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Biomedical subjects

M MacDonald

Publications and source records attributed to M MacDonald.

At least 19 recordsLinked to original sources
PubMed2006

A large patient study confirming that facioscapulohumeral muscular dystrophy (FSHD) disease expression is almost exclusively associated with an FSHD locus located on a 4qA-defined 4qter subtelomere.

Facioscapulohumeral muscular dystrophy (FSHD), an autosomal dominant disorder, represents the third most common human muscular dystrophy. The FSHD disease locus, at chromosome 4q35, is associated with large contractions of the polymorphic repeat sequence array D4Z4. In addition to FSHD disease association with large D4Z4 deletions, a biased interaction with a specific 4qter subtelomeric sequence has been described in patients. Two distinct 4qter subtelomeres, defined as types 4qA and 4qB, have been identified and shown to be equally prevalent in the Caucasian population. In almost all 4q35-linked patients with FSHD, however, disease expression only occurs when large D4Z4 deletions are located on 4qA-defined 4qter subtelomeres. Conversely, large D4Z4 repeat contractions situated on 4qB-defined subtelomeres either are not disease-causing or exhibit a greatly reduced disease penetrance. This study was initiated to confirm this direct FSHD disease association data by measuring the frequency of type 4qA-defined and 4qB-defined subtelomeric sequences in a large cohort of 164 unrelated patients with FSHD from Turkey and the UK, all known to have large D4Z4 deletions. An almost complete association was found between large D4Z4 repeat array deletions located on 4qA-defined 4qter subtelomeres and disease expression in our large FSHD patient cohort. The observed failure of probes 4qA and 4qB to hybridise to two patient-derived DNA samples confirms the presence of an additional rare type of 4qter subtelomeric sequence in humans.

Australia↗
PubMed2005

Leprosy acquired by inoculation from a knee injury.

This case study reports on the development of clinical leprosy in a young Caucasian female from a non-endemic country who contracted the disease while living in a leprosy endemic country. In the presentation and discussion, some relevant factors will be reviewed and discussed that may play a role in the transmission, susceptibility and clinical development of the disease.

Adolescent↗
PubMed2003

Divergent strabismus fixus--a case report.

Strabismus fixus is a rare condition and usually is of convergent type in which one or both eyes are anchored in a position of extreme adduction. Convergent type strabismus fixus is considered to be a congenital disorder and a part of congenital extraocular muscle fibrosis syndrome. Villasecca and Martinez described an acquired type of strabismus fixus. Hayashi et al reported that progressive esotropia could develop into the acquired type of convergent strabismus fixus. There are very few reports of divergent strabismus fixus in the literature. It may or may not be accompanied by ptosis or generalized extraocular muscle fibrosis. In our report, a case of divergent type strabismus fixus is described and discussed.

Aged↗
PubMed2001

Effect of progressive benzyl substitution on the conformations of aminocaproic acid-cyclized dipeptides.

The constraint of dipeptides into a beta-turn conformation can be accomplished by linking the two ends of a standard dipeptide with a linker derived from aminocaproic acid (Aca). To elucidate the possibility of using substituted Aca linkers in peptidomimetic design, a series of five macrocycles composed of a monobenzylated Aca linker (containing the benzyl group on each of the five methylene groups of the parent linker) and Gly-Gly were synthesized. The requisite linkers were made by regiochemically controlled ring expansion techniques (for substitution on Aca positions C-3, C-4, or C-5), an Evans alkylation route (for C-2), or by chain extension of L-phenylalanal (for C-6). The solution-phase conformations of the macrocycles were examined by NMR and CD techniques; in addition, crystal structures of the C-4- and C-6-benzyl-substituted linkers were obtained. Four out of the five macrocycles were found to exist with the dipeptide portion taking up either a type II or II' beta-turn conformation, but the Gly-Gly unit in the compound derived from 4-benzyl-Aca did not correspond to one of the standard beta-turn types.

Aminocaproic Acid↗
PubMed2001

Postmodern negotiations with medical technology: the role of midwifery clients in the new midwifery in Canada.

In 1994, after more than a century of uncertain legal status, the Province of Ontario legalized midwifery and incorporated midwives into the formal health care system. Midwifery is now accessible and publicly funded for all women experiencing "normal" uncomplicated pregnancy and birth. Yet midwifery's move from the margins into the mainstream health care system has brought many new challenges. Midwives must now contend with an expanded scope of practice; they use more medical technology both to fulfill their professional obligations and to respond to the choices of women. This and an increased accessibility to a wider clientele seem to work against midwifery as a critical, low-tech alternative to "technocratic birth." In this article, through re-telling and analyzing women's narratives of pregnancy and birth, I explore the role of midwifery clients in re-shaping midwifery's relationship to medical technology. Steering away from essentialist explanations that hold that women are either inherently opposed to technology by virtue of their closeness to nature or wholly oppressed by technology and the systems within which it is imbedded, my analysis focuses on women's agency (on what women do rather than on what is done to them). My study suggests that women act pragmatically both with regard to biomedical technology and to midwifery. I argue that women's negotiations with medical technology have been instrumental in re-shaping midwifery as a postmodern phenomenon.

Biomedical Technology↗
PubMed2001

A tool to assess clinical signs and symptoms of localized infection in chronic wounds: development and reliability.

This paper reports on the development and testing of a tool designed to assess chronic wounds for the clinical signs and symptoms of localized infection. Thirty-one wounds were assessed by two independent nurse observers for the signs and symptoms of infection using the Clinical Signs and Symptoms Checklist. The Clinical Signs and Symptoms Checklist delineates 12 signs and symptoms of infection (i.e., pain, erythema, edema, heat, purulent exudate, serous exudate with concurrent inflammation, delayed healing, discoloration of granulation tissue, friable granulation tissue, pocketing at the base of the wound, foul odor, and wound breakdown) and their definitions. The reliability of each sign or symptom on the checklist was calculated using percent agreement and the Kappa statistic. Percent agreement ranged from 65% to 100%, and Kappa statistics ranged from 0.53 to 1.00, excluding pocketing of the wound base. The reliability estimates obtained for signs and symptoms on the Clinical Signs and Symptoms Checklist compare favorably with other data regarding interclinician agreement on wound assessment. Incorporating a structured approach to assess and monitor for wound infection, such as the Clinical Signs and Symptoms Checklist, may improve clinician skill and accuracy in identifying this condition.

Aged↗
PubMed2000

Synthesis and conformation of Gly-Gly dipeptides constrained with phenylalanine-like aminocaproic acid linkers.

[structure: see text] The constraint of dipeptides with linkers derived from 6-aminocaproic acid (Aca) is a useful means of constructing a beta-turn peptidomimetic. The extension of this concept to the mimicry of a tripeptide entails the incorporation of a side chain moiety on either end of the Aca chain. The synthesis and conformational analysis of two exemplary compounds is discussed.

Aminocaproic Acid↗
PubMed2000

Possible mediation of quinolinic acid-induced hippocampal damage by reactive oxygen species.

Several differences exist between quinolinic acid and N-methyl-D-aspartate (NMDA) in the potency and pharmacology of their neurotoxic actions in the brain, suggesting that quinolinic acid may act by mechanisms additional to the activation of NMDA receptors, possibly involving lipid peroxidation. In the present review, studies are considered which have attempted to determine whether free radicals might contribute to the neuronal damage induced by quinolinic acid. Following Injections into the hippocampus of anaesthetised rats, quinolinic acid induced damage is prevented by melatonin, by an action not blocked by the melatonin receptor blocker luzindole. Deprenyl, but not the non-selective monoamine oxidase inhibitor nialamide, also prevent quinolinic acid-induced damage. In vitro, several groups have shown that quinolinic acid can induce lipid peroxidation of brain tissue The results suggest that free radical formation contributes significantly to quinolinic acid-induced damage in vivo.

Animals↗
PubMed2000

Haemophilia A in a litter of Siberian huskies.

AIM: To investigate haemorrhagic diathesis in several males in a litter of Siberian huskies. METHODS: Activated partial thromboplastin time, prothrombin time, and Factor VIII and Factor IX concentrations were measured in citrated whole blood samples. RESULTS: Males in the litter had decreased Factor VIII concentrations. CONCLUSIONS: Haemophilia A was diagnosed as the cause of haemorrhagic diathesis in several males in a litter of Siberian huskies.

Journal Article↗
PubMed2000

The New York State universal newborn hearing screening demonstration project: ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention.

OBJECTIVE: To determine the ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention through a multi-center, state-wide universal newborn hearing screening project. DESIGN: Universal newborn hearing screening was conducted at eight hospitals across New York State. All infants who did not bilaterally pass hearing screening before discharge were recalled for outpatient retesting. Inpatient screening and outpatient rescreening were done with transient evoked otoacoustic emissions and/or auditory brain stem response testing. Diagnostic testing was performed with age appropriate tests, auditory brain stem response and/or visual reinforcement audiometry. Infants diagnosed with permanent hearing loss were considered for hearing aids and early intervention. Ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention were investigated regarding nursery type, risk status, unilateral versus bilateral hearing loss, loss type, loss severity, and state regions. RESULTS: The prevalence of infants diagnosed with permanent hearing loss was 2.0/1000 (85 of 43,311). Of the 85 infants with hearing loss, 61% were from neonatal intensive care units (NICUs) and 67% were at risk for hearing loss. Of the 36 infants fitted with hearing aids, 58% were from NICUs and 78% were at risk for hearing loss. The median age at identification and enrollment in early intervention was 3 mo. Median age at hearing aid fitting was 7.5 mo. Median ages at identification were less for infants from the well-baby nurseries (WBNs) than for the NICU infants and for infants with severe/profound than for infants with mild/moderate hearing loss, but were similar for not-at-risk and at-risk infants. Median ages at hearing aid fitting were less for well babies than for NICU infants, for not-at-risk infants than for at-risk infants, and for infants with severe/ profound hearing loss than for infants with mild/ moderate hearing loss. However, median ages at early intervention enrollment were similar for nursery types, risk status, and severity of hearing loss. CONCLUSIONS: Early ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention can be achieved for infants from NICUs and WBNs and for infants at risk and not at risk for hearing loss in a large multi-center universal newborn hearing screening program.

Age Factors↗
PubMed2000

The establishment of an industry-based education program in public health.

Commonwealth reforms have led to staff of the Department of Health and Aged Care needing a greater knowledge of public health, to more effectively evaluate evidence and to quickly acquire competence in new emerging areas. The department's requirements of a training program could not be met by existing university-based public health courses. A consortium of five universities and the department worked together to develop an industry-based course that would meet the Commonwealth's needs. The course was constituted within university regulations; had an incremental and articulated structure with exit points at certificate, diploma and Masters levels; was relevant to the work of staff; offered subjects which complemented the staff's existing skills, training and career aspirations; drew upon expertise across the universities; and was flexible in its delivery. The Commonwealth's and universities' experience has been sufficiently positive to conclude that a corporate public health postgraduate program has a place alongside university-based programs.

Australia↗
PubMed1999

The performance of a self-managing day surgery nurse team.

The objective of this study was to assess the validity of the hypothesis that a self-managing nurse team can successfully combine traditional caring, expanded nursing and modern management roles and that morale among team members will be high. The study comprised a 15-month longitudinal case study of eleven members of a day surgery nursing team at a newly established day surgery unit in a district general hospital. The main outcome measures were as follows. Morale: sickness absence statistics, results of staff surveys. Caring role: patient satisfaction survey results. Expanded nurse role: day case activity performance indicators. Management role: financial performance measures. Morale in the day surgery team was higher than average for hospital staff. The results of patient satisfaction surveys were overwhelmingly positive. Day case activity performance improved to that of the top percentile for Scotland. Financial performance targets were exceeded. The day surgery team successfully combined caring, expanded nursing and management roles and staff morale was higher than hospital average.

Absenteeism↗
PubMed1999

Prenatal diagnosis for facioscapulohumeral muscular dystrophy (FSHD).

This study outlines the molecular DNA findings derived from 12 separate prenatal diagnoses offered to families with a history of facioscapulohumeral muscular dystrophy. A high risk of the fetus being affected was identified in five pregnancies. Several practical problems are discussed, particularly those arising from the quality and quantity of DNA made available for molecular diagnosis. Evidence of the 4q35 and 10q26 telomeric exchanges is present in 20 per cent of the general population and the specificity of the test is 95 per cent. The eventual isolation and functional characterization of the FSHD gene should allow us to unravel many of the complexities currently associated with the molecular diagnosis of this disorder.

Chromosomes, Human, Pair 10↗
PubMed1998

MSG1 (melanocyte-specific gene 1): mapping to chromosome Xq13.1, genomic organization, and promoter analysis.

MSG1 (melanocyte-specific gene 1) is a recently isolated gene predominantly expressed in cultured normal melanocytes and pigmented melanoma cells. MSG1 encodes a 27-kDa nuclear protein that has strong intrinsic transcriptional transactivating activity. In this report, the human MSG1 gene was mapped to chromosome Xq13.1 using X chromosome-specific somatic cell hybrids, and the mouse Msg1 gene was mapped 1.9 +/- 1.3 cM proximal to Xist using an interspecific backcross panel. Both the human and the mouse MSG1 genes consist of three exons and two introns within 5 kb of genomic DNA, and their genomic structures are highly conserved. Southern blot analysis suggests the existence of MSG1 homologues in chicken, zebrafish, and Drosophila. A 2.0-kb fragment of the 5'-flanking region of the mouse Msg1 gene contains a TATA box and potential binding sites for several transcription factors including USF, Brn-3, Brn-2, TFE3, Oct-1, AP-2, and Spl. This promoter fragment activates transcription of a reporter gene in pigmented melanoma cells, but not in amelanotic melanoma cells or nonmelanocytic cells, indicating that Msg1 expression is at least partially regulated at the transcriptional level.

Animals↗
PubMed1998

Functional overlap between murine Inpp5b and Ocrl1 may explain why deficiency of the murine ortholog for OCRL1 does not cause Lowe syndrome in mice.

The oculocerebrorenal syndrome of Lowe (OCRL) is an X-linked human genetic disorder characterized by mental retardation, congenital cataracts, and renal tubular dysfunction. The Lowe syndrome gene, OCRL1, encodes a phosphatidylinositol 4,5-bisphosphate 5-phosphatase in the Golgi complex. The pathogenesis of Lowe syndrome due to deficiency of a phosphatidylinositol 4,5-bisphosphate 5-phosphatase in the Golgi complex is unknown. We have used targeted disruption in embryonic stem cells to make mice deficient in Ocrl1, the mouse homologue for OCRL1, as an animal model for the disease. Surprisingly, mice deficient in Ocrl1 do not develop the congenital cataracts, renal Fanconi syndrome, or neurological abnormalities seen in the human disorder. We hypothesized that Ocrl1 deficiency is complemented in mice by inositol polyphosphate 5-phosphatase (Inpp5b), an autosomal gene that encodes a phosphatidylinositol bisphosphate 5-phosphatase highly homologous to Ocrl1. We created mice deficient in Inpp5b; the mice were viable and fertile without phenotype except for testicular degeneration in males beginning after sexual maturation. We crossed mice deficient in Ocrl1 to mice deficient in Inpp5b. No liveborn mice or embryos lacking both enzymes were found, demonstrating that Ocrl1 and Inpp5b have overlapping functions in mice and suggesting that the lack of phenotype in Ocrl1-deficient mice may be due to compensating Inpp5b function.

Amino Acid Sequence↗
PubMed1998

Higher-order suppression in diffraction-grating monochromators using thin films.

Although a continuously tuneable source of photons is a very desirable feature of synchrotron radiation it has one main drawback: the contamination of the photon beam by higher-order diffracted light. Several elements have absorption edges which lie between 10 and 200 eV, a range prone to high second- and third-order content in XUV monochromators. They can, therefore, be used as transmission filters to reduce this higher-order content. This paper describes the use of thin filters to reduce the higher-order content in diffraction-grating monochromators. Their suppression efficiency, transmission and ageing have been characterized using photoelectron spectroscopy and compared with calculated values. The effect of oxide contamination on their performance has been assessed. Filters are now installed on eight XUV beamlines and have been in routine use for several years.

Journal Article↗