Ghrelin stimulates myogenic differentiation in a mouse muscle satellite cell line and in primary cultures of bovine myoblasts.

Ghrelin is an acylated hormone that influences food intake, energy metabolism and reproduction, among others. Ghrelin may also stimulate proliferating myoblast cell differentiation and multinucleated myotube fusion. The aim of this work was to assess the effect of human ghrelin (hGHRL) and human ghrelin fragment 1-18 (hGHRL1-18) on myoblast differentiation by means of mRNA expression and protein level. Two types of cells were tested, the cell line i28 obtained from mouse skeletal muscle and primary cultures of bovine myoblasts. Both ghrelin and its N-terminal fragment hGHRL1-18 were used at concentrations of 0, 0.01, 0.1, 1, 10 and 100 nm. Treatments were applied to pre-confluent cultures and were maintained for 4 days. We determined that between 0.1 and 100 nm, hGHRL and hGRHL1-18 had similar effects on myogenic differentiation of i28 cells (p < 0.01). On the other hand, only the higher concentrations (10 and 100 nm) of hGHRL stimulated bovine myoblast differentiation. These results could be attributed to the presence, in both i28 cells and in bovine myoblasts, of the mRNA for GHS-R1a and CD36 receptors. The use of ghrelin in livestock production is still questionable because of the limited effects shown in this study, and additional research is needed in this field.

Frozen cultured sheets of human epidermal keratinocytes enhance healing of full-thickness wounds in mice.

Sheets of cultured allogeneic human keratinocytes have been used for the treatment of burns and chronic leg ulcers but there has been no animal assay for the therapeutic action of these cultures. In order to analyze the effects of frozen cultures of human keratinocytes on wound healing, we have developed such an assay based on the rate of repair of full-thickness skin wounds in immunocompetent NMR1 mice. Reepithelialization of the control wounds, originating from the murine epithelium at the edge of the wound, occurred at a constant rate of advance of 150 microm/day. When frozen cultured human epidermal sheets were thawed at room temperature for 5-10 min and applied to the surface of the wound, the murine epithelium advanced at 267 microm/day. Most wounds treated with frozen cultures completely healed after 10 days, whereas most control wounds required 16 days. The accelerated reepithelialization did not depend on the presence of proliferative human keratinocytes in the frozen cultures. The cultures also promoted early formation of granulation tissue and laminin deposition over the surface of the wound bed. This simple assay should permit quantitative analysis of the effects on healing exerted not only by cultured cells, but also by proteins and small molecules.

[Electrosurgery as treatment of high grade squamous intraepithelial lesions of the cervix]. / Electrocirugía como tratamiento de las lesiones intraepiteliales escamosas de alto grado del cérvix.

A prospective study was realized with the purpose of evaluating the efficiency of the excisional therapy of the electrosurgery in the treatment of the High Grade Squamous Intraepithelial Lesion (H.G.S.L.I.) of the cervix. 149 patients who were attended at the colposcopy service with this diagnosis were selected during September 1990 to April 1993. The procedure was realized in 37 patients 24.8% in the operating room and in 112 patients (75.2% in the outpatient room with local anaesthesia. With this last mentioned method in 93.8% not one type of trouble was presented, referring only a slightly to moderate pain in 6.2%. The transoperatory complications were bleeding on the surgical site in 3.3% which was solved at the moment through local electrocoagulation, and late bleeding present in 4.2% of the patients. The lesion was completely eliminated when the deepness of the cone corresponded to 1.81 cm in 139 cases (93.29%). Through a colpo-cytologic follow-up in 24 months, a persistence of the virus of the human papilloma was shown in 5.5% during the first nine months and appearance of one case of H.G.S.I.L. after 18 months. Therefore, these results had a therapeutic efficiency of the global follow-up of 90.08%.