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Biomedical subjects

J J Sullivan

Publications and source records attributed to J J Sullivan.

At least 73 records · Page 4Linked to original sources
PubMed1983

A critique of Theory Z.

Ouchi's Theory Z prescribes how employees should be motivated for increased productivity. Based on the theoretical work of Emile Durkheim, it views the modern large corporation as a communal alternative to the shortcomings of other institutions in industrial mass society. Ouchi's assertion that Japan is the industrial society in which Theory Z has flourished received limited support from research findings. Moreover, Ouchi's grounding of the theory in humanistic management seem unwarranted.

Efficiency↗
PubMed1983

High pressure liquid chromatographic determination of toxins associated with paralytic shellfish poisoning.

A high pressure liquid chromatographic procedure is described for assay of toxins associated with paralytic shellfish poisoning (PSP). The method is applicable to saxitoxin, neosaxitoxin, gonyautoxins I through IV, and their sulfocarbamoyl derivatives. Toxins are separated on a bonded phase cyano column and detected by fluorescence following alkaline oxidation (NH+4 and periodic acid). The utility of the HPLC procedure for research and monitoring is discussed.

Animals↗
PubMed1982

Metacyclogenesis of Trypanosoma cruzi in vitro: a simplified procedure.

A simplified procedure for obtaining high levels of infective, metacyclic trypomastigotes of a Brazilian strain of Trypanosoma cruzi in vitro is described. Epimastigotes cultured in Yaeger's Liver Infusion Tryptose Medium, when transferred to Grace's Insect Tissue Culture Medium (GMA) supplemented with 10% foetal bovine serum, yielded over 90% metacyclic forms. Decreasing or eliminating the serum from GMA adversely affected growth but did not decrease levels of transformation, thus providing a chemically defined culture system for analysing factors influencing metacyclogenesis of T. cruzi.

Animals↗
PubMed1981

A source of error in mutagen testing of foods.

Mutagenic compounds reported to be present in foods may be forming during the extraction process rather than during cooking or baking. In this study, the formation of mutagenic substances in biscuits was examined using in the extraction procedure either ammonium sulfate and ammonium hydroxide or sodium sulfate and sodium hydroxide. Compounds producing high mutagenic activity in Salmonella strains 1538 and TA 98 obtained from aqueous biscuit extracts containing ammonium ions. No mutagenic activity was observed in extracts from aqueous biscuit extracts containing sodium ions until some ammonium ions (NH4OH) were added. We suggest that ammonium sulfate and ammonium hydroxide not be used in the extraction procedure of food when studying mutagen formation.

Bread↗
PubMed1981

Effect of pH and ammonium ions on mutagenic activity in cooked beef.

Controversy surrounding the extraction procedure commonly used for isolating and concentrating mutagens from foods has resulted in a need for the re-examination of the reported mutagenicity in fried hamburgers. Using a procedure in which Na2SO4 and NaOH are substituted for (NH4)2SO4 and NH4OH respectively, mutagenic activity in extracts of hamburgers fried for 5 min appeared to be unchanged. However, when organic extractions are performed at pH conditions more moderate than those generally employed to isolate mutagens from foods, a 30-50% decrease in mutagenicity is observed.

Ammonia↗
PubMed1981

Serologic and parasitologic studies of Entamoeba histolytica in El Salvador, 1974-1978.

Serologic and parasitologic studies were done in El Salvador, C.A., from 1974-1978 to examine the reliability of the diagnosis of Entamoeba histolytica infection in an endemic area and to confirm the estimates of morbidity and mortality due to amebiasis. The results suggest that infection with E. histolytica is common, but the estimated prevalence is too high. Misdiagnosis occurring in hospital and public health laboratories was documented. Data collected from examining family members of persons with E. histolytica infection and disease indicate that most infections are asymptomatic, and support the hypothesis that estimates of morbidity and mortality rates are excessive.

Adolescent↗
PubMed1978

Influence of seminal additives and packaging systems on fertility of frozen bovine spermatozoa.

The following recommendations and conclusions are based upon results of fertility and laboratory studies, and general trends from field investigations. Fertility results due to the addition of enzymes have been variable and contradictory. Flushing of ampules with dry, gaseous nitrogen prior to filling has become a routine practice in processing semen to be frozen. For control of Vibrio fetus and Leptospira pomona, 2,000 micrograms of streptomycin and 1,000 u polymyxin B sulfate should be added per milliliter of raw semen immediately after collection. The extender for initial dilution should contain the same concentration of antibiotics used for raw semen plus 500 u penicillin. The glycerol portion of the extender should contain 500 u penicillin per milliliter. The effect of addition of sugars on fertility has been highly variable. The primary beneficial effect is probably due to their cryoprotective properties. A myriad of concoctions have been added to bovine semen and the results have been highly variable with respect to both motility and fertility. Results of subsequent experiments have rarely proven that addition of exotic compounds or mixtures has been of value. Higher mean fertility was obtained with semen in straws in 14 of 21 comparisons with ampules. The differences in favor of straws ranged from 1.1 to 18.9; while the range in favor of ampules was .1 to 4.4 percentage points. Fertility obtained with pellets has ranged from minus 12.8 to plus 11.9 percentage points in nonreturn rate (NR), compared to the corresponding NR with semen in ampules. Fertility of semen in ampules was higher in five of eight studies. Fertility of pelleted semen has ranged from minus 9.5 to plus 6.0 percentage points compared with straws. Fertility was higher for semen in pellets in only one of five investigations. Pellets should not be used until the potential for pathogenic contamination and exchange of spermatozoa among pellets is eliminated. There is a potential for higher fertility with semen in straws as compared to other packaging systems, but the issue of liquid nitrogen (LN) entry and possible contamination of semen should be further investigated. In general, fertility obtained with semen frozen in the .25 ml straw has been equal to or higher than semen in larger packages. However, they cannot be unequivocally recommended due to other considerations. From laboratory studies, it appears that greater spermatozoan survival is obtained when semen frozen in straws is thawed in water at 35 C or above.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1977

Purification and properties of the pyrrolidonecarboxylate peptidase of Streptococcus faecium.

Pyrrolidonecarboxylate peptidase (EC 3.4.11.8) from Streptococcus faecium was purified by fractionation with streptomycin sulphate and ammonium sulphate, by chromatography on Sephadex G200 and DEAE-cellulose, and by preparative electrophoresis on Sephadex G25. The purified enzyme on acrylamide gel showed a strong protein band which contained enzyme activity and a very faint band which had no activity. The subunit molecular weight of the purified enzyme was estimated by acrylamide gel electrophoresis in sodium dodecyl sulphate to be 42,000 +/- 1,000. The enzyme showed optimum activity at pH 7.6 and was unstable in the absence of 2-mercaptoethanol. The sensitivity of the enzyme to alkylating agents (N-ethylmaleimide and iodoacetamide) suggested that free sulphydryl groups were essential for enzyme activity. The enzyme was rapidly inactivated above 45 degrees C. The values of the Michaelis constants (Km) obtained with various L-pyrrolidonecarboxylyl dipeptides were similar although there was a 10-fold range in the maximal rates of hydrolysis of these substrates. Inhibition studies showed that the substrate analogues 2-pyrrolidone and pyrrolidonecarboxylate are competitive inhibitors of the enzyme. The binding of substrates and inhibitors to the active site of the enzyme is discussed.

Aminopeptidases↗
PubMed1977

Fibrin-bound tumour cells on a sclerosed mitral valve.

The association of fibrin and tumour cells on a sclerosed mitral valve in a 62-year-old woman is described. This was the first indication of malignant disease but bilateral ovarian cancer was proved two months later. ino further tumour deposits have been found in fifteen months. The tumour deposit on the valve was most likely a metastasis but primary heart valve sarcoma has not been positively excluded. If the lesion was a secondary deposit this has possible implications for the role of fibrin in metastasis in humans.

Female↗
PubMed1977

Secretory (juvenile) carcinoma of the breast.

A case of secretory (juvenile) carcinoma of the breast is reported in a 26-year-old multiparous woman who had been taking oral contraceptives for 7 months. The tumour recurred 8 months after local resection and axillary metastases were found at radical mastectomy. No further recurrence has been detected but the follow-up period is only 8 months. It is emphasized that secretory carcinoma of the breast originally described in children occurs also in adults. Early reports stressed the slow rate of growth, often with intervals of many years before recurrence, and the small risk of metastatic spread, many cases being cured by local resection. However, axillary metastases have been found in approximately 15% of the recorded cases. Consequently it is recommended that the initial treatment should be simple mastectomy with at least a low axillary resection.

Adult↗
PubMed1976

Autolysis of Streptococcus cremoris.

The autolysin of Streptococcus cremoris had the specificity of an endo-N-acetylmuramidase as it hydrolysed the linkage between N-acetylmuramic acid and N-acetylglucosamine. The enzyme had no amidase or endopeptidase action. It reached highest activity in the exponential phase of growth and in the electron microscope seemed to fragment the coccal wall at the equatorial ring.

Amidohydrolases↗