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Biomedical subjects

J Skelly

Publications and source records attributed to J Skelly.

At least 19 recordsLinked to original sources
PubMed2001

Ozone exposure thresholds and foliar injury on forest plants in Switzerland.

Canton Ticino in southern Switzerland is exposed to some of the highest concentrations of tropospheric ozone in Europe. During recent field surveys in Canton Ticino, foliar symptoms identical to those caused by ozone have been documented on native tree and shrub species. In Europe, the critical ozone level for forest trees has been defined at an AOT40 of 10 ppm.h O3 (10 ppm.h accumulated exposure of ozone over a threshold of 40 ppb) during daylight hours over a six-month growing season. The objective of this study was to determine the amount of ambient ozone required to induce visible foliar symptoms on various forest plant species in southern Switzerland. Species were grown within eight open-top chambers and four open plots at the Vivaio Lattecaldo Cantonal Forest Nursery in Ticino, Switzerland. Species differed significantly in terms of the ppb.h exposures needed to cause visible symptoms. The most to least symptomatic species grown within open-plots in this study rank as Prunus serotina, Salix viminalis, Vibrnum lantana, Rhamnus cathartica, Betula pendula, Rumex obtusifolius, Sambucus racemosa, Morus nigra, Prunus avium, Fraxinus excelsior, Rhamnus frangula, Alnus viridis, Fagus sylvatica and Acer pseudoplatanus. Similar rankings were obtained in the non-filtered chamber plots. The ranking of species sensitivity closely follows AOT values for the occurrence of initial symptoms and symptom progression across the remainder of the exposure season. Species that first showed evidence of foliar injury also demonstrated the most sensitivity throughout the growing season, with symptoms rapidly advancing over ca. 25-30% of the total plant leaf surfaces by the end of the observation period. Conversely, those species that developed symptoms later in the season had far less total injury to plant foliage by the end of the observation period (1.5 to < 5% total leaf area injured). The current European ambient ozone standard may be insufficient to protect native plant species from visible foliar injury, and many more native species may be sensitive to ozone-induced foliar injury than are currently known.

Environmental Monitoring↗
PubMed1997

DT diaphorase exists as a dimer-tetramer equilibrium in solution.

The quaternary behaviour of DT diaphorase in solution has been investigated by hydrodynamics under a range of conditions. At neutral pH DT diaphorase is shown to exist as a tightly-associated homodimer in a dimer-tetramer equilibrium. Concentrations of the chaotropic agent potassium thiocyanate (KSCN) of greater than 200 mM result in irreversible loss of the FAD cofactor and denaturation of the homodimer though this agent appears to be ineffective in disrupting intermolecular association. These data conform to a model in which under extreme dissociation conditions, the folded dimer is in equilibrium with the unfolded monomer and are consistent with evidence from the X-ray structure and proposed catalytic mechanism where both monomers are catalytically interdependent.

Animals↗
PubMed1997

Disease management interventions to improve outcomes in congestive heart failure.

This study is part of a planned 24-month, multicenter, longitudinal comparison of a comprehensive congestive heart failure (CHF) disease management program and was designed to determine effectiveness after 12 months of implementation. The impact of interventions such as telemonitoring of patients, post-hospitalization follow-up, and provider education on selected primary outcomes (hospital admission and readmission rates, length of stay, total hospital days, and emergency room utilization) in a managed care setting was evaluated. Subjects in the study included all participants in the managed care plan, as well as 149 selected program participants. The effects of the program were analyzed for pure CHF and CHF-related diagnoses, with outcomes for the third quarter of 1996 (postintervention follow-up) being compared with those for the third quarter of 1995 (preintervention baseline). Overall, the data demonstrated significantly reduced admission and readmission rates for patients with the pure CHF diagnosis. Among the entire CHF patient population, the third quarter admission rate declined 63% (P = 0.00002), and the 30-day and 90-day readmission rates declined 75% (P = 0.02) and 74% (P = 0.004), respectively. Among program participants with pure CHF diagnoses, the 30-day readmission rate was reduced to 0, and an 83% reduction occurred for both the third quarter admission (P = 0.008) and 90-day readmission (P = 0.06) rates. In addition, the average length of stay for patients with CHF-related diagnoses was significantly reduced among both plan participants (P = 0.03) and program participants (P = 0.001). Reductions were also seen in total hospital days and emergency room utilization. These data thus indicate that a comprehensive disease management program can reduce healthcare utilization not only among CHF patients in the program but also among the entire managed care plan population.

Disease Management↗
PubMed1995

Urinary incontinence associated with dementia.

Urinary incontinence is common in patients with dementia and is more prevalent in demented than in nondemented older individuals. It occurs with equal or greater frequency in males than in females, and this contrasts with the female preponderance in community-based, general older populations. Since the etiology of incontinence in dementia is multifactorial, a comprehensive assessment of factors within and outside the lower urinary tract is essential. A careful clinical evaluation is sufficient to guide treatment in most cases. Further research is needed to determine the role of simple cystometry and more complex urodynamic investigation in these patients. Research on the management of urinary incontinence in demented patients has focused almost exclusively on toileting programs and drug treatments for detrusor hyperactivity. To date, anticholinergic and antispasmodic medications have not been shown to be effective in treating incontinence in demented persons. However, the few studies undertaken have been in the most severely mentally and physically deteriorated patients, and it is possible that these medications have greater efficacy in less impaired individuals. Prompted voiding regimens have been shown to reduce incontinence by an average of 32% and appear to be a useful approach in managing incontinence in some of these patients. However, unless staff management systems are employed, staff compliance with these programs diminishes with time and the labor costs involved may limit their applicability in nursing homes. Patients who are the most severely cognitively impaired, least mobile, and have the greatest frequency of incontinence derive the least benefit from toileting programs, and palliative measures may be more appropriate in these cases.

Aged↗
PubMed1994

The use of mechanically elicited electromyograms to protect nerve roots during surgery for spinal degeneration.

STUDY DESIGN: This study investigated the use of mechanically elicited electromyograms during the placement of pedicle screws in 89 patients undergoing surgery for spinal stenosis. SUMMARY OF BACKGROUND DATA: Several methods for monitoring nerve roots are available. However, mechanically elicited electromyograms may be more sensitive to mechanical irritation of nerve roots by pedicle screws than by other methods. METHODS: Mechanically elicited electromyograms were recorded in muscle groups innervated by cervical or lumbar nerve roots. Confirmation of surgical activity with the level of the electromyogram was correlated. RESULTS: Results indicated that mechanically elicited electromyograms are extremely sensitive to nerve root irritation. Compared to other methods, electromyograms are a viable alternative. CONCLUSIONS: Results from this study indicated that mechanically elicited electromyograms are sensitive and specific to nerve root firings and should be considered for use during the dynamic phases of surgery.

Bone Screws↗
PubMed1989

Urinary incontinence: current overview of a prevalent problem.

Urinary incontinence is a prevalent problem affecting elders of both sexes in community and institutional settings. Much of this problem is reversible. Detailed history, physical, and a residual urine test can provide sufficient information to begin treatment. There are three main types of incontinence: (1) stress, which may be alleviated by strengthening the pelvic floor muscles or by surgical intervention; (2) overflow; and (3) urge. These different types may co-exist. If the initial treatment is ineffective, it is recommended that referral be made for expert evaluation and urodynamic investigation.

Aged↗
PubMed1987

Demonstration of papillomavirus structural antigen in human urinary bladder neoplasia.

Clear cells showing characteristic features of koilocytotic atypia were found in 41 (82%) of 50 paraffin sections of urinary bladder tumour. Papillomavirus common structural antigen was detected in seven (14%) of the samples using an avidin-biotin peroxidase staining technique. The results suggest a role for the human papillomavirus in the aetiology of urinary bladder neoplasia.

Aged↗
PubMed1982

Immunogenicity in chimpanzees of experimental hepatitis B vaccines prepared from intact hepatitis B virus, purified polypeptides, or polypeptide micelles.

The immunogenicity of three experimental hepatitis B vaccines was evaluated in chimpanzees. Although no antibody to hepatitis B surface antigen (anti-HBs) was detected in two chimpanzees that received an aqueous polypeptide vaccine subcutaneously, a strong anti-HBs response was observed two and ten weeks, respectively, following challenge with hepatitis B virus. Inoculation of two additional chimpanzees with a micellar preparation of these polypeptides by the intravenous route resulted in anti-HBs production in one of the chimpanzees. Two chimpanzees inoculated subcutaneously with an aqueous vaccine of formalin-inactivated intact hepatitis B virus developed anti-HBs in low titers, but the development of antibody to the hepatitis B core antigen following challenge inoculations suggested that subclinical HBV infections may have occurred despite prior vaccination.

Animals↗
PubMed1981

Hepatitis B polypeptide vaccine preparation in micelle form.

The immunoprophylaxis of hepatitis B is hampered by the lack of a technique for growing hepatitis B virus (HBV) in tissue culture. Plasma from persistently infected individuals, one source of viral antigen, contains characteristic 22-nm spherical particles which share a common antigen (the hepatitis B surface antigen or HBsAg) with the outer envelope of the 42-nm double-shelled DNA virus. Highly purified inactivated 22-nm particles have been shown to be safe and to confer protective immunity against HBV in a recent large-scale clinical trial. We have already described the extraction from the particles of a complex of two proteins which are antigenic determinants of HBV--the polypeptide with molecular weight (MW) between 22,000 and 24,000 (called p23) and the glycosylated polypeptide (called gp28) with MW in the range 26,000--29,000 which is thought to be the glycosylated form of p23. We now report the preparation from this complex of water-soluble protein micelles which may be a suitable basis for a second-generation hepatitis B vaccine.

Animals↗
PubMed1981

The use of markers in immune electron microscopy.

Immune electron microscopy (IEM) cannot be used successfully for structures that do not have recognisable morphology. However, at least some of these structures or components are related antigenically to recognisable antigens or viruses. We have therefore mixed unknown antigens with known markers and looked for the presence of mixed aggregates. The present study examined a low molecular weight subunit of rotavirus and a micellar form of hepatitis B surface antigen. In both cases mixed immune aggregates were found showing that the unknown components had antigens in common with the established virus or antigen.

Antigen-Antibody Complex↗
PubMed1981

Nondetection of infectious hepatitis B virus in a human hepatoma cell line producing hepatitis B surface antigen.

The PLC/PRF/5 human hepatoma cell line producing hepatitis B surface antigen (HBsAg) was studied to determine whether infectious hepatitis B virus (HBV) was also being produced. 2 chimpanzees with no previous exposure to HBV and no serologic markers of past or active HBV infection were inoculated intravenously with 50 ml of either tissue culture supernatant fluid (357 ng/ml HBsAg) or a suspension of cells disrupted by repeated freeze-thaw cycles (57 ng/ml HBsAg). No evidence of HBV infection was detected in either chimpanzee during 6 months of evaluation. This study suggests that the expression of a portion of the HBV genome, when a portion or all of that genome has been incorporated into a host cell, can result in the production of HBsAg without infectious HBV. If it becomes possible to produce a similar expression of this portion of the genome by itself in nonmalignant cells, HBsAg without HBV may be produced in vitro for use in hepatitis B vaccines.

Animals↗
PubMed1981

Induction of cell-mediated immunity to HBsAg polypeptides.

Adult male guinea pigs were immunized with hepatitis B virus polypeptides prepared by Triton X-100 solubilization of purified 22-nm hepatitis B surface antigen (HBsAg) particles. A virus-specific subunit containing both the 28,000 molecular weight glycoprotein and the 23,000 molecular weight protein stimulated both cell-mediated and humoral immunity. A whole-blood-cell transformation assay additionally showed that the 64,000 molecular weight component of HBsAg, previously shown to contain host-specific antigens, also stimulated a cellular response to purified intact HBsAg particles, suggesting the additional presence of virus-specific material in this fraction. Immunization of animals with the 28,000--23,000 molecular weight polypeptides subsequently prepared in micelle form enhanced the demonstration of a cell-mediated reaction after only a single dose of immunogen. The results provide further evidence as to the suitability of HBsAg polypeptides prepared by Triton X-100 solubilization for hepatitis B prophylaxis.

Animals↗
PubMed1980

Hepatitis B surface antigen production as a growth cycle-related terminal event in PLC/PRF/5 hepatoma cells.

The dynamics of hepatitis B surface antigen production of PLC/PRF/5 hepatoma cells were studied using a quantitative radioimmunoassay method. Maximum rates of antigen production were found in nutrient-depleted, non-dividing cultures and were temporally related to cytological changes preceding cell death. These results indicate that antigen production may be cell-cycle related and represent a terminal event.

Carcinoma, Hepatocellular↗