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Biomedical subjects

P Philippe

Publications and source records attributed to P Philippe.

At least 19 recordsLinked to original sources
PubMed1991

Pediatric nonrhabdomyosarcomas of the extremities. Influence of size, invasiveness, and grade on outcome.

Surgery alone or supplemental radiation is effective in local control in a majority of patients with nonrhabdomyosarcoma of the soft tissue. To determine the factors influencing subsequent survival, a retrospective review of 64 children with nonrhabdomyosarcoma of the soft tissue of the extremities was performed. Using the American Joint Committee on Cancer staging system, 32 patients had noninvasive T1 lesions, and 31 of these patients survived disease free. Twenty-two patients had lesions that were smaller than 5 cm; 19 of these lesions were grade G1-2. All 22 patients survived. Ten patients had tumors that were 5 cm or larger, and all were G1-2; nine of these patients survived. Thirty-two patients had invasive (T2) lesions; seven of these lesions were smaller than 5 cm, but four were G3. Only one patient survived. Eighteen (72%) of 25 lesions that were 5 cm or larger were G3. Fifteen (83%) of these 18 patients underwent relapse, with 12 patients dying of the disease. Important prognostic factors included G3 lesions, with a 72% (18 of 25 patients) failure rate, and T2 lesions, which were generally larger than 5 cm, of higher grade, and underwent relapse more frequently than T1 lesions. These patients with histologic G3 and T2 lesions may benefit from chemotherapy.

Adolescent↗
PubMed1991

Twinning in susceptible mothers. An exploratory study of international data by Payami's models suggests "reproductive maturity" as a risk factor.

An attempt has been made to apply Payami's models to maternal age-specific twin birth prevalences in several countries. The models disclose the heterogeneity of a cohort and spell out the risks to susceptible members (who will actually get the disease) according to age (or time). Payami's method specifies that the typical cohort of susceptibles is ascribed to two exposures: a potent and generalised exposure and a very low or no risk secondary exposure. The models have been adjusted to international data from current as well as old populations, of Occidental and Japanese origin. Results show that cohorts of twin-prone mothers aged 25 to 45 are homogeneous. A single dominant etiology is suggested which applies to both MZ and DZ twins. Heterogeneity, from 10% to 25%, is present in all countries whenever the 20-24 age group is involved. A separate study of illegitimate twin births from Denmark reduces the heterogeneity and shows that MZ illegitimate twin births are due to a secondary exposure responsible for a distinct twinning etiology. The age-specific risks of a MZ illegitimate twin birth are much higher than those of any comparison group, and are constant until age 35 years. This suggests a single-hit exposure akin to a neuroendocrine stimulus which short-cuts the usual age-dependent etiologic pathway. MZ and DZ twins both experience the same maternal age specific risks, an observation which underscores the common etiology of both types of twins. Risks increase with age from 20 to 45 years. The pattern according to age varies among countries and time periods. Occidental populations have a pattern varying from an exponential to a more linear increase in old and recent populations, respectively. Only present-day Japan displays a logarithmic-like growth curve. The concept of "reproductive maturity" is introduced, and related to the secular trend of the DZ twin birth risk and to its variation across countries. Two new conclusions are drawn: a) The higher the rate of reproductive maturity, the less the DZ twin birth risk and, b) Reproductive maturity determines the maternal age-specific gonadotropin levels.

Adult↗
PubMed1991

Box-Jenkins modeling of chronological series of twin births and single births.

A time-series analysis by Box-Jenkins modeling of the monthly observations of twin births and singleton births was attempted. The study is population based. The single-birth series has been matched to the twin-birth series for maternal birth cohort, parity of the twin birth, and residence of the parents. Three-hundred forty-one twin pairs and 340 singleton births were grouped into chronological series spanning 72 months of observation. Univariate and bivariate time-series analyses were used. Box-Jenkins modeling shows that both series share the same basic demographic and reproductive risk factors, such as ovulation and conception rates, abortions, sexual intercourse, and the less well-known random events that determine the time of delivery. These factors are randomly related to both birth processes but exert a more important influence on twin births. Beyond these crude features, twin- and single-birth series differ by the frequency of their seasonal cycle. Twin births show low-frequency variations because of a rather limited number of factors that impinge markedly on the twinning process. Single births are subjected to higher frequency variations that can be ascribed to a greater number of structuring factors, the action of which is less pervasive. Only the January peak is common to both types of births. Aside from the common features, the bivariate analysis shows that both series of births are independent, neither being related to the other. It is concluded that the subtle structuring of both processes is largely distinct. The large fraction of the unaccounted variation of each birth process (about 70%) suggests that most of the variation is due to as yet unidentified factors. The search for environmental and geocosmic factors at the origin of conception and confinement should be considered in future undertakings.

Birth Order↗
PubMed1990

[Iridociliary melanoma with cataract (iridocyclochoroidectomy followed by extra-capsular extraction with pseudophakia)].

Description of a case of malignant melanoma of iris and ciliary body in a man of 59 years old. Clinically an interesting sign was the mahogany discolouration of the greyish cataract in the quadrant in front of the tumour. The tumour was removed following the technic of H.-S. STALLARD. Eighteen months later an E.C.C.E. was performed and a "Meur" model of implant inserted (optic in the post chamber and haptics in anterior chamber). Visual acuity in 1989 was 6/6 with glasses and a single binocular vision was recovered.

Cataract↗
PubMed1989

Conceptive delays of twin-prone mothers: a demographic epidemiologic approach.

We studied the time interval to the first birth and to the twin birth using statistical and mathematical models in two groups of mothers, those with twins and those with singletons, from the same population. We made use of a pair-matched case-control design. We treated the maternal birth cohort and parity as confounders and thus as controlled. We also investigated the sex of twin pairs as an interactive variable, employing such methods as survival curve testing and using geometric, gamma, and exponential distributions where appropriate. The expectations derived from the mathematical models yield numerical estimates of fertility components. The results suggest that unlike-sex twin-prone mothers have higher fecundity than controls when they conceive singletons. Further, fecundity appears high and unimpaired before the birth of twins. Mothers of like-sex twins experience somewhat shorter and but more variable birth intervals than corresponding controls before the birth of twins, suggesting within-group heterogeneity. Specifically, the birth of like-sex twins is preceded by low fecundity and a short period of postpartum amenorrhea. Biologically, like-sex (presumably monozygotic) twin-prone mothers have a hormonal defect related eventually to menopausal status that interferes with ovulation and perhaps with lactation. As for unlike-sex twin-bearing mothers, they probably experience a displacement of their maximum fertility potential toward early reproductive life and an extension of their menstrual life. From a methodologic standpoint, the study of the fertility of twin-prone mothers cannot proceed without estimates of the fertility components of birth intervals, as these intervals do not lend themselves to straightforward analytical interpretations by statistical analyses.

Adult↗
PubMed1989

[Primary malignant melanoma of the bladder. Apropos of a case].

The authors report about a case of a primitive melanoma of the bladder that a man aged 77 years suffered of. The diagnosis was carried-out with certain difficulty on fragments of endoscopic resection and was discussed from the clinical facts as well as from the anatomo-pathological results and, more particularly, from the immuno-histochemical results. This study makes it possible that a comparison be made with those rare cases observed on a world-scale basis which are described in the literature. As far as the bladder is concerned, it constitutes also an attempt of histogenetic explanation of this kind of tumor.

Aged↗
PubMed1988

The end of reproductive life in mothers of twins: epidemiologic analysis of a large data base.

A case-control study was conducted on the termination of menstrual life on mothers of twins. It involves a much larger data base and finer analyses, and makes use of the same methodology of a previous study. The time interval between the twin and the last confinement proved to be shorter in twin-bearing mothers than in a matched set of controls with singletons only after blocking of the effect of birth order, and despite the similarity of maternal age at delivery and confinements numbers. Mothers of like-sex twins only appeared to terminate reproductive life earlier than controls. The separate study of maternal age at twin confinement shows that the earlier the twin birth the shorter the menstrual life thereafter. Both like-sex twin births and early maternal age at delivery of a twin pair have the same shortening effect on subsequent menstrual life without clear evidence of additivity of effects as if both occurrences were alternatives with similar biological effects. Comparison of the results of the current study with those of our earlier analysis shows consistency on above results. However, the current study could not reproduce previous results on the role of unlike-sex twins or late maternal age at delivery on time to last confinement; yet, they cannot be discarded. It is suggested that increased power of interaction analyses and tighter matching of controls with respect to sex might improve the conclusions of subsequent studies.

Adult↗
PubMed1987

Cyclic variations of twin births at Isle-aux-Coudres: a case/control approach.

Twins and singletons were matched for several confounding factors. The monthly distribution of twin births and that of singleton births were compared with a uniform allocation of births over the year. Opposite seasonal variations emerged that were confirmed by a case/control comparison. Twins occurred more often in winter and early spring while singletons proved to be relatively few; singleton peaked in the fall season when the risk of a twin birth was low. These trends held across maternal age at birth and the time period of birth. Results suggest that the conception of a twin pair is highest in spring and early summer and lowest in winter. The role of sunlight in the twinning liability is discussed along with the role of sexual intercourse. That twin-prone mothers are usually more fecund in spring and early summer is a distinct possibility.

Birth Rate↗
PubMed1986

[Cytogenetic study of 20 cases of refractory anemia].

The myelodysplastic syndromes are a group of hematological disorders not yet clearly defined. The authors describe the chromosomal aspects of 20 cases observed in the region of Clermont-Ferrand in comparison with the bibliographical data.

Aged↗
PubMed1985

Genetic epidemiology of twinning: a population-based study.

We report on kinship analysis of mothers with twins and a study of their ancestors and inbreeding. A pair-matched case-control design supports the analyses. Nearly as high a number of ancestors was found at the origin of cases as in control individuals. Study cases were less inbred than control subjects, but their kinship was higher, especially for unlike-sex twins born after age 30 years of mothers and, but less so, for like-sex twins born to mothers younger than 30 years. The results indicate a genetic origin of both types of twins and possibly a highly spread gene with dominant or co-dominant expression.

Adult↗
PubMed1985

[Generation and evaluation of etiologic hypotheses in epidemiology].

So far the problems of the generation and evaluation of etiologic hypotheses have been of too little concern to epidemiologists. Epidemiologic research usually deals with two fundamental etiologic questions: the first is 'why' an epidemiological phenomenon occurs; the second is 'how', and the question relates to the mediating mechanism. After having defined the nature of a valuable working hypothesis, we identify several ways by which hypotheses might be merged, and discuss for each of them the corresponding problems of evaluation. It is advocated that 'biological' (clinical) induction is a promising way of gaining insight into the etiology of disease. 'Statistical' induction, on the other hand, may be a useful though precarious way of generating hypotheses, mainly because of evaluation problems. As to deductive thinking, sometimes based on the process of analogy, its use is confined to rather well developed fields of knowledge. Furthermore, deductive thinking may be plagued by logical errors if the biological model of the studied disease is inadequate. Finally, Popperian deduction is also showed to be subjected to logical flaws if the causal model of relationships is poorly grounded into the biology of disease; specifically, the point is made that the refutation or confirmation of hypotheses is not straightforward and may be prevented in cases of complex biological situations. We conclude that epidemiologic analysis may be furthered by contacts with clinicians who would be of invaluable help in formulating and the testing of hypotheses, by study designs devised to reject specific models of disease, and by the rooting of putative causes of disease beyond simple risk markers.

Disease↗
PubMed1985

[Giant cell arteritis of the uterus. Apropos of a case].

Histopathologic examination can sometimes provide unexpected indications. In this report giant cell arteritis of uterine vessels was found. It permitted to explain biological abnormalities presented by the patient who suffered of a particularly inflammatory syndrome. These abnormalities had been initially attributed to repetitive urinary infections due to third-degree uterine prolapse (associated bladder prolapse). The diagnosis of periarteritis nodosa (P.A.N.) was supported with the results of muscular biopsy. This diagnosis was confirmed by evolution: it showed secondary renal and hepatic damages. Finally three months after corticotherapy was undertaken, the general state was very improved.

Aged↗