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Biomedical subjects

F Paycha

Publications and source records attributed to F Paycha.

At least 19 recordsLinked to original sources

[Computer-assisted diagnosis and therapy for glaucoma].

Boolean algebra, or combinatory analysis and their related computer routines, can provide invaluable help in resolving classic diagnostic problems. However complex each case may be, the diagnosis is always made from a finite set of data, and the fundamental problem is thus how to exploit this data. Invention no longer has a place in ascertaining a diagnosis. Traditional ways of reasoning are numerous, personal, and fragile, but fortunately redundant. They may give rise to four types of error: omission or mistake (an error of judgment), either during the semiotic or the dialectic stages. Whereas the physiological capacity of the human brain and memory only enables it to make a limited number of hypotheses concerning certain aspects of glaucoma, computer programs can take the total number of hypotheses into account, i.e., 3000. For every input the program explores each of the 3,000 items, thus eliminating the four types of error. The probabilistic nature of data, which compromises the confidence one can have in conclusions resulting from such complex reasoning, is treated by the adjusted probabilities. The use of such diagnostic aids, whose thesaurus is updated regularly, is reserved for ophthalmologists, the only authority capable of assessing the pertinence of the computer responses. Consequently, the specialist can rest assured that the patient has benefited from the most comprehensive and updated knowledge in medical science.

Glaucoma↗

Detecting silent coronary stenoses and stratifying cardiac risk in patients with diabetes: ECG stress test or exercise myocardial scintigraphy?

AIMS: To determine whether performing a myocardial scintigraphy immediately after a maximal electrocardiogram (ECG) stress test is effective in detecting silent coronary stenoses and predicting cardiovascular events. METHODS: Asymptomatic patients (n = 262) aged 57.6 +/- 8.8 years, with diabetes for 12.0 years (5-39) [median (range)] and no history of a cardiac event, underwent a maximal ECG stress test followed by a myocardial scintigraphy. The patients with an abnormal ECG stress test or abnormal imaging underwent a coronary angiography. Cardiac events were assessed in 250 (95.4%) patients followed for 37.8 months (3-101). RESULTS: The ECG stress test was abnormal in 54 patients. Among them, 18 had coronary stenoses and seven had a cardiac event. Despite a normal ECG stress test, the myocardial scintigraphy was abnormal in 42 additional patients, including 16 patients with coronary stenoses. Four of these 42 patients experienced a cardiac event. Follow-up showed a poor prognosis in subjects who were abnormal on the two tests. Univariate predictors of the 15 cardiac events were the ECG stress test [odds ratio (OR) 3.9, 95% confidence interval (CI) 1.3, 11.4, P = 0.008], myocardial scintigraphy (OR 3.8, 95% CI 1.3, 11.0, P = 0.009), coronary stenoses (OR 26.6, 95% CI 7.6, 90.7, P < 0.001), and peripheral or carotid occlusive arterial disease (OR 9.5, 95% CI 2.1, 42.5, P < 0.001). CONCLUSIONS: In the asymptomatic patients with diabetes, combining a myocardial scintigraphy with a maximal ECG stress test is effective in detecting more patients with coronary stenoses and predicting cardiovascular events. However, the ECG stress test has a good negative predictive value for cardiac events (97%), is cheaper, and should therefore be proposed first.

Cardiovascular Diseases↗

[Bone marrow reconversion and magnetic resonance imaging: case report].

INTRODUCTION: Bone marrow is divided into red marrow mainly constituted of hemopoietic cells and fatty yellow marrow. In some situations, yellow marrow may be converted into red marrow and this process is called marrow reconversion. Magnetic resonance imaging may be misleading with an invading bone marrow neoplastic process. EXEGESIS: We report a patient with non-Hodgkin's lymphoma with vertebral invasion. Clinical features at presentation were misleading with lower limbs migratory pain suggestive of inflammatory myositis. An MRI study of thigh muscles revealed femoral nodular lesions suggestive of bone marrow reconversion. CONCLUSION: Bone marrow reconversion is a physiologic and reversible process. Awareness of its radiographic features may help to avoid a diagnostic biopsy procedure.

Adult↗

Are silent coronary stenoses predictable in diabetic patients and predictive of cardiovascular events?

OBJECTIVES: We have previously shown that silent coronary stenoses (CS) were predictors of subsequent major cardiac events in diabetic patients with silent myocardial ischemia (SMI). The aim of this study was to determine their correlates and their prognostic value for other cardiovascular events. METHODS: 362 asymptomatic diabetic patients, without prior myocardial infarction, with > or =1 additional risk factor and a normal resting electrocardiogram underwent a myocardial scintigraphy to detect SMI. The patients with SMI subsequently underwent a coronary angiography to detect CS. A total of 345 (95.3%) patients were followed up for 41 +/- 24 months with regard to the occurrence of stroke, gangrene or a peripheral revascularization procedure, exercise occurrence of angina, and nonfatal arrhythmia. RESULTS: 121 patients had SMI and 44 had CS. The univariate correlates of CS were age > 65 years (Odds Ratio 2.1 [CI 95%: 1.1-4.0]; p=0.021), male gender (OR 3.1 [1.5-6.3]; p=0.001), smoking (OR 2.8 [1.4-5.6]; p=0.004), > or =2 risk factors (OR 2.1 [1.09-4.09]; p=0.024) and peripheral arterial disease (OR 3.2 [1.2-8.7]; p=0.018). Logistic regression showed that age > 65 years (p=0.034), male gender (p=0.001) and > or =2 risk factors (p=0.013) were independently associated with the presence of CS. The univariate predictors of the 16 minor events were peripheral arterial disease (OR 8.8 [2.7-28.5]; p<0.001), CS (OR 4.9 [1.7-14.2]; p=0.002), SMI (OR 3.7, [1.3-10.5]; p=0.009) and smoking (OR 3.2 [1.1-9.2]; p=0.024). In the multivariate analysis, arterial occlusive disease (p<0.001), smoking (p<0.036) and CS (p=0.044) were independent predictors of events. CONCLUSION: Silent CS predict major cardiac events but also other cardiovascular events and are more common in diabetic patients > 65 years-old, of male gender and with > or =2 risk factors.

Aged↗

[Usefulness of computers in diagnosis and therapy. The principle of the privileged hypothesis. The example of glaucoma].

AIM: Everyone sees only the errors of others, for diagnosis error proves difficult to detect inasmuch as medical reasoning is complex and subject to little supervision. MATERIAL: In the semiologic phase of everyday diagnosis, any sign can be overlooked: error by omission, or be poorly analyzed: error by confusion. Putting forward hypotheses based on observation is hazardous whenever data is used following the tenet that "these signs call up this disease," which is the opposite of "in this disease, these signs often or sometimes occur." Moreover, a comprehensive and detailed memorization is essential in order to avoid errors of omission: a hypothesis has been forgotten; or of confusion: a disease has been poorly memorized. METHOD: However vast it may be, the volume of data describing the miscellaneous pictures of glaucoma is finite and therefore usable on well-known computer devices. The nearly 1,000 pictures, Ma, Mb, etc., are described by 85 signs, sa, sb, etc. These signs are standard, objective, semiologically accurate, and independent. They are logically equivalent because the value of a given sign, of greater or lesser importance, only appears after the diagnosis has been ascertained. The pathological condition is exhibited as a set of enunciations: Ma=sa, sb, sc, etc. RESULTS: Written in Visual Basic, the program described herein runs on a basic PC workstation. The selection of predicates incorporating the signs of clinical observation suggests the likely diagnoses; probability calculus determines the favored hypothesis and its reliability. The etiological and differential diagnoses relying on one, two or three signs are outlined, as are therapies and contraindications. This information is comprehensive, detailed, pertinent, and updated.

Algorithms↗

Reducing the number of T3 orders in the Paris hospital network: towards better appropriatness of thyroid function test prescription.

In vitro thyroid function tests are among the most frequently prescribed laboratory procedures. Serum triiodothyronine (T3) tests are seldom necessary as a first-level measurement. Our objectives were to measure the proportion of T3 measurements relative to all in vitro thyroid function tests in a large hospital network and to investigate the contributions of various interventions to change prescribers'behavior. We performed two cross-sectional surveys in 1995 and 1998 in the 50 Paris University hospitals. Questionnaires were mailed to the heads of the 30 laboratories performing thyroid function tests. One-month orders of free and total thyroxine, free and total T3 and thyrotropin were recorded; changes in T3 measurement orders between the two periods were estimated and association with interventions were expressed as odds ratios and 95% confidence intervals. Twenty-five heads of laboratory responded to both surveys. In 1995, T3 measurements constituted 21% of in vitro thyroid function test ordering, which seems to us exceedingly high. The decrease in T3 measurement ordering observed in 1998 (15% of thyroid function test ordering) was independently associated with multiple behavioral changes: educational interventions, structured test form use and year of prescription.

Humans↗

Predictive value of cardiac autonomic neuropathy in diabetic patients with or without silent myocardial ischemia.

OBJECTIVE: The aim of this study was to determine the predictive value of silent myocardial ischemia (SMI) and cardiac autonomic neuropathy (CAN) in asymptomatic diabetic patients. RESEARCH DESIGN AND METHODS: We recruited 120 diabetic patients with no history of myocardial infarction or angina, a normal 12-lead electrocardiogram (ECG), and two or more additional risk factors. SMI assessment was carried out by means of an ECG stress test, a thallium-201 myocardial scintigraphy with dipyridamole, and 48-h ECG monitoring. CAN was searched for by standardized tests evaluating heart rate variations. Accurate follow-up information for 3-7 years (mean 4.5) was obtained in 107 patients. RESULTS: There was evidence of SMI in 33 patients (30.7%). CAN was detected in 33 of the 75 patients (38.9%) who were tested, and a major cardiac event occurred in 11 of them. Among these 75 patients, the proportion of major cardiac events in the SMI+ patients was not significantly higher than that in the SMI- patients (6 of 25 vs. 5 of 50 patients), whereas it was significantly higher in the CAN+ patients than in the CAN- patients (8 of 33 vs. 3 of 42 patients; P = 0.04), with a relative risk of 4.16 (95% CI 1.01-17.19) and was the highest in the patients with both SMI and CAN (5 of 10 patients). After adjusting for SMI, there was a significant association between CAN and major cardiac events (P = 0.04). CONCLUSIONS: In asymptomatic diabetic patients, CAN appears to be a better predictor of major cardiac events than SMI. The risk linked to CAN appears to be independent of SMI and is the highest when CAN is associated with SMI.

Adult↗

Lower-limb vascularization in diabetic patients. Assessment by thallium-201 scanning coupled with exercise myocardial scintigraphy.

OBJECTIVE: To investigate, by thallium-201 scanning, circulation in the muscles of the lower limb (LL) in diabetic patients without clinical peripheral vascular disease but with a high cardiovascular risk profile. RESEARCH DESIGN AND METHODS: A total of 80 diabetic patients (76 patients with type 2 diabetes, mean age 57.3 years, duration of diabetes 13.0 +/- 7.5 years) with more than one additional cardiovascular risk factor but no claudication were investigated. After stress testing, 1.5 MBq/kg thallium-201 was administered to perform myocardial single-photon emission computed tomography followed by LL scanning. Muscle blood flow was considered abnormal if the asymmetry in thallium-201 uptake between the two buttocks and/or thighs and/or calves was > 10%. RESULTS: Muscle perfusion defects were found in 42% of the patients, mainly in the calves. These defects correlated with retinopathy (P = 0.042) and the HbA1c level (P = 0.044). In patients with defects in the buttock and/or thigh, the prevalence of nephropathy and retinopathy was higher than in those with isolated defects in the calf (P = 0.032 and 0.023, respectively). CONCLUSIONS: This study suggests that LL scanning coupled with myocardial scintigraphy is a convenient method of investigating peripheral muscle circulation. Proximal perfusion defects in patients without clinical arterial disease are associated with increased prevalence of retinopathy and nephropathy and, therefore, may be due to microvascular disease of LL muscle. Distal defects may indicate silent macrovascular disease of the LL.

Adult↗

[Thyroid hormone determination at the Public Assistance Hospital of Paris: ordering, costs and opinions of physicians qualified in endocrinology].

OBJECTIVES: To determine the distribution of orders for hormonal tests assessing thyroid function in a hospital setting. To collect the opinion of physicians specialized in endocrinology concerning free triodothyronine (FT3) assessment. METHODS: Using a cross-sectional survey numbers of free thyroxine (FT4), total T4 (TT4), FT3, total T3 (TT3), and TSH tests were collected from the heads of laboratory assessing thyroid function in June 95 at the Assistance Publique-Hôpitaux de Paris (AP-HP). Cost for these tests was estimated. The physicians of the AP-HP specialized in endocrinology were asked through a questionnaire for circumstances justifying FT3 test ordering. RESULTS: Twenty-eight laboratories (93%) responded: 28455 measurements (TSH: 43%, FT4: 33%, TT4: 2%, FT3: 20%, TT3: 2%) were performed and were valued at 3.4 million French Francs. Proportions of T4 (36%) and T3 (20%) tests were lower in hospitals with an inpatient department of endocrinology than in hospitals with an outpatient clinic with specialists in endocrinology (T4: 36%; T3: 27%) or with no endocrinology unit (T4: 33%, T3: 27%); proportion of TSH tests was higher in hospitals with an inpatient endocrinology unit (respectively 44%, 40%, 32%). Forty-two endocrinologists (76%) from 21 departments answered. Follow-up of treatment with amiodarone and euthyroid sick syndrome were considered the only conditions justifying FT3 test ordering. CONCLUSION: Though the opinion of physicians specialized in endocrinology was not uniform regarding recommendations for TT3 or FT3 tests as a first-line measurement, the cost of these tests has been estimated at 650 thousand Francs for a month at the AP-HP.

Costs and Cost Analysis↗

Coronary artery responses to physiological stimuli are improved by deferoxamine but not by L-arginine in non-insulin-dependent diabetic patients with angiographically normal coronary arteries and no other risk factors.

BACKGROUND: Acetylcholine produces coronary artery (CA) constriction in diabetic patients, suggesting an impairment of endothelium-dependent dilation. In diabetes, multiple metabolic abnormalities may inactivate nitric oxide through oxygen free radical production. METHODS AND RESULTS: To examine the mechanism of this abnormal response, two physiological tests (ie, a cold pressor test [CPT] and coronary flow increase induced by an injection of 10 mg papaverine [PAP] in the distal left anterior descending CA) were performed before and after either intravenous L-arginine (625 mg/min x 10 minutes) or intravenous deferoxamine (50 mg/min x 10 minutes) in 22 normotensive nonsmoking diabetic patients with angiographically normal CAs and normal cholesterol. Coronary surface areas were measured with quantitative angiography. Before the administration of L-arginine or deferoxamine, CPT induced CA constriction in both groups (-14 +/- 10% and -15 +/- 11%, respectively; each P<.001), and PAP injection in distal LAD did not modify significantly proximal LAD dimensions. In the 10 diabetic patients receiving L-arginine, responses to CPT and PAP were not modified. Conversely, in the 12 patients receiving deferoxamine, CA dilated in response to the two tests (+10 +/- 9% after CPT and +22 +/- 7% after PAP, each P<.001). Intracoronary isosorbide dinitrate, an endothelium-independent dilator, produced similar dilation in the two groups (+47 +/- 19% and +41 +/- 15%, respectively; each P<.001). CONCLUSIONS: This study shows that (1) responses of angiographically normal CAs to CPT and to flow increase are impaired in diabetic patients; (2) abnormal responses are not improved by L-arginine, suggesting that a deficit in substrate for nitric oxide synthesis is not involved; and (3) deferoxamine restores a vasodilator response to the two tests, suggesting that inactivation of NO by oxygen species might be partly responsible for the impairment of CA dilation in diabetic patients.

Adult↗

Effect of psyllium on gastric emptying, hunger feeling and food intake in normal volunteers: a double blind study.

OBJECTIVE: To assess whether psyllium, a soluble dietary fibre, could, at an acceptable dose (7.4 g), delay gastric emptying of a low-calorie meal, and reduce hunger feeling and energy intake, without requiring intimate mixing with the meal. DESIGN: A double blind randomized cross over study with 14 normal volunteers, to evaluate the effect of this dose of psyllium on postprandial serum glucose, triglycerides and insulin levels, and on gastric fullness, hunger feeling and food intake. METHODS: Gastric emptying was measured using a standard double-radiolabeled 450 kcal meal and feelings by visual analogic scales. The postprandial serum glucose, triglycerides and insulin levels were also determined. RESULTS: No delay in the gastric emptying of the solid and liquid phases of the meal was observed with psyllium. After the meal, hunger feelings and energy intake were significantly lower during the psyllium session than during the placebo session (13% and 17% lower respectively; P < 0.05). Postprandial increase in serum glucose, triglycerides and insulin levels was less with psyllium than with placebo (P < 0.05). CONCLUSIONS: Psyllium reduces hunger feelings and energy intake in normal volunteers at reasonable dose and without requiring mixing with the meal. It does not act by slowing down the gastric emptying of hydrosoluble nutrients, but by increase in the time allowed for intestinal absorption, as suggested by the flattening of the postprandial serum glucose, insulin and triglycerides curves.

Adolescent↗

Pressure-heart rate responses to alpha-adrenergic stimulation and hormonal regulation in normotensive patients with obstructive sleep apnea.

Seven normotensive untreated patients with obstructive sleep apnea (OSA) and five control subjects without OSA were compared. Patients with cardiac dilation, chronic airflow limitation, liver and kidney disease, or diabetes mellitus were excluded. Change in pressure-heart rate relation to alpha-adrenergic stimulation (P-HRR), extracellular volume (ECV), and plasma volume (Vp) were measured during daytime. Plasma atrial natriuretic peptide (ANP), plasma renin and aldosterone concentrations were obtained at 1 hour intervals during the night. A mean apnea/hypopnea index (AHI) of 52.2 +/- 23.9/h and a mean lowest arterial oxygen saturation (SaO2) of 61.2 +/- 19.3% (mean +/- SD) were determined from polysomnographic monitoring in the patient group. Release of ANP was significantly higher during sleep in OSA patients than in control subjects (P < .01), with a maximum concentration between 4 and 6 AM in the former. Daytime ECV was significantly higher (P < .05) and Vp significantly lower (P < .05) in OSA patients. Night maximum concentration of ANP (max ANP) was negatively related to AHI (P < .05). P-HRR was negatively related to AHI (P < .05) and positively related to max ANP (P < .05). In conclusion, OSA syndrome alters hormonal system control of body fluid compartment regulation. The decreased response in night max ANP secretion in the most severe OSA patients could be explained by the smaller Vp observed in these patients, decreasing atrial and ventricular pressure loading. Furthermore, alteration of P-HRR, correlated to AHI and max ANP, strengthens the hypothesis that patients who develop hypertension are those in whom the protective mechanism of ANP release failed.

Adrenergic alpha-Agonists↗

Sacral insufficiency fractures: an easily overlooked cause of back pain in elderly women.

Sacral insufficiency fractures (SIF) that usually present as nonspecific pelvic or low back pain are often overlooked in the elderly. In a retrospective study conducted in a department of internal medicine, 16 patients with SIF were identified during a 6-year period. All patients were elderly women (mean age of 81 years) who presented with low back or pelvic pain. Radicular pain in the lower limb was common. Ten patients were bedridden. All 16 patients were osteopenic. Plain radiographs of the pelvis were nondiagnostic in 11 patients. Radionuclide bone scan showed a typical H-shaped pattern of increased uptake in 11 patients, and computed tomographic scan confirmed SIF (9/9 patients). With bed rest and analgesics, outcome was favorable in all patients. This study confirms the nonspecific presentation of SIF and the need to maintain a high index of clinical suspicion to make a prompt diagnosis and avoid unnecessary and sometimes invasive procedures.

Aged↗

[Factors of gastroesophageal acid reflux in severe obesity].

OBJECTIVE: To study in morbid obesity the relationship between the degree of gastro-oesophageal reflux (GER) and the excess of body weight, or the related factors such as the energy intake or the fat distribution (waist-hip ratio). METHODS: In 20 morbid obese subjects (body weight: 125 +/- 32 kg) consulting in a weight-loss programme, anthropometric measurements, 3-hr oesophageal pHmetry, double isotope labelled meal for studying gastric emptying, study of gastric acid and pepsin secretions using PEG 4,000 as marker, and upper endoscopy were performed. RESULTS: Nine out of the 20 patients had more than 10 GER per 3-hr period. Seven patients had at least one GER symptom per day. In 6 patients, pH was under 4 for more than 10% of the time. The total number of GER and the number of GER of more than 5 min duration were correlated to the body mass index (P = 0.016 and P < 0.05 respectively). The number of GER was also correlated to the android type of overweight (P < 0.03). These relationships persisted when sex, age, smoking, and obesity complications (such as diabetes) were taken into account. There was a positive correlation between the number of GER and energy and lipid intake (energy intake: 3,119 +/- 1,082 kcal/day; P < 0.003 for both). The degree of GER was positively related to basal acid output (P = 0.049), and to sham feeding-stimulated acid output (P = 0.05); it was negatively related to gastric emptying half time, but was not correlated with basal or stimulated pepsin output. A relationship was found between body mass index (BMI) and gastric emptying half time for solid (P = 0.002) and liquid phases (P = 0.001). CONCLUSION: GER seems to be common in long lasting morbid obesity. The number of refluxes increased with waist/hip ratio, BMI and energy or fat intake. GER was also increased by decreased gastric emptying rate, which was in part determined by BMI. The real prevalence of GER in morbid obeses must be determined by a large prospective study.

Adult↗