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Biomedical subjects

J Barnard

Publications and source records attributed to J Barnard.

At least 19 recordsLinked to original sources
PubMed2005

Donor heart selection: Wythenshawe experience.

BACKGROUND: The decline in the number of suitable donor hearts has led to an increasing interest in the use of previously unacceptable donors. This study aimed to evaluate the outcome of recipients of donor hearts considered medically unsuitable for transplantation at this center that were used in other centers in the United Kingdom. METHODS: Forty donor hearts (group 1) were declined by Wythenshawe Hospital and used in other units in the United Kingdom in the period extending from April 1998 to March 2003. One hundred four hearts (group 2) were transplanted at Wythenshawe Hospital during the same period. Donors and recipient data were obtained from the United Kingdom Cardiothoracic Transplant Audit database. Mortality in both groups was analyzed using SPSS software. RESULTS: Mortality in patients receiving grafts from group 1 donors was significantly higher than in group 2 (P < .0009). Of the early deaths in this group 50% (6 of 12) were the result of graft failure. These donors were receiving high doses of inotropes, had ischemic time exceeding 3.5 hours, and the grafts were transplanted into high-risk patients. CONCLUSION: Hearts declined on medical grounds by one center should be evaluated with caution before being considered suitable for transplantation, especially when more than one adverse factor is present.

England↗
PubMed2004

Does bispectral analysis of the electroencephalogram add anything but complexity?

BACKGROUND: Analysis of the bispectrum of EEG waveforms is a component of the proprietary BIS index-a commonly used commercial monitor of depth of anaesthesia. Does the use of the bispectrum give more information about depth of anaesthesia than the power spectrum? METHODS: We collected and analysed EEG waveforms during induction of general anaesthesia in 39 patients, comparing the changes in bispectral parameter (SynchFastSlow), with an analogous power spectrum-based parameter (PowerFastSlow). Both compare the logarithmic ratio of high frequency components (40-47 Hz) with the total (1-47 Hz). Because the changes in bispectrum are affected by signal amplitude, we also calculated a third parameter (SFSbicoh) from the bicoherence, which is an amplitude-independent statistic. RESULTS: The SynchFastSlow and PowerFastSlow were correlated (r=0.84) and neither was superior in predicting the awake or anaesthetized state (area under receiver operating characteristic curves = 0.85 vs 0.93). There was no change in the SFSbicoh over the induction period, and it did not correlate with SynchFastSlow (r=0.07). CONCLUSIONS: We could not show that bispectral analysis gave more information than power spectral-based analysis. Most of the changes in the bispectral values result from decreases in the relative high frequency content of the EEG caused by anaesthesia.

Adult↗
PubMed2004

Modeling of Escherichia coli inactivation by UV irradiation at different pH values in apple cider.

This study examined the effects and interactions of UV light dose (1,800 to 20,331 microJ/cm2) and apple cider pH (2.99 to 4.41) on the inactivation of Escherichia coli ATCC 25922, a surrogate for E. coli O157:H7. A predictive model was developed to relate the log reduction factor of E. coli ATCC 25922 to the UV dose. Bacterial populations for treated and untreated samples were enumerated with the use of nonselective media. The results revealed that UV dose was highly significant in the inactivation of E. coli, whereas pH showed no significant effect at higher UV doses. Doses of 6,500 microJ/cm2 or more were sufficient to achieve a greater than 5-log reduction of E. coli. Experimental inactivation data were fitted adequately by a logistic regression model. UV irradiation is an attractive alternative to conventional methods for reducing bacteria in unpasteurized apple cider.

Beverages↗
PubMed2003

Nociceptive and anaesthetic-induced changes in pulse transit time during general anaesthesia.

BACKGROUND: Pulse transit time (rPTT), the interval between ventricular electrical activity and arrival of a peripheral pulse waveform, has been used to detect changes in autonomic tone. The aim of this observational pilot study was to measure changes in rPTT in response to general anaesthesia and noxious stimuli. METHODS: Thirty-one healthy women undergoing gynaecological surgery were allocated to groups depending on the need for airway management with tracheal intubation (n=9), a laryngeal mask (LMA, n=17) or a facemask (n=5). During general anaesthesia, we measured changes in RR interval (RR-int) and rPTT after (i) induction of anaesthesia, (ii) airway manipulation and (iii) surgical stimulus. rPTT was estimated as the interval from the peak in the R-wave to detection of the pulse oximeter waveform in the periphery. RESULTS: Mean baseline rPTT was 245 (SD 27) ms. Upon induction of anaesthesia, rPTT increased (by 28.2 (20.4) ms, P<0.001) in all but two patients. rPTT decreased in response to endotracheal intubation (by 43.1 (24.6) ms, P=0.001) but did not vary in response to insertion of LMA or surgical stimulus. Mean baseline RR-int was 865 (141) ms. A mean reduction in RR-int after tracheal intubation did not reach statistical significance. RR-int was unchanged with induction of anaesthesia, LMA insertion or surgical stimulus. CONCLUSION: Variation in rPTT reflects autonomic responses to nociceptive stimulation and fluctuations in anaesthetic depth independently of heart rate.

Adult↗
PubMed2003

Implicit memory formation in sedated ICU patients after cardiac surgery.

BACKGROUND: Recent research into memory formation under sedation has generated conflicting results. We investigated explicit and implicit memory in ICU patients during moderate to deep propofol sedation following cardiac surgery. METHODS: Two different methods of memory testing were used; (1). free-association (F-A) word-pair testing (n=33) to test conceptual implicit memory and (2). process dissociation procedure (PDP) (n=26) to detect perceptual implicit and explicit memory. One hour after surgery, whilst sedated, the F-A group received one of two lists of 10 category-exemplar word-pairs through headphones, while the PDP group was presented with one of two lists of 16 five-letter words. When awake and co-operative, the F-A group was tested using F-A testing, and the PDP group was tested using the PDP. RESULTS: The F-A group had a mean (SD) correct response rate of 7 (9)% for the target list, and 9 (8)% for the distractor list. The PDP group had a mean (SD) correct response rate of 11 (14) and 10 (13)% for the inclusion and exclusion lists, respectively, with mean correct response rates of 13 (14)% for both the corresponding distractor lists. Neither group showed any significant differences between their responses and a list of distractor words (Wilcoxon tests). CONCLUSION: We found no evidence for memory formation in post-cardiac surgery patients under moderate to deep propofol sedation.

Adult↗
PubMed2002

The radiation resistance of ascospores and sclerotia of Pyronema domesticum.

The Food and Drug Administration has become aware of several instances where supposedly sterile medical surgical products made of Chinese cotton have been found to contain viable Pyronema domesticum. The aim of this research was to determine the gamma and electron beam radiation resistance values for the two dormant phases (ascospores and sclerotia) of P. domesticum. The resistance values were obtained by developing a standardized system to cultivate, purify, and harvest biological indicators containing sclerotia or ascospores. Ascospores were more resistant to radiation than sclerotia. The D(10) values for sclerotia were 0.79 and 1.09 kGy for strains 32030 and 14881, respectively. The resistance value for wild type ascospores was 2.83 kGy. The current standard for assuring radiation sterilization of medical devices is ISO 11137. This standard was developed to address the propensity for highly radiation-resistant organisms such as P. domesticum. Prior to the standard, biological indicators such as Bacillus pumilus, having a nominal D(10) value or 1.7 kGy, were used to determine the sterility of many medical devices.

Ascomycota↗
PubMed2002

Variations in implementation of current national guidelines for the treatment of acute pancreatitis: implications for acute surgical service provision.

OBJECTIVES: The aim of this study was to explore the implementation of the current national guidelines for the treatment of acute pancreatitis. By taking pooled data from all available individual and regional audits, the study aimed to identify areas of consistent variance from the 'best practice' stipulated in the guidelines. METHODS: All published audits of the management of acute pancreatitis where treatment was compared to the current British Society of Gastroenterology guidelines for the treatment of acute pancreatitis were identified from a search of MEDLINE and the published abstracts of relevant specialty meetings. RESULTS: Five audits providing pooled data on 545 patients were identified. Overall mortality from severe disease was 8% (range, 4-17%). Definitive treatment of gallstone disease within 4 weeks of index attack was performed in 49% (range, 16-65%). High dependency or intensive care facilities for severe disease were available in 52% (range, 20-100%). CONCLUSION: This study demonstrates the presence of striking variations in the implementation of the current national guidelines for the treatment of acute pancreatitis.

Acute Disease↗
PubMed2001

Familial aggregation of sarcoidosis. A case-control etiologic study of sarcoidosis (ACCESS).

Despite reports of familial clustering of sarcoidosis, little empirical evidence exists that disease risk in family members of sarcoidosis cases is greater than that in the general population. To address this question, we estimated sarcoidosis familial relative risk using data on disease occurrence in 10,862 first- and 17,047 second-degree relatives of 706 age, sex, race, and geographically matched cases and controls who participated in the multicenter ACCESS (A Case-Control Etiology Study of Sarcoidosis) study from 1996 to 1999. Familial relative risk estimates were calculated using a logistic regression technique that accounted for the dependence between relatives. Sibs had the highest relative risk (odds ratio [OR] = 5.8; 95% confidence interval [CI] = 2.1-15.9), followed by avuncular relationships (OR = 5.7; 95% CI = 1.6-20.7), grandparents (OR = 5.2; 95% CI = 1.5-18.0), and then parents (OR = 3.8; 95% CI = 1.2-11.3). In a multivariate model fit to the parents and sibs data, the familial relative risk adjusted for age, sex, relative class, and shared environment was 4.7 (95% CI = 2.3-9.7). White cases had a markedly higher familial relative risk compared with African-American cases (18.0 versus 2.8; p = 0.098). In summary, a significant elevated risk of sarcoidosis was observed among first- and second-degree relatives of sarcoidosis cases compared with relatives of matched control subjects.

Adolescent↗
PubMed2001

Sarcoidosis: immunology, rheumatic involvement, and therapeutics.

Sarcoidosis is a systemic granulomatous disorder of unknown cause. It has protean manifestations and can affect any organ, including bones, joints, muscles, and vessels. This article reviews the most recent information on the immunologic and inflammatory pathogenesis of sarcoidosis and its implications for therapy. Sarcoidosis results from an overexuberant T cell-mediated immune response to the unknown antigen. This antigen presentation/T cell antigen recognition event occurs in a microenvironment that is suffused in proinflammatory cytokines and growth factors that promote cell attraction, adhesion, permeability changes, further cytokine production, and release. An amplified cellular immune response ensues, leading to granuloma formation and fibrosis. The article summarizes the new developments in the medical literature related to the rheumatologic manifestations and their detection and management in sarcoidosis patients. Osseous involvement in sarcoidosis is often underdiagnosed because it can be asymptomatic. New imaging techniques improve detection. Management of osteoporosis in sarcoidosis patients requires special attention because these patients often have an underlying disorder in calcium metabolism that results in hypercalcuria and hypercalcemia. Joint manifestations, such as the classic Lofgren syndrome with accompanying erythema nodosum, may be self-limited or may become chronic, presenting an ongoing therapeutic challenge. Sarcoidosis vasculitis can be devastating, affecting virtually any vessel in any organ and causing significant morbidity. Muscle involvement, like the bony involvement, is underdiagnosed. Symptoms of muscle weakness, aches, tenderness, and fatigue should prompt consideration of occult sarcoid myositis, often with accompanying neurogenic atrophy. Sarcoidosis treatment usually starts with a period of observation before pharmacologic intervention. Corticosteroids remain the first-line therapy. Alternatives to corticosteroids are often introduced either because of steroid intolerance or in an attempt to reduce steroid dose and side effects. The advantages and disadvantages of these second line therapies are reviewed. Medical vigilance, with attention to new patient symptoms, is important in the management of sarcoidosis, because of the tendency of this disease to present in so many and diverse patterns.

Bone Diseases↗
PubMed2000

Applying conversation analysis to foster accurate reporting in the diet history interview.

Inaccuracy in reporting dietary intakes is a major problem in managing diet-related disease. There is no single best method of dietary assessment, but the diet history lends itself well to the clinical setting. In many diet histories data are collected orally, so analysis of interviews can provide insights into reporting behaviors. Conversation analysis is a qualitative method that describes the systematic organization of talk between people. Patterns are identified and checked for consistency within and among individual interviews. The aim of this study was to describe consistent ways of reporting diet histories and to identify conversational features of problematic reporting. Diet history interviews from 62 overweight and insulin-resistant adult volunteers (50 women, 12 men) attending an outpatient clinic and 14 healthy volunteers (7 men, 7 women) participating in an energy balance study were audiotaped and transcribed. Conversation analysis identified a remarkably consistent pattern of reporting diet histories and 3 conversational features that indicated problematic reporting: "it depends," denoting variability (least of all at breakfast); "probably," suggesting guesswork (related to portion sizes); and elaborated talk on certain foods, distinguishing sensitive topics (e.g., alcohol, chocolate, butter/margarine, take-out foods) from safe topics. These findings indicate that there are ways in which dietetics practitioners may conduct the diet history interview to foster more accurate reporting.

Adult↗
PubMed2000

Fas activation reduces neutrophil adhesion to endothelial cells.

Polymorphonuclear neutrophils (PMN) express apoptotic markers and lose effector functions including adhesion, chemotaxis, and phagocytosis when cultured overnight. Although the loss of function correlates with apoptosis, it is not clear if functions are lost before an early marker of apoptosis, the display of phosphatidylserine (PS), targets PMN for removal by phagocytic cells. To address this question, freshly isolated PMN were treated with Fas-activating antibodies to induce apoptosis rapidly. Early markers of apoptosis and PMA-stimulated adhesion to endothelial cells were measured. After 1 h of Fas exposure, only 16% PMN had externalized PS. In contrast, Fas activation reduced PMA-stimulated adhesion between 68 and 27% depending on PMA concentration. The loss of adhesion was accompanied by a reduction in beta2 integrin expression and receptor clustering. These results indicate that the Fas-induced loss of adhesion may precede PS externalization and could limit participation in the inflammatory response before PS externalization targets PMN for removal.

Animals↗
PubMed1999

Liver transplantation for glycogen storage disease types I, III, and IV.

UNLABELLED: Glycogen storage disease (GSD) types I, III, and IV can be associated with severe liver disease. The possible development of hepatocellular carcinoma and/or hepatic failure make these GSDs potential candidates for liver transplantation. Early diagnosis and initiation of effective dietary therapy have dramatically improved the outcome of GSD type I by reducing the incidence of liver adenoma and renal insufficiency. Nine type I and 3 type III patients have received liver transplants because of poor metabolic control, multiple liver adenomas, or progressive liver failure. Metabolic abnormalities were corrected in all GSD type I and type III patients, while catch-up growth was reported only in two patients. Whether liver transplantation results in reversal and/or prevention of renal disease remains unclear. Neutropenia persisted in both GSDIb patients post liver transplantation necessitating continuous granulocyte colony stimulating factor treatment. Thirteen GSD type IV patients were liver transplanted because of progressive liver cirrhosis and failure. All but one patient have not had neuromuscular or cardiac complications during follow-up periods for as long as 13 years. Four have died within a week and 5 years after transplantation. Caution should be taken in selecting GSD type IV candidates for liver transplantation because of the variable phenotype, which may include life-limiting extrahepatic manifestations. It remains to be evaluated, whether a genotype-phenotype correlation exists for GSD type IV, which may aid in the decision making. CONCLUSION: Liver transplantation should be considered for patients with glycogen storage disease who have developed liver malignancy or hepatic failure, and for type IV patients with the classical and progressive hepatic form.

Adolescent↗
PubMed1999

Identification of neural circuits underlying P300 abnormalities in schizophrenia.

Event-related potentials (ERPs) provide a noninvasive method to evaluate neural activation and cognitive processes in schizophrenia. The pathophysiological significance of these findings would be greatly enhanced if scalp-recorded ERP abnormalities could be related to specific neural circuits and/or regions of the brain. Using quantitative approaches in which scalp-recorded ERP components are correlated with underlying neuroanatomy in schizophrenia, we focused on biophysical and statistical procedures (partial least squares) to relate the auditory P300 component to anatomic measures obtained from quantitative magnetic resonance imaging. These findings are consistent with other evidence that temporal lobe structures contribute to the generation of the scalp-recorded P300 component and that P300 amplitude asymmetry over temporal recording sites on the scalp may reflect anatomic asymmetries in the volume of the superior temporal gyrus in schizophrenia.

Brain Mapping↗