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Biomedical subjects

H Cook

Publications and source records attributed to H Cook.

At least 37 records · Page 2Linked to original sources
PubMed1991

Central arteriovenous malformations of the maxillofacial skeleton: case report.

Central arteriovenous malformation of the maxillofacial skeleton, though rare, is a well-documented entity. Past treatments have usually included some form of surgical intervention. Surgical resection as an attempt to cure has been effective but costly, ie, in relationship to patient morbidity and hospital expenditures. A case of vascular malformation is presented in which selective angiography and embolization as a primary treatment were used rather than ablative surgery. The patient tolerated the procedures well, with complete resolution of bleeding.

Adult↗
PubMed1990

Use of a pituitary cell dispersion method and primary culture system for the studies of gonadotropin-releasing hormone action in the goldfish, Carassius auratus. I. Initial morphological, static, and cell column perifusion studies.

Two cell dispersion methods for excised goldfish pituitary glands were tested, and a cultured dispersed cell system based on trypsin enzymatic tissue digestion was developed and characterized. Controlled trypsin/DNase treatment of goldfish pituitary gland yielded dispersed cells of high viability (trypsin blue exclusion test) that responded to gonadotropin (GTH)-releasing hormone (GnRH) challenges with GTH secretion in a time- and dose-dependent manner following overnight culture. Electron microscopy revealed that cell preparations produced by the trypsin dispersion were free of cell debris and nerve terminals. The dispersed pituitary cells also retained distinct morphological and immunological identities. Under static incubation conditions, 2-hr treatments with 0.1 nM to 1 microM [Trp7,Leu8]-GnRH (sGnRH) and [D-Arg6,Pro9-N-ethylamide]-sGnRH (sGnRHa) stimulated GTH release with similar efficacy, but with ED50S of 1.92 +/- 0.48 and 0.19 +/- 0.08 nM, respectively. [His5,Trp7,Tyr8]-GnRH (cGnRH-II) stimulated GTH release in a nonsigmoidal, but dose-dependent manner, and with a higher efficacy than sGnRH. In contrast, sGnRH, sGnRHa, and cGnRH-II were equipotent in inducing growth hormone (GH) secretion in static culture studies and with ED50S of 0.29 +/- 0.13, 0.18 +/- 0.11, and 0.19 +/- 0.17 nM, respectively. When trypsin/DNase-dispersed cells cultured overnight with cytodex beads were tested in a cell column perifusion system, dose-related increase in GTH secretion, as well as GH release, were also observed with 0.5 to 50 nM sGnRH. These results suggest that trypsin-dispersed goldfish pituitary cells can be used effectively to study the actions of GnRH on teleost pituitary either in short-term static incubation or column perifusion studies. Differences in the GTH and GH responses to the two native GnRH forms, sGnRH and cGnRH-II, are also indicated.

Animals↗
PubMed1989

A subpopulation of dorsal unpaired median neurons in the blood-feeding insect Rhodnius prolixus displays serotonin-like immunoreactivity.

We describe, for the first time in insects, the presence of serotonin-like immunoreactive dorsal unpaired median (DUM) neurons. In unfed, untreated Rhodnius prolixus, the cell bodies of these DUM neurons displayed only faint serotonin-like immunofluorescence without any detectable fluorescence in the axons. There was, however, an extensive serotonin-like immunoreactive peripheral complex. We have enhanced the immunostaining of the cell bodies and axons of these DUM neurons by using 5,7-dihydroxytryptamine (5,7-DHT) and nerve transection, and have further defined their morphology with cobalt backfilling and Lucifer yellow injection. Injection of 5,7-DHT resulted in enhanced serotonin-like immunostaining, after 24 hours, of five DUM neurons in the mesothoracic ganglionic mass. Each DUM neuron possessed bifurcating serotonin-like immunoreactive axons projecting to the periphery via one of the five bilaterally paired abdominal nerves. Concomitant with the enhanced immunostaining in the cell body and axons of these DUM neurons was the depletion of a serotonin-like immunoreactive neurohaemal area lying on each of the abdominal nerves and the depletion of serotonin-like immunoreactive processes on the body wall. Enhancement of cell body and axon immunostaining was also observed in preparations in which the abdominal nerves had been transected 24 hours previously. The location and morphology of these DUM neurons were studied in further detail by using cobalt backfilling of the abdominal nerves and intracellular injection of Lucifer yellow followed by immunohistochemistry. The five serotonin-like immunoreactive DUM neurons were found to represent a subpopulation in a group of ten DUM neurons located in the mesothoracic ganglionic mass and associated with the abdominal nerves. Each abdominal nerve received projections from two DUM neurons, only one of which was serotonin-like immunoreactive. Electrophysiological recordings revealed that the serotonin-like immunoreactive DUM neurons of Rhodnius had similar properties to previously described octopaminergic DUM neurons of insects. The five DUM neurons in Rhodnius appear to represent a subpopulation of DUM neurons containing serotonin.

Action Potentials↗
PubMed1989

Management of the oral surgery patient addicted to heroin.

A review of the clinical characteristics of heroin addiction and parameters surrounding outpatient and inpatient care of patients afflicted with heroin dependency is presented. A case report demonstrating the difficulties encountered when one elects to treat the heroin addict is included.

Adult↗
PubMed1988

Dorsal roots are absent from the tail of larval Xenopus.

Dorsal roots are absent from the tails of Xenopus larvae. Sensory afferents instead enter the spinal cord via the ventral roots. After reaching the cord these axons travel diagonally within the lateral fasciculus of the cord to reach the dorsolateral fiber bundle in which they ascend to the hindbrain. Sensory afferents entering together in the same ventral root make this traverse individually rather than as a group, but coalesce again at the ascending tract.

Animals↗
PubMed1988

Isolation and characterization of carp prolactin.

Prolactin (PRL) was extracted with acid-acetone from common carp (Cyprinus carpio) pituitary glands and purified by gel filtration on Sephadex G-75, ion-exchange chromatography on DEAE-cellulose, and reversed-phase high-performance liquid chromatography (HPLC) on TSK-gel TMS 250 with a yield of 0.7 mg/g wet tissue. At each stage of purification, fractions were monitored by HPLC on TSK-gel ODS 120T and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Carp PRL was almost equipotent with ovine PRL in retaining plasma Na concentrations in the hypophysectomized killifish, Fundulus heteroclitus. Immunocytochemistry at both the light and electron microscopic levels revealed that carp PRL antiserum specifically stained cells in the goldfish rostral pars distalis. No cross reaction with putative growth hormone (GH) cells in the proximal pars distalis was observed. The specificity of the carp PRL antiserum was confirmed by immunoblot studies. Although immunostaining of both carp and salmon PRL was observed, there was no cross reaction to GHs from these species. Carp PRL had a sole N-terminal residue of valine, a molecular weight of 23 kDa in SDS-PAGE, and an isoelectric point of 7.3 by gel electrofocusing. Based on these results, together with the knowledge of physicochemical properties of salmon and tilapia PRLs, we propose a standard procedure for isolation of fish PRLs.

Animals↗
PubMed1987

Gonadotropin production and release in female goldfish (Carassius auratus) after administration of pimozide and an LHRH analogue as studied by electron microscopy and radioimmunoassay.

The effect of pimozide and an LHRH-analogue (LHRH-A) on gonadotropic cells of the goldfish pituitary gland were described qualitatively and quantitatively. A scale of four categories was devised to reflect various ultrastructural appearances of the cells. Experimental animals were divided into a control group, a group injected with LHRH-A alone, pimozide alone, and groups receiving these two substances in combination. Fish injected with the single substance were killed 12 h after injection while the groups receiving the combined treatments were killed at 4, 12 and 48 h. Serum levels of gonadotropin measured by radioimmunoassay were used to indicate whether an increase in hormone release had occurred. An immunocytochemical technique, the protein A-gold procedure, assured that the cells studied were gonadotropes. The control group showed variation in the profiles of gonadotropic cells. The single treatment groups showed some increase in secretory inclusions. At 4 h after injection the combined treatment caused a significant increase in hormone granules; at 12 and 48 h there was a gradual decrease in content of secretory products, and an increase in vacuolization. The results indicate that the combined pimozide and LHRH-A treatment stimulated gonadotropin production as well as release.

Animals↗
PubMed1986

Gonadotropic hormone-releasing hormone (GnRH) bioactivity in the brain of the immature rainbow trout, Salmo gairdneri: the effect of testosterone.

The effect of exogenous testosterone on the synthesis and release of a bioactive gonadotropic hormone-releasing hormone (GnRH)-like substance has been studied in juvenile male rainbow trout. Long-term testosterone treatment caused an increased gonadotropic hormone (GTH) release and precocious sexual maturity. Tel- and diencephalon extracts from long-term testosterone-treated juvenile rainbow trout showed significantly higher GTH-releasing activity than extracts from control animals when injected in short-term testosterone-pretreated juvenile rainbow trout. It was concluded that long-term testosterone treatment caused an increased synthesis and release of GnRH-like material.

Animals↗
PubMed1986

Dimensional salience and speeded sorting of orientation by kindergarten and fourth-grade children.

Perceptual sensitivity and cognitive processing hypotheses relating to orientation perception in kindergarten and fourth-grade children were tested. Assessment of dimensional salience for orientation and form revealed that subjects at both grade levels identified geometric figures as being alike on the basis of form regardless of orientation condition. The effects of dimensional salience and orientation condition on speeded sorting were then investigated. Kindergarten results supported the cognitive processing prediction that orientation sorting times would vary as a function of orientation condition, but no differences were obtained for the fourth-grade subjects. In addition, the results indicated a substantial improvement in kindergarten performance when sorting on the basis of form as compared with orientation. Dimensional salience had much less effect on fourth-grade sorting times.

Attention↗
PubMed1985

Age and sex differences in the cooperative and noncooperative behavior of pairs of American children.

Game playing behavior of same and mixed sex pairs of 5-, 8-, and 11-year-old American children was compared, using a game in which cooperative behavior maximized reward. Pairs of 8- and 11-year-old children were relatively more cooperative and attained significantly more Joint Reward Goals than 5-year-old pairs. Older pairs were not maximally cooperative, however, in terms of all the dependent measures; in adjusting for initial differences on practice trials, 5-year-olds and 8-year-olds took less time than the 11-year-olds, and 11-year-old pairs of boys took significantly more time than all other pairs. In addition, cooperative behavior increased across trials, especially for the 11-year-old children.

Child↗
PubMed1983

Effects of monosodium L-glutamate on pituitary innervation in goldfish, Carassius auratus.

Monosodium L-glutamate was injected intraperitoneally into goldfish at a dosage of 2.5 mg/g body wt. The first noticeable effect in the pituitary, 30 min postinjection, was marked swelling of pituicytes in the neurohypophysis (NH). Eighteen hours postinjection a large number of degenerating type B fibers were found in the NH of the proximal pars distalis (PPD), while all type A fibers, and type B fibers in other parts of the pituitary, remained unaffected. Because glutamate causes a lesion in the nucleus lateral tuberis (NLT), from the anterior margin of the pituitary stalk through to the posterior end of the nucleus, and a minor lesion in the nucleus preopticus periventricularis, it is likely that the NLT is the origin of the degenerative type B fibers in the proximal NH. The significance of these results is discussed in relation to the neuroendocrine regulation of the pituitary functions in goldfish.

Animals↗
PubMed1983

Ultrastructural immunocytochemistry of growth hormone cells in the goldfish pituitary gland.

The immunocytological activity of an antiserum to carp growth hormone was studied on the goldfish pituitary gland, using a peroxidase-antiperoxidase ultrastructural technique. The reaction was specific for secretory granules in cells in the proximal pars distalis categorized as growth hormone cells on the basis of ultrastructural characteristics. The results support the specificity of the antiserum for growth hormone and provide firm identification of the growth hormone cells in goldfish.

Animals↗
PubMed1980

Brain lesions and short-term endocrine effects of monosodium L-glutamate in goldfish, Carassius auratus.

Monosodium L-glutamate (MSG) was injected intraperitoneally into goldfish at a dosage of 2.5 mg/g body weight. At 24 h post-injection there was a marked hypertrophy and edema in the region of the nucleus lateralis tuberis (NLT) from the anterior margin of the pituitary stalk through to the posterior end of the NLT, irrespective of the sex of the goldfish. A similar hypertrophy and edema occurred ventral to the anterior commissure in the preoptic region in the anterior-ventral nucleus preopticus periventricularis (NPP). At 6 h post-injection a slight vacuolization was evident in these two regions, and at two days the hypertrophy and edema had abated from the extent observed at 24 h post-injection. At five and eight days post-injection only necrotic cells were found in the affected NLT region, but only a small band of necrotic cells was evident in the anterior-ventral preoptic region. No other brain lesions were evident. Serum levels of gonadotropin (GtH) were increased at 6 h, 24 h, and two days after treatment with MSG, but were similar to control values at five, seven and eight days after MSG in male and female goldfish. Exocytosis of small dark secretory granules in gonadotrophs was evident at 24 h after MSG in a fish with a somewhat greater increase in serum GtH than usually found. The time course of increased serum GtH levels postinjection of MSG is consistent with the observed time course of hypertrophy and atrophy of NLT neurons; the increase in serum levels of GtH is interpreted to reflect a stimulation of release of GtH-releasing factor from neurons in the NLT. Electron microscope investigation indicates that prolactin cells have increased secretory and synthetic activity from 24 h through to seven days post-injection of MSG. The mechanism for stimulation of the prolactin cells by MSG is not known. No other changes in activity of adenohypophysial secretory cells were found.

Animals↗