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Biomedical subjects

E Kallio

Publications and source records attributed to E Kallio.

At least 19 recordsLinked to original sources
PubMed2006

Plasma acceleration above martian magnetic anomalies.

Auroras are caused by accelerated charged particles precipitating along magnetic field lines into a planetary atmosphere, the auroral brightness being roughly proportional to the precipitating particle energy flux. The Analyzer of Space Plasma and Energetic Atoms experiment on the Mars Express spacecraft has made a detailed study of acceleration processes on the nightside of Mars. We observed accelerated electrons and ions in the deep nightside high-altitude region of Mars that map geographically to interface/cleft regions associated with martian crustal magnetization regions. By integrating electron and ion acceleration energy down to the upper atmosphere, we saw energy fluxes in the range of 1 to 50 milliwatts per square meter per second. These conditions are similar to those producing bright discrete auroras above Earth. Discrete auroras at Mars are therefore expected to be associated with plasma acceleration in diverging magnetic flux tubes above crustal magnetization regions, the auroras being distributed geographically in a complex pattern by the many multipole magnetic field lines extending into space.

Journal Article↗
PubMed2004

Solar wind-induced atmospheric erosion at Mars: first results from ASPERA-3 on Mars Express.

The Analyzer of Space Plasma and Energetic Atoms (ASPERA) on board the Mars Express spacecraft found that solar wind plasma and accelerated ionospheric ions may be observed all the way down to the Mars Express pericenter of 270 kilometers above the dayside planetary surface. This is very deep in the ionosphere, implying direct exposure of the martian topside atmosphere to solar wind plasma forcing. The low-altitude penetration of solar wind plasma and the energization of ionospheric plasma may be due to solar wind irregularities or perturbations, to magnetic anomalies at Mars, or both.

Journal Article↗
PubMed2004

Boron uptake by ectomycorrhizas of silver birch.

Boron (B) is an essential micronutrient for plants but it is thought not to be essential for fungi. We studied whether the extraradical mycelia of Paxillus involutus in symbiosis with silver birch (Betula pendula) take up B and transport it to the host plant. We grew mycorrhizal plants in flat microcosms with a partitioning wall, below which there was only extraradical mycelium. A boric acid solution enriched in 10B was applied to these mycelia. Increased 10B/11B isotope ratios were subsequently measured in birch leaves, stems, and roots plus mycorrhizas in the upper compartment. Boron was therefore taken up by the mycorrhizal mycelia and transported to the host plant in this species combination.

Basidiomycota↗
PubMed1999

Differentiation and maturation of porcine fetal islet cells in vitro and after transplantation.

BACKGROUND: Porcine fetal pancreas is a potential source of beta cells for transplantation. The immaturity of the cells is a problem. We have defined the optimal conditions for in vitro propagation of this tissue before transplantation. METHODS: Porcine fetal pancreas tissue was obtained for tissue culture at various stages of development. Serum-containing and serum-free media and a variety of potential differentiation factors were tested. In vitro, the numbers of endocrine islet cells and their proliferation were quantified and functional maturity of the beta cells was assessed by perifusion. Growth and maturation of the cells was assessed 3 months after transplantation into nude mice. RESULTS: Highest beta cell mass was obtained from end-gestational, as compared with early fetal or neonatal, pancreas. Nicotinamide and sodium butyrate effectively increased the insulin content and the number of endocrine cells in culture. In combination, these factors led up to a 90-fold increase in the insulin content of islet-like cell clusters (ICC) as compared with untreated controls. However, a high level of cell death through apoptosis was observed in these maximally stimulated endocrine cells, and they did not survive as grafts when transplanted into nude mice. Instead, a serum-free culture medium containing 10 mM nicotinamide and 0.1 mM isobutylmethylxanthine was found to support both differentiation and proliferation of endocrine cells as loose ICCs. Insulin release from these ICCs was sensitive to glucose. When transplanted under the kidney capsule of normoglycemic nude mice, a high level of beta cell differentiation and function was evident only in the ICCs cultured in the serum-free medium, and in freshly isolated ICCs. When transplanted to hyperglycemic nude recipients, the cells cultured in serum-free medium for 3 weeks reversed hyperglycemia more consistently and rapidly than freshly isolated ICCs. CONCLUSIONS: Optimal maturation of porcine fetal pancreatic cells is obtained in serum-free medium supplemented with nicotinamide. Butyrate is a potent stimulus for beta cell differentiation but leads to increased apoptotic cell death.

Animals↗
PubMed1996

Lack of effect of recombinant human superoxide dismutase on cold ischemia-induced arteriosclerosis in syngeneic rat aortic transplants.

Prolonged cold ischemia time and the generation of free oxygen radicals during reperfusion are risk factors for allograft arteriosclerosis. Growth factors are the main pro-proliferative mediators of smooth muscle cells in classical and in allograft arteriosclerosis. Superoxide dismutase is an enzyme that catalyzes the dismutation of superoxide anions into hydrogen peroxide. This study was designed to investigate which smooth muscle cell growth factor contribute to the formation of arteriosclerosis in syngenic vascular grafts with prolonged ischemia time, and whether perioperative intravenous administration of recombinant human superoxide dismutase (rh-SOD) prevents arteriosclerosis in these grafts. DA aortas were transplanted into DA recipients. One group of transplants was made with a short ex vivo ischemia time (15 min), while the other group transplant grafts was stored for 24 hr in cold saline. In addition to morphometric quantitation of the histological alterations, RNA isolated from grafts with short cold ischemia time in a semiquantitative polymerase chain reaction specific for various known smooth muscle cell growth factors. Syngeneic grafts with prolonged cold ischemia time showed severe intimal thickening and prominent medical necrosis, which were not seen in control groups. Approximately 3-fold levels of insulin-like growth factor-1 were found in ischemic syngeneic grafts compared with non-ischemic syngenic grafts, whereas epidermal growth factor levels were slightly lower. No changes in other growth factor mRNAs were found. Perioperative treatment with rh-SOD did not have significant effect on the extent of intimal thickening nor on the intensity of medial necrosis in grafts with prolonged ischemia time, and administration of rh-SOD did not change the expression level of insulin-like growth factor-1 in the grafts, either.

Animals↗
PubMed1996

Rat cytomegalovirus infection and chronic kidney allograft rejection.

To investigate the effect of cytomegalovirus (CMV) infection on the development of experimental chronic kidney allograft rejection, orthotopic kidney allografts from DA donors (Ag-B4, RT1a1) to WF (Ag-B2, RT1u) recipients were used. The rats received cyclosporine A (CsA) for 12 weeks. A group of recipients was infected with 10(5) plaque-forming units of rat CMV (RCMV), and another group was left non-infected and used as controls. The grafts were removed 12 weeks after transplantation. RCMV infection significantly enhanced the development of chronic kidney allograft rejection as follows: the intensity of interstitial inflammation (P < 0.025), particularly the degree of pyroninophilic cells in the inflammatory infiltrate (P < 0.025); the glomeruli mesangial matrix increase (P < 0.05) and capillary basement membrane thickening (P < 0.01); the extent of endothelial cell swelling (P < 0.025) and intimal proliferation (P < 0.025) in the graft vasculature; and the extent of tubular epithelial atrophy (P < 0.025). The chronic allograft damage index (CADI) was significantly increased to 4.2 +/- 0.9 in RCMV-infected allografts, compared with 0.8 +/- 0.4 in non-infected (P < 0.02). At the molecular level, RCMV infection significantly increased vascular endothelial (P < 0.05) and tubular epithelial (P < 0.01) ICAM-1 expression. Viral antigens were detected in tubular epithelial cells and in some inflammatory cells.

Animals↗
PubMed1996

Cytomegalovirus infection accelerates obliterative bronchiolitis of rat tracheal allografts.

A cascade of inflammation and injury of the airway wall followed by a fibroproliferative process that results in airway obstruction has been suggested as the explanation of the process of obliterative bronchiolitis (OB) in lung allograft recipients. To determine the impact of rat cytomegalovirus (RCMV) infection on the development of OB, heterotopic rat tracheal allografts were transplanted from DA donors to WF recipients immunosuppressed with 2 mg/kg per day cyclosporine A. Chronic RCMV infection was similarly established 8 weeks before transplantation in donors alone (D+/R-), recipients alone (D-/R+), and both donors and recipients (D+/R+). The control rats were left non-infected, but were similarly immunosuppressed. The results of this study demonstrate that both acute and chronic recipient RCMV infection, but not donor infection, amplify the development of experimental OB in the rat and suggest that RCMV infection-associated immune response, rather than the viral load in the graft, is essential for the development of the accelerated form of OB.

Animals↗
PubMed1996

Production oriented method for the determination of rare earth and other trace elements in rocks by ICP-MS.

The rare earth elements along with Y, Sc, Co, Hf, Nb, Rb, Ta, Th, Ti, U, V and Zr have been determined in ten standard reference materials and ten granitoid samples by inductively coupled plasma mass spectrometry (ICP-MS). Two digestion methods have been used: (a) dissolution with hydrofluoric-perchloric acid followed by fusion of the residue with lithium metaborate, (b) dissolution with hydrofluoric acid-perchloric acid followed by fusion with lithium metaboratesodium perborate and addition of hydrogen peroxide. An evaluation of the two decomposition methods and a comparison of the ICP-MS and X-ray fluorescence results have been carried out. In comparing the two digestion methods, method (b) gave more accurate results for Nb and Ta, and it has been applied to a rock geochemistry project covering whole Finland (about 7000 samples). The statistical stability of the method has been monitored by frequent analyses of reference material SDC-1 (Mica Schist, USGS).

Journal Article↗
PubMed1996

Cytomegalovirus infection-enhanced chronic kidney allograft rejection is linked with intercellular adhesion molecule-1 expression.

In human kidney allografts, association of acute rejection and glomerulopathy with cytomegalovirus (CMV) infection has been demonstrated. To investigate the effect of CMV infection on the development of experimental chronic kidney allograft rejection, heterotopic kidney allografts from DA (Ag-B4, RT1a1) rat donors to WF (Ag-B2, RT1u) rat recipients were used. The animals received cyclosporine A (CsA) 5 mg/kg/day s.c. either for 1 or 12 weeks. Two groups of recipients were infected with 10(5) plaque-forming units of rat CMV (RCMV) and two other groups were left noninfected and used as controls. The grafts were removed 12 weeks after transplantation for histology and immunohistochemistry. RCMV infection significantly enhanced the development of chronic kidney allograft rejection in rats on continuous CsA the intensity of interstitial inflammation (P < 0.025), particularly the degree of pyroninophilic cells in the inflammatory infiltrate (P < 0.025), the glomerular mesangial matrix increase (P < 0.05) and capillary basement membrane thickening (P < 0.01), the extent of endothelial cell swelling (P < 0.025) and intimal proliferation (P < 0.025) in the graft vasculature, and the extent of tubular epithelial atrophy (P < 0.025). Chronic allograft damage index (CADI) was significantly increased to 4.3 +/- 0.8 in RCMV-infected allografts, compared to 0.8 +/- 0.4 in noninfected (P < 0.02). In addition, RCMV infection significantly increased the number of acute rejection episodes (serum creatinine > 200 mumol/liter, P < 0.05) and almost doubled the end-stage serum creatinine. RCMV infection significantly increased ICAM-1 expression on the vascular endothelium (P < 0.05) and tubular epithelial cells (P < 0.01), and was linked with enhanced interstitial, glomerular, and tubular inflammation. In 80% of allografts on continuous CsA, RCMV antigens could be observed in sporadic inflammatory cells one week after infection and in tubular epithelial cells at 12 weeks. In heavily inflamed allografts where the CsA treatment was discontinued at one week, enhancement of RCMV infection on the histological changes attributable to chronic kidney allograft rejection could not be demonstrated. Our results show that during CsA immunosuppression, RCMV infection enhances chronic kidney allograft rejection associated with increased interstitial inflammation as well as vascular endothelial and tubular epithelial ICAM-1 expression.

Animals↗
PubMed1995

Evolution of glomerular basement membrane changes in chronic rejection.

We have investigated the evolution of chronic glomerular changes in the absence of the recurrence of original disease in an experimental rat model of chronic renal allograft rejection. Using serial graft needle biopsies and serum creatinine levels, we were able to focus on early glomerular changes that are associated with good graft function. The recipient rats were divided into 5 groups, 2 with allogeneic (DA to WF) transplants and 3 with syngeneic (DA to DA) transplants. In the first 2 allogeneic groups, one group received cyclosporine (CsA) for 2 weeks (n = 7) and the other received CsA for 12 weeks (n = 5). In the 2-week treatment group, all allografts developed chronic rejection, compared with none in the 12-week group. Syngeneic controls received CsA for 2 (n = 3) and 12 weeks (n = 3), or no immunosuppression (n = 2) in order to exclude the effects of CsA. The first detectable ultrastructural event was slight deposition of electron lucent material in the glomerular basement membrane. Contrary to previous morphological studies, the initial deposition was not subendothelial, but was within the lamina densa itself. Examination of allogeneic grafts with good graft function and syngeneic grafts showed glomerular alterations that were similar to the early changes preceding chronic rejection. The intensity of changes in optimally immunosuppressed allografts was mild, and they were arrested early in the evolving stage of glomerular basement membrane changes. In the suboptimally immunosuppressed allografts with chronic rejection, the glomerular basement membrane changes became more pronounced and extensive in subsequent biopsies. Thus, all recipients in different groups showed similar glomerular alterations, but to different intensities. These results suggest a common pathogenetic mechanism which might be endothelial damage. In chronic rejection, the endothelial damage might be immunologically mediated by rejection episodes and progressive, whereas in syngeneic grafts and in allografts without chronic rejection, perioperative trauma, ischemia, and graft reperfusion may be responsible for the self-limiting glomerular changes.

Animals↗
PubMed1995

Urinary excretion of bufotenin (N,N-dimethyl-5-hydroxytryptamine) is increased in suspicious violent offenders: a confirmatory study.

We previously reported that violent offenders with paranoid symptoms or whose violent actions had been directed against family members had higher urinary levels of bufotenin than other violent offenders. In the present study, patients were evaluated with the Karolinska Scales of Personality (KSP), and urinary levels of bufotenin were determined by mass spectrometry. In drug-free patients suspiciousness was positively correlated, and socialization was negatively correlated, with urinary bufotenin excretion. These two personality variables were strongly interdependent. In drug users, bufotenin excretion was correlated positively with social desirability and negatively with irritability, but not with suspiciousness. Bufotenin excretion was not found to be associated with violence toward family members in the present study. The results are in keeping with the earlier finding that violent offenders with paranoid personality traits have higher urinary levels of bufotenin than other violent offenders.

Adult↗
PubMed1995

Mycophenolate mofetil (MMF, RS-61443) inhibits inflammation and smooth muscle cell proliferation in rat aortic allografts.

To investigate the impact of mycophenolate mofetil (MMF) on allograft arteriosclerosis (chronic rejection) in rat aortic allograft model, we administrated MMF 20 mg/kg/day from the day of transplantation and sacrificed the rats at 1-12 months afterwards. MMF significantly suppressed all major histological manifestations of allograft arteriosclerosis, i.e. adventitial inflammation, media necrosis and intimal thickening and cellularity. There was a significant decrease in the replication rate (3H-thymidine incorporation) of inflammatory cells in the adventitia and of smooth muscle cells (SMC) in the media. MMF did not have any major effect on mRNA expression of several growth factors, (determined by polymerase chain reaction with inbuilt glyceraldehyde-3-phosphate dehydrogenase control), which have previously been demonstrated to be elevated in nonimmunosuppressed allografts. Immunoperoxidase staining showed a 40% reduction in the number of adventitial interleukin-2 receptors expressing lymphoid cells in MMF-treated allografts. The intensity of SMC alpha-actin staining was also significantly reduced. As the results suggested that MMF may have a direct antiproliferative effect on SMC, this possibility was investigated in primary SMC cultures in vitro and using the carotid denudation model in vivo. Both approaches showed inhibition of SMC proliferation by MMF. Our results indicate that MMF inhibits histopathological changes of chronic rejection by reducing the immune response and possible replication of SMC.

Animals↗
PubMed1994

Personality profiles and state aggressiveness in Finnish alcoholic, violent offenders, fire setters, and healthy volunteers.

BACKGROUND: Based on clinical observations in a series of studies on Finnish alcoholic, violent offenders, we asserted that the impulsive offenders represented an extreme group of type 2 alcoholics. We also observed that these subjects were vulnerable to hypoglycemia after the administration of oral glucose load. Furthermore, we believe that while being hypoglycemic, the impulsive offenders are particularly irritable and aggressive. In the present study, we addressed these issues by studying psychological trait and state variables in a new group of violent offenders and fire setters, and age- and sex-matched healthy volunteers. METHODS: Fifty-eight alcoholic, violent offenders and impulsive fire setters and 21 healthy volunteers were administered the Karolinska scales of personality and the Rosenzweig picture frustration test after an oral aspartame and glucose challenge. RESULTS: The psychological test results and the criminal histories of the offenders, together with biochemical measurements, suggest that a low 5-hydroxyindoleacetic acid concentration in cerebrospinal fluid in the alcoholic offenders is associated with irritability and impaired impulse control, and a high free testosterone concentration in cerebrospinal fluid is associated with increased aggressiveness, monotony avoidance, sensation seeking, suspiciousness, and reduced socialization. CONCLUSION: Finnish alcoholic, impulsive offenders have personality profiles characteristic of Scandinavian early-onset male alcoholics with antisocial traits, who have been also referred to as type 2 alcoholics.

Adult↗