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Biomedical subjects

J S Martin

Publications and source records attributed to J S Martin.

At least 73 records · Page 4Linked to original sources
PubMed1990

Early recognition and treatment of the patient suffering from acute myocardial infarction. A description of the Myocardial Infarction Triage and Intervention Project.

Involving emergency medical personnel in the evaluation and treatment of the AMI patients is feasible. A standard, organized approach saves time. Obtaining an ECG in the prehospital setting is also feasible and decreases the delay to diagnosis and subsequent treatment for patients after hospital arrival. Early findings from the MITI registry suggests that only 20% to 30% of patients with AMI are currently eligible to receive thrombolytic medications. This seems to indicate that either current treatment guidelines need to be broadened or that thrombolytic therapy is not appropriate for all AMI patients and, therefore, alternative acute treatment approaches need to be investigated further.

Humans↗
PubMed1988

Use of the automatic external defibrillator in the management of out-of-hospital cardiac arrest.

The automatic external defibrillator is a simple device that can be used by nonprofessional rescuers to treat cardiac arrest. In 1287 consecutive patients with out-of-hospital cardiac arrest, we assessed the results of initial treatment with this device by firefighters who arrived first at the scene, as compared with the results of standard defibrillation administered by paramedics who arrived slightly after the firefighters. Of 276 patients who were initially treated by firefighters using the automatic defibrillator, 84 (30 percent) survived to hospital discharge (expected rate according to a logistic model, 17 percent; P less than 0.001), as compared with 44 (19 percent) of 228 patients when fire-fighters delivered only basic cardiopulmonary resuscitation and the first defibrillation was performed after the arrival of the paramedic team. Few patients with conditions other than ventricular fibrillation survived. In a multivariate analysis of characteristics that influenced survival after ventricular fibrillation, a better survival rate was related to a witnessed collapse (odds ratio, 3.9; 95 percent confidence interval, 2.0 to 7.6), younger age (odds ratio, 1.2; 95 percent confidence interval, 1.0 to 1.4), the presence of "coarse" (higher-amplitude) fibrillation (odds ratio, 4.2; 95 percent confidence interval, 1.6 to 11.0), a shorter response time for paramedics (odds ratio, 1.4; 95 percent confidence interval, 1.0 to 2.1), and initial treatment by firefighters using an automatic external defibrillator (odds ratio, 1.8; 95 percent confidence interval, 1.1 to 2.9). These findings support the widespread use of the automatic external defibrillator as an important part of the treatment of out-of-hospital cardiac arrest, although the overall impact of the use of this device on community survival rates is still uncertain.

Aged↗
PubMed1988

Daily variability in human serum prostate-specific antigen and prostatic acid phosphatase: a comparative evaluation.

The daily variation of serum levels of prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) was investigated simultaneously in 10 patients with osseous metastatic prostatic cancer, 10 patients with benign prostatic hyperplasia, and 10 volunteers without prostatic disease. Duplicate serum samples were obtained from all patients on the same day at 8 AM, 12 PM, 4 PM, and 8 PM. Statistical analysis (two-factor analysis of variance comparing time period to disease group) of the mean PSA and PAP levels at the four sampling times on all patient groups demonstrated no evidence of circadian rhythmic variation or any other distinct pattern for the observed sample times. Overall, the variability in PSA levels was significantly less than that observed for PAP. There was no significant difference in mean percent variation between patient groups (cancer, benign, and normal prostate glands) for both the PSA and PAP assays. Our data reveal that serum PSA measurements fluctuate unpredictably over the course of a day in patients with and without prostatic disease, but to a lesser extent than that seen for serum PAP values. These findings illustrate the potential inaccuracy of single determinations of serum PAP or PSA levels for monitoring disease recurrence and treatment response in patients with prostate cancer.

Acid Phosphatase↗
PubMed1986

Comparison of the inhibitory effects of spermine, papaverine and adrenaline upon isolated segments of the rat small intestine.

In the rat isolated duodenal and ileal segments the active baseline force and spontaneous contractile frequency were inhibited by spermine; the relative potencies, estimated as an ED50, were adrenaline papaverine spermine. The changes in baseline force, but not frequency, due to spermine were sensitive to increased calcium. The duodenum was always more sensitive to papaverine and adrenaline, but the relative sensitivities of the duodenum and ileum were essentially equal for spermine. Inasmuch as the gastrointestinal mucosa of most species contains an abundance of polyamines, these results suggest that, in its free form, spermine may subserve a functional role in the inhibition of gastrointestinal motility.

Animals↗
PubMed1982

Unifocal eosinophilic granuloma of the temporal lobe.

The clinical features, treatment, and two-year postoperative course of a 14-year-old boy with unifocal eosinophilic granuloma of the temporal lobe are presented. A literature review of unifocal eosinophilic granuloma of the brain revealed 11 additional cases, 9 of which involved the hypothalamus and 1 each the frontal and temporal lobes. Four of the 9 patients with involvement of the hypothalamus developed multifocal disease, whereas none of the 3 who had frontal or temporal lobe involvement developed multifocal lesions. Effective therapy for eosinophilic granuloma in a single resectable site in the brain appears to be total excision. Low-dose radiation has been used to eradicate locally recurrent disease.

Adolescent↗
PubMed1982

Adrenergic control of somatostatin release.

The effects of adrenergic stimulation and suppression on somatostatin (SS), insulin, and glucagon release were studied in intact dogs. Isoproterenol, a beta-adrenergic agonist, significantly increased portal venous and arterial levels of SS and arterial levels of insulin and glucagon. Propranolol, a beta-adrenergic antagonist, significantly decreased portal venous SS and suppressed the isoproterenol-stimulated increases in the levels of SS, insulin, and glucagon. alpha-Adrenergic stimulation (propranolol plus epinephrine) decreased portal venous SS and arterial insulin. Phentolamine, and alpha-adrenergic antagonist, increased portal venous and arterial SS and arterial glucagon. These data suggest that in intact dogs, stimulation of beta-adrenergic receptors enhances the release of SS, insulin, and glucagon, while stimulation of alpha-adrenergic receptors inhibits the release of SS and insulin without having a definitive effect on glucagon.

Animals↗
PubMed1982

Absence of an effect of terfenadine on guinea pig brain histamine H1-receptors in vivo determined by receptor binding techniques.

Alpha-[4-(1,1-Dimethylethyl)phenyl]-4-(hydroxydiphenylmethyl)-1- piperidinebutanol (terfenadine, RMI 9918, Triludan, Teldane, resp.) inhibition of the in vitro binding of [3H]mepyramine to histamine H1-receptors prepared from guinea pig brain and ileum was characterized under several experimental conditions. After an intraperitoneal injection of 5 mg/kg of either terfenadine or chlorpheniramine, brain and ileum were obtained to determine in vitro the binding of [3H]mepyramine to histamine H1-receptors. While the binding of ligand to receptors from the ileum of both terfenadine and chlorpheniramine treated animals was almost completely inhibited, the ligand binding to receptors from brains of chlorpheniramine treated but not terfenadine treated animals was affected. When terfenadine was added to receptor homogenates from guinea pig brain and ileum, it antagonized the binding of [3H]mepyramine to receptors from both tissues. The potency of terfenadine antagonism of ligand binding was similar to both ileal (IC50, 200 nmol/l) and brain (IC50, 300 nmol/l) receptors. The kinetics of in vitro antagonism by terfenadine of [3H]mepyramine binding to receptors is unique in that antagonism of ligand binding by terfenadine was enhanced by a longer incubation of the receptors with this drug and H1-receptor blockade by terfenadine could not be reversed by extensive washing of these receptors at 25 degrees C. These results show that terfenadine treatment does not result in sufficient levels in the brain to inhibit central histamine receptors at a dose which overwhelmingly inhibits histamine receptors in peripheral tissue. It is proposed that terfenadine slowly associates with the H1-receptor and forms a stable complex from which it dissociates quite slowly.

Animals↗
PubMed1981

A dual mechanism for intestinal motor effects of methyl methacrylate vapor.

The influence of methyl methacrylate (MMA) vapor on the motor activity of the isolated guinea pig ileum is summarized in this report. MMA vapor was delivered to innervated and denervated strips via the tissue bath air supply at a concentration of 755 +/- 38 ppm. Innervated strips usually showed spontaneous motor activities (sma) which developed shortly after the muscle was mounted. None of the denervated strips exhibited sma. Upon exposure to MMA vapor, there was a rapid and significant decrease in sma and in the contractile responses to electric field stimulation and 0.01 mg acetylcholine administration. Denervated strips demonstrated a similar reduction in response magnitude to electric field and drug stimulation but required a longer time period. The persistence of the MMA-induced inhibitory response of the denervated strips indicates that the inhibitory effect is partly due to a direct action of the agent upon the contractile mechanism of the small intestine.

Acetylcholine↗
PubMed1981

Site of alpha blockade in the demonstration of nonvagally mediated gastric acid secretion.

Results of previous reports from this laboratory have indicated that electrical centripetal vagal stimulation in the dog that has a bilateral vagotomy evokes mucus secretion from the pyloric antrum and produces an inhibition of motor activities from the stomach to the terminal ileum. We have subsequently observed that electrical central vagal stimulation after the administration of the alpha adrenolytic, phenoxybenzamine to these preparations results in general augmentation of gastrointestinal motor activity. It was also determined that electrical central vagal stimulation, using the same stimulus parameters that were stimulatory for mucus secretion, now resulted in significant increases in both volume and titratable acid secretions. The intact arterial pressor response during periods of electrical central vagal stimulation which enhanced gastric acid output in the dog that had a bilateral vagotomy eliminates the possibility that the mechanism of acid release involves the necessary suppression of the systemic pressor reflex. It is further concluded that the acid-enhancing effect of phenoxybenzamine appears to be limited to the pyloric antrum, even though the acid is secreted from the corpus. This suggests that the neural portion of the acid effect is confined to the antrum. We have successfully demonstrated that the acid-enhancing reflex effect is associated with a definite rise in the concentration of circulating gastrin.

Animals↗
PubMed1979

Species difference in GI motor response to somatostatin.

Acute experiments were performed on overnight fasted chloralose-urethan anesthetized dogs, cats, rabbits, and rats. Under these conditions, somatostatin practically abolished gastric contractions and decreased GI tonus in all species examined. The canine duodenum, jejunum, and ileum exhibited only a contractile response to somatostatin, whereas motor activities of the small intestines of the cat, rabbit, and rat were inhibited. In all instances and at all dosages, both the inhibitory and excitatory effects showed suggestions of tachyphylaxis. The data also indicate that excitatory or inhibitory effects were not dependent on the presence of long arc pathways. It is concluded that somatostatin exerts a direct stimulatory effect on the canine small intestine that is mediated by the muscularis mucosa.

Animals↗