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Biomedical subjects

J Wallace

Publications and source records attributed to J Wallace.

At least 55 records · Page 3Linked to original sources
PubMed1998

Genomic organization, chromosomal mapping, and promoter analysis of the mouse dentin sialophosphoprotein (Dspp) gene, which codes for both dentin sialoprotein and dentin phosphoprotein.

Our laboratory has reported that two major noncollagenous dentin proteins, dentin sialoprotein and dentin phosphoprotein, are specific cleavage products of a larger precursor protein termed dentin sialophosphoprotein (MacDougall, M., Simmons, D., Luan, X., Nydegger, J., Feng, J. Q., and Gu, T. T. (1997) J. Biol. Chem. 272:835-842). To confirm our single gene hypothesis and initiate in vitro promoter studies, we have characterized the structural organization of the mouse dentin sialophosphoprotein gene. This gene has a transcription unit of approximately 9.4 kilobase pairs and is organized into 5 exons and 4 introns. Exon 1 contains a noncoding 5' sequence, and exon 2 contains the transcriptional start site, signal peptide, and first two amino acids of the NH2 terminus. Exons 3 and 4 contain coding information for 29 and 314 amino acids, respectively. The remainder of the coding information and the untranslated 3' region are contained in exon 5. Chromosomal mapping localized the gene to mouse chromosome 5q21 in close proximity to other dentin/bone matrix genes. Computer analysis of the promoter proximal 1.6-kilobase pair sequence revealed a number of potentially important cis-regulatory sequences; these include the recognition elements of AP-1, AP-2, Msx-1, serum response elements, SP-1, and TCF-1. In vitro studies showed that the DSPP promoter is active in an odontoblast cell line, MO6-G3, with basal activity mapped to -95 bp. Two potential enhancer and suppresser elements were identified in the regions between -1447 and -791 bp and -791 and -95 bp, respectively. The structural organization of the dentin sialophosphoprotein gene confirms our finding that both dentin sialoprotein and dentin phosphoprotein are encoded by a single gene with a continuous open reading frame.

Amino Acid Sequence↗
PubMed1998

Size and number of epithelial cells washed from the cornea after contact lens wear.

Using the technique of Fullard and Wilson, tear samples were collected atraumatically from the corneas of 14 rigid gas permeable (RGP) contact lens wearers, 14 soft contact lens (SCL) wearers, and 22 controls who did not wear contact lenses. Samples were analyzed for the number, size, and contiguity of the cellular contents. Both RGP and SCL groups had, on average, significantly fewer cells per sample than controls (median values were 11 and 12 cells vs. 44). The difference remained significant even after a correction of three cells was applied to account for cells adherent to the lenses. Approximately 80% of epithelial cells from both lens wear and control eyes were found in isolation, whereas 20% were contiguous with 1 or 2 other cells. This result is compatible with the majority of epithelial cells having exfoliated from the surface of the cornea after detaching from their neighbors, rather than detaching in sheets of cells. The cell length and cell area were analyzed. RGP wearers had significantly smaller cells than controls, whereas SCL wearers had slightly (but significantly) larger cells. These results may reflect changes in the exfoliation mechanism of the corneal epithelium in contact lens wear.

Cell Count↗
PubMed1998

Pellagra in a woman using alternative remedies.

A young woman presented with pellagra. Dietary intake of niacin was in excess of recommended guidelines. She had a low body mass index and was taking a number of alternative remedies. Resolution was rapid with oral nicotinic acid and discontinuation of the remedies.

Adult↗
PubMed1998

Preventing disability and managing chronic illness in frail older adults: a randomized trial of a community-based partnership with primary care.

BACKGROUND: Effective new strategies that complement primary care are needed to reduce disability risks and improve self-management of chronic illness in frail older people living in the community. OBJECTIVE: To evaluate the impact of a 1-year, senior center-based chronic illness self-management and disability prevention program on health, functioning, and healthcare utilization in frail older adults. DESIGN: A randomized controlled trial. SETTING: A large senior center located in a northeast Seattle suburb. The trial was conducted in collaboration with primary care providers of two large managed care organizations. PARTICIPANTS: A total of 201 chronically ill older adults seniors aged 70 and older recruited through medical practices. INTERVENTION: A targeted, multi-component disability prevention and disease self-management program led by a geriatric nurse practitioner (GNP). MEASUREMENTS: Self-reported Physical function, physical performance tests, health care utilization, and health behaviors. RESULTS: Each of 101 intervention participants met with the GNP from 1 to 8 times (median = 3) during the study year. The intervention group showed less decline in function, as measured by disability days and lower scores on the Health Assessment Questionnaire. Other measures of function, including the SF-36 and a battery of physical performance tests, did not change with the intervention. The number of hospitalized participants increased by 69% among the controls and decreased by 38% in the intervention group (P = .083). The total number of inpatient hospital days during the study year was significantly less in the intervention group compared with controls (total days = 33 vs 116, P = .049). The intervention led to significantly higher levels of physical activity and senior center participation and significant reductions in the use of psychoactive medications. CONCLUSIONS: This project provides evidence that a community-based collaboration with primary care providers can improve function and reduce inpatient utilization in chronically ill older adults. Linking organized medical care with complementary community-based interventions may be a promising direction for research and practice.

Activities of Daily Living↗
PubMed1998

The effect of a teledermatology program on rural referral patterns to dermatologists and the management of skin disease.

Teledermatology can be defined as the use of imaging and telecommunications technologies to provide skin care services at a distance. The potential value of teledermatology is especially great in rural and medically underserved areas that do not have, or cannot support, providers specializing in the diagnosis and management of skin diseases. Rural patients and primary care providers should be able to use teledermatology as a greatly simplified and potentially less expensive means of referral to an urban dermatologist. In an effort to gauge the impact of a simple teledermatology system on referral patterns and the management of rural patients with skin disorders, we studied baseline rates of referral to dermatologists from five primary care clinics in rural Oregon. Economical, easy-to-use teledermatology systems were subsequently installed, and the effects on patient referral and management were recorded over time. The interim results suggest that primary care providers (PCPs) are reluctant to refer patients with skin conditions, even when the primary care providers confidence in the correct diagnosis and treatment plan for that condition are relatively low. The installation of a teledermatology system increases the number of patients referred for specialist evaluation dramatically, even while the number of in-person visits to specialists fell. Although diagnostic agreement between dermatologists and primary care providers was mixed, a marked difference was found in their recommended treatment plans. A number of cases were found in which use of the telemedicine technology system resulted in reversing conditions that had been poorly controlled for a number of years prior to teleconsultation. This work is important as an indicator that referral rates to dermatologists may be inappropriately low in rural areas of the U.S., and that use of teledermatology may improve this trend.

Dermatology↗
PubMed1997

Cancer incidence among an HIV-infected cohort. Pulmonary Complications of HIV Infection Study Group.

Malignancies, particularly Kaposi's sarcoma and non-Hodgkin's lymphoma (NHL), are associated with human immunodeficiency virus (HIV) infection. Cancer incidence among 1,073 asymptomatic HIV-infected individuals from the Pulmonary Complications of HIV Infection Study cohort, persons from six states followed from 1988 to 1994, was examined. Total cancer incidence was 3.99/100 person-years; for Kaposi's sarcoma, incidence was 2.64 cases/100 person-years, and for NHL, it was 1.18 cases/100 person-years. Total cancer (n = 156 cases) was higher among nonblacks than among blacks (rate ratio = 2.8, 95% confidence interval 1.3-6.1), with similar results for Kaposi's sarcoma and NHL. The rate of lung cancer (n = 5) among white, homosexual/bisexual males was 0.18 per 100 person-years, suggesting a high risk of lung cancer.

Adult↗
PubMed1997

Evaluation of laparoscopic Toupet fundoplication as a primary repair for all patients with medically resistant gastroesophageal reflux.

BACKGROUND: This prospective study assesses the outcome results in 100 consecutive patients with gastroesophageal reflux disease (GERD) treated with a laparoscopic Toupet fundoplication. METHODS: GERD was confirmed by 24-h pH study and/or esophagogastroduodenoscopy (EGD). Pre- and postoperative symptoms, operative times, and perioperative complications were recorded on standardized data forms. Early follow-up was at 3 months and late follow-up, including 24-h pH, manometry, and EGD was at 22 months. RESULTS: Preoperative symptoms included heartburn (92%), regurgitation (58%), water brash (39%), and dysphagia (39%). Mean operative time was 3.2 hours. There were no conversions to celiotomy and there were no mortalities. The perioperative complication rate was 14%; 6% (5/83) of patients reported heartburn at 3 months and 20% (15/74) at 22 months. Early and late dysphagia was 20% (17/83) and 9% (7/74), respectively; 24-h pH testing was abnormal in 90% of symptomatic patients (9/10), 39% of asymptomatic patients (12/31), and 51% overall. CONCLUSIONS: Despite early improvement in reflux symptoms following laparoscopic Toupet fundoplications, there is a high incidence of recurrent GERD. Symptomatic follow-up underestimates the true incidence of 24-h pH-documented reflux. Based on these results we cannot recommend the laparoscopic Toupet repair for GERD patients with normal esophageal motility.

Adult↗
PubMed1997

Inadequate calcium, folic acid, vitamin E, zinc, and selenium intake in rheumatoid arthritis patients: results of a dietary survey.

OBJECTIVES: To determine the adequacy of calcium, folic acid, vitamin E, zinc, and selenium intake in patients with rheumatoid arthritis (RA). METHODS: We conducted an observational study on 48 patients (13 men, 35 women; mean age, 64.5 years) with RA attending a specialty clinic in New Zealand comparing their dietary intake as measured by a 5-day dietary survey with recommended dietary intake (RDI) guidelines. Information on disease activity, functional ability, and drug therapy also was obtained. RESULTS: The percentage of patients who achieved the RDI was 23% for calcium, 46% for folic acid, 29% for vitamin E, 10% for zinc, and only 6% for selenium. Patients on methotrexate had a significantly reduced intake of folic acid as a percentage of RDI (P < .05) compared with those on other therapies. In contrast, dietary intake of iron and protein was largely adequate and unrelated to anemia. CONCLUSIONS: Patients with RA should receive dietary education or supplementation to bring their intake of calcium, folic acid, vitamin E, zinc, and selenium up to the RDI.

Adult↗
PubMed1997

A modified coaxial compound micropipette for extracellular iontophoresis and intracellular recording: fabrication, performance and theory.

Investigation of the identity and modes of action of neurotransmitters in the mammalian central nervous system can be facilitated by simultaneous intracellular recording of membrane potential and extracellular iontophoresis of agonists and antagonists. We describe here techniques for conveniently constructing a compound microelectrode, originally described by Sonnhof (Pflugers Arch 341, 351-358, 1973), suitable for such studies. The Sonnhof electrode consists of two components, a centraxial micropipette for recording membrane potential surrounded by a cylindrical array of 6 pipettes for iontophoresis. The cylindrical array tapers coaxially and terminates in 6 contiguous, crescent-shaped orifices surrounding the terminal portion of the central pipette, 25 - 50 microm from the tip. Pipettes were constructed from borosilicate glass tubing of 1-mm wall thickness having a 10-mm or 16-mm outer diameter. The resistances, flux and transport numbers for iontophoresis of glycine were measured for pipettes constructed from both sizes of glass. Flux increased with increasing levels of current, and transport number decreased with increasing micropipette resistance. A spherical diffusion model points out the steep dependence of steady state concentration on diffusional distance, stressing the importance of diminishing the distance between the iontophoresis source and the recording site. This is particularly true when brief pulses of current are used.

Animals↗
PubMed1997

Reduction of exposure to laboratory animal allergens in the workplace.

OBJECTIVES: Evidence is now accumulating that the prevalence of allergy to laboratory animals is related to the intensity of exposure to animal allergens. Whilst airborne animal allergen concentrations may be influenced by the litter type, cage design and stock density, the effectiveness of methods to reduce personal exposure has not been objectively assessed. METHODS: Air samples were collected at 2 L/min and 180 L/min onto polytetrafluoroethylene (PTFE) filters and the rat urinary aeroallergen (RUA) and mouse urinary aeroallergen (MUA) concentrations were measured by radioallergosorbent test (RAST) inhibition. RESULTS: When 545 mice (11.l mice/m3) were housed in ventilated cages (Thoren Maximiser cage system) operated at positive pressure to the environment, the static MUA concentration (n = 24, median = 0.10 microg/m3) was reduced sevenfold when compared with conventional cage systems (n = 12, median =0.67 microg/m3, P< 0.001). MUA could be further reduced if the ventilated cage system was operated at lower pressure; static samples (n = 1) collected at 180 L/min at negative, ambient and positive pressure registered < 0.003, 0.02 and 0.28 microg/m3, respectively. During cleaning out, the intensity of personal exposure to RUA was apparently reduced twofold when soiled litter was removed by vacuum (n = 17, median = 22.87 microg/m3) when compared with tipping (n = 18, median = 38.15 microg/m3), P = 0.002) although the task took twice as long to perform. The RUA exposure associated with handling rats was'reduced 25-fold when performed in a ventilated cabinet (n = 21, median = 2.67 microg/m3) compared with handling of rats on an open bench (n = 17, median = 54.39 microg/m3, P = 0.0001). CONCLUSIONS: Effective reduction of exposure to animal allergens can now be achieved by the use of ventilated systems both for housing and handling rats and mice providing safety equipment is used correctly. The vacuum removal of soiled litter during the task of cleaning out was less efficient and additional respiratory protection is therefore recommended for this procedure.

Air Pollutants, Occupational↗
PubMed1997

Healthy aging. A women's issue.

The life expectancy of women currently exceeds that of men by almost seven years, yet women spend approximately twice as many years disabled prior to death as their male counterparts. The diseases that account for death and health care utilization in older women (heart disease, cancer, stroke, fracture, pneumonia, osteoarthritis, cataracts) are also major contributors to disability. This paper reviews the scientific evidence that supports specific recommendations for older women that may prevent or delay these conditions for as long as possible. Risk factors for falls and fractures should be assessed and, where possible, modified. Adequate intakes of calcium, vitamin D, fruits, and vegetables should be encouraged. Weight should be monitored and weight loss discouraged for most women. Screening for B12 deficiency is recommended. Engaging women in a shared decision-making process about the use of hormone replacement therapy for longterm prevention of heart disease and fractures is important, as is regular screening for breast and colo-rectal cancer. Women should be encouraged to engage in enjoyable physical activities, including walking, for 30 minutes daily. These interventions have the potential to delay the onset and improve the course of many chronic conditions that prevail in later life.

Age Distribution↗
PubMed1996

Overall and cause-specific mortality in a cohort of homo-/bisexual men, injecting drug users, and female partners of HIV-infected men. Pulmonary Complications of Human Immunodeficiency Virus Infection Study Group.

OBJECTIVE: To study the overall and cause-specific HIV-related mortality in a cohort of HIV-seropositive subjects according to transmission category, race/ethnicity, sex and severity of immunosuppression. DESIGN: A cohort of 1129 HIV-seropositive homo-/bisexual men, injecting drug users, and female partners of HIV-infected men were enrolled at six centers in San Francisco, Los Angeles, Chicago, Newark, Detroit and New York between 1 November 1988 and 1 November 1989. Subjects were evaluated every 6 months at least until 31 March 1994. METHODS: The analyses of overall mortality for the subgroups of interest were performed with Kaplan-Meier plots and Cox proportional hazards models. Cause-specific analyses were performed on the primary cause of death using rates per 100 person-years of exposure. RESULTS AND CONCLUSIONS: Baseline severity of immunosuppression is the strongest predictor of mortality. There were no statistically significant differences in overall HIV-related mortality among transmission categories, race/ethnicity groups or sexes. There were differences, however, in cause-specific mortality among the different risk groups.

AIDS-Related Opportunistic Infections↗
PubMed1996

Girl Talk: development of an intervention for prevention of HIV/AIDS and other sexually transmitted diseases in adolescent females.

The number of adolescent females between the ages of 13 and 19 who are contracting sexually transmitted diseases (STDs) is rising at an alarming rate. Although the issue of STDs has been overshadowed by continued public debate over adolescent pregnancy and childbearing, it demands attention. Particularly concerning is the fact that STDs increase the likelihood of transmitting HIV (N.E. MacDonald et al., 1990). To offset the growing incidences of STDs among female adolescents, gender-specific interventions are needed. Following is a description of the theoretical underpinnings that informed and guided the development of a gender-specific intervention titled Girl Talk. A two-stage creation and review process was used to design this 2.5-hr, four-session intervention. An overview of the quasi-experimental design that compared a nonequivalent comparison and two intervention groups (peer led and adult led) is presented. Baseline characteristics of the three groups are reported. Also described is how participant feedback and a design content analysis are used to evaluate the appropriateness of the intervention for adolescent females.

Adolescent↗
PubMed1995

Cytoprotective effects of CI-959 in the rat gastric mucosa: modulation of leukocyte adhesion.

BACKGROUND & AIMS: CI-959 is an anti-inflammatory agent that inhibits neutrophil adhesion, respiratory burst, and mast cell histamine release in vitro. In view of the emerging role of neutrophils in gastric erosive damage, the goals of this study were to assess the gastric cytoprotective effects of CI-959 and identify the mechanism responsible for this action. METHODS: Cytoprotective effects in the rat nonsteroidal anti-inflammatory drug and ethanol erosion models were assessed using image analysis. The in vivo effects of CI-959 on gastric acid secretion, arachidonic acid metabolism, and intracellular sulfhydryl and leukocyte adhesion were also examined. RESULTS: CI-959 protected prophylactically against the erosive damage induced by aspirin, indomethacin, and ethanol with 50% effective doses (ED50s) of 0.05, 1.0, and 0.07 mg/kg administered orally, respectively. When administered after indomethacin or ethanol, CI-959 had no effect on the healing of erosive damage. CI-959 did not alter gastric acid secretion, arachidonic acid metabolism, or intracellular sulfhydryl levels. In vivo, CI-959 blocked leukocyte adhesion in intravital microscopy studies using indomethacin (ED50, < 5 mg/kg orally) or platelet-activating factor (50% inhibiting concentration, approximately 10 mumol/L) as the adhesion stimulus. CONCLUSIONS: The most likely mechanism responsible for the cytoprotective effects of CI-595 is its inhibitory effects on leukocyte trafficking and/or adhesion.

Animals↗
PubMed1995

Determinants of HIV risk among men who have homosexual sex and inject drugs.

Men with histories of both homosexual contact and injecting drug use (IDU) are at increased risk of HIV infection over men who have only one such risk. Despite this, their special needs and circumstances have been neglected by AIDS prevention programmes. A survey of a wide spectrum of homosexual male IDUs was carried out in Melbourne and Sydney in 1993 to inform the development of specific policy and programmes for HIV prevention in these subcultures. Of 169 men, self-reported HIV prevalence was 27%. Decreasing compliance with safe sex guidelines (as measured by numbers of casual partners, participation in anal intercourse and use of condoms) was associated with HIV seropositivity, increased age, and increased participation in sex work; having a regular male partner was not protective against unsafe sexual behaviour, no matter the length of the relationship. A substantial proportion (15%) reported inconsistent condom use during anal sex with more than two partners in the preceding month: they were slightly more likely to be engaging in sex work, less 'stable' and more likely to be HIV infected. Sexual risk was not strongly associated with unsafe injecting, which was in general safe. Men who both have homosexual sex and inject drugs are groups at high risk of HIV, more from unsafe sex than from shared injecting equipment; men who believed themselves to be HIV infected were continuing to have sex in such a way that would allow transmission. These are clearly groups in need of priority targeted interventions.

Adolescent↗