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Biomedical subjects

A Aubert

Publications and source records attributed to A Aubert.

At least 19 recordsLinked to original sources
PubMed1992

[Colorectal villous tumors. Treatment by electro-resection and laser photocoagulation. 134 cases].

Endoscopic snare resection prior to Nd:YAG laser photocoagulation was used to treat benign colorectal villous adenoma. One hundred and thirty four patients were included in the study: 72 with surgical contraindications, 61 for whom surgical resection appeared to be too drastic and 1 who refused surgery. Treatment sessions were repeated every fifteen days until total tumour destruction was achieved. A carcinoma was detected in biopsy specimens obtained during endoscopic treatment of seven patients. Eight patients were lost to follow up. Treatment results could be analysed in 119 patients. A successful treatment was achieved in 108 patients. Tumour destruction was complete in 85.4 percent of the cases with lesions of at least 4 cm in diameter and in 94.3 percent of the cases with smaller lesions. During the average 101 weeks follow up period, 15.7 percent of the patients with total tumour destruction had recurrence. The risk of recurrence was correlated with the number of initial treatment sessions and previous surgical treatment. It would appear that endoscopic resection prior to Nd:YAG laser photocoagulation is a safe and effective method for the destruction of colorectal villous adenomas.

Aged↗
PubMed1992

Phlegmonous gastritis associated with HIV-1 seroconversion. Endoscopic and microscopic evolution.

A 40-year-old man presented with peritonitis. Diagnosis of phlegmonous gastritis was made by laparotomy. Conservative treatment combined with antibiotics was successful. Multiple endoscopies with biopsies illustrate the natural history of this disease. The patient developed HIV-1 seroconversion during hospital stay. Prompt diagnosis and treatment may improve the prognosis of this often lethal disease.

Abscess↗
PubMed1992

Immunization-induced decrease of the CD4+:CD8+ ratio in cats experimentally infected with feline immunodeficiency virus.

In a previous experiment a group of 15 specified pathogen free (SPF) cats were experimentally infected with a Swiss isolate of feline immunodeficiency virus (FIV). A group of 15 SPF cats served as FIV negative controls. Nine cats of each group were vaccinated with a recombinant feline leukemia virus (FeLV) vaccine, six cats in each group with a placebo vaccine. All vaccinated cats developed high antibody titers to FeLV and were protected against subsequent FeLV challenge infection. In both control groups five of six cats became persistently infected with FeLV. Unexpectedly, the primary immune response to the vaccine antigen was significantly higher in the FIV positive group than in the FIV negative. The secondary response was stronger in the FIV negative cats. The goal of the present investigation was to further study the immune response in these 30 cats. They were immunized twice with the synthetic peptide L-tyrosine-L-glutamic acid-poly(DL-alanine)-poly(L-lysine) (TGAL) 21 days apart. Blood samples were collected on four occasions during the immunization process. They were tested for antibodies to TGAL, complete blood cell counts and CD4+, CD8+ and pan-T-lymphocyte counts. The following observations were made: (1) in contrast to the FeLV vaccine experiment, the primary immune response to TGAL was not significantly stronger in the FIV positive cats when tested by enzyme-linked immunosorbent assay (2). The absolute size of the CD4+ lymphocyte population was distinctly smaller in the FIV positive than in the FIV negative cats. The lowest CD4+ values were found in the dually FIV/FeLV infected cats. (3) A population of CD8+ lymphocytes was identified that was characterized by a distinctly weaker fluorescence. The size of this population increased in FIV positive and decreased in FIV negative cats during the TGAL immunization experiment. (4) The CD4+:CD8+ ratio increased in FIV negative cats during TGAL immunization from 1.9 to 2.3. In contrast, in FIV positive animals the CD4+:CD8+ ratio decreased significantly from 1.9 to 1.3 during the same period. From these and earlier data it was concluded that in short-term FIV infection the immune response to T-cell dependent antigens may be increased over that of the controls. Immune suppression develops gradually with duration of the infection. The significant drop of the CD4+:CD8+ ratio over a 5 week immunization period suggests that antigenic stimulation may accelerate the development of immune suppression in FIV positive cats. If this is a general feature, FIV infection may provide a particularly interesting model for studying the pathogenesis of AIDS.

Amino Acid Sequence↗
PubMed1992

Cirrhosis as an independent risk factor for colonic adenomas.

This study aimed to determine the relation between cirrhosis and colorectal adenomatous polyps after adjustment for alcoholism and other confounding variables. Four groups of patients aged 40 years or above were studied. Group I included 100 consecutive outpatients with irritable bowel syndrome, group II 100 consecutive alcoholic inpatients without cirrhosis, group III 100 consecutive inpatients with alcoholic cirrhosis, and group IV included 36 consecutive inpatients with non-alcoholic cirrhosis. All patients underwent colonoscopy. The prevalence of adenomatous polyps was 13% in group I, 26% in group II, 58% in group III, and 22% in group IV (p less than 0.001). The prevalence of adenomatous polyps was greater in patients with cirrhosis than in those patients without (48.5% v 19.5%). This difference remained significant after successive adjustment for alcoholism, sex, age, smoking, and serum cholesterol. The prevalence of adenomatous polyps was greater in alcoholic patients than in non-alcoholic patients (42% v 15.4%) (p less than 0.001). This difference remained significant after successive adjustment for cirrhosis, sex, age, smoking, and serum cholesterol. These results suggest that cirrhosis is an independent risk factor for colorectal adenomatous polyps and confirm that alcoholism increases this risk.

Adult↗
PubMed1992

Abolishment of chronic volume overload. Implications for diastolic function of the systemic ventricle immediately after Fontan repair.

BACKGROUND: In patients with a univentricular heart, the chronic ventricular volume overload is acutely abolished by the creation of a Fontan circuit. This results in an immediate reduction of the ventricular cavity size but also in an inappropriate degree of ventricular wall thickness, at least in the early postoperative period. The implications for the diastolic properties of the ventricle are poorly understood. METHODS AND RESULTS: A chronic volume overload through a modified Blalock-Taussig shunt was created in 10 mongrel dogs. Six weeks later, the shunt was occluded percutaneously with a detachable balloon. The left ventricular end-diastolic dimension and posterior wall thickness were measured with transcutaneous echocardiography. Digitized high-fidelity pressure tracings were used to determine the time constant of isovolumic pressure decay, tau. The isovolumic relaxation time (A2-MVO) and time to minimal left ventricular pressure (A2-LVPmin) were recorded. All variables were followed up to 1 month after occlusion of the shunt. One hour after occlusion, there was an incomplete return to baseline values of the echocardiographic left ventricular dimension (+12 +/- 8% of baseline value, p < 0.01). Despite a 31 +/- 14% (p < 0.001) increase of the posterior wall thickness after removal of the volume overload, tau or ventricular relaxation showed no change from control values. In contrast, the early filling wave was blunted, suggesting diminished ventricular suction. A2-MVO (p < 0.01) and A2-LVPmin (p < 0.05) lengthened well above baseline values for up to 1 week after occlusion of the shunt. Over the following month, the volume-induced hypertrophy regressed, and indexes of early ventricular filling resumed control values. CONCLUSIONS: We conclude that early after removal of a chronic volume overload, the resultant increase of wall thickness is not associated with impaired relaxation but that viscosity and inertia caused by the increased mass-to-volume ratio will impair early ventricular filling.

Animals↗
PubMed1991

Development of a genetically engineered vaccine against feline leukemia virus infection.

A genetically engineered subunit vaccine against FeLV infection was developed. The protective immunogen in the vaccine was a purified recombinant protein containing the entire amino acid sequence of FeLV subgroup A gp70 envelope protein. The optimal adjuvant was determined to be a highly purified saponin, QS-21, derived from Quillaja saponaria Molina. A vaccine formulation containing the recombinant protein, QS-21, and aluminum hydroxide was tested in specific-pathogen-free kittens and was shown to induce neutralizing antibodies as well as appreciable antibody responses to native gp70 by enzyme immunoassay and protein (western) immunoblot analysis and of whole virus preparations.

Adjuvants, Immunologic↗
PubMed1991

Vaccination of cats experimentally infected with feline immunodeficiency virus, using a recombinant feline leukemia virus vaccine.

A group of 15 cats experimentally infected with a Swiss isolate of feline immunodeficiency virus (FIV) and a group of 15 FIV-negative control cats were inoculated with an FeLV vaccine containing recombinant FeLV-envelope. High ELISA antibody titer developed after vaccination in FIV-positive and FIV-negative cats. Vaccinated and nonvaccinated controls were later challenge exposed by intraperitoneal administration of virulent FeLV subtype A (Glasgow). Although 12 of 12 nonvaccinated controls became infected with FeLV (10 persistently, 2 transiently), only 1 of 18 vaccinated (9 FIV positive, 9 FIV negative) cats had persistent and 2 of 18 had transient viremia. From these data and other observations, 2 conclusions were drawn: In the early phase of FIV infection, the immune system is not depressed appreciably, and therefore, cats may be successfully immunized; a recombinant FeLV vaccine was efficacious in protecting cats against intraperitoneal challenge exposure with FeLV.

Animals↗
PubMed1991

Endoscopic treatment by snare electrocoagulation prior to Nd:YAG laser photocoagulation in 85 voluminous colorectal villous adenomas.

The association of endoscopic resection with Nd:YAG laser photocoagulation was used to treat benign colorectal villous adenomas. Eight-five patients were included: 49 with surgical contraindications, 35 for whom surgical resection appeared to be too hazardous, and 1 who refused surgery. Forty-five tumors had an axial extension between 1 and 3 cm, and 40 tumors had an axial extension of at least 4 cm. Diathermic snare resection was performed to remove large tumoral fragments prior to laser photocoagulation of the residual flat lesions. Treatments were repeated every 15 days until total tumor destruction was achieved. A carcinoma was detected in biopsy specimens obtained during endoscopic treatment of five patients. Two patients were lost to follow-up. Treatment results could be analyzed in 78 patients. Successful treatment was achieved in 67 patients. Tumor destruction was complete in 77 percent of patients who had lesions of at least 4 cm diameter and in 93 percent of patients with smaller lesions. The axial extension of the tumor was the main factor affecting the results of treatment. No major complications occurred. During the average 103-week follow-up period, 21 percent of the patients with total tumor destruction had a recurrence. The risk of recurrence was correlated with the number of initial treatment sessions and previous surgery treatment. It would appear that the treatment with endoscopic resection prior to Nd:YAG laser photocoagulation is a safe and effective method in the destruction of colorectal villous adenomas.

Adenoma↗
PubMed1991

Identification of conserved and variable regions in the envelope glycoprotein sequences of two feline immunodeficiency viruses isolated in Zurich, Switzerland.

The nucleotide sequences of the envelope (env) coding regions of two strains of the feline immunodeficiency virus isolated in Zurich, Switzerland (FIVZ1, FIVZ2) have been analysed. In addition, the complete sequence of the FIVZ1 isolate has been determined. Comparisons have been made with the previously published sequences of three North American isolates (PPR and the Petaluma strains FIV34TF10 and FIV14). The isolate FIVZ1 was very similar to the Petaluma strains of FIV and may represent a clonal derivative acquired by 'contamination'. Overall there are between 2.6% and 15.1% amino acid changes in the env gene products of the five isolates. Of the Zurich isolates, FIVZ2 exhibited the greatest divergence to the other viruses and based on its genotype, phenotype and origins probably represents a new isolate of FIV. Possibly the viruses diverged only recently from a common ancestor. Some 31 of the 33 cysteine residues and 17 of the 21 potential N-linked glycosylation sites of the FIV34TF10 env gene product were conserved among all five isolates. The open reading frame 3 (ORF3, or D) which overlaps the env gene (but is encoded in a different frame) has an ATG codon downstream of a potential splice acceptor site in all five isolates, supporting the view that it encodes a viral gene product. In ORF3 of FIVZ1 a stop codon was located 16 amino acids upstream of the stop codon of ORF3 of the other isolates. The ORF4 (or G) of isolate FIVZ2, thought to be the second coding exon of an FIV rev-like gene, contained a nucleotide deletion in amino acid 45 of ORF4, resulting in a--1 frameshift at this position. Comparison of the LTR sequences of the five isolates identified conserved promoter/enhancer elements. A potential stem-loop structure was identified in the R region of the LTRs of all the isolates, despite the heterogeneity of nucleotide sequences in that region. Such structures (TAR) are present in analogous regions of other lentiviruses and are responsible for tat-mediated trans-activation.

Amino Acid Sequence↗
PubMed1991

Genetically-engineered subunit vaccine against feline leukaemia virus: protective immune response in cats.

A recombinant retroviral subunit vaccine has been developed that successfully protects cats from infectious feline leukaemia virus (FeLV) challenge. The antigen used is a non-glycosylated protein derived from the envelope glycoprotein of FeLV subgroup A, expressed in Escherichia coli. This recombinant protein, rgp70D, includes the entire exterior envelope protein gp70, plus the first 34 amino acids from the transmembrane protein p15E. The vaccine consists of purified rgp70D absorbed on to aluminium hydroxide and used in conjunction with a novel saponin adjuvant. Cats immunized with this formulation developed a strong humoral immune response, including neutralizing and feline oncornavirus-associated cell membrane antigen antibodies. Vaccinated animals showed an anamnestic response upon intraperitoneal challenge with FeLV-A, and were protected from viral infection. In contrast, the control animals developed viraemia shortly after the challenge, which in most cases became chronic. Formulation of the same antigen with other widely used adjuvants elicited poor protective immune responses in cats.

Adjuvants, Immunologic↗
PubMed1991

Differential modulation of spontaneous and evoked neurotransmitter release from hair cells: some novel hypotheses.

It has been generally accepted that even in the absence of mechanical stimulation of the transductional elements, a resting depolarizing current exists which is ultimately responsible for the spontaneous release of neurotransmitter. Movement of the transductional elements modulates this resting current and thereby the evoked release of neurotransmitter occurs. Recent data from our laboratory and others have led us to question whether the relationship between spontaneous and evoked neurotransmitter release is as simple as stated. Indeed, a variety of experimental manipulations appear to influence the two modes of release differently. Examination of our results and the results of others has led us to four hypotheses: 1. the two modes of neurotransmitter release are processed differently by the hair cells; 2. cyclic AMP is involved in spontaneous but not evoked neurotransmitter release; 3. there is a positive feedback step involving an excitatory amino acid and its receptor on the hair cell in evoked neurotransmitter release and; 4. different pools of calcium are involved according to the mode of release. Accordingly, there may be several biochemical steps between the transductional movement of the stereocilia at the apex of the hair cells and the ultimate release of the neurotransmitter at the base of these cells. Some of these biochemical steps are different depending on whether the mode of release is spontaneous or evoked. These biochemical steps may amplify or at least interact with the biophysical processes previously described in the hair cells.

Acetylcholine↗
PubMed1991

A simple biological index for detection of alcoholic liver disease in drinkers.

To make liver biopsy unnecessary in certain cases, PGA (P, prothrombin time; G, gamma-glutamyl transpeptidase; A, apoliprotein AI), a simple biological index combining a specific test for severe liver disease (prothrombin time), a sensitive test of alcoholic liver disease (serum gamma-glutamyl transpeptidase), and a test for liver fibrosis (serum apolipoprotein AI), was evaluated in a training sample of 333 drinkers and validated in 291 other drinkers. All patients underwent an intercostal liver biopsy, and the specimen was independently read by two pathologists. The PGA index varied from 0 to 12. When PGA was less than or equal to 2, the probability of cirrhosis was 0% and the probability of normal liver or minimal changes 83%. Conversely, when PGA was greater than or equal to 9, the probability of normal liver or minimal changes was 0% and the probability of cirrhosis 86%. These values did not vary between training and validation periods, between asymptomatic vs. symptomatic subjects or between PGA at admission vs. PGA 1 week later. This index could be useful for general practitioners in identifying subjects at high risk for severe alcoholic liver disease.

Adult↗
PubMed1991

[Esophagitis in progressive systemic scleroderma. Prevalence and risk factors in forty-six patients].

Forty-six patients with progressive systemic sclerosis (37 women and 9 men) were successively evaluated by endoscopy, manometry, and esophageal pH monitoring. Fourteen patients (30.4 percent) had erosive esophagitis. Twenty-four patients were symptomatic; nineteen patients complained of dysplagia. Erosive esophagitis was significantly more frequent in symptomatic patients than in asymptomatic patients (50.0 percent vs 9 percent, P less than 0.01) and especially in patients complaining of dysphagia (57.9 percent vs 11.1 percent, P less than 0.01). Erosive esophagitis was not correlated with symptoms of gastroesophageal reflux. Abnormal esophageal motility was found in 34 patients (73.9 percent). Occurrence of erosive esophagitis was not linked with esophageal dysmotility. In patients with erosive esophagitis lower esophageal sphincter pressures were significantly lower than those in patients without erosive esophagitis. Twenty-four hr-pH monitoring showed pathological gastroesophageal reflux in 20 patients (43.5 percent). Erosive esophagitis was more frequent in patients with pathological gastroesophageal reflux than in patients with normal gastroesophageal reflux (50.0 percent vs 15.4 percent, P less than 0.02) especially in patients with pathological supine nighttime gastroesophageal reflux (61.5 percent vs 18.2 percent, P less than 0.01). Our data suggest that symptoms, dysphagia, diminished lower esophageal sphincter pressures, and pathologic nighttime gastroesophageal reflux are reliable predictors of the presence of erosive esophagitis in patients with progressive systemic sclerosis.

Adult↗
PubMed1991

Independent risk factors for hepatocellular carcinoma in French drinkers.

The aim of this study was to assess whether markers of hepatitis B virus or hepatitis C virus infection are independent risk factors for hepatocellular carcinoma in drinkers after adjustment for three known risk factors: cirrhosis, age and male sex. Among 2,015 consecutive drinkers admitted, hepatitis C virus antibodies were found by sensitive radioimmunoassay in 1,259. The following five factors have been identified and ranked as risk factors for hepatocellular carcinoma in unidimensional and regression analysis: cirrhosis (p less than 0.001), age (p less than 0.001), male sex (p less than 0.001), presence of HBsAg (p less than 0.001) and presence of hepatitis C virus antibodies (p less than 0.03). Among drinkers with cirrhosis, the patients with hepatocellular carcinoma were older (64 +/- 11 yr vs. 56 +/- 9 yr; p less than 0.001), were more often male (93% vs. 65%; p less than 0.0001) and had higher prevalence of HBsAg (9% vs. 2%; p = 0.02) and hepatitis C virus antibodies (41% vs. 26%; p = 0.02). A simple algorithm permitted us to identify a high-risk population of drinkers: the male cirrhotic patient older than 50 yr. The relative risk of hepatocellular carcinoma in this selected population was 17.7 (95% confidence interval = 9.0 to 37.5; p less than 0.0001). From a pragmatic point of view, the detection of HBsAg or hepatitis C virus antibodies, although independently associated with hepatocellular carcinoma, is not useful in increasing the diagnostic value of this algorithm because of the poor sensitivity of these tests. The weak relationships observed between hepatitis C virus antibodies and hepatocellular carcinoma needs confirmation by more accurate tests.

Age Factors↗
PubMed1990

[Efficacy of Pygeum africanum extract in the medical therapy of urination disorders due to benign prostatic hyperplasia: evaluation of objective and subjective parameters. A placebo-controlled double-blind multicenter study].

The efficacy of an extract of Pygeum africanum in the treatment of micturitional disorders due to benign prostatic hyperplasia was tested in a multicentre double-blind trial versus placebo. Capsules containing 50 mg of Pygeum africanum extract or placebo were administered at a dosage of 1 capsule in the morning and 1 capsule in the evening over a period of 60 days. 263 patients were included in this study, which was carried out in 8 centres in Germany, France, and Austria. Evaluation was mainly based on quantitative parameters such as residual urine, uroflowmetry and the precise monitoring of diurnal and nocturnal pollakiuria. Treatment with the Pygeum africanum extract led to a marked clinical improvement: a comparison of the quantitative parameters showed a significant difference between the Pygeum africanum group and the placebo group with respect to therapeutic response. The characteristic subjective symptoms of micturitional disorders, which were evaluated by the patients in a qualitative manner, were also significantly improved by administration of Pygeum africanum extract. Overall assessment at the end of therapy, showed that micturition improved in 66% of the patients treated with Pygeum africanum extract, as compared with an improvement of 31% in the placebo group. The difference was significant at the statistical level of p less than 0.001. During therapy with Pygeum africanum extract, gastrointestinal side effects occurred in 5 patients. Treatment was discontinued in three of those cases.

Double-Blind Method↗
PubMed1990

Long-term results of treatment of vascular malformations of the gastrointestinal tract by neodymium YAG laser photocoagulation.

This study reports long-term results of treatment of vascular malformations of the gastrointestinal tract by neodymium YAG (Nd-YAG) laser photocoagulation in 60 patients (13 patients with hereditary hemorrhagic telangiectasia and 47 patients with angiodysplasias) and examines prognostic parameters of bleeding recurrence in 47 patients with angiodysplasias. In patients with hereditary hemorrhagic telangiectasia, the transfusion requirements were lower only in the second and third year following therapy than in the year before therapy; however, these differences were not significant. In patients with angiodysplasias, a median number of one laser session (range 1-8) was necessary to destroy angiodysplasias. A blood loss recurred in 15 patients. The cumulative probability of remaining free of blood loss recurrence at 24 months and at 54 months was 61 +/- 9%. Three parameters had an independent prognostic value, the initial number of angiodysplasias (P less than 0.02), the presence of coagulation disorders (P less than 0.05), and age (P less than 0.05).

Aged↗