Biomedical subjects

C Schmitt

Publications and source records attributed to C Schmitt.

At least 145 records · Page 8Linked to original sources

PubMed1999

The nine C-terminal residues of the grapevine fanleaf nepovirus movement protein are critical for systemic virus spread.

The grapevine fanleaf virus (GFLV) RNA2-encoded polyprotein P2 is proteolytically cleaved by the RNA1-encoded proteinase to yield protein 2A, 2B(MP) movement protein and 2C(CP) coat protein. To further investigate the role of the 2B(MP) and 2C(CP) proteins in virus movement, RNA2 was engineered by alternatively replacing the GFLV 2B(MP) and 2C(CP) genes with their counterparts from the closely related Arabis mosaic virus (ArMV). Transcripts of all chimeric RNA2s were able to replicate in Chenopodium quinoa protoplasts and form tubules in tobacco BY-2 protoplasts in the presence of the infectious transcript of GFLV RNA1. Virus particles were produced when the GFLV 2C(CP) gene was replaced with its ArMV counterpart, but systemic virus spread did not occur in C. quinoa plants. In addition, chimeric RNA2 containing the complete ArMV 2B(MP) gene was neither encapsidated nor infectious on plants, probably because polyprotein P2 was incompletely processed. However, chimeric RNA2 encoding ArMV 2B(MP), in which the nine C-terminal residues were those of GFLV 2B(MP), formed virus particles and were infectious in the presence of GFLV but not ArMV 2C(CP). These results suggest that the nine C-terminal residues of 2B(MP) must be of the same virus origin as the proteinase for efficient proteolytic processing of polyprotein P2 and from the same virus origin as the 2C(CP) for systemic virus spread.

Amino Acid Sequence↗

PubMed1999

A prospective randomized comparison of endoscopic ultrasound- and computed tomography-guided celiac plexus block for managing chronic pancreatitis pain.

OBJECTIVE: Computed tomography (CT)-guided celiac plexus neurolysis has been used for controlling the chronic abdominal pain associated with intra-abdominal malignancy and chronic pancreatitis. Endoscopic ultrasound (EUS)-guided celiac plexus neurolysis has been reported to have some success in controlling pain from pancreatic cancer. The aim of this study is to assess the efficacy of EUS-guided celiac plexus block versus CT-guided celiac plexus block for controlling the chronic abdominal pain associated with chronic pancreatitis. METHODS: Patients enrolled were randomly assigned to EUS-guided or CT-guided celiac plexus block. Pain scores were determined pre- and postceliac block for both techniques. Follow-up was obtained by a nurse at 1 day post-block, then weekly thereafter for 24 wk. Patients also rated overall experience with these procedures. The EUS celiac block was performed with a 22-gauge sterile needle inserted into the celiac region with guidance of real-time linear array endosonography followed by injection of 10 ml of bupivacaine (0.75%) and 3 ml (40 mg) of triamcinolone on both sides of the celiac area. RESULTS: Twenty-two consecutive patients (10 men, 12 women), were ultimately enrolled in this study between 7/1/95 and 12/30/95; four patients were excluded for protocol violations. We performed EUS-guided celiac block in 10 patients and CT-guided celiac block in eight. A significant improvement in pain scores with reduction in pain medication usage occurred in 50% (five of 10) of patients having the EUS block. The mean postprocedure follow-up was 15 weeks (range: 8-24 wk). Persistent benefit was experienced by 40% of patients at 8 wk and by 30% at 24 wk. In the patients with CT block, however, only 25% (two of eight) had relief. The mean follow-up was 4 wk (range: 2-6 wk). Only 12% (one of eight) had some relief at 12 wk of follow-up. There were no complications. EUS-guided celiac block was the preferred technique among patients who experienced both techniques. A cost comparison between both celiac block techniques shows EUS to be less costly than CT. CONCLUSIONS: EUS-guided celiac block provided more persistent pain relief than CT-guided block and was the preferred technique among the subjects studied. EUS-guided celiac block appears to be a safe, effective, and less costly method for controlling the abdominal pain that can accompany chronic pancreatitis in some patients.

Abdominal Pain↗

PubMed1999

Barrett's esophagus: a new look at surveillance based on emerging estimates of cancer risk.

OBJECTIVE: Surveillance of Barrett's patients is recommended, to detect dysplasia and early cancer. The reported risk for developing cancer varies substantially, however. Our previous analysis used an average cancer incidence of 1/75 patient-years (PY). Recent reports suggest that the risk may range from 1/251 to 1/208 PY in combined series of patients with long segment Barrett's esophagus (LSBE, >3 cm), and short segment Barrett's esophagus (SSBE), and up to 1% annually in patients with SSBE. Our goal was to consider these new estimates of cancer risk in a cost-utility analysis of surveillance of patients with Barrett's esophagus. METHODS: Using our previously published model, we incorporated an average of the recent estimates of cancer risk (0.4% annually, 1/227 PY), and our primary data on quality of life after esophagectomy. We included actual variable (direct) costs and used a discount rate of 5%. From the perspective of an HMO, the model evaluates surveillance every 1-5 yr and no surveillance, with esophagectomy performed if high grade dysplasia is diagnosed, and calculates the incremental cost-utility ratios for each strategy. RESULTS: The results suggest that, at our baseline, annual cancer risk surveillance every 5 yr is the only viable strategy. More frequent surveillance costs more and yields a lower life expectancy. The incremental cost-utility ratio for surveillance every 5 yr is $98,000/quality-adjusted life year (QALY) gained, comparable to the incremental cost-effectiveness ratios of accepted practices (heart transplantation and screening for tuberculosis in selected populations, $160,000/LY gained and $216,000/LY gained, respectively). CONCLUSIONS: Surveillance of Barrett's patients should extend life, with incremental cost-utility ratios that compare favorably with some accepted medical practices. Policy makers can compare the cost of surveillance to that of other accepted practices to determine their willingness to fund surveillance.

Adenocarcinoma↗

PubMed1999

Outcome of radiation-related osteosarcoma after treatment of childhood and adolescent cancer: a study of 23 cases.

PURPOSE: We analyzed the clinical features and outcome of patients with radiation-associated osteosarcoma treated during the era of contemporary chemotherapy. PATIENTS AND METHODS: The characteristics and outcome of 23 patients (17 males and six females) treated during childhood or adolescence for a solid tumor who later developed osteosarcomas within the radiation field between 1981 and 1996 were reviewed. RESULTS: The median dose of radiation delivered to the first cancer was 47 Gy. Nineteen patients also received chemotherapy. The median time between radiotherapy and the diagnosis of secondary osteosarcoma was 8 years. Histologic slide review showed conventional central osteosarcoma with various differentiation patterns in 21 cases, together with one case of high-grade surface osteosarcoma and one of periosteal osteosarcoma. The sites of involvement were the craniofacial bones in six cases, the first cervical vertebra in one, the girdle bones in seven, and the extremities of long bones in nine. Three patients had metastatic disease at the diagnosis of osteosarcoma. Palliative therapy was administered to seven patients. The aim of treatment was curative for 16 patients, two of whom underwent amputation without further therapy. Intensive chemotherapy regimens were administered to 14 patients before and/or after surgery. Fifteen patients achieved complete surgical remission. Twelve patients were alive and disease-free at a median follow-up duration of 7.5 years. Overall and event-free survivals at 8 years were 50% and 41%, respectively. CONCLUSION: Patients with radiation-related osteosarcoma and resectable lesions can be cured with surgery and intensive preoperative and postoperative chemotherapy.

Adolescent↗

PubMed1999

[Malignant non-seminomatous germinal tumors of the ovary. Experience of the French Society of Pediatric Oncology. 64 cases].

Ovary seminomatous malignant germ cell tumours are a particular histopathologica entity. The presence of yolk salk tumor or choriocarcinoma is respectively correlated with elevation of alpha FP or beta hCG. This markers elevation permits to assess diagnosis, appreciate response to treatment, and detect relapses. The study of 64 patients registered in two successive S.F.O.P. protocols (TGM 85-TGM 90) precise indications of surgery, platin-based chemotherapy and results. Malignant non seminomatous germ cell tumors are separated in not secreting pure immature teratoma and secreting malignant germ cell tumours. Surgery is essential for treatment of not secreting pure immature teratoma. Secreting germ cell tumors are very chemosensitive and surgery must be as conservative as possible in all cases even metastatic tumour or relapse. If markers are normalized second-look surgery of secreting malignant germ cell tumours is only necessary in case of evident residual tumour. However in case of initial chemotherapy, resection of a pathological ovary is always performed at the end of treatment. These tumours have a good prognosis: 5-years overall survival and disease-free survival are 85%.

Adolescent↗

PubMed1998

Effect of glycoprotein IIb/IIIa receptor blockade on recovery of coronary flow and left ventricular function after the placement of coronary-artery stents in acute myocardial infarction.

BACKGROUND: Apart from its established effects on vessel patency after percutaneous coronary revascularization, glycoprotein IIb/IIIa receptor blockade by abciximab may improve myocardial perfusion by inhibition of the interaction of platelets and platelet aggregates with the microvasculature. We investigated the effect of abciximab with stent placement in acute myocardial infarction. METHODS AND RESULTS: In a prospective randomized trial, patients undergoing stenting in acute myocardial infarction within 48 hours after onset of symptoms were randomly assigned to receive either standard-dose heparin or abciximab plus low-dose heparin. Immediately after the procedure and at 14-day angiographic follow-up, we assessed flow velocity in the recanalized vessel with the Doppler wire and regional wall motion by the centerline method. End points were changes in papaverine-induced peak flow velocities and in wall motion indices. We assigned 98 patients to standard heparin and 102 to abciximab. We obtained 152 paired flow measurements and 151 paired left ventricular function studies. Residual stenoses of the treated lesions did not differ between the 2 groups. Improvement of peak flow velocity (mean [95% CI]: 18.1 cm/s [13.6 to 22.6 cm/s], n=80, versus 10.4 cm/s [5.4 to 15.4 cm/s], n=72, P=0.024) and wall motion index (0.44 SD/chord [0.29 to 0.59 SD/chord], n=79 versus 0. 15 SD/chord [0.00 to 0.30 SD/chord], n=72, P=0.007) was significantly greater in patients assigned to abciximab than in those on heparin alone. At follow-up, the abciximab group had a higher global left ventricular ejection fraction than the heparin group (62% [59% to 65%] versus 56% [53% to 59%], P=0.003). CONCLUSIONS: Abciximab had important effects beyond the maintenance of large-vessel patency. It improved the recovery of microvascular perfusion and concomitantly enhanced the recovery of contractile function in the area at risk.

Abciximab↗

PubMed1998

Human CD34(+) thymocyte maturation: pre-T and NK cell differentiation on neonatal thymic stromal cell culture.

The development of a simple assay for studying human T and NK lymphopoiesis from CD34 progenitors is of great interest. T and NK cells arise from a common CD34(+) immature precursor. While T cell maturation is dependent on interactions and cytokines provided by thymic stromal cells. NK maturation does not require the thymic microenvironment and primarily takes place extrathymically. In addition to models using a mouse thymic microenvironment, in vitro assays based on coculture on human fetal thymic stroma have been described. As an alternative source of fetal thymic tissue we studied the capacity of neonatal thymic epithelial cell enriched stroma to support T and NK cell differentiation. While in the fetal-based assays on NK cells were observed under the conditions used for T cell differentiation, neonatal stroma can generate CD3/TcR+ as well as CD56(+)3(-)8(+)NKR-P1(+)NK cells from both CD34(+)1(-) and CD34(+)1(+) thymocyte precursors. However, following acquisition of CD3/TcR, T-lineage cells disappeared from the culture after 2-3 weeks as a consequence of the outgrowth of the NK cells. These CD56(+)3(-) NK cells appeared to be functionally immature as they required incubation with IL2 or IL15 to lyse K562 target cells. Our data offer a simple and reliable assay for studying the reconstitution potential of T and NK cell progenitors on a monolayer of thymic epithelial cells.

Animals↗

PubMed1998

[Cardiac pacemaker and internal defibrillators (ICD). Basic principles and new important developments, status 1998].

In recent years, treatment of cardiac arrhythmias with pacemakers and implantable cardioverter/defibrillators has become increasingly popular. Numerous technical developments have resulted in great advances in this area. International pacing letter coding for use with pacemakers defines the chamber(s) paced, the chamber in which the electrical activity is sensed, and the type of pacing. This also enables the family doctor involved in the care of the cardiac patient to identify the pacemaker system employed and provides him with initial orientation. New developments including VDD pacing, autocapture and autosensing are described and discussed. In a second part, the conditions for the use, and the manner of functioning, of modern implantable cardioverter/defibrillators are explained.

Defibrillators, Implantable↗

PubMed1998

Production of cytokines in patients infected by hepatitis C virus.

T helper type 1 (Th1) cytokines play an important role in antiviral defence. The purpose of this study was to quantify by ELISA IL2, soluble receptor of IL2 (IL2Rs), IFNgamma TNFbeta, IL4, IL6 and IL10 levels in the sera of 134 HCV-positive patients, 69 of whom were coinfected with HIV, and in 54 HIV-HCV-negative patients. The mean IL2Rs and IFN serum levels were much higher in patients with anti-HCV than in the control group, whereas the mean IL4 and IL6 levels were lower in patients infected with HCV. There were no significant differences in cytokine levels between patients with and without HIV. There were significantly less patients with HCV than controls with IFNgamma levels under cut-off, and significantly more patients with HCV with IL4 levels under cut-off. Although serum level of cytokines must be interpreted with caution, the results suggest that Th1 response is enhanced in HCV infection.

AIDS-Related Opportunistic Infections↗

PubMed1998

Restenosis rate after intravascular ultrasound-guided coronary stent implantation.

This study was designed to test the hypothesis that patients fulfilling intravascular ultrasound (IVUS) criteria for optimal coronary stent implantation show a reduction in the restenosis rate at 6 months. IVUS guidance for stent dilation may be associated with facilitated stent implantation and an increased acute luminal gain, but it has not yet been determined, whether and to what extent this procedure is associated with a reduction in the restenosis rate. IVUS-guided optimization of Palmaz-Schatz stent placement was performed in 125 consecutive patients, 64 of whom fulfilled IVUS-criteria for optimal stent placement. Another 125 patients served as the non-IVUS control group. In 107 patients (86%) of the non-IVUS control group and 105 patients (84%) of the IVUS group, angiographic follow-up was performed. The IVUS group of patients revealed a significantly lower restenosis rate of 20.9% as compared with 29.9% in the control group (P = 0.033). Patients that met IVUS criteria for optimal stent placement had a larger minimal lumen diameter immediately after stent implantation (3.13 +/- 0.44 vs. 2.95 +/- 0.47 mm; P = 0.045) and at 6-month follow-up (2.23 +/- 0.78 vs. 1.87 +/- 0.76 mm; P = 0.019) as well as a significantly lower restenosis rate (13.5% vs. 28.3%; P = 0.038) as compared with patients that did not fulfil these criteria. Our data suggest that patients fulfilling IVUS criteria for optimal stent placement demonstrate a reduced risk for the development of restenosis. Thus, IVUS investigation identifies factors predictive of restenosis after coronary stent placement.

Adult↗

PubMed1998

Highly sensitive DNA typing for detecting tumors transmitted by transplantation.

DNA typing of a variable number of tandem repeats (VNTRs) and of short tandem repeats (STRs) is a modern forensic method for the identification of biological material. In many cases, amplification by the polymerase chain reaction (PCR), especially of STRs, allows DNA typing of minute amounts of or degraded DNA. Here we describe the successful use of forensic DNA typing to clarify the origin of a malignant tumor. We report two cases of metastatic malignant melanoma of unknown origin that developed a few months after transplantation in two recipients of kidneys from the same donor. Fresh metastatic tissue and blood from the first recipient, reference DNA of the donor, and only paraffin-embedded tissue from the second recipient were available for analysis. To investigate whether the melanoma originated in the donor, DNA analysis of nine polymorphic loci was performed. The results of the analysis showed that, in both cases, the tumors were genetically different from the recipient DNA but matched the donor DNA. One incident of allele loss was attributed to a mutation event. We conclude that the metastatic melanoma in both recipients originated in the donor and was transmitted by renal transplantation.

Adult↗

PubMed1998

Inhibition of hepatitis C virus adsorption to peripheral blood mononuclear cells by dextran sulfate.

Human peripheral blood mononuclear cells (PBMC) can be infected in vitro with sera of hepatitis C virus (HCV)-infected patients. We have treated pools of PBMC with dextran sulfate MW 8,000, before infection with various HCV(+) sera. When the cells were treated with dextran sulfate 10-3 M, HCV RNA was no longer detectable after infection with all HCV genotypes tested. When the cells incubated with dextran sulfate 10-3 M and 10-4 M were maintained in culture for 4 weeks, no significant HCV replication could be observed. Our data suggest that dextran sulfate inhibits the attachment of HCV to the cell surface, since the HCV RNA detection was similar to control cells when dextran sulfate was added after infection.

Adsorption↗

PubMed1998

TAP, the human homolog of Mex67p, mediates CTE-dependent RNA export from the nucleus.

The constitutive transport element (CTE) of the type D retroviruses promotes nuclear export of unspliced viral RNAs apparently by recruiting host factor(s) required for export of cellular messenger RNAs. Here, we report the identification of TAP as the cellular factor that specifically binds to wild-type CTE but not to export-deficient CTE mutants. Microinjection experiments performed in Xenopus oocytes demonstrate that TAP directly stimulates CTE-dependent export. Furthermore, TAP overcomes the mRNA export block caused by the presence of saturating amounts of CTE RNA. Thus, TAP, like its yeast homolog Mex67p, is a bona fide mRNA nuclear export mediator. TAP is the second cellular RNA binding protein shown to be directly involved in the export of its target RNA.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

Data base management in interventional electrophysiology--the relational advantage.

UNLABELLED: A relational database was designed to facilitate patient management and storage of complex electrophysiologic data of patients undergoing radiofrequency catheter ablation. The database has to deal with multiple data entries per patient record like radiofrequency current applications and catheters. BACKGROUND: Due to the complexity of catheter mapping and ablation therapy, the investigators have to handle various data types. Contradictory to a flat-file database, a relational structured database is not limited to a "single record structure". IMPLEMENTATION: The designed database is built on the relational database programming environment 4th Dimension (ACI). It is implemented on an Apple Macintosh computer system. The relational structure consists of 13 data files and enables an unlimited data entry of multiple items per data field: In 1288 patients 10308 radiofrequency current applications were applied for ablation therapy and 4798 diagnostic or therapeutic catheters were used.

Arrhythmias, Cardiac↗

PubMed1998

FISH detection of chromosome 14q32/IgH translocations: evaluation in follicular lymphoma.

A FISH strategy capable of detecting chromosome 14q32 rearrangements involving the IgH locus, including in interphase nuclei, was developed using Ig variable and constant region cosmids from the extremities of the locus in a dual hybridization approach, using signal splitting as evidence of rearrangement. The large size of the locus (1.3 Mb) and the propensity for internal deletion due to physiological VDJ recombination and isotype switching complicate analysis of this locus. We used the Ig10 cosmid, which hybridizes to C epsilon and C alpha2 at the 3' end of the constant region, in order to minimize deletion and/or splitting of the constant region probe. Cos Ig10 and the IgV18 VH probes were compared with a specific IgH-BCL2 FISH dual hybridization approach in follicular lymphoma (FL). Both were capable of detecting the t(14;18) in interphase nuclei, including in cases with no apparent abnormality by classic karyotype analysis, although the sensitivity of the IgH approach was slightly lower. We have also successfully applied these probes to whole cell cytospin preparations, rendering analysis of cryopreserved material possible, although interpretation should be limited to frequent events, particularly following cell manipulation. Analysis of flow cytometric sorted bone marrow fractions from three FL patients by FISH and FICTION showed that the t(14;18) was present in a much lower proportion of CD34 positive than negative cells but that the higher level of background hybridization limits use of these techniques for the reliable quantification of rare events.

Cell Separation↗

PubMed1998

Structure and technofunctional properties of protein-polysaccharide complexes: a review.

Food proteins and polysaccharides are the two key structural entities in food materials. Generally, interactions between proteins and polysaccharides in aqueous media can lead to one- or two-phase systems, the latter being generally observed. In some cases of protein-polysaccharide net attraction, mainly mediated through electrostatic interactions, complex coacervation or associative phase separation occurs, giving rise to the formation of protein-polysaccharide complexes. Physicochemical factors such as pH, ionic strength, ratio of protein to polysaccharide, polysaccharide and protein charge, and molecular weight affect the formation and stability of such complexes. Additionally, the temperature and mechanical factors (pressure, shearing rate, and time) have an influence on phase separation and time stability of the system. The protein-polysaccharide complexes exhibit better functional properties than that of the proteins and polysaccharides alone. This improvement could be attributed to the simultaneous presence of the two biopolymers, as well as the structure of the complexes. Consequently, the interesting hydration (solubility, viscosity), structuration (aggregation, gelation) and surface (foaming, emulsifying) properties of these complexes can be used in a number of domains. Among others, these could be macromolecular purification, microencapsulation, food formulation (fat replacers, texturing agents), and synthesis of biomaterials (edible films, artificial grafts).

Biopolymers↗

PubMed1998

The importance of stabilization as an endpoint in the treatment of metastatic colorectal carcinoma: recent quality of life studies.

Assessment of the effectiveness of new anticancer chemotherapies in clinical trials is usually based on the degree of objective response obtained. Response is usually defined as 'complete', when there is complete disappearance of all detectable tumor, or 'partial', when there is a 50% reduction in the sum of the products of the largest perpendicular diameters of all measurable disease, with no new lesions (Advanced Colorectal Cancer Meta-analysis Project). Both clinicians, concerned with the welfare of their patients, and healthcare administrators, keen to be assured of cost-effectiveness within their restricted budgets, see such response (along with enhanced survival) as a cardinal indicator of efficacy. Response rates are a primary influence on their decision to treat, or to sanction payment for treatment, with a particular medication. There is, however, growing evidence to suggest that stabilization of disease is also an important endpoint in chemotherapy for carcinoma, with important benefits for the patients' quality of life (QoL). We report on recent international studies on the effects of the topoisomerase I inhibitor irinotecan (Campto) as second-line treatment in patients with metastatic colorectal cancer. These confirm the value of stabilization, as well as response, in such patients, not only in bringing QoL benefits, but also in reducing length of hospitalization and hence costs.

Colorectal Neoplasms↗

PubMed1998

Frequency dependence in the action of the class III antiarrhythmic drug dofetilide is modulated by altering L-type calcium current and digitalis glucoside.

We investigated how modulation of L-type calcium current affects the class II antiarrhythmic effect of dofetilide. Action-potential duration (APD) was determined in guinea pig papillary muscle by microelectrode techniques at different stimulation frequencies (0.5-3 Hz). The APD-prolonging effect (deltaAPD) of 10 nM dofetilide was reversed frequency dependent; it was 51 +/- 6 ms at 0.5 Hz and lower at 3 Hz, 21 +/- 3 ms. Either 10 microM diltiazem or 0.1 microM Bay K 8644 (BayK) was added to decrease or increase L-type calcium currents. In the presence of dofetilide + diltiazem, deltaAPD was reduced to 32 +/- 4 ms at 0.5 Hz but not affected at 3 Hz. Conversely, dofetilide + BayK further prolonged deltaAPD to 78 +/- 10 ms at 0.5 Hz but not at 3 Hz. When 10 microM dihydroouabain, a digitalis glucoside, was added to dofetilide, deltaAPD was more pronounced at 0.5 Hz and reduced at 3 Hz. We conclude that the reversed frequency-dependent effect of dofetilide on APD can be modulated by altering L-type calcium currents. With reduced calcium current, the frequency profile is less reversed and more favorable. The similarity of BayK and dihydroouabain in aggravating the reversed frequency-dependent effect of dofetilide is in line with a contribution of intracellular calcium to this reversed rate-dependent profile in the guinea pig ventricle.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗