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Biomedical subjects

J Gilbert

Publications and source records attributed to J Gilbert.

At least 73 records · Page 4Linked to original sources
PubMed1999

Construction and validation of four childhood asthma self-management scales: parent barriers, child and parent self-efficacy, and parent belief in treatment efficacy.

This study examined the psychometric properties of four new health belief measures for asthmatic children and their parents. A total of 110 asthmatic children (aged 7-15) and 129 parents (with asthmatic children aged 3-15) responded to a mail-out survey. Evidence for reliability (0.75-0.87) and validity was obtained for measures of Parent Barriers to Managing Asthma, Parent Asthma Self-Efficacy (subscales: attack prevention and attack management), Parent Treatment Efficacy, and Child Asthma Self-Efficacy (subscales: attack prevention and attack management). All measures were correlated in the hypothesized directions with health status, asthma symptoms, and impact of illness on the family.

Adolescent↗
PubMed1998

Relationships among deoxynivalenol, ergosterol and Fusarium exoantigens in Canadian hard and soft wheat.

Soluble extracellular components (exoantigens) from cultures of Fusarium graminearum and F. sporotrichioides were used to produce antisera from chickens for an indirect enzyme immunoassay. This immunoassay was used to estimate Fusarium exoantigen levels in 40 samples of fusarium head blight-infected hard red spring wheat from Manitoba, and in 50 samples of infected soft white winter wheat from Ontario. These wheat samples were also assayed for deoxynivalenol (DON), the predominant Fusarium mycotoxin, and for ergosterol, a metabolite reflecting fungal biomass. Using F. sporotrichioides antisera, the linear correlations between exoantigen level and DON content for the hard and soft wheats had coefficients of 0.80 and 0.76, respectively. With the same antisera, linear correlations between exoantigen level and total ergosterol concentration for the hard and soft wheats had coefficients of 0.66 and 0.81, respectively.

Antigens, Fungal↗
PubMed1998

Pneumatic dilatation is effective long-term treatment for achalasia.

Although pneumatic dilatation (PD) has been an established treatment for achalasia for decades, there is limited information on its long-term clinical efficacy. We have followed up the clinical status of patients having PD with a 30- or 35-mm balloon by one of us (D.O.C.) over a 25-year period. Of 144 patients whose initial records were available for review, 31 could not be contacted. Of the remaining 113 patients, 72 (64%) responded to a questionnaire assessing swallowing status and patient satisfaction, and this forms the basis of this report. There were 32 men and 40 women, with mean age 46 years (range: 17-78); mean length of follow-up since PD was 6.5 years (range: 10 months to 25 years). Success was primarily defined by the need for no additional therapy for achalasia other than one or two PD's. PD was effective long-term treatment in 61/72 patients (85%); only four of these required a second PD over this time interval. There was no significant difference in any of the following parameters between patients with a treatment success or failure: age, sex, size of pneumatic dilator, and duration of symptoms prior to PD. Response was significantly better (P < 0.05) in patients having no prior dilatation (43/47; 91%) than in those in whom another physician had performed prior dilatation (18/25; 72%). In response to the question of whether they would select PD again, 68 patients (94%) responded positively. In conclusion, pneumatic dilatation performed using a consistent technique by an experienced physician is effective long-term therapy for achalasia patients of all ages. Most patients require only one dilatation.

Adolescent↗
PubMed1998

Farm and tractor-related fatalities in children in South Australia.

OBJECTIVE: To analyse the circumstances surrounding farm and tractor-related childhood fatalities in South Australia, to identify potentially dangerous situations and to delineate prevention strategies. METHODS: A retrospective search of files was conducted at the Women's and Children's Hospital Department of Histopathology from 1981 to 1996, and the State Coroner's Office from 1988 to 1996. RESULTS: Fifteen fatalities were identified comprising 11 boys and four girls (age range, 2 years 11 months to 13 years; average, 6 years). Activities prior to death included riding on a tractor/trailer (n=8); playing near a field grain storage bin (n=2); playing near machinery (n=2); sleeping in a car near a burn off (n=1); walking around a dam (n=1) and riding as a passenger on a motorbike (n=1). Causes of death included multiple skull fractures and cerebral damage (n=11), asphyxia (n=2), drowning (n=1) and incineration (n=1). CONCLUSIONS: The most dangerous activity involved children riding unrestrained on tractors; falls resulted in extensive injuries from tractor rear wheels or towed machinery. Allowing children on farms to ride on tractors or machinery only if there is a safe seat with a restraining harness would substantially reduce the number of fatal farm-related childhood injuries in South Australia.

Accidents↗
PubMed1998

Widespread axonal injury in gunshot wounds to the head using amyloid precursor protein as a marker.

In order to determine whether axonal injury (AI) is a factor in cases of penetrating head injury, the brains of 14 patients who died shortly after sustaining a fatal gunshot wound (GSW) to the head were examined, and the presence of AI determined using immunohistochemical staining for amyloid precursor protein (APP). The distribution of AI was mapped throughout the cerebral hemispheres and brain stem. AI was present in all cases in a diffuse distribution distant to the missle track with severe involvement of the brain stem in all cases. There was no axonal APP immunoreactivity in the direct region of the missle track at the point of primary axotomy. The APP-positive AI in these cases is likely to be a mixture of primary and secondary AI as APP immunostaining is unable to distinguish primary AI due to mechanical deformation from AI secondary to hypoxic-ischemic damage.

Adolescent↗
PubMed1998

Amphetamine derivative fatalities in South Australia--is "Ecstasy" the culprit?

OBJECTIVE: To analyze features of a series of fatalities caused by amphetamine-derivative designer drugs marketed as "Ecstasy" in South Australia, and to identify reasons for the recent marked increase in number of these deaths. MATERIALS AND METHODS: Following the death of a 26-year-old woman after alleged ingestion of Ecstasy tablets, a retrospective search of files at State Forensic Science, Adelaide and the South Australian State Coroner's Department was undertaken from February 1992 to January 1997 to identify similar cases. RESULTS: Six fatalities were found, all of which have occurred since September 1995 (M:F ratio, 1:1; age range, 22 to 36 years; average age, 27.7 years). All individuals had histories of recent ingestion of illegal drugs thought to be Ecstasy (methylenedioxymethamphetamine, MDMA) at the time of purchase. Delay occurred in seeking medical attention, despite severe symptoms. Causes of death involved documented hyperthermia in 3 cases (temperatures of 41.5-46.1 degrees C), with features of hyperthermia in one other case, and intracranial hemorrhage in another. Drugs in toxic/lethal amounts identified at postmortem included paramethoxyamphetamine (PMA) in all cases, amphetamine/methamphetamine in 4 cases, and methylenedioxymethamphetamine (MDMA or Ecstasy) in only 2 cases. Interaction with a prescription medication (fluoxetine) may have occurred in 1 case. CONCLUSIONS: The number of deaths due to amphetamine derivatives apparently due to substitution of PMA for MDMA (Ecstasy) have recently increased markedly in Adelaide. Potential users should be warned that PMA has been associated with a much higher rate of lethal complications than other designer drugs, and that no guarantee can be made that tablets sold as Ecstasy are not PMA.

Adult↗
PubMed1998

Artificial buzzing lips and brass instruments: experimental results.

Experimental results of a special artificial trombone player are presented: A mechanical device is a substitute for the musician. Wind instruments, and particularly the brass, are self-sustained oscillators. The oscillations are induced by a mechanical oscillator (the lips of the player) acting as a valve which modulates the flow. Measured mechanical parameters of the artificial buzzing lips for different "embouchures of the player" are presented, and analyzed in connection with the played frequencies obtained for the same "embouchures." The results are obtained with two resonator systems (a mouthpiece alone and a trombone with its mouthpiece).

Humans↗
PubMed1998

Identification of a human immunodeficiency virus type 2 (HIV-2) encapsidation determinant and transduction of nondividing human cells by HIV-2-based lentivirus vectors.

Although previous lentivirus vector systems have used human immunodeficiency virus type 1 (HIV-1), HIV-2 is less pathogenic in humans and is amenable to pathogenicity testing in a primate model. In this study, an HIV-2 molecular clone that is infectious but apathogenic in macaques was used to first define cis-acting regions that can be deleted to prevent HIV-2 genomic encapsidation and replication without inhibiting viral gene expression. Lentivirus encapsidation determinants are complex and incompletely defined; for HIV-2, some deletions between the major 5' splice donor and the gag open reading frame have been shown to minimally affect encapsidation and replication. We find that a larger deletion (61 to 75 nucleotides) abrogates encapsidation and replication but does not diminish mRNA expression. This deletion was incorporated into a replication-defective, envelope-pseudotyped, three-plasmid HIV-2 lentivirus vector system that supplies HIV-2 Gag/Pol and accessory proteins in trans from an HIV-2 packaging plasmid. The HIV-2 vectors efficiently transduced marker genes into human T and monocytoid cell lines and, in contrast to a murine leukemia virus-based vector, into growth-arrested HeLa cells and terminally differentiated human macrophages and NTN2 neurons. Vector DNA could be detected in HIV-2 vector-transduced nondividing CD34(+) CD38(-) human hematopoietic progenitor cells but not in those cells transduced with murine vectors. However, stable integration and expression of the reporter gene could not be detected in these hematopoietic progenitors, leaving open the question of the accessibility of these cells to stable lentivirus transduction.

Antigens, CD34↗
PubMed1998

Correspondence analysis of protein kinase C (PKC) inhibition by bis-basic substituted benzamides.

We describe the synthesis of a novel series of bis-basic substituted benzamides and their relative potency in inhibiting rat brain protein kinase alpha (PKC alpha) activity. None of the compounds inhibited enzyme activity via the catalytic domain but several did via the regulatory domain at 1-5 microM concentrations. Inhibition was comparable to that of several di- and triphenylacrylonitriles and triphenylethylenes. According to a multivariate factor (correspondence) analysis of QSAR descriptors, hydrophobicity (log p) and hydration energy were the most discriminant descriptors, much more so than molecular mass, molar refractivity, polarizability, molecular volume and solvent-accessible surface. Inhibitory activity was correlated with high hydrophobicity and low hydration energy. The higher potency of GL9 (N,N'-oxalyl-bis[(o-amino)[2-(diethylamino)ethyl]-benzamide]) that differed from its congener (GL25) by the presence of an oxamide rather than succinamide moiety was tentatively explained by the greater negative charges associated with the carbonyl groups of its oxamide residue. The higher potency of GL22 (N,N'-tere-phthalyl-bis[(o-amino)[2-(diethylamino)ethyl]-benzamide ] in which an aromatic ring is inserted between two benzamide moieties in para, para' rather than ortho, ortho' positions as in GL23 might be due to a planar conformation facilitating membrane insertion. In conclusion, correspondence analysis is a neat way of highlighting similarities and differences in molecular properties (QSAR descriptors and potency). Therapeutic doses of many classes of drug might interfere with the regulatory domain of PKC alpha if, like our test-compounds, they have basic side-chain(s), high hydrophobicity, low hydration energy, a planar conformation and/or a highly charged reactive (oxamide) moiety.

Animals↗
PubMed1998

Palliative terminal cancer care in community hospitals and a hospice: a comparative study.

BACKGROUND: Despite palliative care being an accepted role of community hospitals, there is little quantitative evidence of the type of care provided. AIM: To obtain quantitative data comparing palliative cancer care provided in 12 community hospitals in 10 towns (approximately 350 medical beds) and in a consultant-led purpose-built hospice (12 beds). METHOD: Retrospective medical and nursing case note analysis over one year of cancer deaths in the former Exeter Health District. RESULTS: A total of 171 community hospital and 116 hospice casenotes were analysed. Hospice patients had significantly different reasons for admission compared with community hospital patients (P < 0.001), with pain and symptom control being more frequent and terminal nursing care less frequent reasons for admission to the hospice. Community hospital length of stay was significantly longer than hospice length of stay (P = 0.002; mean community hospital stay 16 days, mean hospice stay eight days). Symptoms on admission differed significantly. Drug prescribing on admission and at death and indications of active treatment of symptoms were broadly similar. Community hospital patients received more investigations than hospice patients, linked to the observation that around one in ten community hospital patients were admitted for investigation and active treatment. Community hospital medical notes were significantly less likely to meet minimum quality standards than were hospice notes (81/171 vs. 18/116; P < 0.001), with major deficiencies in the areas of examination, progress reporting, and absence of confirmation of death. CONCLUSIONS: This study confirms the role of community hospitals in palliative terminal cancer care. Differences in care between community hospitals and a hospice have been demonstrated that may reflect either different admission populations to each setting or differences in the way care was delivered.

Hospices↗
PubMed1998

Dying from cancer in community hospitals or a hospice: closest lay carers' perceptions.

BACKGROUND: Despite there being around 400 community hospitals in the United Kingdom, there is little published research on the quality of service provided by these hospitals. AIM: To compare the quality of terminal cancer care in community hospitals with a hospice as assessed by patients' closest lay carer (relative or friend). METHOD: Structured interview (or questionnaire based on the interview proforma) with closest lay carers of all patients dying over one year in 12 community hospitals in east Devon and a purpose-built hospice in the city of Exeter. RESULTS: A total of 292 cases (176 in community hospitals and 116 in a hospice) were identified, resulting in 238 carers being eligible for interview or questionnaire survey. Overall, 106 successful interviews and 55 questionnaires were completed, giving a response rate of 67.6%. Carers gave a near unanimous vote of excellence for the total care given by the hospice, while around 40% of carers of patients in community hospitals considered that improvements were possible. Community hospitals attracted more negative comments than hospices, with criticism being directed at problems of communication, lack of nursing staff, and lack of support in bereavement. Carers of hospice patients were significantly more likely to be present at the time of death than those of community hospital patients [45/70 (64%) vs. 31/89 (35%); chi 2 = 13.6, P < 0.001], an observation possibly because nursing staff in community hospitals are less experienced at dealing with terminally ill patients and such hospitals have fewer adequate facilities. CONCLUSIONS: Lay carers indicated great satisfaction with care given in the hospice and less satisfaction with care given in the community hospitals. However, the community hospitals are non-specialist units with far lower levels of trained staff. Improvements in terms of the communication skills of doctors and nurses, specific training for nurses in palliative care, and structured bereavement care could be made without necessarily increasing staffing numbers.

Attitude to Health↗
PubMed1997

Cytotoxicity and antiestrogenicity of a novel series of basic diphenylethylenes.

On the premise that it is necessary to develop antiestrogens with a higher cytotoxic component in order to reduce the risks of the development of heterogeneous malignant cell populations in breast cancer, we studied a novel series of basic diphenylethylenes, for the most part devoid of estrogenic activity, with low antiestrogenicity but much enhanced cytotoxicity compared to the reference drug tamoxifen. The main structural features associated with cytotoxicity were E isomery, substituents of five to eight carbons on the ethylene bond, and dibasicity.

Antineoplastic Agents↗
PubMed1997

Ecotoxicity hazard assessment of styrene.

The ecotoxicity of styrene was evaluated in acute toxicity studies of fathead minnows (Pimephales promelas), daphnids (Daphnia magna), amphipods (Hyalella azteca), and freshwater green algae (Selenastrum capricornutum), and a subacute toxicity study of earthworms (Eisenia fostida). Stable exposure levels were maintained in the studies with fathead minnows, daphnids, and amphipods using sealed, flowthrough, serial dilution systems and test vessels. The algae were evaluated in a sealed, static system. The earthworms were exposed in artificial soil which was renewed after 7 days. Styrene concentrations in water and soil were analyzed by gas chromatography with flame ionization detection following extraction into hexane. Test results are based on measured concentrations. Styrene was moderately toxic to fathead minnows, daphnids, and amphipods: fathead minnow: LC50 (96 hr), 10 mg/liter, and NOEC, 4.0 mg/liter; daphnids: EC50 (48 hr), 4.7 mg/liter, and NOEC, 1.9 mg/liter; amphipods: LC50 (96 hr), 9.5 mg/liter, and NOEC, 4.1 mg/liter. Styrene was highly toxic to green algae: EC50 (96 hr), 0.72 mg/liter, and NOEC, 0.063 mg/liter; these effects were found to be algistatic rather than algicidal. Styrene was slightly toxic to earthworms: LC50 (14 days), 120 mg/kg, and NOEC, 44 mg/kg. There was no indication of a concern for chronic toxicity based on these studies. Styrene's potential impact on aquatic and soil environments is significantly mitigated by its volatility and biodegradability.

Animals↗
PubMed1997

In vitro targeting of antibody-conjugated echogenic liposomes for site-specific ultrasonic image enhancement.

Tissue-specific ultrasonic enhancement can be used for the detection and characterization of atherosclerosis. We have previously demonstrated the generation of inherently echogenic (acoustically reflective) liposomes solely by varying lipid composition and controlling the method of production. In this study, echogenic liposomes composed of phosphatidylcholine (PC), 4-(p-maleimidophenyl) butyryl phosphatidylethanolamine (MPB-PE), phosphatidylglycerol (PG), and cholesterol were conjugated to human gamma globulin to determine the effect of antibody conjugation on liposomal acoustic reflectivity. The liposomes remained highly echogenic following antibody conjugation. Echogenic liposomes were also conjugated to rabbit antihuman fibrinogen to study their ability to target fibrin. Antibody-conjugated liposomes were targeted to fibrin-coated filter paper and slides, thrombi made in vitro, and segments of atheroma in an animal model of atherosclerosis. Liposomes were detected by scanning electron microscopy, radiolabeling, and imaging with intravascular ultrasound. Electron microscopy revealed attachment of antibody-conjugated liposomes to fibrin on slides and to the fibrous plaques of the arterial segments, whereas unconjugated liposomes did not attach. Similarly, conjugated liposomes did not attach to normal arteries, indicating their binding to the arterial segment is directed towards a component of the fibrous plaque. Ultrasound imaging of the thrombi demonstrated surface attachment of the acoustic conjugated liposomes. 125I-Labeled liposomes conjugated to rabbit anti-human were targeted to fibrin-coated paper. Counting specifically bound radioactivity showed that > 84% of applied liposomes remained attached to the fibrin after washing with saline. These results demonstrate the potential of acoustically reflective liposomes for site-specific targeting and acoustic enhancement.

Animals↗
PubMed1997

Low specificity of PGP9.5 expression for detection of micrometastatic neuroblastoma.

To determine the specificity of neuroendocrine protein gene product (PGP9.5) gene transcripts for detecting micrometastatic neuroblastoma, we have used a highly sensitive polymerase chain reaction (PCR) technique to evaluate expression of this gene in normal blood and bone marrow. While expression of the tyrosine hydroxylase gene was not detected in any normal sample, low-level PGP9.5 expression was detected in eight out of ten blood and seven of 12 marrow samples. PGP9.5 gene transcripts in normal tissues have the potential to interfere with the detection of micrometastatic neuroblastoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Migration studies from paper and board food packaging materials. 1. Compositional analysis.

A survey of 32 paper and board materials intended for food contact has been undertaken. Sample composition was analysed to identify chemicals with a potential to migrate to foods. Representative materials covering a range of uses such as aqueous and fatty foods, and use at ambient and elevated temperatures, were obtained from industry. The samples were examined in their unfinished state, even where the final form would have included lamination to plastics, printing, or other treatments. A comprehensive and systematic analytical approach was applied which included determination of volatiles by headspace GC-MS, extraction using water, ethanol and chloroform with subsequent analysis by GC-MS and HPLC, and multi-element screening by ICP-MS. The solvent extracts were also weighed to determine the total amount of material available for migration. A large number of volatile substances were identified with alkyl and aryl aldehydes predominating in the majority of samples. Substances identified in solvent extracts included 2,6-di-tert-butyl-4-hydroxytoluene (BHT), di-tert-butylphenol, benzophenone, 4,4'-bis(dimethyl amino) benzophenone (Michler's ketone), triphenyl methane, bicyclohexylphenylphenanthrene carboxylic acid (and its methyl ester) and abietic acid. Levels of these substances were however generally below 1 mg/kg paper. Of the inorganic elements, arsenic and mercury were not detected above the limits of determination of 1.8 and 0.4 mg/kg respectively in any of the 10 samples examined. Cadmium was detected in teabag tissue and in unbleached Kraft paper at 0.3 mg/kg. Chromium was present in seven samples at 1.1-7.8 mg/kg, whilst lead was present in nine of the 10 samples at levels ranging from 0.3 to 5.9 mg/kg.

Benzophenones↗
PubMed1997

Migration studies from paper and board food packaging materials. Part 2. Survey for residues of dialkylamino benzophenone UV-cure ink photoinitiators.

A survey of retail samples was conducted in two phases with 50 general paper and board food contact materials and articles analysed in 1992, and 121 samples, specifically of printed cartonboard, analysed in 1995. Packaging samples were extracted with ethanol containing 0.4% triethylamine. The extracts were analysed using high performance liquid chromatography (HPLC) and the presence of 4,4'-bis (dimethylamino) benzophenone (Michler's ketone, MK) and 4,4'-bis (diethylamino)-benzophenone (DEAB) confirmed using gas chromatography coupled to mass spectroscopy (GC-MS). The limits of detection for MK and DEAB in packaging were 0.05 mg/kg and 0.1-0.2 mg/kg respectively. In the first phase, MK was detected in 24% of the 50 samples at concentrations of 0.06-3.9 mg/kg paper. DEAB was detected in 12% of samples (0.1-0.2 mg/kg). In the second phase, 26% of the 121 cartonboard samples contained detectable MK (0.1-1.6 mg/kg) and 4% contained DEAB (0.2-0.7 mg/kg). Residues of the monoamine 4-(dimethylamino)benzophenone (DMAB) were found in 10% of the 1992 samples (0.1-0.6 mg/ kg). DMAB was not surveyed in 1995. These levels are too low to indicate the use of these cure agents for printing the packages. Rather, the most likely origin is from the use of recycled fibres. For three samples where the highest concentration of MK was detected, the food was analysed by GC-MS after extraction and clean-up. There was no measurable migration of MK at a detection limit of 2 micrograms/kg food. It is concluded, therefore, that the concentrations of MK present in the packaging samples analysed are unlikely to pose a risk to human health.

Benzophenones↗