Hepatic proliferation in Gunn rats transplanted with hepatocytes: effect of retrorsine and tri-iodothyronine

Hepatocyte transplantation would offer an attractive alternative to liver transplantation in the treatment of inborn errors of liver metabolism. However, a major problem in most transplantation studies to date has been the limited growth of transplanted cells in the recipient organ. We performed a strategy for selective proliferation of transplanted cells by interfering with the proliferative capacity of resident hepatocytes, using the pyrrolizidine alkaloid retrorsine and then transplanting liver cells in conjunction with repeated administration of triiodothyronine, an inducer of hepatocyte proliferation in rats. In the present study, foetal and adult syngeneic hepatocyte transplantation into spleen was performed in retrorsine-treated hyperbilirubinemic Gunn rats. In parallel, repeated injections of triiodothyronine were given to recipients. Rats were sacrificed at 1, 7, 30 and 90 days after transplantation and blood and bile samples were taken to assess the functionality of transplanted cells. The proliferative activity of transplanted hepatocytes was evaluated using proliferating cell nuclear antigen labelling index. In summary, both adult and foetal hepatocyte transplantation were effective in correcting a metabolic abnormality in Gunn rats for as long as 3 months. The RS/T3 model, as a measure to increase graft function, could represent an important advance to future clinical application of hepatocyte transplantation.

First results from the CERN axion solar telescope

Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)<1.16x10(-10) GeV-1 at 95% C.L. for m(a) less, similar 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses.

Retinoic acid increases tissue and plasma contents of nerve growth factor and prevents neuropathy in diabetic mice

BACKGROUND

Decreased production of nerve growth factor (NGF) may contribute to diabetic neuropathy; however, exogenous administration of NGF induces only a modest benefit. Retinoic acid (RA) promotes the endogenous expression of nerve growth factor and its receptor. We studied the effects of RA on diabetic neuropathy in mice with streptozotocin-induced diabetes.

MATERIAL AND METHODS

One hundred and twenty National Institutes of Health (NIH) albino mice randomly separated into three groups (A, n = 30; B, n = 30; C, n = 60). Diabetes mellitus was induced with streptozotocin in groups A and B. Animals from group A received a subcutaneous injection of 25 microl of mineral oil daily for 90 days, while those from group B received a subcutaneous injection of 20 mg kg(-1) of all trans RA. Animals from group C were taken as controls. At the end of the experiment, blood glucose and NGF levels (both in serum and sciatic nerve) were measured. Two behavioural tests were conducted in a blind fashion to detect abnormalities of thermal and nociceptive thresholds.

RESULTS

Contents of NGF in healthy untreated mice were 1490 +/- 190 pg mg(-1) in nerve and 113 +/- 67 pg mg(-1) in serum; in diabetic untreated mice the values were 697 +/- 219 pg mL(-1) in nerve and 55 +/- 41 pg mL(-1) in serum; and in diabetic mice treated with RA the values were 2432 +/- 80 pg mL(-1) in nerve and 235 +/- 133 pg mg(-1) in serum (P < 0.002). Ultrastructural evidence of nerve regeneration and sensitivity tests improved in diabetic mice treated with RA as compared with nontreated diabetic mice.

CONCLUSION

Our findings indicate that administration of RA increases serum and nerve contents of NGF in diabetic mice and suggest a potential therapeutic role for retinoic acid in diabetic patients.

Methodological optimization of polyethylenimine (PEI)-based gene delivery to the lungs of mice via aerosol application

BACKGROUND

Polyethylenimine (PEI) has been successfully used for gene delivery to the lungs of mice via aerosol application using a whole body nebulization device. In this report we optimized the design of such an aerosol device.

METHODS

Aerosol devices were constructed as either serial inhalation apparatus or as a whole body nebulization chamber connected to an aerosol spacer placed in a horizontal or vertical position. PEI-based gene vectors were nebulized using a standard jet nebulizer and luciferase gene expression of various tissues was examined.

RESULTS

Using a whole body aerosol device resulted in luciferase gene expression in the lungs of mice at the same level as compared with a serial inhalation apparatus. Whereas gene expression was enhanced in the presence of 5% CO(2)-in-air, anesthesia of mice strongly decreased gene expression even when mice were intubated with an intravascular cannula. Reduction of the median mass aerodynamic diameter (MMAD) of the aerosol from 3.4 to 0.27 microm by interposition of an aerosol spacer increased gene expression significantly 3-fold. Drying of the aerosol by silica gel additionally increased gene delivery significantly 3-fold. Reporter gene expression mediated by branched PEI 25 kDa was 9- and 15-fold higher as compared with linear PEIs of 22 and 25 kDa, respectively, and was dependent on the DNA concentration. Gene expression was detectable as soon as 6 h after gene vector application and reached a maximum after 72 h but was still detectable after 14 days. The presence of Zn(2+) did not increase gene expression.

CONCLUSION

We propose aerosol drying as a novel and simple method of optimizing PEI-based gene delivery to the lungs.

Ineffective oesophageal motility does not affect the clinical outcome of open Nissen fundoplication

BACKGROUND

Nissen fundoplication is considered the 'gold standard' in antireflux surgery but some surgeons employ a different surgical strategy when gastro-oesophageal reflux disease (GORD) is associated with motor disorders of the oesophageal body.

METHODS

Ninety-three patients undergoing surgery for GORD were divided into two groups: 52 patients (group 1) had normal oesophageal body motility and 41 (group 2) had ineffective oesophageal motility (IOM). All patients had a short Nissen fundoplication via a laparotomy. The median follow-up was 5 years in group 1 and 6.5 years in group 2.

RESULTS

The clinical outcome was satisfactory in more than 90 per cent of the patients in both groups. Only one of ten patients with IOM and dysphagia before operation still had dysphagia after surgery. One patient in each group developed postoperative dysphagia. Six of 52 patients with normal motility and eight of 41 with IOM had persistent pathological acid reflux after surgery. Significant increases in contractile wave pressure and a decrease in the percentage of non-propagated waves were found in group 2 after fundoplication.

CONCLUSION

Patients with IOM did not have an increased rate of dysphagia after total fundoplication compared with those with normal motility, but they did have a higher rate of recurrence of endoscopic and pH-proven reflux.

Value of helical computed tomography in the management of upper esophageal foreign bodies

PURPOSE

To analyze the utility of helical computed tomography (CT) in the diagnosis of suspected upper esophageal foreign bodies.

MATERIAL AND METHODS

A prospective study was performed on 36 patients (26 F, 10 M, mean age 70 years) with a history of foreign body impaction. All had negative findings at indirect laryngoscopy. Radiologic assessment included unenhanced helical CT and a barium contrast study. Patients with positive findings were taken to esophagoscopy. All patients had a posterior clinical surveillance.

RESULTS

Twenty patients had both normal CT and barium study and satisfactory clinical outcome. In 12 patients a foreign body was noted in the cervical esophagus by CT, barium study, and endoscopy. In one patient a fish bone was detected by CT (and not by barium) confirmed with esophagoscopy. Another patient had a fish bone esophageal perforation which was observed only by CT and confirmed at surgery. Two patients with normal barium and endoscopy presented a false-positive CT result.

CONCLUSION

Barium swallow is currently the first radiologic study, but may involve a risk of aspiration and can impede a subsequent esophagoscopy. Esophagoscopy is an invasive technique with a certain risk of serious complications that can be avoided with a satisfactory radiologic assessment. CT is easy, fast, has 100% sensitivity and is therefore the first choice technique for diagnosing suspected upper esophageal foreign bodies not expected to be visible on plain radiographs.

Modulation of survival in osteoblasts from postmenopausal women

Osteoblast survival is one of the determinants of postmenopausal osteoporosis development. Recent data from animal experiments suggest that cytokines, in particular Fas ligand (FasL), contribute to postmenopausal osteoporosis. We now address the effect of Fas activation in postmenopausal osteoblast survival and the potential modulatory effect of estrogen and raloxifene analog (LY117018). The expression of Fas mRNA, Fas protein, and the sensitivity to Fas-induced apoptosis were studied in primary cultures of human osteoblasts from postmenopausal women and in osteoblastic MG-63 cells. Human postmenopausal osteoblasts constitutively expressed Fas receptors in the cell surface. TNFalpha increased the expression of Fas mRNA and cell surface Fas expression. Neither estradiol nor raloxifene analog prevented this increase in Fas expression. In addition, activation of Fas receptor resulted in apoptosis of postmenopausal osteoblasts. While TNFalpha did not induce human osteoblast apoptosis, it did increase the lethal effect of Fas activation. Therapeutic concentrations of estradiol or raloxifene analog did not modulate lethal cytokine-induced apoptosis. Both postmenopausal osteoblasts and MG-63 cells express FasL. FasL expression was not modulated by TNFalpha. In conclusion, estrogen and raloxifene analog do not appear to affect the sensitivity of postmenopausal osteoblasts to Fas-mediated apoptosis.

[Nutritional support in haemodialysis]

Malnutrition is a common severe problem in dialysis. The prevalence of malnutrition has been estimated as between 30% and 70%. Although malnutrition is not normally listed among the most frequent causes of mortality in these patients, it contributes to cardiovascular mortality through the MIA syndrome (Malnutrition, inflammation and arteriosclerosis) and the severity of infections. The cause of malnutrition in dialysis is frequently due to a multiplicity of factors. The use of the term malnutrition has been criticized when the cause is not scant dietary intake, for practical reasons: if the cause is not a lack of food intake, the treatment will not be an increase in the provision of nutrients. The therapeutic approach to malnutrition in dialysis has recently been reviewed. In this sense, the multifactorial origin requires the problem to be approached from different angles. The case reported is an undernourished dialysis patient in which a chronic gradual deterioration in nutritional status is treated through a multiple therapy approach.

Primary eosinophilic esophagitis

Eosinophilic esophagitis is an uncommon pathology that generally affects children with a history of allergies and intrinsic asthma. We present a clinical case of eosinophilic esophagitis in a 16-year-old boy with upper dysphagia for solids since childhood. The analytical study showed only a repeat serum eosinophilia. Barium transit disclosed a reduction in caliber of the whole esophagus. Functional esophageal tests with pH monitoring and manometry were normal. Endoscopy showed a small-diameter esophagus and fibrosis with a very friable mucosa. The histological study of the esophageal biopsies revealed a full thickness major eosinophil infiltration of the esophagus. These findings suggest a differential diagnosis with a great variety of pathologies that can cause similar lesions in the esophagus, especially between primary eosinophilic esophagitis and eosinophilic esophagitis secondary to gastro-esophageal reflux disease (GERD). We implemented medical treatment with oral corticoids and total suppression of allergens from the diet, and the patient was asymptomatic.

Diagnosis and treatment of oculopharyngeal dystrophy: a report of three cases from the same family

Oculopharyngeal muscular dystrophy is a hereditary pathology transmitted in an autosomal dominant manner. The clinical symptoms are palpebral ptosis, oropharyngeal dysphagia and proximal limb weakness. Upper gastro-esophageal endoscopy is recommended to study the dysphagia, a video-radiology study with barium and an esophageal manometry to study the pharyngeo-esophageal motor disorder. Muscle biopsy reveals the presence of atrophic fibers substituted by an increase in fat and connective tissue. In 1998 Brais described the genetic alteration responsible for this pathology, a limited expansion of the triplet of GCG nucleotides in PABP2 gene on chromosome 14q11. Normal individuals have the homozygotic form (GCG)6 of this triplet, whereas patients with the described syndrome have the heterozygotic form (GCG)6-(GCG)9 or (GCG)6-(GCG)10. We present three siblings from the same family with diagnoses and genetic confirmations of oculopharyngeal dystrophy. Two of the patients underwent cricopharyngeal myotomy to relieve the dysphagia.

[Experience with sevelamer in peritoneal dialysis]

BACKGROUND

Sevelamer is a non-absorbable phosphorus chelator that is not a source of aluminium, calcium or base. The clinical experience with sevelamer in peritoneal dialysis and in daily clinical practice is scarce. The aim of this study is to evaluate the results of therapy of hyperphosphoremia with sevelamer on serum phosphorus and phosphorus chelators requirements, in a peritoneal dialysis clinical practice.

METHODS

Sevalamer 400 mg was prescribed to peritoneal dialysis patients with hyperphosphoremia who were treated with aluminium hydroxide or with calcium salts in the absence of hypocalcemia. Fourteen patients completed 12 months of therapy.

RESULTS

The initial sevelamer dose was 2,280 +/- 760 mg/day, and was increased to 2,760 +/- 1,160 mg/day at 12 months. At 12 months no patient was on aluminium salts and calcium salts had been significantly reduced. Phosphoremia (5.9 +/- 0.6 to 5.0 +/- 1.4 mg/dL, p = 0.049), calcium-phosphorus product (59.8 +/- 5.8 to 48.6 +/- 12.5 mg2/dL2, p = 0.01) and serum cholesterol (191 +/- 29 to 167 +/- 33 mg/dL, p = 0.02) decreased at 12 months. No significant changes were observed in serum triglycerides, total CO2 or PTH. Serum alkaline phosphatase increased at 6 months, but values returned to normal at 12 months. No changes were observed in serum gamma-glutamyl-transpeptidase. Five patients were started on 1.25 (OH)2 vitamin D therapy.

CONCLUSION

In peritoneal dialysis patients, sevelamer allows a satisfactory control of serum phosphorus levels and calcium-phosphorus product, while decreasing the amount of aluminium and calcium salts prescribed.

Characterization of enteroaggregative Escherichia coli strains isolated from children with acute diarrhea, in Mendoza, Argentina

Enteroaggregative Escherichia coli (EAEC) is an increasingly recognized cause of diarrhea in children in developing and developed countries. EAEC is recognized by a characteristic aggregative pattern of adherence to human epithelial (HEp-2) cells cultured in vitro. This is the gold standard assay. The aggregative phenotype is associated with the presence of a 65 MDa plasmid (pAA) that also encodes several other putative virulence factors, such as the aggregative adherence fimbria I (AAF/I) and the enteroaggregative heat-stable enterotoxin (EAST1). The objective of this work was to evaluate the application of PCR (polymerase chain reaction) to identify EAEC strains in cases of acute diarrhea. A total of 87 E. coli strains, isolated from patients under 2 years of age with acute diarrhea in Mendoza, Argentina, were characterized by the reference method (HEp-2 assay), and by AAF/I- and EAST1-PCR. PCR sensitivity and specificity in comparison with the cell culture assay showed 94.4% sensitivity and 78.26% specificity. EAST1- and AAF/I-PCR could be recommended as a screening test, applicable to epidemiologic studies.

Apoptotic cell death in renal injury: the rationale for intervention

Cell number abnormalities are frequent in renal diseases, and range from the hypercellularity of postinfectious glomerulonephritis to the cell depletion of chronic renal atrophy. Recent research has shown that apoptosis and its regulatory mechanisms contribute to cell number regulation in the kidney. The potential role of apoptosis ranges from induction and progression to repair of renal injury. Death ligands and receptors, such as tumor necrosis factor and Fas ligand, proapoptotic and antiapoptotic Bcl2 family members and caspases have all been shown to participate in apoptosis regulation in the course of renal cell injury. However, the precise role of these proteins is unclear, and the participation of most known apoptosis regulatory proteins has not been studied. We now review the role of apoptosis in renal injury, the potential molecular targets of therapeutic intervention, the therapeutic weapons to modulate the activity of these targets and the few examples of therapeutic intervention on apoptosis, with emphasis on the acute tubular necrosis.