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C J Mason

Publications and source records attributed to C J Mason.

13 recordsLinked to original sources
PubMed1996

Correlates of HIV-1 seropositivity among young men in Thailand.

Geographic and demographic correlates of risk for HIV-1 seropositivity were studied in 120,216 young men selected by lottery for service in the Royal Thai Army (RTA). The study population consisted of men selected between November 1991 and May 1993. Venous blood was collected at induction, and a brief demographic questionnaire was administered. HIV-1 seropositivity was established by Western blot confirmation of duplicate reactive ELISAs. Geographic variable provided the strongest correlate of risk, clearly distinguishing residents of the upper north, Bangkok, and the central region from the northeast. Overall 12.2% of men from the upper north were HIV-positive. Men who had lived in rural areas were at less risk in most regions of the country, but had equal risk in the upper north. Unmarried men and those with less education were at higher risk throughout the country. These data provide valuable information on the prevalence of HIV infection in one segment of the general population. Continued surveillance of this group will facilitate evaluation of Thailand's response to the epidemic.

Adult↗
PubMed1995

Declining prevalence of HIV-1 infection in young Thai men.

OBJECTIVE: To evaluate trends in HIV-1 seroprevalence in Thailand. DESIGN: HIV-1 serosurvey of successive cohorts of young Thai men entering service with the Royal Thai Army (RTA) between November 1989 and November 1994. METHODS: In November 1989, the RTA Medical Department began routine HIV-1-antibody screening of men who were selected by lottery for conscription. Between November 1989 and November 1994, 311,108 young men were screened at induction. Demographic data were collected between November 1991 and May 1993 and again in November 1994. RESULTS: The seroprevalence of HIV-1 among conscripts nationwide increased rapidly from 0.5% in 1989 to 3.5% in 1992 and reached 3.7% in 1993. In 1994, the overall prevalence decreased to 3.0%. The decrease was greatest in the upper North (from 12.4% in 1992 to 7.9% in 1994), where the prevalence has been the highest. However, decreases were observed in men from all regions of residence in the country, from both rural and urban areas, and at all educational levels. CONCLUSIONS: The decline in prevalence suggests declining incidence and that HIV control programs in Thailand are having an impact on the HIV epidemic.

Adult↗
PubMed1994

Evidence for a recent decrease in measles susceptibility among young American adults.

As part of an ongoing evaluation of US Army immunization policies, two serologic surveys were conducted at an army basic training center. Antibody status to measles, mumps, and rubella were determined by an ELISA in 969 soldiers in 1989 and 992 soldiers in 1990. Measles seronegativity rates, directly adjusted to the 15- to 24-year-old US population in 1980, decreased from 21.3% in 1989 to 12.5% in 1990 (P < .001). Decreases also were observed in mumps (16.2% to 14.7%) and rubella seronegativity rates (18.4% to 14.3%) from 1989 to 1990 but were not statistically significant. In subgroup analyses, significant decreases in measles seronegativity were observed in younger, white, male, and female cohorts. There is evidence that susceptibility among young adults had declined, although it remains unclear if this is due to increased immunization or exposure to natural disease.

Adolescent↗
PubMed1991

The susceptibility of young adult Americans to vaccine-preventable infections. A national serosurvey of US Army recruits.

OBJECTIVE: Due to recent resurgences of measles, mumps, and rubella among young US adults, we sought to generate antibody prevalence data for national and military immunization policy evaluations. DESIGN: We used a questionnaire and serological survey of Army recruits to assess antibody status to measles, mumps, rubella, and varicella by enzyme-linked immunosorbent assay and to poliovirus types 1, 2, and 3 by microneutralization assay. SETTING: Basic training reception centers at Fort Benning, Ga., and Fort Jackson, SC. PATIENTS: The study included 1547 US Army recruits who were inducted during September and October 1989. OUTCOME MEASURES: Seronegativity by various demographic factors. RESULTS: Seronegativity rates, directly adjusted to the 15- to 24-year-old US population in 1980, were 20.7% for measles, 15.6% for mumps, 17.5% for rubella, and 6.9% for varicella. For measles, mumps, and rubella, susceptibility was less in females, blacks, and college-educated recruits, and varicella susceptibility was greater in females and blacks. Recruitment who were born after 1969 lacked measles, mumps, and rubella antibodies more often than older recruits. The adjusted seronegativity rates for poliovirus types 1, 2, and 3 were 2.3%, 0.6%, and 14.6%, respectively; trends by age, sex, and race-ethnicity were generally unremarkable. CONCLUSIONS: Among young adult Americans, susceptibility to measles, mumps, and rubella is unevenly distributed and may be substantial. Our findings support national objectives to further improve immunization coverage in school-age and adult populations and provide further impetus for legislation requiring college entrants to present evidence of having received at least two doses of measles vaccine, with one on or after entry into elementary school.

Adult↗
PubMed1988

Oral nalbuphine for the treatment of pain after dental extractions.

A randomized, double-blind comparison of nalbuphine 30 mg or 60 mg by mouth and dihydrocodeine 30 mg by mouth was conducted in 75 patients with moderate to severe pain after surgery for dental extractions under general anaesthesia. A significant reduction in pain intensity followed each treatment and persisted throughout the 4-h observation period after nalbuphine, but only for 3 h after dihydrocodeine was given. Reduction in pain intensity was significantly greater 2, 3 and 4 h after the use of nalbuphine 60 mg than following dihydrocodeine 30 mg, and the mean total pain intensity difference was greater following nalbuphine 60 mg than following dihydrocodeine. Nalbuphine 60 mg effectively provided complete or good pain relief in more than 50% of the patients and only three patients in this group required additional analgesia during the period of observation, compared with nine patients in each of the other groups. However, the patients who received nalbuphine 30 mg had a significantly higher mean pain intensity before treatment than those in the other groups. The side-effects encountered were those typical of opioid medication; there were no statistically significant differences between the groups.

Administration, Oral↗
PubMed1986

Population dynamics in echinococcosis and cysticercosis: comparison of the response of Echinococcus granulosus, Taenia hydatigena and T. ovis to control.

A comparative study has been made of the progress in the control of ovine echinococcosis caused by Echinococcus granulosus and the ovine cysticercoses caused by Taenia hydatigena and T. ovis in New Zealand. The methods of control included an educational and a dog-dosing programme. In the Styx field trial, the Otago/Southland Surveillance Programme and the national control programme, E. granulosus declined towards extinction. In contrast, this same control effort transformed the cysticercoses from hyper-endemic to endemic status with focal epidemics. In this unstable state, the density-dependent constraint was negligible and superinfection occurred.

Animals↗
PubMed1986

Single breath end-tidal PCO2 measurement during high frequency jet ventilation in critical care patients.

The relationship between arterial and end-tidal carbon dioxide tensions following a single large breath was investigated in seven critically ill patients receiving high frequency jet ventilation. There was a close correlation (r = 0.989) between arterial and end-tidal carbon dioxide tensions over a wide range (3.29-8.95 kPa). Measurement of the end-tidal carbon dioxide tension following a single large breath may be useful in monitoring the efficiency of high frequency jet ventilation in the elimination of carbon dioxide.

Aged↗
PubMed1984

2-Acetylpyridine thiosemicarbazones. 10. 2-Propionyl-, 2-butyryl-, and 2-(2-methylpropionyl)pyridine thiosemicarbazones as potential antimalarial agents.

In view of the antimalarial properties observed for many 2-acetylpyridine thiosemicarbazones, a series of N4,N4-disubstituted thiosemicarbazones derived from 2-propionyl-, 2-butyryl-, and 2-(2-methylpropionyl)pyridine was prepared for evaluation against the malaria parasite, Plasmodium berghei, in the mouse. The thiosemicarbazones were made by the reaction of methyl hydrazinecarbodithioate with a 2-acylpyridine to give the intermediate methyl 3-[1-2-pyridinyl)alkylidene]hydrazinecarbodithioates. Reaction of the latter with 3-azabicyclo[3.2.2]nonane, 1-(2-pyridinyl)piperazine, or 1H-hexahydroazepine gave the requisite thiosemicarbazones. The three thiosemicarbazones derived from 3-azabicyclo[3.2.2]nonane were most effective, the greatest potency being exhibited by 3-azabicyclo-[3.2.2]nonane-3-thiocarboxylic acid 2-[1-(2-pyridinyl)butylidene]hydrazide (4) which cured 4/5 mice at a dose of 160 mg/kg. In contrast to the related thiosemicarbazones derived from 2-acetylpyridine, virtually no toxic effects were observed in the series described here.

Animals↗
PubMed1983

2-Acetylpyridine thiosemicarbazones. 6.2-Acetylpyridine and 2-butyrylpyridine thiosemicarbazones as antileukemic agents.

N4-Monosubstituted and N4,N4-disubstituted thiosemicarbazones derived from 2-acetylpyridine, 2-acetyl-6-methylpyridine and 2-butyrylpyridine, and N4,N4-disubstituted selenosemicarbazones derived from 2-acetylpyridine were evaluated against leukemia P388 in the mouse. Significant antitumor activity (T/C greater than 125%) was observed for members of each class. Enhancement of antitumor activity resulted from increasing the size of the N4-substituent of the thiosemicarbazone moiety. Selenosemicarbazones were less active than the corresponding thiosemicarbazones.

Animals↗
PubMed1979

2-Acetylpyridine thiosemicarbazones. 1. A new class of potential antimalarial agents.

Based on the antimalarial properties observed for 2-acetylpyridine 4-phenyl-3-thiosemicarbazone (1), an extensive series of related thiosemicarbazones was prepared and tested against Plasmodium berghei in mice. Screening results indicated that the presence of the 2-pyridylethylidene group was critical and that certain phenyl, benzyl, phenethyl, or cycloalkyl groups at N4 of the thiosemicarbazone moiety also contribute to antimalarial activity.

Animals↗
PubMed1979

2-Acetylpyridine thiosemicarbazones. 2. N4,N4-Disubstituted derivatives as potential antimalarial agents.

The most effective antimalarial agents among the N4-monosubstituted 2-acetylpyridine thiosemicarbazones recently described by us have a cyclohexyl or a phenyl substituent and produce cures in Plasmodium berghei infected mice at a dose of 160 and 320 mg/kg, respectively. We report here on a related series of N4,N4-disubstituted 2-acetylpyridine thiosemicarbazones. Several members of this group bearing alkyl or cycloalkyl substituents at N4 show activity superior to the most active monosubstituted 2-acetylpyridine thiosemicarbazones. However, the greatest improvement in potency was seen when the N4-nitrogen atom was incorporated into a six- or seven-membered ring, such as the piperidine, piperazine, or azabicyclo[3.2.2]nonane systems, to give compounds with curative properties at a dose level as low as 20 mg/kg.

Animals↗