Biomedical subjects
Publications and source records attributed to A Aubert.
We describe the application of a new two-stage endoscopic procedure for removal of a retained stent in the common bile duct (Type 1 foreign body in Ban's classification). The technique involves sphincterotomy and placement of the endoprosthesis.
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.
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.
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.
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.
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.
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.
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.
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.
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).
Infarction was provoked in the dog by introducing a copper coil into the left anterior descending coronary artery. Eight groups, each of 6 dogs, were studied which received various treatments and were evaluated after 24 hours or 1 week. The anatomical extent of infarction was measured by the triphenyltetrazoliumhydrochloride method; size was evaluated angiographically by the centerline, chord and radial method and by ejection fraction. The extent of infarction was similar in groups studied after 24 hours and 1 week. Angiographical changes were most marked after 24 hours, and the ejection fraction was related to the extent of infarction (r = -0.5; P less than 0.02). Some parameters of the radial and centerline method showed also a relation to the extent of infarction (r = 0.47 to 0.57; P less than 0.05). After one week, the ejection fraction was no longer correlated to the extent of infarction. The correlation between the parameters of the chord, radius and centerline method and the extent of infarction improved to r-values of 0.58 to 0.63 (P less than or equal to 0.01). There was no difference between the 3 methods.
SAG1, a rabies virus strain bearing one mutation which abolishes virulence for adult animals, was constructed from the SADBern strain of rabies virus which has previously been used as live vaccine for oral immunization of foxes. SAG1 also bears an antigenic mutation which serves as an additional marker of the strain. Studies on mice and four species of wild rodents showed that SAG1 is totally avirulent whereas SADBern is still pathogenic after intracerebral, intramuscular or oral inoculation and thus could cause cases of rabies. Trials of oral vaccination performed on foxes with SAG1 indicate that it is as effective as SADBern. The SAG1 strain represents a significant progress in the search for an efficient and safe live rabies for the oral immunization of wild animals.
STUDY OBJECTIVE: The aim was to record diastolic transmitral pressure gradients at high sensitivity to quantitate the effect on transmitral pressure gradients of changing the heart rate. DESIGN: Diastolic left atrial and left ventricular pressures were recorded at high sensitivity (40 mm Hg = 10 mm recorded deflection) in control conditions (heart rate 70 beats.min-1) and after intravenous administration of atropine or isoprenaline (heart rate 110 beats.min-1). A special ventricular extrasystole protocol enabled the zero level of the transmitral pressure gradients to be unequivocally determined at high heart rates. The effect of atropine and isoprenaline on the pressure gradients, absolute diastolic pressures, and diastolic time intervals was investigated. EXPERIMENTAL MATERIAL: 16 mongrel dogs, 16-25 kg, were used. MEASUREMENTS AND RESULTS: Below a heart rate of 110 beats.min-1, four distinct periods were identified, during which a pressure gradient existed. During early and late diastole, a positive pressure gradient was consistently followed by a negative pressure gradient. Mean negative pressure gradient during early diastole correlated with the pressure difference of rapid filling wave (r = 0.72, p less than 0.01) and with mean positive pressure gradient during early diastole (r = 0.66, p less than 0.01). At a heart rate of 110 beats.min-1, isoprenaline augmented, while atropine reduced, the mean positive pressure gradient during early diastole without affecting the time interval over which the gradient occurred. This divergent action of the two drugs was related to their different effects on the decay of left ventricular pressure, which fell faster and deeper with isoprenaline but not with atropine. Both drugs shortened the time interval of the negative pressure gradient in early diastole without significantly affecting the mean negative pressure gradient during this period. In late diastole, atropine augmented the mean positive pressure gradient more than isoprenaline, reflecting the higher afterload after administration of atropine. Neither drug affected the time interval of the positive pressure gradient. As a result of a shortening of the P-R interval, isoprenaline shortened the time interval of the negative pressure gradient and reduced its mean value. Such an effect was not observed with the dose of atropine used. CONCLUSIONS: We conclude that a pressure gradient reversal in early diastole is always observed below a heart rate of 110 beats.min-1 and that isoprenaline and atropine affect the pattern of transmitral pressure gradients in a different way.
Serum apolipoprotein A-I measurement was compared in alcoholic patients according to presence or absence of chronic pancreatitis and liver fibrosis. Among alcoholic patients without liver disease, apolipoprotein A-I was significantly lower in patients with chronic pancreatitis (157 +/- 70 mg/dl) than in patients without pancreatitis (209 +/- 74 mg/dl, p less than 0.001). In cirrhotic patients, apolipoprotein A-I was lower in patients with chronic pancreatitis (82 +/- 35 mg/dl) than in patients without pancreatitis (102 +/- 45 mg/dl), but this difference was not significant. The decrease of serum apolipoprotein A-I was independent of nutritional parameters whether or not there was cirrhosis. Immunohistochemical study of pancreatic samples with chronic pancreatitis showed that apolipoprotein A-I was located in the pancreatic fibrosis whereas lobules were unstained. This study suggests that apolipoprotein A-I is trapped by the pancreatic extracellular matrix and that this sequestration might explain, in part, the decrease of the serum apolipoprotein A-I.
In an attempt to assess the diagnostic values of serum gamma-glutamyltransferase (GGT) and mean corpuscular volume (MCV) variations as markers of liver disease and of abstinence in alcoholic patients, we compared 174 patients with alcoholic cirrhosis, 175 with noncirrhotic alcoholic liver disease and 67 patients with nonalcoholic cirrhosis. GGT and MCV values were checked three times, the day of admission, 7 days later, and on the last sample available during follow-up (1 to 12 months), and were compared according to the liver disease and abstinence. A decrease of GGT activity during the 1st week of hospitalization was noted in alcoholics with (-9 IU/liter) or without (-13 IU/liter) cirrhosis and not in nonalcoholic cirrhosis (+8 IU/liter), without MCV variations. During follow-up, median GGT activity was strikingly different in abstinent patients with (27 IU/liter) or without (21 IU/liter) cirrhosis and in nonabstinent patients (99 IU/liter and 123 IU/liter, respectively) (p less than 0.001). MCV decrease was noted in alcoholics whatever their abstinence or not, contrasting with the absence of decrease in nonalcoholic patients. For the diagnosis of alcoholism in cirrhotic patients, the positive predictive value (PPV) of a GGT or a MCV decrease during the 1st week of hospitalization was 0.82 and 0.78, respectively, and the negative predictive value (NPV) was 0.33 and 0.70, respectively. For abstinence during follow-up, the PPV of a GGT activity less than 50 IU/liter was 0.92 and the NPV was 0.65.(ABSTRACT TRUNCATED AT 250 WORDS)
In the light of the present serological tests, the etiology, clinical features and course of acute viral hepatitis were reviewed in 423 consecutive male patients. Follow-up started less than 15 days after the onset of jaundice and continued until recovery or for at least six months if recovery did not occur before them. The incidence of type A viral hepatitis decreased in France but remained high in North Africa and tropical areas. During the acute phase it differed from hepatitis type B by a lower aminotransferase level. Relapse, however, was more common, as was protraction of longer than six months. Recovery ultimately occurred. The specific IgM antibody persisted throughout the condition. Type B hepatitis differed from type A hepatitis by a mean quicker normalization of the biochemical disturbances. In the absence of superinfection by delta hepatitis virus or by a non-A, non-B virus, the progression to chronic liver disease was rare. The course of non-A, non-B hepatitis was very dissimilar according to the circumstances of occurrence. In epidemic cases rapid recovery occurred and no progression to chronicity was noted. In the other cases, relapse and chronicity were more frequent than for type A or B hepatitis. Type D hepatitis was characterized by more pronounced biochemical disturbances during the acute phase and by more frequent progression to chronicity in case of superinfection.
Improvement of cochleovestibular symptoms induced by trimetazidine (TMZ) has been evidenced by clinical studies. However, a poor knowledge of the physiopathology and the scarcity of experimental models contributed to making determination of the mode of action of the drugs difficult. We studied the effect, in vitro, of TMZ on the production of oxygen-derived free radicals using, as a biological model, the isolated semicircular canal of the frog. This model allows to exert separate control over the ionic composition of the endo- and perilymphatic fluids. The spontaneous activity of the afferent nerve fibers, as well as the endolymphatic potential, were recorded at rest. Three additional parameters were analyzed, while the semicircular canal was subjected to mechanical stimulation, i.e., ampulla potential, nerve potential and the evoked frequency of action potentials. Free radical generation induced by the administration of phenazine methosulfate (PMS, 10(-5) M, 15 min) into the perilymphatic compartment, leads to a deterioration of the production of endolymph and the release of this afferent neuromediator. Inversely, PMS has no influence whatsoever on the mechanisms of mechanical-electrical transduction. The addition of TMZ (10(-6) or 10(-5) M) in the perilymphatic compartment counteracts the harmful effects of free radicals on the various bioelectric activities. These results suggest that the beneficial action of TMZ observed during treatment of cochleovestibular disorders is due, at least in part, to the anti-oxidizing properties of the molecule of interest.
Between October 1986 and January 1989, 57 attempts of percutaneous transluminal valvuloplasty were made in 51 elderly patients, mean age 76.7 +/- 6.2 years, with symptomatic aortic stenosis; this included 3 failures and 6 repeat valvuloplasties. The procedure resulted in a significant immediate decrease of the peak-to-peak transaortic pressure gradient from 94.6 +/- 26.5 to 42.6 +/- 17.9 mm Hg (p less than 0.002) and an increase of the surface of the aortic valve from 0.4 +/- 0.1 to 0.6 +/- 0.2 cm2 (p less than 0.001). Cardiac output remained unchanged: 3.8 +/- 0.9 vs 3.8 +/- 0.8 lit/min. Complications included local vascular injury requiring surgical repair in 7 patients, cerebral events in 3 patients and disruption of the aortic annulus, the aortic wall and the pulmonary artery each in 1 patient, and resulted in 4 in-hospital deaths (8%). Follow-up data were available for all patients for a mean duration of 12.7 +/- 5.4 months. Fifteen patients (30%) died on average 9.0 +/- 4.9 months after discharge. Recurrence of symptoms and early restenosis were documented in the majority of the patients. Restenosis was successfully treated by repeat valvuloplasty in 4 and by valve replacement in 4 patients. Doppler echocardiography predicted the severity of the aortic stenosis before valvuloplasty and was very useful to assess follow-up results. Because of the limited hemodynamic results, the numerous procedural complications and the development of early restenosis balloon valvuloplasty of aortic stenosis should be restricted to selected symptomatic elderly patients.