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Biomedical subjects

C Baldwin

Publications and source records attributed to C Baldwin.

At least 55 records · Page 3Linked to original sources
PubMed1991

Distribution of vasoactive intestinal peptide- and peptide histidine isoleucine amide-like immunoreactive neurons and fibers in the thoracic spinal cord of the rat.

The distributions of vasoactive intestinal peptide (VIP)- and peptide histidine isoleucine amide (PHI)-immunoreactivities (IR) in the thoracic spinal cord of the rat are described. VIP- and PHI-IR were present in cells and fibers in the lateral spinal nucleus, lamina VII, nucleus proprius, substantia gelatinosa, intermediolateral cell column, and the area around the central canal. The functions of these peptides in the thoracic spinal cord are not known; however, their locations suggest that they are involved in sensory and autonomic functions, among others.

Animals↗
PubMed1991

Evidence that some preganglionic sympathetic neurons in the rat contain vasoactive intestinal peptide- or peptide histidine isoleucine amide-like immunoreactivities.

Physiological studies have established that preganglionic sympathetic nerve fibers innervating the rat superior cervical ganglion release a second transmitter, in addition to acetylcholine. Based on pharmacological and histochemical investigations, possible candidates for this non-cholinergic neurotransmitter include vasoactive intestinal peptide and peptide histidine isoleucine amide. For example, previous immunohistochemical studies have demonstrated that antisera raised against both of these peptides stain neural processes in the rat preganglionic cervical sympathetic trunk and in the superior cervical ganglion. In the present study, it was found that, when the cervical sympathetic trunk was ligated, vasoactive intestinal peptide- and peptide histidine isoleucine amide-like immunoreactivities built up on both sides of the ligature. In addition, examination of the thoracic spinal cord in colchicine-treated animals revealed vasoactive intestinal peptide- and peptide histidine isoleucine amide-like immunoreactivies in neuronal cell bodies in the intermediolateral cell column and in the region of the lateral funiculus adjacent to it. In a second group of animals in which retrograde tracing techniques were used, these two regions of the spinal cord were shown to contain most of the cell bodies of the preganglionic neurons that project to the superior cervical ganglion. Smaller numbers of retrogradely labeled neurons were found dorsal to the central canal and in the nucleus intercalatus. When either vasoactive intestinal peptide- or peptide histidine isoleucine amide-like immunostaining and retrograde labeling were examined in the same animals, double-labeled neurons were found in the intermediolateral cell column and in the lateral funiculus. These data demonstrate that vasoactive intestinal peptide- and peptide histidine amide-like immunoreactivities are present in certain of the preganglionic neurons that project to the superior cervical ganglion, supporting the hypothesis that vasoactive intestinal peptide and peptide histidine isoleucine amide are released in the ganglion when these preganglionic neurons are activated.

Animals↗
PubMed1991

Circulating filarial antigen in cats infected with Brugia pahangi is indicative of the presence of adult worms.

Using counterimmunoelectrophoresis with rabbit antisera raised against soluble extracts of adult females of Brugia pahangi parasite antigen was detected in the serum of all cats repeatedly infected with B. pahangi. Antigen was never detected in uninfected cats. The antigen was associated with the presence of adult worms. Antigen was detected consistently in a cat that was amicrofilaraemic but at autopsy harboured only two or three adult worms. Conversely, some cats showed slowly declining numbers of microfilariae and, in these, circulating antigen declined before the number of microfilariae. Eventually no antigen was detectable in circulation whereas microfilariae, although in diminishing numbers, were still present. At autopsy no adult worms were found in these cats. Antigen also appeared in several cats before they became microfilaraemic.

Animals↗
PubMed1991

Vasoactive intestinal peptide stimulates catecholamine biosynthesis in isolated adrenal chromaffin cells: evidence for a cyclic AMP-dependent phosphorylation and activation of tyrosine hydroxylase.

Vasoactive intestinal peptide (VIP) increased catecholamine biosynthesis in bovine adrenal chromaffin cells by 50-200%. Six related peptides produced no effects. In addition, VIP increased tyrosine hydroxylase (TH) activity measured in gel-filtered supernatants prepared from homogenates of treated cells. The hypothesis that cyclic AMP is the second messenger involved in these effects of VIP was also evaluated. VIP led to an elevation of cyclic AMP levels, and this increase occurred over a similar concentration range and time course as the activation of TH and the increase in catecholamine biosynthesis. Each measure reached maximal levels at 10-20 microM VIP within 1 min and remained elevated for at least 16 min. These changes produced by VIP were paralleled by enhanced phosphorylation of TH, and this phosphorylation occurred on a single tryptic peptide that was the same peptide whose phosphorylation has been previously shown to be stimulated by forskolin. In contrast to VIP and forskolin, 12-O-tetradecanoylphorbol 13-acetate, a phorbol ester known to activate protein kinase C, increased the phosphorylation on a total of three tryptic peptides of TH. Our results indicate that VIP stimulates catecholamine biosynthesis in chromaffin cells through the phosphorylation and activation of TH and support the conclusion that a cyclic AMP-dependent phosphorylation of TH is responsible for these effects.

Adrenal Glands↗
PubMed1990

Dietary intake of women runners.

One hundred and three women who were habitual distance runners and 74 age-matched physically inactive women provided three-day diet records. Intergroup differences in intakes of energy nutrients, micronutrients, cholesterol and fiber were evaluated via analysis of variance and, to assess qualitative differences, via analysis of covariance with total caloric intake entered as the covariate. Women runners reported consuming more carbohydrate (192.4 vs 165.0 g.d-1) and less fat (57.5 vs 66.1 g.d-1) than did the inactive women (p less than .05). After controlling for the non-significant intergroup difference in caloric intake, these differences persisted and protein intake was lower in the runners. Cholesterol and saturated fat intakes were lower and fiber intake was greater in the runners, with and without control for differences in caloric intake. These data suggest that female runners, when compared to inactive counterparts, tend to follow dietary practices that conform more closely to the current recommendations of health authorities.

Adult↗
PubMed1990

Intussusception of the appendix in a patient with cystic fibrosis.

This case report describes the clinical presentation and the radiographic, endoscopic, and pathologic findings in a patient with cystic fibrosis (CF) and intussusception of the appendix. This is the first time that intussusception of the appendix has been documented in a patient with CF. This disorder should be considered in the CF patient with cramping lower abdominal pain or rectal bleeding.

Adolescent↗
PubMed1990

Comparing scores on the Stanford-Binet, Fourth Edition with the WISC-R for exceptional children.

The purpose of the present study was to examine the performance of a sample of 19 exceptional children on both the Stanford-Binet Intelligence Scale, Fourth Edition (Stanford-Binet IV) and the WISC-R. Construct validity studies of the Stanford-Binet IV with the WISC-R have yielded results which provide only partial support for predictions derived from the theoretical model underlying this new measure. The results obtained for the naturally occurring sample of exceptional children indicate nonsignificant differences in performance between Stanford-Binet IV and WISC-R Full Scale IQ. As with prior studies, results provide only partial support for the predictions derived from the theoretical model. Explanatory hypotheses for the observed discrepancies are discussed.

Adolescent↗
PubMed1990

The Stanford-Binet, Fourth Edition: a small study of concurrent validity.

To date most studies of construct and concurrent validity of the Stanford-Binet Intelligence Scale, Fourth Edition, have employed an established measure of ability as the criterion. Here achievement, assessed by the Wide Range Achievement Test-Revised and the Peabody Individual Achievement Test, was the criterion for establishing concurrent validity. The sample consisted of a naturally occurring group of 21 children referred for learning difficulties. The results provided partial support for the theoretical model of the Stanford-Binet IV. Intercorrelations among individual Stanford-Binet IV and achievement subtest scores were examined to generate explanatory hypotheses for those predictions which were not empirically supported. Finally, correlations between the WISC-R and the achievement measures were compared with those between the Stanford-Binet IV and the achievement measures. Examination shows that the correlations of the Stanford-Binet IV with achievement are as strong as and sometimes stronger than those between the WISC-R and achievement.

Achievement↗
PubMed1988

Amino acid sequence of the triple-helical domain of human collagen type VI.

The complete amino acid sequence of the triple-helical domain of human collagen VI was deduced from sequences of appropriate cDNA clones and confirmed to about 50% by Edman degradation of tryptic peptides. This domain consists of three different peptide segments containing some 335-336 amino acid residues originating from central portions of the alpha 1 (VI), alpha 2(VI), and alpha 3(VI) chains, respectively. Sequence identity in the X/Y positions of the Gly-X-Y repeats is rather low (10-15%) between the chains. Peculiar features of these sequences include 3 cysteine residues about 50 (alpha 3(VI)) and 89 (alpha 1(VI), alpha 2(VI)) residues away from the N-terminus and several Gly-X-Y interruptions clustered in the C-terminal two-thirds of the triple helix. These structures are presumably required for cross-linking collagen VI oligomers and for super-coiling of triple helices in the dimers. Other features include 11 Arg-Gly-Asp sequences, some of which are likely to be used as cell-binding sites, and four Asn-X-Thr sequences, allowing N-linked glycosylation along the triple helix. Junctional areas close to the helix contain short, cysteine-rich segments which may seal the triple-helical domain through disulfide bond formation, endowing it with high stability. These features, together with a low sequence homology to fiber-forming and basement-membrane collagens, document the unique character of collagen VI, whose triple helix is specifically adjusted for forming microfibrils in tissues.

Amino Acid Sequence↗
PubMed1985

Regulation of the concentration of adenosine 3',5'-cyclic monophosphate and the activity of tyrosine hydroxylase in the rat superior cervical ganglion by three neuropeptides of the secretin family.

Preganglionic nerve stimulation leads to an acute elevation of tyrosine hydroxylase (TH) activity in the rat superior cervical ganglion. This effect is mediated in part by acetylcholine, acting via nicotinic receptors, and in part by a noncholinergic neurotransmitter. As a first step in an attempt to identify this noncholinergic transmitter, we have examined a number of biogenic amines, purine nucleotides, neuropeptides, and other compounds for their ability to increase TH activity. Secretin, vasoactive intestinal peptide (VIP), and PHI (a 27-amino acid peptide with an NH2-terminal histidine and a COOH-terminal isoleucine amide), all members of the secretin family of peptides, increased TH activity acutely. Human pancreatic growth hormone-releasing factor, glucagon, and gastric inhibitory peptide (three other members of this peptide family) and all other transmitter candidates tested had no effect on this enzyme activity. We have examined the possibility that this peptidergic regulation of TH activity is mediated via changes in adenosine 3',5'-cyclic monophosphate (cAMP) levels. When the six members of the secretin family were tested for their ability to increase cAMP levels in the ganglion, secretin, VIP, and PHI significantly increased this cyclic nucleotide, whereas growth hormone-releasing factor, glucagon, and gastric inhibitory peptide produced no significant effects. The rank orders of potency and of efficacy of secretin, VIP, and PHI in altering TH activity and cAMP levels were identical. Furthermore, a strong correlation was found between the cAMP level and the TH activity in individual ganglia exposed to these peptides. Finally, 8-bromoadenosine 3',5'-cyclic monophosphate and forskolin also increased TH activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Rapid recovery of pineal function after partial denervation: a possible role for heteroneuronal uptake of transmitter in modulating synaptic efficacy.

The pineal gland is innervated by sympathetic neurons whose cell bodies are located in the two superior cervical ganglia and whose axons reach the gland via the two internal carotid nerves (ICNs). Bilateral decentralization of the superior cervical ganglia, produced by lesioning both cervical sympathetic trunks (CSTs), abolishes the circadian rhythm in the activity of the pineal enzyme serotonin N-acetyltransferase (NAT). We have examined the effects on NAT activity of unilaterally cutting the ICN or the CST. During the first night after either operation, nocturnal NAT activity was reduced by 75% compared to controls. However, during the second night after unilaterally cutting the ICN, NAT activity was restored to control values, and normal enzyme activity was seen in these lesioned animals for up to 1 month after this operation. On the other hand, following unilateral decentralization of one superior cervical ganglion, enzyme activity was reduced for at least 5 months. The high enzyme activity in animals with one ICN cut was abolished by cutting the contralateral CST, indicating that the recovery of NAT activity depended on the remaining intact sympathetic neurons. Electrical stimulation of the intact ICN during the daytime in animals in which the contralateral ICN was cut produced an increase in pineal NAT activity which was greater than the increase seen when similar stimulation was performed in sham-operated animals or in animals in which the contralateral superior cervical ganglion had been decentralized. The time course of the recovery of nocturnal NAT activity after unilateral denervation of the pineal gland was similar to the time course of the decrease in norepinephrine uptake sites in the gland.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Sympathetic reinnervation of the pineal gland after postganglionic nerve lesion does not restore normal pineal function.

The activity of the enzyme serotonin N-acetyltransferase (NAT) in the rat pineal gland exhibits a large circadian rhythm, with peak activity occurring at night. This rhythm is dependent on stimulation of the pineal gland by neurons whose cell bodies are in the superior cervical ganglia and whose axons reach the gland via the internal carotid nerves (ICNs). Two days after both ICN were cut, crushed, or frozen, nighttime NAT activity was decreased by 90%. The remaining low level of enzyme activity was not affected by decentralization of the superior cervical ganglia. Thus, this enzyme activity did not depend on the activity of neurons in these ganglia. Bilaterally lesioning the ICN also abolished the neuronal uptake of norepinephrine in the pineal, further indicating that the sympathetic innervation of the gland had been destroyed. Three months after crushing both ICNs, nighttime NAT activity was only 20% of control values. However, in these animals, bilateral decentralization of the superior cervical ganglion reduced this low level of NAT activity by 90%. Thus, NAT activity, although low, was again dependent on sympathetic nerve stimulation. In contrast to this rather small recovery of nocturnal NAT activity, the norepinephrine uptake capacity of the gland recovered to 60% of control values. A similar discrepancy between the extent of recovery of NAT activity and of norepinephrine uptake was observed when the ICNs were frozen rather than crushed. To determine to what extent the sympathetic nerves that had reinnervated the pineal gland in these lesioned animals were capable of regulating NAT activity, their cervical sympathetic trunks were stimulated electrically at 5 Hz for 3 hr during the daytime.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetyltransferases↗
PubMed1983

The evaluation of neutropenia: the use of the granulocyte mobilization test.

Ten individuals with idiopathic neutropenia and similar numbers of normal and abnormal controls were tested for mobilization of their marginal granulocyte pools and bone marrow reserve by using epinephrine and hydrocortisone intravenously. Individuals with 'benign' idiopathic neutropenia appeared to have a normal response while half the abnormal controls responded poorly. It is suggested that granulocyte mobilization tests are valuable in the assessment of individuals with neutropenia.

Adult↗
PubMed1983

Mycoplasma gateae arthritis and tenosynovitis in cats: case report and experimental reproduction of the disease.

Polyarthritis and tenosynovitis were diagnosed in a cat. Clinical signs of 2 months' duration included swollen limbs, painful joints (sensitive to touch), lameness, and pyrexia. Laboratory test data revealed hypogammaglobulinemia, hypoalbuminemia, leukocytosis, and mild anemia. The cat was euthanatized and necropsied; there were chronic necrotizing fibrinopurulent tenosynovitis and arthritis with bone and cartilage erosions. Cultural examinations of synovia were positive for Mycoplasma gateae, but bacterial and viral cultural examinations were negative. Organisms propagated from the M gateae isolate were inoculated IV into 6 specific-pathogen-free cats--3 of these being subjected to immunosuppression induced with azathioprine. The 6 inoculated cats became lame 5 to 9 days later, and 5 became febrile. Cultural examinations of the pharynx in 4 cats were positive for M gateae and in 3 cats, the organism was isolated from various joints. Microscopically, arthritis and tenosynovitis were identified in all cats. Two specific-pathogen-free cats were used as controls (noninoculated); these did not become lame, had negative M gateae cultures, and were free of histopathologic abnormalities. Reproduction of disease with recovery of the causative agent indicates the pathogenicity of this particular isolate of M gateae in the cat when inoculated IV.

Animals↗
PubMed1982

Mechanisms of sulphur dioxide induced bronchoconstriction in normal and asthmatic man.

We have examined the inhibitory effect of atropine and sodium cromoglycate (SCG) on the bronchial response to sulphur dioxide (SO2) in groups of normal and asthmatic subjects. Eleven normal subjects were premedicated with propranolol (100 mg orally) one hour before each experiment. After baseline measurements of specific airways conductance (sGaw) the subject inhaled an aerosol from a Wright nebuliser for five minutes. In separate experiments this contained water (control), atropine methonitrate (0 . 2%), or SCG (1%). Fifteen minutes later sGaw was remeasured and the subject then breathed SO2 (8 ppm) for three minutes through the mouth. Specific airways conductance was measured for the duration of the subsequent response. Intervals between experiments on any one subject were one week or more. After control SO2 inhalation sGaw decreased in all subjects (mean 34 +/- 17 (SD)%). Atropine and SCG significantly inhibited the SO2 response (p less than 0 . 01 for both). After atropine the mean decrease in sGaw was 13 +/- 24%; after SCG 16 +/- 12% (range -3- + 55%). With atropine the degree of inhibition was inversely related to the subject's responsiveness to the control SO2 inhalation (r = 0 . 75; p less than 0 . 01). In four asthmatics (without beta-blockade and with lower SO2 exposure) atropine did not inhibit the SO2 response; SCG had a similar effect to that seen in normal subjects. Therefore, vagal efferent mechanisms are involved in the bronchial response to SO2 in normal subjects, but the lack of inhibition caused by atropine in hyperreactive normal and asthmatic subjects suggests that vagal mechanisms are not important in the causation of hyperreactivity to SO2. The mechanism of inhibition with SCG is unknown.

Adult↗
PubMed1981

Rapid recovery of function after partial denervation of the rat pineal gland suggests a novel mechanism for neural plasticity.

The activity of serotonin N-acetyltransferase (NATase) in the rat pineal gland exhibits a large (approximately 100-fold) circadian variation, with peak activity occurring in the dark part of the light/dark cycle. Surgical removal of both superior cervical ganglia abolishes this rhythm in enzyme activity. Unilateral ganglionectomy caused a 75% decrease in NATase activity during the dark period immediately following the operation; however, by the subsequent dark period (32 hr after operation) the rhythm in NATase activity had returned to normal. Similar results were found after the internal carotid nerve was cut, and data are presented indicating that this is the postganglionic trunk by which sympathetic neurons reach the pineal gland. Denervation of one superior cervical ganglion (unilateral "decentralization") also produced a 75% decrease in NATase activity during the dark period immediately following the operation; however, after decentralization, enzyme activity did not return to normal in subsequent cycles. It is hypothesized that this recovery is due to loss of norepinephrine uptake sites in the degenerating sympathetic nerve terminals. As a result of decreased norepinephrine uptake, the effectiveness of the norepinephrine released by surviving neurons may be enhanced. This hypothesis is supported by experiments in which pharmacological blockade of norepinephrine uptake in unilaterally decentralized animals increased NATase activity to control levels. We propose that neural systems which use transmitter uptake as the mechanism of transmitter inactivation have a built-in "reserve stimulatory capacity."

Acetyltransferases↗