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Biomedical subjects

S B Holmes

Publications and source records attributed to S B Holmes.

At least 19 recordsLinked to original sources
PubMed2004

Persistence of extracellular baculoviral DNA in aquatic microcosms: extraction, purification, and amplification by the polymerase chain reaction (PCR).

Genetically-modified baculoviruses have potential uses as bio-pesticides in forestry. However, the baculoviral occlusion bodies (OBs) may release genetically-modified DNA into the forest environment. In this research, outdoor aquatic microcosms, spiked with 673 microg of genomic DNA (4.4 x 10(12) target copies) from the genetically modified baculovirus Choristoneura fumiferana MNPVegt-/lacZ+, were exposed to natural summer conditions. A 530 bp DNA fragment from the genome of CfMNPVegt-/lacZ+ was detected in field microcosm water samples for about 24 h. The introduced DNA may have persisted for a longer time, but was below the detection limit of the PCR analysis (13.5 pg DNA or 8.9 x 10(4) target copies ml(-1) water). The detection limit of PCR was determined by spiking water samples with a dilution series of CfMNPVegt-/lacZ+ genomic DNA, extracting and purifying the DNA, and then PCR analysis. This study provides some of the first information on the persistence and detection limits of this viral DNA under aquatic ecological conditions, and the methods that can be used to conduct such a molecular-based field study.

Baculoviridae↗
PubMed2004

Extraction, detection and persistence of extracellular DNA in forest litter microcosms.

A DNA extraction method was developed that preferentially extracted extracellular DNA rather than intracellular DNA from forest litter. The method purposely avoided the use of harsh chemicals and physical disruption steps used in total DNA extraction to release DNA from cells. The detection limit of PCR, determined by spiking forest litter samples with a dilution series of Choristoneura fumiferana MNPVegt(-)/lacZ(+) genomic DNA, was about 1 ng DNA or 6.85 x 10(6) target copies 0.5 g(-1) moist forest litter or 0.14 g(-1) dry forest litter. In this study, outdoor terrestrial microcosms, each spiked with 49.2 microg of genomic DNA (from the baculovirus CfMNPVegt(-)/lacZ(+)), were exposed to summer conditions. A 530 bp DNA fragment from the genome of the baculovirus CfMNPVegt(-)/lacZ(+) was detected in these microcosms for about 3 months. The DNA may have persisted for a longer period but was below the detection limit of the PCR analysis.

Animals↗
PubMed2001

Extraction and detection of baculoviral DNA from lake water, detritus and forest litter.

AIMS: This paper describes a quick, reproducible, sensitive method for baculoviral DNA extraction, purification and detection from freshwater and forest litter environments. METHODS AND RESULTS: The extraction protocol utilizes enzymatic and chemical lysis and physical disruption. To assess the efficiency of the extraction and purification protocol, PCR was used to detect a 530 bp DNA fragment from the genome of a genetically-modified baculovirus, Choristoneura fumiferana NPVegt-/lacZ+. The detection limit of PCR amplification was routinely about 4.1 x 102 occlusion bodies (OBs) 450 microl-1 lake water. Template DNA from the detritus and forest litter samples required 100-fold dilutions before use in PCR reactions. The detection limits for detritus and forest litter samples were routinely about 7.41 x 103 and 2.08 x 104 OBs 0.5 g-1 dry weight, respectively. CONCLUSION: The DNA extraction and purification methodology is reproducible, sensitive and can be used in lieu of, or in conjunction with, insect bioassays. SIGNIFICANCE AND IMPACT OF THE STUDY: The DNA extraction and purification protocol described in this paper will facilitate risk assessment and ecological studies of both wild-type and genetically-modified baculoviruses.

Baculoviridae↗
PubMed2001

Percutaneous osteosynthesis of the zygomatic buttress.

We describe a technique of percutaneous miniplate osteosynthesis of the zygoma, using the transbuccal approach. It can be used in conjunction with an extraoral approach, or in isolation. Excellent access was achieved to the posterior zygomatic buttress and arch of zygoma, and the infraorbital rim. No complications developed in the two cases presented. This technique is a useful addition to the armamentarium of maxillofacial surgeons.

Adult↗
PubMed1999

Hyponatraemia and seizures after ecstasy use.

A patient presented to our unit with seizures and profound hyponatraemia after ingestion of a single tablet of ecstasy. The seizures proved resistant to therapy and ventilation on the intensive care unit was required. Resolution of the seizures occurred on correction of the metabolic abnormalities. The pathogenesis of seizures and hyponatraemia after ecstasy use is discussed. Ecstasy use should be considered in any young patient presenting with unexplained seizures and attention should be directed towards electrolyte levels, particularly sodium.

Adult↗
PubMed1997

Infectivity and effects of gypsy moth and spruce budworm nuclear polyhedrosis viruses ingested by rainbow trout.

Rainbow trout fingerlings were fed dried krill injected with gypsy moth or spruce budworm nuclear polyhedrosis virus (LdNPV and CfNPV, respectively) at a total dose of 1.4 x 10(7) occlusion bodies (OBs) per fish. By the end of the 21-day experimental period there were no adverse effects on fish survival or behavior and no significant differences in feeding rates or growth between treated and control fish. The internal organs of all fish were examined at the end of the experiment and there were no signs of lesions, discoloration, swelling, hemorrhaging, or other aberrations. Visceral tissues were analyzed with a horseradish peroxidase-labeled whole genomic DNA probe (enhanced chemiluminescence procedure) to detect infection by the NPVs. There were no indications of NPV infection (no positive signals) in stomach and intestinal tract tissues of treated fish. High background signals were obtained from liver samples, but further analyses indicated that these were not due to the presence of LdNPV or CfNPV. The protocols outlined here should be applicable to determining infectivity and effects of genetically modified insect viruses on fish.

Animals↗
PubMed1995

Comparison of forest soil microcosm and acute toxicity studies for determining effects of fenitrothion on earthworms.

The effects of the organophosphate pesticide fenitrothion on Eisenia fetida Savigny and Dendrobaena octaedra Savigny were studied using the OECD acute toxicity test and microcosms containing forest organic matter. In the acute toxicity study, both species were relatively susceptible to fenitrothion, although D. octaedra (LC50 = 393.9 ml/cm2) was approximately eight times more sensitive than E. fetida (LC50 = 54.1 ml/cm2). E. fetida was unable to utilize oak/maple litter for growth, and attempts to use this species in microcosms were abandoned. In microcosm studies, reproduction of D. octaedra was affected at the expected environmental concentration (EEC), whereas growth and maturation rates did not decrease until 100x the EEC was used. Even at 100x EEC, a significant effect on survival of D. octaedra in microcosms was not demonstrated. The use of microcosm studies to provide insight into possible ecological effects of pesticides is discussed.

Animals↗
PubMed1994

Attitudes about autopsy: implications for educational interventions.

Although the role of autopsy in confirming diagnoses and advancing research is well documented, family members are inadequately informed about the procedure. The present study examined attitudes about autopsy among older adults. Focus group interviews were conducted with members of three caregiver support groups and two senior centers. Predominant themes included: benefits, barriers, religious views, and concerns about procedures. Results suggest the need to design educational interventions to: (a) involve family members in advance planning; (b) provide counseling regarding the purpose, process, and procedures of autopsy; and (c) facilitate communication skills and awareness of local autopsy services and policies among physicians.

Autopsy↗
PubMed1994

Effects of lethal and sublethal concentrations of the herbicide, triclopyr butoxyethyl ester, in the diet of zebra finches.

Lethal and sublethal effects of dietary triclopyr butoxyethyl ester (TBEE) on zebra finches (Poephila guttata Gould) were determined in laboratory experiments conducted between 8 January and 1 May 1991. The 8-day median lethal dietary concentration, LC50 (95% confidence interval), of TBEE to zebra finches was 1,923 (1,627 to 2,277) mg/kg. In the sublethal effects experiment, when birds were exposed to 500 mg/kg TBEE in the diet for 29 days, food consumption and body weight were significantly depressed (P < 0.05). Similar prolonged exposures to 50 and 150 mg/kg TBEE in the diet had no significant effect on food consumption or body weight (P > 0.05). Perch-hopping activity was depressed relative to controls in the 500 mg/kg group, and elevated in the 150 mg/kg group, but neither of these differences was significantly (P > 0.05). Disappearance of TBEE residues from treated seeds over the 29 day experimental period followed an exponential decay model, with half-lives in the order of 15 to 18 days. On the basis of our observation that TBEE had no significant adverse effects at a concentration greater than the maximum expected environmental concentration, we propose that forestry applications of triclopyr at registered dosage rates pose little risk to wild songbirds.

Analysis of Variance↗
PubMed1994

Increasing coordination of the dementia service delivery network: planning for the Community Outreach Education Program.

Dementia is an emerging public health concern because of its prevalence and the cost and extent of care typically needed for people with cognitive disorders. When family members seek assistance in providing care, they frequently encounter a fragmented service delivery network. To increase the coordination of services for people with dementia, the Community Outreach Education Program (COEP) has been designed to provide educational interventions to disseminate information about the diagnosis, assessment, management, and treatment of dementia to health care professionals, service providers, staff of volunteer and community organizations, and family members. This article describes plans for the COEP within the context of a community development perspective.

Aged↗
PubMed1993

Pathologists' participation in postmortem examinations for patients with dementia.

Pathologists (n = 571) in Michigan were surveyed to examine the problem of limited access to autopsy experienced by families of patients with dementia and to assist with the implementation of the Michigan Dementia Program. The survey determined the extent to which pathologists performed autopsies for patients with dementia and/or were willing to do so as part of a statewide Postmortem Examination Program. Responses from 394 pathologists (69%) indicated that 49% were willing to perform brain removal and 44% were interested in learning more about the statewide program. The survey results were used to recruit pathologists, to identify potential problems, and to provide baseline data against which to measure the effects of a fully implemented program.

Attitude of Health Personnel↗
PubMed1993

Services for persons with dementia and their families: a survey of information and referral agencies in Michigan.

In planning a statewide Dementia Program, Michigan agencies (N = 244) providing geriatric information and referral (I&R) were surveyed to determine service availability, families' needs, and problems providing I&R for persons with dementia and their families. Home-delivered meals, nursing and social work assessments were considered more available. Medical assessment, however, was considered "very available" by only 60%. Respite and adult day care were least available and most needed. Least was known about autopsy and financial services. For several services, non-urban areas reported less availability than urban areas. With additional information and training, existing agencies could provide more available and extensive I&R for persons with dementia and their families, forming a statewide network.

Data Collection↗
PubMed1992

An interlaboratory comparison of data on brain cholinesterase activity in forest songbirds exposed to aerial application of Zectran.

Zectran (4-dimethylamino-3,5-xylyl N-methyl-carbamate), a carbamate insecticide (active ingredient [AI] mexacarbate), was aerially applied to two 300 ha plots of coniferous forest at dosage rates of 70 and 140 g AI/ha, respectively. The brains of 288 birds collected from the treated areas and 84 birds from untreated areas were sagittally sectioned into approximately equal halves. Each of the laboratories participating in the study, the Forest Pest Management Institute (FPMI) and the Canadian Wildlife Service, Atlantic Region (CWS), assayed one half of each brain for cholinesterase (ChE) activity and the results were compared. The ChE estimates of the two laboratories on half brains from the same birds were poorly correlated (R = 0.136, P less than 0.05) and differed significantly (P less than 0.00005). The reasons for this are uncertain. Despite the discrepancy in ChE estimates, however, separate statistical analysis of each data set produced the same general conclusion: the ChE response to Zectran exposure was statistically significant but biologically unimportant. In both data sets, statistically significant ChE responses by niche and time since spraying were found. The dosage rate emitted from the airplane was a better predictor of ChE activity in the canopy niches than was volume deposited at ground level, but volume deposited was a more useful predictor for ground birds in most situations. These results are discussed in the context of a proposal to develop a reference file of normal brain ChE activities of common wildlife species.

Acetylthiocholine↗