Biomedical subjects

J T Wright

Publications and source records attributed to J T Wright.

At least 109 records · Page 6Linked to original sources

PubMed1993

Enamel ultrastructure and protein content in X-linked amelogenesis imperfecta.

X-linked amelogenesis imperfecta has been proven in a number of families to be linked to or involve a variety of mutations in the X chromosome amelogenin gene. The purpose of this study was to characterize the enamel ultrastructure and enamel protein in a kindred affected by X-linked amelogenesis imperfecta. Exfoliated primary teeth were obtained from two related persons (one male, one female) who had X-linked amelogenesis imperfecta with marked hypoplasia. Normal enamel (age and sex matched) was used as the control for all analyses. The teeth were evaluated using light microscopy, scanning electron microscopy, and microradiography. The enamel of the heterozygous female was hypoplastic and rough with marked surface depressions. Enamel beneath these depressions was poorly organized and lacked a prismatic structure. The affected male had very thin enamel (approximately 40 microns) that also lacked an organized structure. Enamel protein from the teeth of the heterozygous female and the control was characterized using amino acid analysis. The protein content of the enamel of the female with amelogenesis imperfecta was 0.40% (N = 1) whereas the control enamel ranged from 0.17% to 0.45% (N = 4; mean = 0.34%). This study indicates that although the enamel in both the male and female with X-linked amelogenesis imperfecta displayed marked structural abnormalities the enamel protein was similar in quantity and amino acid composition for normal and X-linked amelogenesis imperfecta (female) enamel.(ABSTRACT TRUNCATED AT 250 WORDS)

Amelogenesis Imperfecta↗

PubMed1993

Oral complications in children with cancer.

Oral complications during cancer therapy are a common source of discomfort and a potential source of systemic infection. We report the results of a 2 1/2-year prospective follow-up study on the incidence of oral complications in 214 pediatric patients with cancer. Overall, the incidence of ulcers in these patients ranked highest followed by gingivitis. Children with sarcomas had more ulcers (p = 0.03) and Candida infections (p = 0.03) than those with leukemia. The rate of gingivitis among patients with leukemia was five times higher than in patients with sarcoma (p = 0.02). Candida infections in children with solid tumors occurred four times more often than in patients with leukemia (p = 0.02). This study shows that oral complications are a frequent cause of morbidity in children with cancers and are more common in some cancers than in others. Oral complications may be prevented or diminished in severity by identifying the risk groups and developing preventive and treatment strategies.

Adolescent↗

PubMed1993

Perindopril as monotherapy in hypertension: a multicenter comparison of two dosing regimens. The Perindopril Study Group.

Perindopril erbumine, a new long-acting, non-sulfhydryl-containing angiotensin converting enzyme inhibitor, was evaluated in 289 patients with hypertension in a 16-week, double-blind, placebo-controlled dose-ranging study. After 4 weeks of single-blind placebo treatment, patients with supine diastolic arterial pressures from 95 to 114 mm Hg were randomized to receive placebo, 4 mg perindopril once daily, or 2 mg perindopril twice daily. The daily dose of perindopril was increased by 4 mg every 4 weeks to a maximum of 16 mg per day. Mean decreases in systolic and diastolic arterial pressure were greater with perindopril than with placebo (p < 0.05). The dose-response curve flattened after 8 mg per day, and there was no difference in arterial pressure reduction or in the percentage of responders between once- and twice-daily administration of perindopril. Adverse reactions with perindopril were generally mild and, with the exception of cough, were similar with placebo. The findings of this study indicate that perindopril is effective, well tolerated, and suitable for once-daily administration for the treatment of hypertension.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1993

Intracytoplasmic retention of type VII collagen and dominant dystrophic epidermolysis bullosa: reversal of defect following cessation of or marked improvement in disease activity.

It has been recently shown that the presence of perinuclear "stellate bodies" within the epidermis in patients with a form of dominant dystrophic epidermolysis bullosa named "transient bullous dermolysis of the newborn" corresponds to collections of type VII collagen. To determine the temporal relationship of this unique immunohistochemical defect with course of clinical disease activity, we have longitudinally studied the expression of two epitopes of type VII collagen (LH 7:2; L3d) in nine patients in four such kindreds by immunofluorescence and immunoelectron microscopic technique. In every infant so studied at the time of active blistering, type VII collagen was detectable primarily within basilar and, to a lesser extent, suprabasilar keratinocytes. In contrast, type VII collagen was detectable solely in linear array along the dermoepidermal junction in skin from each patient following complete cessation or at least marked diminution of visible clinical disease activity. These findings support the hypothesis that the temporary mechanical fragility and blistering of the skin in infants with this rare subset of dominant dystrophic epidermolysis bullosa reflect the presence of reduced amounts of type VII collagen along the dermoepidermal junction, and that this diminution may be the result of either a delay in transport and integration of type VII collagen from basilar keratinocytes into the skin basement membrane or excessive phagocytosis of type VII collagen.

Adult↗

PubMed1993

In vitro differentiation of preadipocytes from hypophysectomized pig fetuses.

Hypophysectomy of the pig fetus alters the number of fat cells and fat cell clusters as well as lipogenic enzyme activities in tissues compared with littermate controls. The objective of the present study was to determine whether the altered endocrine environment in vivo affected subsequent development and differentiation of preadipocytes in vitro. Hypophysectomy was performed in utero at 70 d of gestation. At 105 d of gestation, stromal-vascular cells from dorsal subcutaneous adipose tissues were cultured in several differentiation media. Overall, stromal-vascular cultures from hypophysectomized fetuses contained fewer fat cell clusters and concomitantly lower glycerol-3-phosphate dehydrogenase specific enzyme activity than did cultures from littermate controls. Fluorescence-activated flow cytometry using a monoclonal anti-adipocyte/preadipocyte antibody designated AD-1 revealed that hypophysectomy also reduced the proportion of cells expressing the AD-1 cell surface antigen. These results demonstrated that effects of fetal hypophysectomy on cells from adipose tissues are maintained and measurable in culture. In addition, one of the consequences of fetal hypophysectomy may be diminution in the relative proportion of adipocyte precursors.

Adipose Tissue↗

PubMed1993

Effect of hydrochlorothiazide, enalapril, and propranolol on quality of life and cognitive and motor function in hypertensive patients.

The effect of hydrochlorothiazide, propranolol, and enalapril on cognitive and motor function and quality of life (QOL) in hypertensive patients was studied. Patients > or = 55 years of age with asymptomatic essential hypertension were included in a randomized, double-blind, placebo-controlled, crossover study. Subjects discontinued their previous antihypertensive agents and started hydrochlorothiazide 25 mg, extended-release propranolol hydrochloride 120 mg, enalapril maleate 10 mg, or placebo. One capsule was taken for three days and then the dosage was doubled for the remainder of a four-week period. Subsequent crossover treatments were begun without a washout period. In each treatment phase, a battery of psychometric tests was used to assess cognitive and motor function and quality of life; all tests but one were self-administered via computer terminal. Pulse rate and blood pressure were recorded, and compliance was monitored by capsule count. Sixteen of 30 patients interviewed completed the trials; one additional patient was evaluated after receiving all treatments except hydrochlorothiazide. Mean +/- S.D. age of the subjects was 66 +/- 6.1 years; 10 were black and 7 white; 9 were men. Except for the hydrochlorothiazide group, blood pressure in the active treatment groups did not differ significantly from placebo; hydrochlorothiazide significantly reduced systolic but not diastolic blood pressure compared with placebo. Compared with placebo, hydrochlorothiazide was associated with fewer incorrect responses in a test of complex reaction time and with greater discriminant reaction time response rates; otherwise, no difference between groups was noted in cognitive or motor performance. There were no significant differences between active treatments and placebo on individual QOL measures.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1993

Comparison of the efficacy and metabolic effects of nicardipine and hydrochlorothiazide in hypertensive black men and women.

A double-blind, randomised, parallel study compared the BP and metabolic responses in black hypertensive patients following monotherapy with nicardipine or hydrochlorothiazide (HCTZ). Following a single-blind placebo wash-out period of 1-4 weeks, the study drug, nicardipine 20-40 mg three times daily or HCTZ 25-100 mg four times daily, was administered in a double-blind fashion for 12 weeks. Doses were titrated to control sitting DBP (< or = 90 mmHg). Both drugs were effective in reducing sitting SBP and DBP as compared with baseline values (nicardipine: 152.5 +/- 1.6/102.0 +/- 0.6, HCTZ: 152.5 +/- 1.5/101.4 +/- 0.5 mmHg). DBP responses (reduction from baseline; nicardipine: -10.9, HCTZ: -12.7 mmHg), and the percentage of patients achieving a response < or = 90 mmHg (nicardipine: 54%, HCTZ: 63%) to the two drugs were similar. Although SBPs at baseline and endpoint (137.3 +/- 1.6 on nicardipine and 132.1 +/- 1.4 mmHg on HCTZ), and the percentage of patients achieving a response < or = 140 mmHg (nicardipine: 70%, HCTZ: 79%), were comparable between the two treatments, the SBP reduction with HCTZ was statistically greater (P = 0.026). A comparison of the metabolic responses in the two treatment groups showed significant differences. Nicardipine caused no significant changes in blood chemistry, whereas HCTZ caused statistically significant decreases (P < 0.001) in sodium and potassium and increases (P < or = 0.01) in glucose, BUN, creatinine, uric acid, cholesterol and LDL compared with baseline. In 12.7% of the patients in the HCTZ group, serum potassium dropped to levels < 3.5 meq/l, which occurred in only 1.4% of the patients who used nicardipine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Lack of effect of topical iodostearic acid on cervical intraepithelial neoplasia II-III.

Stearic and iodostearic acid inhibit growth of a cervical carcinoma cell line in vitro. This study was performed to determine if iodostearic acid would induce regression of cervical intraepithelial neoplasia (CIN). Women with histologically-proven CIN II or III were randomised into two groups. Those in the first group were given pessaries composed of iodostearic acid in polyethylene glycol (PEG) base. Women in the second group were given pessaries containing only the PEG base. One pessary was inserted into the vagina nightly for 30 nights, and each woman then had the CIN lesion removed by CO2 laser cone excision. There was no difference in the histology of the cone biopsies between the groups, demonstrating that this regime of iodostearic acid has no useful role in the treatment of CIN II-III.

Adult↗

PubMed1992

Impact of an electronic medication compliance aid on long-term blood pressure control.

A two-phase study was conducted to assess the effect of an electronic medication compliance aid on hypertension control and pharmaceutical compliance in ambulatory patients. In Phase I (12 weeks), 36 patients were randomly assigned to a medication vial equipped with a cap containing a digital timepiece that displays the last time the cap was removed. The control group included 34 patients randomly assigned to a standard medication vial. Subjects using the timepiece cap showed an average compliance rate of 95.1%, an average decrease in systolic pressure of 7.6 mm Hg (P = .006), and an average decrease in diastolic pressure of 8.8 mm Hg (P less than .001). Controls had an average compliance rate of 78% and decreases of 2.8 mm Hg and 0.2 mm Hg in systolic and diastolic pressures, respectively. Phase II (12 weeks) combined use of the timepiece cap with other compliance aids: a pocket-size card for recording blood pressure and a blood pressure cuff for self-monitoring. Patients using the timepiece cap and the card had an average compliance rate of 98.7% with mean decreases of 11 mm Hg in systolic pressure (P less than .01) and 7.64 Hg mm in diastolic pressure (P = .0001). The combined use of the cap, the card, and the blood pressure cuff resulted in an average 100.2% compliance rate with mean decreases of 15 mm Hg (P = .0006) and 6.60 mm Hg (P = .0006) in systolic and diastolic pressures, respectively. Results of the two-phase study showed statistically significant increases in medication compliance associated with statistically and clinically significant reductions in blood pressure for all patients using the timepiece cap.

Aged↗

PubMed1992

Flow cytometric analysis of porcine preadipocytes.

In this report, conditions have been established for utilizing monoclonal antibodies and fluorescence activated flow cytometry in studying antigen expression by primary porcine stromal-vascular cells cultured under various conditions. Single cells were isolated from cultures maintained in DME/F12 medium containing 10% fetal bovine serum, 2% pig serum, and containing 2% pig serum and 10 nM dexamethasone supplemented with growth hormone (GH), tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-beta (TGF-beta). Flow cytometric analyses revealed that the proportion of cells expressing detectable levels of the AD-1 cells surface antigen was greater in cultures supplemented with 2% pig serum and 10 nM dexamethasone than in other media. In cultures, GH, TNF-alpha and TGF-beta each inhibited lipid deposition, whereas TNF-alpha and TGF-beta, but not GH, inhibited AD-1 antigen expression. Inhibition of lipid deposition as well as antigen expression by TNF-alpha and TGF-beta was reversible, but inhibition of cluster formation by GH was not reversed upon removal from cultures. In summary, differential effects of factors on surface antigen expression by preadipocytes are detectable by flow cytometry. Flow cytometric analysis using monoclonal antibodies produced against key developmentally regulated cell surface antigens is potentially a powerful analytical approach to the study of adipocyte development.

Adipose Tissue↗

PubMed1992

Practical pharmacokinetics of ventricular antiarrhythmic therapy.

An increasing number of antiarrhythmic agents have become available for the treatment of ventricular tachyarrhythmias. Appropriate application of pharmacokinetic principles is essential to determine dosage amount and frequency, particularly because of the life-threatening consequences of inadequate therapy. Therefore absorption, distribution, metabolism, and elimination of antiarrhythmic agents must be considered in their use. Although some may be given intramuscularly, antiarrhythmic drugs are usually administered either intravenously for rapid onset of action or orally during long-term therapy. Distribution of antiarrhythmic drugs may be influenced by physicochemical properties of the drug (i.e., protein binding) or by tissue blood flow. Drug interactions and half-life are also important considerations. Finally, the major routes of elimination of antiarrhythmics are hepatic metabolism and renal and biliary excretion. The pharmacokinetic profiles of drugs used for the treatment of ventricular tachyarrhythmia, all of which are types I and III antiarrhythmic agents, are discussed.

Anti-Arrhythmia Agents↗

PubMed1992

The Cleveland Veterans Affairs Medical Center firm system.

Hospital-based "firms" provide a means for combatting the fragmentation experienced by both patients and caregivers in the modern teaching hospital environment. A "firm" is an academic group practice that includes attending physicians, physician trainees, nurses, other staff, and patients. Each person's relationship with a firm lasts throughout his or her association with a particular institution. This article describes the firm system that was recently implemented on the Medical Service of the Cleveland VAMC. This system incorporates both inpatient and outpatient general medical services and provides for unbiased assignment of patients, physicians, and nurses.

Adult↗

PubMed1992

Heterogeneity of CYP3A isoforms metabolizing erythromycin and cortisol.

The N-demethylation of erythromycin and 6 beta-hydroxylation of cortisol are both functions of the glucocorticoid-inducible CYP3A in human liver microsomes. To determine whether 6 beta-hydroxylation and erythromycin N-demethylation are catalyzed by similar or distinct CYP3A isoforms, erythromycin N-demethylase activity, as reflected by the recently described 14[C]-erythromycin breath test, was compared with urinary 6 beta-hydroxycortisol/cortisol ratios, a measure of cortisol 6 beta-hydroxylase activity, in nine patients. Erythromycin N-demethylation varied fourfold and 6 beta-hydroxycortisol/cortisol ratios varied sevenfold among the subjects; no correlation was found between these activities (r2 = 0.065). New noninvasive tests of CYP3A strongly suggest cortisol 6 beta-hydroxylation and erythromycin N-demethylation are performed by distinct CYP3A isoforms.

Aged↗

PubMed1992

Effect of conventional dental restorative treatment on bacteria in saliva.

Dental caries results from the dissolution of mineralized dental tissues by the metabolic by-products of oral bacteria colonizing the surface of teeth. The principal modality for dealing with this infectious process is through restorative treatment which removes the pathologic tissue and replaces it with a variety of inert materials. The purpose of this study was to evaluate the effect of traditional restorative treatment on select oral bacterial populations. Fifty-two females demonstrating high levels of mutans streptococci (greater than or equal to 2.5 x 10(4) colony forming units (cfu) per ml saliva) with no more than four missing posterior teeth were recruited for this study. Salivary levels of mutans streptococci, lactobacilli, total streptococci, and total cultivable bacteria were evaluated before, during, and after restorative treatment. Initial DMFS scores were established by two standardized examiners using bitewing radiographs and clinical examination, which was conducted under optimal conditions. All restorative treatment was completed by faculty members of the University of Alabama School of Dentistry using treatment plans developed by the DMFS examiners. The participants received a mean of 16.4 restored surfaces, which resulted in significant reductions of all the bacterial populations tested. All microbial populations monitored were predicted to return to their baseline levels within 151 days after restorative treatment in 50% of the participants. This study shows that conventional restorative treatment results in a significant reduction of bacterial populations including those associated with the dental caries process, i.e., mutans streptococci and lactobacilli.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Enamel ultrastructure in pigmented hypomaturation amelogenesis imperfecta.

Hypomaturation amelogenesis imperfecta (AI) is a hereditary condition of enamel that is presumed to result from defects during the maturation stage of enamel development. This study characterized the enamel ultrastructure and enamel crystallite morphology, as well as the distribution of organic material in enamel affected with pigmented hypomaturation AI. Enamel exhibiting autosomal recessive pigmented hypomaturation AI was sectioned or fractured and examined using light microscopy, scanning electron microscopy and transmission electron microscopy. Enamel samples were treated with 30% NaOCl or 8 M urea to remove organic components and determine the effect of deproteinization on crystallite morphology. These were compared with untreated normal enamel samples. The enamel crystallites in hypomaturation AI exhibited considerable variability in size and morphology. Examination of deproteinized tissue indicated that the AI crystallites had a thick coating, presumably of organic or partially mineralized material, which was not visible in normal enamel. The results of this investigation provide further evidence that hypomaturation AI is associated with the retention of organic material that is most probably enamel protein. Enamel protein retention is likely to be involved in the inhibition of normal crystallite growth resulting in the morphological crystallite abnormalities associated with this disorder.

Amelogenesis Imperfecta↗

PubMed1992

Destructive periodontal disease in healthy children.

This study determined the prevalence of destructive periodontal disease affecting the deciduous dentition among otherwise healthy subjects, who were diagnosed with juvenile periodontitis (JP) in their permanent dentitions. There were 4,757 subjects in this retrospective, cross-sectional study. Diagnosis of JP was based on age (< or = 15 years), negative medical history, and radiographic evidence of arc-shaped alveolar bone loss. The study population was one-third white and two-thirds black and the male/female ratio was 1:1, reflecting the general patient population. The prevalence among whites was 0.3%, with a female/male ratio 4:1; whereas among blacks the prevalence was 1.5%, with a female/male ratio approximately 1:1. Among the black JP subjects with radiographs of the mixed dentition, 85.7% presented evidence of bone loss, and of those with radiographs of the deciduous dentition, 71.4% had discernible alveolar bone loss. This study suggests that JP is much more prevalent in blacks and that it does indeed occur in the prepubertal years affecting the deciduous as well as the permanent dentitions in otherwise healthy children. These data imply the importance of including a periodontal evaluation in the examination of children, using the periodontal probe and radiographs sufficient to adequately view the alveolar bone.

Adolescent↗

PubMed1992

Characteristics of smokeless tobacco use among high school football players as related to type of smokeless tobacco and period of use.

The present study was conducted to assess differences in the behavioral and demographic characteristics of snuff (dip) users as compared to users of chewing tobacco. High School football players (1116) were surveyed concerning their use and perceptions of smokeless tobacco. Adolescent athletes who tried smokeless tobacco were more likely to be white, to use cigarettes, alcohol, and cigars and to have family users than those who never tried. Initial use was highest before the age of fourteen years and was influenced by friends, curiosity and family. Dippers tended to initiate use because of friends, while chewers started because of family users. Users of both dip and chew started primarily because of curiosity. Users of both were more likely to consume greater amounts to alcohol and cigarettes and to smoke cigars and pipes. It appears that the longer smokeless tobacco is consumed, the more likely both dip and chew will be used. Users of smokeless tobacco for more than two years tended to consume more of the product each week, used it for more hours/day, initiated use at an earlier age, and used it more often at school and work than those using it for less than two years. Use of cigars/pipes, consumption of alcohol, and quantity of cigarette consumption increased significantly with longer duration of smokeless tobacco use. Intervention and prevention programs would be helped by understanding differences between users of various smokeless tobacco products and differences related to the duration of use. In addition, further analyses of smokeless tobacco users should study chewers, dippers, and users of both separately.

Adolescent↗

PubMed1992

Expression of transforming growth factor-beta (TGF-beta 1) and insulin-like growth factor II (IGF-II) messenger RNA in the developing subcutaneous tissue (SQ) of the fetal pig.

Studies (in situ hybridization) were performed on the developing subcutaneous tissue (SQ) of the pig fetus to determine sites of synthesis of TGF-beta 1 and IGF-II. Tissues from 50, 70, 90, 110-day-old pig fetuses and 7-day-old postnatal pigs were Bouin's fixed, paraffin embedded and hybridized with biotin labelled cDNA probes. The expression of TGF-beta 1 messenger RNA was detectable primarily in the dermis, hair follicle fat lobule, outer and inner SQ areas at all ages. Cells adjacent to adipocyte clusters and some small adipocytes were positive for TGF-beta 1. There was no positive hybridization of TGF-beta 1 probes in the developing muscle below the SQ. The expression of IGF-II was evident in the developing muscle below the SQ at 50 d and 70 d, and could be detected in the outer and inner SQ at 70 d. Much lower levels of IGF-II expression were observed in 90 and 110 d fetuses, but an increase in IGF-II expression was evident in the muscle of 7d postnatal pigs. Our results suggest that paracrine and autocrine regulatory systems may be operative for developing adipocytes (TGF-beta 1) and muscle (IGF-II), with specific areas and times of TGF-beta 1 and IGF-II expression being evident in developing pig SQ tissue.

Animals↗