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G Montes de Oca

Publications and source records attributed to G Montes de Oca.

5 recordsLinked to original sources
PubMed1997

Myosin I interactions with actin filaments and trans-Golgi-derived vesicles in MDCK cell monolayers.

In MDCK cell cultured monolayers, as well as in natural and other cultured epithelia, the proper organization of the actin filament ring, tethered to the plasma membrane at the zonula adhaerens, is apparently necessary for their functioning as a transporting epithelium. It has been proposed that actin filaments, in conjunction with motor proteins, could provide the structural basis that regulates the tight junction (TJ) sealing capacity as well as the transport of membrane-tagged proteins required for cell polarization. To test this hypothesis, the authors analyzed the localization and possible association of the actin-binding motor protein myosin I with actin filaments during changes in the actin ring position and organization, and also with trans-Golgi-derived vesicles. Modifications of the ring were induced subjecting the cells to external Ca2+ depletion and restoration (Ca2+ switch), or by treatment with drugs known to depolymerize actin filaments (cytochalasin D, CD). The distribution of myosin I and actin, both in intact cells and in cellular fractions, was monitored using heterologous cross-reacting antibodies and phalloidin. The authors identified an isoform of myosin I of approximately 110-125 KDa, homologous to myosin IB of Acanthamoeba, a fraction of which colocalized with the peripheral actin ring. The association seems transient as, once the ring retracted as result of Ca2+ depletion, or became disorganized by CD, myosin not longer colocalized with the actin fibers but appeared dispersed in the cytoplasm. Furthermore, a significant fraction of the total myosin I in the cell was associated to Golgi-derived vesicles which could also associate in vitro with actin filaments. The authors' data support, then, the participation of myosin I, in association with actin filaments, in vesicle translocation to and from the cell membrane as proposed for natural epithelia, and provide a further insight into the structural organization that maintains epithelial cell polarity in cultured monolayers.

Actin Cytoskeleton↗
PubMed1992

Treatment of type I diabetes with a combination of glyburide and insulin.

OBJECTIVE: To assess the ability of a combination of insulin and an oral hypoglycemic agent (glyburide) to improve the overall glycemic control in a population of patients with type I diabetes. DESIGN: Randomized, placebo-controlled, double-blind trial. SETTING: Community-based, university-affiliated, family medicine group. PATIENTS: Men and women between 18 and 68 years of age with type I diabetes. INTERVENTIONS: Subjects were observed and titrated on an insulin-only regimen for 12 weeks (phase I). Subjects were then randomized to receive either placebo or glyburide 10 mg/d for an additional 12 weeks (phase II). MAIN OUTCOME MEASURES: Glucose measurements were taken at breakfast, lunch, supper, and bedtime. Each patient also was followed sequentially for serum lipids, glycosylated hemoglobin, (Hb A1c) and daily insulin utilization. RESULTS: Average fasting blood glucose (FBG) measurements were significantly lower in the glyburide-treated group during phase II (9.22 +/- 0.55 mmol/L) compared with baseline (10.27 +/- 0.93 mmol/L) and phase I (10.41 +/- 0.55 mmol/L). A decrease in the average Hb A1c concentration in the glyburide group was evident by week 4 and was sustained for the duration of the study. The average daily insulin dose rose significantly in the glyburide but not the placebo group compared with baseline. Total cholesterol, triglycerides, and low-density lipoprotein cholesterol did not change significantly in either group over the course of the study. High-density lipoprotein cholesterol increased significantly over baseline in the glyburide group during phase II. Several patients experienced dramatic improvements in glycemic parameters after the addition of glyburide to their insulin regimens. CONCLUSIONS: Improvements were observed in the FBG and Hb A1c measurements of this heterogeneous population of patients with type I diabetes after the addition of glyburide to their insulin regimens. The study failed to find consistent trends in glycemic control when evaluating mean changes in FBG measurements.

Adolescent↗
PubMed1990

Use of cultured human epidermal keratinocytes for allografting burns and conditions for temporary banking of the cultured allografts.

Five children who suffered burns clinically regarded as full skin thickness loss were grafted with cultured allogeneic skin from newborn prepuce. The wounds had remained open and infected without healing for about 20 days before the patients were received in the burn unit. To avoid losing surviving deep epidermal cells the wounds were débrided but not deeply excised and, a few days before allografting, they were washed with isodine solution and sterile water, and treated with silvadene cream application. All children received 76 cultured allografts of about 60 cm2 each. After allografting, the wounds were epithelized in 7-10 days and the allogeneic grafted skin began desquamation suggesting that the allograft did not 'take' permanently but was replaced by the newly formed skin. On the other hand, since allografting is an adequate therapy to provide early temporary coverage in extensively burned patients, we developed conditions for banking cultured skin to make it available for immediate use. The conditions described allow banking of the cultured grafts for 15-20 days with retention of clonal growth ability similar to that of unstored epithelia. The results show that cultured epidermal cells obtained from human newborn foreskin, when used as allografts for coverage of full skin or deep partial skin thickness burns, allow rapid epithelization of the burn wounds.

Burns↗