did not alter body temperature, nor did it affect THC-induced hypothermia. These results, although suggesting that the basic fraction of marihuana whole smoke condensate has pharmacological activity in mice, offers little evidence for the presence of highly active compounds.

Animals↗

Chromatographic profiling of urinary volatile and organic acid metabolites of normal and diabetic C57BL/Ks mice.

Capillary gas chromatography and gas chromatography-mass spectrometry were used to examine the urinary volatile and organic acid metabolites in normal and diabetic C57BL/Ks male mice. Quantitative differences in the excretion of these metabolites were assessed in the animals from 5 to 24 weeks of age. Statistically significant differences were examined with respect to known metabolic abnormalities in the diabetic animals and to the possible toxic effects of elevated levels of certain metabolites. A number of aldehyde metabolites and aromatic acids, as well as most other organic acids, were found at consistently higher levels in diabetic urine. Several ketone metabolites, linalool, and 2-sec.-butylthiazoline were found at consistently low levels throughout the study.

Aging↗

Volatile compounds associated with estrus in mouse urine: potential pheromones.

Female mice that had been made estrous through hormone implantation excreted in their urine significantly enhanced levels of n-pentyl acetate, cis-2-penten-1-yl acetate, p-toluidine, 2-heptanone, and 3 unsaturated ketones. The relationship of these volatiles to a signaling function of the estrous urine is postulated. Structural elucidations of these compounds were carried out through capillary gas chromatography/mass spectrometry and the synthesis of authentic samples.

Animals↗

Identification of a testosterone-dependent unique volatile constituent of male mouse urine: 7-exo-ethyl-5-methyl-6,8-dioxabicyclo[3.2.1]-3-octene.

Investigations regarding the chemical composition of the volatiles in male mouse urine have recently enabled the structural elucidation of a hitherto unreported urinary component, 7-exo-ethyl-5-methyl-6,8-dioxabicyclo[3.2.1]-3-octene. This compound's uniqueness to mouse urine and its dependence on testosterone levels in the male suggest its probable role as a mouse pheromone or pheromone adjuvant.

Animals↗

Urinary profiles of volatile and acid metabolites in germfree and conventional rats.

Qualitative and quantitative differences in the urinary excretion of volatile and acidic metabolites in germfree and conventional rats were examined by capillary gas chromatography and gas chromatography/mass spectrometry. A number of carbonyl compounds, including several short-chain aliphatic ketones and acetophenone, were higher in the conventional urines, while many heterocyclic compounds (furan derivatives, benzothiazole and others) were lower. Both qualitative and quantitative differences were observed in the urinary excretion of acidic metabolites. Three meta-hydroxy phenolic acids appeared only in the conventional rat urines, while levels of many other aromatic and aliphatic acids were also higher.

Animals↗

Observation of an organism found in patients with gestational trophoblastic disease and in patients with toxemia of pregnancy.

This is an initial descriptive report of observations of multiple forms of an organism found in patients with gestational trophoblastic disease and in patients with preeclampsia-eclampsia. The worm-like forms most frequently observed have an average length of 1.0 to 1.5 mm. Larva-like forms have an average length of 150 mu; primordial eggs and egg-like forms in developmental stages range from 7 to 43 mu in diameter; and sperm-like forms are 3.5 mu or slightly smaller in size. These forms have been observed in contact smears prepared from 3 ml samples of peripheral circulating blood from both groups of patients, from trophoblastic tumor tissue, from contact smears prepared from placentas of patients with preeclampsia-eclampsia, and from umbilical cord blood of infants delivered of patients with preeclampsia-eclampsia. The various forms of this organism share morphologic characteristics of several orders of helminths, i.e., hookworms, roundworms and tapeworms. The taxonomy of these forms has not yet been determined. Until the time of taxonomic classification, the various forms will be referred to as Hydatoxi lualba. We have experimental evidence that this organism has biologic activity in BALB/c mice and in beagle dogs.

Animals↗

Quantitative alterations of steroid urinary profiles associated with diabetes mellitus.

Capillary gas chromatography was used for the acquisition of quantitative metabolic profiles of urinary steroids from normal subjects and diabetic patients. Structures of 70 steroid metabolites have been assigned tentatively through mass spectrometry. Quantitative differences between the groups of normal and pathological samples (both males and females) are seen primarily for androsterone, etiocholanolone, dehydroepiandrosterone, 11-oxygenated 17-ketosteroids, corticosteroid metabolites, and a newly discovered metabolite, recently identified as a C26 pentol. The only significant difference between two different age groups of normal males was shown by androsterone.

17-Ketosteroids↗