Biomedical subjects

J G Turner

Publications and source records attributed to J G Turner.

At least 37 records · Page 2Linked to original sources

PubMed1999

Prolonged exposure to an augmented acoustic environment ameliorates age-related auditory changes in C57BL/6J and DBA/2J mice.

The effects of exposure to an augmented acoustic environment (AAE) on auditory function were evaluated in mouse strains that exhibit high-frequency hearing loss beginning during young adulthood (the C57BL/6J strain [C57]) or around the time of weaning/ adolescence (the DBA/2J strain [DBA]). Beginning at age 25 days, mice were exposed 12 h every night to a 70 dB SPL broad-band noise AAE. The AAE was maintained until age 14 months in C57 mice and 9 months in DBA mice. Control mice were age-matched and maintained under normal vivarium acoustic conditions. The auditory brainstem response (ABR), acoustic startle response amplitude, and prepulse inhibition (PPI) were used to assess the auditory system. Exposure to the AAE resulted in improved auditory performance in both strains (better PPI, lower ABR thresholds, bigger startle amplitudes).

Acoustic Stimulation↗

PubMed1999

Validation of the Sign and Symptom Check-List for Persons with HIV Disease (SSC-HIV).

Symptom management for persons living with HIV disease is recognized as an extremely important component of care management. This article reports the validation of a new sign and symptom assessment tool designed to assess the intensity of HIV-related symptoms using two samples (study 1: n=247; study 2: n=686) of people living with HIV disease. Study 1 data were collected between 1994 and 1996 before the initiation of highly active antiretroviral therapy (HAART). Study 2 data were collected between 1997 and 1998 after the wide adoption of HAART therapy. The initial version of the Sign and Symptom Check-List for Persons with HIV Disease (SSC-HIV) included 41 signs and symptoms. This scale was submitted to a principal components factor analysis with a varimax rotation. The final solution reports six factors explaining 68.9% of the variance. The six symptom clusters (factors), the number of items in the factor, and the Cronbach alpha reliability estimates were: malaise/weakness/fatigue (six items, alpha=0.90); confusion/distress (four items, alpha=0.90); fever/chills (four items, alpha=0.85); gastrointestinal discomfort (four items, alpha=0. 81); shortness of breath (three items, alpha=0.79); and nausea/vomiting (three items, alpha=0.77). These six factors have strong reliability estimates and a stable factor structure that supports the construct validity of the 26-item instrument. Additional evidence supports the concurrent validity of the scale as well as its sensitivity to change over time. The final version of the SSC-HIV is a 26-item scale available for use by clinicians and researchers to measure the patient's self-report of HIV-related signs and symptoms.

Adult↗

PubMed1999

Predictors of self-reported adherence in persons living with HIV disease.

This study examined the relationships between the five dimensions of the Wilson and Cleary model of health-related quality of life and three self-reported adherence measures in persons living with HIV using a descriptive survey design. Data collection occurred in seven cities across the United States, including university-based AIDS clinics, private practices, public and for-profit hospitals, residential and day-care facilities, community-based organizations, and home care. The three dependent adherence measures studied were "medication nonadherence," "follows provider advice," and "missed appointments." The sample included 420 persons living with HIV disease with a mean age of 39 years of which 20% were women and 51% were white; subjects had a mean CD4 count of 321 mm3. HIV-positive clients with higher symptom scores, particularly depression, were more likely to be nonadherent to medication, not to follow provider advice, and to miss appointments. Participants who reported having a meaningful life, feeling comfortable and well cared for, using their time wisely, and taking time for important things were both more adherent to their medications and more likely to follow provider's advice. No evidence was found demonstrating any relationship between adherence and age, gender, ethnicity, or history of injection drug use. These findings support the need to treat symptoms, particularly depression, and to understand clients' perceptions of their environment as strategies to enhance adherence. A limitation of this study was that adherence was measured only by self-report; however, the study did expand the concept of adherence in HIV care beyond medication adherence to include following instructions and keeping appointments.

Adult↗

PubMed1999

Comparison of Erysiphe cichoracearum and E. cruciferarum and a survey of 360 Arabidopsis thaliana accessions for resistance to these two powdery mildew pathogens.

In previous work, UEA1 and UCSC1, two geographically distinct, powdery mildew isolates, were recognized for their ability to infect Arabidopsis thaliana. We have clarified the identity of these isolates by determining their host ranges, reexamining their morphology, and comparing their DNA sequences for the 5.8S ribosomal RNA and two flanking internal transcribed spacer sequences. These experiments confirm that UEA1 is a member of Erysiphe cruciferarum and that UCSC1 belongs to E. cichoracearum. Interactions of the two Erysiphe isolates with 360 A. thaliana accessions were examined to provide a comprehensive profile of naturally occurring powdery mildew resistance in this weedy species. The majority of A. thaliana accessions (213) were susceptible to both isolates. Among the accessions exhibiting some degree of resistance, most (84) responded differentially to UEA1 and UCSC1 and the remainder were resistant to both isolates. Notably, resistance to UCSC1 cosegregated with RPW7, a locus previously demonstrated to confer resistance to UEA1 in Ms-0 x Landsberg (erecta) crosses. With this large collection of resistant accessions, questions about species specificity, genetic diversity and the evolution of resistance to powdery mildews can be addressed.

Arabidopsis↗

PubMed1999

Neuroendocrine prediction of left ventricular function and heart failure after acute myocardial infarction. The Christchurch Cardioendocrine Research Group.

OBJECTIVE: To determine the relations of plasma levels of brain natriuretic peptide (BNP), atrial natriuretic factor (ANF), N-terminal ANF (N-ANF), cyclic guanosine monophosphate (cGMP; the cardiac peptide second messenger), and plasma catecholamines to left ventricular function and to prognosis in patients admitted with acute myocardial infarction. DESIGN: Plasma hormones and ventricular function (radionuclide ventriculography) were measured 1-4 days after myocardial infarction in 220 patients admitted to a single coronary care unit. Radionuclide scanning was repeated 3-5 months after infarction. Clinical events were recorded over a mean period of 14 months. RESULTS: Both early and late left ventricular ejection fraction (LVEF) were most closely related to plasma BNP (r = -0.60, n = 220, p < 0.001; and r = -0.53, n = 192, p < 0.001, respectively), followed by ANF, N-ANF, cGMP, and the plasma catecholamines. Early plasma BNP concentrations less than twofold the upper limit of normal (20 pmol/l) had 100% negative predictive value for LVEF < 40% at 3-5 months after infarction. In multivariate analysis incorporating all the neurohormonal factors, only BNP remained independently predictive of LVEF < 40% (p < 0.005). Survival analysis by median levels of candidate predictors identified BNP as the most powerful discriminator for death (p < 0.0001). No early deaths (within 4 months) occurred in patients with plasma BNP concentrations below the group median (27 pmol/l), and over follow up only three of 26 deaths occurred in this subgroup. Of all episodes of left ventricular failure, 85% occurred in patients with plasma BNP above the median (p < 0.001). In multivariate analyses, BNP alone gave additional predictive information beyond sex, age, clinical history, LVEF, and plasma noradrenaline for both subsequent onset of LVF and death. CONCLUSIONS: Plasma BNP measured within 1-4 days of acute myocardial infarction is a powerful independent predictor of left ventricular function, heart failure, or death over the subsequent 14 months, and superior to ANF, N-ANF, cGMP, and plasma catecholamines.

Atrial Natriuretic Factor↗

PubMed1998

Broadened clinical utility of gene gun-mediated, granulocyte-macrophage colony-stimulating factor cDNA-based tumor cell vaccines as demonstrated with a mouse myeloma model.

Effective immunization against the murine B16 melanoma by a nonviral approach in which a gene gun is used to transfer GM-CSF cDNA into tumor cells has been described. We have extended this nonviral approach by using the poorly immunogenic murine myeloma MPC11 model. Vaccination with the transfected, GM-CSF-expressing MPC11 cells induced a potent antitumor cytotoxic T lymphocyte response associated with tumor rejection in the majority of the test mice. Furthermore, nearly 100% (27 of 28) of the tumor-free mice were able to reject a tumor rechallenge. While this approach is clinically attractive because of minimal tissue manipulation/culturing and the absence of infectious agents, a number of tested human primary tumors, including myeloma cells, have failed to produce high levels of GM-CSF after gene gun transfection. To circumvent the low transfection efficiency in certain human tumor cells, we showed that combining irradiated tumor cells to provide tumor antigens together with gene gun-transfected fibroblasts to provide GM-CSF induced effective tumor rejection. We also report that normal human skin fibroblasts transfected by the gene gun produce high levels of human GM-CSF (250 ng/10(6) cells/24 hr). These results suggest that combining irradiated tumor cells with gene gun-transfected fibroblasts results in antitumor immune responses and may allow for a wider application of this approach to cancer immunotherapy.

3T3 Cells↗

PubMed1998

Plasma N-terminal pro-brain natriuretic peptide and adrenomedullin: new neurohormonal predictors of left ventricular function and prognosis after myocardial infarction.

BACKGROUND: Newly discovered circulating peptides, N-terminal pro-brain natriuretic peptide (N-BNP) and adrenomedullin (ADM), were examined for prediction of cardiac function and prognosis and compared with previously reported markers in 121 patients with myocardial infarction. METHODS AND RESULTS: The association between radionuclide left ventricular ejection fraction (LVEF) and N-BNP at 2 to 4 days (r=-.63, P<.0001) and 3 to 5 months (r=-.58, P<.0001) after infarction was comparable to that for C-terminal BNP and far stronger than for ADM (r=-.26, P<.01), N-terminal atrial natriuretic peptide (N-ANP), C-terminal ANP, cGMP, or plasma catecholamine concentrations. For prediction of death over 24 months of follow-up, an early postinfarction N-BNP level > or = 160 pmol/L had sensitivity, specificity, positive predictive value, and negative predictive values of 91%, 72%, 39%, and 97%, respectively, and was superior to any other neurohormone measured and to LVEF. Only 1 of 21 deaths occurred in a patient with an N-BNP level below the group median (Kaplan-Meier survival analysis, P<.00001). For prediction of heart failure (left ventricular failure), plasma N-BNP > or = 145 pmol/L had sensitivity (85%) and negative predictive value (91%) comparable to the other cardiac peptides and was superior to ADM, plasma catecholamines, and LVEF. By multivariate analysis, N-BNP but not ADM provided predictive information for death and left ventricular failure independent of patient age, sex, LVEF, levels of other hormones, and previous history of heart failure, myocardial infarction, hypertension, or diabetes. CONCLUSIONS: Plasma N-BNP measured 2 to 4 days after myocardial infarction independently predicted left ventricular function and 2-year survival. Stratification of patients into low- and high-risk groups can be facilitated by plasma N-BNP or BNP measurements, and one of these could reasonably be included in the routine clinical workup of patients after myocardial infarction.

Adrenomedullin↗

PubMed1998

COI1: an Arabidopsis gene required for jasmonate-regulated defense and fertility.

The coi1 mutation defines an Arabidopsis gene required for response to jasmonates, which regulate defense against insects and pathogens, wound healing, and pollen fertility. The wild-type allele, COI1, was mapped to a 90-kilobase genomic fragment and located by complementation of coi1-1 mutants. The predicted amino acid sequence of the COI1 protein contains 16 leucine-rich repeats and an F-box motif. It has similarity to the F-box proteins Arabidopsis TIR1, human Skp2, and yeast Grr1, which appear to function by targeting repressor proteins for removal by ubiquitination.

Acetates↗

PubMed1998

A population-based study of bone mineral density in women with longstanding type 1 (insulin dependent) diabetes.

This study aimed to explore multiple determinants of BMD (bone mineral density) in 99 women with long-standing type 1 diabetes, recruited from a population based register of insulin users. BMD was measured using DEXA (dual energy X-ray absorptiometry) at the femoral neck and lumbar spine, age adjusted Z scores were calculated and results compared to those of healthy volunteers. The median age of diabetic subjects was 42 years and the median duration of diabetes was 27 years. BMD was positively associated with body mass index and height at both the lumbar spine and femoral neck. There was a positive association with oral contraceptive pill use and lumbar spine BMD, and peripheral vascular disease was negatively associated with femoral neck BMD. No correlation was seen with either age or duration of diabetes and absolute BMD values. Mean Z score at the femoral neck was -0.12 (95% confidence interval -0.37 to +0.12). At the lumbar spine, the corresponding value was -0.21 (-0.44 to +0.02). Pre- and post-menopausal values for the diabetic subjects and healthy volunteers were found to be similar. In summary, axial BMD values in subjects with long-standing diabetes were similar to those observed in healthy non diabetic populations.

Adult↗

PubMed1998

Prolonged stress-induced elevation in plasma corticosterone during pregnancy in the rat: implications for prenatal stress studies.

Experiments were conducted to test the hypothesis that exposure to uncontrollable stress during pregnancy results in a heightened elevation of plasma glucocorticoids. Rats were exposed to uncontrollable electric tail shocks every other day during the 3 weeks of pregnancy. Plasma corticosterone concentrations in stressed dams increased significantly from gestation days 4 to 20. Importantly, this increase in plasma corticosterone occurred 24- and 48-h after exposure to stress suggesting a prolonged elevation in stress-induced glucocorticoid secretion. In addition, the stress-induced rise in plasma corticosterone was accompanied by a significant decrease in maternal levels of corticosteroid binding globulin which suggests increased circulating levels of free corticosterone. Significant stress-induced elevations in plasma corticosterone also occurred in fetuses that were examined on gestation day 20. Furthermore, a significant positive correlation was found between maternal and fetal plasma corticosterone. Results demonstrate that repeated exposure to uncontrollable stress increases plasma concentrations of glucocorticoids throughout pregnancy. In the unbound state, corticosterone may be highly effective in producing alterations in brain development of offspring. These data have important implications for understanding the process underlying the effects of prenatal stress.

Animals↗

PubMed1998

The BALB/c mouse as an animal model for progressive sensorineural hearing loss.

To develop the BALB/c mouse strain as an animal model for the study of progressive sensorineural hearing loss, mice ranging in age from young adult through middle age were studied. Auditory brainstem response thresholds, histopathology [cytocochleograms for hair cells, the packing density of spiral ganglion cells (SGCs), the number of neurons and overall size of the anterior ventral cochlear nucleus (AVCN)], and behavioral paradigms (prepulse inhibition, fear-potentiated startle) were compared with previous data from C57BL/6J (C57) and DBA/2J (DBA) mouse strains. Progressive high frequency hearing loss in BALB/c mice was generally more rapid than C57 and slower than DBA (e.g. mean thresholds for 16 kHz: 10-month-old BALB/c mice = 71 dB SPL; 55-day-old DBA mice = 79 dB SPL; 12-month-old C57 mice = 50 dB SPL). Like the other strains, BALB/c exhibited a progressive loss of hair cells and SGCs that was most severe in the cochlear base and least severe in the middle turns; however, BALB/c mice had relatively more SGC loss in the apex. Unlike C57 and DBA, no loss of neurons was observed in the AVCN following cochlear pathology (although AVCN volume was reduced). Like the other strains, successful fear conditioning was obtained with a 12 kHz conditioned stimulus. Prepulse inhibition showed that middle and low frequency tones (4-12 kHz) became more salient as high frequency hearing declined. Similar results had been previously obtained with C57 and DBA mice and were interpreted as reflecting hearing-loss-induced plasticity in the central auditory system.

Acoustic Stimulation↗

PubMed1998

Exposure to an augmented acoustic environment alters auditory function in hearing-impaired DBA/2J mice.

The effects of exposure to an augmented acoustic environment (AAE) on auditory function were evaluated using DBA/2J (DBA) mice, a strain that exhibits high-frequency hearing loss beginning around the time of weaning/adolescence (between 3-4 weeks of age) and becoming severe by 2-3 months of age. Mice were exposed 12 h per night for 10 nights to a 70 dB SPL broad-band noise AAE at one of three age periods ranging from the onset of hearing loss (25-35 days of age) to more severe degrees of hearing loss (35-45 days and 45-55 days); control mice did not receive the AAE. C57BL/6J (C57) mice of the same ages provided normal-hearing. age-matched mice in both exposed and control conditions. The auditory brainstem response (ABR), acoustic startle response amplitude, and prepulse inhibition (PPI) were used to assess the auditory system. The AAE had significant effects on DBA mice, but had no effect on normal-hearing C57 mice. For the most part, AAE exposure resulted in improved auditory performance in DBA mice (better PPI, lower ABR thresholds, bigger startle amplitudes). However, the age of the mice and/or severity of hearing loss proved to be an important variable; improvement of PPI occurred only when the AAE was initiated later in the course of hearing loss (35 days of age or older); in contrast to this, beneficial effects on ABR thresholds occurred only when the AAE was initiated early in the course of hearing loss (< 45 days of age).

Acoustic Stimulation↗

PubMed1998

The effect of therapeutic touch on pain and anxiety in burn patients.

The purpose of this single-blinded randomized clinical trial was to determine whether therapeutic touch (TT) versus sham TT could produce greater pain relief as an adjunct to narcotic analgesia, a greater reduction in anxiety, and alterations in plasma T-lymphocyte concentrations among burn patients. Therapeutic touch is an intervention in which human energies are therapeutically manipulated, a practice conceptually supported by Rogers' (1970) theory of unitary human beings. Data were collected at a university burn centre in the south-eastern United States. The subjects were 99 men and women between the ages of 15 and 68 hospitalized for severe burns, and they received either TT or sham TT once a day for 5 days. Baseline data were collected on day 1, data were collected before and after treatment on day 3, and post-intervention data were collected on day 6. Instruments included the McGill Pain Questionnaire, Visual Analogue Scales for Pain, Anxiety and Satisfaction with Therapy, and an Effectiveness of Therapy Form. Blood was drawn on days 1 and 6 for lymphocyte subset analysis. Medication usage for pain in mean morphine equivalents, and mean doses per day of sleep, anxiety and antidepressant medications were recorded. Subjects who received TT reported significantly greater reduction in pain on the McGill Pain Questionnaire Pain Rating Index and Number of Words Chosen and greater reduction in anxiety on the Visual Analogue Scale for Anxiety than did those who received sham TT. Lymphocyte subset analyses on blood from 11 subjects showed a decreasing total CD8 + lymphocyte concentration for the TT group. There was no statistically significant difference between groups on medication usage.

Adolescent↗

PubMed1998

Usefulness of D-dimer, blood gas, and respiratory rate measurements for excluding pulmonary embolism.

BACKGROUND: A study was undertaken to assess the usefulness of the SimpliRED D-dimer test, arterial oxygen tension, and respiratory rate measurement for excluding pulmonary embolism (PE) and venous thromboembolism (VTE). METHODS: Lung scans were performed in 517 consecutive medical inpatients with suspected acute PE over a one year period. Predetermined end points for objectively diagnosed PE in order of precedence were (1) a post mortem diagnosis, (2) a positive pulmonary angiogram, (3) a high probability ventilation perfusion lung scan when the pretest probability was also high, and (4) the unanimous opinion of an adjudication committee. Deep vein thrombosis (DVT) was diagnosed by standard ultrasound and venography. RESULTS: A total of 40 cases of PE and 37 cases of DVT were objectively diagnosed. The predictive value of a negative SimpliRED test for excluding objectively diagnosed PE was 0.99 (error rate 2/249), that of PaO2 of > or = 80 mm Hg (10.7 kPa) was 0.97 (error rate 5/160), and that of a respiratory rate of < or = 20/min was 0.95 (error rate 14/308). The best combination of findings for excluding PE was a negative SimpliRED test and PaO2 > or = 80 mm Hg, which gave a predictive value of 1.0 (error rate 0/93). The predictive value of a negative SimpliRED test for excluding VTE was 0.98 (error rate 5/249). CONCLUSIONS: All three of these observations are helpful in excluding PE. When any two parameters were normal, PE was very unlikely. In patients with a negative SimpliRED test and PaO2 of > or = 80 mm Hg a lung scan is usually unnecessary. Application of this approach for triage in the preliminary assessment of suspected PE could lead to a reduced rate of false positive diagnoses and considerable resource savings.

Antifibrinolytic Agents↗

PubMed1997

Effectiveness of computer-assisted instruction in increasing the rate of universal precautions--related behaviors.

BACKGROUND: With widespread noncompliance to universal precautions well established, an experimental study was designed to compare the rate of universal precautions--related behaviors between nurses who participate in computer-assisted instruction. This study also explored the relationship between rates of universal precautions--related behaviors and subjects' demographic and experiential characteristics and history of occupational blood-borne exposure. METHODS: Data were collected by using a questionnaire to elicit information as to subjects' demographic and experiential characteristics and history of occupational blood-borne exposure. The Universal Precautions Assessment Tool was used to gather data on rates of universal precautions--related behaviors on two groups of registered nurses with 30 subjects per group. RESULTS: By using analysis of variance, the null hypothesis was rejected. The intervention used in this study did increase universal precautions--related behaviors. Multiple regression was used to analyze the research question and none of the variables were significant. Forty (67.8%) subjects reported receiving a needlestick or cut caused by a needle or sharp that was actually or potentially contaminated with blood or body fluids. Of these exposures, only one patient was known to be HIV antibody positive. CONCLUSION: Replication studies using computer-assisted instruction interventions are needed as are studies aimed at exploring other potentially effective interventions.

Adult↗

PubMed1997

Characterization of three loci controlling resistance of Arabidopsis thaliana accession Ms-0 to two powdery mildew diseases.

Arabidopsis thaliana accession La-er was susceptible, and accession Ms-0 was resistant, to powdery mildew diseases caused by Erysiphe cruciferarum UEA1 and E. cichoracearum UCSC1. The resistance reaction phenotype of A. thaliana Ms-0 to both pathogens was characterized, and the resistance loci were genetically mapped. Growth of E. cruciferarum UEA1 on Ms-0 leaves was arrested after formation of the first appressorium: the underlying host epidermal cell collapsed, and occasionally there was necrosis of one or two host mesophyll cells. Growth of E. cichoracearum UCSC1 on Ms-0 leaves was arrested after emergence of several germ tubes from the conidium, and there was necrosis of host mesophyll cells at the sites of infection. Examination of F2 progeny of a cross La-er x Ms-0 indicated that two independently-segregating dominant loci were required for resistance to E. cruciferarum UEA1. One locus, named RPW6, was genetically mapped to chromosome 5, in a 5.6 cM interval flanked by pCITf16 and PI. The other locus, named RPW7, mapped to chromosome 3 in a 8.5 cM interval flanked by CDC2A and AFC1. Independent effects of RPW6 and RPW7 on E. cruciferarum UEA1 could be detected by quantitative measurements of growth of mycelium and production of conidia. Resistance to E. cichoracearum UCSC1 mapped to a single locus, named RPW8, at a location on chromosome 3 which we could not distinguish from RPW7. Evidently, RPW7 and RPW8 define either a complex resistance locus, or a common resistance gene with dual specificity.

Arabidopsis↗

PubMed1997

A pragmatic approach to estimating total analytical error of immunoassays.

Several groups have recently commented on the need for more realistic information on analytical performance of laboratory tests. The term "total analytical error" is sometimes used in this context. However, differing opinions have been expressed on how best to obtain estimates of clinical assay error, as it would be perceived by clinicians. We suggest a pragmatic definition of total analytical error for immunoassays and describe our attempts to estimate it by simple designs in the internal quality-control process. We use results over 29 months from a total serum thyroxine RIA. The most important error sources were those related to calibration materials and operator effects, errors not usually captured by short-term or snapshot experiments.

Humans↗

PubMed1997

Fear-potentiated startle in two strains of inbred mice.

The fear-potentiated startle paradigm has been used with great success to examine conditioned fear in both rats and humans. The purpose of this study was to examine fear-potentiated startle in inbred mice. One-month-old C57BL/6J (C57) and DBA/2J (DBA) mice were given tone + foot shock training trials. The amplitude of the acoustic startle reflex was measured in the presence and absence of the tone both before and after training. Both strains showed fear-potentiated startle after training as evidenced by larger startle amplitudes in the presence of the tone than in its absence. However, the magnitude of fear-potentiated startle was greater in DBA mice than in C57 mice. These results not only demonstrate fear-potentiated startle in mice for the first time but also suggest that fear-potentiated startle can be influenced by characteristics of the mouse strain.

Acoustic Stimulation↗