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Biomedical subjects

E Benjamin

Publications and source records attributed to E Benjamin.

At least 73 records · Page 4Linked to original sources
PubMed1986

Adrenergic and serotonergic receptor responsiveness in depression.

Preliminary results are presented from a series of studies designed to characterize the regulation of release/metabolism and receptor responsiveness in the noradrenergic and serotonergic systems in acutely depressed patients and depressed patients in remission. Abnormal regulation of noradrenaline release/metabolism might be expected to be associated with the acute state of depression, while abnormalities of adrenoceptor responsiveness were hypothesized to persist in remission. Growth hormone responses to clonidine were measured as indices partially reflecting alpha 2-adrenoceptor responsiveness. Blunted responses to clonidine were found in both acutely depressed patients and patients in remission. The possible implications of these findings for the pathophysiology of the noradrenergic system in depression are discussed. Prolactin responses to the serotonergic agonist and serotonin-releasing agent fenfluramine were evaluated in acutely depressed patients, patients in remission and controls. A subset of the depressed patients appeared to have blunted prolactin responses to fenfluramine. However, very preliminary results do not show any difference in this response between patients who were acutely ill and those in remission, although the variability in both groups was great. These and related findings are discussed in terms of a possible contributory role of the serotonergic system in depression.

Clonidine↗
PubMed1986

Intranasal delivery of nicardipine in the rat.

The intranasal absorption of nicardipine hydrochloride was characterized in an in vivo rat model system in which the normal mechanisms of mucociliary clearance and drainage of an instilled dose were not physically altered. The results obtained in this manner, therefore, are expected to be predicative of the delivery and absorption dynamics exhibited in the nasal mucosa of primates and humans. Intranasal delivery of nicardipine was studied in male rats using this model on single-dose administration of 1.0 mg/kg, and compared with both oral and intravenous administration. The effect of the addition of a viscosity agent, hydroxyethyl cellulose, on plasma levels following nasal delivery was also examined. Nicardipine plasma levels were determined by a rapid and specific reversed-phase HPLC method with electrochemical detection that employed nifedipine as an electroactive internal standard in the analysis. The limit of quantitation for nicardipine at 1.0 V versus Ag/AgCl was 8 ng/mL and the linear dynamic range was 15-150 ng/mL. Following intravenous administration the area under the plasma concentration curve was 5110 ng . min/mL as compared to 3730 ng . min/mL following intranasal dosing. This corresponds to a bioavailability of 73%. The addition of a viscosity agent to the nasal formulation was found to give a slight but statistically insignificant increase in the systemic availability (77%). Plasma levels of nicardipine following oral administration (1.0 mg/kg) were determined to be below the limit of quantitation of the analytical technique. These results therefore suggest that nasal delivery of nicardipine is a viable and efficient route of administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intranasal↗
PubMed1986

Thrombocytopenia following peritonitis in surgical patients. A prospective study.

Thrombocytopenia is commonly found in patients with serious infection. To investigate this phenomenon, 14 consecutive patients (68 +/- 10 years) who underwent laparotomy for bowel perforation and culture-proven peritonitis were prospectively studied. Ten noninfected laparotomy patients served as a control group. None of the 10 control patients developed thrombocytopenia. Of the infected group, 12 of 14 patients (85%) developed thrombocytopenia (less than 100,000/mm3). One patient (9%) developed disseminated intravascular coagulation (DIC). Of the remaining 11 patients with thrombocytopenia, platelet counts fell from preoperative level of 350,000 +/- 166,000 to 54,000 +/- 30,000 (p less than 0.001) and reached this nadir 4.3 +/- 2 days after surgery. There was no statistically significant difference in prothrombin time, partial thromboplastin time, or fibrinogen levels before versus after operation in this group. Bleeding times in seven patients were 5.5 +/- 2 minutes, and bone marrow examination in five patients with platelet counts of less than 50,000/mm3 revealed normal or increased megakaryocytes. No patient in this group bled, had medications held, or received platelet transfusions. Platelet counts increased greater than 100,000/mm3 at a mean of 8.9 +/- 4.1 days after operation. It is concluded that thrombocytopenia is common following surgery for intra-abdominal infection, is not usually associated with DIC, clinical bleeding, or coagulation abnormalities, does not commonly result from bone marrow suppression, and is transient and does not require routine platelet transfusions.

Disseminated Intravascular Coagulation↗
PubMed1986

Use of constant-infusion verapamil for the treatment of postoperative supraventricular tachycardia.

The effects of constant-infusion verapamil were studied in ten postoperative ICU patients who developed supraventricular tachycardia (atrial fibrillation) with rapid ventricular response rates. A 5-mg iv bolus dose of verapamil was followed by a 5-mg/h infusion that continued for 8 h. Ventricular rates were significantly (p less than .005) reduced from a pretreatment mean of 156 +/- 14 (SD) to 104 +/- 9 beat/min on constant-infusion therapy. This therapy was well tolerated without observed side-effects. Moreover, constant-infusion verapamil might avoid the hypotension and wide range of ventricular rates frequently encountered with repeated bolus doses of verapamil.

Aged↗
PubMed1985

Ventricular arrhythmias during pulmonary artery catheterization in the intensive care unit. Prospective study.

The balloon-tipped, flotation pulmonary artery catheter is frequently utilized in the management of intensive care unit patients. Advanced ventricular arrhythmias (three or more consecutive premature ventricular contractions) have been reported in 25 to 68 percent of intensive care unit patients undergoing catheterizations. A group of 56 intensive care unit patients who received a pulmonary artery catheter were prospectively studied to determine the incidence of catheter-induced arrhythmias and the time required for catheterization. The mean age of the patients was 69.8 +/- 11 years. Indications for catheterization included septic shock (n = 10), congestive heart failure (n = 8), hypovolemia (n = 12), respiratory failure (n = 2), preoperative cardiac evaluation (n = 20), and miscellaneous (n = 4). Advanced ventricular arrhythmias were recorded in seven of the 56 patients (12.5 percent), the longest arrhythmia being a run of seven consecutive premature ventricular contractions. No patient required treatment with lidocaine for their arrhythmias and all arrhythmias resolved with catheter movement. The mean time of catheterization for the 56 patients was 175.9 seconds (SD 263.2), and was not significantly different for patients with or without arrhythmias. There was no statistical difference in catheterization times or incidence of arrhythmias between critically ill patients and the preoperative patients. It is concluded that pulmonary artery catheterization can be performed in critically ill patients with a lower incidence of arrhythmias than has previously been reported. The decreased incidence of arrhythmias may be secondary to the decreased catheterization times.

Aged↗
PubMed1985

Hemodynamic effects of verapamil in the beta-blocked dog.

The use of the calcium channel-blocking agent, verapamil, in beta-blocked patients has been the subject of intense investigation, particularly because both verapamil and the beta-blockers can produce negative inotropic effects. We studied the hemodynamic effects of verapamil in beta-blocked dogs to establish specific measurements that could be used clinically for early identification of combined negative inotropism. Seven anesthetized, mongrel dogs were beta-blocked with propranolol, and then given 2.5-, 5.0-, and 10.0-mg iv boluses of verapamil. The 2.5- and 5.0-mg boluses represent clinical doses, whereas the 10.0-mg bolus is a large pharmacologic dose. Hemodynamic measurements showed that verapamil was well tolerated at clinical doses; increases in stroke volume compensated for decreases in mean arterial pressure. At high doses of verapamil this response was not observed and left ventricular stroke work decreased. Cardiac and stroke indices were not useful indicators of combined drug toxicity in this dog model.

Animals↗
PubMed1984

Relationship between intake and rate of oxidation of leucine and alpha-ketoisocaproate in vivo in the rat.

Rates of oxidation of leucine by rats fed, ad libitum, diets containing graded amounts (0-2.4%) of leucine together with L-[1-14C]leucine were measured for 12 hours. The amount of leucine oxidized was low until dietary leucine content exceeded that needed for maximum rate of weight gain. Thereafter, the rate of leucine oxidation increased essentially linearly with increasing dietary leucine content. Rates of oxidation of alpha-ketoisocaproic acid (KIC) by rats fed, ad libitum, diets devoid of leucine to which graded amounts (0-2.05%) of KIC were added together with [1-14C]KIC were also measured for 12 hours. The amount of KIC oxidized increased as dietary KIC content oxidation studies plasma valine and alpha-ketoisovaleric acid (KIV) and plasma isoleucine and alpha-keto-beta-methylvaleric acid (KMV) concentrations were depressed when dietary levels of leucine were high. Plasma leucine and KIC concentrations were low when dietary levels of leucine were low and increased with increasing dietary leucine content. Leucine and KIC concentrations in plasma of rats fed a diet devoid of leucine did not increase in proportion to increasing dietary KIC content.

Amino Acids, Branched-Chain↗
PubMed1984

Adult onset idiopathic familial brain calcifications.

We treated a family with idiopathic calcifications of symmetric areas of the brain, including the basal ganglia, dentate, and cerebral white matter. Dementia, progressive dysarthria, incontinence, propulsive-ataxic gait, fixed facies, and cogwheel rigidity without dysmorphic features develop in affected persons. Calcium, phosphorus, and parathyroid hormone levels were normal in the two siblings tested. The literature is reviewed and five other families with a similar syndrome are identified. These six families seem to be clinically distinct from the larger group of idiopathic cerebral calcifications usually referred to as Fahr's disease.

Adult↗
PubMed1982

Malignant fibrous histiocytomas of salivary glands.

The light microscopic, immunohistological and ultrastructural findings in two cases of malignant fibrous histiocytoma arising in salivary glands are presented and the features of seven previously reported cases are reviewed. This neoplasm is extremely rare in this site and may pose problems in diagnosis. It has to be distinguished from other spindled cell tumours, in particular from epithelial tumours of predominantly spindled cell pattern; immunohistological markers for histiocytic cells may be of value. The histogenesis of this neoplasm is controversial but our electron microscopic findings support an origin from mesenchymal cells which differentiate along a broad fibrohistiocytic spectrum.

Adult↗
PubMed1981

Hepatoblastoma as a cause of intrauterine fetal death. Case report.

A hepatoblastoma was found in a 36 week stillborn infant. The tumour compressed the inferior vena cava and was the cause of hydrops foetalis. There was also agenesis of the gall bladder. Amniotic fluid alpha-fetoprotein levels at 15 weeks were normal and did not indicate the presence of the tumour.

Carcinoma, Hepatocellular↗
PubMed1981

Malakoplakia of the adrenal gland.

The clinical and pathological features of a case of malakoplakia of the adrenal gland occurring in a woman with Escherichia coli infection are described. This lesion mimicked a neoplasm, the true diagnosis only being revealed by histological examination. The light and electron microscopic features are described and it is suggested that malakoplakia is due to an abnormal macrophage response to E coli infection.

Adrenal Gland Diseases↗