Search PubMed⌕ Search

Biomedical subjects

J L Nizet

Publications and source records attributed to J L Nizet.

10 recordsLinked to original sources
PubMed2001

Influence of body posture and gravitational forces on shear wave propagation in the skin.

The body posture and gravitational forces govern in part the intrinsic skin tensile strength because they influence the orientation of the dermal fibre networks. Our objective was to assess changes in shear wave propagation in the skin according to the body posture and orientation of the gravitational forces. The study was performed in 30 middle-aged women with a normal body mass index. The Reviscometer was used to assess the mechanical wave propagation on the volar forearm in extension or flexion. Similar measurements were made on the supra-areolar region of the breast when the trunk was in the horizontal or vertical position. Four measurements were made in each of 4 directions at given angles with regard to the body axis. The device gave reproducible data. Shear wave propagation was influenced by the body posture. The intra-individual variability in shear wave velocity according to the directions of measurements increased when the tissues were in a relaxed position. Skin tensile anisotropy increased in a relaxed body posture. Shear wave propagation may be a convenient non-invasive tool to better identify the natural skin tension lines in the skin, thus refining the orientation of incision during cutaneous surgery.

Adult↗
PubMed2000

Cellulite: from standing fat herniation to hypodermal stretch marks.

There are glaring discrepancies in the microanatomical descriptions of cellulite in the literature. We revisited this common skin condition in women with a microscopic examination of 39 autopsy specimens. A control group consisted of 4 women and 11 men showing no evidence of cellulite. The lumpy aspect of the dermohypodermal interface appeared to represent a gender-linked characteristic of the thighs and buttocks without being a specific sign of cellulite. Incipient cellulite identified by the mattress phenomenon was related to the presence of focally enlarged fibrosclerotic strands partitioning the subcutis. Such strands possibly serve as a physiologic buttress against fat herniation limiting the outpouching of fat lobules on pinching the skin. These structures might represent a reactive process to sustained hypodermal pressure caused by fat accumulation. Full-blown cellulite likely represents subjugation of the hypertrophic response when connective tissue is overcome by progressive fat accumulation. Histologic aspects reminiscent of stretch marks are identified within the hypodermal strands, resulting in clinical skin dimpling.

Adipose Tissue↗
PubMed1982

[Melanogenesis, an expression of the differentiation of cancer cells in culture].

In B 16 mouse melanoma in culture, differentiated cells actively synthesize melanin. They are analysed by cytological and cytochemical methods. When cultured for long periods (several months), melanogenesis is expressed according to a cyclic way, even when maintained in a culture medium of constant composition and without adding any chemical agent eventually able to influence this phenomenon. This spontaneous cyclic activity is analysed and an explanation is given as an hypothesis.

Animals↗
PubMedDate not supplied

Tensile properties of relaxed excised skin exhibiting striae distensae.

Tensile properties of skin determine some important physical attributes of skin. They may be conveniently assessed using recent technologies. The aim of the study was to compare ex vivo the tensile properties of normal looking skin and striae distensae. The Cutometer was used with 2 and 4 mm diameter probes. Skin distensibility values were dependent on the suction force and area of the skin tested. Conversely, tensile ratios yielding elasticity parameters were not affected by the same variables. Although tensile properties of excised normal skin resembled those previously reported in vivo, striae distensae showed markedly different properties in vivo and ex vivo. The ex vivo and in vivo evaluations of the tensile properties and functions of skin are complementary particularly when the connective tissue is abnormal.

Adult↗