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Biomedical subjects

T J Tucker

Publications and source records attributed to T J Tucker.

13 recordsLinked to original sources
PubMed1996

Hepatitis E in South Africa: evidence for sporadic spread and increased seroprevalence in rural areas.

Hepatitis E virus (HEV) is a major cause of non-A, non-B hepatitis in developing countries. Factors influencing sporadic spread of hepatitis E are unclear. We examined anti-HEV seroprevalence and demographic data from 407 urban and 360 rural black South African adults living in formal housing, squatter camps, or mud huts. Anti-HEV sero-prevalence ranged from 5.8% to 19.1% (mean 10.7%) in the different regions. Mean urban and rural rates were 6.6% and 15.3%, respectively (P = 0.0001). Rural mud hut dwellers, using unchlorinated river water, were at greater risk (17.4%) than rural villagers (5.3%; P = 0.008). A linear relation was found between seroprevalence and age, suggesting sporadic spread. The high prevalence in mud hut dwellers suggests that contaminated water plays a major role in HEV spread in South Africa. Routine chlorination or boiling of river drinking water before consumption may reduce HEV infection.

Adult↗
PubMed1994

Synthesis of a series of 4-(arylethynyl)-6-chloro-4-cyclopropyl-3,4-dihydroquinazolin-2(1H)-ones as novel non-nucleoside HIV-1 reverse transcriptase inhibitors.

As part of an ongoing effort to prepare novel non-nucleoside inhibitors of human immunodeficiency virus type-1 (HIV-1) reverse transcriptase (RT), a series of 4-(arylethynyl)-6-chloro-4-cyclopropyl-3,4-dihydroquinazolin -2(1H)-ones 4aa-l has been prepared. Target compounds 4a-e were synthesized via addition of various 1-lithio-2-(aryl)alkyne nucleophiles to a 1-protected-4-cyclopropylquinazolin-2(1H)-one (7), followed by deprotection. The 3-methyl compound 4aa was prepared in an analogous manner, with the 3-alkylation performed prior to deprotection. Alternatively, the target compounds 4f-l were prepared by addition of 1-lithio-2-(trimethylsilyl)acetylene to 7, followed by deprotection and subsequent palladium-catalyzed coupling with various aryl halides. By incorporating an aryl group onto the end of the 4-acetylene functionality, the requirement for a metabolically labile 3-methyl group on the dihydroquinazolinone nucleus has been eliminated. A number of the target compounds were shown to be potent inhibitors of HIV-1 RT. Compound 4a, which had exhibited the most favorable overall biological profile, was resolved via a four-step procedure to provide the enantiomers 13a and 13b. Compound 13a having the (-)-4(S) configuration was shown to be the active enantiomer and was selected as a candidate for further investigation.

Cells, Cultured↗
PubMed1994

Hepatitis E.

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Female↗
PubMed1992

A series of potent HIV-1 protease inhibitors containing a hydroxyethyl secondary amine transition state isostere: synthesis, enzyme inhibition, and antiviral activity.

A series of HIV-1 protease inhibitors containing a novel hydroxyethyl secondary amine transition state isostere has been synthesized. The compounds exhibit a strong preference for the (R) stereochemistry at the transition state hydroxyl group. Molecular modeling studies with the prototype compound 11 have provided important insights into the structural requirements for good inhibitor-active site binding interaction. N-Terminal extension of 11 into the P2-P3 region led to the discovery of 19, the most potent enzyme inhibitor in the series (IC50 = 5.4 nM). 19 was shown to have potent antiviral activity in cultured MT-4 human T-lymphoid cells. Comparison of analogs of 19 with analogs of 1 (Ro31-8959) demonstrates that considerably different structure-activity relationships exist between these two subclasses of hydroxyethylamine HIV-protease inhibitors.

Amino Acid Sequence↗
PubMed1992

Synthesis and antiviral activity of a series of HIV-1 protease inhibitors with functionality tethered to the P1 or P1' phenyl substituents: X-ray crystal structure assisted design.

By tethering of a polar hydrophilic group to the P1 or P1' substituent of a Phe-based hydroxyethylene isostere, the antiviral potency of a series of HIV protease inhibitors was improved. The optimum enhancement of anti-HIV activity was observed with the 4-morpholinylethoxy substituent. The substituent effect is consistent with a model derived from inhibitor docked in the crystal structure of the native enzyme. An X-ray crystal structure of the inhibited enzyme determined to 2.25 A verifies the modeling predictions.

Binding Sites↗
PubMed1988

Antigenic analysis of a major neutralization site of herpes simplex virus glycoprotein D, using deletion mutants and monoclonal antibody-resistant mutants.

Herpes simplex virus glycoprotein D is a component of the virion envelope and appears to be involved in attachment, penetration, and cell fusion. Monoclonal antibodies against this protein can be arranged in groups on the basis of a number of biological and biochemical properties. Group I antibodies are type common, have high complement-independent neutralization titers, and recognize discontinuous (conformational) epitopes; they are currently being used in several laboratories to study the functions of glycoprotein D. We have used a panel of neutralization-resistant mutants to examine the relationships between these antibodies in detail. We found that they can be divided into two subgroups, Ia and Ib, such that mutations selected with Ia antibodies have little or no effect on binding and neutralization by Ib antibodies and vice versa. In addition, Ia antibodies are able to bind deletion and truncation mutants of glycoprotein D that Ib antibodies do not recognize, suggesting that their epitopes are physically distinct. However, with one exception, Ia and Ib antibodies block each other strongly in binding assays with purified glycoprotein D, whereas antibodies from other groups have no effect. We have therefore defined the sum of the Ia and Ib epitopes as antigenic site 1.

Antibodies, Monoclonal↗
PubMed1987

Vitamin and proximate composition of fast-food fried chicken.

As part of the USDA's effort to obtain accurate data for nutrient composition handbooks, we determined proximate composition and vitamin (thiamin, riboflavin, niacin, folacin, pantothenic acid, and vitamins B-6 and B-12) content of fast-food fried chicken. Ninety-four samples were purchased from six chains in 10 cities throughout the United States. Vitamin content of breast and thigh meat portions differed, and slight differences in composition among brands were noted. Thiamin values for breast and thigh muscle, respectively, ranged from 0.062 to 0.136 and from 0.078 to 0.122 mg/100 gm; riboflavin, from 0.176 to 0.205 and 0.249 to 0.328 mg/100 gm; niacin, from 6.32 to 8.46 and 3.86 to 5.57 mg/100 gm; vitamin B-6, from 0.315 to 0.390 and 0.189 to 0.271 mg/100 gm; folacin, from 4.2 to 6.9 and 5.00 to 8.00 micrograms/100 gm; vitamin B-12, from 0.331 to 0.459 and 0.382 to 0.596 micrograms/100 gm; and pantothenic acid, from 1.48 to 1.68 and 1.58 to 1.77 mg/100 gm. Pressure-fried samples tended to have higher percentage moisture and lower percentage fat than crispy, open-vat fried samples. Fat ranged from about 15% to 20%.

Animals↗
PubMed1985

Gastric emptying in exercised mice.

Male adult mice were fasted for 8-10 hr, given a 1% phenol red marker solution, and exercised on a treadmill. Mice exercised at 0.50 mph had significantly faster gastric emptying rates after 15 min of exercise than non-exercised mice; however differences were not significant for longer periods of time. Mice exercised at 0.25 mph did not have significantly different gastric emptying rates at any time interval studied. Larger volumes empty faster than smaller volumes from stomachs of exercised mice.

Animals↗