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Biomedical subjects

R Fox

Publications and source records attributed to R Fox.

At least 253 records · Page 14Linked to original sources
PubMed1987

Clinical manifestations of acute infection with human immunodeficiency virus in a cohort of gay men.

During a prospective study of the natural history of human immunodeficiency virus (HIV) infection in a cohort of gay/bisexual men, information on self-reported symptoms lasting for 3 or more days during the previous 6 months was collected without knowledge of the subject's HIV serological status. Twenty-two people were retrospectively found to have seroconverted to HIV during the interval. Each seroconverter was matched to two seronegative and two seropositive controls. Matched case-control analyses using the seronegative controls determined that the following symptoms lasting for 3 or more days were associated with new HIV infection: fever greater than 37.7 degrees C, swollen lymph nodes, night sweats and headaches. Matched case-control analyses using the seropositive controls determined that the following symptoms lasting for 3 or more days were associated with new HIV infection: fatigue, fever greater than 37.7 degrees C, swollen lymph nodes, night sweats and headaches. It was notable that the majority of seroconversions were not associated with any symptoms lasting for 3 or more days. Due to their non-specificity, symptoms associated with seroconversion are not likely to have a high positive predictive value. In high risk populations, however, appearance of these symptoms may facilitate identification of early infection that may be important for studies of natural history or for optimal timing for initiating antiviral therapy.

Fatigue↗
PubMed1987

Effect of HIV antibody disclosure on subsequent sexual activity in homosexual men.

During a prospective study of the natural history of AIDS, 1001 homosexual or bisexual men were offered the opportunity to learn their HIV antibody status. Six hundred and seventy (67%) of the population who elected to do so were similar to the 331 (33%) people who declined in a number of baseline characteristics. All were counselled to practice safe sex. To determine whether disclosure of HIV serologic status affects subsequent sexual behavior, we examined changes at four time-points in three sexual activities during the previous 6 months: the number of male partners with whom the participant had (1) sexual intercourse, (2) unprotected anal receptive intercourse, and (3) unprotected anal insertive intercourse. All activities decreased strikingly over the 18-month study period. Following disclosure, the mean number of partners dropped to 47% of the baseline number in people remaining unaware of their antibody status, to 45% in people told that they were seropositive, and to 55% in people told that they were seronegative. The mean number of partners for younger seropositives declined less than that for older seropositives. The mean number of partners with whom unprotected anal receptive intercourse was practiced declined to 57% of baseline in unaware people, 42% in aware seropositives, and 62% in aware seronegatives. The mean number of partners with whom unprotected anal insertive intercourse was practiced declined to 52% of baseline in unaware people, 42% in aware seropositives and 59% in aware seronegatives. Disclosure of a negative test result led to a significantly smaller decline in these sexual activities.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1986

Phase I and pharmacokinetic study of tiazofurin (NSC 286193) administered by 5-day continuous infusion.

A phase I and pharmacokinetic study of tiazofurin (NSC 286193), a C-nucleoside that inhibits IMP dehydrogenase, has been completed. The drug was administered by continuous infusion over 5 days. The maximum tolerated dose was 1650 mg/m2 per day, neurological toxicity being the dose-limiting factor. Gastrointestinal and hematological toxicity were mild. A definite relationship exists between dosage and steady-state levels. The plasma clearance was 29.13 (+/- SD 4.05) ml/min per m2. No complete or partial remissions were demonstrated among the 18 patients treated at five dose levels between 550 mg/m2 and 2200 mg/m2 per day.

Adult↗
PubMed1986

Spatial resolution of the Galago.

The spatial vision of two adult galagos (Galago crassicaudatus) was assessed using a two choice discrimination task to determine their contrast sensitivity. Both contrast sensitivity functions exhibited low and high spatial frequency attenuation with the peak sensitivity at 1%. For one animal, the peak occurred at 0.5 c/deg and the extrapolated cutoff frequency was 2.6 c/deg; for the other, the peak was 1 c/deg and the cutoff was 4.3 c/deg. For this animal, grating acuity was also tested and, depending upon definition of threshold, yielded threshold estimates from 4.8 to 6.0 c/deg. The data supports the conclusion that the spatial vision of the galago and the cat is quite similar, a congruence that presumably reflects their adaptation to a nocturnal niche, rather than their divergent phylogenetic origins.

Animals↗
PubMed1986

Carcinoma of the nasopharynx and posterior pharyngeal wall.

The overall prognosis for carcinoma of the nasopharynx and posterior pharyngeal wall continues to be dismal. Gloomy statistics persist despite a wide variety of protocols involving irradiation, chemotherapy, and surgery. The single solid advance in treatment of these malignancies has come with the evolution of the myocutaneous flap, which is discussed in this article.

Carcinoma, Squamous Cell↗
PubMed1986

Endotoxemia causes increased lung tissue lipid peroxidation in unanesthetized sheep.

Our purpose was to determine whether lipid peroxidation of lung tissue, a reflection of O2 radical injury, occurs with endotoxin, and whether the degree of tissue change corresponds with the degree of increased protein permeability. Unanesthetized adult sheep with lung lymph fistulas were given Escherichia coli endotoxin at a dose of 2 micrograms/kg (n = 34). Tissue lipid peroxidation was measured using the thiobarbituric acid assay for malondialdehyde (MDA). The MDA content of lung tissue in nanomoles per gram increased from a control value of 48 +/- 8 to 98 +/- 18 at 5 h postendotoxin (2 micrograms/kg), whereas lung lymph protein transport (Cp), was increased 3- to 4-fold. The MDA content returned to base line with Cp by 24 h postendotoxin. Six sheep given endotoxin were pretreated with 12.5 mg/kg of ibuprofen, and six were infused with dimethylthiourea (DMTU) 0.75 g/kg. With ibuprofen, Cp was only increased 2.5- to 3-fold and MDA was increased to 69 +/- 15 nmol/g. With DMTU, the increase in Cp was comparable to that with endotoxin alone, as was the MDA of lung tissue with a value of 92 +/- 12 nmol/g. The correlation of tissue MDA with Cp in all animals was 0.83. We conclude that lipid peroxidation occurs in lung tissue after a moderately severe endotoxin injury with the degree of change corresponding to the degree of increased Cp.

Animals↗
PubMed1986

Rheumatoid arthritis synovial membrane contains a 62,000-molecular-weight protein that shares an antigenic epitope with the Epstein-Barr virus-encoded associated nuclear antigen.

A monoclonal antibody, selected for reactivity with the Epstein-Barr virus (EBV)-encoded antigen EBNA-1, exhibited strong reactivity with the synovial lining cells in joint biopsies from 10 of 12 patients with rheumatoid arthritis (RA) and adherent cells eluted from these tissues. No staining of RA synovial membrane frozen tissue sections or eluted synovial-lining cells was obtained with monoclonal antibodies directed against other EBV-encoded antigens (anti-p160, anti-gp200/350) or with monoclonal antibodies directed against antigens encoded by cytomegalovirus, herpes simplex viruses, or human T cell leukemia virus type I. Among 12 osteoarthritis and normal synovial biopsies only rare reactive cells were noted. Characterization of the antigen(s) in RA synovium by the Western immunoblotting technique revealed a 62,000-molecular-weight (mol-wt) protein, in contrast to the 70,000-85,000-mol-wt EBNA-1 antigen found in EBV-transformed cells. The structural basis for the cross-reactivity of the RA synovial membrane 62,000-mol-wt protein and the EBNA-1 antigen appears to reside in the glycine-alanine rich region of these molecules. A rabbit antibody directed against a synthetic peptide (IR3-VI-2) derived from the glycine-alanine-rich region of EBNA-1 reacted with the 70,000-85,000-mol-wt EBNA-1 antigen in EBV-infected cells and with the 62,000-mol-wt molecule in RA synovial membrane extracts. Since strong antibody responses to EBNA-1 are known to exist in RA patients, these results suggest that immune responses to a cross-reactive antigen may play a role in the pathogenesis of RA.

Animals↗
PubMed1986

Oral problems in patients with Sjögren's syndrome.

Minor salivary gland biopsies are important in confirming the diagnosis of Sjögren's syndrome (SS) and in understanding its pathogenesis. Biopsies should be obtained through clinically intact mucosa and contain at least 4 evaluable lobules. Immunohistologic studies using monoclonal antibodies demonstrated that the majority of infiltrating lymphocytes are T cells (CD3+) of the helper/inducer (CD4+) subset. Transmission electron microscopy (EM) and scanning EM emphasize the presence of high endothelial venules in SS biopsis and do not reveal immune complexes at the basement membranes. Taken together, these results suggest that T cell mediated immune mechanisms are responsible for salivary gland destruction. Patients with SS present specific therapeutic problems. First, their decreased saliva production predisposes them to increased oral infections and periodontal disease. These causes of increased oral pain must be distinguished from flares of the underlying disease including vasculitis and from medication side effects. Difficulty in eating solid foods may contribute to poor nutrition and to stress in social situations. In certain patients, dental restorations and prosthetic implants may improve cosmetic appearance and oral function.

Humans↗
PubMed1986

Study of cardiovascular autonomic insufficiency in advanced cancer patients.

To determine the incidence of cardiovascular autonomic insufficiency (CAI), 43 patients with advanced breast cancer and 20 normal controls were evaluated using electrocardiographic tests (heart rate variation during deep breathing and Valsalva maneuver and upon standing) and clinical tests (blood pressure variation during hand grip tests and upon standing). Nutritional status, tumor mass, Karnofsky performance status (PS) score (0-100), and peripheral reflexes were also determined. Tests for CAI were abnormal in 43 patients (52%), versus seven of 100 in 20 controls (7%, P less than 0.001). In cancer patients, tests for CAI were more frequently abnormal in patients with PS less than 60 (P less than 0.01), basal heart rate greater than 100 (P = 0.05), and malnutrition (P less than 0.01). We conclude that CAI is a frequent finding in patients with advanced breast cancer and should be suspected mainly in patients with a low PS, tachycardia, or malnutrition. It is probably a multifactorial syndrome, and malnutrition, drugs, decreased activity, or paraneoplastic syndromes are all possible causes for CAI.

Autonomic Nervous System↗
PubMed1986

Stereoacuity in young children.

Previous investigations of stereopsis in children have found that stereoacuity improves gradually over time and does not reach adult levels until well into childhood. The unusually protracted period of development implied by these data is at odds with the development of other visual capacities, such as acuity, contrast sensitivity, increment thresholds, and flicker fusion. When tested on those dimensions, children, by the age of five, achieve thresholds that are only moderately higher than those achieved by adults. To determine if the elevated thresholds for stereopsis found in children could be attributable to the methods used to obtain them, the authors assessed stereoacuity of children, 3 to 5 yr of age, using a laboratory test combined with procedures designed to optimize the limited attentional, motivational, and response capabilities of young children. The thresholds obtained (median = 12.6 sec) are much lower than previously reported and are close, but not equal, to the thresholds of adults. These data suggest that the development of stereopsis is not unusually protracted relative to the development of other visual capacities. The elevation of threshold relative to adult values is similar to the shortfall found in studies of other visual capacities and has led investigators to suggest, and the authors concur, that children do not possess the sophisticated cognitive strategies that adults can employ when thresholds are approached and uncertainty is high. Given that interpretation, it is suggested that the maturation of stereoscopic capacity is nearly complete in children 3 to 5 yr of age.

Adolescent↗
PubMed1985

Computerized labor and delivery logbook. A first step to a perinatal database in a university-affiliated community hospital.

In response to rapidly expanding data collection and retrieval needs, a modest perinatal database was initiated. This database combines the ease of entry and retrieval and the continuous accessibility of a microsystem with the storage and back-up advantages of a minicomputer with programming and troubleshooting support. The described system requires no change in medical record keeping, permits data entry by nursing personnel, requires little editing and is reasonably priced.

Costs and Cost Analysis↗