Biomedical subjects
Publications and source records attributed to P Delvoye.
The clinical diagnosis and treatment of cutaneous cancers represent a frequent situation in cancerology. About one third of all human cancers take their origin from the skin. The general practitioner and the dermatologist-oncologist play the key role in that field of health care.
More than 15 common or specific dermatoses may be worsened during the premenstrual phase. Acne, herpes simplex and the autoimmune progesterone dermatitis represent typical examples.
The Mosan Study Group of Pigmented Neoplasms was founded about 15 years ago. It has collected more than 20,000 cutaneous malignancies including melanomas and basal and squamous cell carcinomas. The incidence of these cancers is on the rise in Wallonia. In particular, malignant melanomas represent a spectrum of emerging cancers characterized by a proteiform biological outcome. They mostly affect young women. The major risk factor appears to be iterative and unwise ultraviolet exposures. The prevention of melanomas is basically founded on such a dogma and accordingly relies on sunscreens. However, controversies about their beneficial effects are rife and fueled by axiomas and contradictory sophisms. At the exception of surgery, the therapeutic options for the diverse types of melanomas do not yet fulfill the scope of evidence-based medicine.
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Mechanical activities developed by cells play a significant role in the embryogenesis, development, and physiopathology of pluricellular organisms. A technique is described to measure in vitro the traction force developed by cells seeded into a three-dimensional polymeric collagen lattice. It is based on the use of strain gauges generating an electrical signal upon tension that is amplified and recorded. The intensity of the signal depends on the number and type of cells, cytoskeleton integrity, concentration of collagen in the lattice support, and fetal calf serum in the culture medium. Skin fibroblasts from humans and animals produce traction forces ranging from 100 to 1000 mg per million cells. In the gel under tension, the cells are in mechanical dynamic equilibrium with their support. It is suggested that the mechanical activity of fibroblasts and the control of the tension that they operate on the lattice support participate in the structural organization of the dermis and in its physiologic tension.
We present a novel approach for improving the management of patients with pigmented neoplasms including malignant melanomas and dysplastic nevi. A cohort of 215 dysplastic nevi and malignant melanomas was studied by cyanoacrylate skin surface stripping (CSSS) and conventional histology. Presence of atypical melanocytes was found in the stratum corneum in more than 95% of malignant melanomas and was always absent in dysplastic nevi. We conclude that this non-invasive technique is rapid, easy to perform, and inexpensive. Its specificity and sensitivity are high enough to be considered by clinicians as an aid for distinguishing dysplastic nevi from malignant melanomas. We recommend this ancillary technique as a screening procedure though not as a substitute for conservative excisional biopsy, when doubt persists in the diagnosis of atypical pigmented neoplasms.
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The mechanism regulating the deposition of basement membrane components (BMCs) in a polymeric structure at the junction with the connective tissues is not yet understood. Cultures and cocultures of epithelial BMC-producing cells (L2 or PER cells) and fibroblasts were prepared in several experimental conditions and the organization of BMCs was studied by immunofluorescence. The pattern of BMCs in pure cultures of L2 or pulmonary epithelial rat (PER) cells consisted of intra- and extracellular granular deposits. At very high density, the cell contours were also underlined by a disrupted network of BMC deposits. A different fibrillar plexus--containing laminin, collagen type IV, and heparan-sulfate proteoglycan resistant to deoxycholate treatment and distant from the cell membrane--was observed in cocultures of L2 or PER cells with fibroblasts. Fibrils of fibronectin and/or collagen type I were most often dissociated from this plexus of BMCs. Similar results were obtained by adding a conditioned medium of L2 or PER cells to confluent fibroblasts, even when the cells were killed. Pure laminin also bound to the fibroblast layer. A coated film of fibronectin or polymeric collagen type I was unable to bind BMC provided by a conditioned medium. It is suggested that molecule(s) synthesized by fibroblasts and deposited in the pericellular matrix are involved in the assembly of BMCs.
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Fibroblasts derived from patients and animals presenting various heritable connective tissue disorders were investigated for the ability to retract a reconstituted collagen matrix. When seeded into gels, dermatosparactic calf and sheep fibroblasts did not exhibit the elongated shape of normal fibroblasts and did not contract the collagen lattice to the same extent as control fibroblasts. In contrast, several cell strains obtained from patients with Ehlers-Danlos syndrome type VII displayed contractile properties for collagen gels similar to controls. Delayed contraction was noted by two strains of fibroblasts from patients with Ehlers-Danlos syndrome type IV, whereas fibroblasts from patients with osteogenesis imperfecta, Marfan syndrome and cutis laxa had normal retraction properties.
A group of women with unknown last menstrual period was studied representing 16% of a total of 22 404 pregnant women recorded using a common perinatal form. Unknown menstrual period is associated with high rates of low birth weight and with low socioeconomic and sociodemographic status. Such characteristics are also associated with a high rate of preterm deliveries. Thus any possible bias introduced in studies of prematurity by ignoring the group of women with unknown last menstrual period should be carefully checked.
When cultivated within a matrix made of reconstituted collagen fibers, fibroblasts derived from skin, tendon, vena cava, and aorta of a normal (N) calf retract the lattice. This effect progresses with time and is related to the density of the cells included in the lattice. Under similar conditions, fibroblasts derived from the skin of 2 dermatosparactic (D) calves do not contract the lattice. Fibroblasts from D tendon and cells from D vena cava and aorta contract the lattice at the same rate and to the same extent as do their normal counterparts. In the lattice, N skin fibroblasts are elongated along the collagen fibers while D skin fibroblasts remain round and develop little cell processes. N skin fibroblasts do not multiply in the lattice while D skin fibroblasts increase in number by a factor of 3 in 5 days. The addition of N skin fibroblasts, in an amount insufficient to retract the lattice, to D skin fibroblasts does not correct their defective capacity. It is suggested that the disturbed relationship between the D skin fibroblasts and collagen fibers is responsible for the lack of architectural organization of the bundles of collagen polymers in the D skin.
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Serum progesterone and prolactin were measured in single blood samples collected from 176 mothers during a lactation period of 2 years and from fifty-six non-lactating, non-pregnant and regularly menstruating women from the Kivu region (Zaïre). On the basis of serum progesterone levels, evidence of corpus luteum activity was obtained in 61% of non-lactating women; but only 20% of non-amenorrhoeic lactating mothers. This suggests an increased incidence of anovulatory cycles and/or cycles with short luteal phases among nursing mothers. The incidence of corpus luteum activity was 8% in amenorrhoeic lactating mothers. In this 8% recurrence of ovulation preceded return of menstruation. Mean serum progesterone was significantly higher and serum prolactin significantly lower in the non-lactating women than in the nursing mothers. This suggests that although ovulation occurs, corpus luteum activity is inadequate in hyperprolactinaemic nursing mothers.
Serum prolactin, LH, FSH, and estradiol were measured in single blood samples collected from 465 nursing mothers in Central Africa (Kivu, Zaïre) during the first 2 postpartum years. Lactating mothers were hyperprolactinemic during 15 to 18 postpartum months. Both serum prolactin and FSH were higher in amenorrheic than in menstruating nursing mothers; the difference was more apparent during the first than during the second year. Mean serum LH and estradiol were significantly higher in menstruating then in amenorrheic nursing mothers during the second postpartum year but not during the first. There was a significant association of hyperprolactinemia with amenorrhea. Furthermore, postpartum, the incidence of amenorrhea declined parallel to that of hyperprolactinemia.
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