PubMed Health⌕ Search

Biomedical subjects

M O'Shaughnessy

Publications and source records attributed to M O'Shaughnessy.

At least 19 recordsLinked to original sources
PubMed2004

The metabolism of cyclamate to cyclohexylamine in humans during long-term administration.

A group of 14 subjects, who had been identified from 261 volunteers in a 1-week screen as being able to metabolize the sweetener cyclamate to cyclohexylamine (>0.2% of a daily dose), and 31 nonconverters (<0.2% metabolism) were given calcium cyclamate tablets (equivalent to 250 mg cyclamic acid, 3 times daily) for a period of 13 weeks. The metabolism of cyclamate to cyclohexylamine was determined using twice-weekly timed (3 h) urine collections during week 1-3 and 7-13. Urine specimens were collected on all other study days to investigate day-to-day fluctuations in cyclohexylamine excretion. Analyses of the twice weekly timed urine collections showed that subjects recruited as nonconverters essentially remained nonconverters. Of the converters, three showed consistently low metabolism, five showed erratic metabolism, five showed low metabolism initially, which increased during the latter part of the study, and one subject showed consistently high metabolism throughout the study. Analysis of the day-to-day urine specimens showed marked intrasubject variability. The plasma concentrations of cyclohexylamine measured on weeks 1-3 and 7-13 reflected the urine profiles. The highest individual long-term average steady-state excretion values based on the 3-h urine collections and daily samples were 21%, 23%, 25%, 29%, 34%, and 38%. The maximum % metabolism detected in the high converters occasionally reached the value of 60% reported in previous short-term studies, but this high activity was not maintained, and was followed by periods of lower metabolism. The results of this metabolism study support an acceptable daily intake (ADI) of 0-11 mg/kg body weight per day.

Adult↗
PubMed2001

Endothelial nitric oxide synthase gene-deficient mice demonstrate marked retardation in postnatal bone formation, reduced bone volume, and defects in osteoblast maturation and activity.

Nitric oxide (NO) has been implicated in the local regulation of bone metabolism. However, the contribution made by specific NO synthase (NOS) enzymes is unclear. Here we show that endothelial NOS gene knockout mice (eNOS-/-) have marked abnormalities in bone formation. Histomorphometric analysis of eNOS-/- femurs showed bone volume and bone formation rate was reduced by up to 45% (P: < 0.01) and 52% (P: < 0.01), respectively. These abnormalities were prevalent in young (6 to 9 weeks old) adults but by 12 to 18 weeks bone phenotype was restored toward wild-type. Dual energy X-ray absorptiometry analysis confirmed the age-related bone abnormalities revealing significant reductions in femoral (P: < 0.05) and spinal bone mineral densities (P: < 0.01) at 8 weeks that were normalized at 12 weeks. Reduction in bone formation and volume was not related to increased osteoclast numbers or activity but rather to dysfunctional osteoblasts. Osteoblast numbers and mineralizing activity were reduced in eNOS-/- mice. In vitro, osteoblasts from calvarial explants showed retarded proliferation and differentiation (alkaline phosphatase activity and mineral deposition) that could be restored by exogenous administration of a NO donor. These cells were also unresponsive to 17ss-estradiol and had an attenuated chemotactic response to transforming growth factor-beta. In conclusion, eNOS is involved in the postnatal regulation of bone mass and lack of eNOS gene results in reduced bone formation and volume and this is related to impaired osteoblast function.

Absorptiometry, Photon↗
PubMed2000

Squamous cell carcinoma of the finger masquerading as an abscess. Case report.

A 43-year-old man presented with an abscess on his left ring finger, which recurred despite multiple drainage procedures. Histological examination of the lesion was unhelpful; it was only on histopathological examination of the finger after ray amputation that the diagnosis of cutaneous squamous cell carcinoma was established. This case illustrates the need to consider malignancy when dealing with chronic finger infections.

Abscess↗
PubMed2000

Effects of a silicone-coated polyamide net dressing and calcium alginate on the healing of split skin graft donor sites: a prospective randomised trial.

An open randomised prospectively controlled trial was performed to assess the healing efficacy, slippage rate and degree of discomfort on removal of calcium alginate and a silicone-coated polyamide net dressing on split skin graft donor sites. Sixteen patients were randomised to the calcium alginate group and 14 to the silicone-coated group. The donor sites were assessed at days 7, 10, 14 and up to day 21. The mean time to healing in the calcium alginate group was 8.75 +/- 0.78 days (range 7 to 14 days) compared to 12 +/- 0.62 days (range 7 to 16 days) for the silicone-coated group (p < 0.01). Although more silicone-coated dressings slipped (5 versus 1), the difference was not statistically significant. Pain during the first dressing change was assessed using a visual analogue pain scale. Although no significant differences were found between the groups, it was necessary to change the dressing protocol in the silicone-coated arm of the trial after entering the first two patients. Overlaid absorbent gauze adhered to the donor site through the fenestrations in the dressing necessitating the placement of paraffin gauze between the experimental dressing and the overlying cotton gauze. There was one infection in the study, occurring in the alginate group. Based on these results we recommend calcium alginate as the dressing of choice for split skin graft donor sites.

Adult↗
PubMed1999

Antiretroviral therapy: 'the state of the art'.

The field of antiretroviral therapy is evolving at a very rapid pace. At this time, the initiation and optimization of antiretroviral therapy is based on serial plasma viral load determinations which aim to suppress viral replication to as low as possible for as long as possible, thus preventing disease progression. Currently available antiretrovirals require combination therapy with at least three agents to achieve this goal. Increasing availability of newer and more potent antiretroviral regimens will continue to enhance and simplify the number of therapeutic options available in the not too distant future.

Anti-HIV Agents↗
PubMed1999

Toronto street youth and HIV/AIDS: prevalence, demographics, and risks.

PURPOSE: The purposes of this study were: (a) to identify human immunodeficiency virus (HIV) prevalence in Toronto street youth through paired blood and saliva specimens; (b) to identify the HIV risk and prevention behaviors of street involved youth; and (c) to identify demographic or other factors that may contribute to the risk of street youth becoming infected with HIV/acquired immunodeficiency syndrome (AIDS) in the future. METHODS: This was a cross-sectional convenience study of street-involved youth aged 14-25 years. The youth participated in interviews to identify HIV-related knowledge and personal risk and preventive behaviors. Following interviews, they were asked to provide a saliva sample, blood spot, or both. They could refuse one or both samples without jeopardizing their involvement or receiving an honorarium. Two males were the only participants who declined to provide a sample. RESULTS: Fifteen of 695 (2.2%) youth tested positive for HIV infection. All were male, ranging in age from 18 to 25 years. Same and opposite sex, intravenous (IV) drug use, prostitution, and incarceration were risk factors associated with positive HIV test results. The rate of HIV infection was seven times greater for the group 20 years of age and older (20-25) compared to the younger group aged 14-9 years. The proportion testing positive for HIV from small cities, towns, and rural communities in Ontario was 40%; yet, they represented 21% of the study population. Most (57%) youth had been on their own for no more than 3 years and had moved frequently. Nearly two thirds (60%) had stayed in hostels or homeless shelters in the previous 6 months. CONCLUSION: Street youth in Canada are at high risk of HIV infection with their risk increasing with age. Unprotected (same and opposite) sex, IV drug use, prostitution and incarceration were linked to their HIV infections. The high level of mobility identified by street youth challenges governments, communities, and public health officials to develop appropriate prevention strategies and to carefully monitor the spread of HIV infection in this vulnerable population.

Adolescent↗
PubMed1999

Developmental regulation of nitric oxide synthase expression in rat skeletal bone.

Nitric oxide (NO) has been implicated in bone growth and remodeling by studies showing that inhibition of NO-synthase (NOS) activity retards normal gain in bone mineral density both during skeletal development and after sexual maturity. In the present study, we aimed to assess the level of expression and cellular localization of the three NOS isoforms during skeletal bone development from neonatal to sexual maturity in female Wistar rats. Reverse transcription polymerase chain reaction (RT-PCR) was used to analyze the presence of NOS1 (neuronal), NOS2 (inducible), and NOS3 (endothelial) transcripts in femoral bone from neonatal, 4-, 8-, and 12-week-old rats. RT-PCR amplified NOS1, NOS2, and NOS3 transcripts of 472-, 807-, and 289-bp, respectively. There were no detectable differences in the levels of NOS1 mRNA between the groups; however, NOS2 mRNA was more abundant in the neonatal group compared with 4-, 8-, and 12-week groups. Expression of NOS1 protein could not be detected in bones by either Western blotting or immunocytochemistry in any of the age groups investigated. Western blots for NOS2 revealed expression in the neonatal group only and it was not detected in any of the older age groups. Immunostaining for NOS2 was also most evident in the neonatal group and was localized specifically to trabecular osteoblasts and osteoclasts. In all age groups studied, NOS3 mRNA and protein were found in bone-resorbing osteoclasts, cuboidal active osteoblasts, and osteocytes. Semiquantitative RT-PCR provided evidence of down-regulation of NOS3 transcripts during the skeletal development. This was confirmed using in situ hybridization, which showed higher expression in neonatal and 4-week groups than in other groups. Western blots and counting the ratio of trabecular osteoblasts that were NOS3 immunoreactive showed parallel down-regulation of NOS3 protein during skeletal development. Taken together, these data show that there is regulation of NOS2 and in particular NOS3 expression during skeletal development and this may be significant to trabecular bone growth and remodeling.

Animals↗
PubMed1999

Use of incentives to increase compliance for TB screening in a population of intravenous drug users. Vancouver Injection Drug Use Study Group.

SETTING: Intravenous drug users (IDUs) represent a high risk group for dual human immunodeficiency virus (HIV) and tuberculosis (TB) infection. Screening with TB skin testing has therefore been suggested in this group. Subjects' compliance for returning to have TB skin test results read is a major problem. In the setting of a needle exchange program we evaluated the role of financial incentives to increase compliance. METHODS: We evaluated the role of giving a small financial incentive of Can $5 to subjects if they returned to have their purified protein derivative (PPD) skin test read. IDUs who had previously been skin-tested were compared with IDUs drawn from a similar population who, prospectively, were offered a financial incentive. RESULTS: During the initial period 558 subjects were evaluated and no incentive was offered. During the second phase of the study 549 IDUs were assessed but were also offered Can $5 if they returned to have their skin test read. Use of incentives increased compliance from 43% to 78% (P = 0.001). During the same period three active cases of TB were also diagnosed. CONCLUSIONS: We suggest that use of financial incentives can increase the return of IDUs to have their skin tests read. Further studies are required to assess the efficacy of follow-up interventions, especially the use of isoniazid chemoprophylaxis.

Adult↗
PubMed1998

Construction of single-chain antibodies that bind an overlapping epitope of HIV-1 Nef.

The light and heavy chain variable regions of three mouse hybridoma cell lines (AG11, AE6 and EH1) that produce monoclonal antibodies against an overlapping epitope at the C-terminus of Nef were cloned. Sequence analysis of the light and heavy chain variable regions indicated that clones AG11 and AE6, but not EH1, were highly related. Single-chain antibodies were constructed from the cDNA clones of AG11 and EH1, and subcloned into an eukaryotic expressing vector with the green fluorescent protein as marker for expression. Such intracellular antibodies may provide a way in which to inhibit the function of Nef during HIV-1 infection of cells.

Amino Acid Sequence↗
PubMed1998

Active immunization of patients with HIV infection: a study of the effect of VaxSyn, a recombinant HIV envelope subunit vaccine, on progression of immunodeficiency.

Infection with the human immunodeficiency virus (HIV) leads to a progressive immunodeficiency characterized by decreasing levels of CD4+ T lymphocytes. VaxSyn, a vaccine based on the recombinant envelope glycoprotein subunit (rgp160) of HIV-1IIIB, was used to immunize HIV-infected patients to determine whether its administration was beneficial with respect to slowing disease progression. A 3-year multicenter, randomized, placebo-controlled, double-blinded, efficacy and safety trial of repeated immunization with VaxSyn was used to evaluate the long-term impact on the progression of immunodeficiency. VaxSyn in alum, or alum alone, was given to 278 HIV-infected asymptomatic individuals with initial CD4 counts of > or =500 cells/mm3. Clinical findings, the CD4 count, and both virological and immunological parameters were followed. No significant differences were observed between the treatment and placebo control groups in rate of CD4 T cell decline, time to initiation of antiretroviral therapy, incidence of opportunistic infections, HIV RNA plasma viremia, HIV viral infectivity as measured by quantitative HIV coculture assay, and death. This study revealed no effect on either clinical or laboratory virological parameters from the administration of VaxSyn.

AIDS Vaccines↗
PubMed1998

Bilateral spontaneous rupture of flexor digitorum profundus tendons.

Spontaneous tendon rupture is an unusual condition usually associated with underlying disease processes such as rheumatoid arthritis, chronic renal failure or bony abnormalities of the hand. We report a case of spontaneous, non-concurrent bilateral rupture of flexor profundus tendons in an otherwise healthy individual. Treatment was successful and consisted of a two-stage reconstruction of the ruptured tendon.

Adult↗
PubMed1998

Is there still a role for traditional methods in the management of fractures of the zygomatic complex?

With the introduction of low-profile mini-plating systems, a trend has developed towards open reduction and rigid internal fixation (ORIF) of fractures of the cranio-facial skeleton. The current policy for management of zygomatic fractures in our unit is to attempt primary reduction by traditional methods, and proceed to ORIF in the event of unsatisfactory fracture stability or alignment. Over a one-year period, 109 patients underwent surgical correction of fractures of the zygomatic complex. Standard Gilles' elevation was performed in 71 cases, percutaneous elevation in three cases, and ORIF was performed in 35 cases. Mean follow-up was 190 days. One case of persistent infraorbital step and three cases of residual malar flattening were documented in patients who underwent Gilles or percutaneous elevation. Morbidity associated with ORIF was minimal. We conclude that while ORIF of zygomatic fractures may offer better results than traditional methods in the management of complex fractures, traditional methods still have a role to play in less complex fractures.

Accidental Falls↗
PubMed1998

An anomalous muscle in the hand.

An anomalous muscle crossing the wrist joint is described. The morphology and clinical relevance of this and other unnamed muscles occurring at the wrist are discussed.

Adult↗
PubMed1998

A study of suicide and attempted suicide by self-immolation in an Irish psychiatric population: an increasing problem.

In the Western World self-immolation is an uncommon but dramatic method of attempting suicide. In-patients who attempt suicide by fire-setting tend to be female with severe psychopathology. In a previous study from the South of Ireland, seven cases from a psychiatric and prison population were identified in a five year period from 1984 to 1989. This would represent an annual rate of 1.07 per cent of burns treated in the burns unit at Cork University Hospital. In this study 12 cases were identified for the years 1994 and 1995. This represents an increase of 3.5 per cent from 1.07 to 4.6 per cent of all burns treated at the same institution. Ten of these patients had a previous psychiatric history and eight of them were resident on a psychiatric ward when they committed the act. Seven of the patients were found to have a high degree of suicide intent of whom four died of their injuries, which gives a mortality rate for this group of 33 per cent. Effective prevention policies are necessary if this increasing problem is to be curtailed.

Adult↗
PubMed1998

Relation between hospital HIV/AIDS caseload and mortality among persons with HIV/AIDS in Canada.

OBJECTIVE: To assess the relation between HIV/AIDS hospital caseload and mortality in Canada. DESIGN: Descriptive, population-based study. SETTING: All hospitals in Canada that admitted any patients with HIV or AIDS between Mar. 31, 1987, and Apr. 1, 1994. PATIENTS: All patients with a diagnostic code on their hospital discharge abstract for HIV infection, AIDS, or with positive serological or viral culture findings for HIV (International Classification of Diseases, 9th revision, 042, 043, 044 or 795.8). MAIN OUTCOME MEASURE: In-hospital mortality. RESULTS: Over the study period, 38,075 admissions attributed to HIV/AIDS (33,380 of men and 4695 of women) were recorded in 513 Canadian hospitals. Of these hospitals, 230 (45%) had fewer than 1 admission per year of patients with HIV/AIDS; 200 (39%) had between 1 and 9; 68 (13%) had between 10 and 99; and 15 (3%) had 100 or more. HIV/AIDS-related admissions ending in death were independently associated with the patient being admitted to lower-volume hospitals, being hospitalized for longer periods of time, and being older, male and at a more advanced stage of disease. During the study period, hospitals with 100 or more admissions per year reported 36% lower mortality among patients with HIV/AIDS than those that had fewer than 1 admission per year. CONCLUSION: There is an inverse relation between hospital caseload and in-hospital mortality among patients with HIV/AIDS in Canada. We attribute this association at least in part to the propensity of high-volume hospitals to deal more effectively with seriously ill patients with HIV/AIDS.

Acquired Immunodeficiency Syndrome↗