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Biomedical subjects

J Lincoln

Publications and source records attributed to J Lincoln.

68 records · Page 4Linked to original sources
PubMed1986

Adrenergic and cholinergic innervation of the smooth and striated muscle components of the urethra from patients with spinal cord injury.

The adrenergic and cholinergic innervation of the smooth and striated muscle components of the urethra from spinal cord injury patients with detrusor sphincter dyssynergia were investigated neurochemically and histochemically. Catecholamine fluorescence histochemistry provided no evidence for the presence of adrenergic nerves associated with the skeletal muscle. The noradrenaline content of this region probably reflects the endogenous levels in adrenergic nerves associated with the blood vessels supplying the skeletal muscle. Choline acetyltransferase activity in the skeletal muscle was significantly lower in patients with cervical lesions than in those with thoracic lesions (p less than 0.01). The noradrenaline content of the smooth muscle was significantly lower in cervical lesions than in thoracic lesions in both the mid (p less than 0.02) and the distal (p less than 0.001) regions of the urethra. The proximal region revealed similar noradrenaline levels in both groups of spinal cord injury patients. The results are discussed in relation to the role of the autonomic nervous system in the control of voiding and to the presence of increased sympathetic outflow in patients with spinal cord lesions at higher levels.

Adolescent↗
PubMed1985

Enteric nerves in diabetic rats: increase in vasoactive intestinal polypeptide but not substance P.

The distribution of vasoactive intestinal polypeptide (VIP) and substance P-like immunoreactivities was studied by immunohistochemistry in the myenteric plexus and circular muscle layer of the ileum and proximal colon of rats 8 wk after induction of diabetes with streptozotocin. A consistent increase was observed in fluorescence intensity of VIP-like immunoreactivity in the nerve fibers, and intensely stained cell bodies were significantly more frequent in the myenteric plexus of the ileum (p less than 0.001) from diabetic animals. Some varicosities of VIP-like immunoreactive fibers in the myenteric plexus appeared to be enlarged. Vasoactive intestinal polypeptide-like immunoreactivity was increased and VIP-like immunoreactive nerves appeared thicker in the circular muscle layer of both diabetic ileum and proximal colon. The VIP levels were measured biochemically in tissue consisting of the smooth muscle layers and myenteric plexus. A significant increase in the VIP content per centimeter of intestine was found in both the ileum (p less than and proximal colon (p less than 0.01) from diabetic rats. In contrast, no apparent change in substance P innervation was observed immunohistochemically in the myenteric plexus and circular muscle layer of either diabetic ileum or proximal colon when compared with controls. The results are discussed in relation to the symptoms of autonomic neuropathy of the gut in diabetes.

Animals↗
PubMed1984

Rat bladder in the early stages of streptozotocin-induced diabetes: adrenergic and cholinergic innervation.

The adrenergic and cholinergic innervation of the bladder was studied in streptozotocin-diabetic rats. The presence of hypertrophy and distension in the 'diabetic' bladders necessitates care in assessing changes occurring in the nerves, factors which are also relevant to clinical histochemical studies. Biochemical assays of cholinergic enzymes revealed decreased activities per g wet weight tissue. However, the total activities of choline acetyltransferase and acetylcholinesterase per whole bladder were significantly increased after 2 weeks of diabetes with greater changes by 8 weeks. Total dopamine levels per bladder were significantly higher than in control rats in the 2-week but not the 8-week group of animals; this may indicate an initial increase in adrenergic nerve activity. There was no impairment in the ability of the detrusor muscle to respond to noradrenaline, acetylcholine or to cholinergic nerve stimulation. Shortly after induction of diabetes streptozotocin-treated rats display polyuria. It is proposed that the activity of the bladder is therefore stimulated to allow greater volumes of urine to be passed. The results are discussed in relation to human diabetes mellitus where clinical studies have implicated a neuropathic origin to bladder dysfunction.

Acetylcholine↗
PubMed1984

The smooth muscle of rat bladder in the early stages of streptozotocin-induced diabetes.

The morphology of the rat bladder was studied following 8 weeks of streptozotocin-induced diabetes, at which stage distension of the bladder had occurred. Evidence is presented for hypertrophy of the smooth muscle of the bladder wall in experimental diabetes. It is suggested that the morphological changes found in the diabetic rat bladder are associated with polyuria. The results are discussed in relation to clinical studies of bladder dysfunction in diabetes mellitus.

Animals↗
PubMed1984

Myenteric plexus in streptozotocin-treated rats. Neurochemical and histochemical evidence for diabetic neuropathy in the gut.

Adrenergic, cholinergic, and serotoninergic nerves were studied in the myenteric plexus of ileum and colon from streptozotocin-treated rats, an animal model of juvenile-onset diabetes. In view of clinical reports implicating diabetic autonomic neuropathy as the cause of gastrointestinal dysfunction in diabetes mellitus, neurochemical and histochemical techniques were used to study changes in the innervation of the gut. In the myenteric plexus of the ileum from diabetic animals, adrenergic nerves displayed signs of degeneration and the brightness of fluorescence in serotoninlike immunoreactive nerves was lower. Cholinergic nerves, however, did not display any signs of reduction in the ileum, and both choline acetyltransferase and acetylcholinesterase activities per centimeter were increased. In contrast, in the proximal colon 8 wk after induction of diabetes, neurochemical assays revealed significant increases in noradrenaline and serotonin levels as well as choline acetyltransferase activity, although no obvious changes in the pattern of innervation could be detected histochemically. The results indicate that changes do occur in the innervation of the gut of the streptozotocin-diabetic model shortly after the induction of diabetes, although they differ significantly in the ileum and colon; these may be of relevance to the types of gastrointestinal dysfunction displayed in human diabetes.

Animals↗
PubMed1983

Vasoactive intestinal polypeptide-like immunoreactive nerves in diabetic penis. A comparison between streptozotocin-treated rats and man.

Vasoactive intestinal polypeptide (VIP) has been demonstrated by immunofluorescence histochemistry in nerves in human and rat penile tissue. A reduction in VIP-like immunoreactivity in nerves was revealed in tissue from streptozotocin-diabetic rats and a human diabetic with impotence. These results suggest that an impairment in the VIP-ergic innervation in penile tissue may be an important factor in the development of impotence in diabetes. They also support the view that the streptozotocin-treated rat is a useful experimental model for diabetic autonomic neuropathy.

Animals↗
PubMed1982

Regional differences in the density of perivascular nerves and varicosities, noradrenaline content and responses to nerve stimulation in the rabbit ear artery.

Quantitative image analysis of fluorescent nerve following histochemical localization of monoamines in stretch preparations of the rabbit ear artery (REA) reveals marked differences in the density of innervation between the proximal and distal regions. The innervation in the proximal region is about twice as dense as that in the distal region and there are approximately 10,500 and 6,500 varicosities per mm2 vessel area in these two regions, respectively. These varicosities have approximately the same mean diameter throughout the length of the vessel. The noradrenaline contents per gram wet weight of tissue in the proximal and distal regions are 1.93 and 0.94 microgram, respectively. It is estimated that noradrenaline contents per mm2 nerve plexus area are 0.30 and 0.08 ng and that the nerve endings consist 2.8 x 10(-14) and 1.2 x 10(-14) g per varicosity in the proximal and distal REA, respectively. Sympathetic nerve stimulation in vitro with frequencies up to 8 Hz elicits larger and faster contractions in the proximal REA and the threshold frequency is less than in the distal region. This study also indicates that care should be taken to use the same region when using the REA for pharmacological and physiological studies.

Adrenergic Fibers↗
PubMed1981

Alterations in protein synthetic capability of nerve cells in Alzheimer's disease.

Cytoplasmic RNA content, nuclear and nucleolar volume are all significantly reduced in nerve cells of the temporal cortex in cases of Alzheimer's disease, examined both at diagnostic craniotomy and post mortem, when compared with non=demented control cases of similar age. On average, at necropsy, all three parameters are equally reduced by about 40-50%, but in biopsy cases, nuclear volume is decreased by the greatest amount (43%), followed by nucleolar volume is decreased by the greatest amount (43%), followed by nucleolar volume (36%), and cytoplasmic RNA (26%). These findings indicate that a change in protein synthesis occurs daily in the course of Alzheimer's disease which may result from a primary alteration within the nuclear apparatus.

Adult↗
PubMed1980

Changes in the monoamine containing neurones of the human CNS in senile dementia.

In thirteen cases of senile dementia of the Alzheimer type severe loss of nerve cells from the locus caeruleus was frequently seen together with reductions in nucleolar volume and cytoplasmic RNA in surviving cells, averaging 14 and 21 per cent respectively. These histological findings were matched in two cases by biochemical measurements of loss of noradrenaline from all brain regions examined, ranging from 10 per cent in temporal cortex to 53 per cent in hypothalamus. By contrast, neither nucleolar volume nor cytoplasmic RNA was altered in cells of the substantia nigra, nor was dopamine content significantly altered in most regions. In vascular dementia neither noradrenaline nor dopamine metabolism was changed except in regions of local circulatory deficiency. These findings provide evidence of a primary degeneration of the noradrenergic system in Alzheimer type dementia.

Aged↗
PubMedDate not supplied

Nuclear inclusions in Alzheimer's disease.

Biopsy samples of parietal cortex from seven patients undergoing atrio-ventricular shunt operations have been examined electron microscopically. Five were suffering from Alzheimer's disease, while two were subjects with normotensive hydrocephalus following previous head injuries. Intranuclear neuronal, inclusions of three types were found. Most frequent was the intranuclear rodlet, which was commonly observed in four of the patients with Alzheimer's disease, but in one block only from one of the hydrocephalus cases. The other two types, namely the spherical inclusion body and the vermicellar-like inclusion, were found less commonly and in only two cases. No inclusions were seen in glial nuclei.

Aged↗
PubMedDate not supplied

Neurofibrillary pathology and protein synthetic capability in nerve cells in Alzheimer's disease.

Nucleolar volume was measured in nerve cells of the temporal cortex in cases of Alzheimer's disease, obtained at both biopsy and autopsy. Measurements were made on those nerve cells containing neurofibrillary tangles and also on ones free of such changes. Results showed that nucleolar volume is significantly reduced, by at least 40%, in both tangle and non-tangle bearing cells, in both biopsy and autopsy cases, when compared with corresponding values from appropriate control cases. Furthermore, in the autopsy cases, nerve cell nucleolar volume was reduced by a further 30% in tangle bearing cells compared to non-tangle bearing neighbours. No such difference was noted in these cells in the biopsy cases. These findings imply that alterations in protein synthetic capability occur in nerve cells early in the course of Alzheimer's disease, and that this change is not, at least in these initial stages, related to accumulation of neurofibrillary material within the cell body, although later on such accumulation may result in added disruption of cell metabolism.

Adult↗