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Biomedical subjects

J Clements

Publications and source records attributed to J Clements.

At least 91 records · Page 5Linked to original sources
PubMed1986

Sequence analysis and transformation by the catabolic 3-dehydroquinase (QUTE) gene from Aspergillus nidulans.

The induction of catabolic 3-dehydroquinase by quinic acid in Aspergillus nidulans has been shown to involve transcriptional control and yields a single major 0.8 kb mRNA. The nucleotide sequence of the catabolic 3-dehydroquinase QUTE gene has been determined and contains a single uninterrupted open reading frame of 462 bases encoding a 16,505 Da protein of 153 residues. Comparison with the corresponding QA2 gene of Neurospora crassa reveals the absence of 75 nucleotides encoding 25 amino acids from the centre of the QUTE gene of A. nidulans and the presence of 21 additional nucleotides at its 3' end. There is no nucleotide or amino acid homology between these two elements. A 16 bp inverted repeat (5' GGCAGAGCGTTCTGCC) shows similarity to such repeats found in other fungal promoters. The functional integrity of the QUTE gene was demonstrated by the transformation of a qutE mutant strain which regains growth on quinic acid as sole carbon source. Four of the twelve transformed strains examined contained vector sequences integrated at the qutE locus, and these strains all exhibited normal regulation of 3-dehydroquinase even when 16 copies of the QUTE gene were present.

Amino Acid Sequence↗
PubMed1986

Sleep problems in handicapped children: a preliminary study.

Data are reported from an exploratory study looking at the prevalence of sleep problems (broken sleep and limited hours of sleep) in a population of handicapped children. Some degree of difficulty occurred in over a third of the population. There were strong associations with age, a range of serious daytime behavioural difficulties and indices of family stress. Some support for distinct subgroups (night waking, limited hours) was obtained. The implications of these findings are discussed.

Adolescent↗
PubMed1985

Structure of canine pulmonary surfactant apoprotein: cDNA and complete amino acid sequence.

The apoproteins of pulmonary surfactant (PSAP) are thought to be critical for normal surfactant function. They bind to surfactant phospholipids and enhance their ability to form surface films in vitro. These acidic glycoproteins have monomeric molecular weights of 36,000, 32,000, and 28,000 (PSAP-36, -32, and -28). Each member of this family of proteins has a similar amino acid composition and their differences in electrophoretic mobility are due in part to glycosylation. We have derived the full amino acid sequence of PSAP-32 from the nucleotide sequence of PSAP cDNA. A cDNA library was prepared from canine lung poly(A)+ RNA and screened with oligonucleotide probes that were based on the NH2-terminal amino acids of PSAP-32 determined by Edman degradation. This protein has the striking feature of collagen-like and non-collagen-like sequences in the same polypeptide chain. There are 24 Gly-Xaa-Yaa triplets, where Yaa is often hydroxyproline. These repeats comprise one-third of PSAP near the NH2 terminus. The remaining two-thirds of PSAP is resistant to bacterial collagenase digestion and contains a possible N-glycosylation site near the carboxyl terminus. The NH2-terminal one-third of PSAP-32 probably contains the cysteine involved in interchain disulfide bonds.

Amino Acid Sequence↗
PubMed1985

Psychologic factors in low-back-pain disability.

UNLABELLED: Biomechanical tests, physical examination, spinal radiographs, a modified Minnesota Multiphasic Personality Inventory (MMPI), and a psychologic health inventory derived from the Hopkins Symptom Checklist were applied in 321 randomly selected men, ages 18-55. Each subject was evaluated for prior and current low-back pain (LBP) complaints by use of a modification of the McGill pain questionnaire. Subjects were then categorized as having no LBP (n = 106, 33%), moderate LBP (n = 144, 44.8%), and severe LBP (n = 71, 22.1%). Subjects were further subcategorized as not disabled (defined as equal or less than seven days of work lost in the previous year) and disabled (work loss greater than seven days in the prior year). RESULTS: cumulative scores of the Hopkins Checklist showed that a mean score for no LBP equaled 2.5 +/- 2.9; moderate LBP was 4.3 +/- 3.2; and severe LBP was 4.6 +/- 3 (p = .0000). The disabled group was significantly different on both MMPI and Hopkins Checklist. The 20 disabled subjects had significant elevations of hypochondriasis (p = .0006) and hysteria (p = .005) when compared with nondisabled subjects with LBP. The mean score for disabled subjects on the Hopkins Checklist was 7.35 +/- 4.49, while the score was 4.17 +/- 3.15 (p = .0001) for the nondisabled subjects with LBP. In the general male population, patients with disabling LBP conditions form a distinctive subgroup comparable to those patients seen in selected LBP clinics.

Adult↗
PubMed1984

Lack of neutralizing antibodies to caprine arthritis-encephalitis lentivirus in persistently infected goats can be overcome by immunization with inactivated Mycobacterium tuberculosis.

The pathogenesis of the persistent progressive diseases of sheep (visna-maedi) and goats (arthritis-encephalitis) is dependent on continuous replication of the causative lentiviruses. One subgroup of these viruses, Icelandic visna virus, accomplishes this form of replication by undergoing antigenic mutation. Mutant viruses arising late in the infection escape neutralization by antibodies directed to the parental virus. In contrast, we show here that viruses obtained from persistently infected sheep and goats with natural disease in this country do not induce virus-neutralizing antibodies, although antibodies to virus core proteins were produced. The lack of neutralizing antibodies was not overcome by hyperimmunization of animals with concentrated preparations of live or inactivated virus. Thus, failure to produce these specific antibodies was not due to lack of sufficient antigen or interference with the immune response because of the ability of these viruses to infect macrophages. The hyporesponsive state, however, was overcome by immunization of animals with virus and large amounts of inactivated Mycobacterium tuberculosis. Induction of agglutinating and neutralizing antibodies by this method was probably due to a unique form of antigen processing by macrophages activated by M. tuberculosis. Neutralizing antibodies were produced for the first time against the caprine arthritis-encephalitis virus by this method. These antibodies have similar biological properties to those induced by Icelandic visna virus. They belong to the immunoglobulin G1 subclass, they are effective against a narrow range of caprine arthritis-encephalitis viruses, and they identify (for the first time) antigenic variants among these caprine agents.

Animal Diseases↗
PubMed1984

Spine radiographs in patients with low-back pain. An epidemiological study in men.

A cohort of 321 men between the ages of eighteen and fifty-five was randomly selected from a group of 1221 men who had been surveyed by a questionnaire. They then had radiographs made of the lumbar spine. Of the 292 subjects fulfilling the criteria for inclusion in the study, ninety-six (32.9 per cent) had never had low-back pain, 134 (45.9 per cent) had had or were having moderate low-back pain, and sixty-two (21.2 per cent) had had or were having severe low-back pain. In the three groups there was a similar frequency of transitional vertebrae, Schmorl's nodes, the disc vacuum sign, narrowing of the disc space between the third and fourth lumbar and the fifth lumbar and first sacral vertebrae, and claw spurs. When there were traction spurs or disc-space narrowing, or both, between the fourth and fifth lumbar vertebrae, an increased incidence of severe low-back pain was evident. There also was a significant association of these two radiographic findings with symptoms (pain, weakness, and numbness) in the lower limbs. The measured lumbar lordosis, the length of the transverse process of the fourth lumbar vertebra, and the relationship between the fourth and fifth lumbar vertebral bodies with reference to the intercristal line had no association with the low-back pain. Increased lumbar lordosis had a significant association with decreased disc-space height and wedging deformity of the disc between the fourth and fifth lumbar vertebrae.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Positive control and autogenous regulation of the nifLA promoter in Klebsiella pneumoniae.

The nitrogen fixation (nif) genes of Klebsiella pneumoniae are specifically regulated by the products of the nifLA operon. We have located the promoter of this operon, and identified sequences required for nifLA transcription. Transcription from this promoter is shown to be positively regulated by the ntrC gene product (which coordinates the expression of many operons required for nitrogen assimilation) and also autogenously by the product of the nifA gene.

Base Sequence↗
PubMed1983

Insulin hypoglycaemia and cholinergic blockade: response of plasma immunoreactive beta-endorphin.

Six normal subjects were studied to investigate the mechanisms involved in the release of immunoreactive beta-endorphin (ir-beta EP) in response to insulin hypoglycaemia. Insulin alone (0.2 U/kg body weight) was followed after a 30 min lag period by a congruent to 2.5 fold elevation of plasma ir-beta EP, with a return to basal levels by 90 min. Concurrent infusion of 10% dextrose at 250 ml/h for 2 h prevented the increase in plasma ir-beta EP levels, suggesting an effect of hypoglycaemia rather than a direct effect of insulin. Premedication with atropine 0.6 mg at -30 min was followed by hypoglycaemia equivalent to that seen with insulin alone, but no increase in plasma ir-beta EP, suggesting the involvement of cholinergic mechanisms in the neural mediation of ir-beta EP release in response to hypoglycaemia.

Adult↗
PubMed1983

Expression of the prolactin gene in human decidua-chorion.

Messenger RNA (mRNA) purified from human decidua-chorion hybridizes with a 32P-cDNA probe for human prolactin. In contrast, mRNA from human trophoblast and amnion does not hybridize to prolactin cDNA. The migration position on agarose gels of prolactin-specific mRNA from human decidua-chorion is similar to that for mRNA from ovine pituitary, suggesting a similar sized mRNA coding for prolactin in these different tissues and species. These data demonstrate unambiguously that the prolactin gene is expressed in human decidua-chorion, confirming previous immunochemical reports of prolactin production by this tissue in culture.

Amnion↗
PubMed1982

Effect of disodium cromoglycate and cyclic AMP-active drugs on cytotoxic histamine release from rat mast cells.

Disodium cromoglycate and compounds which elevated levels of cyclic AMP in the mast cell variously inhibited cytotoxic histamine release induced by the surface active agents melittin, Tween 20 and Triton X-100. These results are inconsistent with the postulated effects of the drugs on receptor mediated calcium channels and alternative explanations of their action are considered.

Animals↗
PubMed1982

Foot shock analgesia. Lack of correlation with pituitary and plasma immunoreactive-beta-endorphin.

Effects of inescapable foot shock on pain threshold and on levels of immunoreactive beta-endorphin (ir-beta EP) in anterior pituitary, neuro-intermediate lobe and plasma were determined by hot plate test and radioimmunoassay respectively. Whereas handling and conditioned stress failed to alter baseline pain threshold, 20 min inescapable foot shock produced modest and transient analgesia. Levels of plasma ir-beta EP and corticosterone were significantly and concurrently raised by all treatments and remained elevated 40 min after foot shock. Changes in plasma levels of ir-beta EP and corticosterone were found to parallel one another but did not correlate with changes in pain threshold. AP content of ir-beta EP was significantly reduced 60 min after the cessation of inescapable foot shock, and N-IL content from 20 min after. The findings suggest that (i) plasma levels of ir-beta EP and corticosterone do not reflect changes in pain threshold, and (ii) ir-beta EP levels in anterior pituitary, neurointermediate lobe and plasma probably are not causally related to foot shock analgesia.

Analgesia↗