Biomedical subjects
Publications and source records attributed to John Harvey.
The diagnosis and management of a 14-year-old girl with isolated traumatic transection of the prepylorus after a motor vehicle accident are presented. Abdominal computed tomography was useful in the diagnosis of pneumoperitoneum associated with hollow viscous injury. Rapid diagnosis and surgical repair of this unusual injury resulted in an uncomplicated recovery.
Gastrointestinal bleeding is a morbid complication of pancreaticoduodenectomy. Determining its etiology is often a daunting challenge in that both common and unusual mechanisms may be operative. Visceral artery pseudoaneurysms, although rare, must be considered in that minimally invasive means are available for effective therapy. Our recent experience with two cases highlights the importance for both general and vascular surgeons to be aware of the diagnostic and therapeutic role for early angiography and deployment of endovascular techniques to achieve a successful outcome.
Minimally invasive surgery has a role in planning the resection of malignant chest wall tumors in the pediatric population. We studied the role of thoracoscopy in both the diagnosis and definitive surgery of chest wall Ewing's sarcoma tumors.
Some children with relapsed or high-risk acute leukaemia have an improved outcome if they have an allogeneic stem cell transplant, preferably from a sibling or well-matched unrelated donor. However, some children do not have these options or there is an urgent need to proceed to transplant because of disease status. We have investigated the role of haploidentical family members as donors in 34 patients with acute leukaemia (median age 11 years, range 1-16 years). Patients were conditioned with cyclophosphamide and total body irradiation (14.4 Gy in eight fractions) and received T-cell depleted peripheral blood stem cell grafts with a median CD34 cell dose of 13.8 x 10(6)/kg (range 4.2-35.1) and 0.7 x 10(4) CD3-positive cells/kg. The actuarial survival at 2 years was 26% (13-41%, 95% CI). Eight patients have survived disease-free with a median follow up of 62 months. They have good performance status and a median lymphocyte count of 1.8 x 10(9)/l. Relapse (14 patients) and adenoviral (six patients) or fungal infections (four patients) were the major causes of death. Haploidentical stem cell transplantation can produce medium term disease-free survival in a proportion of children with high-risk or relapsed acute leukaemia. None of the nine patients with acute myeloid leukaemia not in remission have survived.
BACKGROUND: Previous studies have suggested that autologous skeletal myoblast transplantation (ASMT) improves left ventricular (LV) function in small animals after myocardial infarction. We tested the effects of ASMT on hemodynamics, LV function and remodeling in coronary microembolization-induced chronic heart failure (CHF) in conscious dogs. METHODS: Nineteen dogs were continuously instrumented with LV pressure sensors and mid-myocardial sonomicrometry crystals for dP/dt(max) and LV volume determination. Each dog underwent baseline assessment in a conscious state. CHF (20% to 30% reduction in dP/dt(max) and LV end-diastolic pressure >16 mm Hg) was created by daily coronary microembolizations via a continuously implanted coronary catheter. Skeletal muscle biopsy was performed and myoblasts were isolated and expanded. Then 2.7 x 10(8) to 8.3 x 10(8) myoblasts were injected into the infarcted region of 11 dogs after establishment of CHF. Saline injection (sham) was performed in 8 control dogs. Animals were evaluated every 2 weeks for up to 10 weeks. Global ejection fraction was determined by echocardiography. The end-systolic pressure-end-systolic volume relationship (ESPVR) was analyzed by the Sonomicrometic system. RESULTS: Compared with saline injection, ASMT significantly increased dP/dt(max) (105 +/- 9% vs 97 +/- 7%, values were expressed as percentage change from baseline CHF, p = 0.013) and ejection fraction (46 +/- 3% vs 40 +/- 2%, p = 0.034) at 10 weeks after myoblast transplantation. There was a significant leftward and upward shift of the ESPVR back toward normal at 10 weeks after myoblast transplantation (p = 0.034). Three animals labeled with BrdU myoblasts showed no histologic evidence of viable engraftment. CONCLUSIONS: ASMT provided mild improvements in hemodynamics and LV function and reduced LV remodeling in conscious dogs with CHF.
Genetic testing in a clinical diagnostic environment must be subject to rigorous quality control procedures, in order to ensure consistency and accuracy of results. Denaturing high performance liquid chromatography (DHPLC) has become a standard prescreening tool for mutation detection, offering very high efficiency and sensitivity of detection. Despite the relatively simple software-assisted assay setup, DHPLC is a complex assay, and quality control is reliant on ensuring optimal instrument performance, excellent assay design and validation, and sufficient user training and proficiency to interpret results. We describe here a unique collaborative effort by a group of diagnostic clinical genetics laboratories with DHPLC expertise who, together with the manufacturer of one of the most widely used DHPLC platforms, have generated standard operating procedures (SOPs) for instrument operation and maintenance, and for mutation detection by DHPLC. We also describe the validation of a disease-specific SOP for DHPLC assisted mutation screening of the MECP2 gene associated with Rett syndrome. The proposed SOP was validated, and used independently in two laboratories to introduce MECP2 testing. In addition, we provide empirically derived normal ranges for the WAVE System Mutation Standards, which are essential for optimal instrument performance. This effort was initiated to try to standardize DHPLC-based mutation screening procedures across laboratories, and so increase the overall quality of this testing method. This endeavor will thus save each laboratory from having to generate SOPs on their own, which is a lengthy and laborious task. In this respect, we define "generic" SOPs as procedures that are easily adaptable to the individual laboratories' quality systems.
Explore the source record for details and available documents.
OBJECTIVE: This study examined whether the situational factors that contribute to severe grief in the general population predicted the severity of grief in a sample of persons who had diagnoses of serious mental illness. METHOD: Research participants who had a diagnosis of a serious mental illness and who reported the death of a close friend or family member during a five-year service evaluation project were asked to detail the circumstances that surrounded the death and to rate how the death affected their lives. Key research measures included the self-rated measurement of the impact of the death, the self-rated measurement of the duration of the reported grief, and scores on a psychiatric symptom assessment in the six months after the death. A regression analysis tested the cumulative count of four situational factors-residing with the close friend or family member at the time of the death, the suddenness of the death, having low social support, and having concurrent stressors-as a predictor of severe and prolonged grief. RESULTS: In the sample of 148 individuals with serious mental illness, 33 (22 percent) reported the death of a close friend or family member as a significant life event that resulted in relatively acute and brief grief (15 individuals, or 10 percent) or severe and prolonged grief (18 individuals, or 12 percent). The regression analysis confirmed that the more situational factors that occurred at the time of the death, the more severe the grief reaction was, irrespective of psychiatric symptomatology. CONCLUSIONS: Mental health services for persons with serious mental illness should begin to incorporate preparation for parental death and bereavement counseling as essential services, and such interventions should approach bereavement as a normal rather than a pathological response to interpersonal loss.
Explore the source record for details and available documents.
DNA polymerase (pol) beta is a two-domain DNA repair enzyme that undergoes structural transitions upon binding substrates. Crystallographic structures indicate that these transitions include movement of the amino-terminal 8-kDa lyase domain relative to the 31-kDa polymerase domain. Additionally, a polymerase subdomain moves toward the nucleotide-binding pocket after nucleotide binding, resulting in critical contacts between alpha-helix N and the nascent base pair. Kinetic and structural characterization of pol beta has suggested that these conformational changes participate in stabilizing the ternary enzyme-substrate complex facilitating chemistry. To probe the microenvironment and dynamics of both the lyase domain and alpha-helix N in the polymerase domain, the single native tryptophan (Trp-325) of wild-type enzyme was replaced with alanine, and tryptophan was strategically substituted for residues in the lyase domain (F25W/W325A) or near the end of alpha-helix N (L287W/W325A). Influences of substrate on the fluorescence anisotropy decay of these single tryptophan forms of pol beta were determined. The results revealed that the segmental motion of alpha-helix N was rapid ( approximately 1 ns) and far more rapid than the step that limits chemistry. Binding of Mg(2+) and/or gapped DNA did not cause a noticeable change in the rotational correlation time or angular amplitude of tryptophan in alpha-helix N. More important, binding of a correct nucleotide significantly limited the angular range of the nanosecond motion within alpha-helix N. In contrast, the segmental motion of the 8-kDa domain was "frozen" upon DNA binding alone, and this restriction did not increase further upon nucleotide binding. The dynamics of alpha-helix N are discussed from the perspective of the "open" to "closed" conformational change of pol beta deduced from crystallography, and the results are more generally discussed in the context of reaction cycle-regulated flexibility for proteins acting as molecular motors.