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PubMed2001

Enzymatically enantioselective hydrolysis of prochiral 1,3-diacyloxyglycerol derivatives.

An enzymatically enantioselective ester hydrolysis of prochiral 1,3-diacyloxy-2-substituted-2-propanol to chiral 1-acyloxy-2,3-propanediol was studied. The (R)-monoester was prepared by selection of a suitable lipase and alkyl chain length of the substrate diester. Lipase D from Rhizopus delemer gave (R)-1-isobutyryloxy-2-(2,4-difluorophenyl)-2,3-propanediol with 97%ee and 87% yield at 15 degrees C and pH 5.5. The (R)-monoester is a key intermediate of azole antifungal agents.

Biochemistry↗
PubMed1983

Physiochemical studies on indocyanine green: molar lineic absorbance, pH tolerance, activation energy and rate of decay in various solvents.

Physiochemical studies were carried out on the tricarbocyanine dye indocyanine green in biological fluids and organic solvents. The molar lineic absorbance epsilon of the compound was highest in organic solvents (methanol, 1.2-propanediol, dimethylformamide) and bile, but lowest in water and duodenal fluid. Indocyanine green remained stable in methanol and bile (t1/2 greater than 1 year) but was rapidly decomposed to a colourless derivative in duodenal fluid and distilled water (t1/2 3.6 days and 1.4 days, respectively). It was thermostable (120 degrees C) in methanol and 1.2-propanediol but thermolabile in water and dimethylformamide where the activation energy for the decomposition reaction was low. At ambient temperature (20 degrees C) indocyanine green was particularly labile at pH less than 5 and pH greater than 11. The rate of decay of indocyanine green in various solvents indicated that the rate limiting step in the decay process was either a first or zero order reaction.

Chemical Phenomena↗
PubMed1984

Two-step freezing of two-cell rabbit embryos after partial dehydration at room temperature.

The effect of rapid freezing and thawing on the survival of 2-cell rabbit embryos was examined. When embryos in 2.2 M-propanediol were directly plunged from room temperature to liquid nitrogen some of them survived after thawing (8%) but only if they had been pretreated by exposure to an impermeable solute, sucrose, that makes the blastomeres shrink osmotically before cooling. High survival (77-88%) in vitro was obtained when pretreated embryos were first held at -30 degrees C for 30-240 min before immersion into liquid nitrogen. Transfer of such frozen-thawed embryos gave a survival rate to live young similar to that obtained with controls (26% and 32% respectively). DMSO was less effective than propanediol; only 2 out of 38 sucrose-pretreated frozen-thawed embryos developed in vitro. The present work shows that a combination of partial dehydration of blastomeres at room temperature with their permeation by a cryoprotective agent offers a simple method for successful rapid freezing and thawing of rabbit embryos.

Animals↗
PubMed1976

A search for the best buffer to use in assaying human lactate dehydrogenase with the lactate-to-pyruvate reaction.

Highly purified human lactate dehydrogenases I and V were assayed in 17 different buffers, at a variety of reaction pH's. Diethanolamine and 2-amino-2-methyl-1,3-propanediol provided the best measurements of the enzyme, assayed lactate-to-pyruvate. However, the commercial preparation of 2-amino-2-methyl-1,3-propanediol contained insoluble matter and was relatively expensive. All of the four buffers nowmost commonly used were found to present difficulties. Glycine and pyrophosphate were inhibotory tolactate dehydrogenase activity with increasing buffer concentration. 2-Amino-2-methyl-1-propanol had three major disadvantages: it is chemically unstable during reagent preparation; activity is dependent on buffer concentration; and the pH optima for isoenzymes I and V are vastly different. The pKa of tris(hydroxymethyl)aminomethane is 8.0 at 30 degrees C, whereas to measure total activity the reaction pH should be greater than 8.5; thus tris(hydroxymethyl)aminomethane has limited buffering capacity at the reaction pH.

Buffers↗
PubMed2000

The use of 1H-NMR spectroscopy and refractometry for investigation of the distribution of nonelectrolytes of N-alcohol series between human red blood cells and extracellular medium.

Comparative analysis of 1H NMR spectroscopy and refractometry with respect to their application for investigating the distribution of nonelectrolytes of n-alcohol series (ethanol, 1,2-propanediol, glycerol) and polyethylene glycols (PEGs) with molecular masses of 400, 600, 1500 between human erythrocytes and extracellular medium was performed. The distribution coefficients (Q) for solutions of ethanol, 1,2-propanediol, glycerol, PEG-400, PEG-600 and PEG-1500 were obtained. The Q values decreased with the increase in the nonelectrolyte molecular mass from 1.23+/-0.12 for ethanol to 0.40+/-0.08 for PEG-1500 (1H NMR spectroscopy) and from 2.6+/-0.12 for ethanol to 0.23+/-0.03 for PEG-1500 (refractometry). It was shown that 1H-NMR high-resolution spectroscopy ensures more precise determination of Q values for nonelectrolytes with low molecular masses; for PEGs with high molecular masses, the accuracy of Q value calculation by this method was about 20%. On the contrary, refractometry can be used for investigating substances with high molecular masses; the error of Q value determination for solution of low-refractive substances, such as ethanol, may be more than 50%.

Electrolytes↗
PubMed2001

Metabolism and disposition of alpha-methylstyrene in rats.

alpha-Methylstyrene (AMS) is a volatile hydrocarbon used primarily in the production of specialty polymers and resins. In the present study, the tissue distribution, metabolism, and excretion of [(14)C]AMS was investigated in male rats after i.v. administration (11 mg/kg). Over 90% of AMS administered intravenously to rats was excreted in 72 h. Urinary excretion accounted for 86% of the administered dose, volatile breath and feces accounted for 2.2 and 1.9%, respectively, and elimination as carbon dioxide was negligible. Metabolites were isolated from rat urine following a high oral dose of AMS (1000 mg/kg) and characterized using gas chromatography/mass spectrometry and NMR spectrometry. The metabolites were 2-phenyl-1,2-propanediol (3% of urinary radioactivity) and its glucuronide (50%), atrolactic acid (27%), S-(2-hydroxy-2-phenylpropyl)-N-acetylcysteine (13%), and 2-phenylpropionic acid (1%); the glucuronides and mercapturates were each conjugated on the methylene carbon beta to the ring. The presence of both of the diastereomeric isomers of the mercapturates and of the glucuronides suggested that the initial epoxidation of AMS was not stereoselective and proceeded with addition of active oxygen to yield enantiomeric epoxides. Incubation of AMS with human liver slices produced the same metabolites as those excreted in rat urine, with 2-phenyl-1,2-propanediol present as the predominant metabolite after 5 h of incubation.

Animals↗
PubMedDate not supplied

A simple capacitive cell for the measurement of liquids dielectric constant under transient thermal conditions.

A simple device for the measurement of the complex dielectric permittivity of liquids in various thermodynamic states has been developed. It uses a cylindrical aluminium capacitor of a type currently applied in tuning antenna circuits. The capacitor is filled with the liquid solution under study. A comparison of its capacity is made with that of the nitrogen filled capacitor tested under the same thermal conditions. This comparison allows the determination of the real and imaginary part of the solutions permittivity as a function of temperature (between 150 and 300 K) and frequency (between 100 Hz to 2 MHz). After validating the technique with pure glycerol and pure 1,2-propanediol, spectroscopic measurements have been undertaken on pure and diluted 1,2-propanediol in water. Due to the low heat capacity and the high thermal conductivity of the capacitor, cooling rates of 40 K/min have been achieved inside the solution, allowing measurements in the supercooled liquid and vitreous states. Results are presented and discussed in terms of relaxation and the physical states of the sample. By selecting the required thermal conditions, this device permits the observation of thermal transitions, such as ice crystallisation, and measurements to be conducted in the unstable supercooled liquid state. These measurements are necessary in the development of an effective electromagnetic warming device for vitrified cryoprotective solutions.

Electric Conductivity↗
PubMed1989

NTP Toxicology and Carcinogenesis Studies of Pentaerythritol Tetranitrate (CAS No. 78-11-5) with 80% D-Lactose Monohydrate (PETN, NF) in F344/N Rats and B6C3F1 Mice (Feed Studies).

Pentaerythritol tetranitrate (PETN, NF) is a drug used to prevent angina pectoris. PETN without a lactose stabilizer is used as an explosive. NTP Toxicology and Carcinogenesis studies were conducted by administering PETN, NF, to groups of F344/N rats and B6C3F1 mice of each sex once by gavage or in feed for 14 days, 13 or 14 weeks, or 2 years. The PETN component was greater than 99% pure. Genetic toxicology studies were conducted with Salmonella typhimurium and Chinese hamster ovary (CHO) cells. Fourteen-Day and Thirteen-Week Studies: All rats and mice lived to the end of the 14-day studies (dietary concentrations up to 50,000 ppm). Final mean body weights of dosed and control rats were comparable. The final mean body weight of female mice that received 50,000 ppm was 13% lower than that of controls. No clinical signs or toxic lesions were attributed to PETN, NF, administration. All rats and mice lived to the end of the 13-week (mice) and 14-week (rats) studies (dietary concentrations up to 50,000 ppm). Final mean body weights of dosed and control rats and mice were similar, although weight gains of female rats at 25,000 and 50,000 ppm were less than that of controls. The nitrite level in urine of rats and methemoglobin levels in whole blood of rats and mice were not affected by administration of PETN, NF. An adenoma of the Zymbal gland was seen in a female rat that received 50,000 ppm. A hepatocellular adenoma was seen in a female mouse that received 50,000 ppm. Based on these results and the NTP convention of limiting concentrations in 2-year feed studies to 5% of the diet, the 2-year studies were conducted by administering 0, 25,000 or 50,000 ppm PETN, NF, in feed for 104 weeks to groups of 50 male rats and for 103 weeks to groups of 49 or 50 mice of each sex. Groups of 50 female rats were given feed containing 0, 6,200, or 12,500 ppm PETN, NF, for 104 weeks. Body Weight and Survival in the Two-Year Studies: Mean body weights of high dose male rats were 2%-9% lower than those of controls throughout the study; body weights of all groups of female rats were similar. No significant differences in survival were observed between any groups of rats of either sex (male: control, 23/50; low dose, 29/50; high dose, 29/50; female: 33/50; 33/50; 31/50). Mean body weights of dosed and control mice were similar. The survival of both groups of dosed male mice was significantly greater than that of the controls (26/49; 38/50; 38/50). No significant differences in survival were observed between any groups of female mice (38/50; 30/50; 38/50). Nonneoplastic and Neoplastic Effects in the Two-Year Studies: No nonneoplastic lesions were attributed to PETN, NF, administration in rats or mice. Neoplasms of the Zymbal gland occurred in dosed male (control, 0/49; low dose, 3/45; high dose, 2/41) and dosed female (0/36; 1/37; 3/35) rats. The historical incidence of these neoplasms is 1% +/- 2% in untreated males and 0.6% +/- 1% in females. At no site was a significantly increased incidence of neoplasms observed in dosed male or female mice. Genetic Toxicology: PETN, NF, was not mutagenic in S. typhimurium strains TA98, TA100, TA1535, or TA1537 when tested with or without exogenous metabolic activation (S9). When tested for cytogenetic effects in cultured CHO cells, PETN, NF, induced sister chromatid exchanges (SCEs) in the presence and absence of metabolic activation; no induction of chromosomal aberrations was observed in CHO cells with or without activation. Audit: The data, documents, and pathology materials from the 2-year studies of PETN, NF, have been audited. The audit findings show that the conduct of the studies is documented adequately and support the data and results given in this Technical Report. Conclusions: Under the conditions of these 2-year feed studies, there was equivocal evidence of carcinogenic activity of PETN, NF, for male and female F344/N rats, based on a marginal increase in neoplasms of the Zymbal gland. Female rats might have tolerated a higher dose. There was no evidence of carcinogenic activity of PETN, NF, forher dose. There was no evidence of carcinogenic activity of PETN, NF, for male or female B6C3F1 mice fed diets containing 25,000, or 50,000 ppm for 2 years. No nonneoplastic lesions were attributed to PETN, NF, administration. Synonyms for PETN: 2,2-bis((nitrooxy)methyl)-1,3-propanediol dinitrate (ester); 2,2-bisdihydroxy-methyl-1,3-propanediol tetranitrate; niperyt; nitropentaerythritol; pentaerythrityl tetranitrate; penthrit Trade Names for PETN, NF: Angitet; Cardiacap; Dilcoran-80; Dipentrate; Hasethrol; Lentrat; Metranil; Mycardol; Neo-Corovas; Nitropenta; Nitropenton; Pentafin; Pentanitrine; Pentitrate; Pentral 80; Pentrite; Pentritol; Pentryate; Peridex; Pergitral; Peritrate; Perityl; Prevangor; Quintrate; Subicard; Terpate; Vasodiatol

Journal Article↗
PubMed1990

NTP Toxicology and Carcinogenesis Studies of Glycidol (CAS No. 556-52-5) In F344/N Rats and B6C3F1 Mice (Gavage Studies).

Glycidol is a viscous liquid that is used as a stabilizer in the manufacture of vinyl polymers, as an additive for oil and synthetic hydraulic fluids, and as a diluent in some epoxy resins. NTP Toxicology and Carcinogenesis studies were conducted by administering glycidol (94% pure, containing 1.2% 3-methoxy-1,2-propanediol, 0.4% 3-chloro-1,2-propanediol, 2.8% diglycidyl ether, and 1.1% 2,6-dimethanol-1,4-dioxane) in water by gavage to groups of F344/N rats and B6C3F1 mice of each sex for 16 days, 13 weeks, or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, Chinese hamster ovary (CHO) cells, Drosophila melanogaster, and the bone marrow of male B6C3F1 mice. Sixteen-Day Studies: Glycidol doses for groups of five rats or five mice of each sex ranged from 37.5 to 600 mg/kg; vehicle controls received distilled water. All rats that received 600 mg/kg died between days 3 and 13. Edema and degeneration of the epididymal stroma, atrophy of the testis, and granulomatous inflammation of the epididymis occurred in males that received 300 mg/kg. All mice that received 600 mg/kg and two males and two females that received 300 mg/kg died by day 4 of the studies. Focal demyelination in the medulla and thalamus of the brain occurred in all female mice that received 300 mg/kg. Thirteen-Week Studies: Doses for groups of 10 rats ranged from 25 to 400 mg/kg, and doses for groups of 10 mice ranged from 19 to 300 mg/kg; vehicle controls received distilled water. All rats that received 400 mg/kg died by week 2; three males and one female that received 200 mg/kg died during weeks 11-12. Final mean body weights of male rats that received 50, 100, or 200 mg/kg were 96%-85% that of vehicle controls; final mean body weights of female rats receiving the same doses were 95%-89% that of vehicle controls. Sperm count and sperm motility were reduced in male rats that received 100 or 200 mg/kg. Necrosis of the cerebellum, demyelineation in the medulla of the brain, tubular degeneration and/or necrosis of the kidney, lymphoid necrosis of the thymus, and testicular atrophy and/or degeneration occurred in rats that received 400 mg/kg. All mice that received 300 mg/kg died by week 2; deaths of mice that received 150 mg/kg occurred during weeks 4-8 for males and weeks 1-5 for females. Mean body weights of chemically exposed mice surviving to the end of the studies were generally 90%-94% those of vehicle controls. Sperm count and sperm motility were reduced in dosed male mice. Compound-related histopathologic lesions included demyelination of the brain in males and females that received 150 or 300 mg/kg, testicular atrophy in males at all doses, and renal tubular cell degeneration in male mice that received 300 mg/kg. Based on reduced survival, reduced weight gain, and histopathologic lesions in the brain and kidney in rats that received 200 or 400 mg/kg and on reduced survival and histopathologic lesions of the brain in mice that received 150 or 300 mg/kg, doses selected for the 2-year studies of glycidol were 37.5 and 75 mg/kg for rats and 25 and 50 mg/kg for mice. Body Weights and Survival in the Two-Year Studies: Mean body weights of chemically exposed male rats generally ranged from 80% to 94% of those of vehicle controls, and mean body weights of chemically exposed female rats were from 90% to 97% those of vehicle controls. Mean body weights of chemically exposed male mice were similar to those of vehicle controls; mean body weights of chemically exposed female mice were 79%-95% of those of vehicle controls. Virtually all male and female rats that received glycidol died or were killed in a moribund condition as a result of the early induction of neoplastic disease (final survival--male: vehicle control, 16/50; low dose, 0/50; high dose, 0/50; female: 28/50; 4/50; 0/50). Survival of vehicle control male rats was lower than that usually observed; however, specific causes of deaths could not be determined. The survival of male mice and low dose female mice was similar to that of vehicle controls; survival of female mice that resurvival of male mice and low dose female mice was similar to that of vehicle controls; survival of female mice that received 50 mg/kg was lower than that of vehicle controls after week 101 (final survival--male: 33/50; 25/50; 27/50; female: 29/50; 27/50; 17/50). Nonneoplastic and Neoplastic Effects in the Two-Year Studies: Chemical-related nonneoplastic lesions in both rats and mice included hyperkeratosis and epithelial dysplasia of the forestomach. Fibrosis of the spleen was also present in rats of each sex, and cysts of the preputial gland and kidney were present in male mice. Exposure to glycidol induced dose-related increases in the incidences of neoplasms in numerous tissues in both rats and mice (see summary table on page 5 of the Technical Report). In male rats, mesotheliomas arising in the tunica vaginalis and frequently metastasizing to the peritoneum were considered the major cause of early death. Early deaths in female rats were associated with the presence of mammary gland neoplasms. Genetic Toxicology: Glycidol was mutagenic in a variety of in vitro and in vivo short-term tests. Mutagenic activity was observed in S. typhimurium strains TA97, TA98, TA100, TA1535, and TA1537 exposed to glycidol with and without exogenous metabolic activation. Glycidol was positive in the absence of exogenous metabolic activation in the mouse lymphoma assay for induction of trifluorothymidine resistance in L5178Y/TK cells; it was not tested with activation. In cytogenetic tests with CHO cells, glycidol induced both sister chromatid exchanges and chromosomal aberrations in the presence and absence of exogenous metabolic activation. Glycidol induced sex-linked recessive lethal mutations and reciprocal translocations in the germ cells of male D. melanogaster exposed by feeding. The incidence of micronucleated polychromatic erythrocytes was increased in the bone marrow of male B6C3F1 mice administered glycidol by intraperitoneal injection. Conclusions: Under the conditions of these 2-year gavage studies, there was clear evidence of carcinogenic activity of glycidol for male F344/N rats, based on increased incidences of mesotheliomas of the tunica vaginalis; fibroadenomas of the mammary gland; gliomas of the brain; and neoplasms of the forestomach, intestine, skin, Zymbal gland, and thyroid gland. There was clear evidence of carcinogenic activity for female F344/N rats, based on increased incidences of fibroadenomas and adenocarcinomas of the mammary gland; gliomas of the brain; neoplasms of the oral mucosa, forestomach, clitoral gland, and thyroid gland; and leukemia. There was clear evidence of carcinogenic activity for male B6C3F1 mice based on increased incidences of neoplasms of the harderian gland, forestomach, skin, liver, and lung. There was clear evidence of carcinogenic activity for female B6C3F1 mice, based on increased incidences of neoplasms of the harderian gland, mammary gland, uterus, subcutaneous tissue, and skin. Other neoplasms that may have been related to the administration of glycidol were fibrosarcomas of the glandular stomach in female rats and carcinomas of the urinary bladder and sarcomas of the epididymis in male mice. Synonym: 2,3-epoxy-1-propanol

Journal Article↗
PubMed1958

The present status of tranquilzing drugs.

TRANQUILIZING DRUGS MAY BE CLASSIFIED INTO FOUR GROUPS, ACCORDING TO CHEMICAL STRUCTURE: (1) Phenothiazine derivatives, (2) Rauwolfia alkaloids, (3) substituted propanediols or butanediols, and (4) diphenylmethane derivatives. The distinguishing features of tranquilizing drugs in contrast to conventional sedatives is that they calm without producing sleep and that their site of action in the central nervous system is predominantly subcortical. The principal sites of action are important regulating centers of the brain: thalamus, hypothalamus, reticular activating system and portions of the limbic system. Phenothiazine derivatives, besides being the most effective tranquilizers for treating severe emotional disorders, are also clinically useful for potentiating other analgesic or anesthetic drugs and for controlling vomiting. This rapidly growing group of drugs is of major importance in present-day psychopharmacologic therapy. Newer derivatives, especially of the piperazine type, appear to be highly effective as tranquilizers in low doses. They also produce fewer major complications from treatment. Rauwolfia alkaloids have decreased in importance in psychiatric use, but are still the basic drugs for treating hypertension. The substituted propanediols or butanediols are generally used as mild sedatives for less serious emotional disorders. The diphenylmethane derivatives, while chemically related, have a variety of pharmacologic actions which include sedation, stimulation, antihistaminic and anticholinergic effects. The ultimate role of these agents in the treatment of major emotional disorders, such as schizophrenic reactions, still is uncertain. However, the impetus these drugs have given to improved treatment of psychotic patients in mental hospitals has unquestionably been beneficial. The intensive attempts to determine their modes of action will very likely yield important advances in the understanding of possible neurophysiologic bases for mental illness.

Antipsychotic Agents↗
PubMed2003

Stereoselective oxidation of aliphatic diols and reduction of hydroxy-ketones with galactitol dehydrogenase from Rhodobacter sphaeroides D.

From the Rhodobacter sphaeroides mutant D a galactitol dehydrogenase (GDH) was isolated and characterized in an earlier investigation (1). The enzyme expressed activity with a wide spread substrate spectrum, like sugars, sugar alcohols, secondary alcohols or the corresponding ketones and it can be used for the production of the rare sugar L-tagatose by regioselective oxidation of galactitol (2). This study focuses on the preparation of optically pure aliphatic diols by oxidation of one enantiomer or stereospecific reduction of keto-alcohols and diketones. The oxidation of 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol and 1,2-hexanediol occurred highly specific with the S-enantiomer leaving the R-enantiomer of the diols in the reaction vessel. Also (S)-1,2,6-hexanetriol was oxidized by GDH to 1,6-dihydroxy-2-hexanone. The Km values of these reactions decreased with increasing length of the carbon chain. Reduction of hydroxyacetone or 1-hydroxy-2-butanone resulted in an excess of 93% (S)-1,2-propanediol and more than 98% of (S)-1,2-butanediol, respectively. The diketone 2,3-hexanedione was only reduced to (2R,3S)-2,3-hexanediol, one of the possible four configurations. The wide substrate spectrum on one hand and the selectivity in the reaction on the other hand make GDH a very interesting enzyme for the production of optically pure building blocks in the chemical synthesis of bioactive compounds.

Dihydroxydihydrobenzopyrenes↗
PubMed1992

Reduction of trioses by NADPH-dependent aldo-keto reductases. Aldose reductase, methylglyoxal, and diabetic complications.

The substrate specificities of human aldose reductase and aldehyde reductase toward trioses, triose phosphates, and related three-carbon aldehydes and ketones were evaluated. Both enzymes are able to catalyze the NADPH-dependent reduction of all of the substrates used. Aldose reductase shows more discrimination among substrates than does aldehyde reductase and is generally the more efficient catalyst. The best substrate for aldose reductase is methylglyoxal (kcat = 142 min-1, kcat/Km = 1.8 x 10(7) M-1 min-1), a toxic 2-oxo-aldehyde that is produced nonenzymatically from triose phosphates and enzymatically from acetone/acetol metabolism. D- and L-glyceraldehyde and D- and L-lactaldehyde are also good substrates for aldose reductase. The aldose reductase-catalyzed reduction of methylglyoxal produces 95% acetol, 5% D-lactaldehyde. Further reduction of acetol produces only L-1,2-propanediol. Acetol and propanediol are two products that accumulate in uncontrolled diabetes. Both acetol and methylglyoxal were compared with glucose for their abilities to produce covalent modification of albumin. All three of these carbonyl compounds reacted with albumin to produce modified proteins with new absorption and emission bands that are spectrally similar. Both methylglyoxal and acetol are much more reactive than glucose. A new integrative model of diabetic complications is proposed that combines the aldose reductase/polyol pathway theory and the nonenzymatic glycation theory except that emphasis is placed both on methylglyoxal/acetol metabolism and on glucose metabolism.

Acetone↗
PubMed1991

The survival and development rates in mouse embryo cryopreservation.

A research of mouse embryo cryopreservation was carried out in our department in order to establish the clinical service of human embryo cryopreservation. Mouse embryos were stored in glass vials using 1.5M propanediol (PROH) or 1.5M dimethyl sulfoxide (DMSO) as cryoprotectants and we used a modified four-step equilibration method to minimize osmolarity shock. We divided the 1490 embryos into two phases and compared phase 1 to phase 2. After achieving more sophisticated handling techniques and more accurate timing of each procedure, the survival rate (25% vs 59.8%) and stage advancing rate (5.2% vs 33.5%) were all improved in phase 2. The proportion of frozen embryos developing to hatched blastocysts was significantly increased from 14.5% to 56.7% in the 4-cell embryo groups compared to the 2-cell embryo groups. Two kinds of cryoprotectants were used in the 4-cell embryos and the results showed no difference in the post thaw survival rate but a better blastocystic development in the propanediol group (64.0% vs 41.5%). The results obtained from this study have encouraged us to initiate a major clinical trial of the technique in our IVF programs. Two pregnancies have been established upon the transfer of cryopreserved embryo and two normal healthy infants have already delivered at our hospital.

Animals↗
PubMed1990

Malignant transformation of mouse M2-fibroblasts by glycerol chlorohydrines contained in protein hydrolysates and commercial food.

Glycerol chlorohydrines, such as 3-chloro-1,2-propanediol and 1,3-dichloro-2-propanol, are present in commercial protein hydrolysates used for human nutrition. These compounds are genotoxic and 1,3-dichloro-2-propanol induced tumors in rats. Now it is reported that both compounds are active at inducing malignant transformation of mouse fibroblasts. Therefore, the carcinogenic risk to humans by exposure to these compounds contained in food is of concern. The investigation of the in vivo carcinogenic potential of 3-chloro-1,2-propanediol is urgently required to further evaluate the carcinogenic risk to exposed consumers.

Animals↗
PubMed1990

Ultrarapid freezing and thawing of hamster oocytes. Morphologic parameters, trypan blue staining and sperm penetration assay for evaluating survival.

Nine hundred sixteen hamster oocytes were cryopreserved with the ultrarapid freezing method using five different cryoprotective solutions: 3 mol/L dimethylsulphoxide (DMSO) plus 0.25 mol/L sucrose, 3 mol/L DMSO, 3 mol/L propanediol plus 0.25 mol/L sucrose, 3 mol/L propanediol and 10% glycerol. One hundred eighty fresh oocytes served as controls. The viability of the oocytes was evaluated using morphologic parameters, Trypan blue staining and the sperm penetration assay. The viability rates based on morphologic parameters and Trypan blue staining were 82.3%, 65.0%, 51.4%, 33.0% and 0%, respectively, as compared to 100% in the controls. The sperm penetration rates were 27.0%, 0%, 9.8%, 0% and 0%, respectively, as compared to 94-98% in the controls. Our results indicate that among the various cryoprotective solutions used for ultrarapid freezing, 3 mol/L DMSO plus 0.25 mol/L sucrose gave the best results, with a viability rate of 82.3% and a sperm penetration rate of 27%.

Animals↗
PubMed1975

The pH dependence of the hydrolysis of benzoyl-L-arginine ethyl ester in cooled mixed solvents.

Tables of protonic activity (paH) of a number of buffers, determined in mixed solvents and at subzero temperatures, are reported for the following media: water-1,2-propanediol, water-glycerol, and water-dimethylsulfoxide (50:50, in volume). These data with those previously reported allowed us to study enzymic reactions under these conditions. The paH dependence of the tryptic hydrolysis of benzoyl-L-arginine ethyl ester has been studied in the presence of organic solvents (methanol, ethylene glycol, 1,2-propanediol, glycerol, and dimethylsulfoxide, all 50% by volume) between 20 and -20 degrees. The results have allowed us to show the validity of our paH scales in mixed solvents. The paH profiles obtained under these conditions are similar to those observed in pure water at 20 degrees. They are shifted nevertheless by both solvent and temperature. Such shifts are interpreted in terms of the effects of solvents and temperature on pKES on the basis of the conclusions drawn from a study of the effect of these variables on small dissociable molecules. The results obtained under these conditions of solvents and temperature are consistent with the presence at the active site of the enzyme of a histidine residue, and thus provide, concerning the solvent effect, a direct verification of the method of Findlay et al. (Findlay, D., Mathias, A. P., and Rabin, B. R. (1962) Biochem. J. 85, 139-144). On the other hand, the large temperature interval provided by the low temperature procedure, allows us to vary significantly the pK of ionizable groups of the enzymes and thus makes possible their identification, on the basis of their enthalpy of ionization.

Arginine↗
PubMed1989

Cryopreservation of mouse embryos at -196 degrees C by vitrification.

Embryos (8-16 cell) were obtained from random bred albino mice (6-8 weeks old) that were induced to superovulate by injections of 5 I.U. PMSG and 5 I.U. hCG given 48 hr apart. Embryos were exposed to intracellular cryoprotecting medium (glycerol 10%, 1-2 propanediol 20% in PBS) for 10 min and then transferred to extracellular vitrification medium (25% glycerol, 25% 1-2 propanediol in PBS). Vitrification medium containing embryos, and diluent (1 M sucrose) were loaded in a straw and immediately plunged into liquid N2. After thawing at 20 degrees C, the contents of the straw were mixed by shaking (1 step dilution) and emptied in a petri dish. After 3 washings in culture medium the embryos were kept in CO2 incubator for further development. In 3-step dilution procedure the dilution of cryoprotectants was done in 0.5 and 0.25 M sucrose before culture. Embryos in 3-step dilution of cryoprotectants exhibited high survival as compared to 1-step dilution (20.23% vs 6.55%).

Animals↗
PubMed1989

Characterization of novel glycolipids from the giant cockroach (Blaberus colosseus).

A novel class of glycolipids, assigned the trivial name blaberosides, was isolated from whole head tissues of the giant cockroach (Blaberus colosseus). The class consists of two closely related families, blaberoside I and blaberoside II, each containing species differing by 26 atomic mass units. The structure of these gentiobiose-based glycoglycerolipids was elucidated by chromatographic behavior, nuclear magnetic resonance spectroscopy, mass spectrometry, and analysis of chemical degradation products and derivatives. Species in the blaberoside I family have been identified as 2-O-[6'-O-(6"-O-3-hydroxy-11-eicosenoyl-beta-D-glucopyranosyl)-bet a-D- glucopyranosyl]-3-(hexadecyloxy)-1-(3-hydroxy-11-eicosenoyl)-1,2-p ropanediol (blaberoside Ia) and 2-O-[6'-O-(6"-O-3-hydroxy-11-eicosenoyl-beta-D-glucopyranosyl)-bet a- D-glucopyranosyl]-3-(6-octadeceloxy)-1-(3-hydroxy-11-eicosenoyl )-1,2- propanediol (blaberoside Ib). Two smaller homologs of the blaberoside II family were discerned to be 2-O-[6'-O-(6"-O-3-hydroxy-11- eicosenoyl-beta-D-glucopyranosyl)-beta-D-glucopyranosyl]-3-(hex ade cyloxy)- 1,2-propanediol (blaberoside IIa), and 2-O-[6'-O-(6"-O-3-hydroxy-11-eicosenoyl-beta-D- glucopyranosyl)-beta-D-glucopyranosyl]-3-(4-octadeceloxy)-1,2-prop anediol (blaberoside IIb). These compounds are unique because they are animal origin glyceroglycolipids with a highly flexible gentiobiose backbone, and a beta-linkage of the carbohydrate to the glycerol ether at the 2 position rather than the usual 1 position.

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