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Biomedical subjects

N Boyer

Publications and source records attributed to N Boyer.

71 records · Page 4Linked to original sources
PubMed1991

Recombinant human alpha-interferon in patients with chronic non-A, non-B hepatitis: a multicenter randomized controlled trial from France.

We have conducted a multicenter randomized controlled trial comparing two doses of recombinant human alpha-interferon for efficacy in 60 patients with chronic non-A, non-B hepatitis. The source of infection appeared to be transfusion in 30 patients, intravenous drug abuse in 16 patients and was unknown in 14 patients. Patients were randomly assigned to no treatment or to treatment with either 1 or 3 MU of alpha-interferon given three times a week for 24 wk. Forty-five patients (75%) were positive for antibody to hepatitis C virus. During the 24-wk treatment period, mean serum ALT levels decreased in both treatment groups, but the decrease was statistically significant only in the 3 MU group. However, at 24 wk, the proportion of patients with normal ALT levels was similar in the 3 MU group (39%) and the 1 MU group (45%), and both were significantly higher than in controls (0%). Repeat liver biopsy specimens showed a significant decrease in the severity of histological changes in the 3 MU group but not in the 1 MU group or in controls. Responses to alpha-interferon did not correlate with patient's age, gender, source of infection, pretreatment serum ALT, presence of anti-hepatitis C virus or cirrhosis. After treatment, the mean ALT levels rose in both treated groups. The proportion of patients with normal ALT levels at wk 48 was 28% in the 3 MU group and 20% in the 1 MU group. In conclusion, a dose of 3 MU was superior to 1 MU of alpha-interferon given three times weekly for 24 wk in inducing improvements in serum ALT levels and liver histological examinations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Recombinant human gamma-interferon in patients with chronic active hepatitis B: pharmacokinetics, tolerance and biological effects.

Pharmacokinetics, tolerance and biological effects of human recombinant gamma-interferon were studied in 12 patients with chronic active hepatitis B. Serum concentrations of gamma-interferon were measured by radioimmunoassay in four patients after a subcutaneous injection of 10 million U (0.5 mg); the peak serum concentration of gamma-interferon (29 +/- 7 U/ml) was reached after 5 to 8 hr and gamma-interferon remained detectable for 24 to 36 hr. Twelve patients received recombinant gamma-interferon, 2.5 to 10 million U daily, for 4 mo. All suffered from a dose-dependent, flulike syndrome similar to that induced by alpha-interferon. Recombinant gamma-interferon induced a marked increase of serum ALT and a significant decrease of serum hepatitis B virus-DNA. Serum hepatitis B virus-DNA disappeared in one patient during administration of recombinant gamma-interferon. Serum hepatitis B virus-DNA disappeared in four additional patients, and HBeAg disappeared in two patients during the 12 mo after administration of recombinant gamma-interferon. These results indicate that subcutaneous injection is suitable for administration of recombinant gamma-interferon and that recombinant gamma-interferon has an antiviral effect in patients with chronic active hepatitis B.

Adult↗
PubMed1990

Is the response to recombinant alpha interferon related to the presence of antibodies to hepatitis C virus in patients with chronic non-A, non-B hepatitis?

The purpose of this study was to determine whether the response of serum alanine aminotransferase (ALT) to recombinant alpha-interferon was related to the presence or absence of antibodies to hepatitis C virus (anti-HCV) in patients with chronic non-A,non-B hepatitis. A group of 65 patients with chronic non-A, non-B hepatitis was studied. The source of contamination was blood transfusion or administration of blood products in 32, intravenous drug addiction in 14 and unknown in 19. The patients received 1, 3 or 5 MU of recombinant alpha-interferon, three times a week, for 6 months. A complete response was defined as normal ALT by the end of recombinant alpha-interferon treatment. Sera collected before treatment were tested for anti-HCV with an enzyme immunoassay. The overall percentage of anti-HCV positive patients in the study group was 75%. There was no difference between the anti-HCV positive and the anti-HCV negative patients before the treatment with respect to age, sex ratio, source of contamination, serum albumin, prothrombin, bilirubin, ALT or prevalence of cirrhosis. In the anti-HCV positive and the anti-HCV negative groups, there was no difference in the proportion of patients receiving the 1, 3 or 5 MU dosage. The percentage of patients with complete response was not different in anti-HCV positive patients (48%) and in anti-HCV negative patients (50%). There was also no difference in the kinetics of the decrease of mean serum ALT levels between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Specific Inhibition of Lignification in Bryonia dioica: Effects on Thigmomorphogenesis.

Rubbing-induced lignification in Bryonia dioica internodes is significantly impaired by N(o-hydroxyphenyl) and N(o-aminophenyl) sulfinamoyl tertiobutyl acetate, specific inhibitors of cinnamyl alcohol dehydrogenase, an enzyme which is strictly associated with lignin monomer synthesis. Along with the reduction of lignification, these inhibitors counteract the inhibition of elongation due to rubbing. These results indicate that lignification participates in the thigmomorphogenetic growth response of Bryonia dioica internodes. In a general way, the data point to the causal role of lignification in the limitation of plant growth.

Journal Article↗
PubMed1983

Effect of Lithium on Thigmomorphogenesis in Bryonia dioica Ethylene Production and Sensitivity.

Rubbing internodes of Bryonia dioica plants reduced their ethylene production but increased their capacity to convert 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. These results were explained by the previously shown rubbing-induced decrease of indoleacetic acid, which controls the level of ACC synthase, and by the increase of membrane-associated peroxidases which would participate in the conversion of ACC-ethylene. Pretreatment of the plants with Li had no significant effect on control plants but counteracted the rubbing-induced decrease of ethylene production and diminished the capacity of the internodes to convert ACC to ethylene. Exogenously applied ethylene induced an increase of peroxidase activity similar to that caused by rubbing. Inasmuch as both effects were reduced by Li, it was concluded that Li inhibition of thigmomorphogenetic processes was essentially due to a Li inhibition of the effect of ethylene formed in response to mechanical stimuli. The decreased ethylene production and ACC conversion capacity in the presence of Li were explained by a cellular redistribution of peroxidases.

Journal Article↗
PubMed1981

Hypocotyl Growth and Peroxidases of Bidens pilosus: EFFECT OF COTYLEDONARY PRICKINGS AND LITHIUM PRETREATMENT.

Pricking one cotyledon of young Bidens pilosus plants induces rapid inhibition of hypocotyl growth, essentially in its middle portion. Analysis of soluble peroxidases indicates rapid changes (increase of activity) in basic isoenzymes followed by more progressive enhancement of the acidic ones. Pretreatment of the plants with lithium prevents the inhibition of elongation due to pricking as well as the peroxidase changes. The phenomenon is similar to the previously described thigmomorphogenetic process in Bryonia dioica.

Journal Article↗
PubMedDate not supplied

Natural history of hepatitis C and the impact of anti-viral therapy.

The hepatitis C virus (HCV) infects some 170 million people worldwide and is responsible for approximately 20% of cases of acute hepatitis and 70% of cases of chronic hepatitis. Acute hepatitis is icteric in only 20% of patients and is rarely severe. Eighty five per cent of the infected patients develop chronic infection which is generally asymptomatic. Among the HCV chronic carriers, 25% have persistently normal serum alanine aminotransferase (ALT) levels despite having detectable HCV-ribonucleic acid in serum, 75% have elevated ALT levels. While the majority of patients with mild chronic hepatitis have a slowly progressive liver disease, the patients with moderate or severe chronic hepatitis may develop cirrhosis within a few years. In patients with HCV-related cirrhosis, the incidence of hepatocellular carcinoma is 2-5% per year. HCV-related end-stage cirrhosis is currently the first cause of liver transplantation. Treatment with the combination of interferon-alpha and ribavirin induces a sustained virological response in roughly 40% of the patients. The virological response is associated with a biochemical response and histological improvement. It is believed that the decrease of necroinflammatory liver lesions induced by anti-viral therapy in responders, is associated with a decreased risk of development of cirrhosis and hepatocellular carcinoma

Acute Disease↗
PubMedDate not supplied

[Preliminary evaluation of morbidity due to S. haematobium and S. mansoni in the area of the future Adjarala Dam in Benin].

The aim of this study was to provide a preliminary assessment of morbidity due to schistosomiasis in the area of the future Adjarala Dam in Benin. We included 412 schoolchildren from five villages in the study. The mean age of the children was 9.4 +/- 2.3 years and the sex ratio (F/M) was 0.94. These children underwent parasitological examination. The children provided urine samples, which were examined by eye, filtered and tested for blood and protein. Stool samples were examined using Kato's technique and an ultrasound scan of the urinary tract was performed. We carried out a survey of snails at the possible transmission sites of all the villages, with a view to identifying the intermediate hosts. We detected S. mansoni and S. haematobium in the area. Urinary schistosomiasis was mesoendemic (prevalence of 19.7%) whereas schistosomiasis due to S. mansoni was hypoendemic (prevalence of 3. 9%). Ultrasound scans showed that 28% of the children had bladder lesions and that 2.5% were carriers of hydronephrosis. We compared the diagnostic performances of the various indirect indicators of morbidity. We found that a history of hematuria was the most sensitive indicator (88%) but that the sensitivity of this indicator differed significantly according to the sex of the child. Hematuria >= 1+ was the most effective indicator. Snail surveys showed that Biomphalaria pfeifferi and Bulinus globosus were present in the area.

Age Factors↗
PubMedDate not supplied

Acetylcholinesterase activity changes in medial vestibular complex after hemilabyrinthectomy in the rat.

Acetylcholinesterase (AchE) activity was studied in pigmented rats 6 h to 1 y after hemilabyrinthectomy. A strong reduction of this activity was localized in the rostrocaudal extent of both the prepositus hypoglossi nucleus and the medial vestibular nucleus (that is, medial vestibular complex: VCm) ipsilateral to the lesion 6 h after the lesion. This deficit persisted within some areas dispersed throughout this complex 3 w and 1 y postoperatively. This result supports the hypothesis that the asymmetry of AchE activity in VCm could be necessary for vestibular compensation and provides an additional model for functional plasticity in the central nervous system.

Acetylcholinesterase↗