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Biomedical subjects

A Young

Publications and source records attributed to A Young.

At least 145 records · Page 8Linked to original sources
PubMed1997

Labour force participation and employment among a sample of Australian patients with a spinal cord injury.

This study examined the employment achievements of 219 spinal cord injured people and attempted to identify predictors which, individually and in combination, (a) discriminated between those who were in the labour force or not, and (b) correlated with the amount of time in employment post injury. Results indicated that at the time of the survey 26% were in full-time work, 11% were in part-time work, 4% were unemployed and 59% were not actively seeking work. Multivariate analyses identified three variables (impairment type, study since injury, level of pre-injury secondary schooling) which were related to both labour force participation and the amount of work undertaken post-injury. These results are discussed with reference to post-injury services that could be offered to spinal cord injury people who wish to return to work or gain employment.

Adolescent↗
PubMed1997

Nitric oxide synthase activity and localization do not change in uterus and placenta during human parturition.

Animal studies have suggested that nitric oxide, a smooth muscle relaxant, is a fundamental mediator in the initiation of parturition. The purpose of this study was to test the hypothesis that the onset of human labour is associated with a reduction in the activity of the enzyme nitric oxide synthase (NOS), within the uterus. Samples of myometrium, placenta, decidua and fetal membranes were collected during Caesarean section from 11 women before and 11 women after the onset of labour at term. Immunocytochemistry was used to localize each of the three isoforms of NOS (endothelial NOS, brain NOS, and inducible NOS) in each of these tissues and the intensity of staining was qualitatively assessed. NOS enzyme activity was determined in homogenates of frozen myometrium, placenta and fetal membranes (with attached decidua), by measuring conversion of radio-labelled L-arginine to L-citrulline. Each of the three isoforms of NOS was localized in each of the tissues. We found no difference in either the expression or enzyme activity of NOS in myometrium, placenta or fetal membranes before and during labour at term. These results suggest that, in contrast to animal studies, a decrease in NOS enzyme activity may not be involved in the onset of parturition at term in the human.

Enzyme Activation↗
PubMed1997

Conceptualizing parents' sign language use in bilingual early intervention.

This research study investigates how parents and interveners conceptualize parents' early sign language use. Three groups of respondents involved in the same bilingual early intervention program were being interviewed: hearing parents (n = 12), hearing teachers (n = 6), and Deaf consultants (n = 6). The search and retrieve program 'The Ethnograph' was used for data analysis. The results demonstrate that neither a framework of linguistic proficiency nor one of communicative competence captures the complexity of the issues involved for parents and interveners in conceptualizing parents' early sign language use. The interpretative frameworks of each group emphasize different aspects of the task facing parents: balancing the quest for Sign Language proficiency with emotional and practical considerations in the family, acknowledging the overriding importance of communication regardless of what one may label the language used, and confirming the visual quality and child appropriateness of the signing. Results are related to the stocks of knowledge on which respondents draw and the implications for Deaf and hearing interveners assessing parents' progress.

Journal Article↗
PubMed1997

Use of the short form 36 (SF36) for health status measurement in rheumatoid arthritis.

The patient-administered Health Assessment Questionnaire (HAQ) is widely used in rheumatology studies. Another health quality assessment technique commonly used for other non-rheumatological conditions is the 'Short Form 36' (SF36). This has questions designed to assess eight aspects of health ranging from physical limitations to general perceptions of vitality and mental well-being. This study presents information on the health status of 137 patients with rheumatoid arthritis (RA) assessed by both the SF36 and HAQ. Summary statistics are given for the elements of the SF36 according to age, gender, disease measures of RA and the presence of co-morbidity. There were significant associations between the physical functioning score of the SF36 and the HAQ score. with other measures of disease activity and severity, and with co-morbidity, although there was considerable inter-patient variability. These findings suggest that future applications of health status questionnaires are possible.

Adult↗
PubMed1997

Bilateral clinical anophthalmos.

We report on the risk factors, associations and outcome of 5 children with bilateral clinical anophthalmos. Our study showed no gestational, environmental or hereditary association but confirmed strong association with multiple systemic abnormalities.

Abnormalities, Multiple↗
PubMed1997

On the rôle of human salivary micelle-like globules in bacterial agglutination.

The hypothesis to be tested in this in vitro study was that the salivary micelle-like globules (SMGs) have a rôle in the agglutination of some oral bacteria. An attempt to determine the mechanisms for the interactions involved was also carried out. 4 laboratory and 4 native streptococci strains were tested. Human whole (HWS) and parotid (HPS) saliva was collected from 4 subjects, and SMGs were isolated from both salivas, and agglutination was recorded in the various bacterial suspensions over time. HPS, HWS and SMGs isolated from HPS and HWS caused typical agglutination patterns for the mutans strains. Salivary supernatants (without SMGs) caused a much delayed or no agglutination. Electron microscopy showed SMG-like structures on the surface of the agglutinated bacteria. Addition of pyrophosphate to HPS prevented agglutination, whereas guanidine HCl prevented normal agglutination of a sanguis strain, and urea had no obvious effect. Together, these results indicate that the SMGs are important in the agglutination of streptococci, and that both calcium-dependent, electrostatic and hydrophobic interactions may be involved.

Adult↗
PubMed1997

Fractionation of salivary micelle-like structures by gel chromatography.

Globular structures have been demonstrated in human parotid saliva by transmission electron microscopy and photon correlation spectroscopy. The aim of this study was to fractionate these salivary globular structures for analytical and preparative purposes using a gel-filtration material capable of separating spherical particles up to 300-400 nm in diameter. Freshly obtained parotid saliva was applied to a Sephacryl S-1000 column. Peak fractions were collected and prepared for transmission electron microscopy (TEM) or for amino acid analysis. Bovine milk was included as the casein micelles by TEM appear to be similar to the salivary aggregates and their elution profiles are known. The salivary globular structures were eluted in one major peak. TEM of negatively stained samples from the peak fractions demonstrated globular protein aggregates consistent with the salivary structures in parotid saliva. Amino acid analysis showed characteristic amino acid profiles with unusual high levels of proline, 40-45%. The casein micelles were eluted in one major peak and separated from the whey proteins. This study indicates that the salivary globular structures can be isolated by gel chromatography. The amino acid analysis indicates that proline-rich proteins may be an important fraction of the salivary globular structures.

Adult↗
PubMed1997

Ankylosing spondylitis in West Africans--evidence for a non-HLA-B27 protective effect.

OBJECTIVE: To determine the prevalence of ankylosing spondylitis in the Fula ethnic group in The Gambia, and relate the disease prevalence to the B27 frequency and subtype distribution of that population. METHODS: 215 first degree relatives of 48 B27 positive Fula twin pairs, and 900 adult Fula males were screened for ankylosing spondylitis by clinical and, where appropriate, radiographic means. The B27 prevalence was determined by PCR/sequence specific oligonucleotides on finger prick samples from 100 unrelated Fula, and B27 subtype distribution by SSCP on unrelated B27 positive individuals. This data were then compared with the prevalence of ankylosing spondylitis among B27 positive Caucasians. RESULTS: No case of ankylosing spondylitis was seen. Six per cent of Fula are B27 positive, of which 32% are B*2703 and 68% B*2705. Assuming the penetrance of ankylosing spondylitis in B27 positive Fula is the same as in B27 positive Caucasians, the probability of not observing any cases of ankylosing spondylitis among the Fula examined is remote (P = 6.7 x 10(-6)). Similarly, the chance of not seeing any cases among those expected to be either B*2705 or B*2703 was small (P = 3.2 x 10(-4) for B*2705, and P = 0.02 for B*2703). CONCLUSIONS: The risk of developing ankylosing spondylitis in B27 positive Fula is lower than in B27 positive Caucasians. This is not explained by the B27 subtype distribution among Fula, and suggests the presence of some non-B27 protective factor reducing the prevalence of ankylosing spondylitis in this population.

Adult↗
PubMed1997

The cutaneous-vulvar clinic revisited: a 5-year experience of the Columbia Presbyterian Medical Center Cutaneous-Vulvar Service.

OBJECTIVE: To review the recent experience of a busy referral cutaneous-vulvar service. STUDY DESIGN: 500 randomly chosen charts from the last 5 years of patients seen at the Columbia Presbyterian Medical Center Cutaneous-Vulvar Service were reviewed. Information was entered into a computer data base and analyzed. RESULTS: The most common presenting condition was vulvar vestibulitis (36.2%), followed by lichen sclerosus (19.2%) and vaginitis/vaginosis (14.8%). Most patients had undergone a variety of therapies prior to referral. Many were treated for moniliasis in the absence of clinical evidence prior to our evaluation. Most patients responded well to appropriate therapy. CONCLUSIONS: A variety of primary care providers see women with cutaneous-vulvar symptomatology. Awareness of prevalent conditions will lead to correct diagnosis and treatment. We emphasize the importance of interdisciplinary consultation in difficult cases.

Adult↗
PubMed1997

Zeta potentials of human enamel and hydroxyapatite as measured by the Coulter DELSA 440.

The zeta potential of human enamel is of physiological importance for interactions between enamel surfaces and the surrounding aqueous medium of saliva. The zeta potentials of both enamel and hydroxyapatite (HA) have been examined previously by various techniques. In this study, we examined the zeta potential of human enamel and HA using the Coulter DELSA 440, which, by a laser, makes independent Doppler shift measurements of moving particles in an electric field at 4 different angles, providing advantages over previous techniques. The enamel and HA particles were suspended directly in different phosphate buffers, or first incubated for 2 hrs in parotid (PS) or whole saliva (HWS) and then suspended in the same buffers. The enamel and HA particles exhibited an overall net surface potential of -15 to -30 mV, depending on the buffer content. Incubation in PS and HWS gave less negative potentials of -8 to -14 mV. In our previous studies, the salivary micelle-like structures (SMSs), seen in TEM of parotid saliva, were observed to have a zeta potential of -9 mV (Rykke et al., 1996). The zeta potential determinations in this study support the concept of an adsorption of mostly SMSs to the enamel surfaces, with a change of the zeta potential of the enamel and HA toward that of the SMSs.

Adsorption↗
PubMed1996

The lifetimes and energies of the first excited singlet states of diadinoxanthin and diatoxanthin: the role of these molecules in excess energy dissipation in algae.

The lifetimes of the first excited singlet states (2(1)A(g)) of diadinoxanthin and diatoxanthin, carotenoids involved in the xanthophyll cycle in some genera of algae, have been measured by femtosecond time-resolved optical spectroscopy to be 22.8 +/- 0.1 ps and 13.3 +/- 0.1 ps, respectively. Using the energy gap law for radiationless transitions set forth by Englman and Jortner (Mol. Phys. 18 (1970) 145-164), these lifetimes correspond to S1 excited state energies of 15210 cm-1 for diadinoxanthin and 14620 cm-1 for diatoxanthin. The lowest excited singlet state energy of Chl a has an energy of 14700 cm-1. The fact that the S1 state energy of diadinoxanthin lies above that of Chl a, whereas the S1 state energy of diatoxanthin lies below that of Chl a, suggests that the xanthophyll cycle involving the enzymatic interconversion of diadinoxanthin and diatoxanthin may play a role in regulating energy flow between these molecules and Chl a in many species of algae, essentially fulfilling a role identical to that proposed for violaxanthin and zeaxanthin in higher plants and green algae (Frank et al. (1994) Photosyn. Res. 41, 389-395).

Carotenoids↗
PubMed1996

A genome-wide search for quantitative trait loci underlying asthma.

Asthma now affects one child in seven in the United Kingdom. Most cases (95%) of childhood asthma are associated with atopy, the immunoglobulin E (IgE)-mediated familial syndrome of allergic asthma, eczema and rhinitis. Segregation analysis has consistently suggested the presence of major genes influencing atopy and IgE levels, with the expectation that these genes may be identified by positional cloning or the examination of candidate genes. Here we report the results of a genome-wide search for linkage to one qualitative and four quantitative traits associated with allergic (atopic) asthma. We have identified six potential linkages (P<0.001), five of which are to quantitative traits. Monte Carlo simulations show that 1.6 false-positive linkages at this level of significance would be expected from the data. One linkage, to chromosome 11q13, has been established previously. Three of the new loci show evidence of linkage to a second panel of families, in which maternal effects and pleiotropy of linked phenotypes are seen. The results demonstrate the extent and the complexity of the genetic predisposition to asthma.

Adolescent↗
PubMed1996

Two loci of repetition priming in the recognition of familiar faces.

Four experiments examining the repetition priming of familiar face recognition are reported. The experiments showed that the speed of deciding whether a face is familiar was facilitated by prior presentation of the face, but not by reading the written name or by producing the name in response to a definition. In contrast, reading names and producing names to definitions both primed subsequent naming of the corresponding faces (Experiments 1 and 2). Face naming was primed more by face naming than by either familiarity decisions or naming from description (Experiments 3 and 4). The authors propose that repetition priming of familiar face recognition occurs at 2 distinct loci. The first involves the perceptual recognition of a face as familiar and is domain-specific. The second involves name retrieval and is susceptible to both within- and cross-domain priming.

Adult↗
PubMed1996

Negotiating the middle years: ego-resiliency and successful midlife adjustment in women.

Midlife is a time of heightened reevaluation and reorientation during which individuals are faced with potentially stressful changes and turning points. Ego-resiliency (ER) is proposed to be a powerful personality resource that enables individuals to adaptively negotiate the challenges of this period. Through examination of data from 2 longitudinal samples of women (N = 208), Study 1 examined whether observer-based and self-reported ER assessed at the beginning of midlife (at age 43) can predict life adjustments of specific relevance to this period assessed in late middle age (ages 52 and 48). In Study 2 age 43 ER was used to predict directional changes in central life adjustments and feelings about life over this same period (between ages 43 and 52). Predictions across samples, across measures of ER, or both were confirmed by replicated findings.

Adult↗
PubMed1996

Agalactosyl IgG [Gal(o)]--an analysis of its clinical utility in the long-term follow-up of patients with rheumatoid arthritis.

This long-term prospective study of patients with newly diagnosed RA assesses the relative value of certain clinical and laboratory measures at first consultation in order to determine factors that help to discriminate between patients likely to go into early remission and those with relapsing/remitting or persistent disease. Validation was sought in a similar group from a separate but comparable prospective study. Measures of clinical activity such as joint score, early morning stiffness (EMS) and acute phase (ESR) improved over 4 yr in both groups, whereas agalactosyl IgG [Gal(o)] levels increased. Using discriminant functional analysis in the first cohort to identify features at entry which would predict outcome at 4 yr, a combination of Gal(o), grip strength, age at onset and gender predicted the course of RA correctly in 95% of the patients. This combination was confirmed in the second cohort, although with reduced power (78% correct). Thus, we show that Gal(o) does not reflect activity of the disease like the ESR, but has greater potential as a prognostic index early in the course of disease.

Arthritis, Rheumatoid↗
PubMed1996

Drainage of CSF through lymphatic pathways and arachnoid villi in sheep: measurement of 125I-albumin clearance.

We investigated lymphatic drainage pathways of the central nervous system in conscious sheep and quantified the clearance of a cerebrospinal fluid (CSF) tracer into lymph and blood. In the first group of studies, 125I-HSA was injected into the lateral ventricles of the brain or into lumbar CSF and after 6 h, various lymph nodes and tissues were excised and counted for radioactivity. Multiple lymphatic drainage pathways of cranial CSF existed in the head and neck region defined by elevated 125I-HSA in the retropharyngeal/cervical, thymic, pre-auricular and submandibular nodes. Implicated in spinal CSF drainage were mainly the lumbar and intercostal nodes. In a second group of experiments, multiple cervical vessels and the thoracic duct were cannulated and lymph diverted from the animals. Transport of tracer through arachnoid villi was taken from recoveries in venous blood. Following intraventricular administration, the 6 h recoveries of 125I-HSA in the lymph (sum of cervical and thoracic duct) and blood were 8.2% +/- 3.0 and 12.5% +/- 4.5 respectively and at 22 h, 25.1% +/- 6.9 and 20.8% +/- 4.1 respectively. When 125I-HSA was injected into lumbar CSF, the 6 h recoveries of tracer in thoracic duct and blood were 11.6% +/- 2.7 and 16.3% +/- 3.7 respectively. Total lymph and blood recoveries were not significantly different in any experiment. We conclude that the clearance of 125I-HSA from the CSF is almost equally distributed between lymphatic and arachnoid villi pathways.

Animals↗
PubMed1996

Fluoride release and uptake in vitro from a composite resin and two orthodontic adhesives.

The aim of this study was to investigate the fluoride release and uptake characteristics of a composite resin (Tetric) and two orthodontic adhesives (VP 862 and Saga Bond), with a type-II glass ionomer cement (Ketac Fil) as a control. Test specimens in 2 ml deionized water released fluoride over a period of 33 days. Ketac Fil released 54 and 15 times more fluoride than Tetric after 24 h and 1 month, respectively, whereas the two adhesives released amounts between these values. Specimen exposure to 1000-ppm NaF solution increased the 24-h fluoride release from all materials, with near pre-exposure levels reached after 2-3 days. Ketac Fil had a tendency to recharge not seen with the other materials. The ytterbium trifluoride filler in Tetric has a very low water solubility, and it is therefore suggested that the increases in fluoride release from Tetric after exposure to fluoride were most probably due to release of surface-retained fluoride.

Adhesives↗