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Biomedical subjects

S R Johnson

Publications and source records attributed to S R Johnson.

At least 73 records · Page 4Linked to original sources
PubMed1995

Perinatal transmission and maternal risks of human papillomavirus infection.

We conducted a prospective study to investigate whether human papillomavirus (HPV) could be vertically transmitted to neonates. Pregnant women (N = 203) were tested for HPV DNA infection during the third trimester and again during labor prior to delivery. Their newborns (N = 203) were tested 1 to 3 days after delivery. Among the mothers, 12.3% (N = 25/203) typed HPV positive at either or both maternal specimen collection periods, whereas only 1.0% of the neonates (N = 2/203) typed positive. This low transmission rate may be due in part to the fact that 65% of mothers who were HPV positive during the third trimester tested HPV negative by labor/delivery. The higher frequency of risks associated with maternal HPV infection were similar to those found in studies of cervical dysplasia and cancer: younger age at first intercourse and first pregnancy, number of sexual partners, and longer duration in use of oral contraceptives. In addition, those who were past smokers and had a shorter recency and latency period in smoking were more likely to be detected with HPV.

Adolescent↗
PubMed1994

How nutrition policy affects food and agricultural policy.

The impact of the improved understanding of nutrition and the importance of the diet in nutrition status has had subtle but far-reaching consequences for food and agricultural policy. Many of the changes in the food supply are in response to increased consciousness of diet, nutrition and health status. The simple connection between nutrition policy and food and agricultural policy follows from the sovereignty of the consumer. Nutrition policy influences consumers' attitudes and choices. These impact the behavior of agents in the food and production system. And, if properly designed, food and agricultural policies can accelerate the process of adapting the production and distribution systems for agriculture and food to better meet the demands of the more informed consumer. Policies that reflect the behavior of consumers and supply better information to the agents in the food and agricultural system will be the most effective.

Agriculture↗
PubMed1994

Dome-shaped lesion on chest radiograph: retroperitoneal abscess dissecting through the posterior chest wall.

A 50-year-old man with an 8 x 4 cm mass on the posterior chest was found to have a large retroperitoneal abscess due to Klebsiella pneumoniae. The abscess dissected through the right lower lobe of the lung and the posterior chest wall to produce a subcutaneous mass. The source of the posterior chest wall mass appeared to be a perinephric abscess. A dome-shaped lesion above the right hemidiaphragm on chest radiograph resolved immediately with surgical drainage, suggesting that an abscess should be a prime consideration when one observes such a lesion on a chest film.

Abscess↗
PubMed1994

What do minority elementary students understand about the causes of acquired immunodeficiency syndrome, colds, and obesity?

Elementary school-age children's conceptual understanding and factual knowledge about the causes of acquired immunodeficiency syndrome (AIDS), colds, and obesity are poorly understood, particularly among black children living in low-income, urban neighborhoods. We examined minority children's conceptual understanding about the causes of these illnesses. In addition, children's knowledge and misconceptions about the causal agents of AIDS, colds, and obesity were investigated. A developmentally based, semistructured interview was developed to measure children's level of understanding about the causes of each condition. Interviews were conducted with 239, predominately black, first, third, and fifth grade students attending two public elementary schools in a low income city in northern California. Interviews were verbally administered and tape recorded for later verbatim transcription. Children's responses to questions about causality first were scored based on their level of conceptual sophistication. Responses then were assigned to thematic categories reflecting the children's factual knowledge about the causes of AIDS, colds, and obesity. Increases in grade level were associated with higher scores for causality of AIDS (p < .0001), colds (p < .0001), and obesity (p < .01). In all three conditions, causality scores increased between first and fifth grades, but did not significantly vary between third and fifth grades. Gender, socioeconomic status, and number of adults living in the household were not significantly associated with causality scores. Within each grade, the finding of lower causality scores for AIDS, as compared to colds and obesity, points out the need for developmentally appropriate explanations to children about the causes of AIDS.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1993

Characterization of a catalase-deficient strain of Neisseria gonorrhoeae: evidence for the significance of catalase in the biology of N. gonorrhoeae.

We obtained a catalase-deficient (Kat-) strain of Neisseria gonorrhoeae isolated from a patient who had been unsuccessfully treated with penicillin. Quantitative enzyme assays and electrophoresis of cell extracts on native polyacrylamide gels subsequently stained for catalase and peroxidase activities failed to detect both enzymes. The strain exhibited no growth anomalies or unusual requirements when grown under ordinary laboratory conditions. However, the Kat- strain proved extremely sensitive to exogenous hydrogen peroxide, and analysis of the bacterial DNA after such exposure showed extensive single-strand breakage in both chromosomal and plasmid DNAs. Partial characterization of the gonococcal catalase from a Kat+ laboratory strain revealed that the enzyme had the physical and chemical properties of both catalase and peroxidase.

Acatalasia↗
PubMed1993

Avoiding nerve damage during elbow arthroscopy.

To define the anatomical relationships of the nerves to the common arthroscopy portals at the elbow an arthroscope was introduced into 20 cadaver elbows and the positions of the nerves were then determined by dissection. In all cases the posterior interosseous nerve lay close to the radiohumeral joint and to the anterolateral portal. Pronation of the forearm displaced the nerve away from the arthroscope. The median nerve passed consistently within 14 mm of the arthroscope when it was introduced through the anteromedial portal. The branches supplying the superficial forearm flexor muscles were at risk.

Arthroscopy↗
PubMed1993

Contraception.

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Contraception↗
PubMed1993

Understanding of acquired immunodeficiency syndrome by elementary school children--a developmental survey.

OBJECTIVES: The developmental process by which young children acquire an understanding of the concepts of causality, treatment, and prevention of illness as related to acquired immunodeficiency syndrome (AIDS) is poorly understood. Previous studies have focused on adolescent populations and have measured the facts that children seem to know rather than their understanding of relevant concepts. Such approaches are likely to overestimate the child's true level of understanding and obscure significant misconceptions. The aims of this project are to measure directly the level of understanding of the concepts of causality, treatment, and prevention of AIDS in healthy, elementary school children and to assess the sociodemographic variables associated with their conceptual understanding. METHODS: Using a new, developmentally based, semistructured interview protocol (ASK, AIDS Survey for Kids), 361 children (57% black, 24% Hispanic, 19% white) in kindergarten through sixth grade at four public schools in New Haven, CT were interviewed. Responses to questions about causality, treatment, and prevention were scored for each of three illnesses (AIDS, and for comparison, colds and cancer) based on the level of conceptual sophistication of the response, irrespective of its factual accuracy. RESULTS: Scores for each of the concepts were highly intercorrelated and were correlated most strongly with grade level (R = .31 to .50, P < .0001 for each of these correlations, with the exception of the treatment of AIDS). Gender, race, and socioeconomic status did not contribute significantly to the variance observed for any of the concept scores in a linear regression model. Over-all, children's level of understanding of causality was significantly less sophisticated for AIDS than for colds (P < .0001); their level of conceptual understanding for the causality of AIDS was not significantly different from that of cancer (P = .9). CONCLUSIONS: Children's understanding of causality, treatment, and prevention of AIDS, as measured by the ASK, follows the same developmental sequence reported for children's understanding of general physical illness. Sociodemographic variables, such as race, gender, and socioeconomic status do not affect children's level of sophistication of these developmental concepts. These results have implications for the creation of developmentally appropriate and effective AIDS education curricula for primary and elementary grades. They also offer guidance to health care providers in their efforts to educate parents and young children about this important topic.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Twitch and tetanus in mdx mouse muscle.

We compared mdx and C57BL10 anterior tibial muscle force in situ (single pulse, multiple pulse, staircase, posttetanic potentiation, and fatiguing stimulation patterns) to define muscle strength, physiology, and fatigue resistance. The relatively hypertrophied mdx muscle showed: reduced strength (N/cm2), an increased twitch-tetanus ratio, and resistance to post-fatigue twitch slowing. These differences implicate altered mdx calcium regulation, and emphasize the importance of measuring both muscle function and morphology in mdx treatment trials.

Animals↗
PubMed1992

The association between hemoglobin and behavior problems in a sample of low-income Hispanic preschool children.

This cross-sectional study, conducted in 1988, examines the association between hemoglobin level and behavior problems in 236 Hispanic children, ages 2 to 5 years, residing in low-income census tracts in the Los Angeles area. Venous blood samples were analyzed for hemoglobin, mean corpuscular volume, free erythrocyte protoporphyrin, and lead. Family and child data were obtained through a home interview with the child's mother or guardian. Behavior problems were assessed using questionnaires modeled after Child Behavior Checklists for children ages 2 to 3 and 4 to 5 years. A significant correlation between decreasing hemoglobin values and increasing total behavior problems scores was found for girls, 2 to 3 and 4 to 5 years old. These associations remained significant in both age groups after adjusting for maternal education and marital status. Statistically significant inverse correlations also were found between hemoglobin and social withdrawal, sleep problems, and depression (internalizing subscale behaviors) in 2- to 3-year-old girls, and between hemoglobin and aggression and hyperactivity (externalizing subscale behaviors) in 4- to 5-year-old girls. The potentially negative consequences of these anemia-related behavior problems on children's development, learning ability, and parent-child relationships warrant further investigation.

California↗
PubMed1991

Novel plasmid combinations in Haemophilus ducreyi isolates from Thailand.

Thirty isolates of Haemophilus ducreyi collected in Thailand in 1984 were characterized by plasmid content. Three novel plasmids with estimated molecular masses of 1.8, 2.6, and 2.8 MDa were observed in 29 isolates, in addition to the 3.2-, 5.7-, and 7.0-MDa beta-lactamase and 4.4-MDa sulfonamide resistance plasmids. At least three of the seven plasmids were observed in each of the 29 isolates. The number and diversity of plasmids observed in these isolates of H. ducreyi distinguish them from strains previously described.

Chancroid↗
PubMed1991

Perinatal vertical transmission of human papillomavirus and subsequent development of respiratory tract papillomatosis.

This study prospectively examined the potential for human papillomavirus (HPV) to be transmitted vertically to newborns during delivery. Exfoliated cervical cells were extracted from 72 pregnant women during the third trimester and again during labor prior to delivery, and tested for the presence of HPV DNA. These results were compared with HPV DNA specimens from their newborns, who were sampled by exfoliated cells from the oral-pharyngeal cavity and vulva or tissue from the foreskin 24 to 72 hours after delivery. Among the mothers, 18.1% (13 of 72) typed HPV-positive by the ViraPap/ViraType DNA hybridization technique. Two neonates (2.8% or 2 of 72) tested positive from oral-pharyngeal specimens. This finding supports the hypothesis that respiratory tract papillomatosis may develop as a result of perinatal vertical transmission of HPV. Furthermore, this study suggests that neither cesarean section nor prepartum treatment of HPV lesions will always protect against neonatal acquisition of HPV.

Adult↗
PubMed1991

The association between pregnancy and human papilloma virus prevalence.

This study examined the effects of pregnancy on the prevalence of HPV infection, comparing 69 pregnant and 54 nonpregnant age-frequency matched female patients. HPV prevalence was detected by DNA hybridization using the ViraPap/ViraType dot blot procedure. The prevalence of HPV among pregnant women increased with gestational age from 8.0% in the first trimester, to 16.7% in the second, and 23.1% in the third trimester. This finding suggests that HPV infection may be activated by hormonal or other effects of pregnancy and may explain why number of pregnancies is known to be associated with increased risk of cervical dysplasia and cancer. Oncogenic HPV types 16/18 and 31/33/35 were identified with almost equal frequency in the study population whereas HPV 6/11 was seen rarely. The logistic regression models indicate that there were no significant differences between HPV positive and HPV negative groups by age, income, number of sex partners, age of first intercourse, average frequency of intercourse per month, number of pregnancies, oral contraceptive duration, or pregnancy status. There were no interaction effects. A current Pap result of cervical dysplasia (OR = 8.9; 95% confidence interval: 2.1, 38.8), oral contraceptive use (OR = 0.1; 0.03, 0.6), and education (OR = 1.4; 1.1, 1.8) were significant predictors of HPV status.

Adolescent↗
PubMed1991

Problems encountered with the Bethesda System: the University of Iowa experience.

This paper provides a descriptive summary of 1 year's experience with the Bethesda Cytologic Classification System at the University of Iowa Hospitals and Clinics. Cytotechnologists and pathologists criticized the failure of the new classification system to provide microscopic criteria for the following categories: adequacy of the smear (satisfactory, less than optimal, unsatisfactory), atypical squamous cells of undetermined significance, atypical glandular cells of undetermined significance, and inflammation-associated changes. Clinicians criticized the "less than optimal" category and the reporting of koilocytosis, moderate dysplasia, and endometrial cells. Suggestions for modifying the Bethesda System include: eliminating the less than optimal response, defining what constitutes an unsatisfactory smear, eliminating the terms low-grade and high-grade squamous intraepithelial lesion, and changing the reporting of endometrial cells.

Attitude of Health Personnel↗