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Biomedical subjects

C Lucas

Publications and source records attributed to C Lucas.

At least 199 records · Page 11Linked to original sources
PubMed1990

[Recurrent postoperative sciatica. Prospective evaluation of magnetic resonance imaging and x-ray computed tomography with iodine injection].

The respective performance of MRI and CT were studied prospectively in 80 cases. Surgery was indicated in 56 patients after MRI examination and 21 patients after CT; the 21 patients were included in the 56. Among these patients, 45 were reoperated and 11 preferred the medical treatment. Surgery confirmed the diagnosis for 44 patients (from the 45), and the only discordance was the presence of ligament calcification, associated to a disc protrusion not seen on MRI. Surgery confirmed also the diagnosis for the 21 cases diagnosed by CT after iodine injection. However, among the 24 cases of fibrosis diagnosed by CT after i.v. injection were found: 19 recurrent disc protrusions, 4 disc protrusions with fibrosis, and 1 disc protrusion at a level above the operated disc.

Adult↗
PubMed1990

The role of endoscopic retrograde pancreatography (ERP) in blunt abdominal trauma.

The diagnosis of pancreatic injury is often difficult because it lies retroperitoneally in a protected area. Delayed diagnosis and treatment of blunt pancreatic trauma can result in significant morbidity and mortality. Endoscopic Retrograde Pancreatography (ERP) is infrequently used in the diagnosis of pancreatic injury. We reviewed our experience with the use of ERP in patients with blunt pancreatic injury. Two stable patients with traumatic pancreatitis underwent ERP shortly after injury. CT scans revealed a transverse fracture of the distal pancrease in one and fluid accumulation in the other around the pancreas extending to the right kidney and left hepatic lobe. The absence of ductal disruption on ERP allowed nonoperative management of the pancreatitis. Resolution was documented by the absence of symptoms on regular oral intake, normal serum amylase levels, and normal follow-up CT scans. A third patient with persistent fistulae three months postinjury underwent preoperative ERP revealing ductal obstruction. This facilitated the planning of a distal pancreatectomy and subsequently the fistulae healed. A fourth patient underwent an exploratory laparotomy on the basis of clinical and CT scan findings that could have been circumvented with preoperative ERP. ERP in selected patients allows nonoperative treatment in the absence of ductal injury or earlier operative treatment of ductal injury. It also aids the treatment of late complications by delineating ductal anatomy.

Adult↗
PubMed1989

Influence of beta 2 agonism and beta 1 and beta 2 antagonism on adverse effects and plasma lipoproteins: results of a multicenter comparison of dilevalol and metoprolol.

Dilevalol combines vasodilation due to selective beta 2 agonism and nonselective beta antagonism. We studied 311 patients randomized to dilevalol and 138 to metoprolol in a multicenter trial. After a 4-week placebo washout, dilevalol was titrated from 200 to 1,600 mg once daily and metoprolol from 100 to 400 mg to a goal supine diastolic blood pressure less than 90 and greater than or equal to 10 mm Hg decrease from baseline. Responders were followed for 1 year. The average age of patients was 51 years; 72% were men and 54% were white. Both drugs reduced blood pressure effectively to a similar level. Fewer patients discontinued dilevalol than did those taking metoprolol (9 vs 16%; p less than 0.03). More metoprolol-treated patients withdrew because of depression (6 vs less than 1%; p = 0.03) and impotence (5 vs less than 1%; p = 0.03). Lipoprotein levels before and after treatment were measured in 99 patients treated for 53.5 weeks with dilevalol (mean dose 438 mg). Dilevalol increased high-density lipoprotein (HDL) cholesterol by 2.5 mg/dl to 47.2 (p = 0.05), reduced low-density lipoprotein (LDL) cholesterol by 2.5 mg/dl, increased HDL/LDL by 0.03, and decreased total cholesterol/HDL cholesterol by 0.18. Triglycerides increased by 21 mg/dl (p = 0.06). In patients with an initial HDL cholesterol less than 35 mg/dl, dilevalol increased it by 9 mg/dl. In patients treated with metoprolol, the only significant change (p = 0.02) was a 41.9-mg/dl increase in triglyceride levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗
PubMed1989

Designing CD4 immunoadhesins for AIDS therapy.

A newly-constructed antibody-like molecule containing the gp120-binding domain of the receptor for human immunodeficiency virus blocks HIV-1 infection of T cells and monocytes. Its long plasma half-life, other antibody-like properties, and potential to block all HIV isolates, make it a good candidate for therapeutic use.

Acquired Immunodeficiency Syndrome↗
PubMed1989

MRI anatomy of the nerves of the upper limb.

In view of the good anatomic definition of the images obtained by magnetic resonance imaging (MRI), we have defined MRI sections allowing study of the nerves of the upper limb.

Arm↗
PubMed1989

Effect of dose and immunization schedule on immune response of baboons to recombinant glycoprotein 120 of HIV-1.

To evaluate the immunogenicity of purified recombinant envelope glycoprotein of HIV-1 (rgp120) as a potential vaccine for AIDS, the antibody response of 45 baboons to rgp120 was investigated using an adjuvant (alum) and route of administration (intramuscular) suitable for humans. The primary purpose was to evaluate the effects of different doses and immunization schedules on the antibody response to rgp120 in primates. A secondary objective was to evaluate possible adverse consequences of rgp120 immunization. A liquid-phase radioimmunoprecipitation (RIP) assay for detection of rgp120-reactive antibodies revealed that rgp120 doses of 30-300 micrograms per administration resulted in nearly indistinguishable serum antibody responses. However, significant enhancement of serum antibody titers was observed when the interval between the second and third administrations was increased from 4 to 20 w. Although changing the interval significantly altered the magnitude of resulting peak titers, the kinetics of antibody formation were not changed. Thus, of the three schedules of immunization tested, none resulted in a sustained humoral immune response. The significance of the RIP assay for evaluating immune responses was confirmed by analysis showing that the percentage of immunized baboons that developed in vitro HIV-1 serum neutralizing responses was greatest in groups that also exhibited high anti-rgp120 RIP titers. Immunization with rgp120 had no significant adverse effect on any clinical or laboratory parameter monitored over the course of the study.

Acquired Immunodeficiency Syndrome↗
PubMed1989

An enzyme-linked immunosorbent assay to study human relaxin in human pregnancy and in pregnant rhesus monkeys.

A sensitive and specific double-antibody enzyme-linked immunoassay, using a synthetic analogue of human relaxin for standard and immunogen, was developed for the measurement of human relaxin (hRLX) in serum and plasma. No cross-reactivity was observed for human insulin, human insulin-like growth factor-I, hGH, human chorionic gonadotropin, hFSH, hLH or human prolactin. The assay was used to monitor RLX concentrations in samples from men, non-pregnant and pregnant women, and in pregnant rhesus monkeys infused with hRLX. RLX was not detected in serum from men nor from non-pregnant women, while a concentration of 600 ng/l was measured in pooled sera from two pregnant women (pregnancies achieved by in-vitro fertilization). Immunoreactive RLX (1.1 micrograms/g) was found in human corpora lutea taken from ectopic pregnancies at 7 weeks. In an experiment with a pregnant rhesus monkey infused with human RLX analogue, less than 1.5% of the maternal concentration was measured in the fetal circulation. Even though preliminary, these data suggest a low level of transfer of human analogue relaxin across the placenta in a rhesus monkey. Further studies of the physiology of RLX in human pregnancy will be facilitated by the availability of this immunoassay.

Amino Acid Sequence↗
PubMed1989

[Study of the clinical pharmacokinetics of fotemustine in various tumor indications].

Fotemustine (S 10036) is a new nitrosourea compound whose antitumoral activity has been demonstrated, particularly in disseminated malignant melanoma. Pharmacokinetic parameters of this drug were investigated during phase II clinical trials and compared according to tumor type. Twenty-six patients entered the study and received an induction treatment (weekly 100 mg/sq.m of fotemustine in 250 ml of 5% glucose in water over a one-hour IV infusion for 3 consecutive weeks) followed by a 4-week rest period. A maintenance therapy (100 mg/sq.m every three weeks) was proposed in stabilized or responsive patients. Plasmatic assay of fotemustine was carried out by HPLC. Seventy-one cycles were analyzed. A short half-life and a large intra and inter-individual variability of all kinetic parameters (especially plasmatic clearance) was found independent of tumour type. The study of patient's clinical behaviour was shown to be related to the clearance value obtained during the first treatment cycle which seems to predict the clinical response in the case of malignant melanoma. This finding needs to be confirmed in a larger number of patients and in other tumor localizations.

Adult↗
PubMed1989

[Modern imaging in radioanatomic study of the shoulder].

The authors describe the most appropriate imaging technique or techniques for assessment of each anatomical structure in the shoulder: the head of the humerus, socket, acromion, joint space, labrum, musculotendinous structures of the supraspinatus, subscapularis and long biceps muscles. The techniques used are the most useful view of standard X-rays, as well as arthropathy, CT scan, arthroscan, ultrasonography and MRI. This is a preliminary study to assessment of shoulder lesions. In the shoulder, radiologists are frequently required to identify the anatomical disorder as exactly as possible without falling into the traps associated with all forms of imaging even the most sophisticated.

Diagnostic Imaging↗
PubMed1988

Enzyme-linked immunosorbent assays (ELISAs) for the determination of contaminants resulting from the immunoaffinity purification of recombinant proteins.

Two immunoassays have been developed for the quantitation of part-per-million levels of contaminants likely to co-purify with monoclonal antibodies produced in tissue culture and purified by protein A affinity chromatography. These contaminants are bovine IgG originating from the fetal bovine serum used in cell culture, and protein A. Mouse IgG was shown not to interfere in the bovine IgG assay, where contamination levels of 0.2-0.7% bovine IgG were measured in the lots of monoclonal antibody tested. The protein A ELISA was developed with monoclonal antibody included in the standard, and in the preparations of monoclonal antibody tested, 64 parts per million (ppm) or less of protein A were demonstrated. An additional immunoassay was developed to quantitate monoclonal antibody contamination of two recombinant proteins, rHBsAg and rgp 120 from HIV, purified by affinity chromatography with such antibodies. Possible interference of monoclonal antibody quantitation by the respective antigens was examined in this ELISA, and contamination levels of less than 56 ppm of antibody were determined in the purified recombinant proteins. The three immunoassays were shown to be specific for the major protein contaminants in either monoclonal antibodies or the recombinant proteins and were necessary in demonstrating their purity.

Animals↗
PubMed1988

Plastid-localised seed acyl-carrier protein of Brassica napus is encoded by a distinct, nuclear multigene family.

Acyl-carrier protein (ACP) is a key component involved in the regulation of fatty acid biosynthesis in plants. cDNA clones encoding ACP from Brassica napus (oil seed rape) embryos have been isolated using oligonucleotide probes derived from heterologous ACPs. Analysis of the DNA sequence data, in conjunction with N-terminal amino acid sequence data, revealed ACP to be synthesized from nuclear DNA as a precursor containing a 51-amino-acid N-terminal extension. Immunocytochemical studies showed ACP to be localised solely within the plastids of B. napus seed tissue and it would therefore appear that the N-terminal extension functions as a transit peptide to direct ACP into these organelles. Analysis of several cDNA clones revealed sequence heterogeneity and thus evidence for an ACP multigene family. From ten cDNA clones, six unique genes, encoding five different mature ACP polypeptides, were identified. Northern blot hybridisation studies provide evidence that the seed and leaf forms of rape ACP are encoded by structurally distinct gene sets.

Acyl Carrier Protein↗
PubMed1988

Villous adenoma of the common bile duct.

A patient with villous adenoma of the common bile duct presented with obstructive jaundice, weight loss, and icterus. Results of preoperative evaluation suggested cancer of the pancreas or common bile duct. Despite normal findings of intraoperative needle biopsies, a duodenopancreatectomy was performed. Three years after operation the patient is without significant problems. We present the surgical challenge of treating this unique entity.

Adenoma↗
PubMed1988

Interconversion and glucose-induced inactivation of glucose transport systems in Candida shehatae.

During starvation (derepression) glucose-grown cells of Candida shehatae IGC 3607 displayed total interconversion of facilitated diffusion of glucose into a glucose-proton symport, dependent on de novo protein synthesis (proteosynthetic interconversion). The reverse process, inactivation of the proton symport induced by glucose or 2-deoxyglucose, was not accompanied by reemergence of the facilitated diffusion function. The inactivation process had a rapid initial and a slow second phase. The rapid inactivation depended on the external sugar concentration and was reversible while the subsequent slow inactivation was irreversible and independent of the external concentration of the signalling sugar. Interaction of the latter with a surface receptor was indicated by the range of sugar concentrations that affected rapid inactivation.

Biological Transport↗
PubMed1988

Human immunodeficiency virus type 1 challenge of chimpanzees immunized with recombinant envelope glycoprotein gp120.

The major envelope glycoprotein, gp120, of human immunodeficiency virus type 1 (HIV-1) was purified from a Chinese hamster ovary cell line transfected with a truncated form of the HIV-1 env gene. The recombinant glycoprotein (rgp120) was formulated with aluminum hydroxide adjuvant and was used to immunize chimpanzees. The recombinant preparation was effective in eliciting cellular and humoral immunity as well as immunologic memory. Anti-rgp 120 antibodies reacted with authentic viral gp120 in immunological blot assays and were able to neutralize HIV-1 infectivity in vitro. Sera from the rgp120-immunized animals were able to neutralize HIV-1 pseudotypes of vesicular stomatitis virus prepared from the IIIB isolate, from which the gene encoding rgp120 was derived, as well as two heterologous isolates, ARV-2 and RF. The immune response elicited against the rgp120 was not effective in preventing viral infection after intravenous challenge with HIV-1. The implications of these results on HIV-1 vaccine development are discussed.

Acquired Immunodeficiency Syndrome↗