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Biomedical subjects

M D Wilson

Publications and source records attributed to M D Wilson.

At least 19 recordsLinked to original sources
PubMed1998

Photodynamic therapy of U87 human glioma in nude rat using liposome-delivered photofrin.

BACKGROUND AND OBJECTIVE: Liposomes as photosensitizer carriers may enhance the photodynamic effect on tumors. STUDY DESIGN/MATERIALS AND METHODS: To test this hypothesis, we treated U87 human glioma in rat brain with photodynamic therapy (PDT) using Photofrin encapsulated in a liposome carrier or Photofrin in dextrose. Nontumored brain was also treated and Photofrin content ratios were measured in tumor and nontumored brain. RESULTS: PDT using the liposome encapsulated photosensitizer significantly increased tumor destruction compared to PDT with Photofrin in dextrose (P = 0.007), whereas no difference in tissue damage was detected in nontumored brain with or without liposome carrier. Photofrin uptake was also significantly elevated in the liposome vehicle group compared to the dextrose (P < 0.05) group. CONCLUSIONS: Our data suggest that Photofrin encapsulated in a liposome may enhance the PDT treatment of human brain tumors.

Animals↗
PubMed1998

Distribution of the Simulium damnosum complex on Bioko island, Equatorial Guinea, and the potential for onchocerciasis elimination by vector eradication.

Onchocerciasis is endemic on the island of Bioko, Equatorial Guinea, where it is transmitted by the 'Bioko form' of the Simulium damnosum complex, a cytospecies unique to the island. To determine the distribution of vector breeding, three dry season and two wet season expeditions were made in 1989, 1996 and 1997, and 226 of the island's 247 rivers (91.5%) were visited. Of these 226 rivers, 130 (58%) were flowing during the dry season, forty-five (20%) supported aquatic stages of Simuliidae of any species and twenty-five (11%) contained larvae or pupae of the S. damnosum complex. The twenty-one rivers not prospected were in the mountainous south of the island, where an additional seventeen rivers were reached but not satisfactorily prospected. Of these thirty-eight rivers, twenty-nine were considered highly likely to support vector breeding, bringing the total number of rivers which could harbour the vector during the dry season to fifty-four (21.9% of the island's total). Breeding was believed to be limited to river stretches below 1000 m altitude, and during the dry season the total length of those stretches which could support breeding on Bioko was estimated to be 1020 km. A combination of factors, including low river discharges during the dry season, the relatively low water temperature on Bioko, the suitability of limited stretches of most rivers as vector breeding sites and the close proximity of many rivers within a small geographical area, render the vector vulnerable to eradication by aerial treatment of rivers with insecticide. The isolation of the Bioko form of the S. damnosum complex suggests that reinvasion following treatment would be unlikely, and eradication of the vector might be achieved by a dry season larviciding programme in one or two years.

Altitude↗
PubMed1998

Dietary monounsaturated fatty acids promote aortic atherosclerosis in LDL receptor-null, human ApoB100-overexpressing transgenic mice.

In mice with genetically engineered high levels of plasma low density lipoprotein (LDL), we tested the hypothesis that an increase in the dietary content of monounsaturated fatty acids but not of polyunsaturated fatty acids would promote atherosclerosis. The mouse model used was an LDL receptor-null, human apoB100-overexpressing strain. Six experimental groups of 19 to 38 mice of both sexes were established when the animals had reached 8 weeks of age. For the next 16 weeks, individual groups were fed either a commercial diet or prepared diets including fat as 10% of energy, with 5 different fatty acid enrichment patterns including the following: saturated (sat), cis and trans monounsaturated (mono), and n-3 and n-6 polyunsaturated (poly). Highly significant differences (ANOVA, P<0. 0001) in LDL cholesterol (in mg/dL) were found, with the rank order at 16 weeks being trans mono (mean, 1390)>sat (922)=cis mono (869)=n-6 poly (868)>n-3 poly (652)>commercial diet (526). Significant elevations in very low density lipoprotein cholesterol were also found in the trans and cis mono and sat groups, and triacylglycerol concentrations were also elevated in all groups. High density lipoprotein cholesterol concentrations were consistently low (20 to 50 mg/dL) in all groups. Highly significant differences (ANOVA, P<0.0001) in atherosclerosis, quantified by measurement of aortic cholesteryl ester concentration (mg/g protein) among dietary fatty acid groups were found, with the order being trans mono (mean, 50.4)>sat (35.6)=cis mono (34.6)>n-6 poly (18. 3)=n-3 poly (9.7)=commercial diet (7.8). Therefore, in this mouse model of hypercholesterolemia, dietary cis or trans monounsaturated fat did not protect against atherosclerosis development, whereas aortic atherosclerosis in either of the polyunsaturated fat groups was significantly less than in the saturated fat group.

Analysis of Variance↗
PubMed1997

Residents' self-assessed skills in providing sexuality-related care to teenagers.

OBJECTIVES: To assess pediatric residents' self-reported skills and satisfaction with providing sexuality-related health care to teenagers and to examine differences by resident and patient gender. DESIGN: Cross-sectional survey. PARTICIPANTS: Forty second-year (PGY2) and 17 third-year (PGY3) pediatric residents at one training program who completed a self-administered questionnaire. MAIN OUTCOME MEASURES: Residents rated their skills with taking a history from, performing a physical examination on, developing a diagnosis for, and counseling both male and female teenagers. Skills with providing health care to male and female teenagers were assessed separately. Scales were constructed for skills with performing a physical examination and providing a diagnosis and counseling. Residents also rated their satisfaction with providing health care to male and female teenagers. Skills and satisfaction with providing health care to male vs female teenagers were analyzed. RESULTS: Female residents rated their skills with providing health care to male teenagers significantly lower than their skills with providing health care to female teenagers as follows: taking a history of pubertal development (PGY2, P = .001; PGY3, P = .02), taking a sexual history (PGY2, P = .004), asking about sexual preference (PGY2, P = .02), examination and diagnosis scale (PGY2, P < .001; PGY3, P = .008), and counseling scale (PGY2, P = .003). For male residents, there were no significant differences in skills with providing health care to male vs female teenagers. Second-year, but not third-year, female residents reported significantly lower (P < .005) satisfaction with providing health care to male vs female teenagers. CONCLUSIONS: Among female residents, discrepancies were found when comparing self-assessed competencies and, for PGY2 residents, level of satisfaction with providing health care to male vs female patients. If other research confirms these findings, educational interventions related to sexuality-related health care for teenagers should be designed with consideration to gender-specific learner needs.

Adolescent↗
PubMed1996

Depressive symptoms, stress, and social support in pregnant and postpartum adolescents.

OBJECTIVE: To assess prospectively the incidence and course of depressive symptoms among pregnant and postpartum adolescents and explore the roles of stress and social support as influencing factors. METHODS: Pregnant teenagers attending a comprehensive adolescent pregnancy and parenting program were enrolled during their third trimester of pregnancy and followed up through 4 months post partum. Depressive symptoms and social support were measured with validated, self-administered instruments during the third trimester and at 2 and 4 months post partum. Stress was measured during the prenatal and postpartum periods. RESULTS: Study participants (N=125) were predominantly black (93%), and wee aged 12 to 18 years. Completed assessments were obtained from 114 subjects at 2 months post partum and 108 at 4 months. Forty-two percent had significant depressive symptoms in the third trimester, with 36% and 32% having scores that indicated depression at 2 and 4 months post partum. Stress levels increased significantly from the third trimester to the postpartum period (P < .01) and were positively associated with depressive symptoms. Receiving social support from the adolescent's mother or the infant's father, especially in the postpartum period, was significantly associated with lower rates of depression. Reporting conflict with the infant's father was strongly associated with increased rates of depressive symptoms. CONCLUSIONS: Results indicate that depressive symptoms are common among pregnant teenagers and postpartum adolescents. Stress and social support appear to be important mediators. Identifying those teenagers with high stress and conflict and low levels of support will help identify those who are at particular risk for depressive symptoms.

Adolescent↗
PubMed1996

Emergency department visits and hospitalizations for respiratory disease on the island of Hawaii, 1981 to 1991.

This study examined trends in and patterns of emergency department visits and hospitalizations for respiratory disease on the island of Hawaii from 1981 to 1991. We found that emergency department visit rates and hospitalization rates for both asthma and COPD for 1987 to 1991 increased in all regions of the island in comparison with such rates for 1981 to 1986. Rates of emergency department visits and hospitalizations for chronic obstructive pulmonary disease or COPD, but not asthma, were significantly higher in the high-exposure Kona side of the island than in the intermittent-exposure Hilo side of the island during 1983 and 1988 to 1990. We also found that during the weeks that winds were from the west, blowing volcanic air pollution toward Hilo, emergency department visits for asthma increased 15%. Some of the results of our study support the hypothesis that volcanic air pollution affects respiratory health on the island of Hawaii, while other results do not. Any future studies should include measurements of air pollutant levels.

Adolescent↗
PubMed1995

Adolescent medicine.

In a survey of children and adolescents, one fourth of respondents reported having experienced an assault or abuse in the previous year. Violence is not restricted to inner cities. Marijuana use among eighth graders has more than doubled since 1991.

Adolescent↗
PubMed1995

Outcomes of adolescents using levonorgestrel implants vs oral contraceptives or other contraceptive methods.

OBJECTIVE: To compare outcomes among adolescents who use levonorgestrel implants, oral contraceptives, or other methods of birth control. DESIGN: Prospective, longitudinal study of 166 females who were followed up for 6 months. Fifty-four used implants, 64 used oral contraceptives, and 48 used condoms alone or with spermicide, or no contraceptive. Outcomes were measured by patient interview and medical chart review. SETTING: Inner-city, hospital-based adolescent and teenaged mother and baby clinic between April 1, 1992, and May 31, 1993. PARTICIPANTS: Sexually active 12- to 18-year-old females at least 1 year postmenarche who had no contraindications to use of hormonal contraceptives. MAIN OUTCOME MEASURES: Sexual activity, pregnancy rates, condom use, incidence of sexually transmitted disease, patient satisfaction continuation rates, and side effects. RESULTS: Despite similar reports of sexual activity, one subject who used the implant (2%) vs 13 subjects who used oral contraceptives (20%), and eight subjects who used other methods (17%) became pregnant (chi 2, P < .50). Condom use did not differ among groups (chi 2, P > .60). Overall, 30% of subjects contracted a new sexually transmitted disease; rates did not differ by method (chi 2, P = .92). Implant users were more likely than oral contraceptive users to continue their method (87% vs 50%; chi 2, P < .001) despite similar satisfaction scores (one-way analysis of variance, P = .52). Implant users were more likely to experience irregular menses, mood swings, acne, and hair loss (chi 2, P < .05). CONCLUSIONS: In this population, the levonorgestrel implant is an effective method of pregnancy prevention and is associated with high satisfaction and continuation rates at 6 months. Implant users are not at greater risk than others for sexually transmitted disease. Health care providers should continue to stress the use of barrier methods to all sexually active adolescents.

Adolescent↗
PubMed1995

Association between postpartum substance use and depressive symptoms, stress, and social support in adolescent mothers.

OBJECTIVE: Substance use by pregnant teenagers is an important public health problem, but published data on alcohol and illicit drug use by parenting teenagers are virtually nonexistent. This study determined the prevalence of alcohol and drug use in adolescent mothers in the first 4 months postpartum and explored associated psychosocial characteristics. METHODS: Teenagers attending a comprehensive adolescent pregnancy and parenting program were enrolled consecutively during a routine third trimester prenatal visit. Alcohol use since delivery was determined by self-report at 4 months postpartum using an instrument developed for the 1984 Survey of Drug Abuse Among Maryland Adolescents. Illicit drug use was measured with anonymous quantitative urine drug screens at 2 and 4 months postpartum. Depressive symptoms, stress, and social support were assessed at 2 and 4 months postpartum using validated, self-administered instruments. Differences in demographic characteristics, peer group influences, and psychosocial variables between substance users and nonusers were evaluated. RESULTS: Participants (125/129 eligible) were predominantly African-American, mean age 16.3 years. Completed assessments were obtained from 110 at 2 months and 105 at 4 months postpartum. Forty-two percent screened positive for illicit drugs at a postpartum visit or reported using alcohol since delivering their baby and were classified as substance users. Thirty-one percent of subjects reported alcohol use since delivery. Marijuana was the most prevalent illicit drug (14%), followed by opiates (5%), and cocaine (4%). When substance users were compared with nonusers, 44% versus 24% scored depressed (P = .02), 62% versus 43% had high stress (P = .04), and 62% versus 44% reported a high need for social support (P = .07). Results of logistic regression, after controlling for age, indicated that illicit substance and/or alcohol use was 3.3 times greater for those who were depressed, 2.8 times greater if they reported friends' using illicit drugs, and 6.7 times greater if the adolescent reported smoking cigarettes since delivery. CONCLUSIONS: This study indicates that alcohol and drug use are common among this sample of postpartum teenage mothers and that depression, stress, high support need, and peer group drug use are associated factors. Although this study cannot determine whether depression and stress precede or result from use of substances, attention to these factors appears warranted in the care of adolescent mothers.

Adolescent↗
PubMed1994

Obstructive sleep apnea, control of ventilation, and anesthesia in children.

Pathologic disturbances in breathing in children become clinically apparent in the syndrome of obstructive sleep apnea. The surgical approach to this syndrome is often removal of hypertrophied tonsils and adenoids. The preoperative, operative, and postoperative concerns with special attention to the role of anesthesia are reviewed.

Adenoidectomy↗
PubMed1994

Hypertension: are beta-blockers and diuretics appropriate first-line therapies?

OBJECTIVE: To review the existing data on the use of diuretics or beta-blockers as first-line therapy for the treatment of mild to moderate hypertension, and to examine the issues surrounding the impact of these classes as well as the angiotensin-converting enzyme (ACE) inhibitors, calcium-channel blockers (CCBs), alpha-blockers, and alpha-beta-blockers on cardiovascular risk factors and cardiovascular morbidity and mortality. DATA SOURCES: A MEDLINE search of applicable articles on antihypertensive therapies and their impact on morbidity and mortality. In addition, a MEDLINE search of relevant articles regarding cardiovascular risk factors and the influence of the various antihypertensive therapies on these parameters. DATA SYNTHESIS: The literature was evaluated with regard to outcome. Trials examining the impact of antihypertensive pharmacotherapy, primarily with diuretics and beta-blockers, have shown them to decrease the incidence of stroke by 33-50 percent. However, their effect on coronary heart disease has been disappointing, showing only a 14 +/- 5 (mean +/- SD) percent decrease. Examination of numerous clinical trials assessing the impact of the various antihypertensive therapies on cardiovascular risk factors, including blood pressure, plasma lipids, diabetic control/insulin sensitivity, and left ventricular hypertrophy was done. The classes included beta-blockers, diuretics, alpha-blockers, ACE inhibitors, and CCBs; the results show a diversity of effect. Diuretics and beta-blockers tend to worsen cardiovascular risk status, whereas the alpha-blockers, ACE inhibitors, and CCBs all show a beneficial effect. CONCLUSIONS: Diuretics and beta-blockers can effectively reduce cerebrovascular morbidity and mortality, but have a limited effect on reducing cardiovascular disease, especially myocardial infarction. This may be explained, at least in part, by the negative, or lack of positive, effect on individual patients' overall cardiovascular risk status.

Adrenergic alpha-Antagonists↗
PubMed1994

Loss of heterozygosity and overexpression of the p53 gene in ovarian carcinoma.

Mutation and allelic loss of the p53 gene have been demonstrated in a variety of human cancers. In this study, DNA was extracted from formalin-fixed paraffin sections of ovarian carcinoma from 33 patients informative for a restriction fragment length polymorphism (RFLP) for BstU 1 within the 4th exon of the p53 gene. Allelic loss of p53 as indicated by loss of heterozygosity for this RFLP was demonstrated in 16/33 cases (48%). Because immunoreactivity for p53 correlates closely with the presence of mutation in the p53 gene, we performed immunohistochemical staining with the monoclonal antibody PAb1801. Diffuse nuclear p53 immunoreactivity was observed in 16 of the 33 (48%) informative cases used for loss of heterozygosity analysis (37/80 (46%) cases of ovarian carcinoma overall). A significant correlation (Fisher's exact test, P = 0.04) was observed between p53 overexpression and allelic loss. We found no evidence of association of p53 allelic loss or overexpression with advanced stage or other clinical or pathologic prognostic parameters. We conclude that mutation and allelic loss of p53 are common and probably related events in the development of ovarian carcinoma. This study demonstrates the use of paraffin sections in the analysis of p53 alterations in neoplasia.

Base Sequence↗
PubMed1994

Attitudes, knowledge, and behavior regarding condom use in urban black adolescent males.

This study was conducted to determine male adolescent behavior, attitudes, and knowledge concerning the use of condoms. Subjects were 241 sexually active black adolescent males attending an inner-city adolescent medicine clinic who were surveyed using a structured interview technique. Factors associated with condom use included higher grade level, > or = 2 sexual partners in the past six months, communication about contraception with sexual partner(s), desire for sexually transmitted disease (STD) prevention when contracepting, and parental suggestion to use condoms. Variables not associated with condom use included older age, minimal level of knowledge about condom use, history of having impregnated a partner or of having contracted an STD, desire for pregnancy prevention, suggestion by friends to use condoms, or partner dissatisfaction with condoms. Using multivariate logistic regression analysis, the following variables in combination were able to correctly classify respondents as condom users or nonusers in 74% of cases: higher knowledge score, reported communication about contraception with one's partner(s), > or = 2 partners in the past six months, and higher socioeconomic status. These findings suggest that, for the study population, interventions directed toward improving knowledge about condoms, school achievement, and communication with parents and partners may be effective in increasing condom use.

Adolescent↗