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Biomedical subjects

J Victor

Publications and source records attributed to J Victor.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Value of thyroidectomy in amiodarone-induced hyperthyroidism. Apropos of 3 cases].

Amiodarone-induced hyperthyroidism in a relatively rare complication of long-term treatment with this molecule. It usually carries a good prognosis with regression being the rule after withdrawal of the drug although lethal forms have been reported. Conventional medical therapy (synthetic antithyroid drugs, steroids, betablockers) used in severe forms, is not always effective. In addition, amiodarone may be essential for the treatment of life-threatening, poorly tolerated arrhythmias, refractory to other forms of treatment. The authors report the cases of three patients treated with amiodarone for malignant arrhythmias who developed severe hyperthyroidism resistant to medical therapy and who were treated by total thyroidectomy. Surgery was followed by rapid resolution of the thyrotoxicosis without significant complications and immediate represcription of amiodarone. Thyroidectomy therefore seems a simple solution for amiodarone-induced hyperthyroidism allowing very rapid resolution of the hyperthyroidism and the possibility of immediate represcription of amiodarone.

Adult↗
PubMed1996

The Judet quadricepsplasty: a retrospective analysis of 16 cases.

Sixteen quadricepsplasties performed for severe extension contractures of the knee were reviewed. Preoperatively all cases showed a severe extension contracture with an average of 23 degrees flexion. Only two patients had more than 30 degrees flexion preoperatively. The average improvement in knee flexion at follow-up was 69 degrees with 11 (68.7%) patients achieving a final flexion of 90 degrees or more. In four cases there was a 15 degrees loss of terminal active extension. In one case a rapid recurrence of the contracture was seen during the initial postoperative weeks. One patient developed a deep infection, and another an acute compartment syndrome.

Adolescent↗
PubMed1996

[Is the presence of right ventricular high intensity signals sufficient for the diagnosis of right ventricular dysplasia?].

The aim of this study was to assess "morphological" MRI data (spin-echo) compared with cine-MRI in 10 patients with documented right ventricular dysplasia and 10 normal controls. Data was acquired with a 0.5 Tesla superconductor magnet associating sequences of spin-echo and gradient echo (cine-MRI). An abnormal high intensity signal was observed in spin-echo in 9 out of the 10 patients. They were present on the anterior and sub-tricuspid walls of the right ventricle (8/10) and in the pulmonary infundibulum (8/10). A dyskinetic zone corresponding to the abnormal signals was detected in 8 patients. In the control group, only one subject had an abnormal high intensity signal and no dyskinesis could be detected. The association of high intensity signals and dyskinesis would seem to be very specific of right ventricular dysplasia. On the other hand, a high intensity signal alone may be observed in apparently normal subjects and would seem to be less specific.

Aged↗
PubMed1995

Defective natural immunity: an early manifestation of human immunodeficiency virus infection.

Cytotoxicity mediated by natural killer (NK) and lymphokine-activated killer (LAK) cells may be of significance in host defense against viral infections. This study included 347 patients infected with human immunodeficiency syndrome virus (HIV) type 1 and 110 controls. The NK cell activity, either unstimulated or stimulated with interferon-alpha (IFN-alpha) or interleukin-2 (IL-2), and the LAK cell activity were suppressed in patients, but the NK/LAK cell activity did not differ between patients with AIDS and patients without AIDS. However, the IFN-alpha-stimulated NK cell activity and LAK cell activity were reduced in patients with symptoms of HIV disease (CDCIV) when compared with asymptomatic patients (CDCII+III). When the data were analyzed by multiple linear regression, the percentage of CD4+ cells had a positive effect on these two parameters in patients without AIDS, whereas the percentage of CD4+ cells had no significant effect on unstimulated and IL-2-stimulated NK cell activity in these patients. In controls and AIDS patients, the percentage of CD4+ cells had no effect on NK/LAK cell activity in multiple linear models. The total number of CD16+ cells was low in patients compared to controls, whereas the percentages of CD16+, CD56+, and CD16+CD56+ were either normal or elevated. Therefore, the decrease in NK cell subpopulations did not contribute to the observed depression in NK/LAK cell activity in vitro. It is concluded that natural immunity is suppressed in HIV-seropositive patients primarily because of a qualitative defect of the NK/LAK cells. This qualitative defect includes a reduced responsiveness to IFN-alpha, which is progressive until the onset of symptoms, and possibly related to the loss of CD4+ cells.

Adult↗
PubMed1995

Illusory contours activate specific regions in human visual cortex: evidence from functional magnetic resonance imaging.

The neural basis for perceptual grouping operations in the human visual system, including the processes which generate illusory contours, is fundamental to understanding human vision. We have employed functional magnetic resonance imaging to investigate these processes noninvasively. Images were acquired on a GE Signa 1.5T scanner equipped for echo planar imaging with an in-plane resolution of 1.5 x 1.5 mm and slice thicknesses of 3.0 or 5.0 mm. Visual stimuli included nonaligned inducers (pacmen) that created no perceptual contours, similar inducers at the corners of a Kanizsa square that created illusory contours, and a real square formed by continuous contours. Multiple contiguous axial slices were acquired during baseline, visual stimulation, and poststimulation periods. Activated regions were identified by a multistage statistical analysis of the activation for each volume element sampled and were compared across conditions. Specific brain regions were activated in extrastriate cortex when the illusory contours were perceived but not during conditions when the illusory contours were absent. These unique regions were found primarily in the right hemisphere for all four subjects and demonstrate that specific brain regions are activated during the kind of perceptual grouping operations involved in illusory contour perception.

Brain Mapping↗
PubMed1995

[Electrophysiological study for the diagnosis and prognosis of syncope of unknown origin].

OBJECTIVE: To evaluate, on the basis of long-term outcome, the value of electrophysiologic exploration for determining the cause of syncope of unknown origin after clinical examination and standard laboratory tests. METHODS: In 1985 and 1986, 109 consecutive patients with syncope of unknown origin underwent electrophysiologic exploration. The patients were divided into two groups. Baseline electrocardiogram was abnormal in 59 patients: cardiopathy (32%), ischemia (17%). In 44 of these patients, electrophysiologic exploration revealed major abnormalities requiring treatment (Group 1). No aetiology could be defined in 65 patients (Group 2). Patients were followed for 37 +/- 11 months. Three were lost to follow-up and 106 were retained for analysis. RESULTS: Morbidity and mortality were 25% and 16% respectively at the end of follow-up. Two sudden deaths were recorded, both in Group 1. Total mortality was greater in Group 1 (10 vs 6) so electrophysiologic exploration had defined a population at lower risk of sudden death and overall mortality. Relapse of syncope was observed in 27 patients (25% and 26% in Groups 1 and 2 respectively) due to rhythm disorders in 8, vasodepression in 1 and unknown origin in 18. CONCLUSION: The rate of recurrent syncope suggests these patients should have a second work-up in order to diagnose initially false negatives. Relapse raises the problem of electrophysiologic abnormalities and multifactorial mechanisms causing syncope of unknown origin.

Adult↗
PubMed1995

Carotid sinus syndrome: acute hemodynamic evaluation of a dual chamber pacing mode.

Cardiac pacing is the treatment of choice in patients with carotid sinus syndrome (CSS). Three different pacing modes were tested in 20 patients (16 males, 4 females; mean age 75 +/- 9 years) with documented symptomatic CSS. Three carotid sinus massages (CSM) were performed in each supine patient successively paced in random order in: DDI--the reference pacing mode; DDD--automatic mode conversion (DDD/AMC) allowing automatic switching from AAI to DDD when AV block occurs; DDD/AMC plus atrial acceleration (DDD/AMC+acc); and OOO (CSM without pacing) to determine whether the vasodepressive effect was still present 10 minutes after the preceding CSM. Intraarterial blood pressure was continuously monitored. Results were expressed as the value of the mean systolic BP at T0 + 3 s + 6 s ... T0 + 30 s divided by the value of the mean systolic blood pressure prior to onset of CSM. The drop in arterial blood pressure was more severe in the DDI mode than in DDD/AMC (P < 0.001) and DDD/AMC+acc (P < 0.0001) in 20 patients. In the OOO mode, the drop in arterial blood pressure was most marked and greater than in the DDI mode (P < 0.0001). The average time between start of the CSM and onset of the drop in blood pressure was the same in the three dual chamber modes. We conclude that the DDD/AMC mode significantly improves the vasodepressor response to CSM compared to the DDI mode. There is a current trend favoring DDD/AMC+acc over DDD/AMC.

Aged↗
PubMed1995

[Hyperthyroidism induced by amiodarone and hyperthyroidism induced by iodine. Histologic, immunohistochemical and ultrastructural aspects].

Amiodarone is a widely-used anti-arythmic drug that induces an iodine overload and, in 1 to 23% of the patients, a thyrotoxicosis. In a few cases, the thyrotoxicosis may be refractory to conventional pharmacological therapy, thus leading to thyroidectomy. We report the thyroid gland pathology in 5 thyroidectomies that were performed for uncontrolled thyrotoxicosis, induced by amiodarone (4 cases) and by Colchimax, another iodine-rich drug (1 case). Two cases have been studied by electron microscopy. Pathologic findings were: [1] colloid transformation of the parenchyma, [2] areas of follicular disruption with numerous foamy macrophages in the colloid, [3] regenerative areas and [4] a moderate T lymphocytic infiltration. No lysosomal lamellar inclusion body was found by electron microscopy. These lesions may be rather specific of an iodine toxicity. The pathogeny is still misunderstood, and probably complex. It may essentially involve toxic mechanisms, as well as immunologic or allergic mechanisms.

Adult↗
PubMed1994

Hepatitis A vaccine. A new convenient single-dose schedule with booster when long-term immunization is warranted.

A total of 162 anti-HAV-negative healthy adults were immunized with a single high dose (1440 ELISA units = 1 ml) of inactivated hepatitis A vaccine and a booster was given at month 6. Antibodies were measured after modification of a commercial ELISA kit, enabling quantification of titres down to 6 mIU ml-1. After 14 days, 96% of vaccinees had positive anti-HAV titres (> 20 mIU ml-1), and after 30 days all vaccinees had seroconverted. The geometric mean titres were 150 mIU ml-1 and 380 mIU ml-1 respectively. The booster dose at month 6 elicited a dramatic (25-fold) increase in antibody titres from 125 to 3090 mIU ml-1. Thus a single dose may be a convenient alternative to immunoglobulin for inducing rapid seroprotection, with a booster dose at month 6 ensuring long-lasting protection.

Adolescent↗
PubMed1994

[Arrhythmia and conduction defects in polymyositis].

The prevalence of cardiac complications of dermatomyositis and polymyositis is generally underestimated. The authors report the case of heart block as the presenting symptom of the disease, situated in the atrioventricular node. Initially paroxysmal, it eventually became permanent. It was associated with atrial (fibrillation and flutter) and ventricular hyperexcitability (ventricular tachycardia in runs). Myocardial biopsy provided histological proof of the cardiac disease and the definitive link between the nodal conduction defect and the polymyositis.

Adult↗
PubMed1994

[Value of magnetic resonance imaging in cardiac sarcoidosis. Apropos of a case].

The authors report the value of magnetic resonance imaging (MRI) in a case of cardiac sarcoidosis presenting with syncopal ventricular tachycardia (VT). The images were acquired in a monomorphic multiplane echo spin sequence. A 25 millisecond interval was chosen for the weighted T1 sequence. A second weighted T2 sequence using an interval of 70 milliseconds was then performed. The acquisitions were recorded in these planes axial, sagittal and coronal. The thickness of the sections was 8 mm. MRI was useful in locating the exact site and extent of the lesions; this enabled the operators to perform "guided" endomyocardial biopsies. In the weighted T1 sequences, these biopsies showed zones of increased intramyocardial signal density, more pronounced on the second weighted T2 sequences. Moreover, it was possible to follow up the outcome of these lesions with steroid therapy and observe their partial regression. These non-specific appearances may be observed in all inflammatory conditions but, in the context of systemic sarcoidosis, are very suggestive of cardiac involvement. In view of the clinical latency of cardiac sarcoidosis and its poor prognosis, the non-invasive character of MRI should make this a routine investigation in all patients with systemic sarcoidosis.

Adult↗
PubMed1994

[Tachycardia with wide QRS. Limitations of electrocardiographic criteria in patients treated with anti-arrhythmia agents].

The diagnosis of ventricular tachycardia is difficult, often requiring endocavitary investigation to obtain proof. Many authors have attempted to define criteria used to distinguish between ventricular tachycardia and supraventricular tachycardia with wide QRS in the surface electrocardiogram. These criteria have been determined in patients not taking antiarrhythmic drugs. The authors report the case of a patient treated with flecainide for atrial fibrillation and hospitalised because of faints and tachycardia with wide complexes. The diagnosis of ventricular tachycardia was justified by surface electrocardiogram but was eliminated by subsequent endocavitary electrophysiological studies. The use of anti-arrhythmic drugs thus limits the applicability of electrocardiographic criteria in cases of tachycardia with wide QRS.

Anti-Arrhythmia Agents↗
PubMed1993

Limitations of quantitative radionuclide bone scanning in the evaluation of total knee replacement.

To establish the value of quantitative radionuclide bone scanning after total knee replacement, 21 patients were scheduled for examination. Eight patients were scanned more than 1 year after surgery (group 1), and 13 within the first postsurgical year (group 2). Ratios were calculated for three regions of interest. The ratio was defined as the counts per pixel for each region of interest, normalized by dividing them by the counts per pixel of the ipsilateral femoral shaft. There was no significant difference in uptake between control subjects and patients in group 2, indicating that the test was not reliable within this time period. No statistical difference was found between the uptake scores in groups 1 and 2, demonstrating that an uninterpretable period of 1 year is perhaps too short. Using a ratio of more than three, seen more than 1 year after surgery as pathologic, a sensitivity of 100%, a specificity of 33%, and an accuracy of 75% was found. Quantitative bone scanning is a very sensitive test for detecting complications, but it is nonspecific in diagnosing loosening of total knee arthroplasties. The value of quantitative scanning presumably lies in the follow-up of patients as an objective method for the evaluation of sequential scanning. Nevertheless, radionuclide data need to be interpreted in correlation with clinical and radiologic findings.

Evaluation Studies as Topic↗
PubMed1993

A novel antineuronal antibody in stiff-man syndrome.

Two-thirds of stiff-man syndrome (SMS) patients harbor an autoantibody specific for a 64-kD species of glutamic acid decarboxylase (GAD), the rate-limiting enzyme in GABA synthesis. We assayed SMS antisera from two patients with SMS for the presence of anti-GAD antibodies using Western blot, immunohistochemical, and enzymatic analyses. Both SMS antisera recognized an 80-kD antigen present in human and rat neuronal extracts, and failed to recognize the 64-kD GAD species. Immunohistochemistry demonstrated neuronal binding identical to that reported with anti-GAD antibodies. Both sera depleted GAD activity from brain extracts. Our analysis indicates that these SMS antisera differ from previously reported SMS antisera by recognizing a novel 80-kD antigen, and suggests that they contain antibodies directed against either a species of GAD different in size from the 64-kD enzyme, or a protein that co-immunoprecipitates with GAD.

Adult↗
PubMed1993

[Thallium 201 myocardial scintigraphy and left branch block. Comparative value of exercise test and dipyridamole test].

Stress Thallium 201 myocardial scintigraphy in patients with left bundle branch block often shows reversible septal perfusion defects even in the absence of coronary artery disease. This phenomenon seems more common when the patients have tachycardia. With the working hypothesis that dipyridamole stress testing, which does not greatly increase the heart rate, would be more appropriate than exercise stress testing to unmask coronary artery disease in this condition, the authors compared the results of two Thallium 201 scintigraphies performed after exercise and then after dipyridamole under the same conditions three weeks later, in 67 patients with complete left bundle branch block. Scintigraphy showed one or more reversible perfusion defects in 64/67 patients after exercise but only 32/67 patients after dipyridamole (p < 0.001). There was poor uptake in the septal region in 59 patients (88%) after exercise and in 25 patients (37%) after dipyridamole (p < 0.001). The specificity was evaluated in 23 patients estimated to have no coronary artery disease. If only unequi vocal perfusion defects were considered, the specificity after dipyridamole was higher than that after exercise, increasing from: 35% to 83% for septal defects (p < 0.01); 65% to 96% for anterior wall defects (p < 0.05); 61% to 87% for inferior wall defects (p < 0.05); 57% to 91% for apical defects (p < 0.01); 17% to 83% overall (p < 0.001). Lower values but with a comparable difference were observed when all forms of hypofixation (even minimal) were taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗