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Biomedical subjects

T Jackson

Publications and source records attributed to T Jackson.

At least 127 records · Page 7Linked to original sources
PubMed1989

The efficacy of L-tryptophan in the reduction of sleep disturbance and depressive state in alcoholic patients.

Alcoholic male inpatients (N = 76) served as subjects in this study which examined the effect of L-tryptophan on depressive state and sleep disturbance. All subjects were residents of a 6-week alcohol treatment program at a Veterans Administration Medical Center. Subjects' degree of depression (Zung's Depression Scale) and sleep satisfaction (Webb's Post-Sleep Inventory) were measured four times during the study, just prior to and following ingestion of a substance that was either 3 gms L-tryptophan or 3 gms of an identical-appearing placebo. Subjects in the L-tryptophan/placebo condition received the active substance for 4 days followed by the placebo with a 4-day washout period in between. A second group of subjects received the same regimen of reverse order and a third received placebos on both occasions. There were two additional control groups that received no substances. All subjects in the study reported decreased levels of depression due to nonspecific treatment effects. The subjects who took L-tryptophan in either sequence reported even lower levels of depression. Sleep disturbance was not affected by L-tryptophan since it was barely present when the study began. A phenomenon referred to as the interval effect is discussed and an alternative explanation for this effect is offered.

Adult↗
PubMed1989

Reversal of galactosemic-induced inhibition of PGH synthase activity in cultured lens epithelial cells.

Inhibition of prostaglandin synthesis as determined by prostaglandin endoperoxide synthetase (PGH synthase) activity is associated with polyol accumulation in cultured bovine lens epithelial cells (BLECs) incubated six days in minimal essential medium (MEM) containing 40 mM galactose (Gal). In order to better understand the nature of the correlation between hypergalactosemic exposure, polyol accumulation and inhibition of prostaglandin synthesis, a series of culture media reversal and sorbinil (an aldose reductase inhibitor) addition studies were carried out. BLECs were incubated in Gal for six days, then changed to galactose-free MEM +/- sorbinil for a three day recovery period. PGH synthase activity reduced to 66% of control after six days of exposure to Gal. The simultaneous administration of sorbinil during a nine day Gal incubation significantly protected the enzymatic activity, while the activity of PGH synthase further declined to 41% of control under the same conditions in the absence of sorbinil. Within 72 hours of media reversal, PGH synthase activity equaled or exceeded control values in BLECs switched to either MEM or MEM + sorbinil. Indeed, an enhanced prostaglandin biosynthetic capacity as demonstrated by radioimmunoassay was exhibited with microsomes prepared from cells switched from Gal into Gal-free MEM +/- sorbinil, corroborating the beneficial effect of media reversal. Furthermore, following 72 hours of reversal, the cellular dulcitol level was 93 nmol/micrograms PO4 for BLECs switched to MEM alone; no detectable level of polyol was observed in BLECs changed to MEM + sorbinil. In contrast, the polyol content in BLECs after six days of exposure to Gal was 185 nmol/micrograms PO4 and increased to 334 nmol/micrograms PO4 after nine days of continuous incubation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Sorbinil prevents the galactose-induced inhibition of prostaglandin synthesis in lens cells.

The relationship between microsomal prostaglandin biosynthesis, PGH synthase activity and cell morphology was investigated with cultured bovine lens epithelial cells under physiological and hypergalactosemic conditions. The rate of lens cell microsomal PGE2 generation fell from 5.3 to 2.2 pg micrograms protein-1 min-1; PGF2 alpha declined from 7.7 to 4.8 pg micrograms protein-1 min-1 within 20 hr of exposure to 40 mM galactose. The decreased PGE2 and PGF2 alpha biosynthetic capability was attributed to a reduction in PGH synthase activity which reduced to 62% of control (5.5 mM glucose) after a 20 hr exposure to galactose. Measurement of PGH synthase activity after 6 days of continuous exposure to galactose resulted in a further reduction to 55% of control. The diminution in microsomal prostagladin biosynthesis and decline in PGH synthase activity precluded ultrastructural alterations, such as large vacuole formation and severe autodegradation of organelles. The simultaneous introduction of sorbinil, an aldose reductase inhibitor, to the galactose medium not only prevented the decrease in microsomal prostaglandin biosynthesis and PGH synthase activity, but also the detrimental morphological complications. The lens epithelial cell system may provide a useful model for examining the biochemical and morphological-related consequences of sustained hypergalactosemia and their potential regulation by aldose reductase inhibitors.

Animals↗
PubMed1987

Cellular immune competence and diarrheal morbidity in malnourished Bangladeshi children: a prospective field study.

A year-long prospective study of 152 Bangladeshi children with mild to moderate protein-calorie malnutrition related nutritional status and cellular immune defects to morbidity due to diarrheal, respiratory, and febrile diseases. In children older than 36 mo, wasting correlated with skin test anergy to three recall antigens and with inability to initiate hypersensitivity to dinitrochlorobenzene. In this older age group, anergy was associated with a 58% increased attack rate and an 83% increased duration of diarrheal diseases but not with febrile or respiratory infections. In stepwise regression analysis, this anergy effect was independent of the small negative impact of poorer nutritional status on morbidity. Ninety-three percent of diarrheal illnesses lasting at least 14 d were among anergic children. Cellular immune incompetence, indicated by anergy of unknown etiology, is associated with increased diarrheal morbidity and may promote the vicious cycle of repeated infections and deteriorating nutritional status.

Bangladesh↗
PubMed1985

Evaluation of Gonodecten for the presumptive diagnosis of gonococcal urethritis in men.

Gonodecten (Gd; U.S. Packaging Corp., LaPorte, Ind.) is a commercially available test for the presumptive diagnosis of gonococcal urethritis in men. With this test, urethral discharge is collected on a swab, placed in a plastic tube, and moistened with oxidase reagent. Development of a purple color on the swab within 3 min indicates the presence of gonococci. This system was compared with culture and Gram-stained smear for the diagnosis of gonorrhea. Of 240 specimens tested, 174 were positive with culture, Gram stain, and the Gd test and 48 were negative with all tests. For eight specimens, cultures and smears were positive, but the Gd test was negative. Nine specimens produced positive Gd tests with negative smears and cultures. Only one specimen was positive on culture and with the Gd test and negative on Gram-stained smear. Haemophilus species were isolated from 14 specimens; 5 produced positive Gd test reactions, with gonococci being coisolated from 4. The sensitivity and specificity of the Gd test compared with culture were 95.6 and 84.2%, respectively, whereas the Gram stain was 99.5% sensitive and 100% specific compared with culture. The Gd test may be a useful screening test for the diagnosis of gonorrhea in men with urethral discharge, particularly in settings where a microscope, Gram stain reagents, or technological expertise is not readily available.

False Negative Reactions↗
PubMed1980

Safety effectiveness of pesticide mixing-loading and application equipment used in 1976.

The effectiveness of currently used pesticide mixing-loading and application equipment in preventing workers from being exposed to cholinesterase (ChE) inhibiting pesticides was measured. Blood samples from workers involved in the application of pesticides in Monterey and Imperial counties of California were analyzed for ChE activity. The analyses indicated that only the mean red cell activity of mixer-loaders was significantly less than controls. Seasonal variations in ChE activity were noted for workers in Imperial County between January and August. These variations were apparently related to the toxicity of the pesticides used. A prototype, closed-transfer system used in Imperial County did not substantially reduce pesticide residues in the air around mixing-loading sites or prevent a reduction in ChE activity over that of open-transfer systems. This was attributed to inadequate training in the use of the new equipment on the part of the mixer-loaders and improperly maintained equipment. A protytype closed-transfer system used in Monterey County appeared to give some protection to mixer-loader applicators during the application season; however, the blood ChE activities of two mixer-loaders using another prototype closed system in Monterey County were severely depressed.

Agricultural Workers' Diseases↗
PubMed1980

Safety effectiveness of closed-transfer, mixing-loading, and application equipment in preventing exposure to pesticides.

Blood cholinesterase (CHE) activities and urinary dialkyl phosphate levels of five mixer-loaders and four mixer-loader applicators, using a closed-transfer system in conjunction with mixing-loading and application equipment, were monitored over a period of 18 weeks. Airborne pesticide residues in the breathing zone during mixing-loading and the transfer of concentrated liquid pesticide from their original container to mix and spray tanks were determined along with airborne residues during ground application. Blood ChE activities of the majority of the workers increased slightly during the study with increased use of toxic organophosphates and carbamates. Urinary dialkyl phosphate levels varied between 0.02 and 2.4 ppm. During the study, the blood ChE activities of two mixer-loaders decreased and dialkyl phosphate levels of 2.4 ppm were found in the urine of one worker. An investigation indicated that the workers had failed to use the provided closed-transfer system. Airborne residues from liquid pesticides during closed transfer and mixing-loading averaged 5.8 microgram/m3, while residues from dusty powders averaged 152 microgram/m3. Airborne residues during ground application averaged 3.7 microgram/m3 during the workday. Mevinphos residues on cloth patches averaged 0.2 microgram/cm2.

Agricultural Workers' Diseases↗