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Biomedical subjects

M Weiss

Publications and source records attributed to M Weiss.

At least 37 records · Page 2Linked to original sources
PubMed1995

Stereoselective suppression of neutrophil function by ketamine?

The effects of the commercially available ketamine preparation (Ketanest), the ketamine racemate and of the two enantiomers, the R(-)-racemate and the S(+)-racemate, as well as its drug-free solvent were examined by N-formyl-methionyl-leucyl-phenylalanine-(FMLP)- and zymosan-induced oxygen radical production of polymorphonuclear cells (PMN). The racemate and the two enantiomers of ketamine suppressed FMLP- and zymosan-induced chemiluminescence of PMN in a dose-dependent fashion to the same extent. Therefore suppression of chemiluminescence of PMN by ketamine does not result from a specific receptor interaction.

Cell-Free System↗
PubMed1995

[Studies of facilities with increased abortion rates in cattle].

Cases of abortions in cattle were investigated using several different laboratory procedures. The purpose was to collect information on an individual animal and on a herd basis that would allow a correct etiological diagnosis and also the institution of prophylactic measures. The cause of the abortion was diagnosed in 30% of the cases and in 16.3% of the herds. Due to the complexity of the problem, there is no routine diagnostic procedure that can universally be recommended and applied. There was no association between the number of tests performed or the number of herd mates included in the diagnostic work-up and the diagnostic success rate. In order to make a more efficient use of the diagnostic procedures, a better understanding of the mechanisms leading to abortion, on an individual animal basis and on a herd basis, is required.

Abortion, Veterinary↗
PubMed1995

Spontaneous regression of hepatocellular carcinoma.

Spontaneous regression of cancer is a rare phenomenon seldom described in patients with hepatocellular carcinoma. A case of spontaneous regression of hepatocellular carcinoma is reported and compared with the reports published in the English literature. A 52-yr-old man presented with biopsy-proven hepatocellular carcinoma, which was considered to be unresectable at initial laparotomy. The tumor subsequently regressed without specific treatment, as assessed radiologically and by normalization of a previously elevated alpha-fetoprotein level. At repeat laparotomy 14 months after initial diagnosis, intraoperative ultrasound failed to disclose a hepatic mass, and multiple biopsies showed no evidence of malignancy. To date, only nine case reports of apparently spontaneous regression of hepatocellular carcinoma have been published in the English literature. Clinical characteristics discriminating these patients from less fortunate patients with hepatocellular carcinoma could not be identified. The mechanisms underlying this intriguing phenomenon remain unknown.

Biopsy↗
PubMed1995

Elder abuse and neglect: how to recognize warning signs and intervene.

Elder mistreatment, whether abuse or neglect, can be classified as physical, psychological, or financial/material. Several types of mistreatment may occur simultaneously. Abuse occurs across all socioeconomic, racial, and religious lines. Risk factors include a history of mental illness or alcohol/drug abuse, a family history of violence, isolation of the victim, and recent stressful events in the life of the victim or abuser. For the physician the patient workup includes a careful history and physical exam, including cognitive evaluation. Ask about living arrangements, financial status, social supports, and emotional stressors. If possible, observe the interaction between the patient and family member or caregiver. Helpful resources include your state's Office of Protective Services and the American Medical Association's recently published guidelines for diagnosis and treatment of elder abuse and neglect.

Aged↗
PubMed1995

Paradoxical blockade of beta adrenergically mediated inhibition of stimulated eosinophil secretion by salmeterol.

Salmeterol (SALM) is a long-acting beta 2 adrenoceptor agonist that causes prolonged relaxation of airway smooth muscle. To determine whether this agent also causes prolonged inhibition of stimulated eosinophil secretion, we studied interactions between SALM and albuterol (ALB) in inhibiting eosinophil peroxidase (EPO) secretion in human eosinophils in vitro. Peripheral blood eosinophils were isolated from 18 human volunteers by negative immunoselection, and secretion of EPO was elicited with 10(-6) M formyl-met-leu-phe (fMLP) + 5 micrograms/ml cytochalasin B (CytB) in aliquots of 10(5) cells. Eosinophils were pretreated with either 10(-8) M ALB, 10(-8) M SALM or SALM + ALB for 5 min to 18 hr at 37 degrees C. Pretreatment with ALB for 5 min caused inhibition of stimulated secretion of EPO to 783 +/- 210 ng/10(6) cells vs. 1475 +/- 286 ng/10(6) cells for eosinophils not treated with ALB (P < .05; n = 5). Inhibition of EPO secretion caused by ALB was sustained for 30 min (924 +/- 160 ng/10(6) cells; P < .05 vs. fMLP + CytB; n = 5). By contrast, SALM had no inhibitory effect on fMLP-induced secretion after incubation for 5 min to 18 hr. In cells obtained from four separate isolations, pretreatment with 10(-8)M SALM before addition of ALB blocked the inhibition of EPO release caused by 10(-8)M ALB alone (486 +/- 28 ng/10(6) cells for ALB alone vs. 902 +/- 32 ng/10(6) cells for SALM + ALB; P < .01; n = 4).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗
PubMed1994

An early haematopoietic defect in mice lacking the transcription factor GATA-2.

Blood cell development relies on the expansion and maintenance of haematopoietic stem and progenitor cells in the embryo. By gene targeting in mouse embryonic stem cells, we demonstrate that the transcription factor GATA-2 plays a critical role in haematopoiesis, particularly of an adult type. We propose that GATA-2 regulates genes controlling growth factor responsiveness or the proliferative capacity of early haematopoietic cells.

Anemia↗
PubMed1994

Reduction of the incidence of rejection by adjunct immunosuppression with photochemotherapy after heart transplantation.

In this study, photochemotherapy (PCT) was used for adjunct immunosuppression in the first six months after heart transplantation (HTx). Fifteen patients after orthotopic HTx were included in the study; all received standard triple-drug immunosuppression including cyclosporine, azathioprine and glucocorticoids, but no adjunct therapy with mono- or polyclonal antibodies. The patients were divided into three groups: group I served as control with no additional treatment; group II received adjunct treatment with 10 courses of PCT (single-day treatments); and group III received 20 PCT courses since it was given each time on two consecutive days. PCT was started in both groups on day one after HTx; it was applied with a higher frequency in the early postoperative period and thereafter continued at four-week intervals for a total of 6 months. The photopheresis method for PCT included extracorporeal UVA irradiation of mononuclear cells that were treated with the photosensitive drug 8-methoxypsoralen (8-MOP) and subsequently retransfused to the patient. A new liquid form of 8-MOP was added directly to the buffy coat, resulting in reliable and sufficient drug levels in the cell suspension during the irradiation period; problems caused by oral application due to unpredictable variations in gastrointestinal absorption were thus prevented. Analysis of the total numbers of acute rejection episodes (AREs) within the first four weeks after HTx revealed a more impressive decrease by double PCT (group III, 3 AREs) than by single PCT (group II, 5 AREs) in comparison with the control (group I, 6 AREs). Over the total observation time (mean: 9.6 months), however, both PCT schedules reduced the total number of AREs observed in the control group (20 AREs) equally by more than 50% (9 AREs each in groups II and III) (P = 0.007). Furthermore, PCT treated patients had significantly fewer infections (6 infections in each group) than control group patients (15 infections) (P = 0.026); this, however, may be accounted for by the higher number of acute rejections in the control group and consequent increase in unspecific immunosuppression treatment. Our results suggest that PCT is a safe and effective method of adjunct immunosuppression that can be applied early in the postoperative period; it reduces the number of rejection episodes and does not increase the risk of infections.

Adult↗
PubMed1994

CNRS defended.

Explore the source record for details and available documents.

France↗
PubMed1994

A comparison of clinical, pathological and radiological findings with magnetic resonance imaging studies of lymphomas in patients with Sjögren's syndrome.

In the past few years a variety of papers on magnetic resonance imaging (MRI) of the salivary glands have been published, mainly focusing on the evaluation of salivary gland tumors. More recently, non-tumorous lesions have also been examined with this imaging technique. In Sjögren's syndrome (SS) a characteristic inhomogeneous pattern with a "honeycomb-like" appearance of the parotid gland tissue has been shown in the T2-weighted sequence. This study shows MRI findings in four cases of intraglandular lymphoma occurring in patients with SS. Four patients with suspected lymphomas were examined with MRI, following which all lesions were either biopsied or removed. This enabled us to correlate clinical, radiological and pathological findings. Results indicate that MRI is a useful imaging tool in the detection of intraglandular lymphatic infiltrates, although it is not possible to distinguish morphologically between a localized lymphatic infiltrate and an early stage malignant lymphoma. Nevertheless, MRI is considered to be a valuable non-invasive method for deciding whether or not to perform a biopsy. Due to the excellent soft tissue differentiation obtained, it is also helpful for the surgeon to plan and perform a successful biopsy with minimal risk to the facial nerve.

Aged↗
PubMed1994

Capillary leak syndrome associated with elevated IL-2 serum levels after allogeneic bone marrow transplantation.

The pathophysiological mechanisms involved in the development of a spontaneous systemic capillary leak syndrome (CLS) are unknown. In contrast, CLS is a well-known side effect of high-dose interleukin-2 (IL-2) therapy in solid tumors. We report on a patient who developed CLS with high serum levels of endogenous IL-2 under immunosuppressive therapy for chronic graft-versus-host disease (GvHD) after allogeneic bone marrow transplantation (BMT). Generalized edema persisted for 10 weeks. The condition resolved after antibiotic therapy of a septic shock with beta hemolyzing streptococci group A. Thus, a latent infection may alter cytokine homeostasis and may cause CLS in BMT patients.

Adult↗
PubMed1994

Stereotactic core needle biopsy of mammographic breast lesions as a viable alternative to surgical biopsy.

BACKGROUND: Stereotactic needle biopsy technique has received considerable attention as a possible alternative to surgical biopsy of nonpalpable breast lesions. The exact role of this procedure in the management of mammographic breast lesions has not yet been accurately defined. METHODS: Data have been collected prospectively on 416 patients over an 8-month period (January 1992 through August 1992). Of 416, 356 patients underwent only stereotactic breast biopsy with a 14-gauge needle. Sixty patients underwent stereotactic breast biopsy followed by surgical biopsy. Based on mammographic findings before biopsy, lesions were classified as benign (24%), likely benign (49%), malignant (2%), likely malignant (6%), and indeterminate (19%). The number of core biopsy specimens obtained from each patient ranged from one to six. RESULTS: The specimen was considered adequate in 98% of cases. Complications were minimal. The tissue diagnosis was benign in 92% and malignant in 8% of patients. In those patients undergoing surgical and stereotactic biopsy, 57 of 60 had matching histopathological results, representing an agreement rate of 95% (p < 0.001). The three patients whose histopathological results did not match had malignant diagnoses on stereotactic biopsy that were subsequently not identified in the modified radical mastectomy specimen because the entire focus of malignancy was removed by the several passes made by the core needle during biopsy. No patient had a negative stereotactic biopsy result in whom malignancy was later detected by surgical biopsy. CONCLUSIONS: This study indicates excellent agreement between surgical and stereotactic needle biopsy findings. Stereotactic biopsy with a 14-gauge needle could obviate the need for surgical biopsy in certain women with radiologically benign, likely benign, and indeterminate lesions.

Algorithms↗
PubMed1994

Lung preservation with Euro-Collins, University of Wisconsin, Wallwork, and low-potassium-dextran solution. Université++ Paris-Sud Lung Transplant Group.

Using isolated rat lungs, we compared prevention of ischemia-reperfusion injury provided by flushing the lungs with modified Euro-Collins solution (EC), University of Wisconsin solution (UW), low-potassium-dextran solution (LPD), or Wallwork solution (WA). After 4 hours' and 6 hours' cold ischemia, reperfusion injury was assessed on the basis of changes in filtration coefficients (Kfc) and pressure-flow curves, characterized by the slope of the curves (incremental resistance) and the extrapolation of this slope to zero flow (pulmonary pressure intercept [Ppi]). After 4 hours, Kfc and Ppi were higher with EC than with UW, LPD, and WA, and the incremental resistance was higher with EC and UW. After 6 hours, Kfc and incremental resistance Ppi were higher with LPD than with WA. Because ischemia-reperfusion injury is associated with decreased endothelial synthesis of prostacyclin and nitric oxide, we tested whether the addition of prostacyclin or the nitric oxide precursor L-arginine to WA would improve preservation. The Kfc and Ppi were lower with both treatments. In conclusion, ischemia-reperfusion injury was best prevented by using WA. The favorable effect of prostacyclin or L-arginine emphasizes the role played by endothelial dysfunction in ischemia-reperfusion injury.

Adenosine↗
PubMed1994

Do barbiturates impair zymosan-induced granulocyte function?

PURPOSE: The dose-response relationship of commercially available preparations of methohexital, pentobarbital, phenobarbital, and thiopental and their respective drug-free solutions on granulocyte function was investigated to evaluate whether suppression of neutrophil chemiluminescence is mediated by the barbiturates themselves or by their drug-free solutions. Furthermore, it was assessed whether suppression of chemiluminescence is due to an interaction mainly with neutrophils or to free radical scavenging. METHODS: The dose-response effects of the four barbiturates on granulocyte function were tested by zymosan-induced neutrophil chemiluminescence and, in addition, in a cell-free chemiluminescence system. RESULTS: Methohexital and pentobarbital did not influence zymosan-induced neutrophil chemiluminescence, whereas phenobarbital and thiopental decreased neutrophil chemiluminescence in a dose-dependent fashion. Nonphysiological osmolality (531 mosmol/kg) caused this impaired neutrophil chemiluminescence at the greatest concentration of phenobarbital. Thiopental solely suppressed neutrophil chemiluminescence drug specifically. Because thiopental also reduced chemiluminescence generated in a cell-free system, free radical scavenging might contribute to the impaired neutrophil chemiluminescence observed with thiopental. CONCLUSIONS: With the exception of thiopental, barbiturates do not impair oxygen radical production during phagocytosis of neutrophils.

Cell-Free System↗
PubMed1994

Experimental evaluation of Celsior, a new heart preservation solution.

An original heart preservation solution (Celsior) has been developed, the formulation of which has been designed to fulfil two major objectives: (1) to combine the general principles of hypothermic organ preservation with those specific for the myocardium, and (2) to offer the possibility of being used not only as a storage medium but also as a perfusion fluid during initial donor heart arrest, poststorage graft reimplantation and early reperfusion. The major principles addressed by the Celsior formulation include (1) prevention of cell swelling (by mannitol and lactobionate), (2) prevention of by the Celsior formulation include (1) prevention of cell swelling (by mannitol and lactobionate), (2) prevention of oxygen-derived free radical injury (by reduced glutathione, histidine and mannitol), and (3) prevention of contracture by enhancement of energy production (glutamate) and limitation of calcium overload (high magnesium content, slight degree of acidosis). Two experimental preparations were used: The isolated isovolumic buffer-perfused rat heart model and the heterotopic rabbit heart transplantation model. In isolated heart experiments, hearts were arrested with and stored in Celsior for 5 h at 4 degrees C and subsequently reperfused for 1 h. A similar protocol was used in the transplantation experiments except that the total ischemic time was approximately 1 1/2 h longer (corresponding to 6 h of storage followed by the 25 additional minutes of cold ischemia required for graft implantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1994

Sequential resection of residual abdominal and thoracic masses after chemotherapy for metastatic non-seminomatous germ cell tumours.

Thirty-eight patients with advanced non-seminomatous germ cell tumours (NSGCTs) underwent multiple surgical interventions (two in 33 patients, three in four patients, four in one patient) after cisplatin-based chemotherapy. All patients had normal serum tumour markers but persistent radiographic masses. The larger mass was routinely resected first. Fifteen patients (39%) had dissimilar histological findings at sequential surgical procedures, 12 of whom demonstrated less favourable pathological features during the first operation and three at the second. Patients who underwent both retroperitoneal lymph node dissection (RPLND) and lung resection showed less favourable histological features in the retroperitoneum in nine cases and in the lung in three cases. Eight of 16 patients (50%) without mature teratoma in their primary tumours showed complete necrosis/fibrosis at all surgical interventions, whereas all patients whose primary tumour was classified as malignant teratoma intermediate demonstrated mature teratoma at least at one anatomical site. As histology of post-chemotherapy residual masses cannot be extrapolated from one anatomical site to another, patients usually are properly managed by excision of all residual masses. In particular, in patients with necrosis/fibrosis at lung resection omission of RPLND is not advised.

Abdominal Neoplasms↗
PubMed1994

[Hepatocellular carcinoma in pregnancy].

Primary hepatocellular carcinoma is a very rare disease, especially in association with a pregnancy. We report on a 22-year-old primigravida, who underwent Caesarean section in the 29th week of pregnancy in conjunction with tumour-reductive surgery for hepatocellular carcinoma. The further course of the disease was characterised by an early recurrence and lung metastases. Under palliative chemotherapy with 5-fluorouracil, the patient has been in a state of stable disease for several months. Typical risk factors for the hepatocellular carcinoma do not exist in the patient. Alternative explanations for the aetiology of the disease are discussed.

Adult↗