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Biomedical subjects

D Murphy

Publications and source records attributed to D Murphy.

At least 433 records · Page 24Linked to original sources
PubMedDate not supplied

Fructosamine measurement in ponies: validation and response following experimental cyathostome infection.

Validation of an assay for measurement of fructosamine in equine serum and plasma utilised blood samples collected from 24 British native breed ponies. The results indicated that fructosamine can be measured easily using an assay which is precise and accurate. Paired plasma and serum fructosamine measurements were highly correlated, however, greater variations were observed within serum compared with those in plasma. A reference range for fructosamine in plasma was calculated to be 256.9 +/- 60.6 mumol litre-1 (mean +/- 2 SD). In order to assess the fructosamine response following experimental cyathostome infection, nine British native breed ponies were allocated to one of three groups: Group 1 (3.9 million third-stage cyathostome larvae (L3) over a nine-week-period), Group 2 (3.15 million L3 over seven weeks) and Group 3 (uninfected controls). From four weeks prior to infection, blood was obtained, once weekly, from all animals for measurement of plasma fructosamine, plasma albumin and serum globulin concentrations. Plasma fructosamine concentrations decreased in all infected ponies post-infection due to enteric protein loss and/or altered protein composition and/or increased protein turnover.

Aging↗
PubMedDate not supplied

Breath hydrogen measurement in ponies: a preliminary study.

The aim of this study was to establish the normal patterns of breath hydrogen excretion in adult ponies following either voluntary consumption or administration per stomach tube of a test meal/carbohydrate substrate. After an overnight fast, the ponies (n = 7) received either no test meal (ie fasted), glucose, xylose, lactose, lactulose, wheat flour or oats. Exhaled breath samples were collected in duplicate at 0 minutes and at 30-minute intervals thereafter for eight hours. Analysis of duplicate breath hydrogen measurements (n = 714) indicated that the breath hydrogen collection/storage method was reliable. Fasting resulted in negligible levels of breath hydrogen excretion. Increases in breath hydrogen concentration greater than 10 ppm, sustained for at least 30 minutes, were regarded as being biologically significantly different than fasting data and were observed for all ponies following the ingestion of oats or the administration of wheat flour, for three ponies following the administration of glucose and xylose and for two ponies following the administration of lactulose and lactose. The pattern of breath hydrogen excretion was subject to variation between animals following the ingestion of identical test meals. This study provides evidence of incomplete glucose absorption in healthy ponies and indicates that ingestion of non-absorbable carbohydrates do not always result in hydrogen excretion.

Animals↗
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Intraoperative epicardial echocardiography with a miniature high-frequency transducer: imaging techniques and scanning planes.

Intraoperative Doppler echocardiography has the potential to provide anatomic and functional information but is hindered by the large size of standard transducers. We describe new scanning planes accessible through the application of a new 5 MHz miniature transducer with imaging, Doppler, and color-flow capability. Epicardial echocardiography was performed in 15 adults undergoing elective coronary artery bypass grafting. Standard parasternal equivalent, subcostal equivalent, aortopulmonary sulcus and aortosuperior vena caval views were obtained. Previously unobtainable apical four-chamber, five-chamber, and long-axis views were possible by positioning the transducer at the apex. The transducer has a broad bandwidth, allowing high-quality imaging at different depths and could be maneuvered laterally, posteriorly, and over the aorta and pulmonary arteries to provide off-axis views. The proximal-mid coronary arteries were imaged on the beating heart with a standoff medium. Transducer miniaturization should expand the role of epicardial ultrasonography in the surgical management of heart disorders.

Adult↗
PubMedDate not supplied

Prehospital blood transfusion versus crystalloid alone in the air medical transport of trauma patients.

INTRODUCTION: Differences in prehospital resuscitation measures and outcomes of trauma patients transported by two air medical programs were assessed comparing the prehospital administration of crystalloid only (Group A) with the administration of 2 liters of crystalloid followed by blood (Group B). METHODS: A 1-year retrospective review of flight and hospital records of patients taken to Level I trauma centers by two separate air medical programs was completed. Physiologic variables, total fluids infused, and flight times were compared. RESULTS: Thirty-one patients (Group A) received crystalloids in flight, and 17 patients received in-flight blood (Group B). No statistical differences were found between the two groups when comparing age, ISS, PS, RTS, GCS, survival, and total fluid volume. Group B had statistically greater mean flight times compared with Group A (P < .05). A difference was demonstrated between groups A and B in pH and HCO3 measurements (P < .05), with Group B presenting in a more acidotic state on admission to the hospital. CONCLUSION: Patients with lengthy flight times, despite the administration of blood products, presented to the trauma center more acidotic than trauma patients receiving only crystalloid. The true impact of blood products on outcome could not be demonstrated because of statistical differences in flight times between the groups. A multicenter study matching flight times, head injury status, and flight type of assess benefit of prehospital utilization of blood products is warranted.

Adult↗
PubMedDate not supplied

Metabolism of tert-butylhydroquinone to S-substituted conjugates in the male Fischer 344 rat.

tert-Butyl-4-hydroxyanisole (BHA) and its demethylated analog, tert-butyl-hydroquinone (TBHQ), are antioxidants used in food. Both BHA and TBHQ have been shown to promote kidney and bladder carcinogenesis in the rat. We have previously demonstrated that glutathione (GSH) conjugates of a variety of hydroquinones are nephrotoxic and proposed that GSH conjugation serves to target these compounds to the kidney. In the present study, we examined the metabolism of TBHQ, focusing on the formation of potentially nephrotoxic sulfur-containing metabolites. 2-tert-Butyl-5-glutathion-S-ylhydroquinone, 2-tert-butyl-6-glutathion-S-ylhydroquinone, and 2-tert-butyl-3,6-bisglutathion-S-ylhydroquinone were identified as biliary metabolites of TBHQ (1.0 mmol/kg, ip) in male F344 rats, accounting for 2.2% of the dose. Liquid chromatography/mass spectroscopic analysis of urine also revealed the presence of additional sulfur-containing metabolites, tentatively identified as 2,5-dihydroxy-3-tert-butyl-thiophenol, 2,5-dihydroxy-4-tert-butylthiophenol, and their S-methyl derivatives. No mercapturic acids of TBHQ were found in the urine. The major biliary and urinary metabolites were TBHQ-glucuronide and TBHQ-sulfate, with a trace of TBHQ excreted unchanged. The results indicate that TBHQ undergoes oxidation and GSH conjugation in vivo in the male F344 rat. These conjugates are excreted into bile and undergo further metabolism prior to excretion in urine. Formation of the S-containing metabolites of TBHQ may occur in amounts sufficient to play a role in the toxicity of TBHQ to kidney and bladder.

Animals↗
PubMedDate not supplied

Activation of a Qa/Tla class I major histocompatibility antigen gene is a general feature of oncogenesis in the mouse.

A cDNA clone corresponding to a mRNA present at elevated levels in transformed fibroblasts encodes a Qa/Tla class I major histocompatibility complex (MHC) antigen. High levels of this mRNA are found in all tumour cells tested; the transcript can undergo alternative splicing; and a repetitive sequence within the transcription unit has the characteristics of a transposable element. The immunological implications of MHC gene activation in tumour cells are discussed.

Animals↗
PubMedDate not supplied

The class I major histocompatibility antigen gene activated in a line of SV40-transformed mouse cells is H-2Dd, not Qa/Tla.

We have previously described several complementary DNA clones isolated because they correspond to messenger RNAs present at higher levels in the simian virus 40 (SV40)-transformed BALB/c 3T3 cell line SV3T3 Cl38 than in the normal, parental BALB/c 3T3 line. One of these clones, pAG64, hybridizes to RNAs which, while present in BALB/c 3T3 cells, are 10-20-fold more abundant in SV3T3 Cl38 and are found at high levels in a wide variety of transformed cell lines. Nucleotide sequence analysis showed that pAG64 encodes a class I antigen of the major histocompatibility complex. To ascertain the identity of pAG64, we compared its sequence with the available sequences of d haplotype class I antigen genes [K locus, L locus, D locus and the Qa gene defined by genomic clone 27.1] and found that it showed multiple clustered differences from each of these sequences. We therefore concluded that it was not derived from the H-2Kd, H-2Ld or H-2Dd genes and thus must correspond to one of the other class I antigen genes, namely those of the Qa/Tla complex, although it was clearly not the Qa gene defined by the genomic clone 27.1. We now report subsequent findings which indicate that pAG64 in fact corresponds to the H-2Dd gene and not to a Qa/Tla gene.

Animals↗
PubMedDate not supplied

Health care access: a consumer perspective.

This article describes the use of action research as an information base for policy formulation by a collaborative partnership in Spokane, Washington. Health and social service providers recognized access to care by uninsured persons as a major community issue. Little was known from the consumers' perspective about factors limiting access. No benchmarks existed against which to measure progress. Investigators collected mailed surveys from 475 residents of six Spokane neighborhoods and 97 persons participated in 12 focus group sessions. Income, education, and ethnicity were primary factors affecting perceptions of degree to which medical, dental, and mental health needs were being met. Many residents were unable to obtain needed health care; low-cost dental and mental health services were named as their highest priorities. Quality of care, relationships with providers, immediacy of access, and cost were important concerns. Major barriers were cost, length of time before one could get an appointment, lack of comfort with providers, and having to miss work for appointments. Consumer input is critical in understanding local issues in health care. Action research that combines qualitative and quantitative data enhanced practice/policy decisions through assuring ownership of the research and immediate use of findings by involved agencies.

Consumer Behavior↗
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Participation of the central cholinergic system in blood pressure regulation in the Dahl rat model of essential hypertension.

Participation of the cholinergic system in the regulation of blood pressure (BP) in the Dahl salt-sensitive (DS) and salt-resistant (DR) rat model of essential hypertension was investigated. It was found that systemic administration of 0.25 or 0.50 mg/kg physostigmine (PSTG) to unanesthetized, normotensive DS and DR rats caused a significant elevation in BP but did not affect heart rate. At both dose levels, the pressor response was markedly greater and significantly longer in DS rats than in DR rats. The response in both DS and DR rats was blocked by pretreatment with atropine sulfate but not with atropine methylnitrate. These results suggest that the pressor effects of PSTG are mediated by central cholinergic mechanisms, and enhanced central cholinergic activity may participate in the pathogenesis of hypertension in the DS rat.

Animals↗
PubMedDate not supplied

Biomechanical comparison of seven internal fixation devices for the lumbosacral junction.

For comparison purposes, seven different internal fixation systems were applied sequentially to each of six fresh-frozen cadaver spines at the lumbosacral junction. The spines were loaded to a maximum flexion bending moment of 12 Newton meters and an extension moment of 6 Nm. Resultant angular motion was recorded with an electrogoniometer. The Synthes and Kaneda devices provided the most rigid fixation in flexion and extension testing. The Luque internal fixation system was as effective as the Kaneda and Synthes systems at limiting extension but was slightly less successful at limiting flexion. The Knodt system was effective at limiting extension but less effective in limiting flexion. The interfacet screws were effective at limiting flexion but less effective at limiting extension. Harrington rods to the sacral alae were the least effective system in both directions. Sublaminar wires did little to improve their performance.

Biomechanical Phenomena↗
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Hypothalamic pituitary function testing on children receiving carbamazepine or sodium valproate.

An investigation of hypothalamic pituitary axis (HPA) function was performed on children and adolescents receiving long-term monotherapy with either carbamazepine (CBZ) or sodium valproate (NaV). There was a significant reduction in total T4 in the CBZ group. Free T4, T3, and thyroid-stimulating hormone response to thyrotropin-releasing hormone were similar in both groups. All patients produced an adequate growth hormone response to either arginine or L-Dopa. Basal cortisol levels were similar in both groups. An appropriately increased response in luteinising hormone, prolactin, testosterone, and oestradiol occurred in those after puberty. The results suggest that HPA function in children is not compromised by long-term monotherapy with CBZ or NaV.

Adolescent↗
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Can sharp waves localized at the sphenoidal electrode accurately identify a mesio-temporal epileptogenic focus?

In our patient population that had undergone antero-temporal lobectomy, we found 20 patients with a unilateral sphenoidal/antero-temporal interictal focus. All patients had normal computed tomography (CT) scans. Invasive recordings with subdural electrode arrays placed over and under the temporal lobe were used in every patient. We found that the scalp interictal focus predicted for all patients that both the interictal sharp waves and ictal onset would be mesiobasal/anterotemporal in location on the subdural arrays. Seventy-five percent of these patients had an excellent outcome with temporal lobectomy.

Adult↗
PubMedDate not supplied

Significance of sharp waves in routine EEGs after epilepsy surgery.

We retrospectively analyzed the presence of sharp waves in 2-h EEGs performed 6 months after epilepsy surgery in 59 patients. To study the significance of the postoperative interictal epileptiform activity in the tissue remaining after resection, we included only patients with a single epileptic focus (as defined preoperatively by prolonged video/EEG recordings and subdural electrode arrays studies) and no progressive structural lesions. Temporal lobectomy was performed in 51 patients (86%); extratemporal resections were performed in the remainder. The epileptogenic focus was completely resected in 26 patients (44%). The immediate postoperative electrocorticograms (EcoG) showed spikes in 13 patients (22%). At 6-month follow-up, 43 patients (73%) were seizure-free or had auras only and 12 patients (20%) had epileptiform activity on EEG. A significant correlation was noted between presence of sharp waves in the 6-month postoperative EEG and recurrence of seizures (Fisher's exact test p = 0.011) and also with the extent of the resection (complete vs. incomplete p = 0.042). We noted no correlation between postoperative epileptiform activity and location of the resection (temporal vs. extratemporal), presence of spikes in immediate postoperative EcoG, or occurrence of auras only at 6-month follow-up.

Adolescent↗
PubMedDate not supplied

Quantitative analysis of seizure frequency 1 week and 6, 12, and 24 months after surgery of epilepsy.

We made quantitative analysis of seizure frequency 1 week and 6, 12, and 24 months after seizure surgery. Seizure recurrence was significantly higher when seizures occurred in the first postoperative week. Seizure recurrence increased progressively with longer follow-ups, but the 6 month postoperative follow-up period was an excellent index of long-term outcome. In operative follow-up studies, seizure frequency should be reported at fixed follow-up periods, e.g., at 6 months and 1, 2, 5, and 10 years. Meaningful comparison of outcomes between different studies is possible only when reports include outcome at fixed postoperative follow-up periods (as opposed to ranges of follow-up periods).

Chi-Square Distribution↗
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Intracarotid amobarbital (Wada) test for language dominance: correlation with results of cortical stimulation.

Eighty-eight patients had bilateral intracarotid amobarbital (Wada) testing to determine hemispheric dominance for language in preparation for epilepsy surgery, as well as unilateral extraoperative cortical electrical stimulation using subdural electrode arrays. In none of the patients with left dominance by Wada testing were language areas found with right-sided stimulation, but two patients with right dominance by Wada testing had language areas mapped on the left side. These findings suggest that left dominance by Wada testing is strong evidence for exclusive lateralization of language function in the left hemisphere, but there is concern about the ability of the Wada test to exclude the possibility of some left-sided language function despite apparent right-sided dominance. Patients with left dominance on Wada testing do not need cortical stimulation before extensive right temporal lobectomy, but we believe that patients with right or bilateral dominance on Wada testing should have cortical stimulation for localization of language areas if extensive left or right temporal or frontal resection is planned.

Amobarbital↗
PubMedDate not supplied

Situs revisited: imaging of the heterotaxy syndrome.

Situs anomalies present a diagnostic challenge to radiologists because of the overlapping spectrum of findings commonly seen in asplenia and polysplenia. In a series of 21 patients with a diagnosis of heterotaxy syndrome, all 11 asplenic patients and seven of 10 polysplenic patients had congenital heart disease. Although there was a variety of complex congenital heart disease, the most common type in both patient groups was a common atrioventricular canal. In both groups, the laterality of the aorta and stomach was quite variable, but intestinal malrotation was a constant feature. In 11 asplenic patients, the most frequent findings were a bridging liver (10 cases), absent spleen (10 cases), and left-sided inferior vena cava (nine cases). Only seven of these patients had an aorta ipsilateral to the inferior vena cava, contrary to previous thought that this finding was specific for asplenia. In the 10 polysplenic patients, bridging livers were less frequent (five cases), single (six cases) or multiple (four cases) spleens were seen, and azygous continuation with interruption of the inferior vena cava was usually present (eight cases). Although not pathognomonic of polysplenia, inferior vena cava interruption with azygous or hemiazygous continuation is the most common anatomic finding of this condition. Although the terms asplenia and polysplenia are helpful in suggesting the typical anatomy, both syndromes encompass an overlapping spectrum that needs to be described individually and may best be called heterotaxy syndrome.

Abnormalities, Multiple↗