Tissue Regrowth Research Articles

Regrowth of embryogenic tissues of Pinus nigra following cryopreservation

Embryogenic tissues of a conifer species Pinus nigra Arn. have been cryopreserved by a slow-freezing method. The effect of cryoprotective compounds such as maltose, sucrose or sorbitol (each 0.5 M) combined with 7.5% (v/v) DMSO has been tested. After thawing, the following parameters have been investigated: tissue regrowth 6 weeks after thawing, and post-thaw growth evaluated as fresh mass accumulation as well as genetic stability in post-thaw period. The parameters mentioned have been compared in both cryopreserved and non-cryopreserved tissues. Out of eight cell lines used in experiments, seven survived cryopreservation (87.5% regrowth), although cell line and treatment effects were observed. In most cell lines, sucrose or maltose pretreatments were superior over sorbitol. In the regrown cell lines, the post-thaw growth as fresh mass accumulation was not negatively influenced by cryopreservation. No genetic variation was observed in cryopreserved tissues using a RAPD approach.

Histopathological evaluation of recurrent goiter.

The recurrent goiter is the regrowth of thyroid tissue after thyroidectomy. An inadequate surgical removal of the thyroid gland, lack of substitution therapy and pathological stimulation of the thyroid growth can all promote the recurrence. The aim of this study was to find the connection between the histopathological findings during the first and second operation and the recurrence of goiter. The study group consisted of 29 women and 1 man. The mean time to recurrence was 15 years. The most frequent histopathological finding during the first and second operation was struma nodosa. According to our observations different histopathological findings were found in 63.4% cases after primary and secondary thyroidectomy. Some genetic investigations showed that nodules in recurrent goiters did not derive from nodules left during the first operation but from a group of cells which had high growth potential. Thus, not only the operation technique and substitution after operation are key factors of successful therapy of goiter, but also other factors which stimulate the re-growth of thyroid tissue.

Shading, Defoliation and Light Enrichment Effects on Chickpea in Northern Latitudes

AbstractChickpea (Cicer arietinum L.) has an indeterminate growth nature, and the plant canopy with an improved light environment during critical growth stages may increase biomass (BM) production and improve crop yield. This study examined (i) the effects of shading, light enrichment and defoliation applied at various growth stages on BM and seed yield of chickpea in northern latitudes; and (ii) the difference between cultivars with fern‐ vs. unfoliate‐leaf type in responding to the altered canopy light environments. Field studies were conducted at Saskatoon and Swift Current, Saskatchewan in 2004 and 2005. Different light environments were created by 50 % defoliation at vegetative growth and at first flower, 50 % shading from vegetative growth to first flower, and two light enrichment treatments initiated at the first flower and pod formation stages. The 50 % shade treatment prior to flowering significantly decreased harvest index (HI) and seed yield. Light enrichments increased seed yield only one of three location‐years (the fourth site excluded because of disease damage). Defoliation at vegetative growth or first flower had a marginal effect on seed yield, largely as a result of the regrowth of vegetative tissues compensating for the lost plant tissues. The cultivar CDC Yuma (fern‐leaf type) exhibited consistently greater maximum light interception (LI), cumulative intercepted radiation, HI and seed yield than the cultivar Sanford (unifoliate‐leaf type) across all location‐years. Selective use of chickpea cultivars with improved morphological traits such as fern‐leaf type will likely improve LI and increase crop yield for chickpea in northern latitudes. Moreover, optimized crop management practices should be adopted to ensure that chickpea be grown under conditions with minimum shading before flowering and optimum light environment within the canopy especially during reproductive growth period.

Why do palatine tonsils grow back after partial tonsillectomy in children?

Within the last decade, adenoidectomy with partial tonsillectomy has been revived in children with obstructive sleep-disordered breathing caused by adenotonsillar hyperplasia, generating debate about remaining tonsillar tissue regrowth. The study examined potential risk factors of the regrowth. Prospective, nonrandomised, case series feasibility study of children meeting the criteria for palatine tonsils regrowth after partial tonsillectomy performed in patients with obstructive sleep-related breathing disorder was carried out. Out of 793 operated children, 294 after adenoidectomy and 373 after adenotonsillotomy were followed up for 4 years in 12-month intervals. In 27 children after adenotonsillotomy, regrowth of tonsillar tissue was observed. In 22 individuals after adenoidectomy alone, hyperplasia of palatine tonsils was noted. The children had bacterial cultures of pharyngeal smears and blood samples tested for anti-streptolysin O, C-reactive protein and total IgE. Caregivers completed a questionnaire reporting on: their child's breathing after surgery; frequency, severity and treatment of upper respiratory tract infections; diet; family history of adenoidal and/or tonsillar hyperplasia; and history of allergy. As controls, 272 participants after adenoidectomy alone and 346 after adenotonsillotomy were examined. The amount of sugar in the diet and the incidence of upper respiratory tract infections after surgery differed between the groups of patients and controls. Other differences were insignificant. The tonsillar tissue remaining after partial tonsillectomy in children has a remarkable tendency to grow back, related to a diet abundant in sugar and numerous upper respiratory tract infections. Tonsillar regrowth was age related and occurred most frequently in individuals older than 7 years.

Role of plasminogen activator inhibitor-2 (PAI-2) in keratinocyte differentiation

Plasminogen activator inhibitor-2 (PAI-2) is an enzyme inhibitor which is involved in various biological processes including cell differentiation, tissue regrowth and regeneration. Although PAI-2 has been originally isolated as an extracellular inhibitor of urokinase plasminogen activator (uPA), recent studies indicate that PAI-2 has other intracellular effects in keratinocyte, such as the component of cornified envelope. The aim of this study is to investigate the expression and functional role of PAI-2 during the keratinocyte differentiation. We transduced keratinocytes with adenovirus harboring the expression cassette for PAI-2, then examined the effect on keratinocytes differentiation. When cultured epidermal keratinocytes were treated with 1.2 mM calcium, PAI-2 expression was increased time-dependently at both mRNA and protein levels. The calcium-induced PAI-2 expression was abolished by treatment with p38 MAPK inhibitor, while overexpression of MKK6 led to the increase of PAI-2 expression. When PAI-2 was overexpressed by adenoviral transduction, the expression of keratinocyte differentiation markers such as involucrin, keratin 10 and loricrin was markedly increased. Concomitantly, overexpression of PAI-2 resulted in the retardation of cell growth, with the increase of Rb and p53. These results suggest that PAI-2 has a role for promoting the differentiation of epidermal keratinocytes.

In this issue

AbstractProhibition that works: Prohibitin 1Prohibitin 1 (Phb1) was cloned in 1991 based on its ability to suppress the regrowth of liver tissue. That task was not trivial – Phb1 turned out to be a buddy of just about anyone of any importance. It is highly conserved, ubiquitous among eukaryotes, and exerts a controlling interest in apoptosis, cell cycle, differentiation, and senescence. It, in turn, is controlled by a variety of post‐translational modifications. Did I say it is a tumor suppressor, too? It is. Sánchez‐Quiles et al. set out to survey the effects of changing levels of Phb1 on a variety of cell functions in cultured human hematoma cells. Using si technology, they found more that than 500 genes were stimulated or repressed in one liver cell line. One partial explanation is the observation that Phb1 is also involved in tissue homeostasis through two interacting networks.magnified imagepp. 1609–1620Myxobacter mixes mean mixture for mealsMost of us learned what we know of microbiology in medical settings, concerned about infectivity, clinical symptoms and drug resistance. Some of us (“molecular biologists”) never got beyond Escherichia coli and Bacillus subtilis. The excuse for working with so few species of bacteria was that it took too long to move all the genetic and biochemical tools into a new species. We can no longer hide behind that excuse. Entire genomes can be sequenced in a matter of weeks (or days). In this study, Chao et al. analyze the proteomic response of Anaeromyxobacter dehalogenans to changes in nutrients including uranium(VI), halogenated phenols, Fe(III) to fumarate as electron acceptors. Applying commonly used proteomic tools (2‐DE/MALDI‐TOF), they found spots for 559 unique proteins. Pathway analysis revealed an unusually wide array of means of living off of amino acid metabolism (like lysine to butyrate fermentation).magnified imagepp. 1685–1693“Brain must be in gear before starting mouth”This group clearly had their brain in gear. Sievers et al. gave Staphylococcus aureus every chance to respond “normally” to the deletion of a critical gene but virtually nothing changed on first glance. It was expected that deletion of lysyl‐phosphatidylglycerol synthase (lys‐PGS) would cause a major change in the cell membrane proteome. Only 1.5–3.5% of cell envelope proteins shifted up or down out of more than 35% of theoretical. The levels of lipid biosynthetic enzymes were unchanged. What was affected were the stress sensing regulatory proteins and their targets. When it comes to specifying new drug targets, lys‐PGS must be approached with care – it's mouth may already be engaged.magnified imagepp. 1694–1698

Cover Picture: Proteomics 8'10

AbstractProhibition that works: Prohibitin 1Prohibitin 1 (Phb1) was cloned in 1991 based on its ability to suppress the regrowth of liver tissue. That task was not trivial – Phb1 turned out to be a buddy of just about anyone of any importance. It is highly conserved, ubiquitous among eukaryotes, and exerts a controlling interest in apoptosis, cell cycle, differentiation, and senescence. It, in turn, is controlled by a variety of post‐translational modifications. Did I say it is a tumor suppressor, too? It is. Sánchez‐Quiles et al. set out to survey the effects of changing levels of Phb1 on a variety of cell functions in cultured human hematoma cells. Using si technology, they found more that than 500 genes were stimulated or repressed in one liver cell line. One partial explanation is the observation that Phb1 is also involved in tissue homeostasis through two interacting networks.Sánchez‐Quiles, V. et al., Proteomics 2010, 10, 1609–1620.Myxobacter mixes mean mixture for mealsMost of us learned what we know of microbiology in medical settings, concerned about infectivity, clinical symptoms and drug resistance. Some of us (“molecular biologists”) never got beyond Escherichia coli and Bacillus subtilis. The excuse for working with so few species of bacteria was that it took too long to move all the genetic and biochemical tools into a new species. We can no longer hide behind that excuse. Entire genomes can be sequenced in a matter of weeks (or days). In this study, Chao et al. analyze the proteomic response of Anaeromyxobacter dehalogenans to changes in nutrients including uranium(VI), halogenated phenols, Fe(III) to fumarate as electron acceptors. Applying commonly used proteomic tools (2‐DE/MALDI‐TOF), they found spots for 559 unique proteins. Pathway analysis revealed an unusually wide array of means of living off of amino acid metabolism (like lysine to butyrate fermentation).Chao, T.‐C. et al., Proteomics 2010, 10, 1685–1693.“Brain must be in gear before starting mouth”This group clearly had their brain in gear. Sievers et al. gave Staphylococcus aureus every chance to respond “normally” to the deletion of a critical gene but virtually nothing changed on first glance. It was expected that deletion of lysyl‐phosphatidylglycerol synthase (lys‐PGS) would cause a major change in the cell membrane proteome. Only 1.5–3.5% of cell envelope proteins shifted up or down out of more than 35% of theoretical. The levels of lipid biosynthetic enzymes were unchanged. What was affected were the stress sensing regulatory proteins and their targets. When it comes to specifying new drug targets, lys‐PGS must be approached with care – it's mouth may already be engaged.Sievers, S. et al. Proteomics 2010, 10, 1694–1698.

In this issue

AbstractProhibition that works: Prohibitin 1Prohibitin 1 (Phb1) was cloned in 1991 based on its ability to suppress the regrowth of liver tissue. That task was not trivial – Phb1 turned out to be a buddy of just about anyone of any importance. It is highly conserved, ubiquitous among eukaryotes, and exerts a controlling interest in apoptosis, cell cycle, differentiation, and senescence. It, in turn, is controlled by a variety of post‐translational modifications. Did I say it is a tumor suppressor, too? It is. Sánchez‐Quiles et al. set out to survey the effects of changing levels of Phb1 on a variety of cell functions in cultured human hematoma cells. Using si technology, they found more that than 500 genes were stimulated or repressed in one liver cell line. One partial explanation is the observation that Phb1 is also involved in tissue homeostasis through two interacting networks.magnified imagepp. 1609–1620Myxobacter mixes mean mixture for mealsMost of us learned what we know of microbiology in medical settings, concerned about infectivity, clinical symptoms and drug resistance. Some of us (“molecular biologists”) never got beyond Escherichia coli and Bacillus subtilis. The excuse for working with so few species of bacteria was that it took too long to move all the genetic and biochemical tools into a new species. We can no longer hide behind that excuse. Entire genomes can be sequenced in a matter of weeks (or days). In this study, Chao et al. analyze the proteomic response of Anaeromyxobacter dehalogenans to changes in nutrients including uranium(VI), halogenated phenols, Fe(III) to fumarate as electron acceptors. Applying commonly used proteomic tools (2‐DE/MALDI‐TOF), they found spots for 559 unique proteins. Pathway analysis revealed an unusually wide array of means of living off of amino acid metabolism (like lysine to butyrate fermentation).magnified imagepp. 1685–1693“Brain must be in gear before starting mouth”This group clearly had their brain in gear. Sievers et al. gave Staphylococcus aureus every chance to respond “normally” to the deletion of a critical gene but virtually nothing changed on first glance. It was expected that deletion of lysyl‐phosphatidylglycerol synthase (lys‐PGS) would cause a major change in the cell membrane proteome. Only 1.5–3.5% of cell envelope proteins shifted up or down out of more than 35% of theoretical. The levels of lipid biosynthetic enzymes were unchanged. What was affected were the stress sensing regulatory proteins and their targets. When it comes to specifying new drug targets, lys‐PGS must be approached with care – it's mouth may already be engaged.magnified imagepp. 1694–1698

Visceral regeneration in a sea cucumber involves extensive expression of survivin and mortalin homologs in the mesothelium

BackgroundThe proper balance of cell division and cell death is of crucial importance for all kinds of developmental processes and for maintaining tissue homeostasis in mature tissues. Dysregulation of this balance often results in severe pathologies, such as cancer. There is a growing interest in understanding the factors that govern the interplay between cell death and proliferation under various conditions. Survivin and mortalin are genes that are known to be implicated in both mitosis and apoptosis and are often expressed in tumors.ResultsThe present study takes advantage of the ability of the sea cucumber Holothuria glaberrima Selenka, 1867 (Holothuroidea, Aspidochirota) to discard its viscera and completely regrow them. This visceral regeneration involves an extensive expression of survivin and mortalin transcripts in the gut mesothelium (the outer tissue layer of the digestive tube), which coincides in time with drastic de-differentiation and a burst in cell division and apoptosis. Double labeling experiments (in situ hybridization combined with TUNEL assay or with BrdU immunohistochemistry) suggest that both genes support cell proliferation, while survivin might also be involved in suppression of the programmed cell death.ConclusionsVisceral regeneration in the sea cucumber H. glaberrima is accompanied by elevated levels of cell division and cell death, and, moreover, involves expression of pro-cancer genes, such as survivin and mortalin, which are known to support proliferation and inhibit apoptosis. Nevertheless, once regeneration is completed and the expression pattern of both genes returns to normal, the regrown digestive tube shows no anomalies. This strongly suggests that sea cucumbers must possess some robust cancer-suppression mechanisms that allow rapid re-growth of the adult tissues without leading to runaway tumor development.

Risk Factors for Adenoidal Regrowth Among Patients in a Pediatric Allergy Practice

Hypertrophied adenoid glands are a common finding in pediatric patients with obstructive nasal symptoms. Recurrence of the symptoms following adenoidectomy is reported. One possible etiology for recurrent symptoms is regrowth of the adenoid tissue; however, prevalence of and risk factors for regrowth are not well delineated. The study was undertaken to determine the frequency of regrowth of adenoid tissue in a population of post-adenoidectomy patients presenting to a pediatric allergy office with obstructive nasal complaints, as well as to identify potential contributing risk factors in this population. Patients presenting with obstructive nasal symptoms, status post-adenoidectomy were retrospectively identified. Charts were reviewed for evidence of adenoid regrowth on imaging studies. A retrospective analysis was then performed comparing the presence and absence of adenoid regrowth with aeroallergen sensitivity, sinusitis, gastroesophageal reflux disease (GERD), tobacco exposure, asthma, and immunodeficiency disorders. One hundred and six patients’ histories were reviewed for this study. Forty-five percent of patients had evidence of adenoid regrowth on imaging studies, while 55% did not. The presence of GERD was more common in the group with adenoid regrowth (P = 0.012). Otherwise, the groups did not differ significantly. Among patients presenting with obstructive nasal symptoms following adenoidectomy, GERD was significantly more prevalent in those with regrowth of adenoid tissue.

Antibodies to wounded tissue enhance cutaneous wound healing

The wound repair process is a highly ordered sequence of events that encompasses haemostasis, inflammatory cell infiltration, tissue regrowth and remodelling. Wound healing follows tissue destruction so we hypothesized that antibodies might bind to wounded tissues, which would facilitate the engulfment of damaged tissues by macrophages. Here, we show that B cells, which produce antibodies to damaged tissues, are engaged in the process of wound healing. Splenectomy delayed wound healing, and transfer of spleen cells into splenectomized mice recovered the delay in wound healing. Furthermore, wound healing in splenectomized nude mice was also delayed. Transfer of enriched B220(+) cells by magnetic beads accelerated wound healing in splenectomized mice. We detected immunoglobulin G1 (IgG1) binding to wounded tissues by using fluorescein isothiocyanate-labelled anti-IgG1 6-24 hr after wounding. Splenectomy reduced the amount of IgG1 binding to wounded tissues. Immunoblotting studies revealed several bands, which were reduced by splenectomy. Using immunoprecipitation with anti-IgG bound to protein G we found that the intensity of several bands was lower in the serum from splenectomized mice than in that from sham-operated mice. These bands were matched to myosin IIA, carbamoyl-phosphate synthase, argininosuccinate synthase, actin and alpha-actinin-4 by liquid chromatography tandem mass spectrometry analysis.

Gene Delivery for Periodontal Tissue Engineering: Current Knowledge – Future Possibilities

The cellular and molecular events of periodontal healing are coordinated and regulated by an elaborate system of signaling molecules, pointing to a primary strategy for functional periodontal compartment regeneration to replicate components of the natural cellular microenvironment by providing an artificial extracellular matrix (ECM) and by delivering growth factors. However, even with optimal carriers, the localized delivery of growth factors often requires a large amount of protein to stimulate significant effects in vivo, which increases the risk and unwanted side effects. A simple and relatively new approach to bypassing this dilemma involves converting cells into protein producing factories. This is done by a so-called gene delivery method, where therapeutic agents to be delivered are DNA plasmids that include the gene encoding desired growth factors instead of recombinant proteins. As localized depots of genes, novel gene delivery systems have the potential to release their cargo in a sustained and controlled manner and finally provide time- and space- dependent levels of encoded proteins during all stages of tissue regrowth, offering great versatility in their application and prompting new tissue engineering strategy in periodontal regenerative medicine. However, gene therapy in Periodontology is clearly in its infancy. Significant efforts still need to be made in developing safe and effective delivery platforms and clarifying how gene delivery, in combination with tissue engineering, may mimic the critical aspects of natural biological processes occurring in periodontal development and repair. The aim of this review is to trace an outline of the state-of-the-art in the application of gene delivery and tissue engineering strategies for periodontal healing and regeneration.

Recovery of Porites cylindrica from the 2007-summer tissue loss at Shiraho, Ishigaki Island, Japan

Despite increased efforts in coral-reef monitoring and coral-disease research, reports on rapid recovery of diseased corals are rare. Here, I report fast recovery of Porites cylindrica colonies from live tissue loss, a reported and yet unnamed disease, at Shiraho, Ishigaki Island, Japan. Loss of live tissue and exposure of skeleton in P. cylindrica were first observed in August and September 2007. At the end of January 2008, recovery from the tissue loss was quantified. Mean proportion (±SD) of affected P. cylindrica branches decreased from 0.52±0.16 in September 2007 to 0.08±0.06 in January 2008. The majority of branches in the September sample had multiple, especially small, lesions; whereas in January, branches with multiple lesions were absent and most branches had no lesions. These results indicate that, by the end of January 2008, P. cylindrica colonies in the study area had almost fully recovered from the summer tissue loss by re-growth of live tissue over the denuded skeletons. Except in cases of coral bleaching, the rapid recovery from a disease observed in this study has not previously been reported. The observed quick recovery suggests that some coral-disease outbreaks may have been overlooked in the past and, without proper monitoring, will be overlooked in the future as well. Effects of overlooked diseases may accumulate and can have long-lasting impacts on reef communities, suggesting a need for frequent monitoring.

Pterygium Recurrence After Excision With Conjunctival Autograft: A Comparison of Fibrin Tissue Adhesive to Absorbable Sutures

To evaluate the rate of recurrence after pterygium excision with conjunctival autograft (CAG) using Tisseel fibrin tissue adhesive versus absorbable sutures. Forty-seven eyes of 42 patients who had undergone primary pterygium excision surgery with CAG were retrospectively reviewed. The study group, CAG adhered using Tisseel tissue adhesive (n = 27), were compared with the control group, CAG adhered using absorbable sutures (n = 20). Postoperative courses were followed for 22-36 months after surgery. Rates of recurrence were compared using logistic regression. Recurrence was defined as regrowth of fibrovascular tissue 1 mm past the corneoscleral limbus. The recurrence rate in the Tisseel group was 3.7% compared with 20% in the sutured group (P = 0.035). Recurrence rate in the Tisseel group was comparable to previously reported rates for CAG with sutures in the literature. There was a significant inverse relationship between age and rate of recurrence overall (P = 0.025). There was no difference in time to recurrence between the groups -- with an average time to recurrence of 3.13 months. In a predominantly Southern California population where there is an overall higher rate of pterygium recurrence, Tisseel tissue adhesive may improve surgical outcomes with equal to or lower long-term recurrence rates than previously reported.

The incidence of adenoidal regrowth after adenoidectomy and its effect on persistent nasal symptoms

Objective of the study is to evaluate the effectiveness of adenoidectomy for children, to asses the rates of adenoidal regrowth and find out if the regrowth of adenoidal tissue affects persistent nasal symptoms post-surgery. A prospective study was carried out in the period of 2005-2007. The inclusion criteria for patients in the study were hypertrophic adenoid tissue and moderate or severe persistent nasal obstruction. One hundred and fifty children had undergone an adenoidectomy using consistent technique and visual control. Medium-term follow-up results were conducted 12-24 months (the mean follow-up period was 17.1 months) post-surgery, performing transnasal fibroscopy and completing the questionnaire. A total of 104 (69.3%) out of 150 patients polled. Children's parents answered the questions that were used for the subjective assessment of symptoms and to ascertain the history of the patient's nasal obstruction and upper respiratory tract infection prior to surgery. The age range was from 3 to 15, of which, 68 (65.3%) of them had undergone a transnasal fibroscopy. There was a significant reduction in symptoms that were displayed by children prior to the operation: there were 5.8% patients with nasal obstruction after the surgery, while incidences of upper airway infections dropped from 79.8 to 7.7% after surgery (P < 0.001). Eighty-six (82.7%) parents considered their child's well-being as "having improved" and they were "satisfied" with the results. Transnasal fibroscopy examinations identified some regrowth of adenoidal tissue in 13 cases (19.1%), with only 3 cases demonstrating adenoidal regrowth to grade 1. Adenoidal regrowth was correlative with the age of the patients (P = 0.048) and to numerous postoperative treatment with antibiotics (P = 0.032). Adenoids rarely regrow after surgery and where there were traces of adenoidal tissue, it did not manifest clinically. Nasal obstruction after the adenoidectomy is rhinogenic origin, not the cause of enlarged adenoids. Adenoidal regrowth more often occurs in children younger than five years old and in those patients who were treated postoperatively with antibiotics on numerous occasions.

Curative Resection of Hepatic Alveolar Hydatids

An ultrasound examination of an asymptomatic 67-year-old German man during a routine medical consultation revealed two space-occupying lesions in the right lobe of the liver. Magnetic resonance imaging (MRI) located these two lesions to segment V and VII, respectively (Figure 1a, arrowheads), and hepatic malignancy or metastasis was suspected. MRI revealed no further lesions in the abdomen, lungs or brain. Endoscopy was unremarkable and tumor markers alpha-fetoprotein (AFP), carcinoembryogenic antigen (CEA), and cancer antigen (CA) 19-9 were within normal range. Serology was highly positive for Echinococcus multilocularis in a crude antigen-screening ELISA and in the confirmatory recombinant antigen-ELISA and immunoblot. Antiparasitic chemotherapy with albendazole (400 mg b.i.d.) was initiated, and the patient underwent hemihepatectomy and regional lymphadenectomy. Gross pathology of the resected liver tissue showed two adjacent alveolar lesions (Figure 1b), corresponding to the metacestode stage of E. multilocularis. Histological examination of the lesions demonstrated multiple eosinophilic vesicular structures surrounded by necrosis, fibrosis, and round cell infiltration (Figure 1c), a typical aspect of human alveolar echinococcosis. Based on to the World Health Organization’s staging system, we diagnosed stage II (P2N0M0). Albendazole therapy was well tolerated, and a 15-month followup period was uneventful. No regrowth of parasitic tissue could be detected on the follow-up MRI. Antibodies directed against a crude parasite antigen extract and the recombinant antigen Em10 showed a constant decline during the observation period (Figure 1d), which is consistent with a curative resection. Accordingly, immunoblot analysis of the first and last serum obtained showed a loss of one genus-specific band at 7 kDa and two speciesspecific bands at 16 and 18 kDa (Figure 1d, inset).

Immobilization of l-lysine on dense and porous poly(vinylidene fluoride) surfaces for neuron culture

Microporous poly(vinylidene fluoride) (PVDF) membranes with either dense or porous surface were prepared by isothermal immersion-precipitation of a casting solution in coagulation baths of different strengths. Onto the membrane surface, an amino acid (l-lysine) was immobilized by a dual-step chemical process. First, the membrane was grafted with poly(acrylic acid) (PAA) by means of plasma-induced free radical polymerization. Then, l-lysine was covalently bonded to the as-grafted PAA chains with the aid of a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC). The highest attainable graft yield of PAA on PVDF membrane reached up to 0.64 mg/cm 2. For immobilization of l-lysine on the membrane, the yields were found to depend on factors, such as concentration of EDC, activation time, and pH value. The maximal attainable immobilization yield was 0.65 μg/cm 2. Furthermore, pheochromocytoma (PC12) cells were cultured on l-lysine/PAA/PVDF membranes. It was found that both the amount of l-lysine on the membrane and the surface structure had a marked influence on the cell activity. Thus, the present results could be useful for the development of strategies to promote the re-growth and regeneration of tissue in the nervous system.

Efficacy and safety of a collagen matrix for cranial and spinal dural reconstruction using different fixation techniques

The use of dural grafts is frequently unavoidable when tension-free dural closure cannot be achieved following neurosurgical procedures or trauma. Biodegradable collagen matrices serve as a scaffold for the regrowth of natural tissue and require no suturing. The aim of this study was to investigate the efficacy and safety of dural repair with a collagen matrix using different fixation techniques. A total of 221 patients (98 male and 123 female; mean age 55.6 +/- 17.8 years) undergoing cranial (86.4%) or spinal (13.6%) procedures with the use of a collagen matrix dural graft were included in this retrospective study. The indications for use, fixation techniques, and associated complications were recorded. There were no complications of the dural graft in spinal use. Five (2.6%) of 191 patients undergoing cranial procedures developed infections, 3 of which (1.6%) were deep infections requiring surgical revision. There was no statistically significant relationship between the operative field status before surgery and the occurrence of a postoperative wound infection (p = 0.684). In the 191 patients undergoing a cranial procedure, cerebrospinal fluid (CSF) collection occurred in 5 patients (2.6%) and a CSF fistula in 5 (2.6%), 3 of whom (1.6%) required surgical revision. No patient who underwent an operation with preexisting CSF leakage had postoperative CSF leakage. Postoperative infection significantly increased the risk for postoperative CSF leakage. The collagen matrix was used without additional fixation in 124 patients (56.1%), with single fixation in 55 (24.9%), and with multiple fixations in 42 (19%). There were no systemic allergic reactions or local skin changes. Follow-up imaging in 112 patients (50.7%) revealed no evidence of any adverse reaction to the collagen graft. The collagen matrix is an effective and safe cranial and spinal dural substitute that can be used even in cases of an existing local infection. Postoperative deep infection increases the risk for CSF leakage.

In Situ Tissue Engineering of the Cricoid and Trachea in a Canine Model

The purpose of the current study was to demonstrate the efficacy of in situ tissue engineering of the cricoid and trachea in a canine model. Marlex mesh tube reinforced with polypropylene threads and covered by collagen sponge was used as a tissue scaffold for airway regeneration in 9 beagle dogs. The anterior half of the cricoid cartilage was resected in 5 dogs, whereas the cricoid cartilage and cervical trachea were simultaneously resected in 4 dogs. The tissue scaffold was implanted into the resultant defect. Endoscopic examination showed no airway obstruction for a postoperative period of 3 to 40 months in all dogs. Granulation tissue was observed in 2 dogs, and slight mesh exposure in 1 dog, although all were asymptomatic. Light microscopy and electron microscopy showed the endolaryngeal and endotracheal lumen to be covered by ciliated epithelium. According to strain-force measurement, the framework was firmly supported by regenerated tissue, as well as the normal cricoid and trachea. Our current tissue scaffold provides a rigid framework for the airway, and the collagen coating invites tissue regrowth around the tube. This study presents the possibility of successful reconstruction of the cricoid and trachea with epithelial regeneration by means of in situ tissue engineering.

Epithelial-Mesenchymal Transition and the Stem Cell Phenotype

Epithelial-mesenchymal transition (EMT) is a developmental process in which epithelial cells acquire the motile, migratory properties of mesenchymal cells. In a recent issue of Cell, Mani et al. (2008) show that induction of EMT stimulates cultured breast cells to adopt characteristics of stem cells.