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Biomedical subjects

D Weiss

Publications and source records attributed to D Weiss.

At least 109 records · Page 6Linked to original sources
PubMed1987

A single bone marrow-derived stromal cell type supports the in vitro growth of early lymphoid and myeloid cells.

A clonal cell line (ALC) derived from murine bone marrow stroma is capable of supporting the continuous, in vitro growth of early lymphoid and myeloid cell populations. The growth-promoting effects of ALC are in part mediated through M-CSF and a pre-B cell growth factor, both of which accumulate in ALC-culture supernatant. To analyze the lymphoid growth factor produced by ALC cells, we derived a pre-B cell indicator line that is dependent on ALC-growth-conditioned medium. Using a combination of biological and biochemical analyses, we have established that the pre-B cell growth factor produced by ALC cells is distinct from IL-1, IL-2, IL-3, and IL-4 (BSF-1), suggesting that the early stages of B-cell development are regulated by a unique stroma-derived growth factor.

Animals↗
PubMed1987

The current evaluation of nonpalpable breast lesions.

To understand the suspected low yield of malignant neoplasms from biopsies guided by needle localization, we reviewed 122 biopsies performed from January 1985 to November 1986 at University Hospital and Arkansas Baptist Medical Center, Little Rock. The positive biopsy rates were 3.5% and 10.6%, respectively. After review of these cases, the following guidelines for biopsy were developed: (1) Do not perform a biopsy on a low-density mass less than 1 cm in diameter. (2) Do not perform a biopsy for asymmetric density or questionable mass. (3) Do not perform a biopsy for secondary signs of malignancy such as skin thickening or asymmetric vasculature. (4) Biopsy is indicated for clustered calcifications, a dominant mass greater than 1 cm in diameter, stellate lesions, or interval change from a previous mammogram. These changes resulted in a positive biopsy rate of 15% for the period from November 1986 through April 1987.

Biopsy, Needle↗
PubMed1987

Torsade de pointes complicating atrioventricular block: report of two cases.

One patient with complete atrioventricular heart block and another with high-degree atrioventricular block, complicated by "torsade de pointes" are presented. Both patients were symptomatic. One had a syncopal episode and the other presented with signs and symptoms of congestive heart failure. The electrocardiographic phenomena of torsade de pointes was repeatedly recorded. No other known predisposing factors for torsade de pointes were identified. The use of right ventricular endocardial pacing suppressed the paroxysms in both patients.

Aged↗
PubMed1987

The value of electrocardiography in patients with right ventricular endocardial pacemakers in the diagnosis of left ventricular hypertrophy: a correlative study of pace electrocardiography and left ventricular mass derived from M-mode echocardiography.

This study evaluated 51 patients with permanent apical right ventricular endocardial pacemakers. The assessment of the diagnostic value of pace electrocardiograms for the determination of left ventricular hypertrophy revealed specificity of 94% and sensitivity of 66%, applying a new parameter: RL1 + SV3 greater than or equal to 30 mm. The application of this criterion in the interpretation of pace electrocardiograms correlated well with values for the left ventricular mass derived from M-mode echocardiograms (r = 0.644, P less than 0.0001).

Aged↗
PubMed1987

Transient complete atrioventricular dissociation and asystole following junctional premature beats in a patient with acute myocardial infarction.

A 58-year-old patient is presented with recurrent episodes of complete atrioventricular dissociation and asystole which followed junctional premature beats during the acute phase of myocardial infarction. This uncommon electrocardiographic phenomenon occurred when junctional premature beats interfered with the conduction in a previously compromised atrioventricular node, leading to the above-mentioned electrocardiographic phenomenon.

Arrhythmias, Cardiac↗
PubMed1987

Atrioventricular block complicating dissecting aneurysm of the aorta.

A 67-year-old patient who presented with acute dissecting aneurysm of the aorta was complicated by progressive transient atrioventricular heart block. Post-mortem examination findings confirmed the diagnosis of dissection of the ascending aorta and revealed an interatrial haemorrhage in the area of the septal atrioventricular junction.

Aged↗
PubMed1987

Pacemaker Twiddler's syndrome.

The pacemaker Twiddler's syndrome was recognized in a patient who presented with dizziness due to failure of his recently implanted endomyocardial permanent pacemaker system. Electrocardiographic, X-ray and intraoperative findings are presented.

Aged↗
PubMed1987

USAID in Nepal.

Explore the source record for details and available documents.

Agriculture↗
PubMed1986

Ciprofloxacin: a comparative evaluation of its bactericidal activity in human serum against four enterobacterial species.

Serum bactericidal titres following a 200 mg i.v. dose of ciprofloxacin were measured in healthy volunteers and compared with those achieved with standard doses of ceftazidime, piperacillin and gentamicin, given alone or in combination. Five strains of each of four enterobacterial species were included in the study. Bactericidal titres 1 h after infusion of ciprofloxacin exceeded 1:16 for Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris and Enterobacter cloacae. While ceftazidime produced higher peak bactericidal titres against the Enterobacteriaceae, piperacillin was less effective than ciprofloxacin against three of the four enterobacterial species tested. Among the combinations, only piperacillin/gentamicin showed synergistic activity against some strains. Studies of bacterial killing kinetics again confirmed the high bactericidal activity of ciprofloxacin for the Enterobacteriaceae. The combination of ciprofloxacin with gentamicin resulted in more rapid killing of some strains of Klebsiella pneumoniae and Proteus vulgaris.

Adult↗
PubMed1985

Neoplastic pathology of oncogenic osteomalacia/rickets.

Reported are two cases of oncogenic osteomalacia, each caused by a small mesenchymal tumor, with detailed assessment of the tumors by light microscopy, electron microscopy, and immunohistochemistry. One tumor was a primitive mesenchymal tumor with prominent giant cell and vascular components, and the second resembled the giant cell variant of soft parts chondroma. Osteoclast-like, multinucleated giant cells and vascularity were prominent features in both tumors. Although the literature documents a histologically heterogeneous group of tumors as causing this syndrome, most have multinucleated giant cells and/or extensive vascularity. The high incidence of these two histologic features in this group of tumors suggests that either or both may be related to the pathogenesis and/or metabolic consequences of oncogenic osteomalacia/rickets.

Adult↗
PubMed1985

Oncogenic osteomalacia: strange tumours in strange places.

Two patients presented with hypophosphataemic osteomalacia and were subsequently found to have small tumours unusual histopathology and location causing the osteomalacia. Each tumour was found after an intensive search for occult masses. Studies of vitamin D metabolism and renal tubular function before and after surgery yielded further insight into the pathophysiology of oncogenic osteomalacia. These cases demonstrate that microscopic quantities of tumour are capable of causing the syndrome and further illustrate the high index of suspicion often necessary to locate causative tumours in patients with hypophosphataemic osteomalacia.

Adult↗
PubMed1985

[Computer management of the data of automated perimetry using Octopus 2000 R].

Current perimetry involves automated, static and punctual procedures, which permit the examiner to obtain a numerical value of the sensibility concerning the points tested. Besides its precision and its reliability, perimetry can be used in data processing management due to the characteristic of easy duplication of the examinations. We use a micro-computer which is seperate from the Octopus 2000 R (Apple IIc) and the disc (OmnisII) to process the files. The study is composed of the following areas: the storage and the data processing of patient files, the transformation of numerical data a graphics display, the study of the percentage of loss of surface according to the decibel of sensibility. The data processing of files improves storage according to the criteria defined by the examiner and helps avoid inconvienent research. The graphic transformation of numerical data into isopteres of chosen sensibility improves the definition of the zones of intermediate sensibility. The calculations of the percentage of loss of surface according to the decibel of sensibility allows the appreciation of the size of defects based on depth and quantification. It is also easy to make the comparison between the two fields.

Aphakia, Postcataract↗
PubMed1984

[Cricopharyngeal achalasia in stroke patients].

A 68-year-old man developed severe swallowing difficulties after a cerebrovascular accident: he was unable to take food. Nutrition was assured via a gastrostomy ( Witzel fistula). Nonetheless there was steady weight loss. A cricopharyngeal achalasia was finally discovered to be the cause of the swallowing problem. Myotomy of the cricopharyngeal muscle completely abolished it.

Aged↗
PubMed1984

Prognosis after sudden cardiac death without associated myocardial infarction: one year follow-up of empiric therapy with amiodarone.

Thirty-three consecutively referred patients with cardiac arrest from ventricular arrhythmias unassociated with a new acute myocardial infarction (AMI) were commenced on amiodarone therapy and followed for a minimum of 12 months. The dose of amiodarone was adjusted to maximum tolerance and not according to the incidence of asymptomatic ventricular premature complex activity. Eight patients died including five sudden deaths. Five out of the eight deaths occurred either within 3 months of therapy or when the dose of amiodarone was less than 400 mg/day. The majority of patients were found to have corneal microdeposits or either thyroid or liver function abnormalities, although none had any clinical manifestation. Ten patients had neurologic side effects. In summary, although the overall cardiac mortality seemed to be reduced by amiodarone therapy and the drug appears to be well tolerated by patients, its role in the prophylaxis against recurrent ventricular fibrillation may be enhanced by a regimen of higher loading and maintenance doses.

Adult↗
PubMed1983

Evaluation of amiodarone therapy in the treatment of drug-resistant cardiac arrhythmias: long-term follow-up.

The clinical efficacy of amiodarone in the management of complex cardiac arrhythmias refractory to therapy with two or more conventional or other investigational antiarrhythmic agents was determined by long-term follow-up in patients who had received the drug for at least 3 months. A total of 181 patients, classified into four groups (group 1, supraventricular arrhythmias, n = 42; group 2, frequent ventricular premature complexes, n = 46; group 3, nonsustained ventricular tachycardia, n = 16; and group 4, sustained ventricular tachycardia, n = 77) received a daily maintenance dose of 200 to 800 mg amiodarone for up to 30 months. There was a total of 26 deaths (14%). Ten of these were probably attributable to arrhythmia, although all patients had either good or excellent response to therapy over a mean follow-up of 14.9 months prior to death. The drug had to be permanently discontinued because of side effects in only three patients, and in the majority of patients with side effects, symptoms could be alleviated with adjustment of dosage, thyroid replacement therapy, or temporary cessation of therapy. We conclude that amiodarone is highly effective in high-risk patients with complex refractory cardiac arrhythmias, and that close monitoring and prompt recognition of side effects and appropriate adjustment of dosage or institution of supplemental or replacement therapy (in less than 5% of patients) will allow continuation of amiodarone. The benefit of suppression of symptomatic arrhythmias and the potential of prevention of sudden death clearly outweigh the modest incidence of severe side effects.

Aged↗
PubMed1983

The efficacy of Ajmaline in ventricular arrhythmias after failure of lidocaine therapy in the acute phase of myocardial infarction.

Forty-three patients in the acute phase of myocardial infarction who were resistant to conventional doses of lidocaine received Ajmaline intravenously (50 mg bolus followed by constant infusion rate of 1-1.5 mg/min). Dangerous ventricular arrhythmias were abolished in 72% of this group of patients (group A). In the remaining patients (28%), Ajmaline was found to be ineffective (group B). There was no reduction of systolic or diastolic blood pressure and there was an insignificant increase in heart rate. Atrio-ventricular or intraventricular conduction defects appeared in 46% of the patients described. There was a statistically significant increase in occurrence of heart blocks in group B patients and among these complete left bundle branch block (CLBBB) was the most prevalent. Atrio-ventricular or intraventricular conduction defects were transient, appearing between 8-36 h (mean 23 h), and were not accompanied by reduction of ventricular rate. Conduction defects disappeared within several hours (up to 24 hours) after Ajmaline was discontinued. It is concluded that Ajmaline administered by this regimen is an effective alternative agent for patients with ventricular arrhythmia not controlled by lidocaine in the acute phase of myocardial infarction.

Ajmaline↗