Biomedical subjects

C R Anderson

Publications and source records attributed to C R Anderson.

At least 37 records · Page 2Linked to original sources

PubMed1995

Characterisation of neurons with nitric oxide synthase immunoreactivity that project to prevertebral ganglia.

Retrograde dye tracing was combined with immunohistochemistry to determine the distributions of nitric oxide synthase (NOS) immunoreactive nerve cells that project to prevertebral ganglia from the gastrointestinal tract and spinal cord of the guinea pig. An antiserum was raised against the neuronal form of NOS by selecting an amino-acid sequence specific to this form as immunogen. The antiserum recognised a single band at 150 kDa on Western blots of rat brain extract. Enteric nerve cells that were labelled by Fast Blue injected into the coeliac ganglion were not NOS immunoreactive in the small intestine, whereas 40-70% were reactive in the large intestine. Retrograde dye injected into the inferior mesenteric ganglion labels cells in the colon and rectum; 60-70% were immunoreactive for NOS. The NOS-immunoreactive nerve fibres arising in the intestine appear to end selectively around somatostatin-immunoreactive nerve cells in the coeliac and inferior mesenteric ganglia. Preganglionic nerve cell bodies in the intermediolateral column and dorsal commissural nucleus from T12 to L2 were labelled from the inferior mesenteric ganglion. Nearly 70% of neurons at each level were NOS immunoreactive. Thus, two sources of NOS terminals in prevertebral ganglia have been identified, intestinofugal neurons of the large, but not the small intestine, and sympathetic preganglionic neurons.

Amidines↗

PubMed1995

Solitary kidney and sports participation.

A questionnaire was sent to the 1994 membership of the American Medical Society for Sports Medicine to describe attitudes regarding allowance of sports participation for athletes with a single kidney. Using a hypothetical scenario of a high school or collegiate preparticipation examination, the respondents were asked if they would preclude or allow participation in collision and contact sports for an athlete with a single kidney. Of 438 respondents, 237 (54.1%) indicated that they would allow full participation in sports after discussion of the possible risks. The percentage decreased to 41.6% if the athlete was their son or daughter. These results indicate that the decision to allow participation in this situation remains controversial, but they also provide some support for those physicians who allow participation.

Athletic Injuries↗

PubMed1995

Wells' syndrome in childhood: case report and review of the literature.

We report a severe case of Wells' syndrome, or eosinophilic cellulitis, after a bee sting in a 4-year-old girl. The patient had a widespread, painful, blistering eruption that was subsequently complicated by Pseudomonas aeruginosa superinfection and septicemia, hypoalbuminemia, anemia, and neutropenia. The skin lesions responded to systemic steroid therapy. There was residual scarring alopecia of the scalp. There have been 17 previous reports of childhood Wells' syndrome. We believe that this disorder is a distinct entity that should be considered in the differential diagnosis of blistering diseases in children.

Animals↗

PubMed1995

Nitric oxide synthase and chemical coding in cat sympathetic postganglionic neurons.

Nitric oxide synthase-like immunoreactivity was found in a subpopulation of sympathetic postganglionic neurons in the cat stellate and lower lumbar ganglia. In the ganglia of other segments such cells were rare. Double staining for tyrosine hydroxylase-like immunoreactivity and nitric oxide synthase-like immunoreactivity or the reduced nicotinamide adenine dinucleotide phosphate diaphorase reaction indicated that nitric oxide synthase-like immunoreactivity and reduced nicotinamide adenine dinucleotide phosphate diaphorase reactivity was always co-localized and was confined to tyrosine hydroxylase-negative (presumably cholinergic) ganglion cells, and was present in most of them. The occurrence of nitric oxide synthase in two subpopulations of cholinergic postganglionic neurons was investigated in triple staining experiments. Presumptive sudomotor neurons have been previously defined as scattered cells containing calcitonin gene-related peptide-like immunoreactivity, usually accompanied by vasoactive intestinal peptide-like immunoreactivity: 99% of these contained nitric oxide synthase. Presumptive muscle vasodilator neurons have been previously identified as clumped cells with strong vasoactive intestinal peptide-like immunoreactivity but no calcitonin gene-related peptide-like immunoreactivity: 70% of these contained nitric oxide synthase. Sweat glands were found in the paw pad skin surrounded by varicose fibres showing calcitonin gene-related peptide-like immunoreactivity and vasoactive intestinal peptide-like immunoreactivity, confirming previous work. Such fibres also stained for nitric oxide synthase-like immunoreactivity and reduced nicotinamide adenine dinucleotide phosphate diaphorase reactivity, although their staining was relatively weaker than in the corresponding cell bodies. Varicose fibres with the same chemical coding were also found around all large and most medium and small arteries in the paw skin as well as around arteriovenous anastomoses. Fibres with the muscle vasodilator coding (vasoactive intestinal peptide-like immunoreactivity without calcitonin gene-related peptide-like immunoreactivity) were not seen in paw skin. These results suggest that nitric oxide may act as a co-transmitter (with acetylcholine, substance P, vasoactive intestinal peptide and calcitonin gene-related peptide) in sudomotor neurons and (with acetylcholine and vasoactive intestinal peptide) in vasodilator neurons. Collateral branches of sudomotor neurons may innervate skin vessels, and release vasodilator transmitters including nitric oxide to cause the vasodilatation which provides the fluid supply for sweat formation. Alternatively, separate vasodilator neurons to skin may share the same chemical code as sudomotor neurons.

Animals↗

PubMed1995

Copper-sensitive mutant of Arabidopsis thaliana.

A Cu-sensitive mutant, cup1-1, of Arabidopsis thaliana has a pattern of heavy-metal sensitivity different from that of the cad1 and cad2 mutants, which are deficient in phytochelatin biosynthesis. The latter are significantly sensitive to Cd and Hg and only slightly sensitive to Cu, whereas the cup1-1 mutant is significantly sensitive to Cu, slightly sensitive to Cd, and not more sensitive to Hg, compared to the wild type. Genetic analysis has shown that the sensitive phenotype is recessive to the wild type and segregates as a single Mendelian locus, which has been mapped to chromosome 1. Genetic and biochemical studies demonstrate that the cup1-1 mutant is not affected in phytochelatin biosynthesis or function. The sensitive phenotype of the cup1-1 mutant is associated with, and probably due to, increased accumulation of higher levels of Cd and Cu compared with the wild type. Consistent with this, a Cu-inducible, root-specific metallothionein gene, MT2a, is expressed in cup1-1 roots under conditions in which it is not expressed in the wild type. Undifferentiated cup1-1 callus tissue did not show the Cu-sensitive phenotype, suggesting that the mutant phenotype, in contrast to cad1 and cad2, is not expressed at the cellular level.

Amino Acid Sequence↗

PubMed1994

Intraperitoneal injections of Fluorogold reliably labels all sympathetic preganglionic neurons in the rat.

The ability of intraperitoneal injections of a retrograde neuronal tracer, Fluorogold, to label the entire population of sympathetic preganglionic neurones was tested with a double-labelling strategy. Animals were injected intraperitoneally (i.p.) with Fluorogold, while Fast Blue or subunit B of cholera toxin were injected into a peripheral autonomic ganglion or into the adrenal gland. Sympathetic preganglionic neurones were then examined for retrogradely transported tracers. In all cases, preganglionic neurones labelled with Fast Blue or cholera toxin also contained Fluorogold, indicating that i.p. injections of Fluorogold do reliably label the entire population of sympathetic preganglionic neurones.

Adrenal Glands↗

PubMed1993

The distribution of nitric oxide synthase-containing autonomic preganglionic terminals in the rat.

Nitric oxide synthase (NOS)-immunoreactivity was co-localised with NADPH diaphorase activity in preganglionic sympathetic neurons and in their terminals in pre- and paravertebral sympathetic ganglia. The density of NOS-containing terminals varied between ganglia. Reactive terminals were densest in the superior cervical, stellate and inferior mesenteric ganglia, where the majority of the neurons were surrounded by reactive fibres, and the coeliac and superior mesenteric ganglia, where about half the postganglionic somata were surrounded by reactive terminals. Fibres were least abundant in the pelvic ganglia and thoracic and lumbar sympathetic chain ganglia. NOS reactivity did not coincide with the distribution of calcitonin gene related peptide immunoreactivity, a marker for the terminals of NOS-containing sensory neurons in the rat. The distribution of nerve cells and terminals suggests that NOS is present in more than one functional subpopulation of sympathetic preganglionic neurons.

Amino Acid Oxidoreductases↗

PubMed1993

Subunit b of cholera toxin labels interstitial cells of Cajal in the gut of rat and mouse.

Cholera toxin subunit b was found in vivo and in vitro to label interstitial cells of Cajal in the intestine of rat and mouse. Cholera toxin-labelled interstitial cells were present in the subserosa, the myenteric plexus and the deep muscular plexus of mouse small intestine, and the deep muscular plexus only of the rat small intestine. In the large intestine of the mouse, interstitial cells were present in the subserosa and in a plexus associated with the inner surface of the circular muscle, while in the rat they were only present in the latter location. Macrophages, which were present in many of the same locations as interstitial cells, were also labelled by cholera toxin but could be distinguished from interstitial cells by their ability to take-up fluorescein isothiocyanate-labelled dextran. Labelling with subunit b of cholera toxin is a simple way of labelling interstitial cells of Cajal and which is compatible with a range of physiological and histological procedures.

Animals↗

PubMed1992

NADPH diaphorase-positive neurons in the rat spinal cord include a subpopulation of autonomic preganglionic neurons.

Preganglionic neurons in the spinal cord of the rat were labelled retrogradely with Fluoro-gold and the spinal cord stained for NADPH diaphorase. The majority of both sympathetic and sacral parasympathetic preganglionic neurons showed staining for NADPH diaphorase. NADPH diaphorase-positive neurons were located more laterally in the intermediate zone than were preganglionic neurons lacking NADPH diaphorase staining. The recent evidence that identifies NADPH diaphorase as nitric oxide synthase raises the possibility that some spinal preganglionic neurons may synthesize nitric oxide.

3,3'-Diaminobenzidine↗

PubMed1992

The mechanism and significance of pentagastrin-stimulated water intake in the pig.

The role of gastric secretion in drinking was investigated. Treatment of pigs with cimetidine (300 mg IV), which inhibits gastric secretion, did not change the level of feed or water intake, or alter the temporal relationship between eating and drinking. Gastric infusions of 0.15 M HCl (5 ml.kg-1.h-1) did not increase drinking. Pentagastrin infusion (0.05 microgram.kg-1.min-1) increased water intake in some, but not all pigs during a 1-hour infusion. Plasma protein levels increased significantly during 1-hour pentagastrin infusions (0.05 microgram.kg-1.min-1), indicating an estimated fall in blood volume of 2.5%. Captopril (1.75 mg/kg IV), which blocks the renin-angiotensin system, abolished pentagastrin-stimulated drinking. It was concluded that gastric secretion does not play a direct role in normal, periprandial drinking but that in pigs the renin-angiotensin system is involved in pentagastrin-stimulated drinking.

Animals↗

PubMed1992

Animal bites. Guidelines to current management.

Several factors need to be considered when evaluating animal bites. These include type of animal involved, specific nature of the wound, circumstances of the attack, interval between injury and treatment, and location of the bite. Of concern are direct destruction of tissue and risk of infection. Use of antibiotic prophylaxis is controversial, but most authorities agree that it is needed for hand wounds, puncture wounds, or "dirty" wounds of any type in any location. The choice of antibiotic is also controversial, but initial empirical treatment generally relies on broad-spectrum coverage. Rabies prophylaxis is indicated for bites by carnivorous wild animals, bats, and unvaccinated domestic animals. Review of the patient's tetanus status is mandatory.

Animals↗

PubMed1992

Electrophysiological responses in the rat tail artery during reinnervation following lesions of the sympathetic supply.

1. Responses to perivascular stimuli have been recorded with intracellular microelectrodes from the smooth muscle of isolated segments of the main caudal artery of rats at various times between 7 and 128 days after all four collector nerve trunks had been lesioned near the base of the tail at 21 days of age. 2. In proximal segments (< 40 mm distal to the lesions), excitatory junction potentials (EJPs) and neurogenic alpha-depolarizations (NADs) evoked by stimuli presented via a proximally located suction electrode were similar to those in the same segments of unoperated control animals of the same age. Supramaximal EJPs in these segments decreased in amplitude with age. 3. Stimuli just supramaximal for EJPs in innervated preparations failed to evoke responses in segments farther than 30-40 mm distal to the lesions at any time after the nerves had been cut and 1 cm excised. Higher voltages evoked slow depolarizing potentials (SDPs) which were of longer time course than EJPs. Similar responses occurred in segments over 60 mm distal to the lesions at 20-50 days after the nerves had been frozen, and in all segments sampled over 100 mm distal to nerve lesions. 4. Spontaneous transient depolarizations (STDs) were recorded at all depths of the media in denervated segments. These occurred at frequencies similar to those of spontaneous events (including attenuated spontaneous EJPs) in innervated segments. 5. The earliest signs of reinnervation (24-42 days after freeze lesions) consisted of very small amplitude EJPs of normal time course which facilitated markedly during a short train of stimuli (5-10 Hz); these were followed by NADs which were large relative to the amplitudes of the EJPs. Less commonly, small focal EJPs of brief time course (resembling spontaneous EJPs in superficial cells of innervated arteries) were evoked in very restricted regions of the vessel wall. 6. At later times (57-128 days postoperative), six of eight segments located 40-70 mm distal to freeze lesions showed EJPs of nearly control amplitude, but NADs that were larger than in equivalent segments from control animals. In the remaining two cases, reinnervation at this level was similar to that seen at the earliest postoperative times. High stimulus voltages prolonged the decay of EJPs in both control and reinnervated arteries. 7. Sensitivity to exogenous noradrenaline, assessed in terms of membrane depolarization, was increased in both denervated and reinnervated segments. 8. Catecholamine fluorescence disappeared from the arteries at a distance greater than 30-40 mm distal to the site of the nerve lesions.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic Fibers↗

PubMed1992

Cloning and nucleotide sequence of the gene coding for citrate synthase from a thermotolerant Bacillus sp.

The structural gene coding for citrate synthase from the gram-positive soil isolate Bacillus sp. strain C4 (ATCC 55182) capable of secreting acetic acid at pH 5.0 to 7.0 in the presence of dolime has been cloned from a genomic library by complementation of an Escherichia coli auxotrophic mutant lacking citrate synthase. The nucleotide sequence of the entire 3.1-kb HindIII fragment has been determined, and one major open reading frame was found coding for citrate synthase (ctsA). Citrate synthase from Bacillus sp. strain C4 was found to be a dimer (Mr, 84,500) with a subunit with an Mr of 42,000. The N-terminal sequence was found to be identical with that predicted from the gene sequence. The kinetics were best fit to a bisubstrate enzyme with an ordered mechanism. Bacillus sp. strain C4 citrate synthase was not activated by potassium chloride and was not inhibited by NADH, ATP, ADP, or AMP at levels up to 1 mM. The predicted amino acid sequence was compared with that of the E. coli, Acinetobacter anitratum, Pseudomonas aeruginosa, Rickettsia prowazekii, porcine heart, and Saccharomyces cerevisiae cytoplasmic and mitochondrial enzymes.

Amino Acid Sequence↗

PubMed1991

The release of neuronal 5-HT from the intestine of a teleost fish, Platycephalus bassensis.

The superfused, isolated intestine of a teleost fish which lacks enterochromaffin cells spontaneously released 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA), presumably from enteric neurons. The release of 5-HT, but not 5-HIAA, increased on transmural electrical stimulation. Addition of tetrodotoxin or omission of Ca2+ from the superfusate prevented the increase in 5-HT release on electrical stimulation. Fluoxetine added to the superfusate increased the amount of 5-HT released spontaneously but also prevented the increase in 5-HT release on stimulation. Pretreatment of fish with reserpine markedly reduced tissue levels of 5-HT and 5-HIAA and led to an almost complete loss of the spontaneous release of 5-HT and an elimination of the stimulated release of 5-HT.

Animals↗

PubMed1991

The time course of the development of the sympathetic innervation of the vasculature of the rat tail.

The development of the sympathetic innervation of the tail vasculature in the rat has been examined using catecholamine fluorescence and immunohistochemical techniques to demonstrate tyrosine hydroxylase (TH) and neuropeptide Y (NPY). The tail was found to be largely devoid of noradrenergic terminals at birth. At the earliest ages, axons within nerve trunks and paravascular axon bundles showed high levels of catecholamine fluorescence, but this virtually disappeared as the innervation of the effectors was achieved. The perivascular plexus on the caudal artery was established over the first six postnatal weeks along a rostrocaudal gradient which was retained in the adult, i.e. proximal regions were more densely innervated than distal ones. The innervation of the rest of the vasculature developed relatively late during this period, with the exception of the arteriovenous anastomoses present in the distal half of the tail. These became innervated about 10 days earlier than the adjacent caudal artery at the same levels, and received a much denser innervation in the adult. At all developmental stages, distributions of TH- and NPY-immunoreactive nerve fibres were identical to those seen with catecholamine fluorescence. The sequence of development suggests that the different vascular targets are innervated by subsets of sympathetic neurons having the same neurochemistry but developing independently.

Animals↗

PubMed1990

The effects of mercuric chloride on calmodulin-mediated Ca2+ transport in rat brain.

We have shown previously that mercuric chloride (HgCl2) inhibits in vitro vasopressin release from the isolated rat neurohypophysis with maximum inhibition occurring with 0.5 mM HgCl2. Associated with the inhibition of hormone release is an increase in 45Ca+2 uptake, an increase in cytosolic 45Ca+2, and a reduction of 45Ca+2 accumulation by mitochondria in the intact gland. In the present series of studies, the effect of HgCl2 on calmodulin (CM) function in neural tissue preparations is reported. Mercuric chloride (0.5 mM) reduced 45Ca+2 binding to CM purified from bovine neurohypophyses by 20% and inhibited endogenous CM-stimulated Ca,Mg-ATPase activity from rat brain mitochondria in a dose-dependent fashion. Ca,Mg-ATPase activity was inhibited by 50 and 80% with 0.5 and 5.0 mM HgCl2, respectively. CM-stimulation of Ca,Mg-ATPase activity was inhibited by calmidazolium (CMZ) with maximal inhibition seen with 0.1 mM CMZ. Reversibility of the HgCl2 interaction with CM was demonstrated using CM-stimulated phosphodiesterase (PDEase) activity from rat brain. HgCl2 inhibited both basal and CM-stimulated PDEase activity in a dose-dependent manner with maximum inhibition occurring with 1.0 mM HgCl2. Preexposure of CM to an inhibitory concentration (1.0 mM) of HgCl2 resulted in no loss of stimulatory PDEase enzyme activity. From these results, we conclude that HgCl2 reversibly interferes with 45Ca+2 binding to CM and also inhibits CM-regulated Ca+2 pumping enzyme systems in the neurohypophysis. The inhibition of vasopressin release from the intact gland in the presence of HgCl2 thus, may be associated with a disruption of calcium in the neurohypophysis.

Animals↗

PubMed1990

Spontaneous drinking: is it stimulated by hypertonicity or hypovolemia?

Ten young female pigs were allowed to eat and drink whenever they wanted, and blood samples were taken without disturbance to the pig. Samples were divided into four categories: 1) base line, i.e., taken when not drinking and not eating; 2) preprandial, i.e., taken when starting to drink just before eating; 3) postcibal, i.e., taken when starting to drink after any eating; and 4) nonprandial, i.e., taken when starting to drink but not in association with eating. Osmolality (mosmol/kgH2O), plasma protein (g/dl), and packed cell volume (%) were, respectively, as follows (mean +/- SE): base line 294.9 +/- 1.8, 6.2 +/- 0.1, and 30.0 +/- 1.2; preprandial 295.1 +/- 1.7, 6.1 +/- 0.2, and 29.7 +/- 1.4; postcibal 295.0 +/- 3.3, 6.5 +/- 0.2, and 31.7 +/- 1.3; and nonprandial 295.2 +/- 1.4, 6.3 +/- 0.1, and 30.0 +/- 1.3. None of the parameters associated with drinking were significantly different from base-line parameters, except for the postcibal rise of packed cell volume. Calculated blood volume differences from base line were as follows: preprandial 0.7 +/- 1.2% fall; postcibal 0.2 +/- 1.7% increase; and nonprandial 0.8 +/- 0.9% fall. It is unlikely that either plasma hypertonicity or hypovolemia stimulates drinking under spontaneous conditions.

Animals↗

PubMed1990

Hypertonic and hypovolemic stimulation of thirst in pigs.

Young female pigs weighing from 15 to 45 kg were used. Plasma osmolality was slowly raised by an intravenous infusion of 15% NaCl. The behavioral threshold was when the pigs began to drink water, and the rise of osmolality was the stimulus. In 23 measurements on 8 pigs the rise of osmolality to initiate drinking was 10.4 +/- 1.4 mosmol/kg (mean +/- SE). There was also an estimated 3.8 +/- 1.4% rise of blood volume. Control infusions of 0.9% NaCl for 1 h usually resulted in no drinking, and plasma osmolality fell by 6.7 +/- 2.1 mosmol/kg, while blood volume did not change. Hypovolemia was effected using furosemide (1 mg/kg body wt) to cause excretion of nearly isotonic urine. Blood volume changes were estimated from plasma protein and packed cell volume data. In 28 measurements on 6 pigs, drinking occurred when blood volume had decreased by 6.7 +/- 1.8%. During 2-h control periods, blood volume did not change appreciably. Plasma osmolality decreased during both the furosemide treatment (by 3.5 +/- 0.7 mosmol/kg) and the controls (by 4.1 +/- 0.8 mosmol/kg).

Animals↗