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Biomedical subjects

A Schwartz

Publications and source records attributed to A Schwartz.

At least 19 recordsLinked to original sources
PubMed2006

An audit of imaging test utilization for the management of lymphoma in an oncology hospital: implications for resource planning?

The purpose of this study was to assist with resource planning by examining the pattern of physician utilization of imaging procedures for lymphoma patients in a dedicated oncology hospital. The proportion of imaging tests ordered for routine follow up with no specific clinical indication was quantified, with specific attention to CT scans. A 3-month audit was performed. The reasons for ordering all imaging procedures (X-rays, CT scans, ultrasound, nuclear scan and MRI) were determined through a retrospective chart review. 411 lymphoma patients had 686 assessments (sets of imaging tests) and 981 procedures (individual imaging tests). Most procedures were CT scans (52%) and chest radiographs (30%). The most common reasons for ordering imaging were assessing response (23%), and investigating new symptoms (19%). Routine follow up constituted 21% of the assessments (142/686), and of these, 82% were chest radiographs (116/142), while 24% (34/142) were CT scans. With analysis restricted to CT scans (296 assessments in 248 patients), the most common reason for ordering CT scans were response evaluation (40%), and suspicion of recurrence and/or new symptom (23%). Follow-up CT scans done with no clinical indication comprised 8% (25/296) of all CT assessments. Staging CT scans were under-represented at 6% of all assessments. Imaging with CT scans for follow up of asymptomatic patients is infrequent. However, scans done for staging new lymphoma patients were unexpectedly low in frequency, due to scans done elsewhere prior to referral. This analysis uncovered utilization patterns, helped resource planning and provided data to reduce unnecessary imaging procedures.

Adolescent↗
PubMed2004

Quantification of EGFP expression on Molt-4 T cells using calibration standards.

BACKGROUND: Enhanced green fluorescent protein (EGFP) is used extensively to assess gene expression on cells; however, quantification of this expression by flow cytometry has been limited by the unavailability of calibration standards. Thus, we characterized the response of an experimental set of EGFP calibration standards to environmental changes and then quantitate the expression of EGFP, in molecules of equivalent soluble fluorochrome (MESF) units, of a transfected Molt-4 T cell line by flow cytometry. METHODS: Characterization of the EGFP standards: EGFP standards were equilibrated in suspension solutions having a pH range of 5.0-9.0, temperatures of 37-80 degrees C, and osmolalities of 100-600 mOsm/kg. Quantification of EGFP on cells: For transfections, Molt-4 T cells were incubated with two different concentrations (0.2 microg and 0.4 microg) of pEGFP-N2 vector and the EGFP expression was quantified after 48 h by flow cytometry using the EGFP standards and by the cytofluor technique using a standard curve of known EGFP solutions. RESULTS: The fluorescence intensity of the EGFP standards increased from pH 5.0 to 9.0 and remained relatively constant from 37 degrees C to 65 degrees C, and from 100 to 600 mOsm/kg. After transfection, the expression of the populations with high and low EGFP expression averaged 8,098 +/- 584 MESF and 3,808 +/- 375 MESF respectively. No significant differences were observed after comparing the MESF values obtained by flow cytometry and the values obtained by Cytofluor technique (high: 8,791 +/- 492 MESF; low: 4,082 +/- 398 MESF). CONCLUSIONS: Our data demonstrate the feasibility of using calibration standards to quantify EGFP expression on cells. Our results emphasize the importance of monitoring the effects of environmental changes in the fluorescence intensity of both standards and samples when quantifying the expression of EGFP on living cells.

Calibration↗
PubMed2004

Methodological standardization for a multi-institutional in vivo trial of localized 31P MR spectroscopy in human cancer research. In vitro and normal volunteer studies.

A multi-institutional group has been created to demonstrate the utility of in vivo 31P magnetic resonance spectroscopy (31P-MRS) to study human cancers in vivo. This review is concerned with the novel problems concerning quality control in this large multinational trial of 31P MRS. Our results show that the careful and systematic performance of the quality control tests depicted here (standardized dual 1H/31P tuned radiofrequency probe, quality control procedures, routine use of 1H irradiation while acquiring 31P MR signals) has ensured comparable results between the different institutions. In studies made in vitro, the root-mean-square error was 3.6 %, and in muscle of healthy volunteers in vivo the coefficients of variance for the ratios phosphocreatine/nucleotide-triphosphates, phosphocreatine/noise and nucleotide-triphosphate/noise were 12.2, 7.0 and 10.8 %, respectively. The standardization of the acquisition protocol for in vivo-localized 31P MR spectroscopy across the different institutions has resulted in comparable in vivo data, decreasing the possible problems related to a research study carried out under a multi-institutional setting.

Biomarkers, Tumor↗
PubMed2004

Prevalence of Streptococcus pneumoniae and Staphylococcus aureus nasopharyngeal colonization in healthy children in the United States.

This study documents the colonization of Staphylococcus aureus (SA), Streptococcus pneumoniae (SP) and specific resistant forms of these organisms among healthy children and identifies risk factors associated with these pathogens. Prospective point prevalence survey of nasopharyngeal specimens were obtained from 291 healthy children seeking routine well-child care at a university-based ambulatory paediatric clinic in a large urban city in the United States. A total of 291 children less than 5 years were enrolled during a 1-year period. Fifty-four (18.6%) were colonized with SA and 47 (16.2%) were colonized with SP. Among the 54 SA isolates, five (9.2%) were methicillin resistant (MRSA) and among the SP isolates, three (6.4%) were intermediate to penicillin (DRSP). Eighty per cent of all children enrolled reported no underlying medical condition. Care outside their home was more common among colonized (40.8%, 40/98) than non-colonized children (25.4%, 49/193), P=0.007. Healthy children from households of four or more people were also more likely to be colonized. The colonization rate of SA and SP among healthy children is consistent with what has been reported in the literature. The prevalence of MRSA and DRSP among healthy children colonized with SA or SP is low in this population of children attending a university-based ambulatory care centre in the United States.

Age Factors↗
PubMed2004

The anaesthetic management of patients with congenital insensitivity to pain with anhidrosis.

BACKGROUND: Congenital insensitivity to pain with anhidrosis (CIPA, or hereditary sensory and autonomic neuropathy type IV) is a rare, autosomal recessive disease, related to a mutation in the TrkA gene, characterized by inability to sweat, insensitivity to pain and recurrent episodes of hyperpyrexia. There are two Bedouin tribes in Israel with different mutations of the TrkA gene: one in the southern region and the other in the northern region. The Soroka University Medical Center is the referral centre for the entire southern region of Israel. One in 4500 anaesthesia cases involves a patient with CIPA. METHODS: We reviewed 40 anaesthesia records of 20 patients with CIPA for anaesthetic technique and incidence of side-effects. RESULTS: Sixteen patients developed complications in the immediate perioperative period: mild hypothermia in one patient and cardiovascular events in 15 others with one case of cardiac arrest. These complications were unrelated to the anaesthetic drug administered. There were no events of hyperthermia or postoperative nausea. CONCLUSIONS: Cardiovascular complications following anaesthesia are common in patients with the southern Israel variant of CIPA. Hyperthermia, previously recognized as a major concern in patients with congenital insensitivity to pain with anhydrous, was not seen in our patients. We conclude that cardiovascular involvement is frequently encountered in CIPA patients following anaesthesia and is the major concern in their anaesthetic management.

Adolescent↗
PubMed2004

[Long-term hemodynamic compromise in internal carotid artery dissection: quantitative blood volume flow evaluation using 2D Cine phase-contrast MR imaging].

PURPOSE: To use the magnetic resonance (MR) phase-contrast technique as a non-invasive method to determine blood volume flow in internal carotid artery (ICA) dissection, which has variable initial volume flow reduction and long term hemodynamic compromise. ICA dissection can lead to partial or complete recanalization or persistent occlusion, and strong clinical motivation exists for reliable assessment of the blood flow, in particular blood volume flow, in the carotid artery circulation after ICA dissection. MATERIALS AND METHODS: Blood volume flow in the carotid artery circulation was quantified in 28 patients with unilateral ICA dissection and 20 age-matched normal controls. Blood volume flow was measured in the ICAs and the common carotid arteries (CCAs) using 2D cine phase-contrast MR imaging. Final measurements were performed until after at least 6 months the hemodynamic compromise showed no changes by ultrasound and MRA. RESULTS: In long term follow up, 11/28 patients demonstrated remaining vessel occlusion, 10/28 partial and 7/28 complete recanalizations. Patients with ICA occlusion showed a significant contralateral volume flow increase (mean 56 %, p < 0.001) in comparison to normal controls. Patients with partial recanalization demonstrated volume flow rates between 24 ml/min and 188 ml/min in the dissected ICA and a less but significant (p < 0.001) increase in the contralateral volume flow. In patients with complete recanalization, normal volume flow conditions were found for both ICAs and CCAs. CONCLUSION: In ICA dissection, quantitative volume flow determination using 2D cine phase-contrast MR imaging is helpful in the initial assessment and long term follow-up of hemodynamic compromise. ICA dissection demonstrated a partial or complete recanalization in nearly (2/3) of the investigated patients and a persisting vessel occlusion in little more than (1/3). Compensatory contralateral increase in volume flow was found.

Adult↗
PubMed2004

The cost of immunity in the yellow fever mosquito, Aedes aegypti depends on immune activation.

Although host immunity offers the obvious benefit of reducing parasite infection, it is often traded-off with other fitness components. We investigated whether the cost of an immune response in the yellow fever mosquito, Aedes aegypti, is modulated by the antigen that activates the melanization immune response. Thus, one of three different novel antigens were injected into the mosquito's thorax--either a glass bead, a negatively charged (C-25) Sephadex bead, or a neutral (G-25) Sephadex bead--and fecundity and bead melanization were observed. Glass beads are immunologically inert and were therefore used as an inoculation control. The fecundity of mosquitoes inoculated with these beads did not differ from the fecundity of mosquitoes that did not melanize negatively charged or neutral beads. The ability of A. aegypti to melanize negatively charged Sephadex beads was associated with reduced fecundity, showing a clear cost of immunity. In contrast, melanization of the neutral beads was quite strong but had no effect on fecundity. Thus, the cost of what appeared to be the same immune response--melanization of a bead--depended on the type of bead that stimulated the immune system. Such differences might help to explain variation of immune efficacy against different parasites in natural populations.

Aedes↗
PubMed2002

[Glioblastoma multiforme as a manifestation of Turcot syndrome].

Turcot's syndrome, clinically characterized by the coincident occurrence of primary tumors of the colon and the central nervous system, can genetically be divided into two syndromes: familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon carcinoma (HNPCC). In the present case, a 60-year-old patient with glioblastoma multiforme and a history of hereditary malignomas is described as an example of a HNPCC-associated Turcot's syndrome. New molecular biological methods and results give deeper insight into clinical syndromes, and the better understanding improves diagnostics, therapy, and outcome estimations, even in rare diseases. In the present case, a new germinal mutation could be identified.

Adaptor Proteins, Signal Transducing↗
PubMed2002

Practical importance of neuroprotection in Parkinson's disease.

Consensus could be reached that there is overwhelming evidence of preclinical neuroprotection. However, the evidence of neuroprotection/neurorescue under clinical conditions is limited. Lessons from clinical trials designed to show neuroprotection (selegiline, amantadine, dopamine agonists) demonstrate that with the drugs available neuroprotection/neurorescue has to start as early as possible. A PET-controlled clinical trial with ropinirole shows that there seems to be a good chance for neuroprotection in the early phase of Parkinson's disease in patients treated from the very beginning of the disease while there is no such benefit in patients with a late start of a neuroprotective therapeutic strategy. Also long-term clinical neuroprotection cannot be reached. Complicating factors to demonstrate clinical neuroprotection are discussed.

Amantadine↗
PubMed2001

Elevated plasma tissue plasminogen activator and anti-THP-1 antibodies are independently associated with decreased graft survival in cardiac transplant recipients.

Hemostatic and immunologic factors have been implicated in future cardiac events in patients with coronary artery disease. The role of these factors and their interaction is less established in cardiac transplant recipients. We sought to characterize the role of these factors in these patients. Cardiac transplant patients who presented for surveillance coronary angiography and/or endomyocardial biopsy were eligible for enrollment. Ninety-nine consecutive patients were enrolled. Plasma levels of tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor-1, von Willebrand factor, fibrin D-dimer, and anti-t-PA antibody were determined by enzyme-linked immunosorbent assays. Anti-THP-1 cell antibodies directed against a monocytic leukemia cell line were detected by incubating patient plasma with THP-1 cells. Bound antibody was detected using goat peroxidase-labeled immunoglobulin G directed against human immunoglobulins. Lipids were measured by enzymatic methods. Multivariate analysis identified the presence of anti-THP-1 cell antibodies (risk ratio 4.41, p = 0.002), t-PA antigen (risk ratio 1.10, p = 0.033), donor age 20 to 26 years (risk ratio 8.83, p = 0.042), and donor age >36 years (risk ratio 15.53, p = 0.009) as predictors of allograft failure. Altered hemostatic function, as demonstrated by elevated plasma t-PA antigen levels, is predictive of subsequent allograft failure in cardiac transplant recipients. In addition, the presence of anti-THP-1 cell antibodies in these patients is predictive of allograft failure.

Chi-Square Distribution↗
PubMed2001

Assessment of the usefulness of a diagnostic test: a survey of patient preference for diagnostic techniques in the evaluation of intestinal inflammation.

BACKGROUND: In order to assess the usefulness of radiolabeled white cell scanning in the diagnosis of intestinal inflammation, subjects were asked to rank several dimensions of preference for white cell scanning in relation to other diagnostic tests. Two groups were surveyed: one known to have inflammatory bowel disease and the second not familiar in most cases with the tests. Subjects were asked to rank preference for each of seven tests: radiolabeled white cell scan, colonoscopy, barium enema, sigmoidoscopy, enteroclysis, stool analysis and laparotomy for the diagnosis of IBD and impressions of discomfort, embarrassment, inconvenience and danger related to each test. Mean rank scores were calculated, test ranks compared within groups and significance determined by the Wilcoxon rank test. RESULTS: Significant differences were seen in overall preference for white cell scan over barium enema and colonoscopy (p < 0.01) in both survey groups. Perceived discomfort and embarrassment demonstrated similar rankings. CONCLUSION: This patient preference combined with the reported accuracy of white cell scanning further establishes the usefulness of this means of IBD diagnosis.

Adolescent↗
PubMed2001

Functional disorders of the sympathetic nervous system in mice lacking the alpha 1B subunit (Cav 2.2) of N-type calcium channels.

N-type voltage-dependent Ca(2+) channels (VDCCs), predominantly localized in the nervous system, have been considered to play an essential role in a variety of neuronal functions, including neurotransmitter release at sympathetic nerve terminals. As a direct approach to elucidating the physiological significance of N-type VDCCs, we have generated mice genetically deficient in the alpha(1B) subunit (Ca(v) 2.2). The alpha(1B)-deficient null mice, surprisingly, have a normal life span and are free from apparent behavioral defects. A complete and selective elimination of N-type currents, sensitive to omega-conotoxin GVIA, was observed without significant changes in the activity of other VDCC types in neuronal preparations of mutant mice. The baroreflex response, mediated by the sympathetic nervous system, was markedly reduced after bilateral carotid occlusion. In isolated left atria prepared from N-type-deficient mice, the positive inotropic responses to electrical sympathetic neuronal stimulation were dramatically decreased compared with those of normal mice. In contrast, parasympathetic nervous activity in the mutant mice was nearly identical to that of wild-type mice. Interestingly, the mutant mice showed sustained elevation of heart rate and blood pressure. These results provide direct evidence that N-type VDCCs are indispensable for the function of the sympathetic nervous system in circulatory regulation and indicate that N-type VDCC-deficient mice will be a useful model for studying disorders attributable to sympathetic nerve dysfunction.

Animals↗
PubMed2001

Reduction of [Ca(2+)](i) restores uncoupled beta-adrenergic signaling in isolated perfused transgenic mouse hearts.

The effects of alterations in calcium in the perfusion media were studied on ss-adrenergic coupling in isolated hearts from 3 different transgenic mice: cardiac-specific overexpressed alpha(1) subunit of L-type calcium channel, overexpressed Galpha(q), and phospholamban knockout. Isolated hearts from all 3 models, when studied at [Ca(2+)] of 2 mmol/L in the perfusate, showed the usual blunted or no response to ss-adrenergic stimulation. Lowering [Ca(2+)] to 0.75 to 1.5 mmol/L unloaded the hearts of calcium and restored to nearly normal the responsiveness to ss-agonist stimulation.

Animals↗
PubMed2001

Excess incidence of squamous cell esophageal cancer among US Black men: role of social class and other risk factors.

Data from a population-based case-control study were used to evaluate the relation between social class factors and squamous cell esophageal cancer and the extent to which alcohol, tobacco, diet, and low income contribute to the higher incidence among Black men than among White men in the United States. A total of 347 male cases (119 White, 228 Black) and 1,354 male controls (743 White, 611 Black) were selected from three US geographic areas (Atlanta, Georgia, Detroit, Michigan, and New Jersey). Cases were residents of the study areas aged 30-79 years who had been diagnosed with histologically confirmed esophageal cancer between 1986 and 1989. The adjusted odds ratios for subjects with annual incomes less than $10,000 versus incomes of $25,000 or more were 4.3 (95% confidence interval: 2.1, 8.7) for Whites and 8.0 (95% confidence interval: 4.3, 15.0) for Blacks. The combination of all four major risk factors-low income, moderate/heavy alcohol intake, tobacco use, and infrequent consumption of raw fruits and vegetables-accounted for almost all of the squamous cell esophageal cancers in Whites (98%) and Blacks (99%) and for 99% of the excess incidence among Black men. Thus, lifestyle modifications, especially a lowered intake of alcoholic beverages, would markedly decrease the incidence of squamous cell esophageal cancer in both racial groups and would narrow the racial disparity in risk. Further studies on the determinants of social class may help to identify a new set of exposures for this tumor that are amenable to intervention.

Adult↗
PubMed2001

A Ca(2+)-dependent transgenic model of cardiac hypertrophy: A role for protein kinase Calpha.

BACKGROUND: Calcium imbalances have been implicated as an underlying mechanism of human cardiac dysfunction. The voltage-dependent calcium channel plays a critical role in calcium regulation in the heart. Thus, aberrant calcium signaling arising from this channel could initiate the calcium imbalances observed in heart failure. In the present study, we used a transgenic mouse with an increased number of L-type calcium channels to identify the role of an increased, sustained ingress of calcium as an initiator of hypertrophy. METHODS AND RESULTS: Whole-heart histology and electrophysiology in isolated cardiomyocytes identified calcium-channel overexpression in the hearts of transgenic mice. Calcium-channel density was increased in 2-, 4-, and 8-month-old transgenic cardiomyocytes. Ventricular fibrosis, damage, and remodeling became more pronounced as the transgenic mice aged. Apoptosis was also present in transgenic hearts at 8 months of age. Increased protein kinase Calpha activation was elevated before the development of hypertrophy and failure. CONCLUSIONS: Transgenic mice developed hypertrophy and severe cardiomyopathy as a function of age, thus confirming that changes in channel density are sufficient to induce disease. The small, sustained increase in the ingress of Ca(2+) through the calcium channel elevated protein kinase Calpha before the development of hypertrophy, suggesting that protein kinase Calpha plays an important role in triggering hypertrophy.

Aging↗
PubMed2001

Elevated plasma levels of interleukin-2 and soluble IL-2 receptor in ischemic heart disease.

BACKGROUND: T-lymphocytes are present in significant numbers in the atherosclerotic plaque, but their role in the progression and pathogenesis of coronary syndromes remains poorly understood. HYPOTHESIS: We sought to determine the relationship between T-lymphocyte activation and ischemic heart disease by measuring plasma levels of cytokines related to T-lymphocyte function in patients with stable and unstable angina. METHODS: Plasma levels of interleukin-2 (IL-2) and soluble IL-2 receptor (sIL-2R) were measured in 105 patients: 66 with stable angina, 24 with unstable angina, and 15 healthy controls. Patients who presented to the cardiac catheterization laboratory with unstable or stable anginal syndromes for coronary angiography or percutaneous coronary intervention enrolled in the study. RESULTS: Mean levels of IL-2 were significantly higher in patients with stable angina than in those with unstable angina. The differences between stable angina and control groups, or between unstable angina and control groups, were not statistically significant. Mean levels of slL-2R were significantly higher in patients with stable angina than in either patients with unstable angina or control patients. CONCLUSIONS: Levels of IL-2 and sIL-2 receptor are significantly elevated in patients with stable angina, but not in patients with unstable angina. The contribution of T-lymphocytes to the development of both stable and unstable angina requires further investigation.

Adult↗
PubMed2001

Waldenström's macroglobulinemia associated with AA amyloidosis.

It is widely accepted that amyloidosis in Waldenström's macroglobulinemia (WM) is exclusively due to amyloid light-chain deposition. However, only a small number of previous reports have actually characterized the type of amyloid in WM. We now report the third patient with WM and amyloid A protein (AA) amyloidosis. This patient developed malabsorption, nephrotic syndrome, and orthostatic hypotension. AA was immunohistochemically demonstrated in the rectal biopsy. In conjunction with previous examples of AA amyloidosis, the present report raises the possibility that AA amyloidosis may also occur in WM patients.

Aged↗