Search PubMed⌕ Search

Biomedical subjects

M D Wilson

Publications and source records attributed to M D Wilson.

At least 37 records · Page 2Linked to original sources
PubMed2000

Consumption of soy protein reduces cholesterol absorption compared to casein protein alone or supplemented with an isoflavone extract or conjugated equine estrogen in ovariectomized cynomolgus monkeys.

Dietary intake of soy protein is associated with reductions in plasma cholesterol. Isoflavones are thought to be active components of soy and responsible for the beneficial effects because of their structural similarities to estrogen. The purposes of this study were to determine if i) soy protein or a semipurified soy extract, rich in isoflavones, is responsible for improving the lipid profile and ii) altered intestinal cholesterol metabolism is one mechanism for hypocholesterolemic effects. Ovariectomized adult female cynomolgus monkeys (40) were assigned to groups fed diets containing i) casein-lactalbumin (CAS) ii) intact soy protein (SOY), iii) CAS plus an isoflavone-rich semipurified soy extract similar in isoflavone content as SOY (ISO) or iv) CAS plus conjugated equine estrogen (CEE) for 20 wk. Cholesterol absorption was determined using the fecal isotope ratio method. Bile acid excretion was measured using the 3alpha-hydroxysteroid dehydrogenase assay. The SOY group had significantly lower total- and VLDL + LDL-cholesterol compared to the other three groups and significantly higher HDL-cholesterol compared to the CAS and CEE groups. Cholesterol absorption was significantly lower in the SOY group compared to the other groups, but bile acid excretion was not significantly affected. The hypocholesterolemic effect of soy protein appears to be mediated in part by decreased cholesterol absorption. The semipurified soy extract, rich in isoflavones, added to casein protein did not have lipid-lowering effects. Other components of soy such as saponins, phytic acid or the amino acid composition may be involved in the hypocholesterolemic effects seen in this study.

Animals↗
PubMed2000

Defining the atherogenicity of large and small lipoproteins containing apolipoprotein B100.

Apo-E-deficient apo-B100-only mice (APOE:(-/-)APOB:(100/100)) and LDL receptor-deficient apo-B100-only mice (LDLR:(-/-)APOB:(100/100)) have similar total plasma cholesterol levels, but nearly all of the plasma cholesterol in the former animals is packaged in VLDL particles, whereas, in the latter, plasma cholesterol is found in smaller LDL particles. We compared the apo-B100-containing lipoprotein populations in these mice to determine their relation to susceptibility to atherosclerosis. The median size of the apo-B100-containing lipoprotein particles in APOE:(-/-)APOB:(100/100) plasma was 53.4 nm versus only 22.1 nm in LDLR:(-/-)APOB:(100/100) plasma. The plasma levels of apo-B100 were three- to fourfold higher in LDLR:(-/-)APOB:(100/100) mice than in APOE:(-/-)APOB:(100/100) mice. After 40 weeks on a chow diet, the LDLR:(-/-)APOB:(100/100) mice had more extensive atherosclerotic lesions than APOE:(-/-)APOB:(100/100) mice. The aortic DNA synthesis rate and the aortic free and esterified cholesterol contents were also higher in the LDLR:(-/-)APOB:(100/100) mice. These findings challenge the notion that all non-HDL lipoproteins are equally atherogenic and suggest that at a given cholesterol level, large numbers of small apo-B100-containing lipoproteins are more atherogenic than lower numbers of large apo-B100-containing lipoproteins.

Animals↗
PubMed2000

Cytotaxonomic and molecular analysis of Simulium (Edwardsellum) damnosum sensu lato (Diptera: Simuliidae) from Abu Hamed, Sudan.

The northernmost focus for Onchocerca volvulus Leuckhart (Nematoda: Onchocercidae), the causative agent of human onchocerciasis, is found along the Nile near the town of Abu Hamed in Sudan. The vector for O. volvulus at this focus is a single monomorphic population of Simulium (Edwardsellum) damnosum Theobald. This black fly population is limited to a small area between the fourth and fifth cataracts of the Nile River that is isolated geographically from all other populations of S. damnosum sensu lato. Phylogenies produced from cytological analyses and sequence data derived from the NADH dehydrogenase subunit 4 and 16S rRNA genes indicate that Abu Hamed black flies are similar to, but distinct from, the savanna-dwelling sibling species of S. damnosum s.l., Simulium (Edwardsellum) damnosum sensu strictu Theobald, and S. (Edwardsellum) sirbanum Vajime & Dunbar. The DNA sequence and the cytological data support the hypothesis that the black fly population present in Abu Hamed may represent a new sibling species of S. damnosum s.l. We propose that this population be informally designated as the hamedense form of the Simulium damnosum complex.

Animals↗
PubMed2000

Correlative experimental animal and human clinical retrieval evaluations of hydroxyapatite (HA)-coated and non-coated implants in orthopaedics and dentistry.

Retrieval analyses disclosed in vivo dissociation of HA in orthopaedic acetabular components, but excellent bone ingrowth into intact HA coatings on dental retrievals. Initial healing and the bone interface between HA-coated and non-coated implants in the posterior maxilla (Mx) and mandible (Md) was assessed in an animal model using light microscopy (LM), including confocal (CM) and Nomarski (NM) microscopy. Seventy-two implants (36 HA-coated; 36 non-coated) were placed into jaws of six dogs; half after extraction, half after 3 months healing. Animals were euthanized 3 months postimplantation. All implants osseointegrated; however, preliminary morphometry showed higher BCL for HA-coated (51%) than non-coated implants (44%) in the Mx (p < 0.05). BCL for HA-coated Md implants was not significantly higher (64%) than non-coated implants (62%). Bone closely apposed both implant types; however, LM suggested a more intimate association with HA coatings. Serial sections disclosed a reddish coating on the HA, possibly analogous to oral tissue proteoglycans, which was not visible with non-coated implants. This material was continuous with similar material coating endosteum, osteoid regions, and osteocyte (Os) lacunae close to the implant. An interdigitating canaliculi network allowed communication between interfacial Os and Os deeper within the bone. Data suggest HA offers enhanced initial bone fixation in the Mx, and that adequate bone exists for non-coated implant stability in the Md. No HA dissociation was seen with implants in the animal study, which was consistent with retrieved human HA dental implants.

Acetabulum↗
PubMed2000

Children's mental health: recommendations for research, practice and policy.

A recent study documented a large increase in prescriptions of stimulants and antidepressants among preschoolers, and has prompted public and professional concern about the effects of mood-altering drugs on young children. In response, the White House announced a broad initiative on children's mental health, including more government money for research, new labels on drugs for pediatric use, educational materials for parents, and a fall White House conference. To place these events in their larger context, this Issue Brief summarizes the findings of the Children's Mental Health Alliance Project, which conducted a multidisciplinary consensus conference in November 1998 followed by a year-long dialogue with clinicians, researchers, and families.

Child↗
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↗