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Biomedical subjects

J Wharton

Publications and source records attributed to J Wharton.

At least 91 records · Page 5Linked to original sources
PubMed1990

Myocardial localization and isoforms of neural cell adhesion molecule (N-CAM) in the developing and transplanted human heart.

Neural cell adhesion molecule (N-CAM) has been implicated in cellular interactions involved in cardiac morphogenesis and innervation. Immunohistochemical techniques and Western blot analysis were used to determine the localization and isoforms of N-CAM in the developing and extrinsically denervated human heart. Myocardial and conducting cells in the fetal heart (7-24 wk gestation) exhibited sarcolemmal immunoreactivity, the major desialo N-CAM isoforms being 150, 145, 120, 115, and 110 kD. N-CAM expression appeared to be downregulated in the myocardium during adult life, with relatively little sarcolemmal immunoreactivity being detected in normal donor tissues. In contrast to the temporal changes observed in the myocardium, both the developing and mature cardiac innervation displayed N-CAM immunofluorescence staining, localized to neuronal cell bodies, nerve fascicles and fibres. Extrinsically denervated cardiac allografts, obtained 2 d to 91 mo after transplantation, showed extensive sarcolemmal and intercalated disc immunostaining and expression of 125-, 120-, and 115-kD isoforms. Tissues from explanted recipient hearts and atrial appendage samples obtained during coronary bypass graft operations were also examined and displayed varying amounts of N-CAM immunoreactivity. We conclude that the expression of N-CAM immunoreactivity and isoforms in the human heart is developmentally regulated and may be modulated by factors such as cardiac innervation and myocardial hypertrophy.

Adult↗
PubMed1990

Immunohistochemical localization of peptide-containing nerves in human airways: age-related changes.

Bronchial reactivity changes during childhood, indicating possible changes in neural control. Nerves supplying the intrapulmonary airways were therefore studied in autopsy tissue from 14 normal infants (0 to 3.5 yr), 3 children (8.3 to 10.75 yr), and 4 adults (17 to 24 yr). An indirect immunofluorescence technique was used to study the distribution and relative number of nerve fibers containing the general neuronal markers protein gene product 9.5 and synaptophysin. Nerve subpopulations were identified using antisera to neuropeptide tyrosine, vasoactive intestine polypeptide, somatostatin, substance P, calcitonin gene-related peptide, and the enzyme tyrosine hydroxylase. Between birth and 3 yr, the distribution and relative number of immunoreactive nerves shown by both the general neuronal markers and specific antisera did not change. Neuropeptide tyrosine-immunoreactive nerves were the most common peptide-containing nerve subpopulation identified in the human lung, supplying bronchial smooth muscle, submucosal glands, cartilage, and submucosa. Other peptide-containing nerves exhibited distinct distribution patterns. Two differences in the airway innervation were identified between cases aged 0 to 3.5 yr and the older age groups. Relatively fewer peptide-containing nerves occurred in the adult bronchioli and respiratory unit, but the relative number of vasoactive intestinal polypeptide-containing nerves supplying the bronchial and bronchiolar smooth muscle was greater in the two older age groups. Given these apparent age-related differences in the number of peptide-containing nerves supplying the human airway, studies on the development of peptide receptors are indicated.

Adolescent↗
PubMed1989

Neural cell adhesion molecule (N-CAM) expression during cardiac development in the rat.

Neural cell adhesion molecule (N-CAM) expression was examined in the rat heart using immunohistochemical and immunochemical techniques. N-CAM immunoreactivity was displayed by myocardial cells from embryonic day E12 and by cardiac nerves when first identified at day E18. Myocardial immunostaining increased up until about postnatal day 1 and then declined rapidly thereafter whereas neural immunoreactivity persisted in the adult. N-CAM cardiac isoforms also exhibited developmental changes from the main embryonic moieties (105 and 145 kDa) to the principal postnatal (125 and 155 kDa) and adult isoforms (125 kDa). Cardiac N-CAM expression is therefore subject to temporal regulation and may modulate cellular interactions in the developing heart.

Animals↗
PubMed1989

Neural cell adhesion molecule is expressed by smooth muscle cells during the development of the rat vascular system.

The presence and distribution of neural cell adhesion molecule (N-CAM) was examined by light and electron microscopical immunocytochemistry in the descending thoracic aorta, the superior mesenteric artery and mesenteric arteries from fetal and adult rats (embryonic day 15 to post-natal day 90). In embryonic and early post-natal rats, N-CAM immunoreactivity was localized in perivascular nerves, in the smooth muscle cell plasma membrane and basal lamina. In nerves, N-CAM-immunoreactive sites were found associated with both the axon and Schwann cell membranes. N-CAM immunoreactivity was also found associated with the surface of adventitial fibroblast-like cells and with collagen fibrils, in regions where these fibrils were in contact with smooth muscle cells. In mature vessels N-CAM immunoreactivity was found to be restricted to the perivascular innervation and the surface of fibroblast-like cells. These observations indicate that N-CAM is expressed transiently in rat vascular tissues during development and is localized not only on the surface of smooth muscle cells but also in association with extracellular matrix components.

Aging↗
PubMed1989

Comparison of peptidergic mechanisms in different parts of the guinea pig superior mesenteric artery: immunocytochemistry at the light and ultrastructural levels and responses in vitro of large and small arteries.

The presence and distribution of peptide-containing nerve fibres and axon terminals have been studied in the proximal part of the superior mesenteric artery (SMA) (i.e. conductance vessel) and in the finer ramifications of the SMA close to the intestine (outer diameter 200 microns, i.e. resistance vessel). Light microscopic immunocytochemistry revealed that the proximal part of the SMA possessed a rich supply of neuropeptide Y (NPY)- and tyrosine hydroxylase (TH)-immunoreactive nerve fibres, forming a loose perivascular network which increased in density distally. The vasoactive intestinal peptide (VIP) immunoreactivity was moderate in the proximal artery and only a few VIP fibres could be identified in the distal portion of the SMA. Calcitonin gene-related peptide (CGRP)-, neurokinin (NK)- and substance P (SP)-immunoreactive fibres had an intermediate density in both arterial regions, but their distribution pattern varied. Electron microscopic immunocytochemistry showed that NPY-immunoreactive nerve terminals were close to the smooth muscle cells of the medial layer in both parts of the SMA, indicative of a vasomotor role. Although the VIP-immunoreactive terminals had a similar localization they were seen less frequently. CGRP-, NK- and SP-immunoreactive axons had an identical distribution in the two vascular regions. Interestingly, they were usually seen more distant from the medial layer, localized in the adventitia. Examination of vasomotor responses to perivascular peptides revealed significant regional differences: NPY produced only weak contractions (13 +/- 3%) of proximal vessel segment of the conductance type, while strong concentration-dependent contractions were seen in distal parts of the SMA (resistance vessel). In neither region was any interaction with noradrenaline demonstrated. Proximal segments of the SMA revealed a stronger and more potent response to VIP and peptide histidine isoleucine than did distal segments, while on the other hand acetylcholine was more potent and elicited stronger effects in distal segments. CGRP, NKA and SP relaxed precontracted arteries by 50-75% and there was no significant difference in responsiveness to these peptides in the two regions of the SMA.

Animals↗
PubMed1989

Autoradiographic localization of endothelin-1 binding sites in the cardiovascular and respiratory systems.

Specific high-affinity binding sites for endothelin-1 (ET-1) have been demonstrated in peripheral tissues using the technique of in vitro receptor autoradiography. Binding was time dependent and saturable and inhibited by coincubation with an excess of unlabeled ET-1 but resistant to dissociation. Binding sites were localized to blood vessels of all sizes including coronary arteries, intrapulmonary vessels, and intrarenal and intrasplenic arteries. In addition, high-affinity binding sites were identified on airway smooth muscle, over alveolar septa, and on nerve trunks. Scatchard analysis of the data revealed a Bmax of 250 amol/mm2 and a Kd of 0.1 nM for the binding of rat tracheal smooth muscle, with similar values for porcine coronary artery. The localization of binding sites is consistent with the known effects of ET-1 and suggests a direct action on specific receptors.

Animals↗
PubMed1989

A study of nerves containing peptides in the pulmonary vasculature of healthy infants and children and of those with pulmonary hypertension.

Nerves containing peptides that supply the human intrapulmonary vasculature were studied in 21 controls aged one month to 24 years and in 13 patients with pulmonary hypertension aged 11 days to eight years. An indirect immunofluorescence technique was used to study the distribution and relative density of nerve fibres containing the general neuronal marker, protein gene product 9.5; tyrosine hydroxylase; synaptophysin; neuropeptide tyrosine; vasoactive intestinal polypeptide; substance P, somatostatin; and calcitonin gene related peptide. At all ages in normal and hypertensive lungs neuropeptide tyrosine was the predominant neuropeptide associated with the pulmonary vascular nerves. In normal lungs the relative density of nerve fibres increased during childhood only in the arteries of the respiratory unit. Pulmonary hypertension was associated with the premature innervation of these arteries during the first year of life. Innervation of small, abnormally thick-walled pre-capillary vessels by predominantly vasoconstrictor nerves may help to explain the susceptibility of infants to pulmonary hypertensive crises.

Age Factors↗
PubMed1989

Peptide-containing nerves in the rat femoral artery and vein. An immunocytochemical and vasomotor study.

Peptide-containing nerves have been examined in the rat femoral artery and vein using immunocytochemical and vasomotor techniques. The general neuronal marker PGP 9.5 revealed a moderate supply of nerve fibres and fascicles forming a loose network in the adventitia and the adventitial-medial border of the artery and vein. The majority of the nerve fibres in both the artery and vein displayed immunoreactivity for neuropeptide Y (NPY) and tyrosine hydroxylase (TH). The distribution pattern and number of these two types correlated well. The artery had a slightly richer PGP 9.5- immunoreactive nerve supply compared to the vein, but the nerve plexus in the vein displayed a more uniform arrangement. In contrast, relatively few nerve fibres displayed calcitonin gene-related peptide, substance P, or vasoactive intestinal peptide immunoreactivity in either the artery or vein. The calcitonin gene-related peptide immunoreactive fibres had a similar distribution to that of the substance P containing fibres. Using a sensitive in vitro method the vasomotor responses to perivascular peptides were characterized. In the femoral artery NPY potentiated alpha 1-adrenoceptor mediated contractions, and had very little effect by itself. In contrast, 10(-7) M NPY contracted femoral veins by up to 68% relative to 60 mM potassium induced contraction, and there was no potentiation of alpha-adrenoceptor mediated contractions. Acetylcholine, peptide histidine isoleucine, vasoactive intestinal peptide, substance P and calcitonin gene-related peptide, all relaxed the contracted femoral artery and vein. Regarding the putative parasympathetic neurotransmitters, acetylcholine caused stronger relaxation of veins as compared to arteries whereas for vasoactive intestinal peptide and peptide histidine isoleucine the relaxations were stronger in the arterial preparation. These three agonists were more potent in the femoral vein. Substance P was more potent on the femoral vein, having the same maximum response in both preparations. On the other hand, the response induced by CGRP was some three times greater in the venous than in the arterial preparation. These data reveal that although there appear to be only minor differences in the peptidergic innervation of the rat femoral artery and vein pronounced differences occur in the peptide effector responses. The data support the concept that perivascular peptides play different roles in regulating various parts of the circulation.

Acetylcholine↗
PubMed1988

The presence and molecular forms of cardiodilatin immunoreactivity in the human and rat right atrium.

A sensitive and specific radioimmunoassay has been developed for cardiodilatin, the N-terminal peptide sequence of the atrial natriuretic peptide (ANP) prohormone. Cardiodilatin-immunoreactivity (-IR) concentrations in the human right atrial appendage were found to correlate with ANP-IR concentrations, determined by an established radioimmunoassay, (cardiodilatin-IR = 13.2 +/- 1.2 nmol/g, ANP-IR = 19.8 +/- 2.0 nmol/g, r = 0.80, p less than 0.001). Characterisation of the cardiodilatin-IR in the human and rat right atrium by gel permeation and fast protein liquid chromatography revealed only two cardiodilatin-IR molecular forms. The larger more hydrophobic form, the majority of the cardiodilatin-IR, contained in addition ANP-IR and therefore represents the prohormone. The smaller, less hydrophobic form, lacked ANP-IR and thus represents the cleaved N-terminal peptide sequence of the prohormone. These findings indicate that the prohormone is the major molecular form in the human and rat atrium. Furthermore, they demonstrate that a single large N-terminal peptide, cardiodilatin, derived from the prohormone, may exist as a distinct molecular form in the atrium of these species.

Animals↗
PubMed1988

Postnatal development of the innervation and paraganglia in the porcine pulmonary arterial bed.

The innervation of the pulmonary trunk and pulmonary arterial bed was studied in 17 pigs from birth to 6 months of age. After birth, the pulmonary trunk and extra- and intra-pulmonary arteries contained neurofilament and protein gene-product-immunoreactive nerve fibres in both the adventitia and media. The density of nerve fibres increased from birth to 2 months, this being most marked during the first 2 weeks of life. Most of the fibres in the media were presumed to be sympathetic in origin as they contained both neuropeptide tyrosine and tyrosine hydroxylase immunoreactivity. Fibres were associated with the vasa-vasorum and vascular smooth muscle running around the vessel, between the elastic laminae and smooth muscle cells, in the outer two-thirds of the media. Vasoactive intestinal polypeptide and calcitonin gene-related peptide-immunoreactive nerve fibres were found to be associated with the pulmonary trunk and extra-pulmonary artery, but generally not with the intra-pulmonary arteries. Tyrosine hydroxylase immunoreactivity was detected in the glomus cells at birth, but peptide immunoreactivity (enkephalin) was not demonstrated in paraganglia until 14 days of age. Adaptation to extra-uterine life is associated with rapid development changes in the innervation of the pig pulmonary trunk, extra- and intra-pulmonary arteries and in the expression of peptide immunoreactivity in both nerve fibres and glomus cells. These changes may have a role in the postnatal adaptation of the pulmonary circulation.

Aging↗
PubMed1988

Ventricular and atrial myocytes of newborn rats synthesise and secrete atrial natriuretic peptide in culture: light- and electron-microscopical localisation and chromatographic examination of stored and secreted molecular forms.

We have demonstrated that atrial natriuretic peptide-like immunoreactivity is stored and secreted by ventricular and atrial myocytes in dissociated cell culture preparations from the heart of newborn rat. Culture preparations were maintained in either foetal calf serum-supplemented medium 199 or in hormone-supplemented, serum-free medium 199. The presence of atrial natriuretic peptide-like immunoreactivity in the cultured myocytes was demonstrated at both light- and electron-microscopical levels. Release of atrial natriuretic peptide-like immunoreactivity into the culture medium was measured by radioimmunoassay; molecular forms of the stored and secreted peptide were determined by gel column chromatography. The atrial natriuretic peptide-like immunoreactivity of cultured atrial and ventricular myocytes was concentrated in the perinuclear cytoplasm and was localised to electron-dense secretory granules. The number of immunoreactive ventricular myocytes and the intensity of their immunofluorescence changed with time in culture and was higher in cultures in foetal calf serum-supplemented medium than in serum-free medium. Gamma-atrial natriuretic peptide was stored and released by cultured atrial and ventricular myocytes, but was broken down to alpha-atrial natriuretic peptide in the growth medium. This process was foetal calf serum-independent, since it occurred in both the media used, indicating that cardiac myocytes in culture may release a factor that cleaves gamma-atrial natriuretic peptide to form alpha-atrial natriuretic peptide.

Animals↗
PubMed1988

Immunohistochemical and ultrastructural localisation of peptide-containing nerves and myocardial cells in the human atrial appendage.

The innervation and myocardial cells of the human atrial appendage were investigated by means of immunocytochemical and ultrastructural techniques using both tissue sections and whole mount preparations. A dense innervation of the myocardium, blood vessels and endocardium was revealed with antisera to general neuronal (protein gene product 9.5 and synaptophysin) and Schwann cell markers (S-100). The majority of nerve fibres possessed neuropeptide Y immunoreactivity and were found associated with myocardial cells, around small arteries and arterioles at the adventitial-medial border and forming a plexus in the endocardium. Subpopulations of nerve fibres displayed immunoreactivity for vasoactive intestinal polypeptide, somatostatin, substance P and calcitonin gene-related peptide. In whole-mount preparations of endocardium, substance P and calcitonin gene-related peptide immunoreactivities were found to coexist in the same varicose nerve terminals. Ultrastructural studies revealed the presence of numerous varicose terminals associated with myocardial, vascular smooth muscle and endothelial cells. Neuropeptide Y immunoreactivity was localised to large electron-dense secretory vesicles in nerve terminals which also contained numerous small vesicles. Atrial natriuretic peptide immunoreactivity occurred exclusively in myocardial cells where it was localised to large secretory vesicles. The human atrial appendage comprises a neuroendocrine complex of peptide-containing nerves and myocardial cells producing ANP.

Adult↗
PubMed1988

Protein gene product 9.5 (PGP 9.5). A new neuronal marker visualizing the whole uterine innervation and pregnancy-induced and developmental changes in the guinea pig.

The guinea pig uterus is supplied by different populations of nerves which can be demonstrated by specific immunocytochemical and histochemical techniques. So far, there has been no single marker displaying entire peripheral innervation patterns. Recently, protein gene product (PGP) 9.5, a cytoplasmic protein in neurons and neuroendocrine cells, was found to visualize both different populations and subtypes of nerves. This prompted the present study of using PGP 9.5 for visualization of the whole uterine innervation. This was performed by the indirect immunofluorescence method using antiserum to PGP 9.5 raised in rabbits. PGP-immunoreactivity was present in all neuronal parts of the extrinsic and intrinsic uterine innervation, including different subpopulations of nerves. This was verified by chemical sympathectomy and sensory denervation with 6-hydroxydopamine and capsaicin-treatment respectively, and double immunostaining. By term a disappearance of uterine PGP-nerve-immunoreactivity was observed which was almost complete in fetus-bearing uterine tissue and further strengthens previous assumptions of a general, pregnancy-induced uterine neuronal degeneration. The developmental time-course and morphology of PGP-immunoreactive nerve structures was similar to that for other neuronal markers and support the suggestion of PGP-immunoreactivity as a general marker for the entire uterine innervation, and suggests that the presence of PGP 9.5-immunoreactivity may coincide with functional maturation of uterine innervation.

Animals↗
PubMed1988

Ontogenetic development of the guinea pig uterine innervation. An immunohistochemical study of different neuronal markers, neuropeptides and S-100 protein.

The ontogenetic development of the guinea pig uterine autonomic innervation was studied immunohistochemically using neurofibrillary protein (NF) and neuron specific enolase (NSE) as general neuronal markers, tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH) as specific markers for adrenergic innervation and S-100 protein as marker for Schwann cell structure and/or function. In addition, comparisons were made of the development of the different populations of peptide-containing nerves. The structure and time of appearance were similar for nerves with NF-, NSE-, TH- and DBH-immunoreactivities, which were first present in the organ periphery as coarse nerve trunks, then extending centrally and branching into non-varicose nerves. From these, varicose nerves developed first in relation to vessels and then in association with the myometrial smooth musculature. Development was completed earlier in the cervix than in the uterine horns suggesting differences in local environment. In comparison, S-100 nerve-immunoreactivity appeared later but attained complete development more rapidly than axonal structures. Neuropeptide Y-immunoreactive nerves showed a similar developmental pattern to presumed adrenergic nerves, further verifying the assumption of intraneuronal localization of NPY in uterine adrenergic nerves. Other peptide-containing nerves were developed later probably reflecting differences in neuronal growth properties.

Animals↗
PubMed1988

Effects of pregnancy on the extrinsic innervation of the guinea pig uterus. A histochemical, immunohistochemical and ultrastructural study.

The extrinsic innervation of the guinea pig uterus was studied by immunohistochemical, ultrastructural and enzyme histochemical methods. The extrinsic innervation was organized in two major ways. One consisted of nerve trunks and non-varicose nerve fibres running in the suspensory ligament, and the other of a plexus of varicose nerve fibres surrounding vessels, and non-vessel-related non-varicose nerve fibres in the mesouterus. The use of different neuronal and Schwann cell markers showed that the extrinsic innervation was predominantly adrenergic and contained only few peptidergic nerves. Acetylcholinesterase-positive (cholinergic) nerves were only found around the uterine artery. In late pregnancy, the extrinsic nerves of the mesouterus adjacent to foetus-containing uterine horns underwent pronounced degenerative changes comprising both Schwann cell and axonal structures. In comparison, no changes were found in extrinsic nerves of mesouteri adjacent to non-foetus-bearing uterine horns or in extrinsic nerves in the suspensory ligaments. Further, chemical sympathectomy produced axonal degeneration but no changes in the Schwann cells. In conclusion, the pregnancy-induced nerve degeneration is of a very special type different from that following chemical sympathectomy and represents a local phenomenon related to the conceptus. Hypothetically, this could be of importance for counteracting disturbances in placental blood flow.

Animals↗
PubMed1988

Organization of the guinea-pig uterine innervation. Distribution of immunoreactivities for different neuronal markers. Effects of chemical- and pregnancy-induced sympathectomy.

The structural organization of the guinea-pig uterine innervation was investigated by an immunofluorescence method using neurofibrillary protein (NF) and neuron-specific enolase (NSE) as general neuronal markers. NF- and NSE-immunoreactive nerve trunks and non-varicose nerves formed continuous networks similar to nerves with analogue morphology and with immunoreactivities for tyrosine hydroxylase (TH; adrenergic nerves) and neuropeptide Y (NPY). NF- and NSE-immunoreactive non-varicose nerves occurred in the myometrium and along vessels, where TH- and NPY-immunoreactive varicose nerves were also comparatively frequent. After chemical sympathectomy all TH- and NPY-immunoreactive varicose nerves and most NF- and NSE-immunoreactive non-varicose nerves disappeared, suggesting colocalization of TH, NPY, NF and NSE immunoreactivities. During pregnancy all NF-, NSE-, TH- and NPY-immunoreactive nerve structures disappeared in the foetus-bearing uterine horns whereas in the cervix and non-foetus-bearing uterine horns only the myometrial TH- and NPY-immunoreactive varicose nerves disappeared. After parturition there was a complete structural restoration of all types of immunoreactive nerves in previously non-foetus-related tissue. The reinnervation of this tissue followed a similar time-course to that after chemical sympathectomy. In contrast, the reinnervation of previously foetus-related tissue was much slower and incomplete. In conclusion, the whole autonomic uterine innervation undergoes overt structural changes during pregnancy and these changes are related to the foetus-bearing regions.

Adrenergic Fibers↗