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Biomedical subjects

J Bloch

Publications and source records attributed to J Bloch.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Dependence, abuse and misuse of drugs: knowledge and attitudes of private physicians in the Ile-de-France].

BACKGROUND: The rise in drug consumption and poorly adapted prescription practices are currently a growing problem. In the face of this trend, "L'Union Professionnelle des Médecins Libéraux d'Ile-de-France" investigated the awareness and the attitude of physicians towards drug dependency, abuse and misuse. METHODS: One hundred physicians and 50 specialists, randomly selected, were contacted by phone. They were asked to give their own description of dependency, abuse and misuse based on patients' attitudes. They were to describe cases of their patients classifying them according to each category. In the second part of the phone interview, the physicians were to give their view about existing and potential tools to solve these problems. RESULTS: Dependency, abuse and misuse problems were well known and frequent: 94% of physicians have such experience and among those, 60% saw such a patient more than once a week. The population concerned by these problems were generally middle-aged women with chronic disease. Misuse behavior was less easily identified (53% of the physicians described such patients). They generally concerned young men, most often drug addicts. From a global point of view, psychotropes were the most frequently misuse drugs, followed by the pain drugs and nsaids. These types of drugs are used routinely, some of them being sold without prescription. Diseases concerned were essentially psychiatric disorders, sleeping troubles and long lasting pains well classified. To face these problem, physicians recommend a dialogue between medical members and patients as well as a changing in professional (physicians and pharmacists) behavior such as firmness, education and listening. CONCLUSION: Situations evoked during the survey were frequent but non systematically discerned as damageable. As a matter of fact, these observations are only a piece of an "intuitive" estimation of the risk versus benefit of the prescription of the drugs mentioned above. Actual regulation and control tools seem to be somewhat irrelevant to solve the problem.

Adult↗
PubMed1999

Seroprevalence of herpes simplex virus type 2 antibodies in an STD clinic in Paris.

Our objective was to evaluate the seroprevalence of herpes simplex virus (HSV)-2 and HSV-1 in a population of men and women attending the STD clinic of Hôpital St-Louis (Paris, France). Four hundred and eighty-seven patients (264 men and 223 women) were tested for HSV-2 and HSV-1 antibodies by specific enzyme immunoassay (EIA) (Smithkline-Beecham Biologicals). Univariate and multivariate analyses were carried out for correlations with clinical, socio-epidemiological and behavioural data. HSV-2 seroprevalence was 55% (44.7% in men, 67.3% in women). HSV-1 seroprevalence was 93% (94.7% in men, 91% in women). The predictive factors of HSV-2 seropositivity being female (OR: 3.37), age (OR: 1.04), country of origin (Central Africa OR: 3.52, North Africa OR: 1.36), history of genital herpes (OR: 10.97), hepatitis B virus (HBV) markers (OR: 1.92) and hepatitis C virus (HCV) markers (OR: 3.96). The only protective factor was HSV-1 seropositivity (OR: 0.25). The predictive factors of HSV-1 seropositivity were only the country of origin (Central Africa OR: 2.95, North Africa OR: 1.83) and the absence of genital herpes (OR: 11.01). Only 23 (8.6%) HSV-2 seropositive patients had a history of genital herpes. This study underlines the very high HSV-2 seroprevalence of patients with STDs, only a few of whom have a history of genital herpes. Detection and counselling is urgently needed for these patients.

Adolescent↗
PubMed1999

[Feasibility of drug use detection among individuals 15-25 years of age in community medicine].

The objective of this work is to study the feasibility of the detection of drug use or misused substances during a visit with a municipal doctor, and to describe the interrogatory strategies used spontaneously by doctors. One tenth of the clients aged 15-25 of the 26 participating doctors, (the majority of them men visiting the doctor for a psychological problem), showed a "warning" signal and were detected. The doctors often chose to approach the problem of drugs directly and detected usage in two-thirds of the cases. Cannabis was most often concerned, but the use of psychotropic drugs with alcohol was the case in one-third of the subjects interrogated. On the other hand, a certain frustration was felt by the doctors because of the difficulty of approaching the root problems and of acquiring psychotherapeutic monitoring.

Adolescent↗
PubMed1999

[Use of GEE for modeling censored correlated data: application to the study of risk factors for withdrawal of totally implantable vascular access devices in cystic fibrosis].

BACKGROUND: The proportional hazards model proposed by Cox for modeling censored data is not suited for correlated delays, for instance when several events can be observed on each subject. METHODS: To analyze correlated delays, we propose to use a log-linear marginal model equivalent to Cox model. Correlations are taken into account through the use of Liang and Zeger's Generalized Estimating Equations (GEE) and of their robust variance estimator. An advantage of this method is that it can be implemented through the SAS GENMOD procedure. When ties are observed, we propose to use multiple imputations, creating M data sets without ties from the original one. RESULTS: This method is applied to a retrospective survey on the risk of withdrawing totally implantable vascular access devices (TIVAD) because of complication in cystic fibrosis patients: 265 TIVAD implanted in 200 patients were observed. Risk factors were characteristics of the device or of the patient. Results obtained with the robust variance estimator and ten imputations show that the use of the device for taking blood (vs exclusive perfusion of antibiotics), polyurethane catheter (vs. silicon), use of counterpressure for upkeeping and pulmonary colonization by Pseudomonas Aeruginosa are significantly associated to withdrawal. Under the Cox model which does not account for the correlations, some conclusions differ because the robust variance of the estimators is smaller than the variance obtained under the working assumption of independent delays. CONCLUSION: This approach allows the modeling of correlated survival data with SAS software. Our results illustrate the necessity of accounting for existing correlations.

Catheters, Indwelling↗
PubMed1998

The ideal position of sacral transpedicular endplate screws in Jackson's intrasacral fixation. An anatomic study of 50 sacral specimens.

STUDY DESIGN: This study directly measures the ideal point of insertion and direction of sacral screws in the Jackson intrasacral fixation. OBJECTIVE: To design a template for safe positioning of transpedicular endplate screws that does not require fluoroscopy. SUMMARY OF BACKGROUND DATA: Screw and rod insertion into the sacrum as described by Jackson requires careful intraoperative fluoroscopic or radiographic control. The technique can *be difficult and demanding, especially in the case of severe pelvic obliquity. No anatomic data based on cadaveric studies are available to aid in the described technique for screw insertion. METHODS: Fifty dry sacrums were used. On each bone, the length of the intrasacral portion and the ideal direction of transpedicular endplate pins introduced at the originally described point of insertion were measured in reference to the plane formed by the two posterior sacral foramen and the posterior arch of S1. The limit angles in each direction, where the pin perforated the cortex outside of the S1 endplate, were noted. Then, the point of insertion of a pin with the ideal angles was progressively modified to determine the limits of the safe insertion area. The 95% confidence interval was reduced to the smallest safe angle. RESULTS: The safe angles were 54.3 degrees to 57.9 degrees for the sagittal plane, 47 degrees to 50 degrees for the coronal plane, and between 46.9 degrees and 49.7 degrees for the horizontal plane. CONCLUSIONS: A "cylinder of safety" for the transpedicular endplate screws was determined. Its coordinates are related to the sacrum and not to the sacral position. This allowed for a template to be designed, the efficiency of which will have to be confirmed by anatomic and clinical studies.

Adult↗
PubMed1998

Evaluation of a new low-dose digital x-ray device: first dosimetric and clinical results in children.

BACKGROUND: A new low-dose digital X-ray device, based on Charpak's Nobel prize-winning multiwire chamber, enables the production of images at very low doses. Objectives. To present the first dosimetric and clinical results. MATERIALS AND METHODS: The analysis was performed on 93 children with scoliosis and 47 undergoing pelvic radiography. The comparative study between conventional X-ray and the new technique focused on three points: (1) the dose delivered by each system (2) the diagnostic information provided by each system and (3) comparison of image quality criteria with European guidelines. RESULTS: The mean ratio of conventional dose to that of the low-dose technique was 13.1 for the spinal examination and 18.8 for the pelvis. There was no significant difference in diagnostic information available from each modality, but there was a slight difference in quality criteria in favour of the conventional technique. CONCLUSION: This new device allows spectacular dose reduction, consistent with adequate clinical information. Improvements of the prototype will lead to extension of potential indications and industrial development.

Child↗
PubMed1998

Alcohol or drug use and compliance with safer sex guidelines for STD/HIV infection. Results from the French National Survey on Sexual Behavior (ACSF) among heterosexuals. Analyse des Comportements Sexuels en France.

BACKGROUND: Available literature shows that association of alcohol and/or drug use with unsafe sexual practices is not established, in contradistinction to the well-established association between such substance use and the sexual milieu itself. GOAL: To analyze these two kinds of associations in a population-based sample of heterosexuals in France. STUDY DESIGN: Cross-sectional telephone survey of the French adult heterosexual population in the early 1990s (n = 4213). RESULTS: Subjects at risk were more likely than those not at risk to have consumed alcohol before sex; this was not the case for drug use. However, at-risk subjects who engaged in unsafe practice(s) were not more likely to have consumed alcohol or drugs. CONCLUSION: Alcohol consumption appears to be a marker for being in an at-risk situation in France and may be used as such by public health providers. In contrast, the association between alcohol/drug use and unsafe sexual practices is not supported by our study and thus conflicts with prevention strategies to increase compliance with safer sex through alcohol/drug abstinence.

Adolescent↗
PubMed1998

A mixed model for repeated dilution assays.

We propose a generalized linear mixed model to estimate and test marginal effects on titers repeatedly measured by serial dilution assays. The link is log-log and the titer is assumed to follow a gamma distribution. The parameters are estimated by generalized estimating equations. The marginal effects are tested by means of Wald and score tests, using the robust estimator of the variance. This approach avoids the problems arising from assays leading to nonestimable individual titers. Simulations were used to compare the Wald and score tests to Wilcoxon and Student t-tests. This method is applied to the comparison of the antiviral efficiency of three treatments against HIV.

Anti-HIV Agents↗
PubMed1997

Reduced final height and indications for insulin resistance in 20 year olds born small for gestational age: regional cohort study.

OBJECTIVE: To investigate whether the association between low birth weight and increased risk of developing impaired glucose tolerance, insulin resistance, hypertriglyceridaemia, and hypertension in middle age is apparent by the age of 20 in people born small for gestational age. DESIGN: Regional cohort study. SETTING: Maternity registry, Haguenau, France. SUBJECTS: 236 full term singleton babies born small for gestational age (birth weight or length, or both, below third centile) during 1971-8 and 281 with normal birth weight (between 25th and 75th centile). All subjects were contacted and evaluated at a mean (SD) age of 20.6 (2.1) years. MAIN OUTCOME MEASURES: Adult height; concentrations of glucose, insulin, and proinsulin during an oral glucose tolerance test; lipid and fibrinogen concentrations; and blood pressure. RESULTS: After sex and target height were adjusted for, subjects who had been born small for gestational age were significantly shorter at age 20 than those with a normal birth weight (men 4.5 cm shorter (95% confidence interval 6.0 to 3.0 cm); women 3.94 cm shorter (5.2 to 2.7 cm)). After sex and body mass index were adjusted for, mean plasma glucose concentration 30 minutes after a glucose load, fasting insulin concentration (in women), and insulin and proinsulin concentrations 30 and 120 minutes after a glucose load were significantly higher in subjects who had been born small for gestational age than in those with a normal birth weight. Mean lipid and fibrinogen concentrations and blood pressure were not different between the two groups. CONCLUSIONS: Intrauterine growth retardation has long term consequences such as reduced final height Raised insulin and proinsulin concentrations are present in young adults born small for gestational age and could be markers of early changes in insulin sensitivity.

Adolescent↗
PubMed1997

Cytotoxic T lymphocyte changes after HLA-DR match and HLA-DR mismatch blood transfusions.

In the present study, we analyzed transfusion-induced cytolytic T lymphocyte (CTL) changes in patients who received either a one-HLA-DR-match or a zero-HLA-DR-match pretransplant blood transfusion. Twenty-four nonimmunized naive patients awaiting kidney transplantation received one planned, HLA-typed blood transfusion. The frequencies of CTL precursors (CTLp) directed against blood donor cells and controls were evaluated before and sequentially at days 7, 28, and 60 after transfusion. Results showed that sharing one HLA-DR between donor and recipient did not prevent CTL sensitization. Indeed, (1) An increase of donor-specific CTLp frequencies was observed in 8 of 11 patients who received a zero HLA-DR match (71%), as well as in 9 of 13 patients who received a one-HLA-DR-match (69%) transfusion. (2) This increase occurred with similar kinetics in the two groups, as it was highly significant 7 days after transfusion (P=0.002 and P=0.0035 in the first and second groups, respectively) but transient; CTLp frequencies returned to pretransfusion levels by day 60 after transfusion in both groups. (3) Finally, the magnitude of this increase was similar in the DR-match and DR-mismatch groups. Thus, if it is confirmed, in clinical practice, that one DR match between the blood donor and the patient would improve the tolerance effect of pretransplant blood transfusion, this phenomenon is unlikely to be related to the prevention of CTL sensitization.

Blood Donors↗
PubMed1997

[Cyst of the ligamentum flavum of the lumbar spine: description of 6 cases].

Cysts of the ligamentum flavum of the lumbar spine have seldom been described. They are clearly visible in computed tomography as well as nuclear magnetic resonance, but are frequently wrongly diagnosed as ganglion or synovial cysts. The correct diagnosis is not feasible until after surgery. Such space occupying lesions can most often lead to uniradicular pain due to compression of a root. These cysts should be viewed as part of the degenerative process of the spine but not as tumor lesions. They need to be removed only in case of root entrapment. On the basis of six of our cases treated by surgery we describe the symptoms, imaging findings, operative techniques and pathological investigations.

Aged↗
PubMed1997

Nocturnal hypoglycemia in children and adolescents with insulin-dependent diabetes mellitus: prevalence and risk factors.

OBJECTIVES: To evaluate the prevalence and risk factors of nocturnal hypoglycemia (NH) in children and adolescents with insulin-dependent diabetes mellitus. STUDY DESIGN: A total of 150 patients, 87% of whom were receiving conventional therapy, were admitted to the hospital for one night. Blood glucose (BG) levels were measured hourly from 10 PM to 8 AM. RESULTS: The prevalence of NH was 47%; NH was asymptomatic in 49% of the cases. Risk factors were as follows: at least two episodes of severe hypoglycemia from onset of insulin-dependent diabetes mellitus (p = 0.0004), insulin dosage > 0.85 IU/kg per day (p = 0.02), more than 5% of BG measurements < or = 3.3 mmol/L during the last month of monitoring (p = 0.04). The risk decreased significantly with age (p = 0.0001). Both high predictive values and significant relative risk were found for BG thresholds < or = 5.2 mmol/L at dinner time (p < 0.0001) and < or = 6.7 mmol/L at 7 AM (p < 0.0001). When BG values at 10 PM were used, prediction of NH was weak. CONCLUSIONS: Nocturnal hypoglycemia occurred frequently in children and adolescents with insulin-dependent diabetes mellitus. Our study found risk factors that will help pediatricians to identify those children with a high risk of NH. Especially in these patients, counseling based on the BG values before dinner and early in the morning is indicated to reduce the prevalence of NH.

Adolescent↗
PubMed1996

[Remission of severe hypoglycemic incidents in young diabetic children treated with subcutaneous infusion].

BACKGROUND: Conventional insulin therapy for diabetes mellitus can be inadequate for controlling glycemia in young patients in whom the risk of hypoglycemia is particularly high. PATIENTS: A retrospective study comparing all the children under 6 years of age treated in our department by continuous subcutaneous insulin infusion (group P, n = 10, mean age: 3.7 years) to 17 children with conventional insulin therapy (group C, mean age: 5.1 years) was conducted during a mean period of 2 years. RESULTS: Mean insulin doses, HbAlc, pre-prandial and daily glycemic levels, measured at 0, 3, 6, 12, 18 and 24 months, did not differ significantly between both groups. Mean HbAlc levels remained < or = 8% in the two groups. There was no episode of severe hypoglycemia in group P vs ten episodes in group C (P < 0.05); this benefit was confirmed in those six children belonging to group P who had previously followed a conventional therapy: 11 episodes during the conventional period vs 0 episode during the pump period (P < 0.05). Nine out of ten families were very satisfied with the treatment by pump mainly because of a more comfortable life style and a reduction of parents' anxiety due to disappearance of severe hypoglycemias. The insulin pump therapy had some limits: cutaneous complications and technical ones were responsible for two keto-acidosis episodes (0.1 episode per year-patient) and a higher frequency of hospitalizations. In group C, hospitalizations were caused by severe hypoglycemias and unbalanced glycemic control. CONCLUSIONS: Insulin pump therapy could be indicated in young diabetic children at high risk of severe hypoglycemia under conditions of a specialized medical and educational supervision and knowledge of the limits of such a treatment.

Age Factors↗
PubMed1993

A combined intradural presigmoid-transtransversarium-transcondylar approach to the whole clivus and anterior craniospinal region: anatomic study.

Surgical exposure of the clivus is difficult because of its proximity to vital neurovascular structures. The anatomic bases of a new surgical approach to this area are discussed. A supra-auricular skin incision is extended toward the posterior border of the sternocleidomastoid muscle. The vertebral artery is exposed from C2 to the occiput unroofing the foramen transversarium of C1. The bone removal consists of a posterior temporal craniotomy, a suboccipital craniectomy, including mastoidectomy with sigmoid sinus unroofing, removal of the lateral margin of the foramen magnum, of the medial third of the occipital condyle, and retrolabyrinthine petrous drilling. Posterior retraction of the vertebral artery facilitates occipital condyle drilling. Intradural exposure of the petroclival region is achieved by L-shaped cutting of the dura with the long branch placed infratentorially anterior to the sigmoid sinus. Intradural exposure of the craniospinal/upper cervical areas is achieved by cutting of the dura medial to the distal sigmoid sinus and by longitudinal cutting of the dura anterior to the vertebral artery. This approach allows multiple ports of entry to the clivus with full control of the vertebrobasilar system, and of the dural sinuses, and is anatomically suited for controlled removal of tumors located in these areas. This approach, or segments of it, has been used successfully in the treatment of large neoplasms of the craniovertebral junction.

Journal Article↗