Biomass allocation and plant morphology explain the difference in shrub species abundance in a temperate forest

In forested ecosystems, shrubs must succeed in persisting in low-light environments, while simultaneously having the ability to rapidly expand and occupy newly created canopy openings, yet little is known about the traits that make this possible. We hypothesize that shrub species that are abundant in the understory exhibit a specific set of functional traits that define their ability to persist during unfavorable periods and to rapidly exploit newly created habitats. We tested this by comparing field-measured functional traits such as biomass allocation, leaf display, crown morphology, and leaf traits, across individual size classes and two gap-forest environments of five shrub species. We observed significant differences in traits between species, size classes, and gap-forest environments. These differences were primarily related to biomass allocation traits, followed by leaf display, crown morphology, and leaf traits. Abundant shrubs like mountain maple (Acer spicatum) and hazelnut (Corylus cornuta) invested significantly more biomass in roots, had a larger total leaf area, and displayed leaves in a more efficient manner to intercept light. The high investment in root biomass can be interpreted as shrubs exploiting the persistence and colonization strategy through resprouting. Permanent sub-canopy status likely explains the importance of efficient leaf display, wherein abundant shrubs had a large leaf area with minimal support structures.

Cross-scale integration of knowledge for predicting species ranges: a metamodeling framework

AIM

Current interest in forecasting changes to species ranges have resulted in a multitude of approaches to species distribution models (SDMs). However, most approaches include only a small subset of the available information, and many ignore smaller-scale processes such as growth, fecundity, and dispersal. Furthermore, different approaches often produce divergent predictions with no simple method to reconcile them. Here, we present a flexible framework for integrating models at multiple scales using hierarchical Bayesian methods.

LOCATION

Eastern North America (as an example).

METHODS

Our framework builds a metamodel that is constrained by the results of multiple sub-models and provides probabilistic estimates of species presence. We applied our approach to a simulated dataset to demonstrate the integration of a correlative SDM with a theoretical model. In a second example, we built an integrated model combining the results of a physiological model with presence-absence data for sugar maple (Acer saccharum), an abundant tree native to eastern North America.

RESULTS

For both examples, the integrated models successfully included information from all data sources and substantially improved the characterization of uncertainty. For the second example, the integrated model outperformed the source models with respect to uncertainty when modelling the present range of the species. When projecting into the future, the model provided a consensus view of two models that differed substantially in their predictions. Uncertainty was reduced where the models agreed and was greater where they diverged, providing a more realistic view of the state of knowledge than either source model.

MAIN CONCLUSIONS

We conclude by discussing the potential applications of our method and its accessibility to applied ecologists. In ideal cases, our framework can be easily implemented using off-the-shelf software. The framework has wide potential for use in species distribution modelling and can drive better integration of multi-source and multi-scale data into ecological decision-making.

Multi-parametric MRI of rectal cancer - do quantitative functional MR measurements correlate with radiologic and pathologic tumor stages?

PURPOSE

The purpose of this study is two-fold. First, to evaluate, whether functional rectal MRI techniques can be analyzed in a reproducible manner by different readers and second, to assess whether different clinical and pathologic T and N stages can be differentiated by functional MRI measurements.

MATERIALS AND METHODS

54 patients (38 men, 16 female; mean age 63.2 ± 12.2 years) with pathologically proven rectal cancer were included in this retrospective IRB-approved study. All patients were referred for a multi-parametric MRI protocol on a 3 Tesla MR-system, consisting of a high-resolution, axial T2 TSE sequence, DWI and perfusion imaging (plasma flow -s PFTumor) prior to any treatment. Two experienced radiologists evaluated the MRI measurements, blinded to clinical data and outcome. Inter-reader correlation and the association of functional MRI parameters with c- and p-staging were analyzed.

RESULTS

The inter-reader correlation for lymph node (ρ 0.76-0.94; p<0.0002) and primary tumor (ρ 0.78-0.92; p<0.0001) apparent diffusion coefficient and plasma flow (PF) values was good to very good. PFTumor values decreased with cT stage with significant differences identified between cT2 and cT3 tumors (229 versus 107.6 ml/100ml/min; p=0.05). ADCTumor values did not differ significantly. No substantial discrepancies in lymph node ADCLn values or short axis diameter were found among cN1-3 stages, whereas PFLn values were distinct between cN1 versus cN2 stages (p=0.03). In the patients without neoadjuvant RCT no statistically significant differences in the assessed functional parameters on the basis of pathologic stage were found.

CONCLUSION

This study illustrates that ADC as well as MR perfusion values can be analyzed with good interobserver agreement in patients with rectal cancer. Moreover, MR perfusion parameters may allow accurate differentiation of tumor stages. Both findings suggest that functional MRI parameters may help to discriminate T and N stages for clinical decision making.

Thyroid cancer following nuclear tests in French Polynesia

BACKGROUND

Between 1966 and 1974, France conducted 41 atmospheric nuclear tests in Polynesia, but their potential health effects have not previously been investigated.

METHODS

In a case-control study, we compared the radiation exposure of almost all the French Polynesians diagnosed with differentiated thyroid carcinoma between 1981 and 2003 (n=229) to the exposure of 373 French Polynesian control individuals without cancer from the general population. Radiation exposures were estimated using measurements after the nuclear tests, age at time of each test, residential and dietary information.

RESULTS

The average thyroid dose before 15 years of age was about 1.8 mGy, and 5% of the cases and 3% of the controls received a dose above 10 mGy. Despite this low level of dose, and after adjusting for ethnic group, level of education, body surface area, family history of thyroid cancer and number of pregnancies for women, we observed an increasing risk (P=0.04) of thyroid cancer with increasing thyroid dose received before age of 15 years, which remained after excluding non-aggressive differentiated thyroid micro-carcinomas. This increase of risk per unit of thyroid radiation dose was higher (P=0.03) in women who later experienced four or more pregnancies than among other women.

CONCLUSION

The risk estimate is low, but is based on limited exposure data. The release of information on exposure, currently classified, would greatly improve the reliability of the risk estimation.

Overall and cause specific long term mortality following childhood cancer: The role of cancer treatment

9520

Background: A multi-centre French cohort study was performed to evaluate the role of treatment in the long-term overall and cause-specific mortality among childhood cancer survivors. Methods: This study cohort included 3,057 patients treated for a solid tumours before the age of 17 between 1942–1986, in 5 French centres and who survived at least 5 years from diagnosis. Detailed clinical and therapeutic data were extracted for each patients from medical records. For 2,081of the 2,178 patients who received radiotherapy, radiation doses were estimated at 188 anatomical sites, including heart (7 sites) and lungs (10 sites). 98% of patients were identified in French National Registry of Physical Persons (RNIPP) and we obtained the death causes of 95% of dead patients. Overall and cause-specific mortality standardized ratios (SMR), absolute excess risk (AER) of death were studied using Poisson regression. Results: 50% of patients were treated by chemotherapy (CT) plus radiotherapy (RT), 22% by CT alone and 21% by RT alone. During an average follow-up of 25 years, 465 patients dead. The overall SMR was 7.3 (95% CI: 6.7–8.0) and AER was 6 deaths per 1,000 person-years. SMR for death due to cancer other than the 1st cancer (SC) was 16.1 (95%, CI 13.5–18.9). SMRs were significantly elevated for non-cancer overall mortality, infectious and parasitic diseases, diseases of the circulatory, nervous and respiratory system, congenital anomalies, symptoms, signs and ill- defined conditions’ (SMRs of 2.6, 15.7, 6.4, 8.5, 4.6, 3.2, respectively). RT was associated an increase in the risk for overall and SC related deaths (RR = 2.0; 95% CI: 1.5–2.7; RR = 1.8; 95% CI: 1.1–2.9; respectively). CT was associated with an increased risk for overall, SC and non- cancer related deaths (RR = 1.6; 95% CI: 1.3–2.0; RR = 1.9; 95% CI: 1.2–3.0; RR = 1.8; 95% CI: 1.1–2.9 respectively). We were not able to find any evidence for an interaction between CT and RT, whatever the end point considered. Among the 26 circulatory deaths, 24 received RT, the mean radiation dose of the heart (P=0.0006) and treatment with spindle inhibitors (P=0.009) were significantly associated to death by cardiac disease. Conclusions: In the future, death due to cardiac pathologies could be an important issue for long term survivors of childhood cancer.

No significant financial relationships to disclose.

Is cancer mortality increasing in France?

Long-term trends in cancer mortality are reported by site. Overall, cancer mortality has been decreasing in France since 1987 in the male population and since 1968 in the female population. Improvement in treatments and diagnosis should lead to persistently declining mortality rates, unless the tobacco epidemic reverses the trend in female mortality.

[Cancer prevalence in France]

To measure the frequency of cancer in a given country on a given year, one can use the number of new diagnosis or the number of deaths, but one can also consider the number of patients who have had a cancer diagnosed in the past and are still alive. This indicator is called prevalence. We present here estimations for the prevalence of cancer at 5 years in France, by sex and by site of cancer. These estimations are based on the number of new diagnoses in 1995 and on survival rates observed in Europe. In year 2000, 620,000 persons (310,000 men and 310,000 women) were followed up in France for a cancer diagnosed within the last 5 years. The most prevalent cancers were breast (136,000 cases), colorectal (91,000 cases) and prostate (83,000 cases) cancers.

[Evaluation of diagnostic methods]

AIM

Describe the statistical tools for the evaluation of a diagnostic test.

MATERIAL AND METHODS

Description of the methods and practical examples based on published data.

RESULTS

The following methods are described: 1) reproducibility of a measurement, both for a qualitative and a quantitative result, 2) comparison of a new diagnostic test to a reference test, 3) comparison of two diagnostic tests, 4) sample size computation.

CONCLUSION

The tools required to evaluate diagnostic tests rigorously are available and simple. They should be used more often.

[Infection prophylaxis in open leg fractures. Comparison of a dose of pefloxacin and 5 days of cefazolin-oxacillin. A randomized study of 616 cases]

THE PURPOSE OF THE STUDY

Was to compare the efficacy of a single 800 mg injection of Pefloxacin (PF) versus 2 days of cefazolin (1 gr.Q.6 H) followed by 3 days of oxacillin (1 gr.Q.8 H) in patients with an open tibial fracture and to examine the predictive factors for infection. A double-blind double dummy, multicentric, randomized trial was performed. 616 adults with an open tibial fracture requiring single-stage bone coverage were included. The end point was wound infection within 3 months.

RESULTS

Within 3 months, 21/316 patients were infected in the PF group (6.6 p. 100) versus 24/300 in the CZ-OX group (8 p. 100), the difference was not significant (95 p. 100 Cl for difference: -4.8 p. 100 to 2.1 p. 100). Twenty one strains were isolated in 18 infected patients in the PF group, and 27 in 20 patients in the CZ-OX group. Negative gram bacteria were less frequent in the PF group (10 p. 100) than in the CZ-OX group (48 p. 100), and positive gram bacteria were more frequent in the PF group (90 p. 100) than in the CZ-OX group (52 p. 100). Independent risk factors for infection were severe contamination, widespread contusion, unstable fracture, positive sample in the emergency room and at the end of surgery. Resistant infecting bacteria rate was 24 p. 100 in infected cases.

CONCLUSION

There was no difference in infection rates after surgery for open tibial fractures between a 800 mg injection of Pefloxacin and 2 days of pephazolin followed by 3 days of oxacillin. Infecting bacteria were mainly nosocomially acquired.

Diagnosis of nosocomial pneumonia in cancer patients undergoing mechanical ventilation: a prospective comparison of the plugged telescoping catheter with the protected specimen brush

STUDY OBJECTIVES

Quantitative culture of protected samples of lower respiratory tract secretions obtained by a fiberoptic protected specimen brush (PSB) is widely accepted for the diagnosis of ventilator-associated pneumonia (VAP), but this diagnostic procedure is time consuming, expensive, and may give rise to iatrogenic complications, especially in cancer patients who often present with thrombocytopenia. The plugged telescoping catheter (PTC) could be a satisfactory alternative to the PSB in this setting. The aim of the present study was to evaluate the interest of the PTC to diagnose VAP in ventilated cancer patients.

DESIGN

A prospective observational study.

SETTING

A 15-bed medical-surgical ICU in a comprehensive cancer center.

PATIENTS AND INTERVENTIONS

Over a 9-month period, 42 patients suspected of having bacterial VAP during mechanical ventilation underwent 69 bronchial samplings: a blinded PTC and a fiberoptic PSB were performed successively in each case. A positive culture for both sampling procedures was defined as the recovery of > or = 10(3) cfu/mL of at least one potential pathogen. The PSB result was taken as the reference standard.

MEASUREMENTS AND RESULTS

The overall agreement between the techniques was 87% (60/69). PTC had a sensitivity of 67%, a specificity of 93%, a positive predictive value of 71%, and a negative predictive value of 91%.

CONCLUSIONS

We conclude that the accuracy of the blinded PTC compares well with that of the PSB for the diagnosis of VAP in cancer patients. The sensitivity of the PTC observed herein, which is slightly lower than that described in previous studies, may be due to the blinded nature of the method: the indications for initial or secondary coupling with a directed sampling method in patients with suspicion of localized pneumonia remain to be determined.

Epidemiology of bacterial infection during management of open leg fractures

In a randomised double-blind trial conducted between 1990 and 1994, 616 patients from 43 centres, pefloxacin (group P, 316 patients) and a cefazolin-oxacillin combination (group C, 300 patients) were compared in the prophylaxis of bone infection after grade 1 and 2 open leg fractures. Samples were obtained at emergency, before and during surgery, and from drain aspirates. Antimicrobial susceptibility, slime production and adherence properties of the bacteria were tested. Cultures at emergency and before surgery showed similar distributions of gram-positive and gram-negative bacteria in both groups, while wound closure and infecting isolates showed prevailing gram-positive bacteria in group P and gram-negative bacteria in group C. Positive cultures at each stage were correlated with the occurrence of infection but were not predictive of the infecting species, which were nosocomial bacteria in most cases. Positive cultures at wound closure warn of a higher infection risk. Twenty-one of 316 (6.6%) patients in group P and 24 of 300 (8%) in group C were considered infected within 3 months. The difference is not significant (chi-square test = 0.42; P = 0.51). Infecting strains were isolated from 38 patients (group P, 18; group C, 20). Infecting species, although not predictable, appear to be those escaping the spectrum of the prescribed antimicrobial prophylaxis.

[Current trends in lung cancer mortality in France]

Lung cancer is the first cause of death from cancer in males in France. This cancer is responsible for 19,000 deaths in males and 3,000 deaths in females. We studied the geographical and temporal variations in lung cancer mortality in France. The average increase in mortality clearly decreased in males, changing from 2.4% between 1971 and 1985 to 0.7% between 1985 and 1992. In females, this tendency is reversed. Even though the rates were stable and very low before 1971, we have since observed a progressive increase which has intensified during the past years. Thus the average annual increase changed from 1.5% between 1971 and 1985 to 3% between 1985 and 1992. The geographic comparisons between the two studied periods (1971-78 and 1987-92) showed important differences between males and females. The geographic disparities among males were stable between these two periods. The excess observed mortality rate was maintained in the north-east. Among females, few geographic variations were observed during the first period. The second period however, showed distinct excess mortality rates in urban areas and large conglomerations as compared to the rest of France. In summary, the increase in the mortality rates for lung cancer is more pronounced in females and seems to have diminished in males, particularly in urban areas. This tendency started in the 1980s.

Bacteremia and severe sepsis in adults: a multicenter prospective survey in ICUs and wards of 24 hospitals. French Bacteremia-Sepsis Study Group

To examine the relationships between bacteremia and severe sepsis and assess the influence of characteristics of infection on the risk of severe sepsis and outcome of bacteremia, we analyzed all clinically significant episodes of bacteremia occurring during a 2-mo prospective survey of 85,750 admissions to adult wards and intensive care units (ICUs) of 24 hospitals in France. Incidence rates of bacteremia and of bacteremic severe sepsis were 9.8 (95% CI: 9.2 to 10.5) and 2.6 (95% CI: 2.2 to 2.9), respectively, per 1,000 adult admissions; these rates were eight and 32 times higher in ICUs than in wards, respectively. Independent risk factors for severe sepsis during bacteremia included age (p < 0.001) and an intraabdominal (p < 0.001), pulmonary (p < 0.001), neuromeningeal (p = 0.004), or multiple (p < 0.001) source of bacteremia, but not categories of organisms involved. The probability of death at 28 d after bacteremia was 25% (95% CI: 23% to 29%), and was 54% (95% CI: 48% to 61%) in patients with bacteremic severe sepsis. The risk of death after bacteremia increased with age (p < 0.001), a rapidly or ultimately fatal underlying disease (p < 0.001), and the presence of severe sepsis (p < 0.001), shock (p = 0.03), and infection caused by gram-positive organisms other than coagulase-negative staphylococci, relative to other organisms (p < 0.001). A primary urinary tract source of infection was associated with a better prognosis (p = 0.03). We conclude that whereas sources of infection influence both the risk of severe sepsis and the outcome of bacteremia, the microbiologic characteristics of infection influence only the outcome, with gram-negative organisms and coagulase-negative staphylococci posing a lesser risk than other organisms.

[Mortality from cancer in France. Changes between 1950 and 1989 in the population aged 35-64]

In the French population aged 35-64, cancer mortality increased yearly by 1 percent in males and decreased yearly by 0.6 percent in females between 1950 and 1989. In males, the increase is mostly due to the sites associated with tobacco and alcohol. The important increase of lung cancer is related to the increase in tobacco consumption from 4.7 g per adult per day in 1950 to 6.3 g in 1976. The increase observed in head and neck cancers is related to tobacco and alcohol. In females, the moderate decrease is due to the decrease observed in uterine cervix and stomach cancer mortality, uncompensated by the increase in breast cancer. Contrary to what is observed in the USA, there is no marked increase in lung cancer mortality for women.

Trends in cancer mortality, France 1950-1985

Trends in mortality for main cancer sites in France between 1950 and 1985 are presented by sex. In the population aged 35-65, where long term trends can most reliably be assessed, an overall 1.1% mean annual increase is observed for males and a 0.6% mean annual decrease is observed for females. For males, this increase in total cancer mortality is mostly due to the sites associated with tobacco and alcohol. The important increase for lung cancer, and lesser increases for bladder, pancreas and kidney cancers are related to the increase in tobacco consumption from 4.7 g per adult per day in 1950 to 6.3 g in 1976. For cancer sites associated with alcohol and tobacco, namely oesophagus, pharynx, larynx, tongue and mouth, mortality is increasing similarly for males and for females, although these cancers are much less frequent among females. For females, the overall moderate decrease is mostly due to the decrease in cervix and stomach cancer mortality, uncompensated by the observed increase in breast cancer; there is no marked increase in lung cancer mortality for women, contrary to what is observed in other Western countries.

Two-day cefamandole versus five-day cephazolin prophylaxis in 965 total hip replacements. Report of a multicentre double blind randomised trial

The aim of this trial was to compare a 5-day course of cephazolin with a regimen of 2 days of cefamandole in 965 total hip replacements (488 in the cefamandole group and 477 in the cephazolin group). The effect of the prophylactic antibiotic on the bacterial colonization of drains (mean duration of drainage: 3.2 +/- 0.3 days) and on the susceptibility of colonizing organisms was assessed. No significant difference was observed in the percentage of infected drains between the two groups. The cefamandole group had a lower rate of Gram-negative organisms (23% versus 44%, p less than 0.01). The rate of deep infections within one year after operation was 0.7% in the cefamandole group versus 0.5% in the cephazolin group, and the difference is not significant. Cefamandole given for two days appears to be an effective prophylaxis against sepsis in total hip replacements.

[Methodological framework of the evaluation of systematic screening and treatment of preexistent lesions of the colon and the rectum]

Among the conditions which need to be filled when generalizing the mass screening of polyps in view of the secondary prevention of colorectal cancers, three are already present: 1) it is a frequent and serious cancer; 2) there is an affiliation between benign tumours and cancer; 3) an effective non-mutilating treatment of benign tumours is available. On the other hand, two additional conditions remain unfilled and yet lie within the domain of research by methodologically rigorous studies: the setting up of a screening test with a high cost-effectiveness relationship; the epidemiological demonstration of the decreasing incidence of colorectal cancers following screening and treatment of precancerous lesions.

[Secondary prevention of cerebral infarction caused by atherosclerosis. 3-year comparison of flurbiprofen and an ergot derivative]

A multicentre controlled trial was conducted on 383 patients to compare the effectiveness of flurbiprofen (100 mg/day) and an ergot derivative in preventing cerebral infarction. The end-point of the trial was recurrence within 3 years of treatment with one or the other drug of a fatal or non-fatal cerebral infarction. Only those patients who had already experienced an established and disabling ischaemic accident in the carotid or vertebro-basilar territory were included; 88% of these entered the trial less than 6 weeks after the accident. Sixty-one patients had recurrent cerebral infarction during the 3-year observation period: 22 in the flurbiprofen group and 39 in the ergot derivative group (p less than 0.02 log rank test adjusted by centre). The actuarial recurrence rates in the two groups were 13% and 21% respectively. These results concur with those of other trials involving aspirin to demonstrate the value of antiplatelet aggregation drugs in the secondary prevention of atherothrombotic cerebral infarction.

[Systematic hip roentgenograms in infants of 4 months of age in the screening for congenital dislocation of the hip (author's transl)]

The authors report the results of a statistical study undertaken for the screening of congenital dislocation of the hip. 961 children born between September 24, 1977 and June 30, 1978 were examined. Congenital dislocation of the hip was diagnosed in 9 (0.9 % of the cases). Out of these, 4 had no clinical sign of dislocatability at birth. The only determination of acetabular angles cannot be relied upon and qualitative criteria such as ilium thickness must be added.

[Statistical study of the relationships between the etiology and clinical picture of cerebral palsy]

846 children with cerebral palsy were examined and 642 were selected for a statistical study by correspondence analysis. The aim was to identify without any prior assumptions, the relationships between the aetiological factors and the clinical findings. The study was completed by conventional statistical analysis of 584 of the cases. Small birth weight and a history of abnormal pregnancies was associated with a cerebral palsy affecting both legs, and often with a squint. Resuscitation was associated with athetosis and abnormalities of posture and behaviour. If the resuscitation lasted for more than 15 minutes or there were certain problems during delivery, severe abnormalities of both arms and major speech difficulties were observed. Resuscitation for less than 15 minutes or for an unknown time or intractable vomiting during pregnancy was associated with quadraplegia. Hemiplegia was related to post natal events but the aetiology was not always known. Foeto-maternal incompatibility was associated with athetosis, deafness, severe speech problems and ophthalmoplegias.

[Inquiry on the future of newborns treated in intensive care units for children. III. Neurologic anomalies]

This study concerned newborns admitted between 0 and 10 days of life at the intensive care unit of the Hospital St-Vincent-de-Paul from 1969 to 1972. They were followed later as outpatients. Out of 1,607 newborns admitted, 1,126 survived (average mortality: 30%). 532 were examined after one year, 397 after two years. On the whole prognosis may be considered as good: at 2 years of age, 8% had major neurologic abnormalities; 4% minor abnormalities, no increase in the percentage of major neurologic abnormalities between 1969 (6%) and 1972 (5%), whereas mortality decreased from 36 to 24%. The various types of neurologic deficits were analyzed, according to their effects on rehabilitation (4% had severe retardation, 11% moderate retardation). The sensory involvement (3%) and intercurrent seizures (10%) were also analyzed. According to the bias of the Unit in recruitment, this enquiry concerned children close from term or medium premature children (B.W. 1,500 g) : this diminishes the true rate of the neurologic deficit. The relationships between etiology of neonatal distress and delayed neurologic abnormalities are emphasized.

[Survey on the fate of newborn infants treated in pediatric intensive care units. II. Respiratory sequelae]

Five hundred sixty children treated at the neonatal period (between 1969 and 1972) were reexamined when they were 1 and/or 2 years old. At 2 years of age, the rate of anomalies considered as probable respiratory sequellae of the neonatal disease, was 10%. In this population, hyaline membrane disease was responsible for nearly 2/3 of the respiratory sequellae observed at 2 years of age, whereas it concerned less than 1/3 of the population under study. The overall prognosis of neonatal disorders for which treatment in an intensive care unit was required during the 4 years under consideration, is clearly improving, since the decrease of death-rate is not associated with an increase of respiratory sequellae among the survivors.

[Prognosis for infants treated in pediatric intensive care units]

The first part of the inquiry reported herein is dealing with the diagnostic distribution and the death-rate of a population of 1,607 newborns, admitted for vital distress and treated in an intensive care unit for children from 1969 to 1972. Global death-rate reached 30%. 49% of the patients were admitted for different neonatal respiratory diseases: they were responsible for 31% of the deaths. Perinatal cerebral suffering was the principal cause for admission for 15% of the newborns: with a 40% death-rate, it was responsible for 20% of deaths. However, from 1969 to 1972, global death-rate was constantly decreasing, from 36 to 24%. This improvement concerns especially the respiratory diseases and the perinatal cerebral suffering.

Natural history of ventricular septal defect. A study involving 790 cases

The development of 790 untreated patients affected by ventricular septal defect (VSD) has been the object of a 25-year study. Of these patients, 72% had had at least one catheterization; 13% had several. The mean observation interval is six years, and the average age at the latest data is 19.5 years. This study covers 4717 patient-years. For the entire population, the incidence rate or aortic regurgitation is 6.3% (4.3 for 1000 patient-years) and that of bacterial endocarditis is 3.7% (2.4 for 1000 patient-years). Twenty-five patients died, 15 of them between the ages of one and 39. Of the 499 cases with several clinical examinations, 71% remained stable. In 21%, changes suggesting some level of closure developed; in 7%, infundibular stenosis began to evolve and in 1% pulmonary vascular disease began to appear or became accentuated. These different rates are studied and discussed in relation to patients' age, VSD type, and various follow-up characteristics.