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Biomedical subjects

S A Joseph

Publications and source records attributed to S A Joseph.

At least 37 records · Page 2Linked to original sources
PubMed1995

Systemic nitroglycerin induces Fos immunoreactivity in brainstem and forebrain structures of the rat.

Nitroglycerin is a vasodilator which induces vascular relaxation by releasing nitric oxide in the wall of blood vessels. It has been suggested that the cardiovascular inhibitory responses which are induced by this drug are mediated by central structures. In this study, we evaluated the distribution and intensity of Fos immunoreactivity in rat brain nuclei following the systemic administration of nitroglycerin. In the medulla, a significant number of Fos-immunoreactive neurons were observed in the nucleus tractus solitarius, ventrolateral medulla, area postrema and spinal trigeminal nucleus caudalis. A robust staining was seen in the parabrachial nucleus, locus coeruleus and ventrolateral periaqueductal grey. In the hypothalamus, Fos-positive cells were densely packed in the paraventricular and supraoptic nuclei. Other areas where significant staining was observed include the central nucleus of the amygdala and the subfornical organ. These findings demonstrate that the systemic administration of nitroglycerin is capable of activating a spectrum of functionally diverse brain regions. This spectrum includes areas involved in reflex adjustments to nitroglycerin-induced hypotension, areas involved in sensory nociceptive perception and areas associated with integrative regulation of autonomic, behavioral and neuroendocrine functions.

Anesthetics, Inhalation↗
PubMed1994

Nuclear factor-kappa B in rat brain: enhanced DNA-binding activity following convulsant-induced seizures.

The DNA-binding protein nuclear factor-kappa B (NF-kappa B) is a pleiotropic transcription factor which regulates the transcription of specific target genes such as cytokines. The existence of NF-kappa B has not been reported in brain tissue. This is the first report demonstrating the expression of NF-kappa B in the rat brain. After pentylene tetrazole (s.c.)-induced clonic-tonic seizures at an LD50 dose of 85 mg/kg, we have shown a gradual increase in NF-kappa B expression reaching a maximum at 24 h, a decrease at 48 h and again increased at 96 and 120 h. A similar time-dependent pattern was observed for the NF-kappa B subunit p50 expression. The NF-kappa B subunit p65 was not expressed at all. These data suggest a possible underlying mechanism of signal transduction and transcriptional regulation of late-response genes after perturbations in the CNS milieu.

Animals↗
PubMed1994

Efferents of the opiocortin-containing region of the commissural nucleus tractus solitarius.

Efferent projections of the commissural nucleus tractus solitarius (cNTS0 in the region containing opiocortin-immunoreactive (-IR) neurons were identified using Phaseolus vulgaris leucoagglutinin (PHA-L). Efferents were identified in the bed nucleus of the stria terminalis, preoptic area, amygdala, hypothalamus, periaqueductal gray, parabrachial nucleus, locus coeruleus, medullary catecholaminergic groups, and NTS. The PHA-L-IR varicosities in lateral parabrachial nucleus were identified in close association with CRF-IR and enkephalin-IR cells. These data on cNTS projections are consistent with our previous immunocytochemical and lesion studies on opiocortin connectivity and provide anatomical evidence that neurons in the cNTS may influence cardiovascular and sympathetic nervous system function via connectivity with nuclei in the lateral brain stem.

Animals↗
PubMed1994

Monoamine concentrations in cerebrospinal fluid of fetal and newborn sheep.

Monoamine concentrations were measured in cisternal cerebrospinal fluid (CSF) of unanesthetized fetal (115-135 days gestation) and newborn (2-34 days old) sheep. Norepinephrine (NE) and 3,4-dihydroxyphenylacetic acid (DOPAC) concentrations decreased with gestational age; NE CSF concentrations were significantly higher in the newborn (336.4 +/- 61.7 pg/ml; n = 5) compared with the 131- to 135-day-gestation fetuses (104.0 +/- 46.3 pg/ml, n = 3; P < 0.05). Dopamine (DO), homovanillic acid (HVA), and serotonin (5-HT) concentrations in fetal CSF did not change with gestational age, and epinephrine (Epi) was undetectable in most fetal and newborn samples. Hypoxia, induced by giving the ewe 9% O2 in N2 to breathe for 30 min, resulted in a 10.78 +/- 3.94-fold (n = 5) increase of NE concentration in fetal CSF (P < 0.05); DO and DOPAC concentrations did not change. Hypoxia did not increase NE concentrations in CSF of newborn lambs. Inhibition of prostaglandin (PG) synthesis by intravenous infusion of indomethacin significantly reduced plasma prostaglandin E2 concentrations from 7.8 +/- 1.0 (n = 6) to 2.5 +/- 0.2 nmol/l (n = 3; P < 0.05), and was associated with an increase of CSF DOPAC concentrations from 2,156.3 +/- 504.5 (n = 9) to 5,453.6 +/- 1,091.3 pg/ml (n = 5; P < 0.05); NE and DO concentrations did not change significantly. These results show that catecholamines and indoleamines are released in the brain and enter the CSF of fetal sheep from at least 115 days gestation. The data also show that concentrations of some monoamines in CSF are changed by fetal hypoxia or prostaglandin synthesis.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1993

Causal attributions and post-traumatic stress in adolescents.

The aim of the present study was to explore the relationship between causal attributions made by adolescent survivors of the Jupiter cruise ship sinking, and post-traumatic symptomatology in the year following disaster. Evidence is presented that more internal causal attributions for negative and uncontrollable events during the incident are associated with greater post-traumatic stress one year later. The findings are discussed with reference to an attributional model of shame.

Adolescent↗
PubMed1993

Is the left main angulated, stenosed, or "bent" by the guiding catheter?

Exact angiographic and identification of significant stenosis of the left main coronary artery is imperative prior to performing elective percutaneous transluminal coronary angioplasty. A patient is presented with an apparent angiographically significant, but physiologically insignificant, left main stenosis. Both angiographic and physiological methods of detecting "false positive and negative" left main stenoses are discussed.

Aged↗
PubMed1993

A prospective randomized trial of Novoste right versus Judkins catheters for engagement of the right coronary artery during diagnostic catheterization.

There has been little technical advancement in catheter shape for diagnostic cardiac catheterization since the early reports of Sones and colleagues during the development of the procedure. In order to determine the utility of a new catheter that directly, without torque or rotation, engages the right coronary artery (RCA), one hundred patients were randomized between 6Fr standard RCA Judkins (6Fr R4) (Cordis Corporation, Miami, FL, USA) or 6Fr Novoste RCA catheters (Novoste Corporation, Aguadilla, Puerto Rico). Endpoints included the duration of the various aspects of the procedure and a qualitative and quantitative assessment of angiographic quality. The Novoste RCA catheters were associated with statistically decreased times of catheter insertion (42 +/- 37 vs 90 +/- 119 secs), and engagement (31 +/- 35 vs 77 +/- 117 secs), of the right coronary artery as compared to Judkins catheters. Judkins RCA catheters had a significantly higher primary success rate (96%) than the Novoste group (84%, P = 0.045). There was no difference in angiographic quality in either group and no complications occurred during the study. While taller patients (mean 68 in) had increased success with the Novoste catheter, no other clinical, demographic, or anatomical characteristics of the RCA orifice predicted successful engagement and angiography. The direct engagement Novoste RCA catheter is associated with a more expeditious procedure than Judkins catheters when they can engage the RCA orifice. However, Novoste catheters were less successful and required more frequent exchanges to complete the procedure.

Adult↗
PubMed1993

Effects of intracisternal monoamines on breathing movements in fetal sheep.

The effects of intracisternal administration of tyramine on fetal breathing movements (FBM), electrocortical (ECoG) and nuchal muscle activities, and cerebrospinal fluid (CSF) monoamine concentrations have been studied in unanesthetized fetal sheep (124-140 days gestation) in utero. In 18 trials (8 fetuses) infusion of 50 or 100 micrograms/kg tyramine increased the incidence of FBM from 32.2 +/- 2.0 to 79.4 +/- 4.7%/h (P < 0.05) and increased mean breath amplitude from 6.4 +/- 0.4 to 11.8 +/- 1.6 mmHg (P < 0.05). FBM incidence during high-voltage ECoG activity increased from 3.3 +/- 0.6 to 22.5 +/- 3.6%/h (P < 0.05). Tyramine infusion (100 micrograms/kg) significantly increased (P < 0.05) the CSF concentrations of dopamine from 129.5 +/- 26.2 to 10,222.4 +/- 1,103.6 pg/ml, of norepinephrine from 74.7 +/- 11.0 to 2,238.6 +/- 143.5 pg/ml, and of serotonin from 1,824.5 +/- 340.7 to 3,888.7 +/- 1,335.2 pg/ml. Intracisternal injection of dopamine or norepinephrine (10-20 micrograms) caused the rapid onset of large-amplitude FBM, which often continued throughout high-voltage ECoG activity. In contrast, serotonin (20-40 micrograms) caused cessation of FBM and change of the ECoG from low- to high-voltage activity. These results indicate that neuronal release of catecholamines in the CNS has excitatory effects on FBM.

Animals↗
PubMed1992

ACTH1-39 inputs to mesocorticolimbic dopaminergic neurons: light and electron microscopic examination.

Single- and double-labeling immunocytochemical staining procedures were used to examine the relationship between adrenocorticotropin (ACTH)-containing nerve terminals and dopaminergic (DA) neurons in the rat midbrain, using both light and electron microscopy. At the light microscopic level, ACTH neuronal processes were found largely in restricted regions occupied by the mesolimbic and mesocortical DA neurons. At the electron microscopic level, in the central linear nucleus, ACTH axon terminals made symmetric and asymmetric synaptic contacts with DA dendrites, as well as appositions with unlabeled axon terminals which, in turn, synapsed upon DA dendrites. These data suggest that ACTH functions as a neurotransmitter/neuromodulator in the brain, and such ACTH-DA synapses may be important for stress-induced changes in mesocorticolimbic DA neuronal activity.

Adrenocorticotropic Hormone↗
PubMed1992

Efferent projections of the nucleus raphe magnus.

This study was performed to identify supraspinal efferents of the nucleus raphe magnus (NRM) in the rat using the anterograde tracer phaseolus vulgaris leucoagglutinin (PHA-L). NRM-derived PHA-L-ir fibers, with putative terminals, were identified in regions including the lateral hypothalamus, parafascicular nucleus, ventral lateral periaqueductal gray (PAG), locus coeruleus, parabrachial nucleus, A7, A5, and nucleus tractus solitarius. Projections to the PAG demonstrate reciprocity in PAG-NRM connectivity that may modulate the PAG-NRM-spinal cord pathway. The NRM may contribute to supraspinal modulation of nociception by efferents identified in the PAG, as well as locus coeruleus, A7, and A5, which have been shown to project to the spinal cord dorsal horn. Our results provide neuroanatomical support for NRM involvement in supraspinal mechanism(s) for modulation of nociception.

Animals↗
PubMed1990

Catecholamine neurons in fetal brain: effects on breathing movements and electrocorticogram.

We investigated the effect of increasing the synaptic concentration of catecholamines released from central pathways on breathing movements and electrocortical (ECoG) activity in fetal sheep in utero. In 11 trials (9 fetuses) intravenous infusion of the noradrenergic uptake inhibitor desipramine (DMI) resulted in an initial increase in the incidence of breathing movements from 47.8 +/- 2.2%/h to a maximum of 77.9 +/- 5.5%/h (P less than 0.05) followed by a subsequent decrease to 18.8 +/- 2.7%/h (P less than 0.05), which was associated with a decrease in the incidence of low-voltage ECoG activity. Mean breath amplitude also increased after DMI infusion from 5.8 +/- 0.2 mmHg to a peak of 8.9 +/- 0.9 mmHg (P less than 0.05). In five fetuses, intravenous injection of the alpha 1-receptor antagonist prazosin 30 min after the start of the DMI infusion blocked the increase of breath amplitude observed when DMI was given alone. Intracisternal infusion of 6-hydroxydopamine (6-OHDA, which causes an initial displacement of transmitter stores followed by a neurotoxic action) in six fetuses caused an increase in mean breath amplitude from 6.6 +/- 0.3 mmHg (control) to 22.3 +/- 5.5 mmHg (P less than 0.05) and a prolonged episode of breathing movements (168.5 +/- 47.2 min). The incidence of low-voltage ECoG activity was also increased significantly. A second infusion of 6-OHDA, 2 days after the first, had no effect on breathing movements or ECoG activities. The two treatments with 6-OHDA also resulted in a significant reduction in the response to intravenous infusion of DMI, indicating that endogenous release of norepinephrine had been reduced by the neurotoxin. These results suggest that 1) there is normally some tonic release of norepinephrine from central pathways, but this release is insufficient to stimulate sustained fetal breathing, and 2) accumulation in the synaptic cleft of catecholamines from central neurons is able to stimulate fetal breathing and promote low-voltage ECoG activity. Possible mechanisms that normally limit the activity of central catecholamine pathways before birth are discussed.

Animals↗
PubMed1988

Immunocytochemical localization of pro-opiomelanocortin neurons in human brain areas subserving stimulation analgesia.

The distribution of pro-opiomelanocortin (beta-endorphin, adrenocorticotropic hormone, and 16-K) neurons and fiber projections was evaluated immunocytochemically in 50-mu thick cryostat sections of human diencephalon and midbrain. Specific attention was focused upon regions in which deep brain stimulation has been most effective in the relief of selected chronic pain syndromes. This study revealed a remarkable, nearly point-to-point correlation between clinically effective stimulation sites and the distribution of pro-opiomelanocortin fibers in the human brain. Of particular interest was the dense innervation of the periventricular stratum along the third ventricle, the parafascicular centromedian region of the thalamus, and the periaqueductal gray matter of the midbrain. This study provides anatomical support for the hypothesis that beta-endorphin-containing neuronal systems may contribute to stimulation analgesia in the human.

Adolescent↗
PubMed1987

The effects of nitrous oxide on the central endogenous pro-opiomelanocortin system in the rat.

The hypothesis that nitrous oxide stimulates the central pro-opiomelanocortin system in vivo was explored in this study. A concentration-dependent stimulation of central pro-opiomelanocortin neuropeptides was demonstrated after exposures to variable concentrations of nitrous oxide with oxygen. Rats exposed to 60% and 80% nitrous oxide with oxygen demonstrated an elevation of beta-endorphin concentration along the neuraxis involved with analgesia; no similar effect was observed in alpha-MSH concentration, neither duration of exposure nor acclimation to the enclosed environment altered this stimulation. The discontinuation of nitrous oxide exposure resulted in the diminution of beta-endorphin concentration to pre-exposure levels in 15-30 min. With an ACTH1-39 antisera, a semiquantitative increase in opiocortin immunoreactivity after exposures to nitrous oxide was demonstrated. In conclusion, the increase in beta-endorphin concentration and immunoreactive ACTH1-39 staining in the cells of origin, areas of fiber projection and terminal fields suggest that nitrous oxide stimulates the central pro-opiomelanocortin system in vivo in the rat.

Administration, Inhalation↗