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Background: Tracheal stenosis is a challenging surgical problem that can require reconstruction using autologous grafts or artificial stents. In this study, we evaluate the efficacy of Surgisis, a commercially available, biocompatible, acellular matrix, in the repair of a critical-size tracheal defect., Methods: A full-thickness defect (2 mm x 6 mm) was created in tracheal rings 4 through 6 in adult rats. A piece of 8-ply Surgisis (Cook; Bloomington, IN) was sutured to the edges of the defect with interrupted 8-0 polypropylene sutures. In control animals, the defect was closed primarily. The trachea was harvested at 4 weeks and prepared for histologic evaluation using conventional techniques. Cross-sectional area and perimeters were calculated using imaging software., Results: Tracheal defects without patch repair (n = 3) resulted in tracheal stenosis and immediate death. Animals that underwent Surgisis patch repair of tracheal defects (n = 10) tolerated the procedure well and had no audible stridor or evidence of respiratory distress. Eight of ten animals survived 4 weeks. The tracheal lumen was patent with no evidence of contracture or degradation of the Surgisis. Histologically, neovascularization of the Surgisis was noted with moderate inflammation. The surface of the Surgisis patch was covered ith a lining of ciliated epithelial cells., Conclusion: In the rodent model, Surgisis appears to be an efficacious method for the patch repair of partial circumferential tracheal defects. Surgisis appears to be a safe and promising means of facilitating neovascularization and tissue regeneration. The long-term use of Surgisis warrants further investigation.

Bathing creates some of the highest levels of discomfort in the lives of individuals diagnosed with dementia. The present study measured the frequency of 14 agitated behaviors during bathing in 15 elderly residents with dementia residing in a continuing care center. Each resident was observed for four sessions of two different bathing methods, the conventional tub bath and a modification of the bed bath, known as the Thermal bath. The summed frequencies of all agitated behaviors was significantly less for the Thermal bath than the tub bath. This overall effect was greater in men than women and in one particular behavior, shivering. The results suggest that for individuals with dementia the Thermal bath offers a viable alternative to the conventional tub method. Further research may clarify other parameters, such as cost effectiveness and long-term effects of the use of non-rinse cleansers for elderly individuals.

Huntington's disease (HD) is one of eight established triplet repeat neurodegenerative disorders, which are collectively caused by the genetic expansion of polyglutamine repeats. While the mechanism(s) by which polyglutamine expansion causes neurodegeneration in each of these disorders is being intensely investigated, the underlying cause of polyglutamine toxicity has not been fully elucidated. A number of studies have focused on the potential role of protein aggregation and disruption of the proteasome proteolytic pathway in polyglutamine-mediated neurodegeneration. However, at present it is not clear whether polyglutamine-mediated protein aggregation is sufficient to induce cell death, nor has it been clearly determined whether proteasome inhibition precedes, coincides, or occurs as the result of the formation of polyglutamine-associated protein aggregation. To address these important components of polyglutamine toxicity, in the present study we utilized neural SH-SY5Y cells stably transfected with polyglutamine-green fluorescent protein constructs to examine the effects of polyglutamine expansion on protein aggregation, proteasome activity, and neural cell survival. Data from the present study demonstrate that polyglutamine expansion does not dramatically impair proteasome activity or elevate protein aggregate formation under basal conditions, but does significantly impair the ability of the proteasome to respond to stress, and increases stress-induced protein aggregation following stress, all in the absence of neural cell death.

The aim of this study was to compare traditional methods of scoring the Logical Memory test of the Wechsler Memory Scale-III with a new method based on Latent Semantic Analysis (LSA). LSA represents texts as vectors in a high-dimensional semantic space and the similarity of any two texts is measured by the cosine of the angle between their respective vectors. The Logical Memory test was administered to a sample of 72 elderly individuals, 14 of whom were classified as cognitively impaired by the Mini-Mental State Examination (MMSE). The results showed that LSA was at least as valid and sensitive as traditional measures. Partial correlations between prose recall measures and measures of cognitive function indicated that LSA explained all the relationship between Logical Memory and general cognitive function. This suggests that LSA may serve as an improved measure of prose recall.

Background/purpose: Pulmonary infiltrates in recipients of stem cell transplantation often present as diagnostic dilemmas. Although lung biopsy may establish the diagnosis of parenchymal disease, it remains unclear whether such a procedure results in a significant change in the patient's treatment and outcome. This study evaluates the efficacy of lung biopsy in recipients of stem cell transplantation., Methods: The medical records of 15 stem cell transplant recipients who underwent 18 lung biopsies were reviewed. The indications for stem cell transplantation were leukemia in 10 patients, lymphoma in 2, histiocytosis in 1, neuroblastoma in 1, and Ewing's sarcoma in 1. The results of the lung biopsies were correlated to the clinical management and outcomes., Results: The overall mortality rate was 67% (10 patients). Eight of the 9 patients who required mechanical ventilatory support at the time of lung biopsy died. The pathologic diagnoses were pneumonitis in 6 biopsies, fibrosis in 6, brochiolitis obliterans organizing pneumonia in 3, hemorrhage in 2, and infarction in 1. Therapy was changed in 1 patient who improved after a course of steroids for bronchiolitis obliterans organizing pneumonia. Lung biopsy cultures were positive in 6 patients but rarely resulted in changes in antibiotic therapy., Conclusions: Results of very few lung biopsies performed in stem cell transplant recipients redirected therapy. Furthermore, the ultimate outcome of these patients were not improved by the results of lung biopsies., (Copyright 2001 by W.B. Saunders Company.)

The clinical distinction between cystic and mucinous carcinomas of the pancreas has been poorly defined. Therefore we sought to stratify the entity known as pancreatic mucinous adenocarcinoma based on pathologic and clinical criteria. Clinical data and pathology specimens were reviewed for patients (n = 40) who had been diagnosed as having mucin-producing pancreatic adenocarcinoma and had undergone either resection or intraoperative biopsy of their pancreatic tumor during a 40-year period at the UCLA Medical Center. Based on histologic criteria, three distinct classes of pancreatic adenocarcinoma were identified: mucinous noncystic (colloid) adenocarcinoma (group I), mucinous cystadenocarcinoma (group II), and ductal adenocarcinoma (group III). Based on clinical behavior, groups I and III were indistinguishable. Compared to patients from groups I and III, those from group II were younger, more likely to be female, and had a better prognosis. Among mucin-producing adenocarcinomas of the pancreas, mucinous noncystic adenocarcinoma and ductal adenocarcinoma share similar clinical features, whereas true cystic lesions represent a distinct clinical entity.

Objective: To review the surgical experience with pectus excavatum chest deformities at UCLA Medical Center during a 30-year period., Background: Pectus excavatum is a relatively common malformation that is often symptomatic; however, children's physicians often do not refer patients for surgical correction., Methods: Hospital records from 375 patients who underwent repair of pectus excavatum deformities between 1969 and 1999 were reviewed. Decrease in stamina and endurance during exercise was reported by 67%; 32% had frequent respiratory infections, 8% had chest pain, and 7% had asthma. The mean pectus severity score (width of chest divided by distance between posterior surface of sternum and anterior surface of spine) was 4.65 (normal chest = 2.56). All patients had marked cardiac deviation into the left chest. Repair was performed with subperiosteal resection of the abnormal cartilages, transverse wedge osteotomy of the anterior sternum, and internal support with a steel strut for 6 months. Repair was performed on 177 children before age 11 years; 38 adults with severe symptoms underwent repair., Results: The mean hospital stay was 3.1 days. With a mean follow-up of 12.6 years, all patients with preoperative respiratory symptoms, exercise limitation, and chest pain experienced improvement. Vital capacity increased 11% (mean) within 9 months in 35 patients evaluated. There were no deaths. Complications included hypertrophic scar formation (35), atelectasis (12), pleural effusion (13), recurrent sternal depression (5), and pericarditis (3). More than 97% had a very good or excellent result., Conclusion: Pectus excavatum deformities can be repaired with a low rate of complications, a short hospital stay, and excellent long-term physiologic and cosmetic results.

Background: Restorative proctocolectomy is used widely for treatment of ulcerative colitis and familial polyposis coli. Limited information is available regarding the morphologic and functional adaptation of the mucosa in a functioning ileoanal pouch., Study Design: Ileal pouch specimens from patients who underwent pouch reconstruction (mean 7.5 years postcolectomy, n = 12) were compared with normal ileum (n = 15) and normal colon (n = 5). Amino-oligopeptidase (AOP) and maltase activity were measured as parameters of normal ileal function. Histologic samples were examined for the presence of neutrophils and plasma cells, the villus to crypt height ratio, and the degree of crypt hyperplasia, villus blunting, and goblet cell mass. Data were analyzed by analysis of variance., Results: The AOP activity in the normal ileum was 73 +/- 32 units of enzymatic activity per gram of mucosal protein; the AOP activities of the pouch and colon were 21 +/- 22 and 16 +/- 10, respectively. The maltase activity of the normal ileum measured 254 +/- 116 units of enzymatic activity per gram of mucosal protein, and the maltase activities of the pouch and colon were 57 +/- 71 units and 29 +/- 25 units, respectively. The ileal pouch mucosa demonstrated little acute inflammation and varying degrees of chronic inflammation. Morphologically, the ileal pouch mucosa demonstrated a range of adaptations, including villus blunting and crypt hyperplasia. Several specimens contained immature epithelial cells., Conclusions: The AOP and maltase activities in mucosa from ileoanal pouches and colon were significantly lower than those in normal ileal mucosa. Ileoanal pouch mucosa from humans undergoes adaptive changes to resemble colonic mucosa both morphologically and functionally.

A recent controversy in the field of depth perception has highlighted an important aspect of model testing concerning a model's complexity, defined as the prior propensity of the model to fit arbitrary data sets. The present article introduces an index of complexity, called the mean minimum distance, defined as the average squared distance between an arbitrary data point and the prediction range of the model. It may also be expressed as a dimensionless quantity called the scaled mean minimum distance. For linear models, theoretical values for the scaled mean minimum distance and the variance of the scaled minimum distance can be readily obtained and compared against empirical estimates obtained from fits to random data. The approach is applied to resolving the question of the relative complexity of the Linear Integration model and the Fuzzy Logic of Perception model, both of which have been the subject of controversy in the field of depth perception. It is concluded that the two models are equally complex.

Background: Esophageal replacement is associated with significant morbidity that may lead to operative interventions. This study reviews the management and outcome of children who underwent reoperation after esophageal replacement., Methods: Eighteen patients who underwent esophageal replacement from 1985 to 1997 were reviewed retrospectively. Ten patients underwent reoperation. Patient management, perioperative morbidity, and the dietary intake at follow-up were recorded for each patient., Results: Of the reoperated patients, 7 had esophageal atresia, 2 had caustic ingestion, and 1 had achalasia. Nine patients received a colon interposition, and 1 received a reverse gastric tube as the initial esophageal replacement. Seven patients required revision of the anastomoses. Three patients required complex esophageal reconstruction: 1 underwent gastric transposition, 1 underwent free jejunal graft, and 1 underwent gastric transposition combined with free jejunal graft. Seven patients were eating well at follow-up. Two patients still required partial gastrostomy tube feeding. One patient died 6 months postoperatively from aspiration pneumonia., Conclusions: Esophageal replacement continues to be a challenging operation associated with significant complications. Most reoperative procedures were directed toward strictures and persistent fistulae. Complete graft failure can be managed by gastric transposition or free jejunal graft. Despite the perioperative morbidity, most patients have good functional outcome.

The survival of infants with tracheoesophageal fistula was stratified by David J. Waterston et al. in 1962. This classification has been used as a guide to direct the timing of operative intervention in these infants. This study examines the current applicability of this classification system. The hospital records of 64 infants with esophageal atresia and/or tracheoesophageal fistula were reviewed. The survival rate was analyzed as a function of the infants' risk stratification, birth weight, and additional anomalies. Twenty-three infants were in Waterston Group A, 20 infants in Group B, and 21 infants in Group C. The survival of all infants was 81 per cent. Six infants died after recognition of severe anomalies and withdrawal of care, four infants died of cardiopulmonary arrest, and two infants died of sepsis. The survival of infants in both Groups A and B was 100 per cent, in contrast to 43 per cent survival in Group C. Only infants who weighed <1800 g or had severe additional anomalies were at risk of dying. Therefore, the classification of infants with esophageal atresia and/or tracheoesophageal fistula may be simplified by combining Waterston's Groups A and B into a single risk stratum.

Background/purpose: It has been proposed that preterm and prelabor cesarean section may improve the outcome of infants with gastroschisis. The purpose of this study is to examine the impact of gestation and delivery method on infants with gastroschisis., Methods: The medical records of 60 infants with gastroschisis treated at a tertiary care center from 1985 through 1995 were reviewed retrospectively. The gestational age, the mode of delivery, the type of operative repair, and the length of hospital stay were recorded for each patient., Results: Infants born vaginally were more likely to require silo stage repair than those delivered by cesarean section (21 of 29 v. 11 of 31, P<.01). Infants born vaginally also had longer hospital stay than those delivered by cesarean section (53 v. 39 days, P = .19). Infants born before 33 weeks' of gestation stayed longer in the hospital than those born after 33 weeks. After 33 weeks' gestation, infants had similar hospital stay regardless of the gestational age., Conclusions: Cesarean section delivery was beneficial for infants with gastroschisis. Preterm delivery did not shorten the length of hospital stay. The role of elective cesarean section delivery at term should be considered for infants with gastroschisis diagnosed antenatally.

Background/purpose: The development of dilated small intestine in patients with short bowel syndrome results in increased mucosal surface area. This study examines whether the incremental increase in surface area leads to a proportional increase in absorptive function of the small intestine., Methods: Partial obstruction of the small intestine was created in rats by placing an intussusception valve in the proximal jejunum. Rats that underwent sham operations served as controls. One week postoperatively, the small intestine proximal and distal to the valve was removed. The intestinal diameter proximal and distal to the obstruction was measured. The rate of glucose uptake was measured by the everted sleeve technique. The results were analyzed by analysis of variance (ANOVA)., Results: The intestine proximal to the valve was significantly dilated and thickened when compared with the intestine distal to the valve. The wet mass per centimeter of the dilated segment was 2.5 times that of the control group (P<.001). The glucose uptake capacity of the dilated segment was slightly higher than that of the control group (540 v 420 nmol/min/cm, P<.05). However, the specific glucose uptake rate was reduced significantly in the intestine proximal to the valve (247 v 335 nmol/min/cm2, P<.01)., Conclusions: Although the partial obstruction of small intestine resulted in a substantial increase in the intestinal surface area, the absorptive capacity of the dilated intestine per unit surface area was decreased significantly. This translated ultimately into a slight increase in the overall functional absorptive capacity of glucose in the small intestine. These results suggest that dilated small intestine may not enhance mucosal absorption.

Purpose: Intestinal stem cell transplantation is a potential method of delivering genes to the small intestine. The authors have previously demonstrated the survival of transfected intestinal stem cells implanted into the rat small intestine. This study examines the growth of genetically altered intestinal stem cells that were grown on a polycarbonate membrane and implanted into the rat small intestine., Methods: The IEC6 rat intestinal cell line serves as a model for intestinal stem cells. A subclone of the IEC6 cells was developed that stably expresses the lac Z gene introduced by a retroviral vector. The transfected cells were seeded at 500,000 cells/cm2 on a polycarbonate membrane. In 15 male Sprague-Dawley rats, a 0.75-cm enterotomy was created on the antimesenteric side of the small intestine 5 cm distal to the ligament of Treitz. A 0.5-cm2 segment of the membrane was sutured over the enterotomy with the cells facing away from the intestinal lumen. A segment of the omentum was wrapped around the patched enterotomy and sutured to the serosa. Three and 7 days after implantation, the implanted cells were retrieved, then fixed and stained with an X-gal solution. The number of cells was determined from the intensity of the X-gal staining. In five of the rats, frozen sections of the enterotomy sites were examined after staining with X-gal., Results: All 15 rats survived the implantation procedure. Initially, 0.32 +/- 0.11 million cells were implanted. At both 3 and 7 days, the enterotomy site still contained viable transfected cells. The number of viable cells increased substantially to 1.52 +/- 0.46 and 3.52 +/- 1.87 million cells at 3 and seven days, respectively (P < .05)., Conclusions: The polycarbonate membrane served as a good vehicle to efficiently deliver genetically altered intestinal stem cells to the small intestine. The transplanted cells continued to grow and stably expressed the gene product. This ex vivo approach to gene therapy has considerable therapeutic potential.

Background/purpose: The exposure to research during residency is currently an integral part of most academic surgical training programs. In this study, graduates of two surgical programs were surveyed to characterize their research experience and to determine the effects on their careers., Methods: Between 1975 and 1990, 86 and 61 residents completed general surgical training programs at UCLA Medical Center and at Harbor-UCLA Medical Center, respectively. An anonymous survey was sent to each graduate regarding his research experience and current practice., Results: Of the graduates who spent 2 years in research, 47% now hold academic positions, compared with 23% for those who spent less than 2 years (P = .18). When the graduates were segregated according to their desire to enter the laboratory, 49% of graduates who requested research time hold academic positions, whereas only 13% of those who would not request research are in academic positions (P = .01)., Conclusions: Residents who strongly desire a period of research during surgical residency are also more productive in the laboratory. This information should be considered in selecting residents for research training in the current era of academic budget restriction and managed health care.

Background: The operative management of children with combined gastroesophageal reflux and delayed gastric emptying is controversial. This study measures the long-term follow-up of gastric emptying in children who have undergone gastroesophageal fundoplication combined with antroplasty., Methods: Fifteen randomly selected children with gastroesophageal reflux and scintigraphically demonstrated delayed gastric emptying underwent fundoplication and antroplasty. Each patient had another gastric emptying scintigraphic study performed an average of 3.6 years postoperation., Results: All patients reported improvement of their symptoms compared with before the operation, and none required further medical therapy for gastroesophageal reflux or experienced dumping syndrome. Eleven of the 15 patients had significant long-term improvement of their gastric emptying postoperatively. The mean percent of isotope meal remaining in the stomach at 90 minutes improved from 72% preoperatively to 40% postoperatively (P = 0.0005)., Conclusions: Gastric emptying in children with gastroesophageal reflux and delayed gastric emptying is significantly improved for several years in three-fourths of patients after fundoplication and antroplasty. Fundoplication and concomitant antroplasty are recommended for symptomatic children with documented gastroesophageal reflux and delayed gastric emptying.

Background: The surgical management of patients with omphalocele has evolved over the past 4 decades. Despite many improvements in care, the reported mortality has been over 10%., Methods: This study reviewed the characteristics, management, and outcome of 31 patients with omphalocele who underwent surgical care between 1980 and 1995 at a single hospital., Results: Twenty-five patients had additional congenital anomalies. All but 1 patient underwent operative repair; 13 of these patients with large defects had a silo chimney constructed initially. Fourteen patients underwent primary fascial and skin closure at the initial operation. Only 1 patient died perioperatively; another patient died without operation due to other major malformations., Conclusions: The results following surgical repair of omphalocele defects depend on the degree of visceroabdominal disproportion and on the severity of associated anomalies. The operative mortality for staged omphalocele repair with limited elevation of intraabdominal pressure is low, and the long-term quality of life of these patients is good.

After massive small bowel resection, the intestine adapts to compensate. In addition to proliferation, enterocytes also undergo selective functional adaptation. In this study we examined the effect of intraperitoneal administration of epidermal growth factor (EGF) on the expression of the brush border dissacharidase sucrase, the sodium glucose cotransporter (SGLT1), and the sodium-potassium ATPase pump (NaK ATPase) by enterocytes in the remnant intestine after massive small bowel resection. Adult Lewis rats underwent either ileal transection or 70% proximal intestinal resection. These animals were subdivided into groups that received either saline or EGF intraperitoneally for 1 week. Ilea from each group were harvested 4 weeks postoperatively. Enterocytes were separated from these segments by calcium chelation. The total protein from the isolated cells was subjected to Western blot analysis. Administration of EGF to animals that underwent transection did not significantly alter the expression of sucrase, SGLT1, or NaK ATPase. After intestinal resection, the expressions of sucrase and SGLT1 were significantly increased. The combination of EGF administration and intestinal resection resulted in a further increase in SGLT1 expression. The intraperitoneal administration of EGF selectively enhanced the expression of SGLT1 by enterocytes after massive small bowel resection. Administration of EGF to sham-operated animals did not have similar effects. These results suggest that EGF augments the adaptive response and may therefore have a therapeutic role in the management of patients with short bowel syndrome.

Continuous ambulatory peritoneal dialysis (CAPD) is a safe and effective treatment for children with end-stage renal failure. Approximately three per cent of patients develop a large hydrothorax as a result of a dialysate leak from the peritoneal cavity through an occult diaphragmatic eventration or attenuation of the pleuroperitoneal membrane. Previously, such patients often discontinued CAPD and were placed on hemodialysis even though the complications, expense, and limitation of activity with hemodialysis are undesirable in children. During the past 15 years, 6 of the 193 children (3%) undergoing CAPD at UCLA Medical Center developed a hydrothorax. Three patients were male and three were female. Four patients were treated surgically with diaphragmatic plication, one was treated by reducing the dialysate volume, and one was switched to hemodialysis in preparation for a renal transplant. Each of the four surgically-treated children was able to return to full-volume peritoneal dialysis and has not experienced recurrence of the hydrothorax. Therefore, diaphragmatic plication permits children to quickly resume full-volume CAPD and avoid hemodialysis.

Background: The intestine is a target of septic insult. The aims of this study were to characterize sepsis-induced alterations in intestinal ion transport and to determine the role endotoxin plays in mediating these changes., Methods: Rats underwent cecal manipulation alone (control), cecal ligation and puncture (CLP), or CLP plus intraperitoneal injection of 0.2 mg of a recently synthesized endotoxin inhibitor. At 24 hours, distal ileum was harvested, and transport parameters were determined., Results: Cecal ligation and puncture produced a significant increase in short-circuit current (Isc) that was attributable to the induction of chloride secretion. There were no alterations in transepithelial resistance or fluxes of mannitol and sodium. The sepsis-induced increase in Isc was prevented by administration of the endotoxin inhibitor., Conclusions: In this model of sepsis, the primary alteration in ileal ion transport is an induction of electrogenic chloride secretion. Endotoxin inhibition may represent a strategy for prophylaxis against the intestinal effects of sepsis.

Meal-stimulated colonic absorption has recently been described, but the cellular transport mechanisms mediating this response are unknown. The purpose of this study was to determine the contribution of Na+ transport pathways to colonic proabsorption. Distal colonic Thiry-Vella loops were constructed in six dogs. Absorption was measured by infusing the loops with a physiological electrolyte solution containing [14C] polyethylene glycol as the impermeant marker. In the first set of experiments, the dose dependence of amiloride-induced inhibition of basal colonic absorption was determined. In the second set of experiments the effect of amiloride, which inhibits both Na+ channels and Na+/H+ exchange in colonocytes, on meal-stimulated colonic absorption was determined. Luminal amiloride inhibited basal colonic absorption in a dose-dependent manner, with significant reductions in Na+ absorption occurring with concentrations of 10(-2)M and higher. Infusion with 10(-3)M amiloride, a concentration that did not alter basal absorption, resulted in significant reductions in postprandial water, Na+, and Cl- absorption. These results suggest that meal-stimulated colonic absorption is mediated, at last in part, by transcellular Na+ absorptive pathways.

Following massive small bowel resection, the remaining intestine undergoes compensatory adaptation to maintain absorptive capacity. The purpose of this study was to determine the relative importance of mucosal hyperplasia and functional adaptation by individual enterocytes in this process. Distal ileum was harvested from rats 2 weeks following 70% small bowel resection or transection with reanastomosis. Transport parameters were determined in Ussing chambers. Short-circuit current (Isc) responses to additions of 3-0-methylglucose were measured to assess Na+/glucose cotransporter kinetics. Microvillus absorptive surface areas were calculated with computer-assisted morphometric modeling. These surface area values were used to normalize transport parameters. Ileal absorptive surface area was 70% greater in resection tissues than in transection tissues (P < 0.05). Na+ and Cl- fluxes were generally lower in the resection group. Na+/glucose cotransporter delta Isc max (an index of cotransporter quantity) for resection and transection tissues were 0.3 +/- 0.1 and 1.8 +/- 0.3, respectively (P < 0.05). Km (an index of cotransporter affinity for substrate) did not differ significantly. Following intestinal resection, ileal surface area increases; however, transport parameters, when normalized to absorptive surface area values, diminish. During early postresection adaptation, expansion of ileal absorptive surface area due to hyperplasia seems to play a greater role than upregulation of enterocyte Na+, Cl- , and glucose absorption.

The cytoskeleton is important in the maintenance of cellular morphology and differentiated function in a number of cell types, including hepatocytes. In this study, adult rat hepatocytes sandwiched between two layers of collagen gel were compared to cells cultured on a single collagen gel for differences in the organization and expression of the cytoskeletal proteins actin and tubulin. Hepatocytes cultured between two layers of hydrated rat tail tendon collagen (sandwich gel) morphologically resembled cells in intact liver for several weeks. Actin filaments (F-actin) in these hepatocytes were concentrated under the plasma membrane in regions of cell-cell contact. In contrast, hepatocytes cultured on a single collagen gel were flattened and motile and had F-actin containing stress fibers. This was accompanied by a severalfold increase in actin mRNA. Microtubules formed an interwoven network in hepatocytes cultured in a sandwich gel, but in single gel cultures they formed long parallel arrays extending out to the cell periphery. Tubulin mRNA was severalfold greater in hepatocytes cultured on a single gel. Fibronectin and laminin staining were greater in single gel cultures, and these proteins were concentrated in fibrils radiating from the cell periphery. Overlaying a second collagen gel onto hepatocytes that had been cultured on a single gel (double gel rescue) reversed cell spreading and reduced stress fibers. Double gel rescue also resulted in a decrease in actin and tubulin mRNA to levels present in sandwich gel cultures and freshly isolated hepatocytes. These results show that the configuration of the external matrix has a dynamic effect on cytoskeletal proteins in cultured rat hepatocytes.

A mathematical model which simulates the dynamic behavior of the hepatocytes cultured in a collagen sandwich is presented. Using several independently determined experimental parameters (e.g., albumin gene nuclear runoff activity, the level of albumin mRNA, and the albumin secretion rate), we have used this model to calculate the in vivo albumin gene transcriptional rate (0.27 molecules per second per hepatocyte), the half-life of albumin mRNA (3.3 days) in cultured hepatocytes, and the albumin polypeptide elongation rate (10 amino acids per second). In addition, the characteristic time constants for the transient increases in transcription (5 days) and in translation (10 days) were also obtained. These best fit parameters were used to predict the rate of albumin secretion in rescued hepatocytes., ((c) 1993 John Wiley & Sons, Inc.)

This article reports the neuropsychological sequelae of Wernicke's Encephalopathy in a 20-year-old woman. After amelioration of acute symptoms, the patient showed a range of cognitive impairments the most marked of which was a severe impairment on free recall tasks involving both verbal and nonverbal material. In contrast, recognition memory appeared remarkably well preserved. Some evidence of frontal lobe and general intellectual impairment was also noted. The case is discussed in terms of the pathophysiology of Wernicke-Korsakoff Syndrome, criteria for its diagnosis, and the multicomponent nature of memory deficits.

Hepatocytes have been used extensively both in vitro and in vivo for a wide variety of studies. Although isolated hepatocytes appear similar to their in vivo counterparts, they are different in some respects. One aspect in which they differ is their ability to translate proteins. The isolation process appears to inflict sufficient damage to reduce the average polyribosome size within the isolated hepatocytes and this size reduction correlates with a lower rate of protein production. Two methods of liver perfusion that better maintain the normal distribution of polyribosomes are described in this report. It is clear from these studies that new isolation methods that result in high yields of viable hepatocytes that function maximally are needed.

Blastocystis hominis is a unicellular organism the pathogenic potential of which in humans remains unclear. It may be identified during a workup for gastrointestinal symptoms, usually in stool examined for ova and parasites. We describe a case in which B hominis was identified by cytologic examination in a patient with Crohn's disease who underwent colonoscopy and brushing of a transverse colon stricture. The morphologic features of this organism are described and contrasted with those of the uninucleate cyst form of Entamoeba histolytica.

The influence of extracellular matrix configuration on the tissue-specific function of cultured hepatocytes was investigated. Adult rat hepatocytes sandwiched between two layers of collagen gel were compared to cells cultured on a single layer of collagen gel for differences in the total RNA content, the level of albumin-specific mRNA, the rate of albumin gene transcription, and the rate of albumin mRNA translation. Adult hepatocytes in the sandwich system maintained the level of albumin mRNA similar to that found in the normal liver for at least six weeks, whereas the level of albumin mRNA declined rapidly in the single gel system. After one week of culture, hepatocytes in the single gel system could be induced to recover the high level of albumin mRNA and albumin production when a second layer of collagen gel was overlaid at that time. Furthermore, sandwiched hepatocytes maintained significantly higher transcriptional activity compared to cells in the single gel system. In addition to transcriptional control, the ultimate rate of albumin production was shown to depend on the rate of translation, which increased with culture time and reached a plateau in one to two weeks. This increase in translational activity over time in culture was observed in both the sandwich and the single gel systems and, thus, appeared to be independent of the configuration of extracellular matrix.

Despite more than 30 yr of research and development, an artificial liver has still not yet become clinical reality. Although previous attempts using a multiplicity of techniques including hemodialysis, hemoperfusion, plasma exchange, extracorporeal perfusion, and crosshemodialysis have shown minor improvement in patients with acute hepatic failure, limited clinical trials have failed to demonstrate any survival benefit. Encouraged by the progress on techniques that maintain long-term cultures of hepatocytes, more recent efforts have been directed at the use of hepatocytes as the basis of liver support. This review takes a critical look at past and present concepts in the development of artificial liver supports and both qualitatively and quantitatively evaluates the advantages and disadvantages of the available methodology.

In an effort to reconstruct the cellular polarity normally found in the liver, adult rat hepatocytes were sandwiched between two layers of hydrated rat tail tendon collagen matrix. Functionally, sandwiched hepatocytes maintained the secretion of albumin, transferrin, fibrinogen, bile acids, and urea for at least 6 weeks, whereas cells cultured on a single layer of collagen gel ceased such secretion in 1-2 weeks. After 1 week of culture on a single layer of collagen gel, hepatocytes could still recover these lost functions when a second layer of collagen gel was applied. The exact nature of the substrate for constructing the sandwich system appeared to be unimportant as long as it allowed cellular attachment. Hepatocytes cultured in the sandwich system appeared to maintain a distribution of actin filaments similar to the in vivo state, whereas cells cultured on a single layer of collagen gel showed abnormal formation of stress fibers. These studies suggest that simple manipulations of the configuration of extracellular elements can dramatically alter the behavior of cultured hepatocytes.

Current methods of cryopreservation of hepatocytes in single cell suspensions result in low overall yields of hepatocytes, demonstrating long-term preservation of hepatocellular functions. A novel culture method has recently been developed to culture liver cells in a sandwich configuration of collagen layers in order to stabilize the phenotypic expression of these cells in vitro (J. C. Y. Dunn, M. L. Yarmush, H. G. Koebe, and R. G. Tompkins, FASEB J. 3, 174, 1989). Using this culture system, rat hepatocytes were frozen with 15% (v/v) Me2SO to -70 degrees C, and stored at approximately -100 degrees C. Following rapid thawing, long-term function was assessed by measuring albumin secretion in culture for 7-14 days postfreezing. Comparison was made with cryopreservation of liver cells in single cell suspensions. Cryopreservation of liver cells in suspension resulted in only a 2% yield of cells which could be successfully cultured; albumin secretion rates in these cultured cells over 48 hr were 26-30% of secretion rates for nonfrozen hepatocytes. Freezing cultured liver cells in the sandwich configuration after 3, 7, and 11 days in culture maintained 0, 26, and 19% of the secretion rates of nonfrozen hepatocytes, respectively. Morphology of the cryopreserved cells appeared grossly similar to cells without freezing; however, this morphological result was patchy and represented approximately 30% of the cells in culture. These results represent the first demonstration of any quantitative long-term preservation of hepatocellular function by cryopreservation, suggesting that cultured hepatocytes can survive freezing and maintain function.

A multidisciplinary study group was established to assess impotent patients. One hundred and forty-eight patients were fully assessed and 25 potent volunteers underwent measurement of nocturnal penile tumescence (NPT). This report describes the selection process and results of surgical implantation of the American Medical Systems (AMS) inflatable and the Jonas silver-silicone prostheses.

Androgen-binding protein (ABP) is present in the guinea-pig testis, epididymis and epididymal fluid. Guinea-pig ABP sediments as an approx. 4.6S species on sucrose gradients containing 0.01 M KCl. Electrophoresis on non-denaturing polyacrylamide gels indicated that specific androgen binding was present in epididymal cytosol, but not in plasma. Time-course studies indicated that binding equilibrium is approached in about 2.5 h; the dissociation half-time of [3H]5 alpha-DHT from guinea-pig ABP is 5.64 +/- 0.62 h (n = 6) at 4 degrees C. The relative affinities of some steroids for guinea-pig ABP in relation to 5 alpha-DHT = 1 are: testosterone = 0.55 +/- 0.13 (n = 4), estradiol = 0.14 +/- 0.03 (n = 4), the anti-androgen cyproterone acetate = 0.0025 +/- 0.0002 (n = 3). Guinea-pig ABP exhibited an equilibrium dissociation constant of 6.34 +/- 0.52 nM (n = 3) at 4 degrees C and there were 3.43 +/- 0.78 (n = 3) pmoles of binding sites per mg of protein when homogenates of the whole epididymis were assayed. The concentration of ABP was lowest in the caput-corpus region of the epididymis, highest in the proximal cauda, and intermediate in the distal cauda. Essentially all of the ABP present in the distal cauda was intraluminal, as evidenced by the fact that flushing of the duct eliminated most of the [3H]5 alpha-DHT binding activity.

Adult rat hepatocytes cultured in a collagen sandwich system maintained normal morphology and a physiological rate of albumin secretion for at least 42 days. Hepatocytes cultured on a single layer of collagen gel essentially ceased albumin secretion within 1 wk but could recover function with the overlay of a second layer of collagen gel. This culture configuration more closely mimics the hepatocytes' in vivo environment and provides a simple method for their long-term maintenance.

Heat transfer rates in a basaltic magma were measured under typical magma chamber conditions and a numerical model of the experiment was used to estimate magma viscosity. The results are of value for assessing methods of thermal energy extraction from magma bodies in the upper crust as well as for modeling the evolutionary track of these systems.

Two experiments were conducted to investigate the relationship between dimensional integrality and the form of the combination rule or spatial metric used in a similarity judgment task. In Experiment 1, two groups of eight subjects judged the dissimilarity of all pairwise combinations of 12 rectangles differing in height and width (integral dimensions) or 12 circles differing in size and diameter orientation (separable dimensions). The dimensional organization and spatial metric of both sets of dimensions were determined. The results showed that differences in height and width contributed independently to judgments of the overall dissimilarity of rectangles and that these dimensions were combined using a Euclidean metric. In contrast, substantial interactions between circle size and diameter orientation were found. Combinations of these dimensions also appeared to violate the triangle inequality implying that no spatial metric was appropriate. In Experiment 2, parallelogram size and tilt were similarly analyzed. Although some degree of dimensional interaction was observed, it was found that on the average these dimensions were combined using a city-block metric. In a subsequent speeded classification task, orthogonal interference was observed, which suggested that size and tilt are integral dimensions. The implications of both experiments for the supposed association between the Euclidean metric and dimensional integrality are discussed.