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Biomedical subjects

J Brown

Publications and source records attributed to J Brown.

At least 937 records · Page 52Linked to original sources
PubMed1984

Angiotensin II receptors in chromatin.

When isolated rat hepatic nuclei or bovine thymus nuclei were incubated with 125I-angiotensin II (ANG II) in the presence or absence of cold hormone, displaceable binding was consistently detected in micrococcal nuclease generated fragments Nanomolar concentrations of ANG II produced detectable displacement. Little or no specific binding was found when nuclei were first digested and then treated with hormone, suggesting that ANG II solubilizes its own receptor. The binding moiety was partially purified by DNP gel electrophoresis. These studies indicate the existence in chromatin of high affinity receptors for ANG II, and further suggest that hormone binding to these receptors produces conformational changes in chromatin similar to those seen during enhanced transcriptional activity. Thus, the present studies suggest the existence of functional intracellular renin-angiotensin systems.

Angiotensin II↗
PubMed1984

Effect of cysteamine on secretion of gastrin and somatostatin from the rat stomach.

Cysteamine (beta-mercaptoethylamine HCl) administration to rats induces a hypergastrinemia and a reduction in gastric tissue somatostatin content. The possibility that this reduction may contribute to the elevated gastrin levels has been investigated in the isolated perfused rat stomach. Cysteamine (1 mM) rapidly increased immunoreactive gastrin release to levels ranging between 41% and 125% above basal. Increasing the dose to 10 mM caused a 1148% increase in immunoreactive gastrin. Secretion of somatostatinlike immunoreactivity did not change. Perfusion of gastric inhibitory polypeptide (1 nM) induced a sustained increase in somatostatinlike immunoreactivity secretion and a transient rise in gastrin. Addition of 10 mM cysteamine during gastric inhibitory polypeptide perfusion caused a 300% increase in immunoreactive gastrin. These levels were lower than in response to cysteamine alone. The results demonstrate that cysteamine can stimulate immunoreactive gastrin secretion without any change in somatostatinlike immunoreactivity release. When somatostatinlike immunoreactivity secretion is stimulated by an agent such as gastric inhibitory polypeptide, the cysteamine-induced release of immunoreactive gastrin is attenuated, suggesting the presence of a functional linkage between somatostatin and gastrin under these conditions.

Animals↗
PubMed1984

Multifocal pyomyositis. Diagnosis on technetium-99m MDP bone scan.

Pyomyositis is a bacterial infection of skeletal muscle occurring in the absence of trauma or a primary site of infection. The condition is rare in temperate climates. The diagnosis is often difficult to make and frequently delayed since the suppurative process is confined by the tense overlying muscle and fascia. The bone scan is very useful in differentiating underlying osteomyelitis and septic arthritis. An 11-year-old boy is described who presented with multifocal pyomyositis in the elbow region and thigh. Lateral blood pool images suggested infection with liquefaction within the muscles without evidence of osteomyelitis.

Bone and Bones↗
PubMed1984

Cardiac arrhythmias. Diagnosis and treatment.

Arrhythmias arise from a wide range of cardiac pathology and their assessment requires an appreciation of the underlying disorder. The urgency of therapeutic intervention depends on how severely cardiac output and blood pressure are affected. Treatment ranges from reassurance, to drug therapy, pacemaker implantation and occasionally cardiac surgery.

Arrhythmia, Sinus↗
PubMed1984

Antagonism of xylazine sedation in steers by doxapram and 4-aminopyridine.

Five groups of 6 fasted crossbred steers were injected IM with standard dosages of xylazine hydrochloride (0.3 to 0.5 mg/kg). At maximal sedation, the steers were injected IV with the antagonists' doxapram (1.0 mg/kg), doxapram + yohimbine (0.125 mg of yohimbine/kg), doxapram + 4-aminopyridine (4-AP; 0.3 mg of 4-AP/kg), or 4-AP + yohimbine. One group was given 1.0 ml of saline solution IV instead of antagonists. Doxapram, doxapram + yohimbine, doxapram + 4-AP, and 4-AP + yohimbine decreased mean standing time (time from antagonist injection until animal could stand unaided) to 17.0, 4.3, 3.3, and 4.5 minutes, respectively--significantly (P less than 0.05) down from a control value of 49.8 minutes. Mean total recovery time (time from xylazine injection until animal resumed eating) was decreased to 78 minutes by doxapram and 81.6 minutes by doxapram + 4-AP--significantly (P less than 0.05) down from the control value of 142.9 minutes. Respiratory character was improved (depth of respiration was increased) only by doxapram + 4-AP. Relapses to recumbency and marked sedation were not seen in steers given doxapram + 4-AP or the saline solution. One steer given doxapram, 2 given doxapram + yohimbine, and 1 given 4-AP + yohimbine relapsed to recumbency and sedation. Recovery was relatively smooth in steers given doxapram + 4-AP or 4-AP + yohimbine. Animals given doxapram or doxapram + yohimbine had difficult recoveries.(ABSTRACT TRUNCATED AT 250 WORDS)

4-Aminopyridine↗
PubMed1983

Hyperthermic adjuvant perfusion chemotherapy for Stage I malignant melanoma of the extremity with literature review.

Thirty-nine patients with clinical Stage I malignant melanoma of the extremities were treated with hyperthermic perfusion chemotherapy using melphalan followed by excision or wide re-excision of the area and regional lymph node dissection. Four patients with positive lymph nodes, on histologic examination, were considered pathologic Stage II. Seventy-two patients with clinical Stage I extremity melanomas, who were treated by conventional surgical methods, served as concurrent controls, and were comparable in the distribution of their various pretreatment characteristics. The actuarial survivals for clinical Stage I perfusion patients calculated by the life-table method at 5, 10, and 15 years were 91%, 86%, and 77%, respectively, and disease-free survivals were 85%, 80%, and 80%, respectively. These figures were significantly better than controls. A Breslow depth of invasion of greater than 1.5 mm showed a significant difference in both clinical and pathologic Stage I disease as compared with the controls. Similarly, perfused patients aged less than or equal to 50 years survived significantly better than controls in both clinical and pathologic Stage I disease. The literature has been reviewed.

Chemotherapy, Cancer, Regional Perfusion↗
PubMed1983

Purification and properties of a pantetheine-hydrolyzing enzyme from pig kidney.

A microsomal glycoprotein that catalyzes the hydrolysis of pantetheine to pantothenate and cysteamine was solubilized and purified to homogeneity as determined by sodium dodecyl sulfate electrophoresis. The enzyme from pig kidney cortex was solubilized on exposure to butanol and purified by heat treatment, ammonium sulfate fractionation, hydrophobic chromatography, and hydroxyapatite chromatography. The purified enzyme (Mr = 57,000) has a specific activity of 14 mumol of pantothenate produced per min/mg of protein, a value 35 times that previously reported. A method for localizing enzymatic activity on polyacrylamide gels is presented, and enzyme activity, protein, and carbohydrate are shown to migrate identically by electrophoresis on nondenaturing polyacrylamide gels. Amino acid analysis indicated an absorbance index E1%1cm (280 nm) of 11.3, and carbohydrate analysis revealed the presence of galactose, mannose, fucose, glucose, galactosamine, and sialic acid for a total carbohydrate composition of 11.8%. The enzymatic hydrolysis of various pantetheine analogs indicated the enzyme had a high specificity for the pantothenate moiety but a low specificity for the cysteamine portion.

Amino Acids↗
PubMed1983

Effects of lorazepam on rate of forgetting, on retrieval from semantic memory and on manual dexterity.

Using a double-blind procedure, 16 out of 32 volunteer subjects (students) each took 2.5 mg of lorazepam (Ativan) orally and the remainder took a placebo. To overcome the problem of wide variation in individual tolerance to the drug, impairment on a task unrelated to memory (a manual dexterity task) was used to divide drug subjects into a group appreciably affected by the drug, subgroup 1, and a group minimally affected, subgroup 2. Only subgroup 1 showed consistent impairment of episodic memory. Both subgroups showed some impairment in a semantic memory task (generation of words from a specified category), but this was confined to the rate at which the task was carried out. The main aim of the experiment was to examine the effect of lorazepam on the rate of forgetting of word lists when drug and control subjects' initial recall levels were equalized. There was no evidence that the drug affected rate of forgetting: this suggests that it does not affect retention. There was also no evidence that it affected retrieval, since there was no impairment in the recall of material presented before administration of the drug. Hence its locus of action is attributed to input, specifically to impaired encoding of contextual information.

Adult↗
PubMed1983

In vivo assessment of 99mTc-labeled hematoporphyrin derivative in tumor-bearing animals.

The efficacy of 99mTc-labeled hematoporphyrin derivative in localizing neoplasms has been investigated with tumor-bearing animal models. Spontaneous mammary adenocarcinomas of outbred CFW strain Swiss-Webster white mice and chemical carcinogen induced breast tumors in female Sprague-Dawley white rats were clearly visualized in the scintigrams. Mice tissue distribution data demonstrate favourable tumor to organ ratios sufficiently high to permit tumor detection. [99mTc]HPD appears promising as a tumor imaging agent.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1983

Spermagglutinins in serum and seminal fluid of bulls and their relationship to fertility classification.

Twenty-five satisfactory and 25 unsatisfactory potential breeder bulls were examined with a modified Shulman spermagglutination test for the presence of spermagglutinating antibodies in their serum and seminal fluid. This was done to determine whether antibodies to spermatozoa were a contributing factor to classification of the bull as an unsatisfactory potential breeder. No correlation was found between classification as an unsatisfactory potential breeder and the presence of spermagglutinating antibodies. In addition, indirect fluorescent antibody tests were performed to detect antisperm antibodies in the serum and seminal fluid of the bulls. Again, no correlation was found between antisperm antibodies and breeding soundness classification. Finally, there was no correlation between the age of the bulls and occurrences of spermagglutination antibodies in serum or seminal fluid.

Journal Article↗
PubMed1983

Clinical and hemodynamic follow-up of left ventricular to aortic conduits in patients with aortic stenosis.

To assess the long-term results of left ventricular outflow tract reconstruction utilizing an apical left ventricular to aortic valved (porcine) conduit the clinical and hemodynamic data were reviewed from 24 patients who had placement of an apico-aortic conduit. Eighteen of the patients are asymptomatic and taking no cardiac medications. Three patients were reoperated on, one patient 1.5 years after his original operation for subacute bacterial endocarditis and two patients 3 to 4 years after their original operation for severe conduit valve insufficiency. None of the patients is taking anticoagulants and no thromboembolic events have occurred. Postoperative catheterization has been performed 1 to 1.5 years (mean 1.2) after repair in 15 of 21 patients. The rest left ventricular outflow tract gradient has decreased from 102.5 +/- 20 mm Hg preoperatively to 14.8 +/- 9.9 mm Hg postoperatively (probability [p] less than 0.001). Some degree of conduit obstruction was demonstrated by catheter passage in 11 of the 15 patients. In these 11 patients, the obstruction occurred at three distant sites: at the egress of the left ventricle in 9, at the porcine valve in 5 and at the aortic to conduit junction in 1. Isometric exercise in five and supine bicycle exercise in six patients increased the left ventricular outflow tract gradient by 2.5 +/- 1.1 and 20.8 +/- 11.8 mm Hg, respectively, despite an increase in cardiac index of 1 +/- 0.3 and 3.7 +/- 0.4 liters/min per m2, respectively. The data suggest that a left ventricular to aortic conduit is an effective form of therapy for severe left ventricular outflow tract obstruction.

Adolescent↗