Antibiotic cements in articular prostheses: current orthopaedic concepts.

The possibilities and limits of antibiotic cements (ACs) have been assessed by many researchers. ACs are now approved by many drug agencies, including the US Food and Drug Administration (approval in 2003), with widespread use in prophylaxis and curative treatments. Laboratory experiments have achieved satisfactory antibiotic delivery without impairing the mechanical properties of ACs. Implantation in large animals (e.g. sheep) showed an antibiotic concentration in the bone cortex four times the minimal inhibitory concentration (MIC) 6 months after implantation. Human pharmacokinetics during total hip replacement (THR) show antibiotic concentrations 20 times the MIC in drainage fluids. No toxic concentrations have been detected in blood or urine, and no allergies, toxic effects, mechanical failures or selection of resistant microorganisms have been observed. Antibioprophylaxis has been assessed in prospective studies in over 1600 cases. In data from the Scandinavian arthroplasty registers, with an exhaustive follow-up of more than 240000 THRs, infection rate was reduced by ca. 50% (0.9% compared with 1.9%). In prostheses with severe infection, use of AC increases the infection control rate from 86% to 93% when using two-stage prosthetic exchanges. In moderate infection, a similar infection control rate (86%) was achieved either by two-stage exchange without local antibiotic or by one-stage exchange with AC; however, one-stage exchange achieved better functional results at lower cost and with reduced pain and hospital stay. Therefore, AC prophylaxis is widely used in countries with prostheses registers (Northern Europe), and use of ACs as treatment for infected prostheses is often considered as the gold standard in the EU and North America. However, AC is only an adjuvant treatment, and excision of infected and devascularized tissues as well as systemic antibiotic treatment managed by a multidisciplinary team remain the main factors of infection control.

Comparative study of two canal obturation techniques by image analysis and EDS microanalysis.

AIM: The aim of this in vitro study was to compare the marginal adaptation achieved by two obturation techniques (lateral condensation and Thermafil) using human teeth prepared by continuous rotation with the HERO 642(R) system. METHOD: The percentages of gaps and sealer on the root canal surface were determined by analysing the images of 12 sections per tooth. Tubule sealer penetration was assessed by backscattered scanning electron microscopy and energy dispersive spectrometry microanalysis. RESULTS: The Thermafil obturation technique resulted in virtually no gaps and very low amounts of sealer on the root surface, unlike the lateral condensation technique. Tubule sealer penetration occurred with both techniques, but was deeper, especially in the mid and apical zones, with the lateral condensation technique.

Pattern of treatment among diabetic patients in France.

Both the treatment pattern and the degree of metabolic control were estimated from a sample of 1172 French diabetic patients. The subjects were recruited from 80 medical-analysis laboratories scattered throughout the country, where they came for biologic blood sample tests. Patients had to be diagnosed as having diabetes, give consent for additional blood sampling, and fill out a short self-questionnaire. Glycosylated hemoglobin A1c (HbA1c) was centrally determined by liquid chromatography (normal range 3.5-6.3%). We found 135 patients (11.5%) who were not drug treated or treated with diet alone, 862 (73.5%) treated with oral agents, and 175 (15.0%) treated with insulin. Among the latter, 79 (6.7%) were defined as true insulin-dependent diabetes mellitus (IDDM) patients. Among patients receiving no drug or a slight dosage or oral agents, 47% were found to be in the normal range of HbA1c. On the other hand, among the patients intensively treated with oral agents or secondarily with insulin, less than half were under fair control (HbA1c less than 7.5%). These results are in agreement with previous estimates of treatment distribution derived from national drug sales data. They provide evidence regarding the particular features of diabetes in France, i.e., low prevalence of IDDM, low consumption of insulin, high consumption of oral agents. The finding of a large proportion of normal HbA1c values in non-insulin-dependent diabetic patients suggests a state of overdiagnosis linked to the use of nonspecific criteria of diagnosis in large-scale screening.

Abnormal color vision and reliable self-monitoring of blood glucose.

Color vision was assessed in 103 insulin-dependent diabetic patients using the Farnsworth-Münsell 100-Hue Test. All showed color vision impairment. Thirty-four had true dyschromatopsia while 22 suffered from tritanopia or other axial defects. We evaluated how accurately diabetic patients could monitor their own blood glucose by asking them to read a series of 30 precalibrated BM Test Glycemic Strips (Chemstrip, Boehringer, Mannheim, West Germany) without a meter. Patients with axial defects performed least well regardless of 100-Hue scores. Reading accuracy of patients with no axial defects was strongly correlated to 100-Hue scores, although patients having dyschromatopsia were consistently hesitant about their readings. Our results suggest that self-monitoring of blood glucose without a meter is indicated only after color vision has been examined by the 100-Hue Test. Self-monitoring should be voided with patients suffering from axial defects or having unsatisfactory 100-Hue scores.

Influence of simulated altitude on the performance of five blood glucose meters.

OBJECTIVE: To determine the reliability of five blood glucose meters (BGMs) at various simulated altitudes using a hypobaric chamber. RESEARCH DESIGN AND METHODS: Blood glucose levels (ranged from 1.5 to 26.3 mmol/l, according to the reference method) were measured in 18 venous blood samples by each BGM at 200, 1,000, and every 500 m up to 4,000 m in a hypobaric chamber, where temperature and humidity were held constant. RESULTS: Four BGMs underestimated and one overestimated blood glucose concentration while barometric pressure decreased. The average percent error varied in relation to simulated altitude from 0.26 +/- 4.8% (SD) at 200 m to -28.9 +/- 4.5% at 4,000 m (Glucometer 3; P < 0.05), from 28.4 +/- 5.7 to 49.3 +/- 5.9% (Accu-Chek Easy; P < 0.05), from -10.5 +/- 2.6 to 19.8 +/- 4.3% (Tracer, P < 0.05), from -5.5 +/- 2.6 to -11.2 +/- 3.0% (Reflolux; NS), and from 17.8 +/- 4.3 to 14.8 +/- 3.6% (One Touch; NS). The most accurate seemed to be the Reflolux, except for high blood glucose levels at simulated high altitudes. The One Touch II showed a good agreement, whatever the barometric pressure and the range of blood glucose concentrations. The highest underestimation was seen with the Glucometer 3. CONCLUSIONS: Except for the Accu-Chek Easy, low barometric pressure underestimated the BGM results in comparison with measurements taken at simulated low altitudes. The lack of accuracy and consistency of performance > 2,000 m should be known by diabetic patients practicing sports activities, such as trekking or skiing at high altitudes.

Mobilization of visceral adipose tissue related to the improvement in insulin sensitivity in response to physical training in NIDDM. Effects of branched-chain amino acid supplements.

OBJECTIVE: To evaluate the effects of an intense physical training program on abdominal fat distribution, glycemic control, and insulin sensitivity in patients with NIDDM and to determine whether branched-chain amino acid (BCAA) supplements influence these effects. RESEARCH DESIGN AND METHODS: Twenty-four patients (ages 45 +/- 2 [mean +/- SE] years, BMI 30.2 +/- 0.9 kg/m2, HbA1c 7.9 +/- 0.3%) were randomly assigned to four groups: training plus BCAA supplement (n = 6), training plus placebo (n = 6), sedentary plus BCAA supplement (n = 6), and sedentary plus placebo (n = 6). Physical training consisted of a supervised 45-min cycling exercise at 75% of their oxygen uptake peak (VO2 peak) two times per week and an intermittent exercise one time per week for 2 months. RESULTS: Patients who exercised increased their VO2 peak by 41% and their insulin sensitivity by 46%. Physical training significantly decreased abdominal fat evaluated by magnetic resonance imaging (umbilicus), with a greater loss of visceral adipose tissue (VAT) (48%) in comparison with the loss of subcutaneous adipose tissue (18%), but did not significantly affect body weight. The change in visceral abdominal fat was associated with the improvement in insulin sensitivity (r = 0.84, P = 0.001). BCAA supplementation had no effect on abdominal fat and glucose metabolism. CONCLUSIONS: Physical training resulted in an improvement in insulin sensitivity with concomitant loss of VAT and should be included in the treatment program for patients with NIDDM.

Androgen excess in women with acne alone compared with women with acne and/or hirsutism.

Acne is known to be one of the features of hyperandrogenism. The aim of the present work was to study women with persistent acne and without other evidence of hyperandrogenism, such as hirsutism, alopecia, or irregular menses. Among 87 female patients with acne and/or hirsutism, we defined three groups: group 1 (n = 29), patients having treatment-resistant acne without menstrual disturbance, alopecia, or hirsutism; group 2 (n = 27), patients with acne and hirsutism; and group 3 (n = 31), patients with hirsutism alone. Clinical chemistry criteria for hyperandrogenism were based on elevated values of one or more of the following parameters: plasma testosterone, delta-4-androstenedione, dehydroepiandrosterone, urinary 5 alpha-androstane 3 alpha-17 beta-diol, and 17-ketosteroids (with chromatography). Plasma and urine samples were drawn between the 18th and 25th days of the cycle. Among group 1 patients, we found 25 subjects (86%) with hyperandrogenism, according to these laboratory criteria. The etiologies were: polycystic ovary syndrome (36%), adrenal hypersecretion (40%, of which 12% showed secondary polycystic ovaries), isolated increase in 5 alpha-androstane 3 alpha-17 beta-diol (20%), and hyperandrogenism without diagnosis (4%). The parameters were found to be more elevated in these patients than in a control group of 30 normal volunteer women. In groups 2 and 3, the findings were essentially the same as in group 1, except for increased levels of testosterone and the testosterone/SHBG ratio. Furthermore, it was evident that persistent acne may be an isolated sign of hyperandrogenism.

Adrenocortical 11 beta-hydroxylation defect in adult women with postmenarchial onset of symptoms.

Four cases in adults of a deficiency in the 11 beta-hydroxylation of corticosteroids were investigated by both basal and dynamic biological studies. Symptoms varied from patient to patient; hirsutism, menstrual disturbance, acne, deepening of the voice, and arterial hypertension appeared post puberty. Basal testing demonstrated elevated levels of plasma androgens. These include delta 4-androstenedione (patients, 3.80-6.43 ng/ml; normal, 1.33 +/- 0.33 ng/ml), urinary 17-ketosteroids (patients, 11.8-16.7 mg/24 h; normal, 5-10 mg/24 h), and urinary dehydroepiandrosterone. The basal tests were often insufficient to show the accumulation of the precursors (especially 17-hydroxyprogesterone) which are often given as evidence for an increase in ACTH stimulation. In studying the levels of the mineralocorticoids, there was shown to be an increased basal level of tetrahydrodeoxycorticosterone (patients, 142-317 microgram/24 h; normal, 60-80 microgram/24 h) which was raised by ACTH stimulation. These results, therefore, confirm the characteristic partial enzyme defect and give evidence for the heterogeneity of this syndrome. Based on the above observations, we believe it is appropriate to rename this condition adult adrenocortical 11 beta-hydroxylation defect rather than late-onset congenital adrenal hyperplasia.

Evaluation of abdominal fat distribution in noninsulin-dependent diabetes mellitus: relationship to insulin resistance.

Accumulation of visceral adipose tissue is associated with metabolic complications such as noninsulin-dependent diabetes mellitus. The aim of this study was to evaluate the effect of abdominal adipose tissue on insulin sensitivity in subjects with noninsulin-dependent diabetes mellitus (NIDDM). Areas of abdominal fat were calculated from axial magnetic resonance images obtained at the level of the umbilicus in 21 men with NIDDM [age, 45.6 +/- 8.3 (+/-SD) yr; body mass index, 29.3 +/- 4.5 kg/m(-2); total body fat (skinfold thickness), 26.8 +/- 5.4%; waist to hip ratio, 0.97 +/- 0.07; duration of diabetes, 59 +/- 47 months; hemoglobin A1c, 8.1 +/- 1.5%]. Insulin sensitivity was evaluated by an insulin tolerance test. The areas of deep abdominal fat and sc abdominal fat were, respectively, 135.3 +/- 55.1 and 211.8 +/- 99.1 cm2. The blood glucose disappearance rate was 2.11 +/- 0.87%/min and was negatively related to deep abdominal fat (r = 0.72; P = 0.0025). In contrast, areas of sc abdominal fat, total body fat, body mass index, and waist to hip ratio were not related to the blood glucose disappearance rate. Plasma triglyceride concentrations averaged 1.8 +/- 0.8 mmol/L and were positively related to deep abdominal fat (r = 0.69; P = 0.0018). We conclude that insulin sensitivity is strongly related to visceral adipose tissue accumulation in NIDDM.

Characterisation and quantification of angiogenesis in beta-tricalcium phosphate implants by immunohistochemistry and transmission electron microscopy.

The aim of this study is the histological characterisation of angiogenesis in a macroporous biomaterial with quantification techniques used in oncology. Porous tricalcium phosphate implants were seated in the tibias of 12 rabbits. This work allows (1) morphological study with photonic microscopy, transmission electron microscopic and immunohistochemistry labelling for (2) quantification of vascularisation using anti-CD31 monoclonal antibody (3) quantification of proliferation using anti-PCNA polyclonal antibody (4) study of two angiogenic growth factors: VEGF and FGF-2. Quantification of angiogenesis revealed an outbreak kinetic with early vascular growth in first several days and a second growth phase after 4 weeks. This study reveals in macropores many isolated cells without adjacent vascular lumen, with endothelial phenotype. Expression of angiogenic growth factors reveals that all endothelial cells were VEGF-negative throughout the test period. FGF-2 expression by endothelial cells began 2 weeks post-implantation. Osteoblasts strongly expressed two markers throughout the test period. Furthermore, the procedure described here can be used to compare angiogenesis in different biomaterials or in the same biomaterial with the influence of macroporosities.

Management of newly diagnosed non-insulin-dependent diabetes mellitus in the primary care setting: effects of 2 years of gliclazide treatment--the Diadem Study.

Five thousand five hundred seventy-two newly diagnosed non-insulin-dependent diabetes mellitus (NIDDM) patients (3,225 men and 2,347 women; mean age, 58.5 years) were recruited through the General Practitioners (GPs) network in France. All had persistent hyperglycemia after a preliminary 3-month period with dietary and life-style modification. Gliclazide (80 to 320 mg/d) was then prescribed as diabetic pharmacotherapy for 2 years. Additional therapy for hypertension and dyslipidemia was started if necessary. The aim of the study was mainly to determine the feasibility of a GP-directed protocol for the monitoring and treatment of newly diagnosed NIDDM patients, and to assess the effectiveness of diabetic therapy in this cohort. Diabetes was diagnosed in 78% of the cohort during routine screening. Among the women, 6.5% had a history of gestational diabetes. Eighteen percent of the patients had a parental history of diabetes, and the dominant maternal role in the genesis of NIDDM was confirmed. High blood pressure (Joint National Committee V criteria) was found at inclusion in 38.8% of the whole cohort. Hyperlipidemia was known in 44.6%. A history of stroke was present in 1.6% of the patients, and coronary heart disease (CHD) in 6.3%. These data support the relationship between the atherogenic state and development of NIDDM. Microalbuminuria defined as urinary albumin excretion (UAE) of at least 20 mg/L was found in 29.6% of the patients, and retinopathy in 9.8%. Among the included patients, 23% did not complete the study and were excluded from the efficacy analysis. Of these, 14% (808 patients) had only baseline evaluation data and 9% (499 patients) withdrew later. Comparison of mean baseline and final results in study completers uncovered a significant improvement in fasting blood glucose ([FBG] 182 +/- 48 v 137 +/- 40 mg/dL), post prandial blood glucose ([PPBG] 209 +/- 68 v 162 +/- 52 mg/dL), and hemoglobin A1c ([HbA1c] 8.7% +/- 2.5% v 7.3% +/- 2.0%). A slight improvement in total cholesterol (228 +/- 44 v 222 +/- 41 mg/dL), body mass index ([BMI] 28.5 +/- 4.7 v 27.9 +/- 4.5 kg/m2), and waist to hip ratio (0.99 +/- 0.1 v 0.98 +/- 0.1) was observed. There was a decrease in the percentage of patients with high blood pressure (38.5% v 30.7%). A mild increase in the prevalence of retinopathy (10.2% v 11.8%) was noted during the study, while the incidence of microalbuminuria remained unchanged (30.2% v 29.5%). In conclusion, the data indicate that the GPs involved in this study were able to successfully monitor and manage NIDDM patients in accordance with a standardized protocol. Gliclazide appeared to be an effective and well-tolerated treatment. The high prevalence of chronic diabetic complications at diagnosis emphasizes the delay encountered in reaching the diagnosis of NIDDM and the problems associated with this delay. In addition to the classic risk factors for NIDDM exhibited in this patient cohort, we have identified CHD and a maternal genetic component as further potential predicting factors.

Changes in breath 13CO2/12CO2 during exercise of different intensities.

The measurement of breath 13CO2/12CO2 is commonly used during exercise to evaluate the oxidation rate of exogenous carbohydrates enriched in 13C. The aim of this study was to investigate whether exercise itself affects the 13C/12C ratio in expired air CO2 in relation to exercise intensity. The relative abundance of 13C and 12C in expired air CO2 was determined by isotoperatio mass spectrometry and expressed as delta 13C (in %o) by using Craig's formula and calibrated standards. Five healthy young men exercised on a treadmill after an overnight fast during > or = 105 min on four occasions and in a randomized order. Work rates were performed at approximately 30, 45, 60, and 75% of their maximal O2 uptake (VO2max). Delta 13C in expired air CO2 and respiratory exchange ratio (RER) were determined every 15 or 30 min during exercise. At 30 and 45% VO2max, a slight and not statistically significant increase in delta 13C was observed at 30 min. In contrast, at 60 75% VO2max, the rise was statistically significant and averaged 0.83 and 0.99%o, respectively. Average delta 13C (between 0 and 105 min) progressively increased with the intensity of exercise. Individual values of delta 13C and RER were positively correlated (r = 0.653, P = 0.002) as were values of delta 13C and endogenous carbohydrates utilized (r = 0.752, P < 0.001). Factitious or "pseudooxidation" of a 13C-enriched exogenous glucose load (indeed noningested) was calculated from the changes in expired air delta 13C. Over the whole period of exercise it was not statistically significant at 30 and 40% VO2max. However, over the first 60 min of exercise, such pseudooxidation of exogenous glucose was significant at 30 and 45% VO2max. In conclusion, by modifying the mix of endogenous substrates oxidized, exercise at 60% VO2max and above significantly increases the 13C/12C ratio in expired air CO2. At these intensities, this could lead to overestimation of the oxidation of 13C-labeled substrates given orally. At lower intensities of exercise, such overestimation is much smaller an affects mainly the values recorded during the initial part of the exercise bout.

17 beta-Estradiol: oral or parenteral administration in hyperandrogenic women? Metabolic tolerance in association with cyproterone acetate.

OBJECTIVE: To compare the metabolic effects of two different administration routes of estrogen associated with cyproterone acetate (CPA) in young women. DESIGN: Randomized and prospective study. SETTING: University medical and research center. PATIENTS: Sixty-five premenopausal young women with clinical hyperandrogenism. INTERVENTIONS: A high dose of CPA was administered, associated with either transdermal (group T) or oral (group O) 17 beta-E2. MAIN OUTCOME MEASURES: Glucose tolerance, plasma lipid level, coagulation and fibrinolysis parameters, and angiotensinogen, before and at 6 and 12 months during treatment. RESULTS: At 12 months, fasting blood glucose and basal insulin levels were significantly lower in group O than in group T. The increase in angiotensinogen was greater in group O, however, without modification in arterial blood pressure. No significant difference between the two groups was observed in lipids, coagulation, and fibrinolysis. CONCLUSION: Natural estrogens associated with CPA have no patent deleterious metabolic effect. However, the choice of oral estrogen administration seems to be better among patients with disorders such as hyperandrogenism or obesity with potential hyperinsulinism.

[Insulin sensitivity and hepatic glucose production: nycthemeral variations]. / Sensibilité à l'insuline et production hépatique de glucose: variations nycthémérales.

Glucose tolerance is subject to circadian variations and has been found to be better in the morning or afternoon. An increase in plasma glucose and insulin concentrations has recently been observed between 5 and 9 a.m. These physiological changes correspond to an increase in insulin requirements in patients with insulin-dependent diabetes mellitus (the "dawn phenomenon"). In patients with non-insulin-dependent diabetes mellitus, the circadian rhythm of insulin secretion is suppressed. Studies of insulin sensitivity during a hyperinsulinaemic hyperglycaemic clamp (a supraphysiological experimental condition) indicated that: i) insulin-induced glucose utilization is decreased in the morning according to a circadian rhythm; ii) this change results from an increase in hepatic glucose production but not from a decrease in glucose uptake; and iii) a circadian rhythm is also observed for plasma free fatty acids and cortisol concentrations, which could account in part for the circadian changes in insulin sensitivity. Recognition of these circadian changes has implications for the treatment of non-insulin-dependent diabetes mellitus.

Effects of a single bout of exercise and exercise training on steroid levels in middle-aged type 2 diabetic men: relationship to abdominal adipose tissue distribution and metabolic status.

Lower androgen levels have been suggested to be associated with type 2 diabetes and central obesity and are probably involved into the development of atherosclerosis. The present study investigates the effect of acute and chronic exercise on Dehydroepiandrosterone (DHEA) levels in relation to abdominal fat distribution and metabolic status in type 2 diabetes. Twenty weight-stable, middle-aged males with type 2 diabetes were enrolled in the study and participated in a submaximal (VO(2) peak) and moderate (50% VO(2) peak) exercise bout. The subjects were randomly assigned either to a trained or a control group, respectively. Physical training consisted of an 8 week program of aerobic exercise (75% VO(2) peak, 45 min), twice a week and intermittent exercise, once a week, on a bicycle ergometer. Acute exercise significantly increased DHEA and Testosterone (T) levels. Physical training increased VO(2) peak (42%, p <0.001), insulin sensitivity index (K(ITT) ) (57.5%, p <0.02), and basal DHEA levels (36%, p <0.05), and decreased HbA1c (29%, p <0.001), visceral adipose tissue (VAT) (44%, p <0.01) and subcutaneous adipose tissue (SAT) levels (18%, p <0.01). Body weight, BMI and insulin, T levels were not modified. Changes in DHEA levels were not correlated with changes in insulin sensitivity and abdominal fat distribution. In conclusion, exercise training favourably affects DHEA levels independently of improvements of metabolic status and abdominal fat distribution in patients with type 2 diabetes.

Multicenter randomized evaluation of a nutritional education software in obese patients.

OBJECTIVE: To study the efficacy of the nutritional education software, Nutri-Expert, in the management of obese adult patients. MATERIAL AND METHODS: Two groups of obese patients were followed up over one year in a randomized study: the first group received close traditional management (seven nutritional visits over the year, with physicians and dietitians conjointly) and the second one also used at home by Minitel the Nutri-Expert system. 557 patients were enrolled in the study by 16 French centers of diabetology and nutrition. Body mass index (BMI), tests of dietetic knowledge, dietary records and centralized biological measurements were assessed at inclusion, 6 and 12 months. 341 patients were evaluable at the end of the year. RESULTS: The group using Nutri-Expert scored significantly better in the tests of dietetic knowledge than the control group. For all patients, nutritional education led to a significant improvement in BMI, dietary records and biological measurements, without significant difference between the two groups. Five years after the end of the study, the weight of 148 patients was recorded; mean BMI was significantly lower than the initial value but there was no significant difference between the two groups. CONCLUSION: In the management of obese patients, Nutri-Expert system has a role to play in reinforcing nutritional knowledge; if regular follow-up is not possible, or if a large series of obese patients is to be treated, Nutri-Expert could partly replace traditional management, for example between visits.

Low prevalence of long-term complications in non-insulin-dependent diabetes mellitus in France: a multicenter study. CODIAB-INSERM-ZENECA Pharma Study Group.

The aim of this study was to assess the prevalence of long-term complications in a large sample of French NIDDM patients. Therefore, 427 NIDDM patients 35-74 years old were recruited in ten centers. Standardized clinical criteria and central reading for retinal and electrocardiographic changes were used to assess the presence of complications. The prevalence rates of complications were 29.7% and 3.3% for background and proliferative retinopathy; 21.8%, 6.1%, and 2.8% for microalbuminuria, proteinuria, and renal insufficiency; 19.9 and 11.7% for asymptomatic and symptomatic pheripheral neuropathy; 8.2% for orthostatic hypotension; 10.1% and 8.4% for angina pectoris and myocardial infarction; and 13.1% and 6.3% for mild and moderate to severe peripheral vascular disease, respectively. In conclusion, prevalence rates in this study were lower than in most studies from other countries.

Severe acne due to chronic amineptine overdose.

We report six women with severe acne lesions associated with taking amineptine, a tricyclic antidepressant. The lesions appeared after self-administration of high doses of the drug over long periods of time. They mainly occurred on the face, back, and thorax, but were also found on the extremities and in the perineal region. In five of the six cases, severity of cutaneous lesions appeared to be correlated with degree of overdose. The sixth patient never admitted having taken amineptine. Most of the patients had been unsuccessfully treated with isotretinoin for 18 months. In all six cases, chromatography of urinary 17-ketosteroids showed abnormal peaks and retention times which were different from those usually found for known steroids. In addition, the areas under these peaks were found to be a function of the degree of intoxication and of the clinical severity of the lesions. Mass spectrometry was used to qualitatively study urinary amineptine metabolites, disclosing compounds normally found only in trace amounts, as well as certain others heretofore not described in man. In two of the three patients who stopped taking amineptine, cutaneous lesions subsequently diminished, totally disappearing in the least severe case.

The relationship between tooth vibratory sensation and periodontal disease.

Forty subjects both with and without periodontal disease were studied. Tooth proprioception was tested in regard to vibratory stimuli and the sensory perception thresholds were measured. A link was found between the quantitative diminution of the periodontal ligament and alveolar bone and the perception thresholds relative to vibratory stimuli. These thresholds are elevated in subjects with periodontal disease and are dependent on the region of the dental arch to which the stimulus is applied. Modification of these afferent sensory impulses leads to a change in the occlusal stroke pattern and possible exacerbation of the initial insult.

Impact of torsional and bending inertia on root canal instruments.

The laws of applied mechanics can be used to analyze and predict the behavior of mechanical parts subjected to strain and distortion, such as endodontic instruments. Simple mathematical formulas can be used to represent the impact of torsional and bending inertias on stresses in endodontic instruments being used in root canals. The boundary integral method was applied to two theoretical models with the same diameters but different cross-sections to evaluate quantitatively and qualitatively the stresses produced in orthogonal cross-sections. The results confirmed the mathematical deduction concerning the impact of torsional and bending stresses. The results indicate that clinical protocols based on the torsional and bending properties of endodontic instruments must be strictly followed, and endodontic instrument manufacturers must adopt standardized criteria for describing these properties.