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Biomedical subjects

C C Lo

Publications and source records attributed to C C Lo.

25 records · Page 2Linked to original sources
PubMed1995

The effects of internal and external control factors on college students' marijuana use and cessation of use.

The purpose of this study was to examine how selected internal and external control variables influence lifetime use, frequency of use, and cessation of use of marijuana. The internal control factor, comprising the variables 1) perceived risk of marijuana use and 2) attitudes toward prohibition of marijuana use, refers to a built-in personal tendency toward conventionality. The external control factor refers to social-environmental forces which discourage marijuana use. External control is indicated by factors including the number of extra-curricular activities in which an individual is involved; place of residence; the availability of marijuana; peer attitudes toward marijuana use; the number of an individual's friends who use marijuana; and the number of occasions on which an individual has observed others using marijuana. The study's results show that both internal and external control factors are significant predictors of the frequency of marijuana use. The external control factor, however, plays a more important role in explaining lifetime marijuana use and cessation of marijuana use.

Health Behavior↗
PubMed1995

The facilitating and enhancing roles Greek associations play in college drinking.

A quasi-longitudinal, retrospective survey was used to examine the relationship of Greek affiliation and intensity of drinking in college. Explanations of higher levels of drinking among Greeks usually revolve around subcultural support, differential association, and reference group behavior. That is, association with pro-drinking students in a drinking subculture increases the members' drinking level. In this study, students' high-schooling drinking patterns were used to partially explain the decision to join Greek groups in order to continue prior drinking habits. Greek affiliation was found to serve as both a facilitating and enhancing factor in collegiate alcohol use.

Adolescent↗
PubMed1987

Observations on predicted brain influx rates of neurotransmitter precursors. Effects of tumor, operative stress with tumor removal, and postoperative TPN of varying amino acid compositions.

Effects of tumor, operative stress and tumor removal, and postoperative TPN of varying amino acid compositions on brain levels of tryptophan or tyrosine as predicted by their brain influx rates were studied in normals and in malnourished cancer patients. Concentrations of the large neutral amino acids (LNAA) were determined in patients before and after tumor removal, and in postoperative patients before and after receiving either a standard TPN solution (STD-TPN), or a branched-chain amino acid solution (BCAA-TPN). The LNAA were altered in all groups versus normals. Brain influx rates showed the following: in preoperative patients, predicted brain tryptophan levels were below normal (P less than 0.001), whereas tyrosine levels were within or above normal; no significant differences between pre- and postoperative tryptophan or tyrosine levels; postoperative STD-TPN did not change predicted brain tryptophan concentration from preinfusion values, but BCAA-TPN decreased it (P less than 0.001), underscoring the common transport carrier; and preinfusion predicted brain tyrosine levels were decreased (P less than 0.001) by both types of TPN solutions. These results imply low substrate levels for brain serotonin and catecholamine synthesis, possibly affecting functions dependent on their control.

Amino Acids↗
PubMed1975

Protein requirements of men in a hot climate: decreased urinary nitrogen losses concomitant with increased sweat nitrogen losses during exposure to high environmental temperature.

In two separate experiments 8 healthy young men were given an egg-milk formula at a level of 0.7 g protein/kg per day, and were exposed to high environmental temperature (34--37 C, 7 hours daily) or cool temperature (21--26 C, all day), alternately. In the first experiment a 16-day hot period was followed by a 20-day cool period and finally by a 20-day hot period. Daily urinary nitrogen (N) loss of the last 8 days of cool period, 82.2 mg/kg, was significantly higher than that of the last 8 days of the 20-day hot period 69.7 mg/kg. Daily skin N loss was significantly lower during the last 8 days of the cool period (3.5 mg/kg) than during the last 8 days of the 20-day hot period (11.9 mg/kg). Urinary N and skin N lossess were negatively correlated (r equal to -0.905) in these periods. In the second experiment a 28 day hot period was followed by a 20-day cool period. Skin N loss diminished from 12.3 mg/kg daily during the last 12 days of the 28-day hot period to 4.1 mg/kg during the last 12-days of the cool period. At the same time, urinary N loss increased significantly from 81.4 mg/kg during the 28-day hot period to 95.2 mg/kg during a cool period. Urinary N and skin N losses were again negatively correlated (r equal to -0.620) during these periods. Results of these studies indicate that when skin N loss increases during high temperature, urinary N loss decreases gradually, but total N loss does not increase.

Adult↗