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Biomedical subjects

A Lee

Publications and source records attributed to A Lee.

At least 721 records · Page 40Linked to original sources

Mobile elements bounded by C4A4 telomeric repeats in Oxytricha fallax.

A novel family of micronuclear elements termed telomere-bearing elements (TBEs) is described. All 1900 family members are eliminated during macronuclear development. We conclude that they are transposons, first because the members are moderately conserved in sequence and probably dispersed in the genome. Second, in two cases, sequence comparison of the termini and flanks of the element with the corresponding empty site indicate that elements cause 3 bp target duplications (AAT) upon insertion; the 3 bp are part of the 5 bp target sequence, AATGA. Lastly, both elements carry 77 or 78 bp inverted terminal repeats. The tip of each inverted terminal repeat is the 17 bp telomere-like sequence 5' C1A4C4A4C4. At least half of the elements have these 17 bp or an extremely similar sequence. One possible pathway for transposition into new micronuclear sites starts in the developing macronucleus with excision to create a free linear form to which telomeres are added, followed by a low frequency of movement to the micronucleus, and insertion into the germ-line micronuclear DNA.

Animals↗

Biotin deficiency and susceptibility to fatty liver and kidney syndrome in broiler chicks: reduced 6-phosphofructokinase (EC 2.7.1.11) activity but normal fructose 2,6-bisphosphate content in birds with hepatomegaly.

In two separate experiments, using different strains, broiler chicks were reared on either a commercial-type chick mash (control) or a fatty liver and kidney syndrome (FLKS)-inducing diet. In Expt a, chicks were killed on day 29 and in Expt b, on day 32. Body-weights and liver weights were measured, and values from those given the control ration used to construct a hepatomegaly index by employing a variant of linear discriminant analysis. Application of the index to FLKS birds revealed a statistically significant bimodal distribution of liver size. The birds with enlarged livers (high index) also possessed metabolic abnormalities in that 6-phosphofructokinase (EC 2.7.1.11; PFK-1) activity (measured at low substrate concentration) was depressed despite the presence of normal, or even slightly elevated fructose 2,6-bisphosphate concentration. This indicates the presence of an uncharacterized regulatory mechanism for PFK-1 in FLKS-susceptible birds.

Animals↗

Effect of phenolic compounds, ethyl alcohol, and sodium metabisulphite on the lytic activity of phage PL-1 on a Lactobacillus casei S strain.

The effect of phenolic compounds, ethyl alcohol, and sodium metabisulphite on the lytic activity of virulent bacteriophage PL-1 on a Lactobacillus casei S strain isolated from a lactic acid beverage fermentation was investigated. Catechin, caffeic, and gallic acids, commercially produced red, white, and champagne tannins, ethyl alcohol, and sodium metabisulphite inhibited plaque formation. Catechin, caffeic, and gallic acids were the most effective inhibitors of plaque formation. Commercially supplied oenocyanin was not effective.

Bacteriophages↗

Cefuroxime sodium.

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Bacterial Infections↗

Lipogenic enzyme activity and fructose 2,6-bisphosphate concentration in livers of two lines of domestic fowl (Gallus domesticus) selected for different body fat content.

Livers were obtained from two lines of domestic broiler which had been selected for low (lean) and high (fat) plasma very-low-density lipoprotein concentration over three generations. The fat line possessed significantly higher hepatic specific activities of malate dehydrogenase (NADP), ATP citrate lyase and fatty acid synthase, and lower glucose bisphosphatase than the lean line. The glycolytic enzymes, pyruvate kinase and phosphofructokinase, were similar and so was the concentration of fructose 2,6-bisphosphate. This recently discovered metabolic regulator was present at somewhat higher concentrations than previously reported in rats or mice. It exhibited a positive correlation with phosphofructokinase activity (only data for the fat line are shown), and stimulated enzyme activity when added to crude preparations.

ATP Citrate (pro-S)-Lyase↗

Sex differences in the metabolism of ethanol and acetaldehyde in normal subjects.

Blood ethanol and acetaldehyde concentrations were compared in normal young male and female subjects after intravenous infusion of 0.5 g of ethanol/kg body weight. After the infusion was completed, females had significantly higher mean concentrations of blood ethanol than males, but a significantly lower apparent volume of distribution (Vd) of ethanol (0.56 +/- 0.06 1/kg vs 0.68 +/- 0.17 1/kg, P less than 0.05). There were no differences in ethanol elimination rate (EER) (females 1.78 +/- 0.3 mmol h-1kg-1; males 1.87 +/- 0.41 mmol h-1kg-1). The mean value of the areas under the acetaldehyde/time curves (AUC) were significantly greater for males (88.5 +/- 26.4 mumol/1. h) than for females (58.6 +/- 31.5 mumol/1. h, P less than 0.05). Since the ethanol elimination rate was similar in both sexes, the observed differences in AUC for acetaldehyde may reflect the sex differences in metabolism of this substrate by the liver.

Acetaldehyde↗

Susceptibilities of 45 clinical isolates of Proteus penneri.

Patterns of susceptibility of 45 Proteus penneri clinical isolates to 14 antimicrobial agents were evaluated by a macrobroth dilution method. All strains were highly susceptible to ceftizoxime, ceftazidime, moxalactam, cefoxitin, gentamicin, tobramycin, netilmicin, and, with few exceptions, to amikacin, piperacillin, and cefoperazone. Most strains were susceptible to cefotaxime and ceftriaxone. All strains were resistant to cefazolin and cefsulodin.

Anti-Bacterial Agents↗

Proteus penneri and urinary calculi formation.

The clinical significance of Proteus penneri, a newly described species, is unknown. A case report is presented, which is to the best of our knowledge the first description of this organism causing a urinary tract infection and bladder calculi.

Aged↗

Temporal characteristics of cortisol metabolism in adrenalectomized primates.

The rhythmicities observed in the plasmatic levels of cortisol are generally attributed to rhythms of production and release of the hormone. Since the plasmatic concentration of any given substance is a function of its production and its removal from the circulation, it is conceivable that the metabolism of cortisol also occurs in an oscillating fashion. To test this hypothesis Rhesus monkeys were submitted to bilateral adrenalectomy; cortisol was replaced at a constant infusion rate while blood was sampled at hourly intervals for the measurement of cortisol plasma levels. Rhythmic oscillations in the cortisol levels were observed. These rhythms exhibited two major components: a circadian and an ultradian component. The authors suggest that these rhythms be considered whenever normal or pathologic hormone rhythmicities are analyzed.

Adrenalectomy↗

Targeted blood levels of cyclosporin for cardiac transplantation.

Forty-nine patients have undergone cardiac transplantation since July, 1982, and have been treated with maintenance cyclosporin and low-dose prednisone, 15 to 20 mg. Cyclosporin dose has been targeted to a whole-blood level of 1,000 ng/ml as measured by radioimmune assay. The actuarial survival rate in this group of patients has been 79% at 12 months and 71% at 21 months. Histologic rejection has occurred at all blood levels of cyclosporin, as has significant nephrotoxicity. The hepatic toxicity encountered has been more a clinical nuisance than significant problem. The administered dose of cyclosporin required to reach a target of 1,000 ng/ml has varied between 2 and 30 mg/kg/day. The average perioperative and late serum creatinine levels were 1.2 and 1.49 mg/dl and occurred with cyclosporin levels of 1,078 and 1,068 ng/ml, respectively. Late cyclosporin toxicity has persisted despite reduction in the dose of cyclosporin below the targeted 1,000 ng/ml. Some method of blood level monitoring is necessary in patients receiving cyclosporin immune suppression to assure adequacy of the administered dose. The 1,000 ng/ml target has provided adequate immune suppression. Significant nephrotoxicity has not correlated with the blood level measured.

Bilirubin↗

Shark cartilage contains inhibitors of tumor angiogenesis.

Shark cartilage contains a substance that strongly inhibits the growth of new blood vessels toward solid tumors, thereby restricting tumor growth. The abundance of this factor in shark cartilage, in contrast to cartilage from mammalian sources, may make sharks an ideal source of the inhibitor and may help to explain the rarity of neoplasms in these animals.

Animals↗

High-performance liquid chromatographic analysis of the new hypoxic cell radiosensitiser, Ro 03-8799, in biological samples.

A high-performance liquid chromatographic method of analysis with UV detection has been developed to measure levels of a new radiosensitiser, Ro 03-8799 and its N-oxide metabolite, in biological fluids and tissues. The accuracy and precision of the method have been determined in both plasma and urine, where the limits of quantitation are 100 and 500 ng/ml, respectively. Typical results are presented from a human volunteer study where samples were analysed by this method. Important aspects of the method, involving both sample handling techniques and chromatographic conditions are discussed.

Animals↗

Isolation and characterization of a spiral bacterium from the crypts of rodent gastrointestinal tracts.

Spiral-shaped bacteria with a distinctive morphology were isolated from the intestinal mucosa of rats and mice on a campylobacter selective medium using microaerophilic incubation. These bacteria have been shown by other authors to be present in the intestinal tracts of several animal species but have not been cultured previously. The results of electron microscopic examinations and biochemical testing have shown that these organisms do not correspond to any known genus. Colonization experiments with pure cultures in gnotobiotic rodents have shown these bacteria to be mucosa associated, with a particular affinity for intestinal crypts. The pattern of colonization of the intestinal crypts in gnotobiotes known to be free of other mucosa-associated organisms differed from the colonization occurring in conventional animals that possess a normal mucosa-associated flora.

Animals↗

Patterns of alcohol consumption and fetal development.

Effects of heavy, moderate, and rare alcohol consumption on fetal development were analyzed in a prospective study of 469 mother-infant pairs. Differential effects of heavy drinking in early and late gestation were evaluated by separate analysis of neonates born to women who reduced consumption before the third trimester. Using chi 2 analysis, multiple regression, and matched sets, statistically significant associations (P less than .01) were observed between sustained heavy drinking and both intrauterine growth retardation and congenital anomalies. These associations were independent of eight other risk factors. No differences were observed between offspring of rare and moderate drinkers. Infants born to women who reduced heavy drinking did not differ in growth from offspring of rare and moderate drinkers but demonstrated a higher frequency of abnormalities. Sustained heavy drinking represents a major risk; reduction in midpregnancy can benefit the newborn. Identification and therapy of heavy drinking are important components of prenatal care.

Abnormalities, Drug-Induced↗