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Biomedical subjects

J M Sullivan

Publications and source records attributed to J M Sullivan.

At least 127 records · Page 7Linked to original sources
PubMed1983

An autoradiographic study of the distribution of fibers from the dorsal motor nucleus of the vagus to the digestive tube of the rat.

At the present time, complete agreement on the origin and course of parasympathetic preganglionic fibers to the alimentary canal has not been reached. The purpose of this study was to trace vagal fibers to the abdominal cavity and to follow the distribution of these fibers to the digestive tube. The technique used was to label neurons in the dorsal motor nucleus of the vagus (DMX) with 3H-leucine and then to follow the orthograde transport. 16 albino rats were used in this experiment. The right DMX in one group of rats and the left DMX in the other group was injected with 25 microCi of 3H-leucine in three injections. The injection sites and tissue sections from various areas of the digestive tube were processed for autoradiography. A heavy label was observed in the injection site and it could be traced down the vagus nerve through the thorax into the abdomen. Labelled vagal fibers were found in the parasympathetic ganglia of the stomach, small intestine and colon.

Animals↗
PubMed1983

Somatostatin-like immunoreactivity in the retinae of adult and embryonic chickens.

Somatostatin, a tetradecapeptide that inhibits growth hormone release, has a widespread distribution in the central and peripheral nervous systems and other cell types. In the present investigation, the chicken neural retina was studied for the presence of structures exhibiting somatostatin-like immunoreactivity by utilizing an indirect immunofluorescence technique. Controls for specificity of staining were performed on alternate sections. Several types of distinctly labeled neurons and their processes were evident in sections of adult and late embryonic retinae. Cresyl violet staining showed that these neurons, which were scattered peripherally and more numerous centrally, occupied several strata within the inner nuclear, inner plexiform, and ganglion cell layers. Labeled neurites of immunoreactive perikarya coursed within these layers as well, often approaching other immunoreactive cells and fibers. The morphology and position of the somatostatin-containing neurons indicated that these neurons were amacrine, horizontal, or ganglion associational cells. These findings indicate that somatostatin is first detectable in the retina during the late embryonic stages of the chicken.

Animals↗
PubMed1982

Brainstem projections of sensory and motor components of the vagus nerve in the rat.

The sensory and motor connections of the cervical vagus nerves and of its inferior ganglion (nodose ganglion) have been traced in the medulla and upper cervical spinal cord of 16 male Wistar rats by using horseradish peroxidase (HRP) neurohistochemistry. The use of tetramethyl benzidine (TMB) as the substrate for HRP permitted the visualization of transganglionic and retrograde transport in sensory nerve terminals and perikarya, respectively. The vagus nerve in the rat enters the medulla in numerous fascicles with points of entry covering the entire lateral aspect of the medulla extending from level +4 to -6 mm rostrocaudal to the obex. Fascicles of vagal sensory fibers enter the dorsolateral aspect of the medulla and travel to the tractus solitarius (TS) which was labeled for over 8.8 mm in the medulla. The caudal extent of the TS receiving vagal projections was found in lamina V of the cervical spinal cord (C1 to C2). Sensory terminal fields could be visualized bilaterally in the nucleus of the tractus solitarius (nTS), area postrema (ap) and dorsal motor nucleus of the vagus nerve (dmnX). The ipsilateral projection to the nTS and the dmnX was heavier than that found on the contralateral side. The area postrema was intensely labeled on both sides. Motor fibers from HRP-labeled perikarya in the dmnX travel ventromedially in a distinct fascicle and subsequently subdivide into a number of small fiber bundles that traverse the medullary reticular formation in the form of a fine network of HRP-labeled fibers. As these fibers from the dmnX approach the ventrolateral aspect of the medulla they are joined by axons from the nucleus ambiguus (nA), nucleus retroambigualis (nRA) and the retrofacial nucleus (nRF). These latter fibers form hairpin loops in the middle of the reticular formation to accompany the axons from the dmnX exiting from the medulla in a ventrolateral location. HRP-labeled perikarya, in contrast to transganglionically transported HRP in sensory terminals in the nTS, were visualized on one side only, thus indicating that motor control via the vagus nerve is exerted only by motor neurons located ipsilaterally. Sensory information on the other hand, diverges to many nuclear subgroups located on both sides of the medulla.

Accessory Nerve↗
PubMed1982

Long-term captopril therapy: evolving hemodynamic effects.

Nine patients with resistant hypertension received captopril for 12 months. Five received captopril alone, four required additional therapy. In the former, mean blood pressure fell from 109 +/- 4.2 mm Hg to 84 +/- 7.5 mm Hg (P less than 0.025) after seven days. A rise to 101 +/- 19 mm Hg was noted at six and 12 months. Total peripheral resistance fell at seven days but returned to levels above control at six and 12 months. Cardiac index was 3.21 +/- 0.55 liters/min/m2 before treatment, 3.27 +/- 0.56 liters/min/m2 at seven days, and 2.17 +/- 4.0 liters/min/m2 (P less than 0.025) at 12 months. However, forearm blood flow rose from subnormal levels during the 12 months of observation, suggesting a persistent effect on the arterioles of the extremities. Plasma converting enzyme activity was significantly reduced at seven days but was above control levels at six and 12 months. However, plasma renin activity remained elevated, and plasma aldosterone concentration was significantly reduced. The fall in mean blood pressure was not related to the change in plasma converting enzyme activity in patients receiving captopril alone (five patients) or with diuretic (two patients). In the presence of beta-adrenergic blockade and volume depletion (two patients), changes in mean blood pressure appeared to be related to changes in converting enzyme activity. The data suggest that patients with essential hypertension whose blood pressure was not adequately controlled by previous medications may initially respond to captopril with a fall in blood pressure and total peripheral resistance. However, in certain individuals, these effects diminish with time despite addition of diuretics and beta-adrenergic receptor blocking agents.

Adult↗
PubMed1982

Parallel adrenal and renal abnormalities in young patients with essential hypertension.

To determine whether the previously described abnormalities in adrenal secretion and renal blood flow in essential hypertension are associated, we examined the responses to the relevant systems in 18 patients with essential hypertension. Young patients, under 30 years of age, were studied to minimize the likelihood that the phenomena were secondary to long-standing hypertension. To achieve a wide span of sodium balance, studies were performed during a high (200 mEq) sodium intake, a restricted (10 mEg) sodium intake and a restricted sodium intake supplemented by a further short-term diuretic-induced volume deficit (furosemide, 180 to 300 mg, to reduce body weight by 1 to 1.5 kg). The indexes measured included cardiac output (indocyanine green indicator dilution), plasma volume (125 I albumin space), renal blood flow (radioxenon transit), plasma renin activity and aldosterone levels and aldosterone secretory rate. All of these variables, with the exception of blood pressure and total peripheral resistance, were within the normal range during the two diets. However, the aldosterone secretory response to diuretic-induced volume depletion on a low-sodium diet was clearly blunted in nine subjects. These nine subjects (abnormal responders) had a virtually absent aldosterone increment (23 +/- 34 micrograms per 24 hours) compared with the normal responders (502 %/- 70 micrograms per 24 hours). In addition, renal blood flow was significantly higher in these same nine subjects during both a high sodium intake (434 +/- 19 versus 342 +/- 26 ml/100 g per minute) and a restricted sodium intake /446 +/- 11 versus 285 +/- 39 ml/100 g per minute). Yet, there were no significant differences between these two groups in sodium or potassium balance, blood pressure, plasma volume, cardiac index or plasma renin activity during a high or low sodium intake. Normally, control of both aldosterone release by the adrenal and renal perfusion is dominated by angiotensin; an apparently blunted response of both systems suggests that there may be a generalized abnormality in the way angiotensin interacts with its target tissues in many young patients with essential hypertension.

Adrenal Glands↗
PubMed1982

Adrenergic innervation of the left side of the guinea pig heart.

Histological, histochemical fluorescence, and electron microscopic techniques have been utilized to demonstrate the specific distribution of the noradrenergic sympathetic postganglionic fibers to the guinea pig left atrium and ventricle. The majority of these nerves entered the base of the heart. Paravascular bundles of unmyelinated sympathetic postganglionic fibers traversed the left atrioventricular sulcus. From these paravascular plexuses axons accompanied the arteries via periarterial plexuses to the deeper layers of the heart wall. The vascular tree was extremely complex. In the left atrium a relatively abundant noradrenergic innervation was seen within the interstitial connective tissue surrounding the cardiac muscle. In the left ventricle, most of the noradrenergic innervation was located in the tunica adventitia of all the major coronary arterial branches before they entered the cardiac muscle. These larger branches of the coronary arteries were predominantly innervated by the sympathetic postganglionic fibers. Apparently it is from these perivascular nerve plexuses that the left ventricular muscle receives the majority of its noradrenergic innervation.

Adrenergic Fibers↗
PubMed1982

Role of endothelial cell cytoskeleton in control of endothelial permeability.

Increased permeability of the pulmonary microvasculature is felt to cause acute noncardiogenic lung edema, and histological studies of edematous lungs show gaps between apparently healthy endothelial cells. To determine whether alterations in endothelial cell cytoskeletons would alter endothelial permeability, we exposed monolayers of pulmonary artery endothelial cells grown on micropore filters to cytochalasin B or D. Cytochalasin exposed monolayers demonstrated a 2- to 3-fold increase in endothelial permeability that was readily reversible by washing the monolayers free of cytochalasins. Parallel phase contrast and fluorescence microscopy demonstrated retraction of cell cytoplasm and disruption of bundles of microfilaments in cytochalasin exposed cells. These changes also were readily reversed after washing the cells free from cytochalasins. To test the relevance of these findings to an in situ microvasculature, we added cytochalasin B to the perfusate of isolated rabbit lungs and observed that cytochalasin B caused a high permeability lung edema. These studies suggest that endothelial cell cytoskeletons may be important determinants of endothelial permeability.

Animals↗
PubMed1981

Release of prostaglandin I2-like activity from the rat aorta: effect of captopril, furosemide, and sodium.

The effect of captopril, furosemide, indomethacin and intake of sodium on the production of PGI2-like material was studied in the rat aorta. Release of PGI2-like material from these vessels was estimated by its ability to inhibit ADP-induced platelet aggregation. Pretreatment with indomethacin (15 mg/kg/day) reduced the capacity of the aorta to release PGI2-like material. Pretreatment with captopril (10 mg/kg/day) had no effect. Intravenous furosemide (60 microgram/ml plasma volume) increased the capacity of the aorta to inhibit by 28% (p less than 0.25). The inhibitory capacity of aorta removed from rats on a low sodium diet did not differ from those on a high sodium diet. We conclude that the action of furosemide in reducing vascular tone may be related to stimulation of PGI2 synthesis in blood vessels whereas the effect of captopril and sodium in reducing vascular tone may involve a mechanism unrelated to PGI2 synthesis or may involve the synthesis of a prostaglandin other than PGI2.

Adenosine Diphosphate↗
PubMed1981

An orthograde labelling study of axons of the dorsal motor nucleus of the vagus to rat cardiac ganglia as demonstrated by autoradiography.

Central organization of the cardiac vagus has not been clarified. Retrograde changes produced in medulla oblongata neurons after section of vagal branches has favored the dorsal motor nucleus of the vagus (DMNX). Current information concerning the origin, course, and termination of vagal preganglionic fibers within cardiac ganglia is conflicting. The explicit purpose of this study was to determine if vagal fibers originated specifically within the DMNX proper. Fibers within the cardiac ganglia were labelled with 3H-leucine following injection into the DMNX. 12 adult albino rats were studied. DMNX were injected with 25 microCi 3H-leucine reconstituted to microliter. Animals were sacrificed by transcardial perfusion following a 4-day survival period. Serial cross-sections of the caudal pons, medulla oblongata, and thoracic viscera were processed for autoradiography. DMNX possessed a heavy incorporation of the radiochemical. Label was observed within the axons of the vagi. Cardiac ganglia contained labelled vagal fibers in close proximity to the postganglionic somata. Cardiac ganglia containing labelled preganglionic vagal axons were located in the cardiac plexuses and in the epicardium. Results show a labelled vagal preganglionic input to cardiac ganglia from the DMNX.

Animals↗
PubMed1980

Platelet malondialdehyde in cardiovascular disease: effect of prosthetic heart valves and cardioactive drugs on production.

Malondialdehyde (MDA), a product of platelet lipid peroxidation, was measured in human platelet-rich plasma. Levels of 3.19 n moles/10(9) platelets /+- 0.40 S.E. in 11 patients with prosthetic heart valves were elevated (p < 0.25) compared to 17 normal subjects (2.09 /+- 0.13 n moles/10(9) platelets). Reduced production (1.44 /+- 0.28 n moles/10(9) platelets, p < 0.5) was found in 10 patients with unstable angina. Normal levels were found in patients with mitral stenosis, cardiomyopathy or hypertension. Usual serum levels of drugs used in cardiac treatment reduced MDA levels as follows: acetaminophen, 47% (p < .01); aspirin, 58% (p < .05); furosemide, 32.6% (p < .005), and sulfinpyrazone, 41% (p < .05). Digoxin, dipyridamole, heparin, hydrochlorothiazide, lidocaine, nitroglycerin, procainamide, propranolol, quinidine, or warfarin had no significant effect at therapeutic concentrations. None of the drugs explained the enhanced production in patients with prosthetic valves while enhanced production in patients with prosthetic valves while analgesic therapy could explain the decreased levels in other cardiacs. The half-time of platelet survival, measured by suppression of malondialdehyde production, was 3.2 /+- 0.24 days in 9 normal subjects but could not be measured reliably in most patients because of multiple drug therapies. We conclude that the blood platelets of patients with prosthetic heart valves differ from those of normal subjects in their capacity to release malondialdehyde after stimulation with n-ethylmaleimide. Additionally, we find that inhibition of malondialdehyde production by several pharmacologic agents limits the usefulness of this method for the measurement of platelet survival in cardiac patients.

Blood Platelets↗
PubMed1980

Autoradiographic study of the right stellate ganglionic fibers to the cat heart.

Autoradiographic techniques have been employed to demonstrate the distribution of the postganglionic sympathetic cardiac fibers originating from the right stellate ganglion in 3 cats. After exposing the ganglion through a right thoracotomy, a total of 500 muCi of tritiated leucine was injected into the right stellate ganglion of each cat. After 3 days the animals were sacrificed by vascular perfusion. The injected ganglia, the heart and great vessels were processed for autoradiography. The majority of the right stellate ganglionic fibers travelled between the trachea and aortic arch, and entered the cardiac fibers travelled between the trachea and aortic arch, and entered the cardiac plexus. Continuing through the plexus, these fibers coursed between the ascending aorta and the pulmonary arterial trunk to form a periarterial plexus around the left coronary artery and its branches. Most of the fibers followed the distribution of the ventral descending branch of the left coronary artery; a few followed the circumflex artery. A conspicuous subepicardial plexus was derived from the periarterial plexus and was most prominent in the cranial half of the left ventricle. Other fibers arising from the right stellate ganglion descended between the cranial vena cava and the right branch of the pulmonary artery. These ramified on the dorsolateral surface of the right atrium, and also formed a large bundle which passed caudally through the interatrial septum.

Adrenergic Fibers↗
PubMed1980

Methodological issues in the content analysis of brief psychotherapy.

This is a report of a study which extended D. Malan's methodology for examining three factors typically present in the interpretative work of brief psychotherapy. In his work, the higher incidence of two factors (transference-parent link) were found to correlate with a favourable outcome. In this study operational definitions for defence, anxiety and impulse, the conflict factors associated with interpretive work, were developed and tested on Malan's original data. All cases were rated on six factors (Malan's original person-factors plus the additional conflict factors) and their interlinkages. In the 22 cases the rating scheme applied to more than 95 per cent of all interpretations. Malan's findings were replicated. Problems in deriving this complex rating scheme were delineated and directions for future work were outlined.

Aggression↗