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Biomedical subjects

C Lucas

Publications and source records attributed to C Lucas.

At least 217 records · Page 12Linked to original sources
PubMed1987

Molecular cloning and sequence analysis of complementary DNA encoding rat mammary gland medium-chain S-acyl fatty acid synthetase thio ester hydrolase.

Poly(A)+ RNA from pregnant rat mammary glands was size-fractionated by sucrose gradient centrifugation, and fractions enriched in medium-chain S-acyl fatty acid synthetase thio ester hydrolase (MCH) were identified by in vitro translation and immunoprecipitation. A cDNA library was constructed, in pBR322, from enriched poly(A)+ RNA and screened with two oligonucleotide probes deduced from rat MCH amino acid sequence data. Cross-hybridizing clones were isolated and found to contain cDNA inserts ranging from approximately 1100 to 1550 base pairs (bp). A 1550-bp cDNA insert, from clone 43H09, was confirmed to encode MCH by hybrid-select translation/immunoprecipitation studies and by comparison of the amino acid sequence deduced from the DNA sequence of the clone to the amino acid sequence of the MCH peptides. Northern blot analysis revealed the size of the MCH mRNA to be 1500 nucleotides, and it is therefore concluded that the 1550-bp insert (including G X C tails) of clone 43H09 represents a full- or near-full-length copy of the MCH gene. The rat MCH sequence is the first reported sequence of a thioesterase from a mammalian source, but comparison of the deduced amino acid sequences of MCH and the recently published mallard duck medium-chain S-acyl fatty acid synthetase thioesterase reveals significant homology. In particular, a seven amino acid sequence containing the proposed active serine of the duck thioesterase is found to be perfectly conserved in rat MCH.

Amino Acid Sequence↗
PubMed1987

Effect of dexamethasone on cytochrome P-450 mediated metabolism of 2-acetylaminofluorene in cultured rat hepatocytes.

The metabolism of 2-acetylaminofluorene (AAF) to its six oxidative metabolites has been used to investigate the effect of dexamethasone on cytochrome P-450 activity in cultured rat hepatocytes. In control hepatocytes the metabolism of AAF to its 1-, 5-, 7-, 9- and N-hydroxylated metabolites rapidly declined in culture over the first 24 hr while 3-hydroxylation remained relatively constant. These activities either remained unchanged or increased slightly during the next 48 hr in culture. The addition of dexamethasone (100 nM) to the culture medium had little effect in arresting the initial decline but by 72 hr the 7-, 5- and 3-hydroxylations increased to values 2.5, 16 and 21 times the respective 24-hr values. The inductive effect of dexamethasone on the 3- and 5-hydroxylations of AAF was maximal at 100 nM whereas the 7-hydroxylation increased linearly as a function of the dexamethasone concentration up to 1 microM. Cortisol and corticosterone and the non-glucocorticoids fluoxymesterone and methyltestosterone induced a pattern of AAF metabolism resembling that in dexamethasone-treated cultures, suggesting that a range of steroids not restricted to glucocorticoids may induce multiple cytochrome P-450 isozymes via related mechanisms. Pregnenolone 16 alpha-carbonitrile induced only the 7-hydroxylation of AAF probably reflecting induction of cytochrome P-450p. While dexamethasone was a strong inducer of the 3- and 5-hydroxylations of AAF in hepatocyte culture, assay of these activities in freshly isolated cells after in vivo treatment with dexamethasone showed a strong induction of 7-hydroxylation but only small effects on 3- and 5-hydroxylations. Indeed the profile of AAF metabolism induced in culture by dexamethasone resembles more closely the profile induced by 3-methylcholanthrene in vivo. These data suggest that factors yet to be identified strongly influence the steroid-induced pattern of cytochrome P-450 gene expression.

2-Acetylaminofluorene↗
PubMed1987

A quantitative immunofluorescence test for detection of serum antibody to Sendai virus in mice.

A simple, semi-automated immunofluorescence assay, (TRACK XI), was developed for the detection and quantitation of circulating antibodies to Sendai virus in mice. The assay was validated by selecting Sendai virus-free and naturally infected mice from six different colonies and testing each serum in both ELISA and quantitative immunofluorescence (QIF) assays. The QIF test utilizes Sendai viral proteins immobilized within a dried colloid gel and permits serum antibody quantitation in 30 minutes. Using a dedicated fluorometer, antibody titers in test sera are calculated automatically from a three-point best fit calibration line. The QIF test gave 92.9% agreement with the ELISA and proved to be a reproducible, accurate and convenient assay for the quantitative measurement of serum antibody to Sendai virus in mice.

Animals↗
PubMed1985

The temperature profiles of growth, thermal death and ethanol tolerance of the xylose-fermenting yeast Candida shehatae.

The temperature profile of growth and thermal death of the xylose-fermenting yeast Candida shehatae was dissociative. The ARRHENIUS plot of growth lacked a descending supraoptimal branch and the specific growth rate at the maximum temperature for growth (around 31 degrees C) was not significantly different from its values at the other temperatures studied (down to 20 degrees C). Ethanol enhanced thermal death by increasing its entropy of activation (entropy coefficient 16.1 entropy units mol-1]-1). The temperature profile of ethanol tolerance with respect to growth displayed a temperature plateau (10-17.5 degrees C) of maximum ethanol tolerance (limit 6% v/v of ethanol) while the toxic effects of ethanol increased on either side of the plateau depressing the maximum temperature for growth from 31 to 17.5 degrees C and increasing the minimum temperature for growth from 2.5 to 10 degrees C.

Candida↗
PubMed1985

[Prolactin adenoma in a 14-year-old boy].

Prolactin dosage in delayed growth and puberty leads to the diagnosis of pituitary prolactinoma in a 14 years old boy. Adenoma's size, visual disturbance leads us to elect surgical treatment but persistent hyperprolactinemia after surgery requires medical treatment with bromocriptine.

Adenoma↗
PubMed1983

Multicenter clinical evaluation of long-term efficacy and safety of labetalol in treatment of hypertension.

The long-term efficacy and safety of labetalol, an antihypertensive agent with combined beta- and alpha-blocking activity, were evaluated alone (number = 193) and in combination with a diuretic (number = 144) in an open-label multicenter trial of 337 hypertensive patients aged 21 to 75 years, including initially 205 (61 percent) men and 219 (65 percent) Caucasians. There were 219 (65 percent) mild, 85 (25 percent) moderate, and 33 (10 percent) severe hypertensive patients. Labetalol (100 to 1,200 mg twice a day) alone or in combination with a diuretic reduced the mean standing blood pressure by 13/11 and 25/16 mm Hg to 135/88 and 130/91 mm Hg, respectively (p less than 0.01), and supine blood pressure by 6/7 and 18/13 mm Hg to 141/86 and 138/90 mm Hg (p less than 0.01), respectively. Blood pressure reductions observed at one month were maintained after one year; 206 (62 percent) patients had 10 mm Hg or greater reductions and 184 (56 percent) patients were maintained at diastolic blood pressures less than 90 mm Hg. Most frequently reported drug-related side effects included fatigue (14 percent), dizziness (12 percent), nausea (11 percent), nasal stuffiness (8 percent), headache (4 percent), and male sexual dysfunction (14 percent). Side effects were generally of mild to moderate intensity and often transient. In addition, in 27 (8 percent) patients reversible asymptomatic transaminase elevations to greater than twice normal developed at some time during the study. In 13 (4 percent) patients these alterations resolved during continued labetalol therapy, but in five (2 percent) patients these marked elevations led to discontinuation of the drug. A total of 32 (9.5 percent) patients were terminated prematurely due to side effects (most commonly genitourinary or gastrointestinal) possibly attributable to the drug. These findings indicate that labetalol with or without a diuretic is a potentially effective, safe, and relatively well-tolerated long-term antihypertensive therapy.

Adult↗
PubMed1983

[Basic therapy of rheumatoid arthritis with thiopronine. Preliminary results].

A long term open study of the use of thiopronine in the treatment of 38 patients with ARA classified "classic" or "definite" rheumatoid arthritis is reported. Doses of the drug were increased from an initial 250 mg per diem by the addition of 250 mg every 15 days to 1 g per diem. After 6 months testing, results were satisfactory (good and fair) in 65% of the cases in both biological and clinical terms. In 15% of the cases, treatment was interrupted mainly due to mucous and cutaneous side effects. These preliminary results confirm reports in the literature and encourage further experiment.

Administration, Oral↗
PubMed1982

[Triamterene induced nephrolithiasis (author's transl)].

Various studies have demonstrated a relationship between nephrolithiasis and the ingestion of certain drugs. We are particularly interested in the effects of triamterene. Five published case studies on patients of both sexes between 43 and 60 years of age have proven that a regular consumption of normal doses of triamterene has a direct effect upon the formation of renal stones. The stones analysed by infra-red spectrophotometry during the above observations contained from 20 to 100% of triamterene and it's metabolite hydroxytriamterene, following a daily consumption of 150 to 350 mg during a period of 6 to 38 months. It has been confirmed that triamterene and it's metabolite hydroxytriamterene are very poorly soluble and super-saturate the urine for a brief period following the ingestion of the drug. Triamterene might also intervene in the initial phenomena of nucleation. It is therefore recommended that triamterene be used with caution in those patients presenting a history of nephrolithiasis. The existence of drug induced nephrolithiasis reinforces the importance of the technique of renal stone analysis, and the necessity of a systematic study of all renal stones found. This will allow us to develop the study of the correlations between the different episodes of renal stone disease, the nature of the treatment undertaken and the systematic analysis, layer by layer, of the stone.

Adult↗
PubMed1982

[Medulloblastoma].

Explore the source record for details and available documents.

Cerebellar Neoplasms↗
PubMed1982

[Pre- and postoperative endocrine function in children with craniopharyngioma ].

17 children presenting with craniopharyngioma were studied from 1970 to 1980. Presenting symptoms were usually reflecting endocrine dysfunction (13 of 17 cases), such as growth retardation, weight abnormalities, diabetes insipidus and hypothyroidism. Unfortunately, these signs were most often misinterpreted (10 of 13 cases) so that when diagnosis was made dissociated hypopituitarism was present. Further impairment of endocrine function always followed surgical excision. In most children pituitary insufficiency becomes complete and permanent. These results are similar whatever the tumor site and surgical procedure. Growth goes on and puberty occurs without treatment in a few cases but in the majority of them substitutive therapy is necessary.

Adolescent↗
PubMed1981

Response of graft versus host disease to high doses of methyl prednisolone.

High dose methyl prednisolone (HDMP) was used to treat 25 episodes of graft versus host disease (GVHD) in 13 patients after bone marrow transplantation for aplastic anaemia or acute leukemia. All patients showed rapid improvement of GVHD following HDMP with resolutions of gut and skin manifestations over several days, but liver GVHD was less responsive to treatment. The major complication of treatment was infection and four patients died from infection following HDMP. The mode of action of HDMP may be a nonspecific anti-inflammatory effect but it appears to be rapidly effective in controlling GVH reactions.

Adolescent↗
PubMed1980

Hydrostatic mechanism in the roll-over test.

The roll-over test has been reported to predict pregnancy-induced hypertension. The arm used to record blood pressure has never been specified. Since the level of the arm with reference to the heart is of great importance in the interpretation of blood pressure, we recorded the roll-over response (blood pressure change from left lateral to supine position) first in the right and then in the left arm of 9 men and 8 nonpregnant women. In addition, blood pressure was measured simultaneously in both arms in 10 pregnant primigravidas. In the men and nonpregnant women the mean diastolic blood pressure after rolling over rose when the right arm was used and fell when the left arm was used. The difference in the roll-over response (right versus left arm) was accounted for by the hydrostatic effect produced by the vertical distance between the corresponding brachial arteries with the subject in the left lateral recumbent position. In the pregnant subjects as well, there was a difference between the roll-over response in the right versus left arm, accounted for by hydrostatic factors. However, the increase in blood pressure was greater for both arms, suggesting a real change in central blood pressure.

Adult↗