Novel maxillary reconstruction with ectopic bone formation by GMP adipose stem cells

Microvascular reconstruction is the state-of-the-art in many fields of defect surgery today. Currently, reconstruction of large bony defects involves harvesting of autologous bone causing donor site morbidity and risk of infection. Specifically, utilizing autologous adipose stem cells (autoASCs), large quantities of cells can be retrieved for cell therapy applications and the risk of tissue rejection is diminished. The authors describe the first case report of a microvascular custom-made ectopic bone flap employing good manufacturing practice (GMP) level ASCs. The patient underwent a hemimaxillectomy due to a large keratocyst. After 36 months of follow-up, the defect was reconstructed with a microvascular flap using autoASCs, beta-tricalcium phosphate and bone morphogenetic protein-2. ASCs were isolated and expanded in clean room facilities according to GMP standards and were characterized in vitro. After 8 months of follow-up, the flap had developed mature bone structures and vasculature and was transplanted into the defect area. Postoperative healing has been uneventful, and further rehabilitation with dental implants has been started. The in vitro characterization demonstrated multipotentiality and mesenchymal stem cell characteristics in ASCs. This is the first clinical case where ectopic bone was produced using autoASCs in microvascular reconstruction surgery and it will pave way for new clinical trials in the field.

Spreading depression and focal brain ischemia induce cyclooxygenase-2 in cortical neurons through N-methyl-D-aspartic acid-receptors and phospholipase A2

Repetitive spreading depression (SD) waves, involving depolarization of neurons and astrocytes and up-regulation of glucose consumption, is thought to lower the threshold of neuronal death during and immediately after ischemia. Using rat models for SD and focal ischemia we investigated the expression of cyclooxygenase-1 (COX-1), the constitutive form, and cyclooxygenase-2 (COX-2), the inducible form of a key enzyme in prostaglandin biosynthesis and the target enzymes for nonsteroidal anti-inflammatory drugs. Whereas COX-1 mRNA levels were undetectable and uninducible, COX-2 mRNA and protein levels were rapidly increased in the cortex, especially in layers 2 and 3 after SD and transient focal ischemia. The cortical induction was reduced by MK-801, an N-methyl-D-aspartic acid-receptor antagonist, and by dexamethasone and quinacrine, phospholipase A2 (PLA2) inhibiting compounds. MK-801 acted by blocking SD whereas treatment with PLA2 inhibitors preserved the wave propagation. NBQX, an alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate-receptor antagonist, did not affect the SD-induced COX-2 expression, whereas COX-inhibitors indomethacin and diclofenac, as well as a NO synthase-inhibitor, NG-nitro-L-arginine methyl ester, tended to enhance the COX-2 mRNA expression. In addition, ischemia induced COX-2 expression in the hippocampal and perifocal striatal neurons and in endothelial cells. Thus, COX-2 is transiently induced after SD and focal ischemia by activation of N-methyl-D-aspartic acid-receptors and PLA2, most prominently in cortical neurons that are at a high risk to die after focal brain ischemia.

Dynamic piezoelectric stimulation enhances osteogenic differentiation of human adipose stem cells

This work reports on the influence of the substrate polarization of electroactive β-poly(vinylidene fluoride) (β-PVDF) on human adipose stem cells (hASCs) differentiation under static and dynamic conditions. hASCs were cultured on different β-PVDF surfaces (non-poled and "poled -") adsorbed with fibronectin and osteogenic differentiation was determined using a quantitative alkaline phosphatase assay. "Poled -" β-PVDF samples promote higher osteogenic differentiation, which is even higher under dynamic conditions. It is thus demonstrated that electroactive membranes can provide the necessary electromechanical stimuli for the differentiation of specific cells and therefore will support the design of suitable tissue engineering strategies, such as bone tissue engineering.

Long-term induction of haem oxygenase-1 (HSP-32) in astrocytes and microglia following transient focal brain ischaemia in the rat

Haem oxygenase-1 (HO-1) is a stress protein and a rate-limiting enzyme in haem degradation, generating ferrous iron, carbon monoxide and bile pigments. HO-1 has been suggested to be protective against oxidative stress. In the normal rodent brain the enzyme is localized in selected neuron populations, but heat shock, glutathione depletion in vivo and oxidative stress in vitro induce HO-1 predominantly in glial cells. We studied HO-1 expression in the brain following transient occlusion of the middle cerebral artery, and found increased mRNA levels in the ischaemic region from 4 h to 7 days after 90 min of ischaemia. The mRNA levels peaked at 12 h, and were localized perifocally. HO-1-immunoreactive astrocytes and microglial cells were seen in the perifocal area, in the ipsilateral and occasionally in the contralateral hippocampus. Some perifocal neurons were also HO-1-immunoreactive. In the infarcted area HO-1-positive microglia/macrophages were detected in double-labelling experiments. A microassay measuring the conversion of [14C]haem to [14C]bilirubin showed a two-fold increase in haem oxygenase activity in the infarcted core. These observations show a long-term induction of HO-1 protein and its activity following ischaemia-reperfusion brain injury, and indicate increased capacity for haem degradation and the generation of biologically active bile products, carbon monoxide and iron in astrocytes and some microglia/macrophages during focal brain ischaemia.

Biological and immunological relations among human parvovirus B19 genotypes 1 to 3

The human parvovirus B19 is now divided into three genotypes: type 1 (prototype), type 2 (A6- and LaLi-like), and type 3 (V9-like). In overall DNA sequence, the three virus types differ by approximately 10%. The most striking DNA dissimilarity, of >20%, is observed within the p6 promoter region. Because of the scarcity of data on the biological activities and pathogenetic potentials of virus types 2 and 3, we examined the functional characteristics of these virus types. We found the activities of the three p6 promoters to be of equal strength and to be most active in B19-permissive cells. Virus type 2 capsid protein VP2, alone or together with VP1, was expressed with the baculovirus system and was shown to assemble into icosahedral parvovirus-like particles, which were reactive in the hemagglutination assay. Furthermore, sera containing DNA of any of the three B19 types were shown to hemagglutinate. The infectivities of these sera were examined in two B19-permissive cell lines. Reverse transcription-PCR revealed synthesis of spliced B19 mRNAs, and immunofluorescence verified the production of NS and VP proteins in the infected cells. All three genotypes showed similar functional characteristics in all experiments performed, showing that the three virus types indeed belong to the same species, i.e., human parvovirus B19. Additionally, the antibody activity in sera from B19 type 1- or type 2-infected subjects (long-term immunity) was examined with homo- and heterologous virus-like particles. Cross-reactivity of 100% was observed, indicating that the two B19 genotypes comprise a single serotype.

Osteogenic medium is superior to growth factors in differentiation of human adipose stem cells towards bone-forming cells in 3D culture

Human adipose stem cells (hASCs) have been recently used to treat bone defects in clinical practice. Yet there is a need for more optimal scaffolds and cost-effective approaches to induce osteogenic differentiation of hASCs. Therefore, we compared the efficiency of bone morphogenetic proteins (BMP-2 and BMP-7), vascular endothelial growth factor (VEGF), and osteogenic medium (OM) for the osteo-induction of hASCs in 3D culture. In addition, growth factors were tested in combination with OM. Commercially available bioactive glass scaffolds (BioRestore) and biphasic calcium phosphate granules (BoneCeramic) were evaluated as prospective carriers for hASCs. Both biomaterials supported hASC-viability, but BioRestore resulted in higher cell number than BoneCeramic, whereas BoneCeramic supported more significant collagen production. The most efficient osteo-induction was achieved with plain OM, promoting higher alkaline phosphatase activity and collagen production than growth factors. In fact, treatment with BMP-2 or VEGF did not increase osteogenic differentiation or cell number significantly more than maintenance medium with either biomaterial. Moreover, BMP-7 treatment consistently inhibited proliferation and osteogenic differentiation of hASCs. Interestingly, there was no benefit from growth factors added to OM. This is the first study to demonstrate that OM enhances hASC-differentiation towards bone-forming cells significantly more than growth factors in 3D culture.

Comparative analysis of COVID-19 vaccine responses and third booster dose-induced neutralizing antibodies against Delta and Omicron variants

Two COVID-19 mRNA (of BNT162b2, mRNA-1273) and two adenovirus vector vaccines (ChAdOx1 and Janssen) are licensed in Europe, but optimization of regime and dosing is still ongoing. Here we show in health care workers (n = 328) that two doses of BNT162b2, mRNA-1273, or a combination of ChAdOx1 adenovirus vector and mRNA vaccines administrated with a long 12-week dose interval induce equally high levels of anti-SARS-CoV-2 spike antibodies and neutralizing antibodies against D614 and Delta variant. By contrast, two doses of BNT162b2 with a short 3-week interval induce 2-3-fold lower titers of neutralizing antibodies than those from the 12-week interval, yet a third BNT162b2 or mRNA-1273 booster dose increases the antibody levels 4-fold compared to the levels after the second dose, as well as induces neutralizing antibody against Omicron BA.1 variant. Our data thus indicates that a third COVID-19 mRNA vaccine may induce cross-protective neutralizing antibodies against multiple variants.

Vitamin D and prostate cancer

Our recent epidemiological study (Ahonen et al., Cancer Causes Control 11(2000) (847-852)) suggests that vitamin D deficiency may increase the risk of initiation and progression of prostate cancer. The nested case-control study was based on a 13-year follow-up of about 19000 middle-aged men free of clinically verified prostate cancer. More than one-half of the serum samples had 25OH-vitamin D (25-VD) levels below 50 nmol/l, suggesting VD deficiency. Prostate cancer risk was highest among the group of younger men (40-51 years) with low serum 25-VD, whereas low serum 25-VD appeared not to increase the risk of prostate cancer in older men (>51 years). This suggests that VD has a protective role against prostate cancer only before the andropause, when serum androgen concentrations are higher. The lowest 25-VD concentrations in the younger men were associated with more aggressive prostate cancer. Furthermore, the high 25-VD levels delayed the appearance of clinically verified prostate cancer by 1.8 years. Since these results suggest that vitamin D has a protective role against prostate cancer, we tried to determine whether full spectrum lighting (FSL) during working hours could increase serum 25-VD concentrations. After 1-month exposure, there was no significant increase in the serum 25-VD level, although there was a bias towards slightly increasing values in the test group as opposed to decreasing values in controls. There was no significant change in the skin urocanic acid production. The possibility to use FSL in cancer prevention is discussed. In order to clarify the mechanism of VD action on cell proliferation and differentiation, we performed studies with the rat and human prostates as well prostate cancer cell lines. It is possible that 25-VD may have a direct role in the host anticancer defence activity, but the metabolism of vitamin D in the prostate may also play an important role in its action. We raised antibodies against human 1alpha-hydroxylase and 24-hydroxylase. Our preliminary results suggest that vitamin D is actively metabolised in the prostate. Vitamin D appears to upregulate androgen receptor expression, whereas androgens seem to upregulate vitamin D receptor (VDR). This may at least partially explain the androgen dependence of VD action. VD alone or administered with androgen causes a suppression of epithelial cell proliferation. VD can activate mitogen-activated kinases, erk-1 and erk-2, within minutes and p38 within hours. Also, auto/paracrine regulation might be involved, since keratinocyte growth factor (mRNA and protein) was clearly induced by VD. Based on these studies, a putative model for VD action on cell proliferation and differentiation is presented.

Expression of all six human Torque teno virus (TTV) proteins in bacteria and in insect cells, and analysis of their IgG responses

Torque teno virus (TTV) is a non-enveloped human virus with a circular ( approximately 3800 nt) ssDNA genome. TTV transcription results in three viral mRNAs and six proteins, the function or antigenicity of which are unknown. The six open reading frames of TTV genotype 6 were expressed in bacteria and insect cells. Expression of the ORF1/1-encoded protein was inefficient, while expression of the others was successful, with ORF1 and ORF1/2 as arginine-rich region depleted. All six recombinant TTV proteins were antigenic. Of healthy adults, 11/25 (44%) showed strong IgG reactivity with one or more proteins. Four subjects, two of whom were genotype-6-DNA positive, were followed. One of the latter showed concurrently a strong IgG response against the ORF1 protein. The other showed appearance of IgG against the ORF2 protein concomitantly with resolution of the genotype-6 viremia. The genotype-6 sequences remained unaltered for years, suggesting that some mechanisms other than amino acid substitutions play a role in TTV immune evasion.

Radiotherapy enhanced ototoxicity of cisplatin in children

We reviewed and re-examined 31 children (6 months-14 years at the time of diagnosis), who had been treated for a neoplasm in Turku University Central Hospital between 1989 and 1994. The children were divided into 3 groups according to the site of the neoplasm and the type of therapy. Group I included 13 children, operated on for an intracranial tumor and received postoperative radio- and cisplatin-based chemotherapy. Group II included 14 children operated on for intracranial tumors and treated with radiotherapy, but not given chemotherapy. Group III included 4 children suffering from extracranial malignancies and they had received chemotherapy including cisplatin. The children in Group I had significantly worse hearing thresholds in the middle- and high-frequency range than children in Groups II and III. In a precise analysis of the different factors, no single dose of cisplatin, inner ear irradiation dose or totally to the central nervous system (CNS) received irradiation dose correlated to the detected hearing loss. However, multiple linear correlation analyses suggest a combined effect of radiotherapy plus cisplatin resulting in a high frequency hearing loss. This is in accordance with earlier random case reports, and supports the idea that radiotherapy should be considered cautiously in children treated with cisplatin for intracranial malignancies.

Loss-of-function mutation in IKZF2 leads to immunodeficiency with dysregulated germinal center reactions and reduction of MAIT cells

[Figure: see text].

Effect of florfenicol on the immune response of rainbow trout (Oncorhynchus mykiss)

Florfenicol, a drug effective against several bacterial diseases of fish, was tested for possible immunomodulatory effects. The aim of the study was to follow the kinetics of the immune response after vaccination with simultaneous oral antibiotic treatment. The fish were immunised with a commercial oil-based divalent (furunculosis/vibriosis) vaccine and were simultaneously given oral antibiotic treatment. The specific immune response was monitored by analysing the levels of specific antibodies with ELISA. As an indicator of the non-specific immune response the phagocytic activity of circulating leucocytes was measured by a chemiluminescence assay. Total circulating leucocyte counts and differentials were also monitored. The disease resistance was evaluated by challenge tests at the end of the experiment. The results showed that florfenicol did not have any significant effect on antibody production and circulating leucocyte levels but caused a suppression in chemiluminescence response/phagocytic cell 5-6 weeks after vaccination. The survival after challenge was slightly suppressed by the florfenicol treatment. The RPS-value for the vaccinated group was 98% and for the florfenicol-treated group was 88%.

Bioactive glass induced osteogenic differentiation of human adipose stem cells is dependent on cell attachment mechanism and mitogen-activated protein kinases

Bioactive glasses (BaGs) are widely utilised in bone tissue engineering (TE) but the molecular response of cells to BaGs is poorly understood. To elucidate the mechanisms of cell attachment to BaGs and BaG-induced early osteogenic differentiation, we cultured human adipose stem cells (hASCs) on discs of two silica-based BaGs S53P4 (23.0 Na2O - 20.0 CaO - 4.0 P2O5 - 53.0 SiO2 (wt-%)) and 1-06 (5.9 Na2O - 12.0 K2O - 5.3 MgO - 22.6 CaO - 4.0 P2O5 - 0.2 B2O3 - 50.0 SiO2) in the absence of osteogenic supplements. Both BaGs induced early osteogenic differentiation by increasing alkaline phosphatase activity (ALP) and the expression of osteogenic marker genes RUNX2a and OSTERIX. Based on ALP activity, the slower reacting 1-06 glass was a stronger osteoinducer. Regarding the cell attachment, cells cultured on BaGs had enhanced integrinβ1 and vinculin production, and mature focal adhesions were smaller but more dispersed than on cell culture plastic (polystyrene). Focal adhesion kinase (FAK), extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK)-induced c-Jun phosphorylations were upregulated by glass contact. Moreover, the BaG-stimulated osteoinduction was significantly reduced by FAK and mitogen-activated protein kinase (MAPK) inhibitors, indicating an important role for FAK and MAPKs in the BaG-induced early osteogenic commitment of hASCs. Upon indirect insert culture, the ions released from the BaG discs could not reproduce the observed cellular changes, which highlighted the role of direct cell-BaG interactions in the osteopotential of BaGs. These findings gave valuable insight into the mechanism of BaG-induced osteogenic differentiation and therefore provided knowledge to aid the future design of new functional biomaterials to meet the increasing demand for clinical bone TE treatments.

Vitamin D induced up-regulation of keratinocyte growth factor (FGF-7/KGF) in MCF-7 human breast cancer cells

Keratinocyte growth factor (FGF-7/KGF) is a secreted member of the fibroblast growth factor family, which functions primarily as an important paracrine mediator of cell growth and differentiation. Inhibitory pathways of vitamin D may also involve participation of some growth factors. To determine whether vitamin D may play a role in the expression of FGF-7, we investigated FGF-7 expression in human breast cancer cells treated with 1,25-dihydroxyvitamin D3, which inhibited the growth of the cells. By means of cDNA microarray, RT-PCR, and Western blot analysis, we have shown an increase in expression of FGF-7 on both mRNA and protein levels after vitamin D exposure. This is the first demonstration of vitamin D regulation of FGF-7 expression and its possible involvement in mediating growth and differentiation by vitamin D.

Construction and biological activity of a full-length molecular clone of human Torque teno virus (TTV) genotype 6

Torque teno virus (TTV) is a non-enveloped human virus with a circular negative-sense (approximately 3800 nucleotides) ssDNA genome. TTV resembles in genome organization the chicken anemia virus, the animal pathogen of the Circoviridae family, and is currently classified as a member of a new, floating genus, Anellovirus. Molecular and cell biological research on TTV has been restricted by the lack of permissive cell lines and functional, replication-competent plasmid clones. In order to examine the key biological activities (i.e. RNA transcription and DNA replication) of this still poorly characterized ssDNA virus, we cloned the full-length genome of TTV genotype 6 and transfected it into cells of several types. TTV mRNA transcription was detected by RT-PCR in all the cell types: KU812Ep6, Cos-1, 293, 293T, Chang liver, Huh7 and UT7/Epo-S1. Replicating TTV DNA was detected in the latter five cell types by a DpnI-based restriction enzyme method coupled with Southern analysis, a novel approach to assess TTV DNA replication. The replicating full-length clone, the cell lines found to support TTV replication, and the methods presented here will facilitate the elucidation of the molecular biology and the life cycle of this recently identified human virus.

The vitamin D neuroendocrine system as a target for novel neurotropic drugs

Vitamin D is a seco-steroid hormone with multiple functions in the nervous system. Physiological brain mechanisms of vitamin D and its receptors include neuroprotection, antiepileptic effects, immunomodulation, possible interplay with several brain neurotransmitter systems and hormones, as well as the regulation of behaviours. Here we review the important role of the vitamin D neuroendocrine system in the brain, and outline perspectives for the search for novel neurotropic drugs to treat various vitamin D-related dysfunctions.

ERCC6 founder mutation identified in Finnish patients with COFS syndrome

Cerebro-oculo-facio-skeletal (COFS) syndrome is an autosomal recessive disorder characterized by microcephaly, congenital cataracts, facial dysmorphism, neurogenic arthrogryposis, growth failure and severe psychomotor retardation. We report a large consanguineous pedigree from northern Finland with six individuals belonging into four different sibships and affected with typical COFS syndrome phenotype. Two deceased patients have been published previously in 1982 as the first cases exhibiting cerebral calcifications typical for this disorder. Two living and one of the deceased patients were all shown to possess a novel homozygous mutation in the ERCC6 [Cockayne syndrome B (CSB)] gene, thereby confirming the diagnosis on molecular genetic level even for the earlier published cases. Genealogical investigation showed a common ancestor living in a northeastern village in Finland in the 18th century for all six patients implying a founder effect.

Cochleovestibular symptoms related to the site of vestibular schwannoma

The purpose of the investigation was to study the symptoms that may provide clues to the early diagnosis of vestibular schwannoma (VS). The symptoms associated with VS in 41 patients were compared with the tumour locations detected by magnetic resonance imaging (MRI). There were 9 (22%) mainly intracanalicular and 32 (78%) mainly extracanalicular tumours. MRI visualized the enhancement of the intracanalicular nerve in 27 of 32 extracanalicular schwannomas. Hearing impairment was found as an initial symptom equally frequently in patients with intra- or extracanalicular VS. Tinnitus was reported as the first symptom more often in patients with extracanalicular VS and dizziness more often in patients with intracanalicular tumours. At the time of diagnosis, unilateral hearing loss was present in 98% of patients, independent of tumour location. Likewise, dizziness was found equally frequently in both patient groups. Instead, tinnitus was found almost significantly more frequently in patients with intracanalicular VS (p = 0.07). Although statistically insignificantly so, neurological symptoms were more common in patients with extracanalicular VS (p = 0.45).

Human parainfluenza virus type 2 (HPIV2) induced host ADAM8 expression in human salivary adenocarcinoma cell line (HSY) during cell fusion

BACKGROUND

The aim of the study was to investigate expression of ADAMs (A Disintegrin and A Metalloproteinase) of host cell origin during cell-cell fusion induced by human parainfluenza virus type 2 (HPIV2).

RESULTS

Induction of host cell ADAM9 was observed in GMK cells, but the applicability of this model was restricted by lack of cross-reactivity of the anti-human ADAM8 antibodies with the corresponding green monkey antigens. HSG cells were not susceptible to HPIV2 virus infection. In contrast, in human parotid gland HSY cells, a natural host cell for paramyxoviruses, HPIV2 induced ADAM8 expression. ADAM8 staining increased dramatically over time from 7.9 +/- 3% at zero hours to 99.2 +/- 0.8% at 72 hours (p = 0.0001). Without HPIV2 the corresponding percentages were only 7.7% and 8.8%. Moreover, ADAM8 positive cells formed bi- (16.2%) and multinuclear cells (3.5%) on day one and the corresponding percentages on day three were 15.6% for binuclear and 57.2% for multinuclear cells.

CONCLUSION

ADAM8, well recognized for participation in cell-to-cell fusion especially in osteoclast formation, is up-regulated upon formation of multinuclear giant cells after HPIV2 induction in HSY cells. The virus-HSY cell system provides a novel experimental model for study of the molecular mechanism of cell fusion events.

A Highly Sensitive and Specific SARS-CoV-2 Spike- and Nucleoprotein-Based Fluorescent Multiplex Immunoassay (FMIA) to Measure IgG, IgA, and IgM Class Antibodies

Validation and standardization of accurate serological assays are crucial for the surveillance of the coronavirus disease 2019 (COVID-19) pandemic and population immunity. We describe the analytical and clinical performance of an in-house fluorescent multiplex immunoassay (FMIA) for simultaneous quantification of antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleoprotein and spike glycoprotein. Furthermore, we calibrated IgG-FMIA against World Health Organization (WHO) International Standard and compared FMIA results to an in-house enzyme immunoassay (EIA) and a microneutralization test (MNT). We also compared the MNT results of two laboratories. IgG-FMIA displayed 100% specificity and sensitivity for samples collected 13 to 150 days post-onset of symptoms (DPO). For IgA- and IgM-FMIA, 100% specificity and sensitivity were obtained for a shorter time window (13 to 36 and 13 to 28 DPO for IgA- and IgM-FMIA, respectively). FMIA and EIA results displayed moderate to strong correlation, but FMIA was overall more specific and sensitive. IgG-FMIA identified 100% of samples with neutralizing antibodies (NAbs). Anti-spike IgG concentrations correlated strongly (ρ = 0.77 to 0.84, P < 2.2 × 10-16) with NAb titers, and the two laboratories' NAb titers displayed a very strong correlation (ρ = 0.95, P < 2.2 × 10-16). Our results indicate good correlation and concordance of antibody concentrations measured with different types of in-house SARS-CoV-2 antibody assays. Calibration against the WHO international standard did not, however, improve the comparability of FMIA and EIA results. IMPORTANCE SARS-CoV-2 serological assays with excellent clinical performance are essential for reliable estimation of the persistence of immunity after infection or vaccination. In this paper we present a thoroughly validated SARS-CoV-2 serological assay with excellent clinical performance and good comparability to neutralizing antibody titers. Neutralization tests are still considered the gold standard for SARS-CoV-2 serological assays, but our assay can identify samples with neutralizing antibodies with 100% sensitivity and 96% specificity without the need for laborious and slow biosafety level 3 (BSL-3) facility-requiring analyses.

Induction of ornithine decarboxylase mRNA in transient focal cerebral ischemia in the rat

We used in situ hybridization to localize the long-term changes in ornithine decarboxylase (ODC) expression after a 90 min occlusion of the middle cerebral artery (MCAO) in the rat. The ODC mRNA was induced in the ipsilateral dentate gyrus (DG) and throughout the ischemic cortex at 12 h and still at 3 days after reperfusion. The induction was blocked by an N-methyl-D-aspartate (NMDA) receptor antagonist suggesting that ODC induction is NMDA receptor-mediated. The long-lasting up-regulation detected in regions where no cellular damage usually occurs, favors the hypothesis that ODC expression does not contribute to neuronal death after stroke.

Chitosan membranes in a rat model of full-thickness cutaneous wounds: healing and IL-4 levels

OBJECTIVE

The aim of this study was to examine the effect of chitosan membrane on wound healing.

METHOD

The effect of chitosan membranes was evaluated in an experimental rat model. On day 0, circular full-thickness skin sections were excised from the scalps of rats. The wounds were then measured and the surrounding area tattooed. Rats were sacrificed either immediately after excision, or randomised into control and chitosan groups and followed up on day 3, 7, 14 or 21. Control group wounds were covered with Aquacel (wound dressing). Chitosan group wounds were covered with chitosan membranes and the wound dressing. Wounds and the distances between the tattooed marks were measured on follow-up, the wound sites were harvested and histologically examined, and serum interleukin (IL-4) levels were analysed.

RESULTS

A total of 54 rats were examined and all time points included 6 control and 6 chitosan treated animals, except for day 0 which consisted of control animals only. On day 3, wounds in the chitosan group were significantly (p<0.05) smaller (60±6% versus 78±19% of the original wound area) than in the control group. Chitosan membranes were found to degrade at the wound sites between days 7 and 14. Leukocyte counts were lower in the chitosan group than in the control group on day seven (p<0.05). IL-4 levels were significantly higher on day 7 (p<0.001) and 14 (p<0.001) in the chitosan group.

CONCLUSION

According to our results chitosan membrane may promote early wound healing, reduce inflammation and affect the IL-4 pathway, however, the membrane degrades at the wound site after day 7.

Cell adhesion and culture medium dependent changes in the high frequency mechanical vibration induced proliferation, osteogenesis, and intracellular organization of human adipose stem cells

High frequency (HF) mechanical vibration appears beneficial for in vitro osteogenesis of mesenchymal stem cells (MSCs). However, the current mechanobiological understanding of the method remains insufficient. We designed high-throughput stimulators to apply horizontal or vertical high magnitude HF (HMHF; 2.5 G_peak, 100 Hz) vibration on human adipose stem cells (hASCs). We analyzed proliferation, alkaline phosphatase (ALP) activity, mineralization, and effects on the actin cytoskeleton and nuclei using immunocytochemical stainings. Proliferation was studied on a standard tissue culture plastic (sTCP) surface and on an adhesion supporting tissue culture plastic (asTCP) surface in basal (BM) and osteogenic (OM) culture medium conditions. We discovered that the improved cell adhesion was a prerequisite for vibration induced changes in the proliferation of hASCs. Similarly, the adhesion supporting surface enabled us to observe vibration initiated ALP activity and mineralization changes in OM condition. The horizontal vibration increased ALP activity, while vertical stimulation reduced ALP activity. However, mineralization was not enhanced by the HMHF vibration. We performed image-based analysis of actin and nuclei to obtain novel data of the intracellular-level responses to HF vibration in BM and OM conditions. Our quantitative results suggest that actin organizations were culture medium and stimulation direction dependent. Both stimulation directions decreased OM induced changes in nuclear size and elongation. Consequently, our findings of the nuclear deformations provide supportive evidence for the involvement of the nuclei in the mechanocoupling of HF vibration. Taken together, the results of this study enhanced the knowledge of the intracellular mechanisms of HF vibration induced osteogenesis of MSCs.

Blood flow-independent accumulation of cisplatin in the guinea pig cochlea

Considerable interindividual variability in the ototoxic effect of cisplatin has become the unpredictable dose-limiting factor in its use as curative as well as palliative therapy. The drug accumulates in highly vascular areas in the cochlea, causing dose-related hair cell loss. The purpose of this study was to assess blood flow-dependent aspects of cisplatin absorption in the cochlea in order to better understand factors that may influence cisplatin-induced ototoxicity. The effect of reduced cochlear blood flow on the ototoxic action of cisplatin was studied in guinea pigs. Before cisplatin administration the cochlear vasculature in each animal was unilaterally pre-constricted, by the application of 2% epinephrine to the round window. A 20-30% reduction in cochlear blood flow, assessed by laser Doppler flowmetry, was maintained before and after intravenous infusion of 0.1% cisplatin. Cisplatin infusion affected cochlear blood flow but not vessel conductivity. The cochlear blood flow decrease, maintained by local epinephrine application to the round window during cisplatin infusion, did not alter the cisplatin-induced hearing loss. In addition, the concentration of free cisplatin in scala tympani perilymph did not differ between epinephrine-treated and non-treated ears. Our results indicate that cisplatin transport into the cochlea is not an energy-dependent process in the lateral wall vasculature.