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Biomedical subjects

J Winter

Publications and source records attributed to J Winter.

At least 145 records · Page 8Linked to original sources
PubMed1993

Defibrillation energy requirements with single endocardial (Endotak) lead.

The need for thoracotomy in usually high risk patients has limited the use of the implantable cardioverter defibrillator. Initial clinical results with endocardial and subcutaneous patch electrodes (SQPs) are encouraging. Using a single endocardial lead in the absence of a SQP for chronic implantation of the cardioverter defibrillator, the goal of the study was to obtain defibrillation thresholds (DFTs) of 15 Joules (J) or less and to investigate changes in DFT over time. We tested 19 consecutive patients (15 men, 4 women) age 62 +/- 8.5 years with malignant ventricular arrhythmias (14 VT/5 VF). The underlying heart disease was coronary artery disease in 15 patients, dilative cardiomyopathy in two patients, and primary electrical disease in two patients. Four patients had undergone previous cardiac surgery. Left ventricular ejection fraction ranged between 14% and 66% (39% +/- 12.6%). Pacing thresholds (0.54 +/- 0.17 V at 0.5 msec), R wave amplitude for pacemaker sensing (14.2 +/- 7.0 mV), slew rate (2.12 +/- 1.4 V/sec), and resistance (500.3 +/- 73.9 W) were sufficient in all patients. Eighteen patients met our endocardial implant criteria with a DFT < or = 15 J (10.05 +/- 4.03 J) using monophasic (14 patients) or biphasic (four patients) pulse wave forms. In the one remaining patient, with a DFT of 20 J, we implanted a SQP but there was no reduction of the DFT. All patients tested showed successful defibrillation prior to discharge. During follow-up of 88 patient-months (1-9 months), 114 spontaneous VT/VF episodes occurred in five patients and were all successfully terminated. Eleven patients with a minimum follow-up of 2 months were reassessed.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Pacing, Artificial↗
PubMed1993

Phase I trial of the diphtheria toxin/interleukin-2 fusion protein DAB486IL-2: efficacy in mycosis fungoides and other non-Hodgkin's lymphomas.

The purpose of this study was to investigate the biologic activity of DAB486IL-2 when administered three times daily, in terms of toxicity, pharmacokinetics, and anti-tumor effects in patients with IL-2R expressing hematologic malignancies, especially mycosis fungoides. 20 patients were enrolled in this dose escalation phase I trial. Patient cohorts were treated at levels of 0.03 mg/kg, 0.05 mg/kg, 0.07 mg/kg and 0.09 mg/kg every 8 hours for a total of 12 doses, every 21 days as toxicity and response warranted. Eight patients experienced transient fevers associated with DAB486IL-2 administration. One patient experienced grade 3 hypotension, and a second developed fluid retention manifested as weight gain/pedal edema. Dose limiting toxicity consisted of one episode of transient grade 4 hepatic transaminase elevation, and 8 episodes of transient asymptomatic grade 3 hepatic transaminase elevation. At the maximum tolerated dose DAB486IL-2 exhibited biphasic clearance kinetics; transient receptor saturation may be one mechanism for this observation. Initial serum concentration and apparent steady state level (plateau) directly correlated with the dose administered, but no difference in area under the concentration curve with greater dose was observed. Biologic activity was noted in patients with mycosis fungoides with skin lesion clearing and relief of pruritus. One patient with mycosis fungoides, and one patient with a relapsed intermediate grade non-Hodgkin's lymphoma achieved partial responses. The novel mechanism of action, toxicity profile, and evidence of biologic activity in refractory cancer patients, support development of more active constructs of this agent; such trials are underway.

Adult↗
PubMed1993

[The common channel syndrome in adults].

Congenital abnormalities of the distal bile and pancreatic duct occur predominantly as a long common channel. A common channel of more than 15 mm is considered abnormal, since the length allows a reflux of pancreatic secretion into the bile duct and vice versa. The very rare occurrence of a long common channel syndrome in adults has been observed in two female patients (24 and 58 years old). Both presented cholangitis and/or pancreatitis. Diagnosis was established by ERCP. The definitive therapy in both cases was hepatico-jejunal anastomosis which improved symptoms in both patients. Endoscopic sphincterotomy is unsatisfactory since it does not cut the entire common channel. The rare etiology of a long common channel in patients with cholangitis and pancreatitis is safely verified by ERCP and safely cured by surgical intervention.

Acute Disease↗
PubMed1992

Neurotoxic damage evokes regenerative responses from adult rat sensory neurones.

When adult rats were pre-treated systemically with the excitotoxin, capsaicin, a subset of their dorsal root ganglion (DRG) sensory neurones responded as if they had been axotomised. Firstly, an increased proportion of capsaicin-sensitive DRG neurones (identified by using a cobalt stain) vigorously extended processes in vitro. Additionally, a subset of small dorsal root ganglion neurones expressed elevated levels of the growth-associated protein-43 (GAP-43) in situ. Both vigorous neuritogenesis and elevated GAP-43 levels are characteristics of neurones that are actively regenerating following mechanical damage. Although capsaicin-treated adult DRG neurones show these regenerative responses, their C-fibers fail to regenerate in vivo.

Animals↗
PubMed1992

Regulation of expression of the neuronal POU protein Oct-2 by nerve growth factor.

POU proteins are a class of homeobox-containing transcription factors that regulate tissue-specific gene expression and influence cell differentiation and function. We have investigated the possible role of such factors in mediating the actions of nerve growth factor (NGF) on sensory neurons. NGF has been found to have differential effects on the levels of three POU protein transcription factors that are expressed in adult rat sensory neurons. A sensory neuron octamer-binding protein with the properties of the transcription factor Oct-2 is up-regulated 3-4-fold by NGF, as measured by mobility shift assays using nuclear extracts from adult rat dorsal root ganglion neurons grown in the presence or absence of NGF. Quantitation of Oct-2 mRNA by polymerase chain reaction amplification of RNA from such cells shows a parallel increase in Oct-2 mRNA levels. In contrast, the levels of mRNA encoding the ubiquitous POU protein Oct-1 or the neuron-specific POU protein Brn-3, also present in sensory neurons, are unaffected by NGF. These observations suggest a role for Oct-2 in mediating transcriptional effects induced by NGF. In particular, as Oct-2 is known to inhibit herpes simplex virus immediate-early gene expression in neuronal cells, these findings provide a mechanism for the known action of NGF in the maintenance of latent herpes virus infections in sensory neurons.

Animals↗
PubMed1992

Regional differences in the distribution of capsaicin-sensitive target-identified adult rat dorsal root ganglion neurons.

A retrograde labelling technique combined with a cobalt uptake assay in cultured adult rat dorsal root ganglion (DRG) neurons were applied to study the distribution of capsaicin sensitivity in relation to different peripheral targets. This study shows that there are regional differences between skin, skeletal muscle and urinary bladder; 20-30% of skin afferents, 40% of muscle afferents and 60% of bladder afferents were found to be capsaicin-senditive. This may reflect differences in the proportion of chemosensitive afferents innervating different peripheral tissues.

Animals↗
PubMed1992

Purification and characterization of benzoyl-CoA ligase from a syntrophic, benzoate-degrading, anaerobic mixed culture.

The benzoyl-CoA ligase from an anaerobic syntrophic culture was purified to homogeneity. It had a molecular mass of around 420 kDa and consisted of seven or eight subunits of 58 kDa. The temperature optimum was 37-40 degrees C, the optimum pH around 8.0 and optimal activity required 50-100 mM TRIS-HCl buffer, pH 8.0 and 3-7 mM MgCl2; MgCl2 in excess of 10 mM was inhibitory. The activation energy for benzoate was 11.3 kcal/mol. Although growth occurred only with benzoate as a carbon source, the benzoyl-coenzyme A (CoA) ligase formed benzoyl-CoA esters with benzoate, 2-, 3- and 4-fluorobenzoate, picolinate, nicotinate and isonicotinate. Acetate was activated to acetyl-CoA by an acetyl-CoA synthetase. The Km values for benzoate, 2-, 3- and 4-fluorobenzoate were 0.04, 0.28, 1.48 and 0.32 mM, the Vmax values 1.05, 1.0, 0.7 and 0.98 units (U)/mg, respectively. For reduced CoA (CoA-SH) a Km of 0.07 mM and a Vmax of 1.05 U/mg and for ATP a Km of 0.16 mM and a Vmax of 1.08 U/mg was determined. Benzoate activation was inhibited by more than 6 mM ATP, presumably by pyrophosphate generation from ATP. The inhibition constant (Ki) for pyrophosphate was 5.7 mM. No homology of the N-terminal amino acid sequence with that of a 2-aminobenzoyl-CoA ligase of a denitrifying Pseudomonas sp. was found.

Acetate-CoA Ligase↗
PubMed1992

Factors influencing local relapse and survival and results of salvage treatment after breast-conserving therapy in operable breast cancer: EORTC trial 10801, breast conservation compared with mastectomy in TNM stage I and II breast cancer.

A (modified) radical mastectomy (RM) was compared with breast-conserving therapy (BCT) in stage I and stage II breast cancer patients. Treatment of the study arm comprised lumpectomy, axillary clearance and radiotherapy to the breast (50 Gy in 5 weeks external irradiation and a boost with iridium implant of 25 Gy). 902 patients were included. There were 734 TNM stage II patients. Patients with microscopically incomplete excision of the tumour were not excluded. After a median follow-up of 6 years, overall survival and local recurrence rates do not differ significantly between the two study arms. Actuarial survival at 8 years was 73% after RM and 71% after BCT; actuarial local recurrence at 8 years was 9% and 15%, respectively. In the mastectomy group tumour size did not affect local relapse, but after BCT the incidence of local recurrences was higher for tumours of 2-5 cm (16%) than for smaller tumours (7%) (at 8 years, P = 0.08). Results of salvage treatment for local recurrence so far were similar in both the BCT and the mastectomy group.

Aging↗
PubMed1992

Transcutaneous cardiac pacing in patients with automatic implantable cardioverter defibrillators and epicardial patch electrodes.

In patients with automatic implantable cardioverter defibrillators, insulation of the epicardial patch electrodes (patches) prevents externally applied current from passing through the electrode to the cardiac muscle so that external transthoracic and even internal defibrillation can be unsuccessful. Because emergency cardiac pacing may be required in such a case, a study was performed to evaluate whether, and at what threshold and electrode orientation, transcutaneous pacing is possible in patients with implanted patches. Thresholds for transcutaneous pacing were determined during general anesthesia in nine patients with patches sewn across the heart (anterior right and posterior left ventricles) either before or after surgery, or at both times (automatic implantable cardioverter defibrillator implantation/exchange with or without coronary artery bypass grafting). Because surgery per se can increase the pacing threshold, nine patients of similar body size and weight undergoing routine coronary artery bypass grafting also were evaluated and served as a control group. Pacing thresholds (stimulus duration: 50 ms) were determined during normothermia with a transportable transcutaneous pacer, and adult cutaneous electrodes were placed across the patients' chest in the standard anteroposterior and right-to-left orientations. In all patients with patch electrodes, antero-posterior pacing was possible at a mean threshold of 73 +/- 30 mA standard deviation (range: 40-140 mA). This threshold was not significantly different (Mann-Whitney test) from that in control patients before (57 +/- 20 mA; range: 30-90 mA) or after (94 +/- 24 mA; range: 40-120 mA) coronary artery-bypass grafting. The surgical procedure per se significantly increased the threshold (Wilcoxon test, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Pacing, Artificial↗
PubMed1992

GAP-43 mRNA in Rat Spinal Cord and Dorsal Root Ganglia Neurons: Developmental Changes and Re-expression Following Peripheral Nerve Injury.

The expression of growth-associated protein GAP-43 mRNA in spinal cord and dorsal root ganglion (DRG) neurons has been studied using an enzyme linked in situ hybridization technique in neonatal and adult rats. High levels of GAP-43 mRNA are present at birth in the majority of spinal cord neurons and in all dorsal root ganglion cells. This persists until postnatal day 7 and then declines progressively to near adult levels (with low levels of mRNA in spinal cord motor neurons and 2000 - 3000 DRG cells expressing high levels) at postnatal day 21. A re-expression of GAP-43 mRNA in adult rats is apparent, both in sciatic motor neurons and the majority of L4 and L5 dorsal root ganglion cells, 1 day after sciatic nerve section. High levels of the GAP-43 mRNA in the axotomized spinal motor neurons persist for at least 2 weeks but decline 5 weeks after sciatic nerve section, with the mRNA virtually undetectable after 10 weeks. The initial changes after sciatic nerve crush are similar, but by 5 weeks GAP-43 mRNA in the sciatic motor neurons has declined to control levels. In DRG cells, after both sciatic nerve section or crush, GAP-43 mRNA re-expression persists much longer than in motor neurons. There was no re-expression of GAP-43 mRNA in the dorsal horn of the spinal cord after peripheral nerve lesions. Our study demonstrates a similar developmental regulation in spinal cord and DRG neurons of GAP-43 mRNA. We show moreover that failure of re-innervation does not result in a maintenance of GAP-43 mRNA in axotomized motor neurons.

Journal Article↗
PubMed1992

Regulation of afferent connectivity in the adult spinal cord by nerve growth factor.

During development, nerve growth factor (NGF) regulates the density and character of peripheral target innervation (Barde, Neuron, 2, 1525 - 1534, 1989; Ritter et al., Soc. Neurosci. Abstr., 17, 546.2, 1991); its role in adult animals is less well defined. Here we have asked if the availability of growth factors such as NGF in peripheral tissues can influence the pattern of primary afferent connections in the CNS. Using osmotic minipumps, we raised the levels of NGF in rat skeletal muscle in vivo, a tissue where the levels of this factor are normally very low (Korsching and Thoenen, Proc. Natl. Acad. Sci. USA, 80, 3513 - 3516, 1983; Shelton and Reichardt, Proc. Natl. Acad. Sci. USA, 81, 7951 - 7955, 1984; Goedert et al., Mol. Brain Res., 1, 85 - 92, 1986). After 2 weeks of treatment we asked if the sensory neurons innervating this tissue showed an altered strength and distribution of connections with dorsal horn neurons. The contralateral (vehicle-treated) muscle, and totally untreated animals, served as controls. In normal and vehicle-treated animals, electrical stimulation of muscle afferents excited relatively few neurons in the dorsal horn, and these generally showed only weak responses. In contrast, on the NGF-treated side many more dorsal horn neurons in the lumbar enlargement of the spinal cord were excited by muscle afferents. The increased responsiveness could not be explained by a generalized increase in dorsal horn excitability, since spontaneous activity was not enhanced, nor by a change in A-fibre-mediated inhibitions from the treated afferents. Thus, these afferents appeared to establish new synaptic connections or strengthened previously weak ones as a result of increased neurotrophic factor availability. The data suggest that, in the adult rat, the levels of growth factors in peripheral targets may be used to regulate an appropriate degree of afferent connectivity within the central nervous system.

Journal Article↗
PubMed1992

Immunologic findings in tissue of thyroid carcinoma.

We studied the occurrence of DR-antigen (DR-Ag) positive thyroid epithelial cells (TEC), lymphocyte (Ly)-subsets, and antigen-presenting cells (APC) in thyroid carcinoma and the influence of thyroid-stimulating hormone (TSH) on immunologic behavior. Tissue slices from various thyroid carcinomas (n = 14) and endemic goiters (n = 12) were investigated by immunohistochemical methods (PAP/APAAP/FITC) using monoclonal antibodies (MoAbs) against DR-Ag, dendritic cells (APC), endothelial cells, CD-3 Ly, CD-4 Ly, and CD-8 Ly. Monolayers of TEC were cultured in the presence or absence of TSH (0.01 mU/ml) and/or PHA (0.1 mg/ml) over 24 h and screened for DR-Ag expression. Various ranges of DR-Ag expression were detectable in 13 thyroid carcinomas. One thyroid carcinoma and all endemic goiters were DR-Ag-. The amount of APC and local infiltrating Ly correlated very well with the presence and intensity of DR-Ag+ TEC. The lymphocytic CD-4/CD-8 ratio varied in a wide range. No prevalence of Ly-distribution for any type of carcinoma was found. PHA induced DR-Ag expression in all thyroid carcinomas and endemic goiters. This effect was enhanced significantly by TSH. DR-Ag expression on thyroid carcinoma cells may be considered as an immune activating factor. These "neoantigens" may be induced by lymphokines released by the local immune competent cells. The distribution of Ly and DR-Ag+ TEC in thyroid carcinoma seems to represent the individual immunologic response against the tumor. Whether TSH acts as an immune modulator directly or indirectly, as described elsewhere, cannot be concluded from these results.

Antigens, Neoplasm↗
PubMed1992

Randomized clinical trial to assess the value of breast-conserving therapy in stage I and II breast cancer, EORTC 10801 trial.

In a prospective randomized clinical trial conducted by the European Organization for Research and Treatment of Cancer (EORTC), mastectomy was compared with breast-conserving therapy in 903 stage I and stage II breast cancer patients entering the study between 1980 and 1986. The main participating centers were: Guy's Hospital, London; The Netherlands Cancer Institute, Amsterdam; University Hospital, Leuven; Radiotherapy Institute, Rotterdam; Breast Unit, Tijgerberg, S.A. The data were collected in the EORTC Data Center, Brussels. Treatment in the study arm consisted of lumpectomy, axillary clearance, and radiotherapy to the breast (50 Gy external irradiation in 5 weeks followed by boost with iridium implant of 25 Gy). Important in this study is the large number of TNM stage II patients (755). Most patients were stage II because of the size of the tumor (2-5 cm). The patient and tumor characteristics in the study and control groups were well balanced. So far the survival curves and local recurrence rates are not statistically different for the two study arms. Tumor size was found in univariate analysis to be a significant risk factor for local recurrence in the breast-conserving therapy group but not in the mastectomy group. Results of salvage treatment for local recurrence were not better for the breast-conserving therapy group compared with the mastectomy group. Measurements of quality of life and cosmesis show a clear benefit for the breast-conserving therapy group.

Adult↗