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Biomedical subjects

L Gee

Publications and source records attributed to L Gee.

52 records · Page 3Linked to original sources
PubMed1997

Living arrangements, changes in living arrangements, and survival among community dwelling older adults.

OBJECTIVES: This study examines whether living arrangements and changes in living arrangements are associated with survival among older community-dwelling adults, and whether differences in health status account for observed differences in survival. METHODS: The sample consisted of 5085 persons aged 70 years or older who had participated in the Longitudinal Study of Aging in 1984 and 1986. Proportional hazards models were used to examine associations of survival time through 1990 with living arrangements in 1984 and with changes in living arrangements from 1984 to 1986. RESULTS: Women who lived with someone other than a spouse at baseline or who changed from living with a spouse to living with someone other than a spouse were at greater risk of dying than women in other living arrangements, independent of health status or functioning. Among men, survival time was not generally associated with baseline living arrangements. CONCLUSIONS: Older adults who live alone or who change from living with someone to living alone do not have an increased mortality risk. However, living with or changing to living with someone other than a spouse may be associated with increased mortality risk.

Activities of Daily Living↗
PubMed1996

CnNK-2, an NK-2 homeobox gene, has a role in patterning the basal end of the axis in hydra.

NK-2-class homeobox genes have been identified in a variety of metazoans, from sponges to arthropods and vertebrates, and have been shown to play roles in a variety of cell and tissue specifications. Here we describe the characterization of the NK-2 homolog CnNK-2 from Hydra vulgaris, a freshwater cnidarian. CnNK-2 expression is restricted to the endodermal epithelial cells of hydra and is primarily in the peduncle, the lower end of the body column. In some species it is graded along the apical-basal axis with a maximum in the basal tissue of the lower peduncle, adjacent to the foot. CnNK-2 expression invariably precedes foot formation as part of the normal tissue dynamics of the adult as well as during asexual reproduction by budding, foot regeneration, or ectopic foot formation. Manipulations which alter the gradient of positional value along this axis affect CnNK-2 expression in a manner which indicates that expression of this gene is closely linked to the gradient. The normal and altered patterns of expression of this gene extend the understanding of the regulation of foot formation in hydra.

Amino Acid Sequence↗
PubMed1996

Spectroscopic changes in human dentine exposed to various storage solutions--short term.

OBJECTIVES: Tooth storage conditions in studies of dentine have not been standardized. The objective of this investigation was to determine the effects of storage solution and time on dentine, using spectroscopic methods. METHODS: Twenty-seven dentine disks (0.75 mm thick) were prepared from freshly extracted third molars with documented histories. The teeth were sectioned parallel to the occlusal plane using a diamond saw. Specimens were analysed non-destructively for surface chemical changes using specular reflectance infra-red Fourier transform spectroscopy (SRIFTS), and changes in optical properties were measured in the ultraviolet, visible and near-infra-red spectral ranges with an integrating sphere spectrophotometer (UV/VIS/NIR) before and after storage. A minimum of five specimens were stored in distilled water with 0.02% thymol, purified and filtered water, phosphate buffered saline with 0.02% thymol, 70% ethanol or 10% buffered formalin and evaluated at 0, 1, 2, 7, 14, 21 and 28 days. After each measurement, specimens were stored in fresh solutions. IR spectra were obtained from 4400 to 400 wave-numbers (cm-1). Optical properties of reflectance and transmittance were determined from 200 to 2500 nm, and absorbance was calculated. RESULTS: Analysis of the IR spectra indicated no significant differences in collagen or mineral peak positions for any solution at any time period. There were significant differences in peak intensities of dentine stored in distilled water, purified and filtered water and phosphate-buffered saline over time in the IR spectra. Furthermore, differences in optical properties of dentine disks were detected by UV/VIS/NIR. CONCLUSION: It was concluded that changes in surface chemistry and optical properties of dentine occur as a function of storage solution and time, which must be considered when studying dentine.

Anti-Infective Agents↗
PubMed1996

Risk factors for herpes simplex virus epithelial keratitis recurring during treatment of stromal keratitis or iridocyclitis. Herpetic Eye Disease Study Group.

AIMS: Possible risk factors were evaluated for herpes simplex virus (HSV) epithelial keratitis in patients with stromal keratouveitis. METHODS: The study population included 260 patients who had active stromal keratitis and/or iridocyclitis without epithelial disease and who were enrolled in one of three clinical trials of the Herpetic Eye Disease Study. Study treatment involved a 10 week course of topical placebo, topical prednisolone phosphate, or topical prednisolone phosphate with oral acyclovir. All groups received topical trifluridine four times daily for 3 weeks then twice daily for another 7 weeks. Patients were examined for HSV epithelial keratitis for 16 weeks. RESULTS: Dendritic or geographic epithelial keratitis occurred in 12 (4.6%) study patients. Adverse effects attributable to trifluridine prophylaxis were acute allergic blepharoconjunctivitis in 10 (3.8%) study patients and corneal epithelial erosions in 11 (4.2%) study patients. No significant difference in the occurrence of HSV epithelial keratitis was found among the study treatment groups: one (2.0%) of 49 topical placebo treated patients, nine (6.5%) of 138 patients treated with topical corticosteroids without acyclovir, and two (2.7%) of 73 patients treated with topical corticosteroids and oral acyclovir. Univariate exponential models suggested that patients with a history of previous HSV epithelial keratitis and non-white patients were more likely to develop HSV epithelial keratitis during treatment of stromal keratouveitis. CONCLUSION: Individuals with prior HSV epithelial keratitis and certain ethnic groups may have a higher rate of recurrent epithelial keratitis during the acute treatment of HSV stromal keratouveitis.

Acyclovir↗
PubMed1994

Herpetic Eye Disease Study. A controlled trial of oral acyclovir for herpes simplex stromal keratitis.

PURPOSE: To evaluate the efficacy of oral acyclovir in treating stromal keratitis caused by herpes simplex virus (HSV) in patients receiving concomitant topical corticosteroids and trifluridine. METHODS: The authors performed a randomized, double-masked, placebo-controlled, multicenter trial in 104 patients with HSV stromal keratitis without accompanying HSV epithelial keratitis. Sample size was chosen so that a 5%, one-tailed test would have an 80% chance of detecting a doubling of the median time to treatment failure. Patients were randomized to receive a 10-week course of either oral acyclovir (400 mg 5 times daily, n = 51) or placebo (n = 53). All patients also received a standard regimen of topical prednisolone phosphate and trifluridine. Ophthalmologic examinations were performed weekly during the 10-week treatment period, every 2 weeks for an additional 6 weeks, and at 6 months after entry into the trial. RESULTS: The median time to treatment failure (defined as worsening or no improvement of stromal keratitis or an adverse event) was 84 days (95% confidence interval, 69-93 days) for the acyclovir group and 62 days (95% confidence interval, 57-90 days) for the placebo group. By 16 weeks, 38 patients (75%) in the acyclovir group and 39 patients (74%) in the placebo group had failed treatment. Also by that time, the keratitis had resolved with trial medications, and there was no subsequent worsening in nine patients (18%) in the acyclovir group and ten (19%) in the placebo group. None of these results were significantly different between the two groups. However, visual acuity improved over 6 months in significantly more patients in the acyclovir group than in the placebo group. CONCLUSION: There was no statistically or clinically significant beneficial effect of oral acyclovir in treating HSV stromal keratitis in patients receiving concomitant topical corticosteroids and trifluridine with regard to time to treatment failure, proportion of patients who failed treatment, proportion of patients whose keratitis resolved, time to resolution, or 6-month best-corrected visual acuity. Visual acuity improved over 6 months in more patients in the acyclovir group than in the placebo group.

Acyclovir↗
PubMed1994

Herpetic Eye Disease Study. A controlled trial of topical corticosteroids for herpes simplex stromal keratitis.

PURPOSE: To evaluate the efficacy of topical corticosteroids in treating herpes simplex stromal keratitis. METHODS: The authors performed a randomized, double-masked, placebo-controlled, multicenter clinical trial of 106 patients with active herpes simplex stromal keratitis who had not received any corticosteroids for at least 10 days before study enrollment. Patients were assigned to the placebo group (n = 49) or the steroid group (topical prednisolone phosphate; n = 57); both regimens were tapered over 10 weeks. Both groups received topical trifluridine. Visual acuity assessment and slit-lamp biomicroscopy were performed weekly for 10 weeks, every other week for an additional 6 weeks or until removal from the trial, and at 6 months after randomization. RESULTS: The time to treatment failure (defined by specific criteria as persistent or progressive stromal keratouveitis or an adverse event) was significantly longer in the steroid group compared with the placebo group. Compared with placebo, corticosteroid therapy reduced the risk of persistent or progressive stromal keratouveitis by 68%. The time from randomization to resolution of stromal keratitis and uveitis was significantly shorter in the steroid group compared with the placebo group even though both groups included patients who were removed from the study and treated with topical corticosteroids according to best medical judgment. Nineteen (33%) of the steroid-treated patients and 11 (22%) of the placebo-treated patients completed the 10 weeks of protocol therapy and had stable, noninflamed corneas after 16 weeks. At 6 months after randomization, no clinically or statistically significant differences in visual outcome or recurrent herpetic eye disease were identified between the steroid and placebo groups. CONCLUSIONS: The topical corticosteroid regimen used in this study was significantly better than placebo in reducing persistence or progression of stromal inflammation and in shortening the duration of herpes simplex stromal keratitis. Postponing steroids during careful observation for a few weeks delayed resolution of stromal keratitis but had no detrimental effect as assessed by visual outcome at 6 months.

Administration, Topical↗
PubMed1993

Expression of Cnox-2, a HOM/HOX gene, is suppressed during head formation in hydra.

Using PCR, six genes of the HOM/HOX class have been identified in hydra. One of them, Cnox-2, has been sequenced and resembles the Deformed gene of Drosophila. As shown previously, the expression pattern of Cnox-2 suggested that it may be involved in axial patterning as it was strongly expressed in the epithelial cells of the body column and foot, but only weakly expressed in the head. In addition, expression of Cnox-2 decreased sharply in body column tissue as it was converted into head tissue, thereby providing further support for a role in hydra pattern formation. To examine this possibility further, additional manipulations were carried out which convert body column tissue into either head or foot tissue. When body column tissue was converted into head tissue by regeneration, transplantation, or during budding, Cnox-2 expression was sharply reduced, indicating that expression of this gene is suppressed during head formation. When body column tissue was converted into foot tissue by regeneration or Li+ treatment, the changes in Cnox-2 expression patterns indicated that Cnox-2 had no direct role in foot formation. Surprisingly, however, the observed changes in Cnox-2 expression patterns indicate that following bisection, both head and foot regeneration processes are initiated at the injured edge of the bisected animal.

Animals↗
PubMed1993

Storage effects on dentin permeability and shear bond strengths.

The effects of duration of storage and selection of storage solution upon dentin permeability and bond strength were studied over a period of 8 days to 6 mon. Teeth were stored immediately after extraction in one of five commonly used solutions: 70% ethanol (E); 10% formalin (F); distilled water (W); distilled water with thymol (WT); or phosphate-buffered saline with thymol (ST). Permeability and lap shear bond strength measurements were evaluated in a repeated measures design (n = 20) after 8 days, 15 days and 6 mon. Dentin permeability varied with solution type and duration of storage as demonstrated by ANOVA, increasing F, E and the water-based solutions, respectively. Saline storage resulted in large significant decreases in permeability after prolonged storage, suggesting changes in dentin. Bond strengths were unaffected by duration of storage or by solution type, except for saline. Thus, permeability and bond strength values may be affected by storage conditions. The results of this study indicate that saline, the most commonly used solution in dental materials research, may be unsuitable for use as a result of its effect on dentin permeability and bond strength.

Analysis of Variance↗
PubMed1979

Angiotensin convertase activities in human alveolar macrophages: effects of cigarette smoking and sarcoidosis.

Angiotensin I convertase activity has been found in human alveolar macrophages from normal volunteers and patients with pulmonary sarcoidosis. This activity is higher in the alveolar macrophages from smokers than from nonsmokers, and is even more elevated in sarcoid patients. The activity can be detected with both angiotensin I and bradykinin analogs and appears to require protein synthesis, but the enzyme is not secreted by alveolar macrophages in culture.

Granuloma↗
PubMedDate not supplied

Contemporary psychosocial issues in cystic fibrosis: treatment adherence and quality of life.

This review focuses on the two major psychosocial areas currently topical in cystic fibrosis research: treatment adherence and quality of life. First, the paper discusses the importance of evaluating adherence to treatments and medical advice, its measurement, predictors of adherence and non-adherence and whether the data should be used to inform clinical practice and policy decisions. Second, the purpose of evaluating quality of life in cystic fibrosis and an overview of the data are discussed. Both areas have suffered from problems with terminology and definition, inappropriate methodologies and hence difficulties with data interpretation. Future directions for research are advocated.

Adaptation, Psychological↗
PubMedDate not supplied

Microstructure of primary tooth dentin.

PURPOSE: This study was performed to determine variations in dentin microstructure from primary anterior teeth at specific areas and depths in relation to the dentin enamel junction, (DEJ). METHODS: Ten freshly extracted, non-carious primary maxillary anterior teeth were sectioned to provide two 1.0 mm x 1.0 mm matchsticks extending from the DEJ to the pulp chamber--one each from the central and distal regions of each tooth. Slices were prepared at distances of 0.15, 0.8, and 1.45 mm from the DEJ. Following polishing, each slice was examined in a wet scanning election microscope, (SEM) and tubule density, tubular diameter, and peritubular width were determined at nine grid locations. Statistical analyses were carried out using multi-factor ANOVA, Tukey's multiple comparisons, and linear regression to compare rates of change for each parameter. RESULTS: Tubule numerical density consistently decreased with distance from the DEJ. Decreases of 11,800 mm2/mm for canine distal matchsticks were significantly greater (P < 0.05) than the rate of 4,400 mm2/mm for canine central matchsticks. Rates for the lateral incisors were not significantly different. Tubule diameters increased with distance from the DEJ at rates of 0.28 micron/mm and 0.39 micron/mm for canines and lateral incisors, respectively, and there was a corresponding decrease in peritubular width. Microcanals or giant dentin tubules, 5-10 microns in diameter were incidently found in varying numbers in the midline of 4 of 20 teeth examined, including central and lateral incisors, but not in canines. CONCLUSIONS: The work shows substantial differences in the microstructure of primary dentin as compared to permanent dentin, substantial differences with location, and the relatively common occurrence of microcanals. Therefore, the area of solid dentin that is available for dentin bonding is significantly reduced, accounting for reported differences in bond strength. Such differences may be important factors in tooth sensitivity, susceptibility to trauma, and caries progression.

Analysis of Variance↗
PubMedDate not supplied

Relationship between drug use and sexual behaviors and the occurrence of sexually transmitted diseases among high-risk male youth.

BACKGROUND AND OBJECTIVES: Sexually active adolescents, especially those in detention, are at high risk for acquisition of sexually transmitted diseases (STDs), including HIV infection. Yet little information is available that describes their risk behaviors associated with STDs. The overall objective was to define the relationship between risk behaviors and STD acquisition among adolescents. GOALS OF THIS STUDY: The first goal was to characterize drug use and sexual behaviors that place a population of adolescent male detainees at STD/HIV risk. The second goal was to define possible interrelationships between drug use, especially alcohol use, and risky sexual behaviors with STD acquisition. STUDY DESIGN: The study group consisted of 414 adolescent male detainees 12 to 18 years of age who participated in an interview and a clinical assessment. Two hundred sixty-nine of the 414 subjects agreed to STD laboratory tests, including serologic testing for hepatitis B and syphilis, and urethral cultures to screen for chlamydial and gonorrheal urethritis. RESULTS: Results showed that 15% had current evidence of at least one STD, and 34% had a history or current evidence of at least one STD (STD occurrence). The subjects were frequently engaging in risky sexual and drug use behaviors. Two multivariate models described three factors that significantly place the male adolescent in detention at risk for STDs: multiple sexual partners, inconsistent condom use, and the quantity of alcohol consumed per week. CONCLUSION: Youth in detention place themselves at risk for STDs including HIV because of their risky sexual behavior and drug use. Addressing alcohol use and barriers to condom use appear to be essential components of any STD prevention program targeting this largely minority youth population.

Adolescent↗