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Biomedical subjects

M Van Horn

Publications and source records attributed to M Van Horn.

12 recordsLinked to original sources
PubMed2001

Identification and initial characterization of 5000 expressed sequenced tags (ESTs) each from adult human normal and osteoarthritic cartilage cDNA libraries.

OBJECTIVE: To prepare, sequence and analyse adult human cartilage cDNA libraries to study the gene expression pattern between normal and osteoarthritic cartilage. METHODS: Poly A(+)RNA from adult human normal and osteoarthritic articular cartilage was isolated and used to prepare cDNA libraries. Approximately 5000 ESTs from each library were sequenced and analysed using bioinformatic tools. The expression of select genes was confirmed by Northern blot and in situ hybridization analysis. RESULTS: Multiple gene families including several classical cartilage matrix protein encoding genes were identified. Approximately 28-40% of the genes sequenced from these libraries were novel, while half of the genes encoded known proteins and 4-6% of the genes encoded novel homologs of known proteins. Several known genes, whose expression has not been reported previously in cartilage, were also identified. We have confirmed the cartilage expression of three known (CTGF, CTGF-L and clusterin) and two novel homologs of known genes (PCPE-2 and Gal-Nac transferase) by Northern blot and in situ hybridization analysis. CONCLUSION: This is the first report of the preparation and sequencing of cDNA libraries from adult human normal and osteoarthritic articular cartilage. Further analysis of genes identified from these libraries may provide molecular targets for diagnosis and/or treatment of osteoarthritis (OA).

Adult↗
PubMed2001

Illness-related concerns of mothers of children with congenital heart disease.

OBJECTIVE: This study examined concerns expressed by mothers of children with congenital heart disease (CHD). The relationships among mothers' concerns, medical severity, and mother's emotional state were examined at two points in time. METHOD: Thirty-eight mothers of children with CHD aged 3 to 16 completed semistructured interviews and rating scales during hospitalization and 2 to 4 weeks after discharge. Mothers rated their distress about illness-related concerns, as well as their own depressed mood and anxiety. Mothers and two cardiologists rated the medical severity of each child's disease. RESULTS: Mothers' concerns were reliably grouped into five categories: medical prognosis, quality of life, psychosocial functioning, effects on family, and financial issues. During hospitalization, mothers were most concerned about medical prognosis. Distress about most concerns decreased postdischarge, as did mother's anxiety and depressed mood. Mothers' perceptions of medical severity were associated with distress about psychosocial issues postdischarge. Mother's anxiety was not associated with number of concerns reported, or with distress about those concerns. Maternal depressed mood was associated with fewer illness-related concerns, but greater distress about those concerns. CONCLUSIONS: Illness-related concerns can be meaningfully categorized and are not necessarily a function of disease severity or mother's emotional state. An awareness of common concerns will improve clinical care by enabling practitioners to anticipate and address concerns in a proactive way. The results may inform the development of supportive mental health interventions for families of children with CHD.

Adaptation, Psychological↗
PubMed1998

Dysphoric interpersonal schemata and preadolescents' sensitization to negative events.

Addresses the hypothesis that interpersonal schemata sensitize dysphoric youngsters to negative social information and contribute to the amplification of depressive symptoms. Sensitization was conceptualized as involving multiple components, including heightened anticipation, selective focus, and rapid information processing. Four studies with separate samples of preadolescents and early adolescents were conducted. Results from 3 laboratory-based studies indicated that depressed and dysphoric youngsters evince relatively negative interpersonal schemata, and that these schemata are related to the 3 components of sensitization. A short-term prospective study examined the hypothesis that dysphoric interpersonal schemata moderate the emotional impact of a normative social stressor, the transition to high school. Results indicated that youngsters who entered the transition with relatively negative schema experienced the transition as more stressful than youngsters with relatively positive schema, and that negative interpersonal schema amplified the effects of stress on depressive symptoms.

Adaptation, Psychological↗
PubMed1997

Dysphoria and children's processing of supportive interactions.

This study examined the processing of supportive interactions by dysphoric and nondysphoric preteens and early adolescents. Seventy-two youngsters between the ages of 10 and 13 evaluated the supportiveness and helpfulness of standardized, videotaped interactions between a distressed preadolescent and a maternal figure. The tape presentations varied in terms of the level of depicted maternal support and instructional condition (degree of self-reference). The results indicated that dysphoric youngsters evaluated both the supportiveness and helpfulness of interactions less positively than nondysphoric agemates. Group differences in support evaluations were most pronounced in the self-referenced condition. The level of depicted support did not affect processing differences. Dysphoric subjects reported lower levels of emotional support in prior relationships and a greater tendency to view supportive behavior as ingenuine than nondysphoric peers. Variation in prior support experiences accounted for group differences in the evaluation of the supportiveness of new interactions.

Adolescent↗
PubMed1991

Smoking and movement disorders in psychiatric patients.

Previous studies have suggested that tardive dyskinesia may occur more frequently in patients who smoke. Further evidence of an interaction between smoking and movement disorders includes the low lifetime exposure to cigarettes found in Parkinson's disease patients. In this study 126 patients with chronic psychiatric illnesses were blindly evaluated for tardive dyskinesia, neuroleptic-induced parkinsonism, and akathisia. Patients who smoked received significantly higher doses of neuroleptics but did not have significantly more frequent or more severe tardive dyskinesia or parkinsonism. Female smokers did have significantly more akathisia. These results are discussed with regard to interactions between smoking, central dopaminergic tone, and the psychopathology of extrapyramidal syndromes. The effect of smoking on neuroleptic blood levels as well as clinical symptomatology is also discussed.

Adult↗
PubMed1984

Lack of association between intraocular melanoma and cutaneous dysplastic nevi.

The occurrence of uveal and cutaneous malignant melanoma and the dysplastic nevus syndrome in the same individual suggests an etiologic relationship among these diseases. Thus, the dysplastic nevus syndrome could be viewed as marking an increased risk of both cutaneous and ocular melanoma. We postulated that if such a relationship exists, patients with both forms of melanoma should have a high prevalence of dysplastic nevi. We examined 44 patients (31 women and 13 men ranging in age from 20 to 80 years) with uveal melanoma for evidence of cutaneous melanoma and dysplastic nevi. We also examined photographs of 46 patients (24 men and 22 women ranging in age from 19 to 67 years) with nonfamilial cutaneous melanoma to determine the prevalence of dysplastic nevi. We found a 4.5% prevalence of dysplastic nevi in patients with uveal melanoma, significantly lower than the 41% prevalence in patients with cutaneous melanoma (two of 44 patients vs 19 of 46 patients). This study indicates that uveal and cutaneous melanoma are not etiologically linked through dysplastic nevi and suggests that patients with uveal melanoma are no more likely to have cutaneous dysplastic nevi than the general population.

Adult↗
PubMed1984

A study of tumor progression: the precursor lesions of superficial spreading and nodular melanoma.

Six evident lesional steps of tumor progression form the neoplastic system that affects the human epidermal melanocyte: 1) the common acquired melanocytic nevus; 2) a melanocytic nevus with lentiginous melanocytic hyperplasia, i.e., aberrant differentiation; 3) a melanocytic nevus with aberrant differentiation and melanocytic nuclear atypia, i.e., melanocytic dysplasia; 4) the radial growth phase of primary melanoma; 5) the vertical growth phase of primary melanoma; and 6) metastatic melanoma. The common acquired melanocytic nevus is viewed as a focal proliferation of melanocytes, destined in most instances to follow a programmed pathway of differentiation that leads to disappearance of the nevus. If the pathway of differentiation is not followed, characteristic lesions result, and such lesions are regarded as the formal histogenetic precursors of melanoma. Such a developmental flaw is termed aberrant differentiation, and the resultant precursor lesion is designated melanocytic dysplasia. The vast majority of melanocytic nevi showing melanocytic dysplasia are terminal lesions that do not progress to melanoma. If melanoma is to develop via a precursor lesion, however, the nevus with melanocytic dysplasia is that precursor. When melanomas do develop, they develop focally within the precursor. The resultant primary melanoma itself does not follow a pathway of inexorable expansion of a population of melanoma cells in space and time. Rather, primary melanomas, with the exception of nodular melanoma, also evolve in a stepwise fashion. The first step, termed the radial growth phase, is characterized by the net enlargement of the tumor at its periphery, along the radii of an imperfect circle. Tumors in this stage of development show a characteristic pattern of growth within the epidermis and a distinctive form of invasion of the papillary dermis. Such melanomas are not associated with metastasis, and it is hypothesized that such tumors do not have competence for metastasis. For a melanoma to acquire competence for metastasis it must progress to the next step of tumor progression--the vertical growth phase. This lesional step is characterized by the appearance of a new population of cells within the melanoma, not an expansion of the cells forming the pre-existing radial growth phase. The net growth of the cells of the vertical growth phase is perpendicular to the directional growth of the radial growth phase. As a rule, the cells of the vertical growth phase grow in an expansile fashion, expansile as a balloon expands: a growth form characteristic of metastases.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

Invasive malignant melanomas lacking competence for metastasis.

Two stages of progression have been described in malignant melanomas, namely, the so-called "radial" and "vertical" phases of growth. We sought the presence or absence of vertical growth in 211 invasive cutaneous malignant melanomas. Disease-free survival in 146 patients with vertical growth was 63.7%, whereas 100% of 65 patients whose neoplasms lacked this feature survived 5 years or more after ablation of their lesions without evidence of recurrence or metastasis. Microstaging of patients with malignant melanoma by traditional means (level of invasion and thickness) identifies groups of patients at low and high risk of metastasis. Our data suggest that the absence of vertical progression of growth identifies a group of patients whose risk of metastasis is close to zero.

Humans↗
PubMed1983

Optimal resection margin for cutaneous malignant melanoma.

Cutaneous malignant melanoma has traditionally been treated by "wide" local excision with a 5-cm margin of normal skin about the tumor. The rationale of wide excision for melanoma has never been clearly defined, but the procedure is known to be effective in preventing local recurrence. We studied 105 patients who had 109 primary melanomas in 1977 and related margin width of the definitive excision to the presence of satellites, to the subsequent development of local recurrence and in-transit metastases, and to survival. Survival was not dependent on margin width, and there were no incidences of local recurrence. Satellitosis and in-transit cutaneous metastasis indicate that a melanoma is capable of local recurrence; these phenomena occurred only in tumors whose thickness (Breslow) was greater than 2.0 mm. These data provide a rationale for wide excision of "thick" melanomas and support more modest local therapy for thin cutaneous melanoma.

Adult↗
PubMedDate not supplied

Using process evaluation to describe a hospital-based clinic for children coping with medical stressors.

OBJECTIVE: To use process evaluation methods to describe the development of a hospital-based mental health clinic for children facing medical stressors. METHODS: Over a 21-month time period, we collected data regarding presenting concern, service use, and referral source using hospital administrative, clinic intake, and clinical records for 356 children. RESULTS: Nearly 90% of the children were referred to the clinic from sources within the hospital. With the exception of single session interventions, there were no differences in average length of services according to presenting concern. Hospital pediatric specialists and psychology consultants were the primary referrers to the program. Pediatric specialists referred more often for procedural concerns and chronic illness than other hospital referrers. CONCLUSIONS: These findings support the feasibility and usefulness of a process evaluation approach in shaping clinical program directions, creating opportunities for collaboration with medical providers, and planning effectiveness research.

Adaptation, Psychological↗