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Biomedical subjects

J Hay

Publications and source records attributed to J Hay.

At least 19 recordsLinked to original sources
PubMed2002

Prophylaxis of radiation-associated mucositis in conventionally treated patients with head and neck cancer: a double-blind, phase III, randomized, controlled trial evaluating the clinical efficacy of an antimicrobial lozenge using a validated mucositis scoring system.

PURPOSE: Mucositis occurs in almost all patients treated with radiotherapy for head and neck cancer. The aim of this multicenter, double-blind, prospective, randomized trial was to evaluate the clinical efficacy of an economically viable antimicrobial lozenge (bacitracin, clotrimazole, and gentamicin [BcoG]) in the alleviation of radiation-induced mucositis in patients with head and neck cancer. PATIENTS AND METHODS: One hundred thirty-seven eligible patients were randomized to treatment with either antimicrobial lozenge (69 patients) or placebo lozenge (68 patients). The primary end point of the study was the time to development of severe mucositis from the start of radiotherapy. Secondary end points included severity and duration of mucositis, pain measurement, radiation therapy interruption, and quality of life. Mucositis was scored using a validated mucositis scoring system. RESULTS: Toxicity profiles were similar between the two arms of the study. The median time to development of severe mucositis from the start of radiotherapy was 3.61 weeks on BCoG and 3.96 weeks on placebo (P =.61). There were no statistically significant differences between the arms in the extent of severe mucositis as measured by physician, in oral toxicities as recorded by patients, or in radiotherapy delays. CONCLUSION: This study was conducted on the basis of a pilot study that demonstrated the BCoG lozenge to be tolerable and microbiologically efficacious. A validated mucositis scoring system was used. However, in this group of patients treated with conventional radiotherapy, the lozenge did not impact significantly on the severity of mucositis. Whether such a lozenge would be beneficial in treatment situations where rate of severe mucositis is higher (ie, in patients treated with unconventional fractionation or with concomitant chemotherapy) is unknown.

Administration, Oral↗
PubMed2002

Firing modes of midbrain dopamine cells in the freely moving rat.

There is a large body of data on the firing properties of dopamine cells in anaesthetised rats or rat brain slices. However, the extent to which these data relate to more natural conditions is uncertain, as there is little quantitative information available on the firing properties of these cells in freely moving rats. We examined this by recording from the midbrain dopamine cell fields using chronically implanted microwire electrodes. (1) In most cases, slowly firing cells with broad action potentials were profoundly inhibited by the dopamine agonist apomorphine, consistent with previously accepted criteria. However, a small group of cells was found that were difficult to classify because of ambiguous combinations of properties. (2) Presumed dopamine cells could be divided into low and high bursting (>40% of their spikes in bursts) groups, with the majority having low bursting rates. The distribution of burst incidence was similar to that previously reported with chloral hydrate anaesthesia, but the average intraburst frequency was higher in the conscious animal at rest and was higher again in bursts triggered by salient stimuli. (3) There was no evidence for spike frequency adaptation within bursts on average, consistent with the hypothesis that afterhyperpolarisation currents may be disabled during behaviourally induced bursting. (4) Presumed dopamine cells responded to reward-related stimuli with increased bursting rates and significantly higher intraburst frequencies compared to bursts emitted outside task context, indicating that modulation of afferent activity might not only trigger bursting, but may also regulate burst intensity. (5) In addition to the irregular single spike and bursting modes we found that extremely regular (clock-like) firing, previously only described for dopamine cells in reduced preparations, can also be expressed in the freely moving animal. (6) Cross-correlation analysis of activity recorded from simultaneously recorded neurones revealed coordinated activity in a quarter of dopamine cell pairs consistent with at least "functional" connectivity. On the other hand, most dopamine cell pairs showed no correlation, leaving open the possibility of functional sub-groupings within the dopamine cell fields. Taken together, the data suggest that the basic firing modes described for dopamine cells in reduced or anaesthetised preparations do reflect natural patterns of activity for these neurones, but also that the details of this activity are dependent upon modulation of afferent inputs by behavioural stimuli.

Action Potentials↗
PubMed2002

Recollection memory deficits in patients with major depressive disorder predicted by past depressions but not current mood state or treatment status.

BACKGROUND: Neuropsychological studies have suggested that memory systems reliant on medial temporal lobe structures are impaired in patients with depression. There is less data regarding whether this impairment is specific to recollection memory systems, and whether clinical features predict impairment. This study sought to address these issues. METHOD: A computerized process-dissociation memory task was utilized to dissociate recollection and habit memory in 40 patients with past or current major depression and 40 age, sex and IQ matched non-psychiatric control subjects. The Cognitive Failures Questionnaire was used to assess patients' perceptions of day-to-day memory failures. RESULTS: Patients had impaired recollection memory (t = 4.7, P < 0.001), but no impairment in habit memory when compared to controls. Recollection memory performance was not predicted by indices of current mood state, but was predicted by self-assessments of impairment (beta = -0.33; P = 0.008) and past number of depressions (beta = -0.41; P = 0.001). There was no evidence that standard therapy with antidepressant medication either improved or worsened memory performance. CONCLUSIONS: The results confirm that patients with multiple past depressions have reduced function on recollection memory tasks, but not on habit memory performance. The memory deficits were independent of current mood state but related to past course of illness and significant enough that patients detected impairment in day-to-day memory function.

Adult↗
PubMed2002

Glucose uptake and insulin action in human adipose tissue--influence of BMI, anatomical depot and body fat distribution.

OBJECTIVE: To examine and compare in vitro basal and insulin-stimulated glucose uptake in human omental and subcutaneous adipose tissue derived from lean, overweight or obese individuals, and in those with central or peripheral obesity. DESIGN: In vitro study of basal and insulin-stimulated 2-deoxyglucose uptake in human omental and subcutaneous adipose tissue explants derived from patients undergoing elective abdominal surgery. SUBJECTS: Fourteen lean (average age 47 y, average body mass index (BMI) 22 kg/m(2)), 12 overweight (average age 51 y, average BMI 27 kg/m(2)), and 15 obese subjects (average age 45 y, average BMI 39 kg/m(2)). Ten peripherally obese (average age 43 y, average WHR 0.76) and 17 centrally obese (average age 50 y, average waist-to-hip ratio (WHR) 0.92). MEASUREMENTS: Fatness and fat distribution parameters (by anthropometry), basal and insulin stimulated [(3)H]-2-deoxyglucose uptake in omental and subcutaneous adipose tissue explants. RESULTS: In adipose tissue from lean subjects transport of 2-deoxyglucose over basal was stimulated approximately two-fold by insulin. In contrast, 2-deoxyglucose transport in adipose tissue of obese or overweight subjects was not responsive to insulin. Following incubation with 100-nM insulin for 35 min, insulin-stimulated 2-deoxyglucose transport was significantly lower in both omental and subcutaneous adipose tissue of obese and overweight compared to lean subjects. Basal 2-deoxyglucose uptake was also significantly reduced in omental and subcutaneous tissue in obese compared to lean subjects. Depot-specific differences in 2-deoxyglucose uptake were also seen. Overall 2-deoxyglucose uptake was greater in omental than subcutaneous adipose tissue but this was due to increased basal levels rather than increased insulin action. The reduction in insulin-stimulated 2-deoxyglucose uptake seen in overweight and obese subjects was relatively similar in both depots. However, insulin responsive 2-deoxyglucose transport was significantly lower in the omental adipose tissue of subjects with central obesity, as compared to that of subjects with peripheral obesity. No difference in insulin induced 2-deoxyglucose transport was observed in the subcutaneous adipose tissue explants of subjects with either central or peripheral obesity. CONCLUSION: In lean individuals insulin responsiveness of omental and subcutaneous adipose tissue was similar, but basal glucose uptake was significantly higher in omental adipose tissue. Adipose tissue obtained from overweight as well as obese individuals is insulin resistant. This insulin resistance occurs at a lower BMI than previously expected and is not adipose-depot specific. However, in obese subjects with a central distribution of adiposity insulin resistance occurs at the site of omental adipose tissue, in contrast to those with peripheral obesity.

Adipose Tissue↗
PubMed2002

Isolation of human single chain antibodies (scFv) against human TNF-alpha from human peripheral blood lymphocyte-SCID mice.

By developing an appropriate immunization protocol for SCID (hu-PBL-SCID) mice engrafted with human peripheral blood lymphocytes in combination with scFv phage display library, we were able to establish an efficient strategy to obtain human scFv clones against a human self-antigen, TNF-alpha. The mice pretreated with gamma-radiation (3Gy) and anti-asialo GM1 antibody were immunized with a mixture of human TNF-alpha-keyhole limpet hemocyanin and Freund's adjuvant. Human antibody maturation was suggested to be induced in the mice with the immunization protocol. The scFv clones obtained from the mice were shown to exhibit binding affinities in the range of 10(7)-10(8) M(-1). Together with our previously published work on the isolation of respiratory syncytial virus neutralizing scFvs, the results of this study have implicated that this combined approach is one of the effective alternatives for the cloning of human monoclonal antibodies specific for a wide range of antigens of interest.

Amino Acid Sequence↗
PubMed2001

Cis and trans elements regulating expression of the varicella zoster virus gI gene.

We have identified cis- and trans-acting elements involved in the VZV IE62 protein-activated expression of the varicella zoster virus (VZV) gene which encodes the viral gI glycoprotein. The cis-acting elements include a non-canonical TATA box and a novel 19 base pair sequence located just upstream of the TATA element designated the "activating upstream sequence" or AUS. The AUS is a movable element and its presence results in IE62 activation of a chimeric promoter consisting of the VZV gC TATA box and the gI AUS. We have also determined that the VZV ORF 29 protein modulates the regulatory activity of the IE62 protein at the gI promoter. In combination with the IE62 transactivator, it yields a 10 to 15-fold increase in expression over the levels seen with the IE62 protein alone in T lymphocytes. The upmodulatory activity requires the presence of a 40 base pair sequence, designated the 29RE, which maps between positions -220 and -180 in the gI promoter. In this paper we review these and earlier findings from our laboratories concerning the regulation of the gI promoter.

Cell Line↗
PubMed2001

Interactions among structural proteins of varicella zoster virus.

Varicella zoster virus tegument components include the regulatory proteins IE4, IE62, IE63 and the ORFI0 protein, a protein kinase (ORF47) and an abundant protein encoded in ORF9 which is the homolog of HSV VP22. The kinase is able to phosphorylate IE62 and the ORF9 protein specifically in viral particles. We show that interactions among these proteins are, at least in part, dependent on the presence or absence of phosphate groups and we suggest models for tegument formation and for its dissolution in the infected cell.

Animals↗
PubMed2001

An exploration of evolved mental mechanisms for dominant and subordinate behaviour in relation to auditory hallucinations in schizophrenia and critical thoughts in depression.

BACKGROUND: Mental mechanisms have evolved to enable animals (and humans) to be able to function in various social roles. It is suggested that the nature and functions of the mental mechanisms that enable animals to act as a hostile-dominant or threatened-subordinate can be distinguished. It is further suggested these can be internally activated and 'play off' against each other, such that a person 'attacks' themselves and then responds to their own internal attacks with subordinate defences. Hence, a depressed person can submit, feel defeated, belittled, beaten down, or want to run away (escape) from their own self-attacking thoughts, while psychotic voice hearers can feel similarly to their hostile voices. Such internal interactions may relate to depression in both psychotic voice hearers and depressed people. METHOD: A group of 66 voice hearers with a diagnosis of schizophrenia and 50 depressed patients were compared on a series of self-report questionnaires measuring the power of hostile self-directed thoughts/voices and the activation of defensive responses, especially fight/flight. RESULTS: We present evidence that schizophrenic, malevolent voice hearers and self-critical depressed people experience their hostile, internally generated voices/thoughts as powerful, dominating and controlling (i.e. have typical characteristics of a hostile dominant). Moreover, these voices/thoughts activate evolved subordinate defences such as fight/flight and these are associated with depression in both depression and schizophrenia. CONCLUSION: Conceptualizing aspects of depressed and psychotic thinking as relating to evolved mental mechanisms, which are role serving, but can internally play off against each other, may open new ways of investigating certain aspects of severe pathologies.

Adult↗
PubMed2001

Embedding health-promoting changes into the daily lives of independent-living older adults: long-term follow-up of occupational therapy intervention.

The Well Elderly Study was a randomized trial in independent-living older adults that found significant health, function, and quality of life benefits attributable to a 9-month program in preventive occupational therapy (OT). All participants completing the trial were followed for an additional 6 months without further intervention and then reevaluated using the same battery of instruments. Long-term benefit attributable to preventive OT was found for the quality of interaction scale of the Functional Status Questionnaire and for six of eight scales on the RAND SF-36: physical functioning, role functioning, vitality, social functioning, role emotional, and general mental health (p<.05). Approximately 90% of the therapeutic gain observed following OT treatment was retained in follow-up. The finding of a sustained effect for preventive OT is of great public health relevance given the looming health care cost crisis associated with our nation's expanding elderly population.

Activities of Daily Living↗
PubMed2001

Use of subgenic 18S ribosomal DNA PCR and sequencing for genus and genotype identification of acanthamoebae from humans with keratitis and from sewage sludge.

This study identified subgenic PCR amplimers from 18S rDNA that were (i) highly specific for the genus Acanthamoeba, (ii) obtainable from all known genotypes, and (iii) useful for identification of individual genotypes. A 423- to 551-bp Acanthamoeba-specific amplimer ASA.S1 obtained with primers JDP1 and JDP2 was the most reliable for purposes i and ii. A variable region within this amplimer also identified genotype clusters, but purpose iii was best achieved with sequencing of the genotype-specific amplimer GTSA.B1. Because this amplimer could be obtained from any eukaryote, axenic Acanthamoeba cultures were required for its study. GTSA.B1, produced with primers CRN5 and 1137, extended between reference bp 1 and 1475. Genotypic identification relied on three segments: bp 178 to 355, 705 to 926, and 1175 to 1379. ASA.S1 was obtained from single amoeba, from cultures of all known 18S rDNA genotypes, and from corneal scrapings of Scottish patients with suspected Acanthamoeba keratitis (AK). The AK PCR findings were consistent with culture results for 11 of 15 culture-positive specimens and detected Acanthamoeba in one of nine culture-negative specimens. ASA.S1 sequences were examined for 6 of the 11 culture-positive isolates and were most closely associated with genotypic cluster T3-T4-T11. A similar distance analysis using GTSA.B1 sequences identified nine South African AK-associated isolates as genotype T4 and three isolates from sewage sludge as genotype T5. Our results demonstrate the usefulness of 18S ribosomal DNA PCR amplimers ASA.S1 and GTSA.B1 for Acanthamoeba-specific detection and reliable genotyping, respectively, and provide further evidence that T4 is the predominant genotype in AK.

Acanthamoeba↗
PubMed2001

Mutational analysis of the repeated open reading frames, ORFs 63 and 70 and ORFs 64 and 69, of varicella-zoster virus.

Varicella-zoster virus (VZV) open reading frame 63 (ORF63), located between nucleotides 110581 and 111417 in the internal repeat region, encodes a nuclear phosphoprotein which is homologous to herpes simplex virus type 1 (HSV-1) ICP22 and is duplicated in the terminal repeat region as ORF70 (nucleotides 118480 to 119316). We evaluated the role of ORFs 63 and 70 in VZV replication, using recombinant VZV cosmids and PCR-based mutagenesis to make single and dual deletions of these ORFs. VZV was recovered within 8 to 10 days when cosmids with single deletions were transfected into melanoma cells along with the three intact VZV cosmids. In contrast, VZV was not detected in transfections carried out with a dual deletion cosmid. Infectious virus was recovered when ORF63 was cloned into a nonnative AvrII site in this cosmid, confirming that failure to generate virus was due to the dual ORF63/70 deletion and that replication required at least one gene copy. This requirement may be related to our observation that ORF63 interacts directly with ORF62, the major immediate-early transactivating protein of VZV. ORF64 is located within the inverted repeat region between nucleotides 111565 and 112107; it has some homology to the HSV-1 Us10 gene and is duplicated as ORF69 (nucleotides 117790 to 118332). ORF64 and ORF69 were deleted individually or simultaneously using the VZV cosmid system. Single deletions of ORF64 or ORF69 yielded viral plaques with the same kinetics and morphology as viruses generated with the parental cosmids. The dual deletion of ORF64 and ORF69 was associated with an abnormal plaque phenotype characterized by very large, multinucleated syncytia. Finally, all of the deletion mutants that yielded recombinants retained infectivity for human T cells in vitro and replicated efficiently in human skin in the SCIDhu mouse model of VZV pathogenesis.

Animals↗
PubMed2001

Varicella-zoster virus ORF47 protein serine kinase: characterization of a cloned, biologically active phosphotransferase and two viral substrates, ORF62 and ORF63.

Varicella-zoster virus (VZV) codes for a protein serine kinase called ORF47; the herpes simplex virus (HSV) homolog is UL13. No recombinant alphaherpesvirus serine kinase has been biologically active in vitro. We discovered that preservation of the intrinsic kinase activity of recombinant VZV ORF47 required unusually stringent in vitro conditions, including physiological concentrations of polyamines. In this assay, ORF47 phosphorylated two VZV regulatory proteins: the ORF62 protein (homolog of HSV ICP4) and the ORF63 protein (homolog of HSV ICP22). Of interest, ORF47 kinase also coprecipitated ORF63 protein from the kinase assay supernatant.

Aspartic Acid↗
PubMed2001

The response of molecular isoforms of growth hormone to acute exercise in trained adult males.

Circulating GH consists of multiple molecular isoforms, all derived from the one gene in nonpregnant humans. To assess the effect of a potent stimulus to pituitary secretion on GH isoforms, we studied 17 aerobically trained males (age, 26.9 +/- 1.5 yr) in a randomized, repeat measures study of rest vs. exercise. Exercise consisted of continuous cycle ergometry at approximately 80% of predetermined maximal oxygen uptake for 20 min. Serum was assayed for total, pituitary, 22-kDa, recombinant, non-22-kDa, 20-kDa, and immunofunctional GH. All isoforms increased during, peaked at the end, and declined after exercise. At peak exercise, 22-kDa GH was the predominant isoform. After exercise, the ratios of non-22 kDa/total GH and 20-kDa GH/total GH increased and those of recombinant/pituitary GH decreased. The disappearance half-times for pituitary GH and 20-kDa GH were significantly longer than those for all other isoforms. We conclude that 1) all molecular isoforms of GH measured increased with and peaked at the end of acute exercise, with 22-kDa GH constituting the major isoform in serum during exercise; and 2) the proportion of non-22-kDa isoforms increased after exercise due in part to slower disappearance rates of 20-kDa and perhaps other non-22-kDa GH isoforms. It remains to be determined whether the various biological actions of different GH isoforms impact on postexercise homeostasis.

Adult↗
PubMed2001

Changes in non-22-kilodalton (kDa) isoforms of growth hormone (GH) after administration of 22-kDa recombinant human GH in trained adult males.

GH is being used by elite athletes to enhance sporting performance. To examine the hypothesis that exogenous 22-kDa recombinant human GH (rhGH) administration could be detected through suppression of non-22-kDa isoforms of GH, we studied seventeen aerobically trained males (age, 26.9 +/- 1.5 yr) randomized to rhGH or placebo treatment (0.15 IU/kg/day for 1 week). Subjects were studied at rest and in response to exercise (cycle-ergometry at 65% of maximal work capacity for 20 min). Serum was assayed for total GH (Pharmacia IRMA and pituitary GH), 22-kDa GH (2 different 2-site monoclonal immunoassays), non-22-kDa GH (22-kDa GH-exclusion assay), 20-kDa GH, and immunofunctional GH. In the study, 3 h after the last dose of rhGH, total and 22-kDa GH concentrations were elevated, reflecting exogenous 22-kDa GH. Non-22-kDa and 20-kDa GH levels were suppressed. Regression of non-22-kDa or 20-kDa GH against total or 22-kDa GH produced clear separation of treatment groups. In identical exercise studies repeated between 24 and 96 h after cessation of treatment, the magnitude of the responses of all GH isoforms was suppressed (P < 0.01), but the relative proportions were similar to those before treatment. We conclude: 1) supraphysiological doses of rhGH in trained adult males suppressed exercise-stimulated endogenous circulating isoforms of GH for up to 4 days; 2) the clearest separation of treatment groups required the simultaneous presence of high exogenous 22-kDa GH and suppressed 20-kDa or non-22-kDa GH concentrations; and 3) these methods may prove useful in detecting rhGH abuse in athletes.

Adult↗
PubMed2001

Use of radiotherapy for control of sialorrhea in patients with amyotrophic lateral sclerosis.

Many patients with amyotrophic lateral sclerosis (ALS) develop progressive difficulty with swallowing secretions, and drooling becomes a significant problem. The production of saliva can be reduced with radiation of the submandibular and sublingual salivary gland tissue. This method has been used successfully in Europe and had limited use at Vancouver Hospital. This study was undertaken to determine the lowest effective dose of radiation necessary to control salivary production. Over a 3-year period, patients with ALS who developed significant problems with drooling were identified and treated with a predetermined dose of radiation. The first group received a single dose of 8 Gy in one fraction and the second received a total of 12.5 Gy in two fractions. They were followed over the next 6 months and were evaluated for effectiveness and side effects. Their saliva was measured pre- and postradiation treatment, and they were also asked to evaluate the change subjectively, using a questionnaire. The preliminary findings suggest that 8 Gy of radiation was effective in controlling drooling, and increasing the dose did not improve initial control. Long-term control was difficult to evaluate as the patients entered in the study were very ill and their life expectancy was very short. Radiation at this low dose resulted in very few side effects. Low-dose radiation can safely help control secretions in selected patients with ALS.

Amyotrophic Lateral Sclerosis↗
PubMed2000

Varicella-zoster virus gE escape mutant VZV-MSP exhibits an accelerated cell-to-cell spread phenotype in both infected cell cultures and SCID-hu mice.

Varicella-zoster virus is considered to have one of the most stable genomes of all human herpesviruses. In 1998, we reported the unanticipated discovery of a wild-type virus that had lost an immunodominant B-cell epitope on the gE ectodomain (VZV-MSP); the gE escape mutant virus exhibited an unusual pattern of egress. Further studies have now documented a markedly enhanced cell-to-cell spread by the mutant virus in cell culture. This property was investigated by laser scanning confocal microscopy combined with a software program that allows the measurement of pixel intensity of the fluorescent signal. For this new application of imaging technology, the VZV immediate early protein 62 (IE 62) was selected as the fluoresceinated marker. By 48 h postinfection, the number of IE 62-positive pixels in the VZV-MSP-infected culture was nearly fourfold greater than the number of pixels in a culture infected with a low-passage laboratory strain. Titrations by infectious center assays supported the above image analysis data. Confirmatory studies in the SCID-hu mouse documented that VZV-MSP spread more rapidly than other VZV strains in human fetal skin implants. Generally, the cytopathology and vesicle formation produced by other strains at 21 days postinfection were demonstrable with VZV-MSP at 14 days. To assess whether additional genes were contributing to the unusual VZV-MSP phenotype, approximately 20 kb of the VZV-MSP genome was sequenced, including ORFs 31 (gB), 37 (gH), 47, 60 (gL), 61, 62 (IE 62), 66, 67 (gI), and 68 (gE). Except for a few polymorphisms, as well as the previously discovered mutation within gE, the nucleotide sequences within most open reading frames were identical to the prototype VZV-Dumas strain. In short, VZV-MSP represents a novel variant virus with a distinguishable phenotype demonstrable in both infected cell cultures and SCID-hu mice.

Animals↗
PubMed2000

Physical interaction between two varicella zoster virus gene regulatory proteins, IE4 and IE62.

Transfection assays demonstrate that the varicella zoster virus (VZV) immediate-early 62 (IE62) protein is a major transactivator of VZV gene expression, whereas a second immediate-early protein, IE4, can act as a major coactivator of transactivation mediated through IE62. To test whether IE62 and IE4 interact physically, we performed several protein-protein interaction assays. Coimmunoprecipitation analyses using VZV-infected cell lysates as well as purified protein mixtures demonstrate that IE62 and IE4 form stable complexes in solution under stringent salt conditions. Enzyme-linked immunosorbent assay protein-protein interaction assays and maltose-binding protein capture assays demonstrate that IE62 binds IE4 in a concentration- and dose-dependent manner. Far Western blot analyses show that IE4 binds to an undermodified form of IE62, and the use of calf intestinal phosphatase and protein kinases suggests that the interaction with IE4 is dependent on the phosphorylation state of IE62. An IE4 binding domain on IE62 has been mapped using a set of truncated IE62 fusion peptides. Collectively, these results imply a direct and specific physical interaction between IE4 and less-phosphorylated forms of IE62. These data have implications for virion assembly, as well as for the regulation of gene expression in VZV-infected cells.

Amino Acid Sequence↗