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Biomedical subjects

M Mimouni

Publications and source records attributed to M Mimouni.

At least 55 records · Page 3Linked to original sources
PubMed1994

Kinetic studies of rat liver adenosine kinase. Explanation of exchange reaction between adenosine and AMP.

Rat liver adenosine kinase can catalyze an exchange reaction between adenosine and AMP in the absence of ATP (Bontemps, F., Mimouni, M., and Van den Berghe, G. (1993) Biochem. J. 290, 679-684), suggesting a classical ping-pong mechanism. Contrary to expectations, formation of a phosphorylenzyme intermediate could not be demonstrated by incubating the enzyme with [gamma-32P] ATP. Although initial velocity measurements in function of the concentration of adenosine or Mg.ATP, at various fixed concentrations of Mg.ATP or adenosine, generated parallel line patterns, inhibition studies revealed that competitive inhibition was only observed between ADP and ATP. This indicates an Ordered Bi Bi mechanism in which ATP binds first to the enzyme, and ADP is released last. The adenosine-AMP exchange reaction was found to be potently stimulated by ADP, and the basal exchange reaction, i.e. measured in the absence of added ADP, could be accounted for by a slight (0.001%) contamination by ADP of analytical grade AMP. The ADP requirement of the adenosine-AMP exchange reaction explains its occurrence in an Ordered Bi Bi mechanism. Stimulation of the exchange reaction between AMP and adenosine by increasing concentrations of ADP/ATP, and stimulation followed by inhibition of the exchange reaction between ADP and ATP by increasing concentrations of AMP/adenosine, corroborated the proposed mechanism.

Adenosine↗
PubMed1994

Outcome of Israeli adolescents with anorexia nervosa whose ambulatory treatment was abruptly interrupted during the Gulf War.

We recently presented the theory that parents should be intensively involved in the treatment of adolescents with anorexia nervosa during the acute re-feeding period and during follow-up. Thirteen anorectic patients with a mean age of 14.6 years (range: 12.6-16.5 years) were being treated in our pediatric day-care unit in Israel according to this treatment model when the Gulf War broke out. Because of the war, treatment was abruptly interrupted for approximately 6 weeks. Immediately after the war the patients were re-evaluated. We found that all of them maintained their weight, and two had even continued to gain weight. These results encouraged us to assume that our treatment model, based on intensive parental involvement especially during the acute re-feeding period, was effective.

Adolescent↗
PubMed1994

Stunting of growth in anorexia nervosa during the prepubertal and pubertal period.

The growth charts of 15 patients with anorexia nervosa during the prepubertal and pubertal period were carefully reconstructed. All 15 (13 females, 2 males) had been suffering from anorexia nervosa for at least 6 months prior to referral. Mean age at referral was 13.3 +/- 1.3 years and mean duration of anorectic symptoms was 17 +/- 8 months. In all 15 cases growth arrest had been present for 13 +/- 8.5 months prior to admission. During the follow-up period, catch-up growth to different degrees was observed in the 13 patients (11 females, 2 males) who remained under treatment for at least 1 year. On the assumption that stunting of growth during the prepubertal and pubertal period is a very frequent, if not a constant, sign of anorexia nervosa of 6 months duration or more, it could be considered an additional criterion for diagnosis of the disease. The projected height should be included in the calculation of ideal weight. Since patients with growth arrest are usually referred first to a general pediatrician or a pediatric endocrinologist, it is recommended that a detailed history of caloric intake, as well as the attitude of the patient to food, be obtained in each case in order to confirm the diagnosis of anorexia nervosa.

Adolescent↗
PubMed1994

Pediatric telephone advice: a new medical service in Israel.

Although controversy still exists about dispensing medical advice over the telephone, such services are widely offered by pediatricians in the USA. In Israel, however, such services have not yet been developed. In a joint project of the Moked Keshev (a private medical help line) at Magen David Adom (national ambulance service) and the Children's Medical Center of Israel, the first pediatric telephone advice service in Israel was established. In this study we analyzed 512 consecutive incoming calls received during the first 11 months of service operation. Of these, 42% of calls concerned children in the 1 month to 1 year age group. Unexpectedly, calls were almost evenly distributed throughout the week with a slight decrease on Fridays and Saturdays (sabbath), and 45.7% of the calls were received during the morning shift. The three most common reasons for contact were: of a general nature such as fever (23%), gastrointestinal problems (19%), and medical questions (18%). In only 20.7% of the cases were the patients advised to go to the nearest hospital emergency department, emphasizing the non-emergent nature of the calls. At the time of follow-up (within 24 h), patient status was assessed as: improved (73.7%), same (22.6%), and worse (3.8%). Of those who became worse, none required an emergency department evaluation. The present study demonstrates that a Pediatric Telephone Advice Service in Israel is technically functional, medically safe, and contributes to the health management of children.

Adolescent↗
PubMed1994

Celiac disease associated with systemic lupus erythematosus.

Celiac disease in children has been occasionally reported to be associated with various disorders such as arthritis, cutaneous vasculitis and diabetes mellitus. We report on a 12-year-old girl with celiac disease, diagnosed at 1 year of age, who developed systemic lupus erythematosus. This association has not yet been reported in children.

Celiac Disease↗
PubMed1994

A prospective evaluation of pediatric patients with syncope.

Fifty-eight children with syncope were evaluated prospectively to determine the characteristics of syncope in the pediatric age group and the yield of various diagnostic tests. The age at first syncope ranged from 0.5 to 15 years. Twenty-five children presented after a single episode and 33 after multiple episodes. Ten had a history of breath-holding spells. Nineteen had a family history of syncope. A diagnosis was established in 53 patients (91%): vasodepressor (31), cardioinhibitory (13), tussive (3), hyperventilation (2), and mixed syncope (4). In five patients (9%), the cause remained unknown. The diagnosis was established from the history in 45 cases, by a positive oculocardiac reflex in 11, and by the head-up tilt test in four. We conclude that the cause of most cases of pediatric syncope is vasodepressor or cardioinhibitory and can be diagnosed by good history-taking. Costly evaluations are rarely necessary.

Adolescent↗
PubMed1993

Phosphorylation of adenosine in anoxic hepatocytes by an exchange reaction catalysed by adenosine kinase.

The elevation of adenosine levels induced by anoxia in isolated rat hepatocytes has been shown to result mainly from an arrest of the recycling of the nucleoside by adenosine kinase [Bontemps, Vincent and Van den Berghe (1993) Biochem. J. 290, 671-677]. To assess the activity of the latter enzyme in intact hepatocytes, incorporation of radioactive adenosine into the cells' adenine nucleotides was measured. Unexpectedly, despite the near-absence of ATP in anoxic cells, 40% of 50 microM [8-14C]adenosine was still incorporated into adenylates over 5 min. Moreover, whereas unlabelled and labelled adenosine were utilized in parallel in normoxic cells, uptake of [8-14C]adenosine did not correspond to a net disappearance of adenosine in anoxic cells. Addition of 1 mM unlabelled adenosine to anoxic hepatocytes in which the adenine nucleotides had been prelabelled with [U-14C]adenine induced an immediate loss of their radioactivity. The latter was recovered in the form of adenosine, but the size of the adenylate pool was not modified. Taken together, these results suggest the occurrence of an exchange reaction between AMP and adenosine. Incubation of Sephadex G-25-filtered high-speed supernatants of rat liver with 20 microM [8-14C]adenosine, 10 mM MgCl2 and 1 mM AMP resulted in the labelling of AMP in the total absence of ATP. This labelling was influenced by effectors of both adenosine kinase and cytosolic IMP-GMP 5'-nucleotidase; the latter is known to catalyse an exchange reaction [Worku and Newby (1982) Biochem. J. 205, 503-510]. Chromatography of cytosolic fractions of rat liver on DEAE-Sepharose, followed by Sephacryl S-200 and AMP-Sepharose, demonstrated that the exchange reaction between adenosine and AMP co-purified with adenosine kinase. It is concluded that incorporation of labelled adenosine into adenine nucleotides should not be considered to be proof of adenosine kinase activity in anoxia.

5'-Nucleotidase↗
PubMed1993

Spectral analysis of heart rate in vasovagal syncope: the autonomic nervous system in vasovagal syncope.

Spectral analysis of heart rate fluctuations was used to investigate the role of the autonomic nervous system in the pathogenesis of vasovagal syncope. Nine adolescents with a history of at least three episodes of vasovagal syncope and nine age-matched healthy controls were studied. All subjects were tested in supine position and at a 60 degrees inclination for 60 min or less if syncope developed. Blood pressure and heart rate were measured, while the ECG and respiration traces were recorded on magnetic tape for later spectral analysis. Baseline heart rate was lower in control subjects than in patients, increased with tilt in both groups, and remained lower in the control subjects throughout the experiment. Baseline systolic and diastolic blood pressure was similar in both groups. Diastolic blood pressure initially increased with tilt in all subjects and decreased significantly thereafter in patients. Pulse pressure was lower in patients throughout the experiment. The heart rate power spectra displayed a higher baseline level of low frequency fluctuations in the control group. The high frequency fluctuations component was similar in all subjects. The results of the test, regarding haemodynamic parameters and autonomic control of the heart rate, as expressed by low and high frequency fluctuations, are consistent with a reduced sympathetic reserve in the individuals with previous episodes of syncope.

Adolescent↗
PubMed1992

3-Methylglutaconic aciduria: a new variant.

3-Methylglutaconic aciduria has been described in two distinct syndromes. In one there was deficient 3-methylglutaconyl coenzyme A hydratase in fibroblast extracts where the only clinical manifestation was retarded speech development. In the second syndrome, the enzyme activity was normal but prominent neurological deterioration was noted. We describe two siblings with 3-methylglutaconic aciduria with normal enzyme activity who had choreoathetoid movements, optic atrophy, and mild developmental delay. The boy demonstrated developmental improvement in his second year of life, and his sister developed well, with normal school performance. These patients represent a new clinical variant of the second syndrome with a relatively favorable prognosis.

Acidosis↗
PubMed1991

Inflammatory pseudotumor in childhood. A diagnostic and therapeutic dilemma.

We describe a case of inflammatory pseudotumor of the lower abdomen in a young child. The urinary bladder and abdominal wall were involved, and the pseudotumor simulated a malignant sarcomatous tumor. Surgical excision was undertaken, and the outcome was favorable. This rare tumor simulates a true neoplasm both clinically and morphologically and presents a diagnostic and therapeutic dilemma. Our case and a review of the literature indicate that an effort should be made to perform a radical excision. This is considered the treatment of choice except if it requires a mutilating procedure.

Abdominal Muscles↗
PubMed1991

Breast mild jaundice: natural history, familial incidence and late neurodevelopmental outcome of the infant.

Jaundice associated with breast feeding is a frequent problem facing the paediatrician. Despite numerous reports on this subject, the natural history, familial occurrence and late neurodevelopment of children with breast milk jaundice remain unclear. The follow up of 60 infants with breast milk jaundice showed that there are two bilirubin peaks, on the 4th and 5th day and on the 14th-15th day of life. In the infants with uninterrupted breast feeding, the hyperbilirubinaemia disappeared slowly and could still be detected 12 weeks after birth. The familial incidence of 13.9%, indicating that in some cases a unique genetic factor is expressed. Late neurodevelopment or hearing defects were not observed, thus enabling the paediatrician to encourage continuation of breast feeding in most cases of healthy infants with breast milk jaundice.

Bilirubin↗