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Biomedical subjects

C Shaw

Publications and source records attributed to C Shaw.

At least 289 records · Page 16Linked to original sources
PubMed1990

Malignancies metastatic to the pleura.

In patients over 50 years of age, neoplasms of the pleura are probably the second most common cause of a pleural effusion after congestive heart failure. Lung cancer, breast cancer, lymphoma, ovarian carcinoma, and stomach cancer are the leading causes of malignant pleural disease, and adenocarcinoma is the most common cell type. This review discusses in detail the etiology and incidence, pathogenesis, clinical manifestations, diagnosis, prognosis, and treatment of neoplasms that involve the pleura with special reference to malignant and paramalignant pleural effusions.

Humans↗
PubMed1990

Vasoactive intestinal peptide (VIP) and peptide histidine methionine (PHM) in human eccrine sweat glands: demonstration of innervation, specific binding sites and presence in secretions.

Vasoactive intestinal peptide (VIP) and peptide histidine methionine (PHM) immunoreactivities have been detected in alcohol extracts of human axillary skin using sensitive and specific radioimmunoassays. VIP immunoreactivity (7.63 + 2.33 pmol/g, x + SE, n = 9) was more abundant than PHM immunoreactivity (3.86 + 0.56 pmol/g, x + SE, n = 9). Immunocytochemistry of sections of skin revealed a network of VIP/PHM immunoreactive nerve fibres around the perimeter of eccrine but not apocrine sweat glands. In vitro autoradiography of skin sections using 125I-labelled VIP and PHM, demonstrated binding sites on the membranes of eccrine gland secretory cells. The binding of each radiolabelled ligand was eliminated by the presence of a large molar excess of appropriate cold peptide but was unaffected when incubated with related peptide, indicating the presence of specific binding sites for both VIP and PHM. Radioimmunoassay of Sep-pak concentrated human sweat identified the presence of both VIP immunoreactivity (30.6 pmol/l) and PHM immunoreactivity (43.4 pmol/l). Reverse-phase HPLC analysis of axillary skin extracts and sweat, followed by radioimmunoassay of fractions, identified single resolved peaks of VIP and PHM immunoreactivity with identical retention times to synthetic standards. Eccrine sweat glands in human axillary skin have VIP and PHM peptidergic innervation and possess specific binding sites for each peptide which are both secreted to the surface of the skin.

Binding Sites↗
PubMed1990

Beta-adrenergic stimulation of cyclic AMP is defective in cultured dermal fibroblasts of psoriatic subjects.

Epidermal cells from psoriatic lesions demonstrate a very low cAMP response to beta-adrenergic stimuli. We have shown that a similar abnormality occurs in dermal fibroblasts from affected areas of skin. The cells, after 5-12 passages in tissue culture, had a much reduced response to 10(-8) M and 10(-6) M isoproterenol when compared with fibroblasts from control subjects. The abnormality was not abolished by the addition of the phosphodiesterase inhibitor, 3-isobutyl-I-methylxanthine. Other putative agonists tested were vasoactive intestinal peptide and peptide histidine methionine. Neither of these had an effect on dermal fibroblasts from either normal controls or from lesions of psoriasis.

1-Methyl-3-isobutylxanthine↗
PubMed1990

Effects of exercise training in the elderly on the occurrence and time to onset of cardiovascular diagnoses.

To examine the long-term effects of aerobic exercise on the occurrence and time to onset of cardiovascular diagnoses, 184 initially healthy older subjects were randomized into either a long-term exercise group (Group A, n = 80), a short-term exercise group (Group B, n = 42), or a contract control group (Group C, n = 62). After completion of two years in the study, data on new cardiovascular diagnoses and time to onset of these diagnoses in each of the three groups were compared. The occurrence rates for new onset diagnoses were as follows: Group A, 2.5%; Group B, 2%; and Group C, 13%; the average time to onset was greatest for the long-term exercisers and shortest for the contact control group (P less than or equal to .02). The results suggest that a regular program of exercise may have cardiovascular benefits for those over 60 years of age.

Aged↗
PubMed1990

Sandostatin and the Belfast experience.

Twenty-four patients with 26 apudomas have been treated with Sandostatin (octreotide) in Belfast. The 2 patients with vipoma showed an excellent response clinically and biochemically. Of 15 patients with carcinoids, Sandostatin improved the diarrhoea in 70%, flush in 58%, and wheeze in 100% of patients. Patients with insulinoma and the Zollinger-Ellison syndrome were unresponsive to Sandostatin. In general, the response to Sandostatin appeared to decline as the tumour size increased and tumour markers rose. Side effects have not been a problem.

Apudoma↗
PubMed1990

The effect of the steroidal androgen receptor antagonist, Win 49,596, on the prostate and testis of beagle dogs.

The effect of the steroidal androgen receptor antagonist Win 49,596 on the prostate and testis was studied in beagle dogs and was compared to the effects of the nonsteroidal androgen receptor antagonist ICI 176,334 and the steroidal 5 alpha-reductase inhibitor MK-906. Win 49,596 was shown to bind to the androgen receptor from normal canine prostate with a Ki of 2.2 microM. After 16 weeks of treatment, prostate size, as estimated by transrectal ultrasonography, was unchanged in intact controls and was 26% of the initial size in castrate controls. Oral doses of Win 49,596 from 0.625-40 mg/kg.day for 16 weeks caused dose-dependent prostatic regression and a dose-related increase in both the incidence and severity of glandular atrophy of the prostate. Prostatic secretory function was also inhibited by Win 49,596 treatment. The effects of Win 49,596 at 40 mg/kg.day on prostatic weight, total DNA, histomorphology, and secretory function were similar to those of castration, while the effects of Win 49,596 at 10 mg/kg.day were similar to those of ICI 176,334 at 0.25 mg/kg.day and MK-906 at 1.0 mg/kg.day. No effects on testicular weight, daily sperm production, or spermatogenesis were observed; however, mild Leydig cell hyperplasia was observed in two dogs treated with 40 mg/kg.day Win 49,596. In addition, at 10 and 40 mg/kg.day Win 49,596, moderate but variable increases in serum testosterone levels were observed. In summary, Win 49,596 caused regression of the hypertrophic canine prostate without effects on spermatogenesis and/or sexual function, supporting its possible use in the treatment of human benign prostatic hypertrophy/hyperplasia.

5-alpha Reductase Inhibitors↗
PubMed1989

Localization, quantification, and characterization of pancreatic polypeptide immunoreactivity in the parasitic flatworm Diclidophora merlangi and its fish host (Merlangius merlangus).

Pancreatic polypeptide (PP) immunoreactivity (IR) has been identified, quantified, and subsequently chemically characterised in the parasitic platyhelminth, Diclidophora merlangi, and its specific teleostean host the whiting, Merlangius merlangus. Immunocytochemistry demonstrated PP-IR throughout the central and peripheral nervous systems of the parasite and in open-type endocrine cells of the gastric mucosa of its host. Radioimmunoassay detected PP-IR in alcoholic extracts of whole parasites (39.2 ng/g) and in extracts of gastrointestinal tract (2.1 ng/g), brain (4.6 ng/g), and pancreas (12 ng/g) of the host. Chromatographic analysis of parasite extracts revealed a single immunoreactive species of PP in both high-performance gel permeation and reverse-phase systems. The molecular size of this peptide was similar to bovine PP standard. In contrast, whiting tissues contained two immunoreactive species of PP in both gel permeation and reverse-phase systems. The major species was similar in size to bovine PP standard and the minor species was smaller, with a molecular size comparable to bovine neurotensin. Reverse-phase HPLC revealed that parasite and host peptides were not identical.

Animals↗
PubMed1989

Immunocytochemical demonstration of neuropeptides in the fish-gill parasite, Diclidophora merlangi (Monogenoidea).

Using the indirect immunofluorescence technique, immunoreactivity (IR) to three mammalian and one invertebrate regulatory peptide has been demonstrated in the nervous system of the monogenean gill parasite Diclidophora merlangi. IR to pancreatic polypeptide (PP), peptide tyrosine tyrosine (PYY) and FMRFamide was evident throughout central and peripheral nervous tissues, whereas vasoactive intestinal polypeptide (VIP)-IR was confined to a portion of the longitudinal ventral nerve cords. Staining patterns revealed the orthogonal arrangement of the nervous system consisting of paired cerebral ganglia, connecting post-pharyngeal commissure, three pairs of longitudinal nerve cords and associated neurones. PP-IR, PYY-IR and FMRFamide-IR were intense throughout the central nervous system of the worm. A small plexus of nerve fibres and somata in each peduncle was immunoreactive for FMRFamide and provided innervation to each of the eight posterior clamps. In the peripheral nervous system, PP-IR, PYY-IR and FMRFamide-IR occurred in an extensive nerve-net with fine, possibly sensory nerve endings in the tegument. PP-IR was also present in nerve fibres in the walls of the ootype, seminal vesicle and uterus. PYY- and FMRFamide-IRs, while evident in nerve fibres of the ootype wall, were also present in a distinct population of cells that encircles the ootype, and which are linked to it by fine cytoplasmic connectives. The majority of these somata were bipolar or multipolar. PYY-IR and FMRFamide-IR were also associated with nerve fibres and bipolar cells in the wall of the vitelline reservoir. Regulatory peptides would appear to play an integral role in neuronal functioning and egg development in D. merlangi.

Animals↗
PubMed1989

Characterization of muscarinic acetylcholine receptors in rat cerebral cortex slices with concomitant morphological and physiological assessment of tissue viability.

We have begun studies on regulatory mechanisms of muscarinic acetylcholine receptors (mAChRs) in slices of rat cerebral cortex. This paper, the first of two, deals with the viability of the cells in the slices (a prerequisite for studying receptor regulation) and provides a characterization of binding sites for [3H]N-methyl scopolamine ([3H]NMS) and [3H]quinuclidinyl benzylate ([3H]QNB) in this preparation. Trypan blue exclusion tests in 400-microns-thick cortical slices showed a number of dead cells in a 100 microns zone from each cut edge, for a total of about 15-30% of all cells in the slice. In agreement with previous reports, electron microscopy revealed healthy tissue in the middle of the slice, but after incubation for several hours, swollen cells and dendrites were seen without cytoplasmic organelles. Axon terminals, however, were still seen to synapse upon these processes. Electrophysiological single unit recordings showed spontaneous action potentials in the slices. For receptor binding experiments, slices were incubated with either [3H]NMS, a hydrophilic mAChR ligand which does not penetrate the cell membrane, or the lipophilic ligand [3H]QNB which readily enters cells. For both ligands, equilibrium binding was reached after 8 h at 4 degrees C, and after 3 h at 30 degrees C. Binding of both ligands could be displaced by unlabelled atropine sulphate, NMS or QNB. Saturation binding curves yielded a Bmax of 2187 fmol/mg protein for [3H]QNB (reflecting all mAChRs) and 1335 fmol/mg protein for [3H]NMS (only mAChRs on the cell surface) at 30 degrees C. Kd values were 8.2 and 5.2 nM for [3H]QNB and [3H]NMS, respectively. These values are high compared with values obtained from homogenates, frozen sections or dissociated cells, and presumably reflect the use of intact, living tissue. These data are probably a better reflection of the actual, in vivo mAChR number and affinity than those obtained from dead tissue. This slice preparation suggests itself as a simple but effective method with which to study the regulation of mAChRs in living brain tissue.

Animals↗
PubMed1989

A role for potassium channels in the regulation of cortical muscarinic acetylcholine receptors in an in vitro slice preparation.

The rules underlying muscarinic acetylcholine receptor (mAChR) regulation in an in vitro cortical slice preparation of adult rats were examined following various alterations of bioelectric activity and following agonist stimulation. Muscarinic ACh antagonists [3H]N-methyl scopolamine ([3H]NMS) or [3H]quinuclidinyl benzylate ([3H]QNB) were used to label cell surface vs total (i.e. surface and internal) receptors, respectively. Depolarization of neural membranes for 4 h at 22-37 degrees C using veratridine or high external potassium (K+) led to a temperature-dependent down-regulation of surface mAChR of 26.2% and 11.3%. Total mAChRs decreased by 37.6% and 8.1%. Addition of picrotoxin and glutamic acid also led to decreases in mAChRs. Increases in inward chloride ion current induced by gamma-aminobutyric acid (GABA) or gold chloride had no significant effect on mAChRs. Blockade of calcium channels and synaptic transmission by magnesium or cobalt and postsynaptic calcium channels with nifedipine showed a significant effect on mAChRs only in the latter case. In contrast, agonist stimulation using carbachol led to a large down-regulation for both [3H]NMS and [3H]QNB (26.1%, 35.9%). ACh decreased [3H]QNB binding by 33.9%, but had little effect on [3H]NMS binding (6.3%). For [3H]QNB binding sites the effects of carbachol appeared to summate with those of veratridine. Down-regulation of [3H]NMS labelled mAChRs by carbachol and veratridine had an estimated half-time of 30 min and 2 h, respectively. Neither the effects of veratridine nor carbachol could be antagonized by tetrodotoxin (TTX), showing that the effects were not due to an increase in sodium ion currents. However, a common thread linking the various agents which induce mAChR down-regulation appears to involve changes in potassium (K+) current. Potassium channel blockers tetraethylammonium chloride (TEA), 4-aminopyridine (4-AP) and apamin had little independent effect on mAChR number, but prevented veratridine-induced down-regulation, presumably through a blockade of K+- and Ca2+-dependent K+-channels. Only TEA and 4-AP diminished carbachol-induced down-regulation suggesting that this effect involves only the non Ca2+-dependent K+-channels. It thus appears that mAChR regulation in the rat cerebral cortex is linked to changes in active K+-channel currents: activation of the K+-channel by depolarization-induced changes in K+ current or by agonist stimulation leading to changes in the selective K+ currents stimulate mAChR down-regulation; blockage of the K+-channels prevents this down-regulation.

4-Aminopyridine↗
PubMed1989

Phorbol 12,13-dibutyrate regulates muscarinic receptors in rat cerebral cortical slices by activating protein kinase C.

Stimulation of muscarinic acetylcholine receptors (mAChR) elicits phosphatidylinositol turnover, which yields inositol phosphates (InsP) and diacylglycerol (DG) the latter activating protein kinase C (PKC). Activating PKC with phorbol esters inhibits mAChR agonist-stimulated phosphoinositide hydrolysis and InsP production. A possible mechanism of this inhibition may be down-regulation of mAChR by PKC. In the present work, rat cortical slices were preincubated with phorbol 12,13-dibutyrate (PDBu) followed by binding assays for [3H]quinuclidinyl benzilate [( 3H]QNB), [N-methyl-3H]scopolamine [( 3H]NMS) or [3H]pirenzepine [( 3H]PZ). Our data demonstrate that activation of PKC by phorbol esters causes a rapid down-regulation of muscarinic cholinergic receptors. This down-regulation is also rapidly reversible. Receptors on the cell surface appear to be more sensitive to the effect of PKC than do internal ones. This down-regulation occurs by a decrease in the number of receptors, rather than by changes in receptor affinity. The results suggest that PKC may exert negative feedback on its own activation by down-regulating the receptors that normally elicit phosphatidylinositol turnover.

Animals↗
PubMed1989

Differential effects of quinolinic acid lesions on muscarinic acetylcholine receptors in cat visual cortex during postnatal development.

Quinolinic acid (QA) lesions of neurons in cat visual cortex were combined with conventional in vitro autoradiographic methods in order to define the cellular locus of the muscarinic acetylcholine receptor (mAChR). Animals of various postnatal ages had QA unilaterally injected into the visual cortex. Four to fourteen days later they were sacrificed and processed for electron microscopy (EM) or in vitro autoradiography. QA lesions at the various postnatal ages were found to eliminate intrinsic cortical neurons and their processes while leaving intact glia, fibers of passage and axon terminals from outside the lesion zone. Autoradiograms of visual cortex labelled with [3H]QNB (which labels M1 and M2 subtypes) showed an age-dependent loss of binding sites, with the greatest decreases occurring after 65 days postnatal. Examined separately, only the M1 mAChRs labelled with [3H]pirenzepine exhibited these age-dependent alterations. The results indicate a differential distribution of the M1 mAChRs during postnatal development. The loss of receptors late in postnatal life following QA suggests a dominantly neuronal locus; the relatively small loss early in postnatal life suggests a locus on other cellular elements.

Aging↗
PubMed1989

Tachykinin immunoreactivity in the parasitic flatworm Diclidophora merlangi and its fish host the whiting (Merlangius merlangus): radioimmunoassay and chromatographic characterisation using region-specific substance P and neurokinin A antisera.

1. Tachykinin immunoreactivity has been quantified and chemically characterised in extracts of the monogenean parasite, Diclidophora merlangi and its fish host, Merlangius merlangus, by means of four tachykinin radioimmunoassays interfaced with gel permeation chromatography and reverse-phase HPLC. 2. Of the two tachykinins identified in parasite tissue, one was SP-like and the other was NKA-like, although neither was identical to previously identified tachykinins. 3. Three tachykinins were identified in extracts of whiting GI tract, one of which was a neuropeptide and also occurred in whiting brain. 4. The parasite and fish tachykinins had different molecular weights and elution profiles in HPLC analyses, and were therefore chemically distinct.

Amino Acid Sequence↗
PubMed1989

Immunocytochemical demonstration of neuropeptides in the nervous system of the liver fluke, Fasciola hepatica (Trematoda, Digenea).

The localization and distribution of neuropeptides in the nervous system of the liver fluke, Fasciola hepatica at different stages in the development of the adult fluke have been determined by an indirect immunofluorescence technique, using antisera to 19 vertebrate peptides and the invertebrate neuropeptide, FMRFamide. Positive immunoreactivity was obtained with antisera to pancreatic polypeptide (PP), peptide tyrosine tyrosine (PYY), substance P (SP) and FMRFamide. Cell bodies and nerve fibres immunoreactive to the 4 peptides are present in the anterior ganglia and the 3 pairs of longitudinal nerve cords and their commissures in the central nervous system. In the peripheral nervous system, immunoreactivity occurs in the nerve plexuses supplying the subtegumental musculature, the oral and ventral suckers, and the muscular lining of the male and female reproductive ducts, including the ootype, uterus, cirrus pouch and gonopore. Cells displaying immunoreactivity to PYY and FMRFamide lie amongst the Mehlis' gland cells that surround the ootype. Processes from these cells extend into the wall of the ootype. One group of PP-immunoreactive cells occurs at the junction of the vitelline and ovovitelline ducts, whilst another group is situated at the entrance to the uterus from the ootype. The results are discussed in relation to the possible roles of the peptides in the neurophysiology and egg production of the fluke.

Animals↗
PubMed1989

WHO's European member states look at quality assurance. Report on the technical discussions at the thirty-eighth session of the Regional Committee for Europe.

This paper is the report on the technical discussions on "Quality assurance of health services" at the 38th session of the WHO Regional Committee for Europe, one of the activities aiming at achieving WHO's regional health for all target 31, which requests WHO's Member States to establish a quality assurance mechanism. Attended by national health authorities and experts in quality assurance, the technical discussions identified the European context for developing quality assurance and looked at national initiatives. Having agreed that the question is no more, "Is there a need for quality assurance of health services?" but, "How can it best be carried out?", the participants identified a range of quality assurance activities at national and international levels, including national strategies and financial incentives, criteria for clinical practice, information systems and coordination and management mechanisms. The report concludes with recommendations for Member States on, for example, inclusion of quality assurance in national health policies, dissemination of information, research on quality assurance, information systems and role of professional organizations.

Europe↗
PubMed1989

Superior sulcus tumors: the role of imaging.

Advances in the treatment of stage 0 to III superior sulcus tumors mandate greater accuracy in establishing tissue diagnosis, assessing tumor extent, and staging. Currently, this is best accomplished by a combination of PA chest radiography, MRI, and needle biopsy. MRI is superior to other single imaging modalities for the overall assessment of local tumor extent, bone invasion, mediastinal invasion, and perhaps in the future, determining radiosensitivity. In patients with superior sulcus tumors, evaluation of the brain, liver, and skeleton for metastases may be advisable prior to treatment with preoperative radiation and radical surgical resection.

Diagnostic Imaging↗