Mental Health and Physical Activity among Children and Adolescents during the COVID-19 Pandemic

Coronavirus disease 2019 (COVID-19) is causing disruptions in the global social system. Japanese children and adolescents have had their schools closed, government-mandated activity restrictions imposed, and interactions outside the home reduced. These restrictions can have a considerable psychological impact on children and adolescents. This review aims to describe the impacts of COVID-19 pandemic on physical activity and psychological status of this population. The review was conducted by searching PubMed for information on the impact of COVID-19-related activity restrictions on children and adolescents. The search identified 11 articles, three of which contained data on anxiety and psychological problems due to physical inactivity. Next, a PubMed search was conducted about physical activity and psychological status in children and adolescents under psychological stress. The search identified 368 articles, 28 of which were included in the review. For children, data that revealed a correlation between physical activity and psychological health and sedentary time leading to mood disorders were included. For adolescents, there were nine studies that reported a correlation between physical activity and psychological health and four studies that reported no correlation between physical activity and psychological health. Of the studies that reported a correlation, seven reported that physical activity improves psychological health. The impact of psychologically stressful situations such as COVID-19 on children and adolescents has been experienced worldwide. Physical activity has been correlated with psychological health, and it may improve psychological status; physical activity should be recommended to better support the psychological health of children and adolescents under the influence of COVID-19.

Ethanol lock therapy in pediatric patients: A multicenter prospective study

BACKGROUND

Ethanol lock therapy (ELT) has been performed for the purpose of preserving central venous catheters (CVC) in central venous catheter-related blood stream infection (CRBSI), but evidence for its effectiveness is not established. We conducted a multicenter, prospective study on the ELT protocol to ascertain its safety and effectiveness against CRBSI.

METHODS

The subjects were patients aged over 1 year with potential for developing CRBSI who had long-term indwelling silicone CVCs. After culturing the catheterized blood, a 70% ethanol lock was performed daily for 2-4 h for 7 days. The effectiveness rate of ELT for single and multiple courses, the presence or absence of relapse of CRBSI within 4 weeks of treatment, and whether the CVC could be salvaged after 4 weeks were examined.

RESULTS

From September 2014 to August 2018, 49 cases from six hospitals were enrolled in the study. Catheter blockage was seen in one case and the CVC was removed. A single course of ELT was effective in episodes 88% (42/48). In the remaining three episodes that failed after a single course of ELT, a second ELT was performed; however, all were ineffective. In episodes 93% (40/42), no CRBSI relapse was seen up to 4 weeks after the end of treatment. In episodes 84% (41/49), the catheter could be preserved for 4 weeks or more after the end of treatment. Facial flushing was seen in two cases as an adverse event; however, this was transient and soon disappeared.

CONCLUSION

ELT is effective for 88% of CRBSI and 84% of catheters can be salvaged; therefore, this protocol is considered useful.

TRIAL REGISTRATION

UMIN000013677.

Timing and outcome of stoma closure in very low birth weight infants with surgical intestinal disorders

PURPOSE

Very low birth weight infants (VLBWIs) are at risk of surgical intestinal disorders including necrotizing enterocolitis (NEC), focal intestinal perforation (FIP), and meconium-related ileus (MRI). We conducted this study to verify whether the timing of stoma closure and that of enteral nutrition establishment after stoma closure in VLBWIs differ among the most common disorders.

METHODS

A retrospective multicenter study was conducted at 11 institutes. We reviewed the timing of stoma closure and enteral nutrition establishment in VLBWIs who underwent stoma creation for intestinal disorders.

RESULTS

We reviewed the medical records of 73 infants: 21 with NEC, 24 with FIP, and 25 with MRI. The postnatal age at stoma closure was 107 (28-359) days for NEC, 97 (25-302) days for FIP, and 101 (15-264) days for MRI (p = 0.793), and the postnatal age at establishment of enteral nutrition was 129 (42-381) days for NEC, 117 (41-325) days for FIP, and 128 (25-308) days for MRI (p = 0.855). The body weights at stoma closure were 1768 (620-3869) g for NEC, 1669 (1100-3040) g for FIP, and 1632 (940-3776) g (p = 0.614) for MRI. There were no significant differences among the three groups.

CONCLUSIONS

The present study revealed that the time and body weights at stoma closure and the postoperative restoration of bowel function in VLBWIs did not differ among the three diseases.

The possibility of muscle tissue reconstruction using shape memory alloys

Severe dysfunction of muscle tissues can be treated by transplantation but the success rate is still not high enough. One possibility instead is to replace the dysfunctional muscle with artificial muscles. This article introduces a unique approach using shape memory alloys (SMAs) to replace the anal sphincter muscle for solving the problem of fecal incontinence. The use of SMAs that exhibit a two-way shape memory effect allows the device to function like a sphincter muscle and facilitates simple design. In this article, we will give a brief introduction to the functional material-SMA-together with its medical applications, and will follow this with a description of the recent progress in research and development of an SMA-based artificial sphincter. The possibility of its commercialization will also be discussed.

Posttraumatic stress disorder in mothers of children who have undergone surgery for congenital disease at a pediatric surgery department

PURPOSE

The aim of the study was to investigate posttraumatic stress disorder (PTSD) in mothers of children who have undergone surgery for congenital disease at a pediatric surgery department.

METHODS

A questionnaire survey was carried out in 145 mothers of children who had undergone surgery and were still alive. For comparison, the mothers were categorized into 3 groups according to the severity of their child's disease.

RESULTS

Of the 145 mothers, 29 (20%) were likely to be diagnosed as having developed PTSD at the time of the survey. Posttraumatic stress disorder symptoms correlated with factors such as anxiety and condition of the child. In terms of the disease severity of the child, factors such as anxiety tended to be observed more frequently in the higher disease severity group, whereas the proportion of mothers likely to be diagnosed as having developed PTSD was smallest in the moderate-severity group.

CONCLUSIONS

Twenty percent of the mothers of children had probably developed PTSD. In the moderate-severity group, there seemed to be a factor that alleviated PTSD symptoms. Because mothers provided effective care for the symptoms of children in the moderate-severity group, this observation suggests that participation of the mother in their child's treatment might prevent them from developing PTSD symptoms.

Postoperative psychological status of children with anorectal malformations

Our purpose was to clarify factors that influence the level of depression of Japanese children with anorectal malformations (ARM). The subjects comprised 66 children with ARM, aged 0-16 years, and their mothers. Patients were divided into three groups (Group 1: aged 0-5 years, Group 2: 6-11 years, and Group 3: 12-16 years). The level of depression of the children aged 6-16 years was investigated by Kovac's children's depression inventory (CDI). The psychological status of their mothers was assessed by Spielberger's state-trait anxiety index (STAI) and Zung's self-rating depression scale (SDS). The classification of ARM and the clinical condition were also investigated. Defecation scores were assigned for the degree of bowel dysfunction. The level of depression in the patients was more marked in Group 3 than in Group 2 according to the CDI score. Significant correlations between the CDI score of the child and the STAI-1, STAI-2 and SDS scores of the mother were observed in Group 2, but not in Group 3. In Group 2, the STAI-1 score of the mothers was significantly influenced by the degree of bowel dysfunction in her child. In Group 3, the CDI score was significantly correlated with the constipation score. This study revealed that bowel dysfunction is the important factor that influences the level of depression of the children with ARM. In the period of childhood during which the child attends primary school, bowel dysfunction indirectly influences the level of depression of children through the psychological status of mothers. However, bowel dysfunction directly influences the level of depression of children in adolescent patients.

Preclinical development of SMA artificial anal sphincters

This article presents some progress in the development for preclinical trials of an artificial anal sphincter using shape memory alloys. The novel device has been proposed and developed by the author's group at Tohoku University. It has two dominant features different from other systems, which are either clinically available or still under development. One is that a solid driving element, a combination of shape memory alloy (SMA) ribbons and silicone elastomer sheets with a layered structure, is adopted for the opening and closing functions of the artificial sphincter. The other is a sandwich mechanism for the closing of bowel to reduce the risk of buckling induced ischemia which has been reported in hydraulically driven artificial sphincters with a radial squeezing mechanism. The device has fewer parts inside the body and therefore be implanted more easily. A new design eliminating the risk of heat burns enables long-term implantation and brings the device closer to practical use. Functionality and safety of the device have been proved in three-month animal experiments.

Two Cases of Living-Related Intestinal Transplantation

We recently performed living-related small bowel transplant in two patients. The first patient was a 14-year-old boy with total parenteral nutrition (TPN)-dependent short-bowel syndrome associated with hypoganglionosis. He received a bowel graft from his 43-year-old mother. The second patient was a 27-year-old female who had undergone massive enterectomy due to volvulus. She underwent living-related bowel transplantation from her 57-year-old mother. In both cases, blood types were ABO identical, cytotoxic cross matches were negative, and cytomegalovirus status was positive to positive in both cases. Up to one third of the donor bowel was harvested from the distal ileum. The graft vessels were connected to infrarenal aorta and inferior vena cava. The immunosuppressive regimen consisted of daclizumab, tacrolimus, and steroids. The first patient developed progressive acute cellular rejection on postoperative day 9, requiring OKT-3 therapy. Two months after transplantation, he was weaned off TPN, tolerating oral intake with a fully functioning graft. The second patient was weaned off TPN on day 29 with a functioning graft. Her metabolic disorder dramatically improved. This patient developed indeterminate acute cellular rejection on day 111, which was successfully treated with bolus injections of steroid. Both donors had no complications; they were discharged on day 10. Living-related intestinal transplantation can be a treatment option for patients with short-bowel syndrome.

Living-related intestinal transplantation for a patient with hypoganglionosis

A 14-yr-old boy with total parenteral nutrition-dependent short-bowel syndrome associated with hypoganglionosis underwent the LR-IT by using a 150 cm segment of distal ileum taken from a healthy donor. The graft vessels were connected to infrarenal aorta and inferior vena cava. The immunosuppressive regimen consisted of daclizumab, tacrolimus, and steroid. The graft surveillance for ACR was accomplished using zoom endoscopy and mucosal biopsy. The blood trough level of tacrolimus was maintained between 20 and 25 ng/mL for the first 2 months, followed by 15-20 ng/mL thereafter. The 50 mg of daclizumab was administered on the day of operation, and same dosage was repeated at 2-wk intervals. The first ACR occurred on POD-9 and was progressive, and required a 14-day course of OKT-3 injection. After the treatment with OKT-3, the graft recovered from the ACR, and began to function well enough to discontinue the intravenous nutrition on POD-55. No infectious complication has occurred. The patient was discharged in POD-112, and currently tolerates full oral intake without requiring intravenous nutritional or fluid supplementation. The donor was discharged without any complications. The LR-IT could successfully be performed with minimal risk to the donor, and it can be a treatment of choice for patients with short-gut syndrome associated with hypoganglionosis.

Psychosocial liaison-consultation for the children who have undergone repair of imperforate anus and Hirschsprung disease

OBJECTIVE

The aim of this study was to investigate the psychological status of Japanese children with congenital anorectal malformation and their mothers to develop appropriate psychiatric interventions.

METHOD

The subjects comprised 50 children with congenital anorectal malformation aged 0 to 16 years and their mothers. The psychology of children aged 7 to 16 years was investigated by Kovacs' Children's Depression Inventory (CDI). The psychology of their mothers was assessed by Spielberger's State-Trait Anxiety Index (STAI) and Zung's Self-rating Depression Scale (SDS).

RESULTS

Depression was more marked in the children aged 12 to 16 years than in those aged 7 to 11 years according to the CDI. The mothers of preschool children showed higher levels of anxiety and depression than those of school-aged children, according to the STAI and SDS. Significant correlations between the CDI score of the children and the STAI or SDS score of the mothers were observed only among children aged 7 to 11 years.

CONCLUSIONS

The frequency of depression and anxiety among children with congenital anorectal malformation and that among their mothers was associated with the age of the child. Long-term postoperative psychosocial support for the children and their mothers may be required, taking into account the age of the child.

Living-Related Small Bowel Transplantation: Two Cases Experiences

We have recently performed living-related small bowel transplantation for 2 patients. The first patient was a 14-year-old boy with total parenteral nutrition (TPN)-dependent short-bowel syndrome associated with hypoganglionosis of the entire intestine. He received a bowel graft from his 43-year-old mother. The second patient was a 27-year-old woman, who had massive enterectomy due to volvulus and developed vitamin deficiencies and severe metabolic disorders as a result of long-term TPN. She underwent living-related bowel transplantation from her 57-year-old mother. Blood types were ABO identical, cytotoxic cross matches were negative, and cytomegalovirus statuses were positive-to-positive in both cases. Up to one third of the donor bowel was harvested from the donor distal ileum more than 30 cm away from the ileocecal valve. The graft vessels were connected to infrarenal aorta, and inferior vena cava. The immunosuppressive regimen consisted of daclizumab, tacrolimus, and steroid. The graft surveillance was accomplished using zoom endoscopy and mucosal biopsy. The first patient developed progressive acute cellular rejection (ACR) on the 9th postoperative day (POD)-9 requiring OKT-3 therapy, which was effective. Two months after transplantation, he was weaned from TPN, tolerating oral intake with a fully functioning graft. The second patient experienced no episode of ACR and was weaned off TPN on POD-29 with a functioning graft. Her metabolic disorder dramatically improved after bowel transplantation. Both donors had no complication and were discharged from the hospital on POD-10. Living-related bowel transplantation is an extreme option of treatment for patients with short-bowel syndrome.

Thoracoscopic Removal of Neurogenic Mediastinal Tumors in Children

PURPOSE

The aim of this study was to evaluate the feasibility and advantages of thoracoscopic removal of neurogenic mediastinal tumors (NMTs) in children.

METHODS

From January 1998 to December 2001, 6 patients, ages 1.1 to 6.8 years (mean, 3.5 years), underwent thoracoscopic removal of NMT. A retrospective study was done to assess the type of anesthesia, conversions to standard thoracotomy, operative time, complications, and the current status of each patient.

RESULTS

General anesthesia using a Fogarty catheter as an ipsilateral bronchial blocker was utilized. Four 5-mm ports were placed in all patients. All NMTs were successfully removed without a need to convert to standard thoracotomy. The tumor was captured in an extraction bag, fragmented, and then removed through the trocar site, which had been enlarged up to 2.0-2.5 cm in each case. Pathologic diagnosis was neuroblastoma in 1 patient, ganglioneuroblastoma in 2, and ganglioneuroma in 3 patients. The mean operative time was 230 minutes. There was no need for transfusion and no serious complication related to this approach. All patients are alive at the time of writing, without any evidence of tumor recurrence.

CONCLUSION

All tumors were successfully removed. Thoracoscopic surgery is a feasible, safe, and effective technique in the treatment for children with NMT.

The colon displays an absorptive capacity of tacrolimus

PURPOSE

In our previous study, blood levels of orally administered tacrolimus were significantly higher in short bowel piglets than in control animals. It has been reported that the blood levels of tacrolimus are influenced by the metabolic activity of intestinal CYP3A4. If tacrolimus may be absorbed in the colon, direct administration of drug into this organ might be useful to augment bioavailability since the expression of CYP3A4 is low at this site. In the present study we evaluated the absorptive capacity of tacrolimus in the colon.

MATERIALS AND METHODS

Piglets were divided into four groups: groups 1 and 2 were controls (n = 11 and 3, respectively); group 3 underwent resection of the entire small intestine (n = 8); and group 4 had a catheter placed in the cecum (n = 4). In groups 1 and 3, tacrolimus was administered orally; in group 2 it was given intravenously; and in group 4 it was injected into cecum through the catheter from postoperative days 3 to 7. On day 7, blood samples were obtained for drug measurements to calculate the area under the concentration time curve (AUC) values.

RESULTS

The trough level and AUC values of tacrolimus in group 4 as well as in group 3 were significantly higher than those in group 1. In Group 4 animals showed a 60-minute time to peak concentration.

CONCLUSIONS

Tacrolimus is absorbed by the colon. Since the blood levels were not influenced by the metabolic activity in the graft bowel, direct administration of tacrolimus into the colon might be useful in small intestinal transplantation.

An experimental study on the utility of a 3-mm ultrasonically activated trocar system

BACKGROUND/PURPOSE

A prototype of a 3-mm ultrasonically activated trocar system supplied by Olympus Corporation was evaluated experimentally in terms of its utility and safety.

METHODS

Three piglets with an average weight of 12 kg were used. A pneumoperitoneum was created by Hasson's technique. Eleven punctures were made with a disposable conical 3-mm trocar (CT), 9 punctures with a 3-mm radially expanding trocar (ET), and 13 punctures with a 3-mm ultrasonically activated trocar (UT) under laparoscopic control. The authors recorded the time for abdominal penetration, the severity of the peritoneal tenting, the presence of elevated abdominal pressure of 5 mm Hg or more at the penetration, and the maximal force applied to the trocar to remove from the abdominal wall.

RESULTS

The average times for penetration were 11.8, 9.4, and 3.8 seconds with CT, ET, and UT, respectively (P < .05, CT v. UT, ET v. UT). The average maximal forces at the trocar removal were 10.52, 21.17, and 21.24 N with CT, ET, and UT, respectively (P < .05, CT v. ET, CT v. UT). Elevation of abdominal pressure of 5 mm Hg or more was recorded in CT and ET but not in UT. Peritoneal tenting was the most severe in ET and minimal in UT. No complication related to the UT system was found.

CONCLUSIONS

The 3-mm UT is a simple and safe device and is expected to become commercially available.

Functional Evaluation of an Artificial Anal Sphincter Using Shape Memory Alloys

This article describes an implantable artificial anal sphincter using shape memory alloys and its in vivo assessment in porcine models. The new design was developed as a low invasive prosthesis with a simple structure to solve the problem of severe fecal incontinence in patients with hypoplastic sphincters or without anal sphincters and especially for ostomates. The artificial anal sphincter consists of two shape memory alloy (SMA) plates as the main functional parts to perform two basic functions when the SMA artificial sphincter is fitted around intestines (i.e., an occlusion at body temperature and an opening function on heating). Our previous assessments with short-term animal experiments revealed promising properties with the occlusion function of the device, although some complications, such as overpressure induced ischemia, heat burn, and infections, remained. This article addresses the concerns related to the practical use of the device, the power supplement to drive the actuator, and overheating protection of the device inside bodies. Results of chronic animal experiments of up to 4 weeks suggested great potential for the improved device.

[Congenital esophageal atresia]

Current management of congenital esophageal atresia (CEA) is described on the basis of our experience and recent literatures. Primary repair for Gross C type CEA is performed as modern standard treatment in infants without high-risk factors such as associated severe cardiac anomaly and respiratory insufficiency. Surgical strategy depends on preoperative condition of the infant therefore preoperative full assessment of the infant is very important. In general, delayed primary repair or staged repair on CEA is selected for premature infants weighing less than 1,500 g and high-risk infants. Recently, primary repair has become an effective option in premature infants without high-risk factors. In long-gap CEA, gastrostomy and/or closure of tracheoesophageal fistula is performed initially. Esophagoesophagostomy is carried out after attempts to decrease gap length. Intraoperative esophageal elongation is required in some infants. However esophageal replacement should be selected if esophageal elongation fails is impossible due to hypogenesis of lower esophagus. Thoracoscopic primary repair was recently reported as a new optional treatment. This treatment will be able to decrease the damage on the thoracic wall. However this procedure should be adopted after very careful discussion because it is difficult to accomplish without very skillful endoscopic surgical technique.

Biliary atresia with associated complicated anorectal and urogenital malformations

We report on a girl with biliary atresia (BA) who also suffered with anorectal agenesis without fistula and complicated urogenital malformation. The outcome of patients with these severe anomalies is poor, but she has survived without liver and/or renal transplantation for more than 3 years. A careful treatment plan for each anomaly in addition to prevention of cholangitis and urinary tract infection is indispensable for managing these complicated anomalies.

The expression of intestinal CYP3A4 in the piglet model

PURPOSE

In our previous study, the blood levels of tacrolimus were higher in the short bowel and small bowel transplantation models than those in controls. Metabolism by intestinal cytochrome p450 3A4 (CYP3A4) has been reported to influence the blood level of orally administered tacrolimus. We performed immunohistochemistry to examine the localization of intestinal CYP3A4.

MATERIALS AND METHODS

Twenty-four piglets were divided into three groups: group 1 were controls (n = 11); group 2, ileal resection of 2/3 proximal small intestine (n = 5); and group 3, total small intestinal resection followed by 1/3 allotransplantation of ileum (n = 8). Tacrolimus was orally administered from postoperative days 3 to 7. On day 7, blood samplings were performed for the trough level and the calculation of area under the concentration time curve (AUC). Intestinal specimens from the jejunum, ileum, colon, and ileal graft were obtained on days 0 and 10 for immunohistochemistry of CYP3A4.

RESULTS

The trough and AUC values in group 2 were significantly higher than those in group 1. Furthermore those measurements in group 3 animals were higher than in group 2 (trough levels: 2.5 +/- 1.7, 11.2 +/- 2.1, 16.3 +/- 2.7 ng/mL and AUC values: 126 +/- 90, 319 +/- 155, 546 +/- 117 ng. h/mL). The expression levels of CYP3A4 were, jejunum > ileum > ileal graft > colon.

CONCLUSIONS

The intensity and extent of CYP3A4 staining diminished in the ileal graft showing an inverse correlation to the blood concentrations.

Development of an implantable artificial anal sphincter using a shape memory alloy

BACKGROUND/PURPOSE

The authors created a new artificial anal sphincter using a shape memory alloy (AS-SMA) to treat fecal incontinence and evaluated its validity.

METHODS

AS-SMA consists of 2 Ti-Ni plates to sandwich the intestine and generates a pressure of 55 mm Hg at its resting position. With the electric power supply, the 2 metals bend to form an almondlike shape making a maximum gap of 33 mm between each other at the temperature of 55 degrees C. The device was attached to the colostomy in a piglet and was operated several times a day for 1 month. Fecal continence, bowel movements, and general condition of the piglet were recorded. After the experiment, tissue damage around the device was investigated.

RESULTS

Fecal continence was obtained while the device was in the resting position. When it was operated, bowel movements were observed. The bowel movements to operations ratio was 82:105 (78%). During the experiment, the animal had neither abdominal distension nor vomiting. At the autopsy, there was mild inflammation and shallow burns around the device. No compression injury was detected.

CONCLUSIONS

AS-SMA achieved fecal continence of the colostomy. With reduction of the associated side effects, it would be a potential substitute for an impaired anal sphincter.

The functional roles of porcine CD80 molecule and its ability to stimulate and regulate human anti-pig cellular response

BACKGROUND

The pig is currently considered to be the most likely candidate for a xenogenic-organ source. Anti-pig human T-cell response via co-stimulatory molecules has been studied with great interest. The soluble form of porcine CD80 has recently been cloned and characterized, but the sequence of the transmembrane form has not been determined. The purpose of this study was to investigate the functional interaction between porcine CD80 and human T cells using the full-length clone of porcine CD80.

MATERIALS AND METHODS

Specific complementary DNA (cDNA) clones encoding porcine CD80 were isolated and sequenced using rapid amplification of cDNA ends-polymerase chain reaction. Polymerase chain reaction-amplified cDNA coding for the open reading frame of the porcine CD80 transmembrane form was subcloned into an expression vector and then transfected into Chinese hamster ovary (CHO) cells. CHO cells transfected with porcine CD80 (CHO-pCD80) were co-cultured with human CD4+ T cells and then interleukin-2 secretion was measured and transferred pCD80 expression in these human T cells was detected by flow cytometry.

RESULTS

We cloned and determined the complete nucleotide sequence for the transmembrane form of porcine CD80. Results from our T-cell co-stimulatory assay showed significant interleukin-2 production when co-stimulated with CHO-pCD80. Human naïve CD4+ T cells acquired xenogenic pCD80 molecules in the process of T-cell activation.

CONCLUSIONS

Findings from this study seem to suggest that pCD80 has the functional ability to regulate human anti-pig cellular response. In addition, genetic manipulation of porcine co-stimulatory molecules offers a potentially new therapeutic strategy to prevent xenogeneic rejection across species.

Clinical characteristics and management of congenital esophageal stenosis: a report on 14 cases

PURPOSE

The aim of this study was to review 14 patients with congenital esophageal stenosis (CES) from diagnostic and therapeutic points of view.

METHODS

From 1976 to 1999, 14 patients with CES were treated at the authors' hospital. In each diagnostic examination, an esophagogram, 24-hour pH monitoring, a manometric study, and an endoscopy were performed. The medical, radiologic, and operative reports of these patients were reviewed.

RESULTS

Esophagogram results showed an abrupt stenosis in 5 patients and a tapered stenosis in 9. After 24-hour pH monitoring and an endoscopy, we were able to rule out the possibility of gastroesophageal reflux with esophagitis in most of the patients. Of the 11 patients who initially underwent bougienage or balloon dilatation, 8 of them had recurrent stenosis. Eleven patients required surgical treatment, including the 8 who had recurrent stenosis after undergoing dilatation. Nine of the patients underwent a resection of the stenotic segment and esophago-esophagostomy. An antireflux procedure was performed on 2 patients. Another patient had an esophageal rupture, which required a jejunal interposition. A histopathologic study showed that tracheobronchial remnants were present in 6 patients, and fibromuscular thickening was found in 4 patients.

CONCLUSIONS

The efficacy of dilatation seems to be limited and may even result in severe complications such as an esophageal rupture. In this study, most patients ultimately required surgical treatment. Surgical repair for CES is the authors' preferred treatment, although initial dilatation may be effective for some patients.

High trough levels of oral FK506 induced by loss of small intestine

To establish a safe and effective usage of oral tacrolimus (FK506) in small bowel transplantation (SBTx) recipients, trough levels and area under the curve (AUC) values of FK506 were assessed using swine models of SBTx and short bowel. Thirty-eight Landrace male piglets were divided into four groups as follows: Group 1, controls (n=13); Group 2, a one-third small bowel model (n=5); Group 3, a short bowel model (n=10); and Group 4, a one-third small bowel allograft model (n=10; five donors and five recipients). Piglets of Groups 1 and 3 were further divided into two sub-groups, according to the route of drug administration: Groups 1a (n=10) and 3a (n=7) received FK506 orally, and Groups 1b (n=3) and 3b (n=3) received FK506 intravenously. Oral or intravenous FK506 was started on post-operative day 3 and continued until day 7 in each group. On day 7, trough levels and AUC values were measured. In Groups 1a, 2, 3a and 4, trough levels of FK506 were 2.1+/-1.2 (p<0.01 vs. Group 2, 3a or 4), 11.2+/-2.1, 23.3+/-4.8 (p<0.05 vs. Group 2 or 4) and 14.6+/-3.0 ng/mL, and AUC values were 101+/-90 (p<0.01 vs. Group 3a or 4), 319&+/-155, 808+/-200, and 531+/-113 ng.h/mL, respectively. Both trough levels and AUC values were lowest in Group 1a and highest in Group 3a. Between Groups 1b and 3b, there was no significant difference in the blood levels of intravenous FK506. The shorter the functioning residual small intestine was, the higher the trough level of oral FK506 was, while the presence or absence of small intestine did not affect blood levels of intravenous FK506. These results suggest that oral FK506 is metabolized in the functioning small intestine during its absorption. Therefore, events which cause intestinal malfunction, such as graft rejection in SBTx, inflammation and loss of small intestine, may adversely raise the trough level of oral FK506.

Development of an implantable artificial anal sphincter by the use of the shape memory alloy

In this study, we developed and assessed an artificial anal sphincter driven by an shape memory alloy actuator (AS-SMA). The performance characteristics of the device were analyzed with a measurement system. Assessment showed that the AS-SMA could generate a pressure of 55 mm Hg at an atmospheric temperature of 36 degrees C, and displacement of the SMA actuator was 7.5 mm when the temperature of the SMA plate was 55 degrees C. To evaluate opening and closing, we studied a piglet colostomy model, in which the AS-SMA was implanted around the colostomy in the extraperitoneal space. Flow control tests using living porcine intestine revealed that the AS-SMA could maintain fecal continence against an intestinal pressure of 75 mm Hg. The high pressure zone corresponding to the location of the device was demonstrated in a manometric examination. For 6 days after surgery, we activated the AS-SMA twice a day and observed the bowel movements. The animal experiment indicated that the AS-SMA is able to control the bowel movements of patients with fecal incontinence if several problems, such as burning of tissue around the device and compression injury of the intestine, are resolved.

Regulation of pigment cell-specific gene expression by MITF

Melanocyte and retinal pigment epithelium (RPE) specifically express tyrosinase and other melanin-producing enzymes. Microphthalmia-associated transcription factor (Mitf), encoded at the mouse microphthalmia locus, regulates the development and survival of many cell types, including melanocyte and RPE. MITF, the human homolog of Mitf, consists of at least four isoforms with distinct amino-termini, referred to as A, MITF-C, MITF-H, and MITF-M. MITF-M is exclusively expressed in melanocytes and melanoma cells, and thus represents the melanocyte lineage-specific isoform. In contrast, other isoforms are expressed in many cell types so far examined. These isoforms appear to function as transcriptional activators of the melanogenesis genes, as assessed by transient transfection assays in cultured cells. Functional significance of Mitf-M in melanocyte differentiation was verified by the molecular lesion of black-eyed white Mitf(mi-bw) mice, which lack melanocytes but have normal RPE. The Mitf gene of this mutant has the insertion of an L1 retrotransposable element in the intron between exon 3 and exon 4, leading to complete repression of Mitf-M mRNA expression. Taken together, these results suggest that melanogenesis in melanocyte and RPE is regulated by separate Mitf/MITF isoforms. Recent findings on the multiplicity of MITF isoforms are summarized.

Identification of a composite enhancer of the human tyrosinase-related protein 2/DOPAchrome tautomerase gene

The human tyrosinase-related protein 2 (TRP-2) gene promoter contains a cis-regulatory element (positions -447 to -416), termed DOPAchrome tautomerase distal enhancer 1 (DDE1). DDE1 functions as an enhancer in cultured melanoma cells and its core element includes a potential binding site for transcription factors containing a high-mobility-group domain. This core element is bound in vitro by multiple nuclear proteins, which are preferentially expressed in melanoma cells. DDE1 represents a composite enhancer that may be involved in melanocyte-specific transcription of the human TRP-2 gene.

Structural organization of the human microphthalmia-associated transcription factor gene containing four alternative promoters

Microphthalmia-associated transcription factor (MITF) affects the development of many types of cells, including melanocytes and retinal pigment epithelium (RPE). MITF consists of at least three isoforms, MITF-A, MITF-H and MITF-M, differing at their amino-termini and expression patterns. Here, we characterize the structural organization of the human MITF gene. The gene contains at least four isoform-specific first exons, exons 1A, 1H, 1B and 1M in the 5' to 3' direction, each of which encodes the unique amino-terminus of a given isoform, including newly identified MITF-B. The 5'-flanking regions of these isoform-specific exons are termed promoters A, H, B and M, respectively, which showed different promoter activities, as judged by transient transfection assay. Promoter A directs the expression of a reporter gene in RPE, cervical cancer and melanoma cells, whereas promoter M is functional only in melanoma cells. Promoter H showed the significant activity in RPE and cervical cancer cells but not in melanoma cells. In contrast, the 1.7 kb 5'-flanking region of exon 1B showed no noticeable promoter activity in these cell lines. Therefore, alternative promoters provide the MITF gene with the diversity in transcriptional regulation and the capability of generating structurally different protein isoforms.

Molecular cloning of cDNA encoding a novel microphthalmia-associated transcription factor isoform with a distinct amino-terminus

Microphthalmia-associated transcription factor (MITF) is a basic helix-loop-helix-leucine zipper protein, and plays an important role in the development of various cell types, such as neural-crest-derived melanocytes and optic-cup-derived retinal pigment epithelium. Three isoforms of MITF with distinct amino-termini have been described. These include melanocyte lineage-specific MITF-M, heart-type MITF-H, and the recently identified MITF-A. Here we identify a fourth isoform, MITF-C, with a unique amino-terminus of 34 amino acid residues, which shares about 43% sequence identity with putative transactivation segments of two previously identified leukemogenic factors, ENL and AF-9. Reverse transcription-polymerase chain reaction analysis revealed that MITF-C mRNA is expressed in many cell types, including retinal pigment epithelium, but is undetectable in melanocyte-lineage cells. In contrast, MITF-A and MITF-H mRNAs are coexpressed in all cell types examined. Transient cotransfection assays suggested that MITF-C, like other MITF isoforms, functions as a transcriptional activator of certain target genes, but its transactivation specificity for the target promoters is different from those of other MITF isoforms. Therefore, isoform multiplicity provides MITF with differential expression patterns as well as functional diversity.

Implications of isoform multiplicity of microphthalmia-associated transcription factor in the pathogenesis of auditory-pigmentary syndromes

Microphthalmia-associated transcription factor (MITF) is the human homolog of a basic helix-loop-helix-leucine zipper protein (Mitf), encoded by the mouse microphthalmia locus. Mutations in the MITF gene have been identified in some patients with Waardenburg syndrome type 2 (WS2), which is a dominantly inherited disorder, characterized by varying combinations of sensorineural hearing loss and pigmentary disturbances. Furthermore, mice with mutations at the Mitf locus are associated with various phenotypes, such as white coat color, small eyes, a deficiency in mast cells, and osteopetrosis. Thus, MITF/Mitf may play an important role in differentiation of melanocytes and some other cell types. Recently we have identified two MITF isoforms with extended amino-termini, MITF-A and MITF-H. Both isoforms possess unique amino-termini that are different from the amino-terminus of the originally identified melanocyte-specific MITF (MITF-M). MITF-M mRNA is exclusively expressed in melanocytes and pigmented melanoma cells, whereas MITF-A and MITF-H mRNA are widely expressed in many cell types, including retinal pigment epithelium. Transient transfection assays suggested that these isoforms possess differential transactivation capacity. It is therefore conceivable that the previously identified mutations may alter the functions of not only MITF-M but also MITF-A and MITF-H. Possible implications of the MITF isoform multiplicity in the pathogenesis of auditory-pigmentary disorders are discussed.

A big gene linked to small eyes encodes multiple Mitf isoforms: many promoters make light work

Among more than 80 different loci related to mouse coat color, microphthalmia-associated transcription factor (Mitf) encoded at the mouse microphthalmia locus is one of the most exciting molecules that regulates the development and survival of many cell types, including melanocyte, retinal pigment epithelium (RPE), and mast cells. Mitf and its human homolog MITF consist of at least three isoforms, referred to as Mitf-A/MITF-A, the heart-type Mitf-H/MITF-H, and the melanocyte lineage-specific Mitf-M/MITF-M, respectively. These isoforms differ in the amino-terminal domains but share a transactivation domain and a basic helix-loop-helix and leucine-zipper structure that is required for DNA binding and dimerization. MITF-M is exclusively expressed in melanocytes and melanoma cells, but not in other cell types, including RPE cells. In contrast, MITF-A mRNA is widely expressed in many cell types. These three isoform mRNAs are possibly generated by differential usage of the gene promoters and by alternative splicing. We predict that the entire MITF gene spans about 200 kb of DNA. Like MITF-M, MITF-A is able to activate the two melanogenesis gene promoters, tyrosinase and tyrosinase-related protein 1. These results suggest that melanogenesis may be regulated by different MITF isoforms in melanocyte and RPE. Possible implications of the multiplicity in Mitf/MITF isoforms are discussed.

Role of neurofibromin in modulation of expression of the tyrosinase-related protein 2 gene

Tyrosinase-related protein 2 (TRP-2)/DOPAchrome tautomerase is an enzyme involved in melanin biosynthesis and plays an important role in cytoprotection by preventing the production of a toxic melanin precursor, 5,6-dihydroxyindole. Neurofibromin is the protein product of a gene linked to neurofibromatosis type 1 (NF1), which is characterized by multiple neurofibromas and abnormalities in skin pigmentation. To explore the pathogenesis of NF1, we studied the role of neurofibromin in the regulation of TRP-2 gene expression. By means of transient cotransfection assays, we show that the expression of a reporter gene under the control of the TRP-2 gene promoter was increased by a neurofibromin-dependent signal through the 71-bp region (positions -415 to -345). A Lys-to-Glu substitution at position 1425 in neurofibromin abrogated this activating function. A dominant negative Ki-ras inhibitor mimics neurofibromin's function, and additively increases TRP-2 promoter activity when coexpressed with neurofibromin. Therefore, we suggest that neurofibromin is involved in the regulation of TRP-2 gene expression. Moreover, we found a single case of a glioblastoma multiforme that expresses TRP-2 mRNA but not tyrosinase mRNA, suggesting that TRP-2 may function in human neural tissues under certain conditions.

Identification of a novel isoform of microphthalmia-associated transcription factor that is enriched in retinal pigment epithelium

Mutations at the mouse locus encoding microphthalmia-associated transcription factor (Mitf) affect the development of many cell types, including retinal pigment epithelium (RPE), melanocytes, mast cells, and osteoclasts. Here we have identified a novel Mitf isoform, Mitf-a, and its human homologue MITF-A by cDNA cloning. MITF-A consists of 520 amino acid residues and differs in the amino-terminus from authentic melanocyte-type MITF (MITF-M). MITF-A mRNA is widely expressed and represents a predominant MITF isoform in cultured RPE cells, whereas MITF-M mRNA is exclusively expressed in melanocytes and melanoma cells. In situ hybridization analysis suggested that Mitf-a mRNA is enriched in the prospective RPE of mouse embryo. Moreover, transient cotransfection assays suggested that MITF-A activated transcription of the tyrosinase and tyrosinase-related protein 1 genes. MITF-A/Mitf-a therefore may play an important role in melanogenesis in RPE.