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Biomedical subjects

P Bouhanna

Publications and source records attributed to P Bouhanna.

11 recordsLinked to original sources
PubMed2005

Human hair shape is programmed from the bulb.

BACKGROUND: Few biological data on curly hair follicles have been reported in the literature. OBJECTIVES: To investigate the growth and morphology of curly hair follicles. METHODS: Follicles were dissected from scalp skin samples from African, Guyanese and caucasian volunteers and were observed macroscopically, in culture in William's E medium, and by immunohistochemistry. RESULTS: Macroscopic study of scalp biopsies obtained from African volunteers showed that the dermal implantation of follicles was curved with a retrocurvature at the level of the bulb, as opposed to a straight shape in caucasian follicles. The bulb itself was bent, in the shape of a golf club, while both the outer root sheath (ORS) and the connective tissue sheath were dissymmetrical along the follicle. In vitro growth of curly hair follicles was slightly slower than that of caucasian follicles but, more importantly, the curvature was maintained in the hair shaft produced in vitro. As shown by immunohistochemistry, the proliferative matrix compartment of curly hair follicles was asymmetrical, Ki-67-labelled cells being more numerous on the convex side and extending above the Auber line. On the convex part of the follicle, the ORS was thinner and the differentiation programmes of the inner root sheath and hair shaft were delayed. Furthermore, some ORS cells expressed alpha-smooth muscle actin protein on the concave side of the curvature, reflecting a mechanical stress. CONCLUSIONS: Hair curliness is programmed from the bulb and is linked to asymmetry in differentiation programmes.

Biopsy↗
PubMed2002

[Indications for micrograft hair transplantation].

Advances in treatment of androgenetic alopecia have led to the development of novel medical or surgical therapies adapted to the severity of hair loss and balding. Follicular units or tiny micro-graft hair transplants are a fundamental technical progress. This technique leads to the simple and painless permanent restoration of hair in male and female baldness. It provides the patient with a group of 1 to 3 hairs, emerging from a single orifice. The difference between androgenic receptors of occipital areas and those of other areas explains the permanent nature of the implanted hair growth. The degree of male or female androgenetic alopecia can be determined according to Hamilton's static classification or Ludwig's Classification, or it can be measured and monitored more accurately with Bouhanna's Dynamic Multifactorial Classification. The current indications for micro-graft transplantation are

Alopecia↗
PubMed2000

Multifactorial classification of male and female androgenetic alopecia.

BACKGROUND: Various classifications of male androgenetic alopecia have been described. In fact, all the classification schemes proposed so far are only topographic. A more objective, accurate, and detailed approach to classifying baldness is needed. OBJECTIVE: To propose a dynamic multifactorial classification of certain parameters that can be quantitated and computerized. METHODS: A multifactorial classification has been developed to study parameters such as fixed distances of the face, scalp mobility and thickness, and covering power of hair. This includes density, caliber, shape, length, growth rate, and hair color. RESULTS: Classification proved to be efficient during the fluctuations of different parameters in hormonal and minoxidil treatments. It also helps to determine surgical indications of hair transplant and the stage of maximal baldness. CONCLUSION: This approach will lead to a better evaluation of the evolution of androgenetic alopecia in both sexes, either spontaneously or under treatment.

Alopecia↗
PubMed1997

[Current treatment of androgenetic male and female alopecia (with the exception of hormone treatment)].

Various non-hormonal therapies, either prescribed systemically such as certain hair-specific vitamins, or applied via the topical route, such as 2% Minoxidil, permit a normalisation of androgenic hair loss. The trichogenic action of these products should be verified in each individual with a comparative study using a trichogram and a phototrichogram. Any alopecia, be it large or small, may cause aesthetic discomfort. Currently, no medical or cosmetic product can give hope for a discernible and definitive hair regrowth. Only a micrograft reimplantation, hair by hair, produces tangible, aesthetically-denser hair in the bald region.

Alopecia↗
PubMed1990

[High pedicle scalp flaps].

A retrospective study of 207 transposition flaps with a high pedicle of various sizes and locations allows a better understanding of the esthetic effects, the reliability, the complications and the indications of this hair replacement surgery. Four kinds of flaps with a high pedicle have been transposed separately or jointly for an immediate correction of pattern baldness. The long flaps are delayed but the short flaps are transposed in one session without delay.

Adult↗
PubMed1989

Topical minoxidil used before and after hair transplantation.

A 2% solution of topical minoxidil was applied on the recipient bald scalp of 16 patients aged 25 to 52 years with Hamilton classifications of androgenetic alopecia from III to VI. Therapy was begun 4 weeks before surgery, was interrupted for 3 weeks, and was started again and continued for 3 months. Four-millimeter donor grafts were inserted into 3.5-mm recipient sites. Follow-up utilizing macrophotography was done for 3 months on 4 grafts near a tattooed area. In 71% of the 64 grafts, partial or total hair is still growing without the shedding that usually occurs 2-4 weeks after transplantation. Topical minoxidil seems to be an adjunct for a better evolution of grafts after hair transplantation surgery.

Administration, Topical↗