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Biomedical subjects

M Ireland

Publications and source records attributed to M Ireland.

At least 55 records · Page 3Linked to original sources
PubMed1997

Protecting adolescents from harm. Findings from the National Longitudinal Study on Adolescent Health.

CONTEXT: The main threats to adolescents' health are the risk behaviors they choose. How their social context shapes their behaviors is poorly understood. OBJECTIVE: To identify risk and protective factors at the family, school, and individual levels as they relate to 4 domains of adolescent health and morbidity: emotional health, violence, substance use, and sexuality. DESIGN: Cross-sectional analysis of interview data from the National Longitudinal Study of Adolescent Health. PARTICIPANTS: A total of 12118 adolescents in grades 7 through 12 drawn from an initial national school survey of 90118 adolescents from 80 high schools plus their feeder middle schools. SETTING: The interview was completed in the subject's home. MAIN OUTCOME MEASURES: Eight areas were assessed: emotional distress; suicidal thoughts and behaviors; violence; use of 3 substances (cigarettes, alcohol, marijuana); and 2 types of sexual behaviors (age of sexual debut and pregnancy history). Independent variables included measures of family context, school context, and individual characteristics. RESULTS: Parent-family connectedness and perceived school connectedness were protective against every health risk behavior measure except history of pregnancy. Conversely, ease of access to guns at home was associated with suicidality (grades 9-12: P<.001) and violence (grades 7-8: P<.001; grades 9-12: P<.001). Access to substances in the home was associated with use of cigarettes (P<.001), alcohol (P<.001), and marijuana (P<.001) among all students. Working 20 or more hours a week was associated with emotional distress of high school students (P<.01), cigarette use (P<.001), alcohol use (P<.001), and marijuana use (P<.001). Appearing "older than most" in class was associated with emotional distress and suicidal thoughts and behaviors among high school students (P<.001); it was also associated with substance use and an earlier age of sexual debut among both junior and senior high students. Repeating a grade in school was associated with emotional distress among students in junior high (P<.001) and high school (P<.01) and with tobacco use among junior high students (P<.001). On the other hand, parental expectations regarding school achievement were associated with lower levels of health risk behaviors; parental disapproval of early sexual debut was associated with a later age of onset of intercourse (P<.001). CONCLUSIONS: Family and school contexts as well as individual characteristics are associated with health and risky behaviors in adolescents. The results should assist health and social service providers, educators, and others in taking the first steps to diminish risk factors and enhance protective factors for our young people.

Adolescent↗
PubMed1997

Management of childhood gastroenteritis in the community.

OBJECTIVE: To examine general practitioners' (GPs') management of childhood gastroenteritis and their perceptions about barriers to optimal management in the community. DESIGN: Cross-sectional postal survey in which GPs' self-reported practices were assessed by a paediatric gastroenterologist for compliance with published guidelines. SETTING: Hunter region of NSW, mid 1994. PARTICIPANTS: All 422 urban and rural GPs practising in the Hunter region were sent questionnaires; 289 (243 urban and 46 rural) GPs responded. RESULTS: Nearly all GPs (97%) recommended clear fluids in the management of childhood gastroenteritis, with 195 (67%) recommending oral electrolyte solution. Management practices were assessed as: optimal, 170 GPs (59%); acceptable, 33 GPs (11%); inappropriate or potentially dangerous, 38 GPs (13%); and too vague to classify, 48 GPs (17%). Multiple logistic regression analysis showed that better management strategies were associated with being younger and practising in rural areas. GPs perceived the main barriers to effective management of gastroenteritis were: inadequate parenting skills, 131 GPs (45%); lack of parental understanding about the illness, 118 GPs (41%); other social problems, 67 GPs (23%); parental anxiety, 57 GPs (20%); and conflicting advice given by others, 42 GPs (15%). Only 33 GPs (11%) identified the taste and 16 (6%) the cost of oral electrolyte solution as major barriers. CONCLUSIONS: Most GPs reported management of gastroenteritis was acceptable, although not necessarily optimal. GPs need to ensure that parents fully understand the nature of their child's illness and their recommendations for management at home.

Child↗
PubMed1997

Large scale deletions in the GPC3 gene may account for a minority of cases of Simpson-Golabi-Behmel syndrome.

AIMS OF THE STUDY: To identify the proportion and type of deletions present in the glypican 3 (GPC3) gene in a group of patients with Simpson-Golabi-Behmel syndrome (SGBS). SUBJECTS AND METHODS: PCR analysis using primer pairs which amplify fragments from each of the eight exons of the GPC3 gene was carried out in a series of 18 families with SGBS (approximately half of reported cases). RESULTS: Deletions were detected in only five families (one reported previously). We found deletions in all exons of the gene except exon 3. CONCLUSIONS: Our results suggest that large scale deletions may be less common in SGBS than was originally thought. One patient, with an exon 4 and 5 deletion, lacked the characteristic facial dysmorphic features. This raises the possibility of involvement of GPC3 gene defects in a wider range of overgrowth disorders.

Abnormalities, Multiple↗
PubMed1997

De Lange syndrome: subjective and objective comparison of the classical and mild phenotypes.

Classical de Lange syndrome presents with a striking face, pronounced growth and mental retardation, and variable limb deficiencies. Over the past five years, a mild variant has been defined, with less significant psychomotor retardation, less marked pre- and postnatal growth deficiency, and an uncommon association with major malformations, although mild limb anomalies may be present. We have evaluated 43 subjects with de Lange syndrome, 30 with classical features, aged from birth to 21 years, and 13 with the mild phenotype, aged from 18 months to 30 years. In addition to assessment of gestalt and facial change with time, detailed craniofacial measurements have been obtained on each subject and composite pattern profiles compiled. The characteristic face of classical de Lange syndrome is present at birth and changes little throughout life, although there is some lengthening of the face with age and the jaw becomes squared. In mild de Lange syndrome, the characteristic classical appearance may be present at birth, but in some subjects it may be two or three years before the typical face is obvious. In general, the overall impression is less striking, perhaps because of increased facial expression and greater alertness. With age, the face loses the characteristic appearance, the nasal height increases, the philtrum does not seem as long, and the upper vermilion is full and everted, although the crescent shaped mouth with downturned corners remains. Eyebrows may be full and bushy. Objective comparison of the face in mild and classical de Lange syndrome, through the use of craniofacial pattern profiles, shows marked similarity of patterns at 4 to 9 years; both groups have microbrachycephaly, but the individual dimensions of the mild group are slightly closer to normal than their classical counterparts. The correlation coefficient is high (0.83). In the adult groups, similarity of patterns remains but is less marked. The normalisation of scores in the mild group is more dramatic. The correlation coefficient is lower (0.71). These objective findings substantiate clinical impressions of a phenotypic dichotomy. Early in life, the craniofacial features in mild de Lange syndrome may be indistinguishable from the classical phenotype and alternative discriminators must be sought in order to identify those subjects in whom the prognosis is more optimistic. Birth weight of more than 2500 g and absence of major limb anomalies may help in this regard.

Adolescent↗
PubMed1997

Adolescent sexual aggression: risk and protective factors.

OBJECTIVE: Little research addresses the correlates of sexual aggression in nonclinical populations of adolescents. The purpose of this study was to identify risk and protective factors associated with sexual violence among male and female adolescents. METHODS: We analyzed data on 71,594 students in the 9th and 12th grades responding to the 1992 Minnesota Student Survey, an anonymous, self-report survey examining an array of risk environments, health-compromising behaviors, and protective factors. The responses of students reporting a history of forcing someone into a sexual act were compared with those who reported that they had never forced someone into a sexual act. Separate analyses were conducted for males and females. RESULTS: A history of sexual violence perpetration was reported by 4.8% of male and 1.3% of female adolescents. Using a logistic regression model, sexual aggression was associated with experiencing intrafamilial or extrafamilial sexual abuse, witnessing family violence, frequent use of illegal drugs, anabolic steroid use, daily alcohol use, gang membership, high levels of suicide risk behavior, and excessive time spent "hanging out." Emotional health and connectedness with friends and adults in the community were protective factors for male adolescents against sexually aggressive behavior, and academic achievement was a protective factor for female adolescents. CONCLUSIONS: A history of forcing someone into a sexual act was associated with several risk and protective factors. Efforts to prevent adolescent sexual violence should target individuals at increased risk. Through their psychosocial assessment of young people, health care professionals can play a role in identifying, counseling, and making appropriate referrals for adolescents at risk for sexually aggressive behavior.

Adolescent↗
PubMed1996

Thermal response in murine L929 cells lacking alpha B-crystallin expression and alpha B-crystallin expressing L929 transfectants.

We investigated the role of alpha B-crystallin expression in the development of thermotolerance in murine L929 cells. An initial heat-shock of 10 min at 45 degrees C induced thermotolerance in these cells to a heat challenge at 45 degrees C administered 24 h later. The thermotolerance ratio at 10(-1) isosurvival was 1.7. Expression of alpha B-crystallin gene was not detected during the 24 h incubation at 37 degrees C following heat shock by either northern or western blots. In contrast, inducible HSP70 synthesis was observed during this time period. Thus, this cell line provided an unique system in which to examine the effects of transfected alpha B-crystallin on thermoresistance and thermotolerance. Cells stably transfected with alpha B-crystallin under the control of an inducible promoter did not show a significant increase in the ability to develop thermotolerance. However, a stably transfected L929 clone expressing high levels of constitutive alpha B-crystallin exhibited an approximately 50% increase in thermal resistance over parental and control cells. Though expression of alpha B-crystallin is not requisite for the development of thermotolerance in L929 cells, overexpression of transfected alpha B-crystallin can contribute to increased thermoresistance.

3T3 Cells↗
PubMed1996

Growth of Hmong children.

OBJECTIVE: To investigate the growth of a group of young Hmong children. DESIGN: In this descriptive, comparative study, length and weight measures of Hmong children were abstracted from medical charts for each previous clinic visit (newborn to most recent visit) where both measures had been recorded, and measures were compared with National Center for Health Statistics (NCHS) standard percentiles. Visits occurred from 1988 to 1994. PARTICIPANTS AND SETTING: Participants were 579 Hmong children, ages 0 to 5 years, who were active patients at a family practice residency clinic. MAIN OUTCOME MEASURES: Length and weight. RESULTS: This group of Hmong children showed lengths similar to those of the NCHS reference population for the first 6 to 12 months of life, after which they lagged behind reference lengths. By the 24th month, median length for Hmong girls and boys was less than the NCHS 25th percentile. The Hmong children's average weight was slightly higher than the NCHS median until about 8 months of age, after which the distributions were similar. CONCLUSIONS: Compared with children who comprise the NCHS reference population, the Hmong children in this study were slightly heavier in the first several months of life, and shorter thereafter. Therefore, in general, the Hmong children were proportionately heavier than other children of similar height.

Anthropometry↗
PubMed1995

Cataract surgery outcomes: importance of co-morbidities in case mix.

Variation in patients' preoperative co-morbidities can have a significant effect on the outcomes of cataract surgery. To examine the effects of that variation, we did a retrospective study of the outcomes of extracapsular cataract surgery performed by seven surgeons. Medical records from 791 surgeries done from June 1, 1986, through May 31, 1989, were retrospectively examined. Variations in postoperative visual acuity and intraoperative and postoperative complications were documented. The relationships between preoperative ocular and systemic medical co-morbidities and postoperative visual results and complications were studied. A statistical model was developed to adjust for the preoperative co-morbidity case mix between physicians. Visual acuity rates varied by surgeon and surgical volume, but not significantly when adjusted for patient case mix.

Adult↗
PubMed1995

In the immature mouse, Pseudomonas aeruginosa pili bind a 57-kd (alpha 2-6) sialylated corneal epithelial cell surface protein: a first step in infection.

PURPOSE: To test the hypothesis that in the unscarified immature eye, Pseudomonas aeruginosa pili bind glycoprotein receptors, one or more of which are surface associated. METHODS: Several methods--including radioiodination of bacterial pili and surface-associated corneal epithelial proteins (CEPs), solid-phase binding assays, carbohydrate detection, and immunoblotting techniques in which periodate oxidation and preincubation of blots with purified pili, neuraminidase, sialic acid, other sugars, and SNA and MAA lectins--were used to identify and characterize host proteins. Some of these proteins in the immature mouse corneal epithelium interacted with bacterial pili. RESULTS: Seven proteins, with molecular weights from 14 to 66 kd were identified that strongly bound PAK/PR1 pili. To determine if any protein(s) was cell surface localized, corneal epithelial surface membrane proteins were radioiodinated and examined using a pilus overlay assay and lectin analysis. Only one protein of 57 kd was cell surface labeled and bound pili in an overlay assay. This protein was alpha (2-6) sialylated, as shown by SNA binding. Furthermore, SNA lectin was able to block pilus binding to CEPs. 125I labeling of pili and a solid-phase binding assay confirmed that pili bind to CEPs and, further, that binding could be competitively inhibited by excess unlabeled pili and that the receptors appeared saturable. GlycoTrack reagents were used to show that the epithelial proteins of the postnatal day 5 (P5) mouse cornea were glycosylated. Removal of carbohydrates by preincubation of blots with periodate, or combining pili with sialic acid, eliminated pili binding. Pretreatment of blots with either neuraminidase (N'ase) to decrease and/or remove sialic acid residues, or pretreatment with SNA lectin with specificity for alpha (2-6) linked sialic acid to galactose, also diminished pili binding to CEPs. Other sugars or MAA lectin, specific for sialic acid alpha (2-3) linked to galactose, had no inhibitory effect. CONCLUSIONS: These data show that a 57-kd surface membrane protein bound pili in the immature cornea and that for both this protein and the other nonsurface proteins, sialic acid alpha (2-6) linked to galactose was important in receptor recognition by the pilus adhesion. The 57-kd protein is putatively important in the initial interaction of pili with the unwounded ocular epithelium and may be the initial pathogenic event in this model.

Animals↗
PubMed1994

Mapping of Simpson-Golabi-Behmel syndrome to Xq25-q27.

Simpson-Golabi-Behmel syndrome (SGBS) is an X-linked gigantism syndrome characterized primarily by a coarse facies and somatic overgrowth which we have observed to be associated with an increased risk for embryonal tumors. Genetic linkage analysis for two SGBS kindreds in which X linked dominant inheritance was observed has been conducted for the X chromosome. The closest linkage to SGBS was observed for the Xq26 locus HPRT (Z max = 7.45, theta max = 0.00). SGBS-Xq marker recombinations map the disease locus to the DXS425-DXS1123 interval on Xq25-q27. This maps the disease locus to a region known to contain a previously characterized chromosomal translocation breakpoint found in a young girl with somatic overgrowth. This observation may have implications for the cloning of the SGBS gene.

Base Sequence↗
PubMed1993

Brachmann-de Lange syndrome. Delineation of the clinical phenotype.

A total of 31 cases previously diagnosed as having Brachmann-de Lange syndrome were ascertained and examined, of which 11 were thought to have been misdiagnosed. Of those correctly diagnosed, there appeared to be a phenotypic dichotomy with classical and mild cases. Those facial findings of greatest diagnostic value were the combination of the characteristic eyebrows, long philtrum, thin lips and crescent-shaped mouth. The characteristic eyebrows were neat, well defined and arched as though they had been pencilled. This combination of anomalies was absent in postpubertal males but not in postpubertal females. Facial abnormalities most likely to lead to incorrect use of the eponym were hypertrichosis, synophrys, and bushy eyebrows.

Adolescent↗
PubMed1993

Radiological features in Brachmann-de Lange syndrome.

Brachmann-de Lange syndrome (BDLS) is a well-delineated disorder consisting variably of pre- and postnatal growth deficiency, microbrachycephaly, characteristic face, hypertrichosis, visceral anomalies, and limb defects consisting primarily of variable limb reduction defects, micromelia, and elbow abnormalities. The course is usually marked by initial hypertonicity, low-pitched weak cry, feeding problems, and behavioral problems with marked mental deficiency. In classical cases there is rarely any difficulty in making the diagnosis, but for mildly affected cases, it may be difficult to feel secure about the diagnosis. In an effort to increase the precision of diagnosis for mildly affected cases, we reviewed roentgenograms in 21 cases of Brachmann-de Lange syndrome, as well as previously published descriptions of the radiological manifestations. Unusual radiologic manifestations were related primarily to the limb anomalies, and these were often asymmetric. These manifestations included digital abnormalities, which ranged from acheiria to oligodactyly, hypoplasia of the thumb and first metacarpal, clinodactyly of the fifth finger, or ectrodactyly. Long bone abnormalities included ulnar a/hypoplasia, dysplasia of the radial head, or fusion of the elbow. When there was a single forearm bone, there was often fusion at the elbow and oligodactyly, which made it difficult to determine whether the radius or ulna was absent. Other radiologic manifestations included 13 ribs with precocious sternal fusion, and micrognathia. We suggest that these radiologic manifestations could increase diagnostic precision in mildly affected cases.

Child↗
PubMed1993

Cornelia de Lange syndrome--photo essay.

Cornelia de Lange syndrome is a rare developmental malformation syndrome characterized by developmental delay, retardation of growth, limb reduction abnormalities and dysmorphic facial features. With the exception of one case with a de novo translocation (Ireland et al., 1991) there are no consistent chromosomal abnormalities or biochemical markers. Diagnosis is therefore dependent on the recognition of the distinctive facial features. In this photo essay we focus on those features which are most specific to the syndrome and highlight possible diagnostic pitfalls.

Adolescent↗
PubMed1992

Platyspondylic lethal osteochondrodysplasia: Shiraz type with radiological-pathological correlation.

We report two cases of a platyspondylic lethal osteochondrodysplasia in siblings. The condition affects predominantly the metaphyses of the axial skeleton associated with limb shortening and mild platyspondyly. The radiological and pathological features correlate very closely with Sedaghatian's lethal metaphyseal chondrodysplasia, which has previously been described only in Iranian Nationals. Both the radiological and pathological appearances will be described, together with a discussion of the differential diagnosis, the genetical implications and a review of literature.

Female↗
PubMed1992

Functional characterization of insulin and IGF-I receptors in chicken lens epithelial and fiber cells.

Insulin and insulin-like growth factor I (IGF-I) play a role in lens cell growth and development. The binding of these hormones to their respective receptors with its concomitant signal transduction is an important step in these cellular processes. Hormone binding to adult chicken lens insulin and IGF-I receptors, partially purified from epithelial and fiber cells, was studied to examine this activity in lens. The associated stimulation of receptor-mediated tyrosine kinase by the hormones was also studied. At an insulin concentration of 0.02 nM, specific binding was similar for epithelial and fiber receptor preparations (Epi = 0.23 +/- 0.03 fmol, Fib = 0.19 +/- 0.02 fmol). Displacement studies revealed that there was also no difference between epithelial and fiber receptor preparations in the concentration of insulin necessary for half maximal displacement of specific [125I]-insulin binding (IC50: Epi = 0.32 nM +/- 0.07 nM, Fib = 0.31 nM +/- 0.05 nM). Comparison of IGF-I (0.02 nM) binding to receptor preparations from epithelial and fiber cells demonstrated that specific binding was similar in the two preparations (Epi = 0.50 +/- 0.05 fmol, Fib = 0.42 +/- 0.05 fmol). Also, there was no difference in the concentration of IGF-I necessary for half maximal displacement of specific [125I]-IGF-I binding (IC50 = Epi: 0.27 +/- 0.05 nM, Fib: 0.28 +/- 0.04 nM). The ability of IGF-I to displace bound [125I]-insulin was also examined. The IC50 for IGF-I binding to the insulin receptors isolated from epithelial and fiber cells was 37.4 +/- 2.4 nM, and 35.4 +/- 2.8 nM, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗