Estimation of blood-flow quality by statistical analysis or an ultrasonic Doppler signal: application to the study of perturbations caused by a vascular stenosis.

The noninvasive detection of pathological stenoses by Doppler ultrasound velocimetry is based on the appearance of modifications in velocity waveform or of a local increase in velocity. Nevertheless, these methods suffer from a lack of sensitivity. An extension of ultrasonic velocimetry including a statistical treatment of the Doppler signals affords a quantitative approach to the flow quality and seems to be able to improve the diagnosis of vascular obliterans. Accordingly a perturbation index can be computed on a microprocessor as the relative standard deviation of the zero-crossings histogram of the Doppler signal. A theoretical and experimental approach has been attempted to validate this method. Moreover, this index has been tested in vitro on calibrated flows. The in vivo experiments, performed on the abdominal aorta of the dog with artificial stenoses (0 to 50% in diameter) show a significant increase in the index value downstream from the stenosis. The relative increase of the index is greater than that of velocities for the same degree of obstruction. At the moment, it is possible to detect stenoses of 20% and above. It should be noted that changes in the perturbation index can be observed on a large part of the arterial segment, in relation with the severity of teh stenosis. Taking into account the increase in the index value and the length of the disturbed zone downstream of the stenosis, an estimation of the severity itself can be attempted. Clinical applications are in progress pointing out the diagnostic and prognostic abilities of the index method. The index perturbation method adds to velocity measurement the possibility of blood flow stability estimation. It appears useful for the localisation of stenoses, offers the possibility of quantifying their severity and could help the prognosis of their development.

Intra-SA-nodal pacemaker shift: indirect evaluation in the open chest dog.

Thirteen open chest dogs with normal sinus node function were studied by premature stimulations with a constant relative prematurity--50% of the preceding sinus cycle length. These premature beats were induced in the lower part of the crista terminalis of the right atrium and to the roof of the left atrium. Significant linear correlations were found between the return cycle (A2A3) and the spontaneous cycle (A1A1) lengths, with a slope of +0.75 in the right atrium, +1.36 in the left atrium. The evaluation of sinus node function is disturbed by pacemaker shifts, both spontaneous and induced. Sinus node organisation may be assessed by stimulating standardised sites, by measuring intra-atrial conduction time, and by comparing A2A3 with A1A1 at constant relative prematurity during significant variations in A1A1 obtained with changes in vago-sympathetic tone.

Intracellular and extracellular recordings of sinus node activity: comparison with estimated sinoatrial conduction times during pacemaker shifts in rabbit heart.

Sinoatrial conduction times, estimated by premature atrial stimulation, were compared with direct measurement of the sinoatrial conduction time in 15 isolated rabbit sinus node preparations before and after intrasinusal pacemaker shifts induced by cooling. Transmembrane potentials and surface electrograms were recorded from the sinus node and crista terminalis. Extracellular sinus node activity was recorded in five preparations. Mapping was performed at 38 degrees C and 35 degrees C to determine the site of the dominant pacemaker. The sinus cycle was significantly longer at 35 degrees C (319.4 ms vs 258.1 ms). Intracellular measured conduction time was significantly shorter (63.8 ms vs 70.4 ms) because of caudal shift of the dominant pacemaker. Estimated sinoatrial conduction time was significantly longer (110.3 ms vs 85.4 ms) owing to the depression of automaticity by the extrastimulus. Extracellular measured conduction time did not differ significantly from intracellular measured conduction time. These results suggest that intrasinusal pacemaker shift may explain inaccuracies in indirect estimations of sinoatrial conduction time by atrial pacing techniques. Extracellular recordings appear to be a better method of evaluating sinoatrial conduction times.

The prevalence of diabetes mellitus in the adult population of Guadeloupe as estimated by history or fasting hyperglycemia.

A study was conducted between January 1984 and March 1985 to determine the prevalence of diabetes in the adult population of Guadeloupe (18 years of age and over). A two-step sampling frame, using a sampling fraction of 0.46%, where the primary units were composed of districts and where sub-units were households, was used. The household refusal rate was 22%. Subjects were classified as 'diabetic' when they were either already known or when their fasting plasma glucose was above 8.0 mmol/l. The total age and sex standardized prevalence of diabetes among the adult population of Guadeloupe can be estimated at 6.6%. The high prevalence rate appears to be related to obesity (strongly in women), a genetic susceptibility (22.5% of age standardized prevalence among subjects of Asian Indian origin for both sexes), and, possibly, in men of African origin only, to a maternal history of diabetes.

[Incidence, diagnosis, treatment and prognosis of cancer of the pancreas: development in Côte-d'Or from 1976 to 1985]. / Incidence, diagnostic, traitement et pronostic du cancer du pancréas: évolution en Côte-d'Or de 1976 à 1985.

The aim of this study was to analyze the epidemiological aspects of pancreatic cancers and their time trends in the Côte-d'Or population between 1976 and 1985. Over a period of ten years, 444 cases were diagnosed. The incidence rates standardized according to the world reference population were 8.2/100,000 in males and 3.8/100,000 in females. The Côte-d'Or is an intermediate risk area for pancreatic cancer. This cancer was slightly more common in urban than in rural areas (NS). The initially urban predominance of pancreatic cancer in males was no longer present 10 years later. Between 1976 and 1985, incidence of pancreatic cancer decreased by a mean of 4.7% per year in males (NS) and 0.5% per year in females (NS). A high proportion of the cancers (73.9%) were located in the head of the pancreas; among histologically confirmed cases, 69.7% were adenocarcinomas. Criteria for diagnosis evolved throughout the 10 years. The rate of histological confirmation increased annually by a mean of 3.0% (P less than 0.001). The relative importance among diagnostic procedures of direct biliary and pancreatic examinations decreased (P less than 0.05) whereas that of ultrasonography and radioscan increased (P less than 0.001). The overall surgical rate was 64.4% and the rate of curative surgery was 4.4%. The operability rate increased annually by a mean of 2.0% (NS). The overall survival rate was 13.2% after 1 year, 4.5% after 3 years and 3.2% after 5 years. Prognosis depended neither on age nor on sex or cancer location. The 5-year survival rate was 38.5% in the limited group of patients (n = 13) who underwent surgery for cure, and 0.0% in patients with palliative treatment. These data emphasize the severity of pancreatic cancers and the absence of any therapeutical improvement between 1976 and 1985 in spite of the evolution in diagnostic procedures.

[Measured and estimated sinoatrial conduction during variations in rhythm. Microelectrode study of the isolated rabbit atrium]. / Conduction sino-auriculaire mesurée et estimée lors des variations du rythme. Etude par micro-électrodes sur oreillette isolée de lapin.

Strips of isolated atrium were obtained from 10 rabbits to study the validity of indirect methods of estimating sinoatrial conduction time during variations of the sinus rhythm. Direct recordings of the trans-membrane action potential of the sinus node were made. Mapping of the sinus region was undertaken to determine the site of the dominant pacemaker. A quadripolar surface electrode was positioned on the lower part of the crista terminalis for stimulation and recording of the atrial potential. This enabled a comparison to be made between the indirect estimated and the directly measured conduction times. An intrasinusal shift of the dominant pacemaker was obtained by cooling from 38 degrees C to 35 degrees C. This shift occurs progressively in the cranino-candal direction. The estimated and measured conduction times were compared under basal conditions and after cooling. The sinus cycle was significantly longer (p less than 0.001) at 35 degrees C (318 +/- 68 ms) than at 38 degrees C (255 +/- 48 ms). The mean measured anterograde conduction time also decreased from 36 to 31 ms (p less than 0.01) and the mean measured retrograde conduction time also decreased from 39 to 33 ms (p less than 0.02); the total conduction time decreased from 75 to 64 ms (p less than 0.001). The results of the total estimated conduction times were discordant. The associated effects of stimulation and cooling can cause conduction defects and an overestimation of the conduction time.(ABSTRACT TRUNCATED AT 250 WORDS)

[Diagnostic modalities and treatment of cancer of the pancreas. Evolution in the population in the department of Côte d'Or from 1976 to 1988]. / Les modalités diagnostiques et le traitement du cancer du pancréas. Evolution dans la population du département de la Côte-d'Or de 1976 à 1988.

There is no study establishing time trends for the diagnostic and therapeutic approaches to pancreatic cancer based on population data. The data of the Registry of Digestive Tumors of Côte-d'Or (France) were used to this end in 544 cancers diagnosed between 1976 and 1988. The proportion of the histologically confirmed cases increased annually by 13.4% (P < 0.001). This was mainly due to progress in percutaneous biopsy (+25.7% per year between 1983 and 1988, P < 0.001). As regards the diagnosis, ultrasonography was used more frequently (+21.9% per year, P < 0.001) as well as CT scan since its introduction in 1983 (+19.6% per year, P < 0.001). Pancreatic cancer was diagnosed by sonography in 16.7% of the cases in 1976 and 70.6% in 1988 (mean annual variation: +5.7%, P < 0.001). The proportions for CT scan were 12.8% in 1983 and 23.5% in 1988 (mean annual variation: +3.5%, NS). There was no significant change in the use of retrograde cholangiopancreatography over time. Other diagnosis criteria were less frequently used: laparoscopy was no longer used after 1983 and intraoperative diagnosis was made less frequently (-2.5% per year, P < 0.001). Endoscopy or radiographic data were rarely used as a diagnosis criterion. These changes in approaches to the diagnosis of pancreatic cancer were not accompanied by any progress in diagnosis stage, therapeutic approach or survival suggesting that when clinical symptoms become evident, pancreatic cancer is already advanced. Therapeutic advances, early diagnosis in patient at risk or identification or reasons for pancreatic cancer are the only means of progress in this problem.

[Electromagnetic residential fields and childhood cancers: state of epidemiological research]. / Champs magnétiques résidentiels et cancers de l'enfant: l'état de la recherche en épidémiologie.

Thirteen epidemiological studies of the relations between electromagnetic fields and childhood cancers have been published. Eleven have shown some associations between the presumed intensity of exposure to residential magnetic fields and the childhood cancers incidence, either for all cancers or for the 3 most frequent types (leukaemias, brain tumours and lymphomas). These associations are not often significant because of the weak statistical power of these studies in relation with both the low incidence of cancers in childhood, and specially of each particular type, and the little number of subjects considered to be exposed at a high level exposure for residential magnetic fields. All these studies fall in with the same difficulties, particularly for identification and assessment of the exposure to magnetic fields and for the manner to take into account all the potential confounders. So even significant associations do not imply their causality, all the more as the carcinogenicity of extremely low frequency electromagnetic fields, although biologically conceivable, has never been experimentally proven. Today it is impossible to claim or invalidate the influence of residential magnetic fields in the genesis of childhood cancer. Setting up of new epidemiological studies based on large number of cases issued from population based registries and conducted with a best defined methodology seems to be highly desirable.

Arterial hypertension in the adult population of Guadeloupe, and associated factors in subjects of African origin.

This study was designed to estimate the prevalence of hypertension in Guadeloupe, the French West Indies, and to evaluate the risk factors associated with hypertension in the largest ethnic group, that of African origin. Households were randomly selected using a two-stage systematic sample of districts and then of houses; all adults aged 18 years in the household were included. In total, 1043 men and women were studied. Blood pressure, plasma glucose concentrations and gamma-glutamyl transferase activity were measured, hypertensive treatment and lifestyle factors recorded. The prevalence of hypertension, age-standardized to the Guadeloupe population was 21% and 26% in men and women of African origin, 28% and 22% in those of Indian-origin and 18% and 16% for other origins. The vast majority of subjects were unaware of their hypertension (90% of men, 74% of women). After adjustment for age, factors associated with high blood pressure in the 826 adults of African origin were: obesity, hyperglycemia, low educational level and family history of hypertension and of stroke. Additional factors in women were alcohol consumption, gamma-glutamyl transferase activity, physical inactivity, occupational category and a retired status, even after adjustment for age. Measures must be taken to diagnose hypertension early, particularly in individuals of African and Indian origin. An effective education program is needed, with an emphasis on life-style factors associated with obesity: diet and physical activity.

[Indicators of glycated proteins in the diagnosis of diabetes. Use in populations with a high prevalence of hemoglobinopathies]. / Marqueurs de la glycation des protéines dans le dépistage du diabéte. Application aux populations à forte prévalence d'hémoglobinopathies.

The authors compare the relative validity of HbA1c and fructosamine as indices of long-term blood glucose levels in population with a common occurrence of haemoglobinopathies. HbA1c levels in patients with haemoglobinopathies do not reflect the glucidic status of patients when compared to HbA1c levels in reference population. Validity of the fructosamine assay allows its potential use as a mass screening test for diabetes in these populations (USA, Africa, Caribbean...).

Diabetes mellitus and public health in Guadeloupe.

Diabetes mellitus is now among the ten leading causes of death in the Caribbean. Studies of the prevalence of dysglycaemic disorders and risk factors for diabetes are necessary in order to design and implement tailored prevention programmes. The present study is of a representative sample of the adult population in Guadeloupe. The estimated prevalence of diabetes is 5.8% in adults, and that of impaired glucose tolerance is 7.4%. The percentage of insulin-treated patients is low, 14% of diabetics. The principal risk factors of diabetes, as classically recognised, are shown to operate. At the individual level, the presence of a diabetic parent is a greater relative risk factor than obesity. However, considering the large percentage of persons who are obese, obesity seems to be the principal factor at which a primary prevention programme at the community level should be aimed, in order to limit the incidence of hyperglycaemic states.

An apparently paradoxical action of aging: decrease of acute hypoxic mortality in male aged rats.

Mortality of SPF male rats due to hypoxic challenge is less in old than in young rats. This apparent antinomy may be related to a decrease in oxygen consumption because of the relation of volume-surface and, in very old rats (590-700 days old), to a selection process wherby only the hypoxiaresistant rats reach old age.

[Influence of recent modification of behavioral relationships of male and female OF1 mice on resistance to nitrogen or carbon monoxide hypoxia]. / Influence d'une modification récente de relations comportementales sur la résistance de souris mâles et femelles OF1 à une hypoxie par inhalation d'azote ou d'oxyde de carbone

A decrease of resistance to hypoxia is obtained in OF1 mice, 24 hours after an hyperactivity resulting from a grouping by 13 of male or female mice previously isolated. Besides, this decrease is statistically significant in an acute nitrogen hypoxia but not in an acute carbon monoxide poisoning. In both hypoxias, in mice of same age the males are less resistant than females.

[Demonstration in Japanese quails of genetic differences in survival from hypoxia]. / Mise en évidence, chez la Caille japonaise, de différences génétiques lors de la survie à l'hypoxie

164 quails (Coturnix coturnix japonica; 94 males and 40 females), 27-55 days old and belonging to 9 families, each family being issued from a different couple of parents, were submitted to an acute nitrogen hypoxia which resulted in an overall mortality of 43.29%. The fact that a high statistically significant (p less than 0,001) heterogeneity was pointed out in these different families supports the existence of a genetic component of resistance towards hypoxia.

Alcohol consumption in Guadeloupe.

This study bears upon the patterns of alcohol consumption in Guadeloupe (French West Indies), and has been carried out over a representative sample of adults. Each subject was questioned about his or her consumption of alcoholic drinks and a blood sample taken to measure the biological indicators of chronic alcohol consumption. The resulting mean consumption has permitted Guadeloupeans to be classed among the world's foremost consumers of alcohol. For almost half of the adult population, this consumption takes place on a daily basis and therefore constitutes part of everyday life. The patterns of alcohol consumption are linked to sex, age, level of education, employment and socio-professional categories. The heavy-drinking man tends to be elderly, has a low level of education and is an agricultural worker; his consumption is based on rum. The woman is middle-aged and not working; her consumption is based on wine. These stated characteristics permit the setting up of tailored prevention programs.

Residential magnetic field measurements in France: comparison of indoor and outdoor measurements.

Residential magnetic field (MF) measurements were performed for the first time in a representative sample of French dwellings. Exposure levels were assessed by two methods: indoor and outdoor measurements. Linear and logistic regression models were used to determine factors associated with the time-weighted average (TWA) home MF. TWA magnetic field magnitudes were approximately log-normally distributed with geometric means under 0.010 microT for both indoor and outdoor measurements. Only 5% of the dwellings presented indoor MF levels greater than 0.120 microT (1.2 mG). Both indoor and outdoor MF variations were explained by three factors: wiring configuration, the dwelling's location (i.e., urban or rural), and housing characteristics (individual houses or apartment building). The reliability of outdoor spot measurements with 30-min bedroom recordings was assessed by an intraclass correlation coefficient. The measurements were accurate in rural areas and small towns. In urban centers, local MF variations spoil the outdoor measurement's reliability. If indoor measurements are taken as the reference method, the use of outdoor instead of indoor measurement leads to an important decrease in statistical power. Further assessment of MF near high power transmission lines is necessary to evaluate the usefulness of outdoor spot recordings near such lines. The urban MF environment also has to be explored to identify extraneous sources.