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C J Smith

Publications and source records attributed to C J Smith.

At least 19 recordsLinked to original sources
PubMed1992

Molecular cloning and expression of human myocardial cGMP-inhibited cAMP phosphodiesterase.

We have cloned a cDNA for a myocardial cGMP-inhibited cAMP phosphodiesterase (cGI PDE) from a human heart cDNA library in lambda Zap II. The open reading frame [3.5 kilobases (kb)] of cDNA clone n.13.2 (7.7 kb) encodes a protein of 125 kDa. In Northern blots of total human ventricle RNA, a single mRNA species (8.3 kb) hybridized with a 4-kb EcoRI restriction fragment of clone n.13.2 cDNA (containing the entire open reading frame). The carboxyl-terminal region of the deduced amino acid sequence of the cGI PDE contains the putative catalytic domain conserved among mammalian PDE families. A partial cDNA clone, n.2, encoding a truncated, 54-kDa cGI PDE containing the conserved domain was expressed as a catalytically active fusion protein in Escherichia coli. cAMP hydrolytic activity was inhibited by cGMP and OPC 3911 but not by rolipram. Thus, this report provides direct proof that the conserved domain contains the catalytic core of cGI PDEs.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1992

Insulin and isoproterenol induce phosphorylation of the particulate cyclic GMP-inhibited, low Km cyclic AMP phosphodiesterase (cGI PDE) in 3T3-L1 adipocytes.

The cGI PDE in particulate fractions of differentiated adipocytes (but not control 3T3-L1 fibroblasts) was cross-reactive with a polyclonal antibody raised against the bovine adipose cGI PDE. The 3T3-L1 adipocyte cGI PDE is a 135 kDa protein which is phosphorylated in 32P-labeled cells in response to beta-agonist or insulin. These results indicate that the 3T3-L1 cGI PDE is similar in structure and hormonal regulation to the analogous enzyme in the rat adipocyte.

3T3 Cells↗
PubMed1992

Graded work exposure to promote work return after severe hand trauma: a replicated study.

Fifty-one patients with posttraumatic stress disorder after work-related hand injuries were placed on a graded work exposure program to facilitate return to work. These patients consisted of an initial group of 25 patients and a replication group of 26 patients. The program returned 92% of the initial group and 88% of the replicated group to work with their previous employers. At 6-month follow-up, 88% of the initial group and 80.1% of the replication group were still working full-time at the jobs to which they had returned. All of the patients not working with their previous employer at follow-up had appraisal/projected flash-backs, which have previously been associated with a 90% failure to return to work. This intervention was successful with 73% of the patients experiencing such flashbacks. In conclusion, graded work exposure was an effective treatment to promote return to work for patients experiencing significant psychological symptomatology after severe hand injury.

Accidents, Occupational↗
PubMed1992

Activation of a cryptic streptomycin-resistance gene in the Bacteroides erm transposon, Tn4551.

Bacteroides compound transposons encoding erm resistance are highly homologous but previous studies have shown some divergence of Tn4551. Results presented here describe a novel Tn4551 streptomycin-resistance gene, aadS, that was phenotypically silent in wild-type Bacteroides. However, aadS expression could be activated by a trans-acting chromosomal mutation. The aadS-encoded peptide displayed significant homology to Gram-positive streptomycin-dependent adenyltransferases, and enzymatic analysis confirmed the production of this activity. Examination of the nucleotide sequence showed that 200 bp upstream of aadS, the DNA base composition changed abruptly from 31% G+C to 48% G+C. These two regions were demarcated by a DNA sequence with homology to the recombination hot spots reported for Tn21 and the Bacteroides ermFU gene and to sequences at the ends of the chromosomal Bacteroides conjugal element, XBU4422.

Amino Acid Sequence↗
PubMed1992

Analysis of rRNA restriction fragment length polymorphisms from Bacteroides spp. and Bacteroides fragilis isolates associated with diarrhea in humans and animals.

The Escherichia coli rRNA operon rrnB was used as a 32P-labeled hybridization probe in Southern blots of genomic DNAs from representative strains of the saccharolytic, gram-negative, obligate anaerobes of the genus Bacteroides. Control experiments with the B. fragilis type strain ATCC 25285 established that nearly identical rRNA fragment patterns were produced when either the E. coli rrnB gene probe or homologous rRNA isolated from B. fragilis was used as the probe. In addition, it was shown that a specific 16S or 23S rrnB gene probe also could be used to produce fragment patterns suitable for analysis. Thirty-one strains from 8 of the 10 recognized Bacteroides species were then examined. The resulting autoradiographs revealed specific fragment patterns for all but one (B. ovatus) of the species tested. Restriction fragment length polymorphisms were observed for many of the strains tested, but these differences did not hinder species classification. The five B. ovatus strains examined did not form a distinct group, and their rRNA fragment patterns displayed a marked heterogeneity. The same approach was applied to a unique set of enterotoxin-producing B. fragilis strains isolated from animals and humans with diarrhea. The results demonstrated that these strains were in fact B. fragilis and that they produce rRNA fragment patterns closely related to those of the type strain ATCC 25285. This set of strains did not appear to form a separate subgroup or genotype within the B. fragilis species, and there were no distinguishable restriction fragment length polymorphisms that could be used to specifically separate enterotoxin-producing strains from nonenterotoxigenic strains.

Animals↗
PubMed1992

Restraint inhibits luteinizing hormone and testosterone secretion in intact male rhesus macaques: effects of concurrent naloxone administration.

The present study investigates how restraint affects the hypothalamo-hypophysial adreno-cortical axis and the hypothalamo-hypophysial gonadal axis in intact, adult male rhesus macaques. Restraint was chosen because it is not physically painful or harmful to the animal, but rather serves both as a physical and psychological stressor. Blood samples were collected from a remote site at 15-min intervals beginning at 07.00 h from tethered adult male rhesus macaques. Each of 4 animals was subjected to 6 h of chair restraint after a 3-hour control period in the animals' home cage. Samples were collected for an additional 6 h at the end of the restraint period when the animal was returned to its home cage. Brief anesthesia with ketamine (administered through the indwelling catheter) facilitated transfer of the animals to and from the chair. Blood samples were collected from 4 undisturbed males to document LH and testosterone secretion throughout the day. Plasma ACTH and cortisol, measured as indexes of stress, were elevated within 15 min after initiation of restraint and remained elevated for most of the restraint period. Conversely, LH and testosterone began to fall immediately after restraint and remained suppressed for several hours after the animals were removed from restraint and returned to their home cage. Testosterone levels were more consistently inhibited than were LH levels, a reflection of the fact that in some animals, testosterone remained low after the return of pulsatile LH secretion. In studies with naloxone (Nx), the opiate receptor antagonist (5 mg bolus plus 5 mg/h) was given beginning either at the initiation of restraint (n = 2) or 2 h thereafter (n = 2), and continued until the end of the restraint period. With Nx treatment of the restrained animals, both ACTH and cortisol were elevated as in the controls and LH and testosterone secretion were significantly increased within 1-2 h. However, after the Nx treatment was terminated and the animals were returned to their home cages, plasma levels of LH and testosterone were not different from levels in restrained animals and were significantly less than levels in untreated animals. These data show that restraint is a potent stimulus for activation of the HPAC axis and inhibits both LH and testosterone release. The pathway through which restraint inhibits LH release probably includes endogenous opiate suppression of hypothalamic GnRH release since Nx partially blocks the effect of stress.

Adrenocorticotropic Hormone↗
PubMed1979

Reactivity of amniotic fluid alpha-fetoprotein with concanavallin A in diagnosis of neural tube defects.

Alpha-fetoprotein (AFP) concanavallin-A-affinity molecular variant patterns were determined in amniotic fluid samples from 10 pregnancies complicated by anencephaly (6), spina bifida (1), Turner's syndrome (1), osteogenesis imperfecta congenita (1), and fetal death (1) and 20 normal pregnancies between 14.6 and 25.5 weeks of gestation. With the exception of one anencephalic pregnancy, the AFP concentrations in samples from women with a fetal abnormality were more than 5 SD above normal for gestational age. In every case, however, the proportion of total amniotic fluid AFP that was not reactive with concanavallin A was significantly smaller in the presence of a fetal abnormality (mean 2%) than when the fetus was normal (mean 20%). The results suggest that measuring the amount of concanavallin-A-non-reactive amniotic fluid AFP will be a valuable test for diagnosing fetal abnormality, especially when an increase in total amniotic fluid AFP concentration is equivocal or gestational age is uncertain.

Amniotic Fluid↗
PubMed1979

Superior colliculus lesions and environmental experience: nonvisual effects on problem solving and locomotor activity.

Bilateral lesions of the superior colliculus were produced in rats reared in either a restricted or complex environment. Problem solving ability in a Hebb-Williams closed field and activity in an open field were subsequently observed in conditions of either bright or dim illumination. Animals with superior colliculus lesions were deficient in problem solving ability and were hyperactive in the open field. Complex environment exposure during development increased problem solving ability and initial ambulation scores in all groups. Extent of pretectal damage and behavioral measures were significantly related for animals reared in the complex, but not in the restricted environment. There were no interactions with illumination level, suggesting that the deficits resulting from collicular lesions are not dependent upon the availability of visual cues.

Animals↗