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Biomedical subjects

R Fox

Publications and source records attributed to R Fox.

At least 217 records · Page 12Linked to original sources
PubMed1990

Acute gastroenteritis in infants under 6 months old.

Sixty two babies under the age of 6 months who were admitted with gastroenteritis completed a study of gradual refeeding compared with abrupt refeeding after a period of rehydration. There was no difference in the incidence of recurrence of diarrhoea due to lactose intolerance, effect on weight, or duration of hospital stay. Twenty six babies (42%) had recurrence of diarrhoea after refeeding, all of whom settled with the introduction of a lactose free soya based formula. Well nourished babies under 6 months of age with mild to moderately severe gastroenteritis can be fed immediately with full strength milk feeds after rehydration. The introduction of a lactose free soya based preparation may provide an alternative to repeated attempts at regrading with cows' milk feeds in those patients with lactose intolerance.

Acute Disease↗
PubMed1990

Pathology of common bile duct stenosis in cystic fibrosis.

A case of cystic fibrosis complicated by common bile duct stenosis is described. Surgery successfully relieved the obstruction, but was complicated by Candida septicaemia. The previously unreported histological abnormalities of the common bile duct are discussed.

Adolescent↗
PubMed1990

Successful late treatment of venous air embolism with hyperbaric oxygen.

A case of haemodialysis-associated venous air embolism is described. The patient commenced hyperbaric oxygen therapy 21 hours after the event when, despite appearing decerebrate, he made a complete recovery. This case underlines the importance of all clinicians being aware of those centres with facilities for hyperbaric therapy and the need to refer all patients with cerebral air embolism even following a prolonged delay.

Embolism, Air↗
PubMed1990

Effects of hormonal status on bone density in adolescent girls.

Few data are available on bone density in late adolescence. We studied factors affecting peak bone density in females. Forty-three white girls, aged 13-20 yr, were studied. Integrated estrogen exposure over the pubertal years was obtained by a score based on physiological events known to reflect circulation estrogen levels. The subjects were selected to provide great variation in estrogen exposure. Bone mineral density (BMD) was measured by single photon absorptiometry (midradius) and dual photon absorptiometry (spine and first metatarsal of the foot). Weight, estrogen score, and testosterone levels were highly correlated with BMD of the spine, wrist, and foot (P less than 0.05). Age correlated positively only with the BMD of the wrist. Twenty-four girls reaching ages 18-20 yr in the 2 yr of observation were divided into groups reflecting low (less than 24), medium (25-48), and high (greater than or equal to 49) estrogen exposure. The lowest scoring groups had the lowest spine and wrist BMD (P less than 0.05). This group weighed less and had lower weight to height ratio (P less than 0.05), the lowest weight (P less than 0.05) during adolescence, the highest age of menarche, and the highest amount of fiber in the diet (P less than 0.05). These subjects were separated into low and high BMD groups. Those subjects with the lowest values for spine, wrist, and foot were found to have significantly lower estrogen exposure scores and lower weight/height ratios; in addition, low BMD of the foot was associated with higher activity levels. Thus, wrist and spine BMD are affected by estrogen exposure during adolescence and weight; foot BMD, in addition, was negatively affected by activity, suggesting that bone mass in the active adolescent is affected by the absence of estrogen exposure.

Absorptiometry, Photon↗
PubMed1990

HIV-1 infection: no evidence of cognitive decline during the asymptomatic stages. The Multicenter AIDS Cohort Study.

Cross-sectional studies have not adequately resolved the question of whether subjects infected with HIV-1 may suffer cognitive decline during the early, asymptomatic stages of the infection. We studied longitudinally 238 asymptomatic healthy HIV-1-infected homosexual/bisexual men (CDC groups 2 and 3) and 170 uninfected controls in the Multicenter AIDS Cohort Study with neuropsychological testing at semiannual intervals. A comparison of change in scores between visits 1 and 4 as well as a multivariate autoregressive analysis revealed no evidence of decline in test performance over time in the HIV-1-infected group compared with the seronegative controls. These findings suggest that a gradual cognitive decline does not occur during the early, asymptomatic stages of HIV infection.

Adult↗
PubMed1990

Mental retardation and perception of global motion.

We have found that mildly mentally retarded adults are impaired in their perception of global stereoscopic forms (Fox & Oross, 1988) in ways that cannot be attributed to peripheral visual deficits or failures to comprehend. To assess the generality of that result, we measured the ability of mentally retarded adults to perceive kinematographic forms. Mentally retarded and nonretarded adults were presented with a two-choice, forced-choice detection task requiring the location of a target's spatial position. The discriminability of the forms was varied by systematic reductions in both element density and temporal correlation. We found that, relative to nonretarded adults, mentally retarded adults exhibited large qualitative deficits in their ability to discriminate these kinematographic forms when either density or correlation was reduced. After considering a number of alternative interpretations of these data based on factors such as peripheral visual impairment and a failure to attend, we could find none more compelling than a perceptual interpretation, which posits a deficit within the short-range motion system.

Adult↗
PubMed1990

Temporal perturbations of binocular rivalry.

Successive durations of binocular rivalry are sequentially independent, random variables. To explore the underlying control process, we perturbed the cycle during a 30-sec viewing period by immediately forcing an eye to return to dominance whenever it became suppressed. During this period of forced dominance, that eye's individual dominance durations were unusually brief, but immediately following the period of forced dominance that eye's suppression durations were unusually long. However, no long-term change in the sequential pattern of rivalry occurred, and the stochastic independence of successive durations was maintained during and following the period of forced dominance. The same pattern of results was obtained with even longer periods of forced dominance. These results are consistent with the existence of a short-term adaptation, or fatigue, process responsible for transitions from dominance to suppression.

Adult↗
PubMed1990

HIV infection is not associated with Reiter's syndrome: data from the Johns Hopkins Multicenter AIDS Cohort Study.

Reiter's syndrome has been reported to occur in up to 10% of patients with HIV infection. However, no properly controlled epidemiological studies have been conducted to determine whether HIV infection is an independent risk factor or whether the immunodeficiency induced by HIV infection is permissive for infection with other arthritogenic organisms. The prevalence and incidence of Reiter's syndrome were determined in 1133 homosexual/bisexual men enrolled in the Johns Hopkins Multicenter AIDS Cohort Study. There was no difference in the prevalence of Reiter's syndrome at entry into the study in 1984 between 357 HIV-positive and 776 HIV-negative men: five per 1000 in both groups. During 5 years' follow-up, one case of Reiter's syndrome developed among each group of HIV-positive and HIV-negative men. These data fail to support a direct etiological role for HIV infection in the development of Reiter's syndrome.

Adolescent↗
PubMed1990

Incidence of Kaposi's sarcoma in a cohort of homosexual men infected with the human immunodeficiency virus type 1. The Multicenter AIDS Cohort Study Group.

Longitudinal data on 2,125 participants in the Multicenter AIDS Cohort Study (MACS) with documented antibodies to the human immunodeficiency virus type 1 (HIV-1) were used to examine the incidence of acquired immune deficiency syndrome (AIDS)-related Kaposi's sarcoma (KS) over time and to determine if sexual practices and hematologic variables prior to diagnosis differed for participants who develop KS vs. non-KS AIDS (NKS). In the first 4 years of the study, 84 seropositive men were observed to develop KS and 307 presented with an AIDS diagnosis other than KS. A systematic trend in the incidence of KS over time was not apparent in this population. The number of anal-receptive intercourse partners prior to diagnosis declined in a similar fashion for both AIDS groups. Although the number of partners with whom the men performed rimming decreased prior to diagnosis for both AIDS groups, a greater proportion of the KS AIDS group had performed this activity with multiple partners than had the non-KS AIDS group. Furthermore, history of oral gonorrhea was significantly (p = 0.027) more prevalent in the KS group. In addition, the KS AIDS group had lower cytomegalovirus antibody levels prior to diagnosis and higher levels of total immunoglobulin G. The groups did not differ with respect to baseline hematological measures, temporal trends in helper and suppressor T cells, or hepatitis B surface antigen or antibody. Given this profile of factors associated with the occurrence of KS, an infectious agent, in addition to HIV-1, is plausible as a proposed cofactor in the development of KS.

Acquired Immunodeficiency Syndrome↗
PubMed1989

The effect of smoking on theophylline kinetics in healthy and asthmatic elderly males.

The effect of smoking on theophylline kinetics was investigated in four groups of males over the age of 65 yr. The first group consisted of 14 healthy non-smoking males, the second group consisted of 8 healthy smoking males. The first and the second groups were administered a single oral dose of 300 mg tablet of sustained-release anhydrous theophylline product and serial blood samples were collected over 24 hr. The third group consisted of 22 clinically stable asthmatic non-smoking males, the fourth group consisted of 9 clinically stable asthmatic smoking males. The third and the fourth groups, were administered multiple oral doses equivalent to 300 mg of anhydrous theophylline from sustained-release Oxtriphylline every 12 hr for 72 hr; and blood samples were collected every two hours between 72-82 hrs. Serum theophylline concentrations were determined by HPLC. There were no significant differences between the smokers and non-smokers in observed maximum concentration (Cmax), its time (tmax), the area under the time-concentration curve (AUCo-t), and total body clearance rate (Cl). Aging appears to offset the known smoking inducing effect on the hepatic microsomal enzymes.

Aged↗
PubMed1989

Ocular manifestations of acquired immune deficiency syndrome.

The ocular complications of acquired immune deficiency syndrome (AIDS) include: (1) a noninfectious microangiopathy, most often seen in the retina, consisting of cotton-wool spots with or without intraretinal hemorrhages and other microvascular abnormalities; (2) opportunistic ocular infections, primarily cytomegalovirus (CMV) retinitis; (3) conjunctival, eyelid, or orbital involvement by those neoplasms seen in patients with AIDS (i.e., Kaposi's sarcoma and lymphoma); and (4) neuro-ophthalmic lesions. In a series of 200 AIDS patients evaluated clinically, AIDS retinopathy was present in 66.5%. Sixty-four percent had cotton-wool spots, and 12% had intraretinal hemorrhages. Cytomegalovirus retinitis was diagnosed in 28% of AIDS patients. Neuro-ophthalmic lesions were found in 8% of all AIDS patients and were present in 33% of those patients with cryptococcal meningitis. Acquired immune deficiency syndrome retinopathy was present in 40% of 35 patients with the AIDS-related complex (ARC) and in 1.3% of 232 patients with asymptomatic human immunodeficiency virus (HIV) infection, evaluated photographically. These results suggest that the prevalence of AIDS retinopathy increases with increasing severity of HIV infection, and that CMV retinitis presents a significant vision-threatening problem in AIDS patients.

Acquired Immunodeficiency Syndrome↗