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Biomedical subjects

M Lee

Publications and source records attributed to M Lee.

At least 1,099 records · Page 61Linked to original sources
PubMed1979

Effect of maternal ethanol administration on physical growth of the offspring in rats.

To study the effects of maternal alcohol consumption on the postnatal growth and physical development of the offspring, female Sprague-Dawley rats (200-220 g) were assigned to one of 3 groups. Group I (alcohol) received alcohol in drinking water (up to 20% v/v) for at least 4 weeks prior to mating, and 30% (v/v) throughout gestation. Purina Lab Chow was ad libitum. Group II (pair-fed) received the same amount of chow as was consumed by alcohol-fed animals, and an amount of corn starch calorically equivalent to the amount of alcohol consumed. Group III (ad libitum) were given chow and water ad libitum. Postnatally all animals were given chow and water ad libitum until day 51 post conception (PC). During pregnancy alcohol provided about 28% of the calories in group I, and the total calorie intakes of the alcohol and pair-fed groups were approximately 60% of that of the ad libitum controls. Weights at birth of offspring of pair-fed and ad libitum control mothers are not significantly different, but the offspring of animals given alcohol show a weight deficit of 28%, compared to the ad libitum controls. During the ensuing four weeks weight shows no indication of catching up to the controls. Total length shows the same pattern as body weight. Skeletal and muscle measurements are significantly less (p less than 0.01) in young of alcohol treated mothers than in those of the ad libitum control mothers. Skeletal maturity in the alcohol group lags behind (p less than 0.01) that of the pair-fed and ad libitum control groups and catch-up is not evident to day 51 PC. It is concluded that young born to animals given alcohol prior to and throughout gestation are physically and developmentally retarded and fail to catch up to the controls during the first four weeks after birth, although not exposed to alcohol postnatally.

Animals↗
PubMed1978

Nosocomial meningitis and bacteremia due to contaminated amphotericin B.

Nosocomial Gram-negative bacillary meningitis and bacteremia occurred in a patient who was receiving intrathecal and intravenous amphotericin B. An epidemiologic investigation found the amphotericin B to be contaminated with Enterobacter agglomerans, Pseudomonas fluorescens, and P aeruginosa. These contaminants were traced to a lot ot sodium phosphate buffer that was added to all intrathecal and intravenous amphotericin B preparations. The phosphate buffer underwent prolonged storage at room temperature and was not subject to terminal sterilization nor sterility testing. This parenteral admixture prepared in the hospital is now steam autoclaved and sterility tested before use.

Adult↗
PubMed1978

Nutritional status of a select group of free-living elderly people in Vancouver.

A study was conducted to determine the nutritional status of the free-living elderly population in Vancouver. The response rate of the sample was low. Dietary information from 104 single men and women and 23 couples was collected by the 24-hour recall method. Biochemical tests in 56 single individuals and 13 couples included measurement of hemoglobin concentration and hematocrit, plasma analysis for concentrations of total protein, iron, carotene, vitamin A, ascorbic acid, vitamin E and cholesterol and for transferrin saturation, and urine analysis for concentrations of creatinine, thiamin, riboflavin and N(1)-methylnicotinamide.Mean energy intakes were considerably below the Dietary Standard for Canada. However, mean intakes of individual nutrients were similar to or in excess of the Dietary Standard for Canada for single men and women and for married men. Married women had low average intakes of calcium, iron, thiamin and riboflavin but adequate intakes of other nutrients. Mean values for biochemical variables were within the accepted range as defined by the Interdepartmental Committee of Nutrition for National Defense in the United States. According to the Nutrition Canada definitions of "high risk" there were no individuals in high-risk categories for any biochemical variable except plasma cholesterol concentration and transferrin saturation. The dietary and biochemical data indicated that the nutritional status in this select group of elderly persons was good except for intake of total energy and, in married women, of calcium, iron, thiamin and riboflavin.

Aged↗
PubMed1978

Cytotoxicity of 5-fluoro-2'-deoxyuridine: requirement for reduced folate cofactors and antagonism by methotrexate.

Protein in vitro inhibition of thymidylate synthase (5,10-methylenetetrahydrofolate:dUMP C-methyltransferase, EC 2.1.1.45) by 5-fluoro-2'-deoxyuridylate requires 5,10-methylenetetrahydrofolate. The cytoxicity of 5-fluoro-2'-deoxyuridine towards cultured L1210 mouse leukemia cells is reduced when intracellular reduced folates are depleted, either by limiting the source in media or by inhibition of dihydrofolate reductase with methotrexate. Likewise, the intracellular amount of 5-fluoro-2'-deoxyuridylate covalently bound to thymidylate synthase in L1210 cells treated with 5-fluoro-2'-deoxyuridine is greatly diminished when cells are depleted of folate cofactors. The folate requirement for optimal growth of L1210 cells is lower than that required for maximal cytotoxicity of 5-fluoro-2'-deoxyuridine. These findings provide a biochemical rationale that may be useful in designing clinical protocols that use 5-fluorinated uracil analogs.

Animals↗
PubMed1978

Accommodation dynamics I. Range nonlinearity.

We show the presence of a new nonlinearity in accommodation dynamics. Positive accommodation is slower when the eye is operating in the near range; conversely, relaxation of accommodation is apparently slower during work in the far range. Latency of accommodation is unaffected by working range. This new dynamic range nonlinearity has been defined in connection with a continuing research study of accommodation responses in normal subjects and in clinic patients. Instrumentation and analysis procedures are described.

Accommodation, Ocular↗
PubMed1978

Median and ulnar nerve conduction determinations in the Erb's point--axilla segment in normal subjects.

Twenty-one median and 22 ulnar nerves were tested in 12 patients for motor nerve conduction velocity (MNCV) and motor nerve conduction time (MNCT) in the segments from Erb's point (N) to axilla (A) bilaterally. It was found that on this segment for both nerves, MNCV values equal to or smaller than 51 m/s or conduction times equal to or longer than 4 ms are to be considered abnormal. For comparative studies and for checking the normality of the tested nerves in their entire length, the more distally located segments in the same nerve were also tested. For diagnostic purposes, the differences between right and left MNCV or MNCT values determined in the same person on N-A segments of homologous nerves were analysed. Motor nerve conduction velocity or MNCT determinations on the N-A nerve segment are expected to replace MNCV determinations on the longer N-AE (AE=100 mm above elbow) nerve segment, which is now in use, for diagnosis of the thoracic outlet syndrome.

Adult↗
PubMed1978

Multicenter comparison of naproxen and indomethacin in rheumatoid arthritis.

In a double-blind, crossover study, naproxen, 250 mg twice a day, naproxen, 500 mg taken at bedtime, and indomethacin, 25 mg four times a day, were compared in 132 patients with rheumatoid arthritis; six centers participated in the study. Objective indices of arthritis activity, such as number of clinically active joints, walking time, and duration of morning stiffness, were nearly identical for the three treatment regimens. Of particular interest was the observation that efficacy of a single daily dose of naproxen was comparable to that of the twice-daily dosage. Naproxen was better tolerated than indomethacin, as shown by a statistically significant difference in the incidence of CNS complaints.

Adult↗
PubMed1978

Carbon dioxide effects on erythropoietin and erythropoiesis.

The addition of carbon dioxide during a short bout (6 to 24 hr) of hypoxia suppresses the production of Ep. The effects of carbon dioxide on Ep production and erythropoiesis were determined in hypoxic rats over a 6-day period. Carbon dioxide suppressed both renal and extrarenal Ep production induced by hypoxia. However, rats exposed to a hypoxic environment with 5% CO2 became as polycythemic as rats exposed to the same hypoxia without CO2. This may result from the following. (1) A factor other than Ep is involved in stimulating erythropoiesis in these animals. (2) The large amount of Ep produced during hypoxia is in excess, and only a small amount is needed to compensate for the hypoxia by producing increased numbers of RBCs. (3) A significant degree of hemoconcentration occured, resulting in the increased number of RBCs observed.

Animals↗
PubMed1977

Effects of membrane stabilizers on pancreatic amylase release.

Compounds with membrane stabilizing activity were studied as to their ability to affect pancreatic amylase release and the steps in the stimulus-secretion coupling process. Chlorpromazine, propranolol, and thymol were all found to inhibit bethanechol-stimulated amylase release and at slightly higher concentrations to induce release regardless of the presence of the secretagogue. This biphasic effect was similar to that found previously for the local anesthetic tetracaine. Release by high concentrations of propranolol and tetracaine was accompained by ultrastructural evidence of cell damage. Membrane stabilizers at concentrations which inhibited amylase release were shown to block bethanechol-induced depolarization and stimulation of 45Ca++ efflux although the drugs alone partially depolarized pancreatic cells. Release of amylase induced by Ca++ introduced by the ionophore A23187 was also abolished. The findings indicate that membrane stabilizers independently inhibit the steps leading to a rise in intracellular Ca++ and the subsequent Ca++-activated amylase release.

Amylases↗
PubMed1977

Neutral amino acid transport systems of tissue culture cells.

We have studied the interactions among a varied group of neutral amino acids for uptake into two different animal tissue culture cell lines. 3T3 mouse cells and Chinese hamster ovary cells were used in these studies. The results showed that the affinities of the amino acids clustered into two groups, one including amino acids such as glycine, alanine, and alpha-aminoisobutyric acid and the other group included amino acids such as leucine and phenylalanine. The specificities and properties of these systems are similar to those described earlier for the Ehrlich ascites cell, System A (alanine-preferring) and System L (leucine-preferring). System A is highly concentrative, sensitive to sodium ion, and serves only poorly for exchange while System L is not very concentrative or sensitive to alkali metal ion, although it serves very well for exchange with endogenous amino acids. The kinetic parameters for several amino acids are reported and other properties of the transport systems are discussed.

Alanine↗
PubMed1977

Regulation of amino acid transport activity and growth rate of animal cells in culture.

Balb/3T3 mouse cells grown in cell culture contain the A and L systems for neutral amino acid transport. L-Alanine was used as a test amino acid for the A system and L-leucine for the L system. Transport activities for both transport systems are altered as the growth conditions for the cells are altered. When cell growth was arrested by allowing cells to approach confluency, or by the removal of serum or by the addition of protein synthesis inhibitors, System A transport activity decreased and System L activity increased significantly. The content of the cellular amino acids increased 2- to 3-fold whenever cell growth was arrested by the conditions stated above. Increased cellular amino acids, therefore, are associated with decreased transport activity of System A and increased activity of System L. Altering cellular amino acids by loading or depleting the cells produced the predicted responses for the rapidly exchanging L-system but System A was less responsive. It is possible that regulatory mechanisms operate for the A system other than the direct action of alterations in cellular amino acid levels. The implications of the amino acid transport activity changes observed here on various studies on the role of transport in cell growth regulation and malignant transformation are discussed.

Alanine↗