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Biomedical subjects

J A Harris

Publications and source records attributed to J A Harris.

At least 55 records · Page 3Linked to original sources
PubMed1999

Delayed diagnosis of fatal medium-chain acyl-CoA dehydrogenase deficiency in a child.

A 5-year-old white female presented with coma and died unexpectedly. She had a history of recurrent episodes of febrile illnesses associated with lethargy and coma. Postmortem investigation revealed a fatty liver, leading to a suspicion of inborn error of fatty acid oxidation. The diagnosis of medium-chain acyl-CoA dehydrogenase (MCAD) deficiency was suggested by abnormal acylcarnitine profile with increased octanoylcarnitine in the blood, and confirmed by fatty acid oxidation studies and mutation analysis in skin fibroblast cultures. This case emphasizes the need to consider fatty acid oxidation disorders in all children who present with hypoglycemia with absent or mild ketones in the urine and high anion gap metabolic acidosis.

Acidosis↗
PubMed1999

Individual differences in multiple dimensions of aggression: a univariate and multivariate genetic analysis.

Previous behaviour genetic studies of aggression have yielded inconsistent results: reported heritabilities for different types of aggressive behaviour ranging from 0 to 0.98. In the present study, 247 adult twin pairs (183 MZ pairs; 64 same-sex DZ pairs) were administered seven self-report questionnaires which yielded 18 measures of aggression. Univariate genetic analyses showed moderate to high heritabilities for 14 of these 18 measures and for a general aggression factor and three correlated aggression factors extracted from the measures. Multivariate genetic analyses showed sizeable genetic correlations between the different dimensions of aggression. Thus, individual differences in many types of aggressive behaviour are attributable to some extent to genetic factors and there is considerable overlap between the genes that operate on different types of aggressive behaviour.

Adult↗
PubMed1999

Giant colonic diverticulum: report of a case.

Giant colonic diverticulum is a rare complication of colonic diverticulosis. It typically occurs as a single diverticulum located on the antimesenteric border of the sigmoid colon. The most widely accepted theory for its development attributes the progressive dilation to a "ball-valve" mechanism, allowing air to enter but not to exit. Patients usually present complaining of abdominal pain and/or an abdominal mass, although they may remain asymptomatic. Physical examination reveals a tympanic abdominal mass that appears as a round radiolucency on plain radiographs and CT. Barium enema demonstrates the relationship of the diverticulum to bowel and may document communication with the colonic lumen. To alleviate symptoms and prevent complications, the recommended treatment is excision of the diverticulum in continuity with the involved colonic segment. We report a case and discuss the presentation, diagnosis, and management of giant colonic diverticulum.

Aged↗
PubMed1999

Peripheral clear cell cholangiocarcinoma: a rare histologic variant.

We present the case of a 50-year-old diabetic male who underwent open cholecystectomy for acute gangrenous cholecystitis. At the time of exploration, a 1.5-cm mass was found peripherally in the right lobe of his liver, and an incisional biopsy was performed. Microscopic examination revealed a distinct overgrowth of clear cells in an acinar pattern, with tumor cells emerging directly from bile ducts. The tumor cells were periodic acid-Schiff reactive and diastase resistant, indicating the presence of mucin. No bile canaliculi were demonstrated by immunostaining with carcinoembryonic antigen. CT scans of the chest and abdomen were otherwise normal. Based on these microscopic, immunohistochemical, and clinical data, a diagnosis of clear cell cholangiocarcinoma was established. The patient later underwent reexploration and generous hepatic wedge resection. He did well postoperatively and is free of disease after 12 months.

Acute Disease↗
PubMed1999

Splenic flexure volvulus in association with Chilaiditi syndrome: report of a case.

Hepatodiaphragmatic interposition of the intestine, or Chilaiditi syndrome, is uncommon and typically asymptomatic, but it can be associated with symptoms ranging from intermittent, mild abdominal pain to acute intestinal obstruction. Factors such as the interruption or absence of peritoneal attachments and redundant colon with a long mesentery predispose to both Chilaiditi syndrome and colonic volvulus. The presence of hepatodiaphragmatic interposition of the intestine requires no specific treatment in the absence of symptoms. Colonic volvulus in association with Chilaiditi syndrome is treated based on the location of the volvulus. Volvulus of the splenic flexure is typically treated with resection and primary anastomosis. We report only the third case of colonic volvulus in association with Chilaiditi syndrome and the first with volvulus of the splenic flexure.

Adult↗
PubMed1999

Learning through maps: functional significance of topographic organization in primary sensory cortex.

The presence of "maps" in sensory cortex is a hallmark of the mammalian nervous system, but the functional significance of topographic organization has been called into question by physiological studies claiming that patterns of neural behavioral activity transcend topographic boundaries. This paper discusses recent behavioral and physiological studies suggesting that, when animals or human subjects learn perceptual tasks, the neural modifications associated with the learning are distributed according to the spatial arrangement of the primary sensory cortical map. Topographical cortical representations of sensory events, therefore, appear to constitute a true structural framework for information processing and plasticity.

Animals↗
PubMed1998

Seasonal mood change and personality: an investigation of genetic co-morbidity.

Clinical observations and empirical studies suggest that Seasonal Affective Disorder (SAD) is related to personality. The present study estimates the genetic and environmental correlations between the Global Seasonality Score (GSS) from the Seasonal Pattern Assessment Questionnaire and personality measures, assessed using the NEO Five Factor Inventory (NEO-FFI) and the Dimensional Assessment of Personality Pathology (DAPP) in a volunteer sample of 163 monozygotic (MZ) pairs (102 female and 61 male pairs) and 134 dizygotic (DZ) pairs (70 female, 38 male and 26 opposite-sex pairs). Large genetic correlations were found between the GSS and NEO-FFI Neuroticism (0.52: 95% CI = 0.36-0.71) and DAPP-BQ Cognitive Dysregulation (0.50: 95% CI = 0.30-0.71), Affective Lability (0.49: 95% CI = 0.29-0.77), Anxiousness (0.37: 95% CI = 0.18-0.55) and Stimulus Seeking (0.45: 95% CI = 0.25-0.64) scales. The genetic correlations with the remaining scales, such as Extraversion (0.06: 95% CI = -0.16-0.26), Compulsivity (-0.09: 95% CI = -0.31-0.12) and Submissiveness (0.15: 95% CI = -0.05-0.34) were uniformly small. All environmental correlations between the GSS and personality scales were < or = 0.19. These results provide evidence that the observed correlations between these seasonality and personality dimensions are attributable to common genetic factors and that environmental influences are domain specific.

Adolescent↗
PubMed1998

Evidence that GABA transmission mediates context-specific extinction of learned fear.

Six experiments used rats to study the effects of the beta-carboline FG 7142 on extinction of fear responses (freezing) to an auditory cue that had signalled footshock. Subcutaneous injection of FG 7142 interfered with the development of extinction without having any detectable effect on the rats' levels of fear prior to extinction. Injection of FG 7142 also reversed extinction, partially reinstating fear responses that had been extinguished previously. A similar reinstatement of extinguished fear was seen when rats were tested for fear of the cue in a different chamber. The reinstatement produced by FG 7142 and that caused by context shift were not additive: FG 7142 did not increase extinguished fear if rats were tested in the different chamber. Finally, FG 7142 had no detectable effect on the latent inhibition of fear produced by repeatedly presenting the cue alone before conditioning with shock, even though this inhibition, like extinction, was affected by a shift in context. The present findings indicate that GABA transmission at GABA(A) receptors is involved in the inhibition of extinguished fear, and that this effect of GABA is regulated by those cues that constitute the extinction context.

Animals↗
PubMed1998

Requirements for infrastructure and essential activities of infection control and epidemiology in hospitals: A consensus panel report. Society for Healthcare Epidemiology of America.

The scientific basis for claims of efficacy of nosocomial infection surveillance and control programs was established by the Study on the Efficacy of Nosocomial Infection Control project. Subsequent analyses have demonstrated nosocomial infection prevention and control programs to be not only clinically effective but also cost-effective. Although governmental and professional organizations have developed a wide variety of useful recommendations and guidelines for infection control, and apart from general guidance provided by the Joint Commission on Accreditation of Healthcare Organizations, there are surprisingly few recommendations on infrastructure and essential activities for infection control and epidemiology programs. In April 1996, the Society for Healthcare Epidemiology of America established a consensus panel to develop recommendations for optimal infrastructure and essential activities of infection control and epidemiology programs in hospitals. The following report represents the consensus panel's best assessment of needs for a healthy and effective hospital-based infection control and epidemiology program. The recommendations fall into eight categories: managing critical data and information; setting and recommending policies and procedures; compliance with regulations, guidelines, and accreditation requirements; employee health; direct intervention to prevent transmission of infectious diseases; education and training of healthcare workers; personnel resources; and nonpersonnel resources. The consensus panel used an evidence-based approach and categorized recommendations according to modifications of the scheme developed by the Clinical Affairs Committee of the Infectious Diseases Society of America and the Centers for Disease Control and Prevention's Hospital Infection Control Practices Advisory Committee.

Accreditation↗
PubMed1998

Using c-fos as a neural marker of pain.

Just over a decade has past since Hunt et al. reported that the gene c-fos and its protein product Fos are expressed in the spinal cord of rats subjected to peripheral noxious stimulation. These authors showed that noxious stimulation (application of radiant heat or mustard oil) to the hind paw resulted in a massive increase in the expression of Fos in neurons in the dorsal horn of the lumbar spinal cord. Since then, there has been an explosion of studies in which c-fos has been used to study nociception (pain), and the number of such studies increases each year. The net result has been to establish c-fos expression as a valuable tool in pain research. Moreover, recent studies have provided evidence identifying the role of c-fos expression in spinal nociceptive processes. However, there are several important limitations to the practice of using c-fos to study nociception, and these limitations can be easily overlooked as the practice graduates to the status of an established technique. The increasing use of c-fos to study nociception necessitates a critical review of the practice, identifying the shortcomings as well as the strengths of this tool.

Animals↗
PubMed1998

The heritability of testosterone: a study of Dutch adolescent twins and their parents.

The heritability of total plasma testosterone levels, determined from blood samples, was examined in 160 adolescent twin pairs and their parents. Subjects were tested as part of a larger study of cardiovascular risk factors, conducted in Amsterdam. Each subject provided a sample of blood which was assayed to measure testosterone concentrations. Correlations of testosterone in monozygotic twins were higher than in dizygotic twins. No resemblance was found between testosterone values in fathers and those in their children and a moderate correlation was seen between mothers and their daughters. The lack of resemblance between family members of opposite sex suggests that different genetic factors influence plasma testosterone concentrations in men and women. In adolescent men, approximately 60% of the variance in testosterone levels is heritable. The lack of father-son resemblance suggests that different genetic factors may be expressed in adolescence and adulthood. In women, 40% of the variance in testosterone levels is heritable, both in adolescence and in adulthood.

Adolescent↗
PubMed1998

Benzodiazepine-induced amnesia in rats: reinstatement of conditioned performance by noxious stimulation on test.

A benzodiazepine (midazolam), injected either systemically or directly into the basolateral amygdala (BLA), differentially affected the acquisition of fear responses to a shocked context: Administration of the drug before conditioning impaired subsequent freezing to the context but spared analgesic responses in rats tested there for sensitivity to formalin pain. Moreover, the pain test not only revealed evidence for analgesic responses but also served to reinstate conditioned freezing that was otherwise absent in rats conditioned under midazolam. The results were interpreted as showing that the presence of noxious stimulation on test serves either (a) to assist in retrieval of the context-shock association whose storage had been modified by midazolam's action in the BLA, or (b) to enable performance of the context-shock association whose affective properties had been blocked by midazolam's action in the BLA.

Amygdala↗
PubMed1998

The characterisation of polyether ionophore veterinary drugs by HPLC-electrospray MS.

We undertake the determination of a wide range of veterinary drug residues in a range of animal products. Various screening analyses are employed, followed by HPLC-API (atmospheric pressure ionisation)-MS for the unequivocal confirmation of significant positives. EU legislation for the use of GC-MS as a confirmatory technique requires the successful monitoring of at least four diagnostic ions and although no such requirement exists for HPLC-MS confirmation, a similar requirement would seem appropriate. Until recently, reports describing the electrospray MS confirmation of residues of the polyether ionophores have been based on monitoring one or two ions. We have found that the addition of ammonium acetate to the HPLC mobile phase, in conjunction with 'cone voltage' or 'skimmer' assisted fragmentation, is a convenient way of producing additional diagnostic ions from polyether ionophore compounds, without compromising the overall sensitivity. Results for lasalocid, the most widely used compound, are presented. Electrospray MS data and acquisition parameters for lasalocid, monensin, narasin and salinomycin are described. The advantage of this analytical approach is that it may be used to generate confirmatory data using a single quadrupole MS system, without the need for advanced MS instrumentation, e.g., MS-MS.

Animals↗
PubMed1998

Requirements for infrastructure and essential activities of infection control and epidemiology in hospitals: a consensus panel report. Society for Healthcare Epidemiology of America.

The scientific basis for claims of efficacy of nosocomial infection surveillance and control programs was established by the Study on the Efficacy of Nosocomial Infection Control project. Subsequent analyses have demonstrated nosocomial infection prevention and control programs to be not only clinically effective but also cost-effective. Although governmental and professional organizations have developed a wide variety of useful recommendations and guidelines for infection control, and apart from general guidance provided by the Joint Commission on Accreditation of Healthcare Organizations, there are surprisingly few recommendations on infrastructure and essential activities for infection control and epidemiology programs. In April 1996, the Society for Healthcare Epidemiology of America established a consensus panel to develop recommendations for optimal infrastructure and essential activities of infection control and epidemiology programs in hospitals. The following report represents the consensus panel's best assessment of needs for a healthy and effective hospital-based infection control and epidemiology program. The recommendations fall into eight categories: managing critical data and information; setting and recommending policies and procedures; compliance with regulations, guidelines, and accreditation requirements; employee health; direct intervention to prevent transmission of infectious diseases; education and training of healthcare workers; personnel resources; and nonpersonnel resources. The consensus panel used an evidence-based approach and categorized recommendations according to modifications of the scheme developed by the Clinical Affairs Committee of the Infectious Diseases Society of America and the Centers for Disease Control and Prevention's Hospital Infection Control Practices Advisory Committee.

Accreditation↗
PubMed1998

Safety and efficacy of azithromycin in the treatment of community-acquired pneumonia in children.

OBJECTIVE: To compare the safety and efficacy of azithromycin with amoxicillin/clavulanate or erythromycin for the treatment of community-acquired pneumonia, including atypical pneumonia caused by Mycoplasma pneumoniae and Chlamydia pneumoniae. METHODS: Multicenter, parallel group, double blind trial in which patients 6 months to 16 years of age with community-acquired pneumonia were randomized 2:1 to receive either azithromycin for 5 days or conventional therapy for 10 days (amoxicillin/clavulanate if < or =5 years of age or erythromycin estolate if >5 years of age). Patients from 23 geographically diverse sites were evaluated for clinical outcomes and/or adverse events at Days 3 to 5, Days 15 to 19 and 4 to 6 weeks posttherapy. Microbiology (culture or polymerase chain reaction) was done at baseline and Days 15 to 19 for bacteria, Chlamydia pneumoniae and Mycoplasma pneumoniae. Serology for C. pneumoniae and M. pneumoniae was done at baseline and 4 to 6 weeks posttherapy. RESULTS: Of 456 patients enrolled during 17 consecutive months, 420 were evaluable. Clinical success at Study Days 15 to 19 was 94.6% in the azithromycin group and 96.2% in the comparative treatment group (P = 0.735) and at 4 to 6 weeks posttherapy 90.6 and 87.1%, respectively (P = 0.330). Evidence of infection was identified in 46% of 420 evaluable patients (1.9% bacteria, 29.5% M. pneumoniae and 15% C. pneumoniae). Microbiologic eradication was 81% for C. pneumoniae and 100% for M. pneumoniae in the azithromycin group vs. 100 and 57%, respectively, in the comparator group. Treatment-related adverse events occurred in 11.3% of the azithromycin group and 31% in the comparator group (P < 0.05). CONCLUSION: Azithromycin used once daily for 5 days produced a satisfactory therapeutic outcome similar to those of amoxicillin/clavulanate or erythromycin given three times a day for 10 days for treatment of community-acquired pneumonia. Azithromycin had significantly fewer side effects than comparator drugs.

Adolescent↗
PubMed1998

Nature vs nurture: are leaders born or made? A behavior genetic investigation of leadership style.

With the recent resurgence in popularity of trait theories of leadership, it is timely to consider the genetic determination of the multiple factors comprising the leadership construct. Individual differences in personality traits have been found to be moderately to highly heritable, and so it follows that if there are reliable personality trait differences between leaders and non-leaders, then there may be a heritable component to these individual differences. Despite this connection between leadership and personality traits, however, there are no studies of the genetic basis of leadership using modern behavior genetic methodology. The present study proposes to address the lack of research in this area by examining the heritability of leadership style, as measured by self-report psychometric inventories. The Multifactor Leadership Questionnaire (MLQ), the Leadership Ability Evaluation, and the Adjective Checklist were completed by 247 adult twin pairs (183 monozygotic and 64 same-sex dizygotic). Results indicated that most of the leadership dimensions examined in this study are heritable, as are two higher level factors (resembling transactional and transformational leadership) derived from an obliquely rotated principal components factors analysis of the MLQ. Univariate analyses suggested that 48% of the variance in transactional leadership may be explained by additive heritability, and 59% of the variance in transformational leadership may be explained by non-additive (dominance) heritability. Multivariate analyses indicated that most of the variables studied shared substantial genetic covariance, suggesting a large overlap in the underlying genes responsible for the leadership dimensions.

Adult↗