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Biomedical subjects

J Boyer

Publications and source records attributed to J Boyer.

At least 55 records · Page 3Linked to original sources
PubMed1998

Pancreatic bile-salt-dependent lipase activity in serum of diabetic patients: is there a relationship with glycation?

1. Pancreatic bile-salt-dependent lipase has been detected in human plasma where it has the capability to modify normal low- and high-density lipoprotein composition and structure and to reduce the atherogenicity of oxidized low-density lipoprotein (Shamir R, Johnson WJ, Morlock-Fitzpatrick K, Zolfaghari R, Li L, Mas E, Lombardo D, Morel DW, Fisher EA. Pancreatic carboxyl ester lipase: a circulating enzyme that modifies normal and oxidized lipoproteins in vitro. J Clin Invest 1996; 97: 1696-704). 2. In the present study, we investigated the effect of glycation and particularly that of human serum albumin on the activity of bile-salt-dependent lipase. In vitro, bile-salt-dependent lipase activity decreased in the presence of human serum albumin; however, this was less pronounced in the presence of glycated human serum albumin. In vivo, bile-salt-dependent lipase specific activity was about 2-fold higher in the sera of diabetic patients than in the sera of normal subjects. 3. A significant increase in the specific activity of bile-salt-dependent lipase related to the serum level of glycation was observed. The increase in bile-salt-dependent lipase specific activity was not related to the glucose concentration in serum suggesting that glycation of bile-salt-dependent lipase could not be involved in the observed effects. Although the stability of serum bile-salt-dependent lipase was important enough to allow a systemic action of the enzyme on lipoproteins, it could not explain the higher activity of the enzyme in diabetic serum. 4. We concluded that bile-salt-dependent lipase could be helpful against the premature development of atherosclerosis in diabetes.

Adult↗
PubMed1998

Influence of sex, age and smoking status on patient comfort during gastroscopy with pharyngeal anesthesia by a new benzocaine-tetracaine preparation.

Thirty-seven patients underwent gastroscopy under pharyngeal anaesthesia with benzocaine-tetracaine (Endospray; Axcan Pharma). Patients recorded their perception of intubation, of the rest of the procedure, of taste and of throat well-being on visual analogue scales. Throat well-being and taste scores were better for men than for women. There was a strong trend for smokers to be more intolerant to intubation than nonsmokers. There was a weak but significant correlation for younger patients to be more intolerant to intubation. This study points to age and smoking status as possible factors influencing the perception of gastroscopy under pharyngeal anesthesia.

Adult↗
PubMed1998

Sex hormones in spondylarthropathies. A study in 57 patients.

Studies of the hormonal status of patients with spondylarthropathies are few in number, despite the predominantly male sex ratio characteristic of these diseases. Most suggested an elevation in androgen levels. We determined the following parameters in 57 men with spondylarthropathies: FSH, LH, prolactin, estradiol, total testosterone, free testosterone, delta-4-androstenedione, 17-OH-progesterone, estradiol over total testosterone ratio and estradiol over free testosterone ratio. Results were compared to those in a group of 100 healthy controls. Mean patient age was 41.9 years, and mean disease duration was one year. None of the patients were under corticosteroid therapy. The mean prolactin level was normal (8.4 +/- 4.5 ng/ml), whereas the mean 17-OH-progesterone level was significantly elevated (2.02 +/- 0.8 ng/ml). The estradiol over testosterone ratios were normal. This hormone profile is consistent with partial deficiency in the enzyme 21-hydroxylase, which is encoded by a gene located on chromosome 6 only 600 kb away from the HLA B locus. We suggest that some class I alleles may be associated with an alteration in 21-hydroxylase responsible for an increase in 17-OH-progesterone levels and for macrophage inhibition resulting in delayed elimination of antigens. This hypothesis is consistent with the possibility raised by others that macrophage inhibition may explain the increased prevalence of infections due to intracellular organisms in patients with spondylarthropathies.

Adolescent↗
PubMed1998

Induction of a TH1 type cellular immune response to the human immunodeficiency type 1 virus by in vivo DNA inoculation.

DNA inoculation is capable of producing antigens intracellularly for ultimate presentation to the cellular and humoral components of the immune system and has potential for vaccine strategies against a number of infectious pathogens including HIV-1. It is well documented that the antigenic diversity of HIV-1 and its high level of nucleotide mutations during reverse transcription can lead to escape from immune surveillance. However, data suggest that a CD8-mediated cytotoxic T lymphocyte response may be less susceptible to escape mutants. We have shown previously that in vivo inoculation of rodents and non-human primates with plasmid expression vectors encoding HIV-1 gene products leads to production of HIV-1 antigens and results in the production of both cellular and humoral immune responses. In addition we have also demonstrated previously that these responses lead to protection in several in vivo models. We further demonstrate here that the cellular response induced is a type TH1 response and specific lysis of HIV-infected targets is CD8-mediated.

AIDS Vaccines↗
PubMed1998

[Diagnosis and prognosis of malignant colonic adenoma: methodologic implications].

The subsequent management of patients with endoscopically removed malignant colorectal polyps depends on the pathologist's diagnosis. According to the correlation with clinical outcome previously published, the histological criteria of potential adverse outcome are: the presence of tumour at or near the resection margins, the invasion of colonic submucosa, the lymphatic invasion and the high grade of malignancy. This article aims at providing guidelines for an adequate examination of the polyp specimen and an unambiguous pathology reporting.

Adenoma↗
PubMed1998

[Evaluation of a new MRI cholangiography sequence with a half-Fourier acquisition technic].

PURPOSE: The aim of this study was to evaluate a new MR cholangiography sequence in which thick slices are obtained with half Fourier acquisition (SSFSE) in biliary obstructive diseases. PATIENTS AND METHODS: Fifty patients with suspected bile duct obstruction were prospectively investigated with MR cholangiography using SSFSE sequence with thick slices. The gold standard was ERCP (n = 40), percutaneous cholangiography (n = 1) or surgical findings (n = 9). According to this gold standard, 17 patients had bile duct lithiasis and 21 had neoplastic obstruction. RESULTS: The sensitivity and specificity of MR cholangiography were 100% and 94% for the diagnosis of lithiasis obstruction and 95% and 97% for neoplastic obstruction. Agreement between the MR cholangiogram and the gold standard was good whatever the site of obstruction (range of kappa values: 0.79-1). CONCLUSION: MR cholangiography with SSFSE sequence is a useful, precise and easy to use technique. Acquisition time for thick slices is short (< 2 sec) limiting cardiorespiratory artefacts and eliminating the need for post-treatment.

Adult↗
PubMed1997

An HIV type 2 DNA vaccine induces cross-reactive immune responses against HIV type 2 and SIV.

We have previously reported on the generation of specific functional immune responses after inoculation of animals with expression vectors encoding HIV-1 genes. This article provides the details of the first application of this new technology to induce immune responses against HIV-2. This virus is molecularly and serologically distinct from HIV-1 and is in fact more closely related to the simian immunodeficiency virus (SIV). Anti-HIV-2 and SIV antibodies were induced in mice of three different haplotypes following a single intramuscular inoculation with an HIV-2/ROD envelope glycoprotein expression vector (pcEnv-2). Boosting of animals with pcEnv-2 induced both anti-HIV-2 neutralizing antibodies and T cell-proliferative responses against HIV-2 and SIVmac proteins. We compared the humoral and cellular immune responses of mice injected with pcEnv-2 and then boosted with either the homologous DNA construct or a recombinant Env protein. Animals boosted with pcEnv-2 generated B and T cell immune responses as strong as those of mice boosted with recombinant gp140 protein in adjuvant. Finally, cellular immune responses were significantly increased with the coadministration of pcEnv-2 and a plasmid expressing interleukin 12. We therefore conclude that DNA plasmid inoculation induces cross-reactive anti-HIV-2 and anti-SIVmac immune responses in mice. This technology should be further investigated as a potential vaccine component for this human pathogen.

AIDS Vaccines↗
PubMed1997

The nucleotide sequence of Saccharomyces cerevisiae chromosome XV.

Chromosome XV was one of the last two chromosomes of Saccharomyces cerevisiae to be discovered. It is the third-largest yeast chromosome after chromosomes XII and IV, and is very similar in size to chromosome VII. It alone represents 9% of the yeast genome (8% if ribosomal DNA is included). When systematic sequencing of chromosome XV was started, 93 genes or markers were identified, and most of them were mapped. However, very little else was known about chromosome XV which, in contrast to shorter chromosomes, had not been the object of comprehensive genetic or molecular analysis. It was therefore decided to start sequencing chromosome XV only in the third phase of the European Yeast Genome Sequencing Programme, after experience was gained on chromosomes III, XI and II. The sequence of chromosome XV has been determined from a set of partly overlapping cosmid clones derived from a unique yeast strain, and physically mapped at 3.3-kilobase resolution before sequencing. As well as numerous new open reading frames (ORFs) and genes encoding tRNA or small RNA molecules, the sequence of 1,091,283 base pairs confirms the high proportion of orphan genes and reveals a number of ancestral and successive duplications with other yeast chromosomes.

Base Sequence↗
PubMed1997

Vascular rupture complicating transluminal angioplasty applied on a failed dialysis vascular access in a patient under chronic steroid therapy.

We report a case of venous rupture complicating percutaneous transluminal angioplasty (PTA) applied on a failed dialysis vascular access (VA) in a patient on chronic steroid therapy. This complication resulted in a rapidly growing hematoma which was successfully controlled by a prolonged reinflation of the balloon catheter at the angioplasty site. The absence of oversizing of the balloon catheter and the low inflation pressure at which the perforation occurred suggest a vessel fragility which was probably induced by a long-standing steroid therapy. In dialysis patients in whom steroid therapy does not represent an infrequent therapeutic modality, this potential risk of vascular rupture should be carefully weighted while treating VA stenoses with the use of PTA.

Angioplasty, Balloon↗
PubMed1997

Bile acid concentrations in human and rat liver tissue and in hepatocyte nuclei.

BACKGROUND & AIMS: Bile acids exert cellular and molecular effects in the liver, but little is known about tissue concentrations. The aim of this study was to characterize bile acid composition in human and rat liver tissue and hepatocyte nuclei and examine the effects of experimental cholestasis and bile acid administration. METHODS: Bile acids were measured by gas chromatography-mass spectrometry. RESULTS: Liver tissue concentrations of sham-operated rats were 130.8 +/- 21.3 nmol/g, representing 2%-4% of the bile acid pool; cholic and delta 22-beta-muricholic acids were the major bile acids identified. Concentrations increased 7-8-fold with bile duct ligation; deoxycholate and hyodeoxycholate disappeared. Lithocholate concentrations were higher in ligated rats (6.4 +/- 0.4 vs. 3.9 +/- 0.5 nmol/g for sham-operated). Total bile acid concentrations in human liver tissue were 61.6 +/- 29.7 nmol/g and comprised mainly chenodeoxycholic and cholic acids. Concentrations were higher during ursodeoxycholate or tauroursodeoxycholate administration (157.2 +/- 45.6 and 161.6 +/- 43.4 nmol/g, respectively), and liver tissue was enriched 30% in ursodeoxycholate at the expense of hydrophobic bile acids. Bile acids were identified in rat hepatic nuclei (50-110 pmol/4 x 10(7) nuclei), accounting for < 0.1% of liver tissue levels. CONCLUSIONS: Human and rat liver tissue bile acid concentrations are low, increase with bile acid administration or bile duct ligation, and account for only a small fraction of the bile acid pool.

Adult↗
PubMed1997

Endoscopic detection of early esophageal cancer in a high-risk population: does Lugol staining improve videoendoscopy?

BACKGROUND: The aim of this study was to prospectively compare the diagnostic accuracy of videoendoscopy, with and without Lugol staining, for the detection of esophageal cancer in alcoholic or smoking patients older than 40 years. METHODS: Daily alcohol and tobacco consumption and overt and latent symptoms were noted. The 158 patients included were examined by videoendoscopy and with Lugol dye. RESULTS: The mean consumption of alcohol and tobacco was 86 +/- 49 gm/day for 26 +/- 11 years, and 30 +/- 18 pack-years, respectively. Twenty-five patients had no symptoms. Before Lugol staining, 12 patients had endoscopically identified cancerous lesions. After Lugol staining, 13 patients had 17 esophageal cancers, 3 of which were high-grade dysplasia. The prevalence of esophageal cancer was 8.2%: 95% CI [4,14]. Dye-free surfaces were significantly larger than the endoscopic patterns observed before Lugol staining (11.6 +/- 9.2 cm2 vs 1.4 +/- 1.7 cm2; p < 0.02). CONCLUSIONS: In an alcoholic smoking population, the prevalence of esophageal cancer detected by endoscopy is high and not related to symptoms described by patients. Lugol staining only moderately improves the diagnostic accuracy of videoendoscopy; its main advantage is the assessment of the mucosal extension of esophageal cancer.

Adult↗
PubMed1997

Interobserver agreement on endoscopic diagnosis of bleeding peptic ulcers.

BACKGROUND: The aim of this prospective study was to evaluate the interobserver agreement of stigmata of recent hemorrhage of bleeding peptic ulcers. METHODS: Sixty-one consecutive adult patients were enrolled in the study and nine (three junior and six senior) endoscopists reviewed standardized video recordings of endoscopic examinations. Interobserver agreement was evaluated using the kappa (kappa) index, intraclass correlation coefficient, and proportion of agreement. Observer bias and poorly trained observers were investigated. RESULTS: Interobserver agreement was very good for oozing (kappa = 0.68), good for clot (kappa = 0.51), poor for spurting (kappa = 0.29) and visible vessels (kappa = 0.33), and excellent for the absence of stigmata (kappa = 0.82). Observer bias sometimes occurred and the number of poorly trained observers was low. The kappa indexes were significantly better in senior than in junior investigators: 0.48 +/- 0.16 versus 0.37 +/- 0.26, respectively, p < 0.05. The agreement between the in vivo evaluation and video tape recordings (intraobserver agreement) was good (kappa = 0.60 +/- 0.19). There was no training phenomenon between the first and the second half of the patient group. CONCLUSIONS: The endoscopic classification of bleeding ulcers might be simplified by limiting grading to a few classes. Special attention should be paid to the training of endoscopists.

Adult↗
PubMed1997

Mucosal immunization with a DNA vaccine induces immune responses against HIV-1 at a mucosal site.

Mucosal immunity is the first defense system in protection against mucosal infection by sexually transmitted diseases and subsequent systemic dissemination of infection. Development of vaccines which can induce protective mucosal immunity would have great promise for preventing sexually transmitted diseases including AIDS. DNA vaccines have recently shown certain advantages over other types of vaccines in safety and elicitation of specific immune responses. We have hypothesized that direct delivery of a DNA plasmid coding the HIV-1 envelope (pcMN160) via mucosal routes will stimulate mucosal immunity against HIV-1. The expression of DNA plasmid inoculated intravaginally was detected in various tissues. Intravaginal inoculation of pcMN160 elicits production of vaginal immunoglobulins which specifically bind to the HIV-1 envelope and neutralize HIV-1 infectivity in vitro. These results indicate the feasibility of inducing mucosal immunity following mucosal inoculation of DNA vaccines. When coupled with systemic inoculation of appropriate DNA constructs, effective mucosal and systemic immunity may be generated.

AIDS Vaccines↗
PubMed1997

What role can endoscopy play in the management of biliary complications after laparoscopic cholecystectomy?

BACKGROUND AND STUDY AIMS: This study was carried out to establish the indications for biliary endoscopy due to biliary complications after laparoscopic cholecystectomy (LC). PATIENTS AND METHODS: One hundred nineteen patients (36 men, 86 women; median age 59, range 16-93) were referred for endoscopic retrograde cholangiopancreatography (ERCP) to five centers between 1990 and 1994, and included in the study. The delay between LC and ERCP was 105 +/- 21 days. RESULTS: Four types of complications were observed. a) Fifty-seven patients had residual stones or clip migration into the common bile duct (CBD); all were successfully treated with endoscopic sphincterotomy (ES). b) Twelve major injuries to the CBD were diagnosed by ERCP; successful surgical repair was carried out in most of these cases. c) Twenty patients had a partial biliary stricture; endoscopic stenting was attempted as a primary procedure in eight patients, with a satisfactory outcome in five (63%). d) Thirty patients had a bile leak; endoscopic therapy (26 patients) led to recovery in 18 (69%). The benefit of endoscopic treatment was less clear in five (19%); ES failed to bring about improvement in three patients (12%). CONCLUSIONS: ERCP is indicated when a biliary complication is suspected after laparoscopic cholecystectomy. Endoscopic sphincterotomy is effective for the treatment of retained stones, clip migration, and bile leakage. Endoscopic stenting may be offered as a primary option in partial CBD strictures.

Adolescent↗
PubMed1997

Diagnostic strategies for extrahepatic cholestasis of indefinite origin: endoscopic ultrasonography or retrograde cholangiography? Results of a prospective study.

BACKGROUND AND STUDY AIMS: Due to its lower morbidity, it has been suggested that endoscopic ultrasonography (EUS) might replace endoscopic retrograde cholangiography (ERC) in the management of extrahepatic cholestasis of unknown origin. The present study aimed to compare the diagnostic accuracy of EUS and ERC in the management of cholestasis of unknown origin, taking into account the patient's general status and the necessity of endoscopic therapy. PATIENTS AND METHODS: Sixty-eight patients with cholestasis of unknown origin were studied prospectively. EUS followed by ERC was carried out on a blinded basis by two endoscopists; diagnostic and therapeutic suggestions were made after either examination. During the ERC procedure and before withdrawing the tube, the endoscopist provided the final conclusions and carried out appropriate endoscopic treatment. RESULTS: A correct diagnosis was obtained with EUS and ERC in 94% and in 92% of cases, respectively (not significant). After EUS, diagnostic ERC was necessary for diagnosis and therapy in 24% and 58% of cases, respectively. After ERC, EUS was requested in 41% of cases. The higher the American Society of Anesthesiologists (ASA) grade, the less it was necessary to perform a complementary investigation. In ASA grade 1 patients, endoscopic therapy was suggested in 38% of cases after EUS and in 33% after ERC (not significant); in ASA grade 3 patients, it was suggested in 93% of cases. CONCLUSIONS: The diagnostic sensitivities of EUS and ERC are similar for extrahepatic cholestasis. ERC is first indicated in poor candidates for surgery, since endoscopic therapy is frequently required. In good candidates for surgery, EUS should be carried out first in order to stage a tumor or identify choledocholithiasis.

Adult↗