Determination of the Culture Time Point to Induce Corneal Epithelial Differentiation in Induced Pluripotent Stem Cells.

BACKGROUND: Limbal stem cells (LSC) are progenitor cells in the ocular surface that renew the corneal epithelium. Limbal stem cell deficiency usually induces blindness through the loss of corneal transparency, and bilateral cases do not an accurate treatment because of the lack of an autologous source of stem cells. METHODS: Induced pluripotent stem cells (iPSC) are promising for use in cell therapy because of their autologous origin and the capability to differentiate into corneal epithelial cells. However, there are not standardized protocols to achieve a complete corneal epithelial differentiation. We examined the expression of several markers in a human episomal iPSC line after an induction period from embryoid bodies. RESULTS: Progenitor LSC and corneal epithelial differentiation markers, some extracellular matrix protein adhesion molecules, and wingless signaling pathway were studied. Overall, LSC progenitor and corneal epithelium differentiation markers increased after maintaining cell culture in specific conditions for 14 days, whereas pluripotency markers decreased. CONCLUSIONS: Our approach indicated that the optimal time point to initiate iPSC differentiation into LSC and corneal phenotypes, with the use of specific medium, is from 14 days after initial embryoid bodies treatment induction.

Laparoscopic Roux-en-Y gastric bypass: a totally intra-abdominal approach--technique and preliminary report.

BACKGROUND: Previous descriptions of a laparoscopic Roux-en-Y gastric bypass, using a circular stapler to perform the gastrojejunal anastomosis, have employed the esophagus as a conduit to introduce the anvil of the stapling device into the stomach. The authors believe that the risk of injury to the esophagus, as well as the difficulty in maneuvering the anvil from the pharynx to the proximal part of the stomach, make this technique less than optimal. In other descriptions (in a porcine model) the anvil has been guided into position through a distal gastrotomy by attaching it to a Prolene suture on a straight needle and directing the needle toward a chosen site. Although the authors prefer this method because it avoids potential esophageal injury, they sought a technique that would be even more precise in anvil placement and would avoid pushing a needle across gastric mucosa. METHODS: The authors have developed a method that is totally intra-abdominal and does not risk injury to the esophagus. The circular stapler is still used, thus giving a consistent, small opening through the gastrojejunal anastomosis. RESULTS: Over a 1-year period, 49 (of 50) patients underwent laparoscopic Roux-en-Y gastric bypass with the described method. The average body mass index dropped from 42.63 to 34.12 over the first postoperative 3 months, with an average loss in excess body weight of 38.5%. The length of hospitalization following the procedure averaged 3.8 days, and the time to return to work (where applicable) was 11.9 days. CONCLUSION: This totally intra-abdominal laparoscopic technique is feasible and advantageous.

Balloon dissection of the space of Bogros via the femoral canal for total extraperitoneal laparoscopic herniorrhaphy.

To obviate the need for general anesthesia or dissection of the rectus sheath, we have transferred laparoscopic herniorrhaphy back to the groin by first dissecting the suprainguinal parietoperitoneal space of Bogros via the femoral canal. Cadaver dissections demonstrated that the preperitoneal plane could be routinely fingered and distended with a digitally placed balloon introduced through a 1-cm incision immediately below the inguinal ligament. A 10-mm femoral laparoscopic port was then inserted and pressurized, allowing two standard 5-mm ports to be introduced from above, through the lower quadrant, under vision. The procedure was then carried out in the usual way, the mesh being inserted from below. Ten patients (two women), 23-73 years old, selected because general anesthesia was inadvisable, underwent uncomplicated prosthetic repair of unilateral (eight) or bilateral (two) inguinal defects. Half of the peritoneal sacs were pushed up and out of the inguinal canal; 18 months later there were no recurrences (inguinal or femoral). Preliminary experience with this new technique is promising. It may prove applicable to retroperitoneal exposure of the distal aorta and iliac vessels, allowing laparoscopic bypass for Leriche syndrome.

Advances in balloon dissection.

The use of a balloon as a dissecting tool was pioneered by Gauer and Kieturakis in the early 1990s.This newapplication of balloon dissection in surgery allows the creation of a working space in which a procedure is performed. This is combined with minimally invasive techniques that confer the advantages of shorter recovery and less pain for several different procedures.

Screening of medicinal plants for induction of somatic segregation activity in Aspergillus nidulans.

Knowledge about mutagenic properties of plants commonly used in traditional medicine is limited. A screening for genotoxic activity was carried out in aqueous or alcoholic extracts prepared from 13 medicinal plants widely used as folk medicine in Cuba: Lepidium virginicum L. (Brassicaceae): Plantago major L. and Plantago lanceolata L. (Plantaginaceae); Ortosiphon aristatus Blume, Mentha x piperita L., Melissa officinalis L. and Plectranthus amboinicus (Lour.) Spreng. (Lamiaceae); Cymbopogon citratus (DC.) Stapf (Poaceae); Passiflora incarnata L. (Passifloraceae); Zingiber officinale Roscoe (Zingiberaceae); Piper auritum HBK. (Piperaceae); Schinus terebinthifolius Raddi (Anacardeaceae) and Momordica charantia L. (Cucurbitaceae). A plate incorporation assay with Aspergillus nidulans was employed, allowing detection of somatic segregation as a result of mitotic crossing-over, chromosome malsegregation or clastogenic effects. Aspergillus nidulans D-30, a well-marked strain carrying four recessive mutations for conidial color in heterozygosity, which permitted the direct visual detection of segregants, was used throughout this study. As a result, only in the aqueous extract of one of the plants screened (Momordica charantia) a statistical significant increase in the frequency of segregant sectors per colony was observed, and consequently, a genotoxic effect is postulated.

Bacterial mutagens in the urine of patients under tinidazole treatment.

Tinidazole is an antiparasitic drug belonging to the 5-nitroimidazole family. It is prescribed against protozoal infestations and is widely used in Mexico as well as other underdeveloped countries where infectious diseases are the first cause of children mortality. The drug is a direct mutagen in Salmonella typhimurium TA100 strain and the presence of S9 mixture did not modify its mutagenic effect. At low doses no mutagenicity was detected with strains TA100NR, TA98 or UTH8414 (Uvr+ derivative of TA100). Urine from four patients under tinidazole treatment exhibited a mutagenic activity on strain TA100, greater than the expected from the tinidazole concentrations determined by high-performance liquid chromatography (HPLC). Components from the urine samples were separated on thin-layer chromatography (TLC) plates, and their mutagenic effects tested by direct application of the Salmonella assay onto sections of the developed chromatoplate. The Rf of one component (0.62) corresponded to the one obtained for a tinidazole standard and showed the expected mutagenicity, while a second component with an Rf=0.39, exhibited a mutagenic potency slightly greater than the observed for tinidazole; however, as in the case of the drug itself, reduction of the nitro group was necessary for a mutagenic activity.

Management of intraabdominal testicle during laparoscopic hernia repair.

A 22-year-old man who had previously undergone work-up for right cryptorchidism and been diagnosed as having right testicular absence was referred for repair of a right inguinal hernia. A laparoscopic approach was chosen for this patient, and at the time of laparoscopic herniorrhaphy, a small intraabdominal testicle was visualized and removed laparoscopically. Laparoscopy has served as an excellent procedure for locating intraabdominal testes and planning the most appropriate treatment for many cryptorchid patients. Until recently, atrophic testes located within the abdominal cavity through use of a laparoscope were removed via an open technique. Advances in laparoscopy now enable detection and definitive treatment for these patients without the need for large, more painful incisions. The laparoscopic approach to this patient enabled diagnosis and management of his cryptorchidism and provided a means for repair of his hernia.

Genotoxic activity of mebendazole in Aspergillus nidulans.

Mebendazole is an anthelmintic drug widely used in Cuba and in Mexico. Its interaction with tubulin interferes with the assemblage of the mitotic apparatus in the parasite cells, thus suggesting a possible genotoxic activity leading to chromosomal malsegregation. The heterozygous diploid strain D30 of Aspergillus nidulans was used to establish the ability of mebendazole to induce mitotic recombination and/or chromosomal non-disjunction, and the haploid strain FGSC #219 of A. nidulans was used to study the ability of mebendazole to induce point mutations in the methG suppressor system. Our results show that mebendazole can induce chromosomal non-disjunction but it fails to promote point mutations.

Comparison of operative versus percutaneous endoscopic gastrostomy tube placement in the elderly.

To compare techniques of gastrostomy in elderly patients, the records of 100 patients age 70 and older who underwent gastrostomy tube placement as a primary procedure were reviewed. Two separate unmatched groups of 50 patients each were identified: those that underwent operative gastrostomy tube (OGT) placement and those that underwent percutaneous endoscopic gastrostomy tube (PEG) placement. The groups were studied for demographic similarities and for differences in morbidity, mortality, and ease of feeding. Comparison showed that PEGs had a lower mortality (0%) and morbidity (10%) than did OGTs where mortality was 4 per cent and morbidity was 22 per cent. PEGs began feeding sooner (1.0 day vs. 2.8 days) than OGTs. In addition, almost 60 per cent of the PEG patients underwent complete upper endoscopy at the time of the PEG, which revealed pathology that either altered the type of tube placed or the eventual medical management. PEG offers a less morbid, safer, and easier to use method of gastrostomy tube placement than OGT in the majority of elderly patients.

Percutaneous endoscopic jejunostomy in a patient with previous esophagectomy.

Establishment of a percutaneous endoscopic jejunostomy via direct jejunal puncture was accomplished in a 45-year-old woman five years after a partial esophagectomy with cervical esophagogastrostomy for adenocarcinoma of the esophagus. The patient had recurrence of the cancer at the anastomotic site with subsequent inability to eat, necessitating a feeding tube for prolonged enteral nutrition. Although percutaneous puncture of the jejunum has been previously described, it has been limited to patients who had undergone partial or complete gastrectomies with Bilroth II anastomoses. This case report of direct endoscopic jejunal tube placement in a patient after esophagectomy further establishes this procedure as a viable alternative to surgically placed feeding tubes in patients with altered gastric anatomy.

Genotoxic effects of niclosamide in Aspergillus nidulans.

A 2-5-month treatment with niclosamide, a widely used drug in developing countries, has been reported to induce lymphosarcomas in toad liver and kidney. The genotoxic effects of this drug have also been evaluated in Salmonella typhimurium, in somatic and germinal cells of mice and in human lymphocytes exposed in vitro and in vivo. The present study shows that niclosamide is also capable of inducing mitotic crossing-over and non-disjunction in Aspergillus nidulans, which points to the wide potential of this drug as a genotoxic agent.