The combination of nanofibrous and microfibrous materials for enhancement of cell infiltration and in vivo bone tissue formation.

Fibrous scaffolds are desired in tissue engineering applications for their ability to mimic extracellular matrix. In this study we compared fibrous scaffolds prepared from polycaprolactone using three different fabrication methods, electrospinning (ES), electro-blowing and melt-blown combined with ES. Scaffolds differed in morphology, fiber diameters and pore sizes. Mesenchymal stem cell adhesion, proliferation and osteogenic differentiation on scaffolds was evaluated. The most promising scaffold was shown to be melt-blown in combination with ES which combined properties of both technologies. Microfibers enabled good cell infiltration and nanofibers enhanced cell adhesion. This scaffold was used for further testing in critical sized defects in rabbits. New bone tissue formation occurred from the side of the treated defects, compared to a control group where only fat tissue was present. Polycaprolactone fibrous scaffold prepared using a combination of melt-blown and ES technology seems to be promising for bone regeneration. The practical application of results is connected with enormous production capacity and low cost of materials produced by melt-blown technology, compared to other bone scaffold fabrication methods.

Chlorisondamine, a sympathetic ganglionic blocker, moderates the effects of whole-body irradiation (WBI) on early host defense to a live bacterial challenge.

There is a growing consensus that long-term deficits in the brain are due to dynamic interactions between multiple neural and immune cell types. Specifically, radiation induces an inflammatory response, including changes in neuromodulatory pro- and anti-inflammatory cytokine secretion. The purpose of this study was to establish that there is sympathetic involvement in radiation-induced decrements early in in vivo immune function host defense. Female, 8-9 week-old C57BL/6J mice were exposed to whole-body irradiation (WBI). There were 8 groups with radiation (0 vs. 3 Gy protons), immune challenge (Escherichia coli) and exposure to the sympathetic ganglionic blocker, chlorisondamine (1 mg/kg weight, i.p.), as independent variables. Ten days post-irradiation, mice were inoculated with E. coli intraperitoneally and sacrificed 90-120 min later. The data suggest that radiation-induced changes in immune function may in part be mediated by the sympathetic nervous system. Briefly, we found that radiation augments the bacteria-induced inflammatory cytokine response, particularly those cytokines involved in innate immunity. However, this augmentation can be reduced by the ganglionic blockade.

Low-dose photons modify liver response to simulated solar particle event protons.

The health consequences of exposure to low-dose radiation combined with a solar particle event during space travel remain unresolved. The goal of this study was to determine whether protracted radiation exposure alters gene expression and oxidative burst capacity in the liver, an organ vital in many biological processes. C57BL/6 mice were whole-body irradiated with 2 Gy simulated solar particle event (SPE) protons over 36 h, both with and without pre-exposure to low-dose/low-dose-rate photons ((57)Co, 0.049 Gy total at 0.024 cGy/h). Livers were excised immediately after irradiation (day 0) or on day 21 thereafter for analysis of 84 oxidative stress-related genes using RT-PCR; genes up or down-regulated by more than twofold were noted. On day 0, genes with increased expression were: photons, none; simulated SPE, Id1; photons + simulated SPE, Bax, Id1, Snrp70. Down-regulated genes at this same time were: photons, Igfbp1; simulated SPE, Arnt2, Igfbp1, Il6, Lct, Mybl2, Ptx3. By day 21, a much greater effect was noted than on day 0. Exposure to photons + simulated SPE up-regulated completely different genes than those up-regulated after either photons or the simulated SPE alone (photons, Cstb; simulated SPE, Dctn2, Khsrp, Man2b1, Snrp70; photons + simulated SPE, Casp1, Col1a1, Hspcb, Il6st, Rpl28, Spnb2). There were many down-regulated genes in all irradiated groups on day 21 (photons, 13; simulated SPE, 16; photons + simulated SPE, 16), with very little overlap among groups. Oxygen radical production by liver phagocytes was significantly enhanced by photons on day 21. The results demonstrate that whole-body irradiation with low-dose-rate photons, as well as time after exposure, had a great impact on liver response to a simulated solar particle event.

[C-reactive protein in diagnosis of complications in renal insufficiency and failure]. / C-reaktivní protein v diagnostice komplikací pri ledvinové nedostatecnosti a selhání.

C-reactive protein (CRP) is one of the positive proteins in an acute phase. It is produced in hepatocytes in response to cytokines activity, especially to IL-6. Its increase is the second biggest after significant bacterial and cardiovascular insults. It reaches its peak between 24 and 48 hours. CRP monitoring makes possible monitoring of the intensity of the pathologic process and to control efficiency of treatment measures according to fluctuation of its level. According to its serum values it can reflect a place of inflammation, e.g. in upper or lower airways, urinary tract etc. It helps to distinguish between bacterial and viral inflammations and to identify size of vascular lesions such as acute myocardial infarction, cerebral infarction, decompensation of atherosclerosis. Because of its easy detection and quick elevation CRP has not only a diagnostic importance but also a prognostic one and is a predictor of a risk of atherosclerosis. Although long lasting renal insufficiency (LLRI), renal failure (RF) and regular dialysis treatment (RDT) are indicated to elevate CRP level, authors present proves that adequately treated patient compensated with an adequate dialysis treatment has normal CRP values for a long time in spite of long lasting comorbidities including atherosclerosis. There has been done a long term monitoring of 10 patients with LLRI and 22 patients with RDT. Their CRP was monitored via a turbidimetric method using sets K-Assay made by company Kamya Bio Comp. Elevated CRP in the samples reflects an acute insult such as infection, cardiovascular disease, diabetes decompensation and last but not least quality of a dialysis treatment.

[Ambulatory monitoring of blood pressure in regular dialysis therapy]. / Ambulantní monitorování krevního tlaku v pravidelném dialyzacním lécení.

Ambulatory monitoring of the blood pressure (AMBP) makes it possible to diagnose in hypertensive patients the so-called dipper phenomenon, i.e. a drop of the BP during the night provided that the patient is asleep. The absence of this phenomenon implies as a rule serious damage of the cardiovascular apparatus, brain or kidneys. By means of an apparatus ABP monitoring type 90207 of Space Labs. Inc. a group of 16 patients in regular dialysis treatment (RDT) was examined and the blood pressures were evaluated before and after dialysis. Patients with the dipper profile reacted more adequately during dialysis i.e. by a drop of the blood pressure due to the loss of excessive fluid which they retained during the interdialysis period, as compared with the group with a non-dipper profile which may be exposed to a greater risk of cardiovascular complications. The authors conclude that detection of the absence of the non-dipper phenomenon can reveal risk patients. AMBP can explain so-called paradoxical hypertension at the end of haemodialysis despite major removal of fluids by ultrafiltration, and that moxonidine participates in a significant way in the elimination of the non-dipper phenomenon.

Radiation enhances the anti-tumor effects of vaccinia-p53 gene therapy in glioma.

The overall goal of this study was to analyze the effect and mechanism of radiation in combination with vaccinia viruses (VV) carrying the p53 gene against glioma. Comparison of two alternative treatments of cultured C6 (p53(+)) and 9L (p53(-)) rat glioma cells showed significantly reduced survival for both cell lines, especially 9L, when radiation was applied prior to virus versus radiation alone. High p53 protein expression mediated by VV-TK-p53 was measured in infected cells. Single modality treatment of C6 cells with psoralen and UV (PUV)-inactivated VV-TK-p53 (PUV-VV-TK-53) or radiation significantly decreased survival compared with PUV-inactivated L-15 (PUV-L-15) control virus. However, no difference was observed between radiation and combination treatments of C6 cells. In contrast, radiation followed by PUV-VV-TK-53 resulted in dramatic reduction of 9L cell viability, compared to single modality treatment. Flow cytometry analysis of Annexin-V-stained 9L cells showed that radiation and PUV-VV-TK-53 caused a significant decrease in live cells (17.2%) as compared to other treatments and control (61.6-98.3%). Apoptosis was observed in 37.2% of cells, while the range was 0.7-7.8% in other treatment groups; maximal p53 level was measured on day 7 post-infection. In athymic mice bearing C6 tumors, VV-TK-53 plus radiation in both single and multiple therapies resulted in significantly smaller tumors by day 30 compared to the agents given only once. Immunohistochemical analysis of tumor sections demonstrated p53 protein expression over 20 days after VV-TK-53 treatment. Analysis of blood and spleen cells of mice given multiple combination treatments showed significant splenomegaly, leukocytosis, and increased DNA synthesis and response to mitogen. Multiple combination treatments were also associated with significantly elevated natural killer and B cells in the spleen. There were no overt toxicities, although depression in red blood cell and thrombocyte parameters was noted. Collectively, the data demonstrate that radiation significantly improves the efficacy of VV-mediated tumor suppressor p53 therapy and may be a promising strategy for glioma treatment. Furthermore, the results support the conclusion that the mechanisms underlying the enhanced anti-tumor effect of combination treatment include apoptosis/necrosis and upregulation of innate immune defenses.

Evaluation of TNF-alpha/Bax gene therapy and radiation against C6 glioma xenografts.

Successful therapy of high-grade tumors of the brain is likely to require a combination of new therapeutic approaches. The major goal of the present study was to construct a plasmid-based bax gene vector (pGL1-Bax) and evaluate its expression in vitro and in vivo using athymic mice with subcutaneously growing C6 glioma. Preliminary experiments of efficacy and safety were also performed using pGL1-Bax alone and in combination with previously constructed pGL1-TNF-alpha, as well as with radiation. pGL1-Bax was expressed by C6 cells and was correlated with apoptosis, indicating that the construct and the bax protein were functional. Although intratumoral injections of pGL1-Bax alone, up to total doses of 450 micro g, did not significantly affect tumor growth, consistently smaller tumors were obtained when pGL1-TNF-alpha plus pGL1-Bax were injected 16-18 hr prior to tumor irradiation. Furthermore, in mice with two tumors, one treated and one untreated, progression of the untreated tumor was delayed in the animals receiving all three modalities. No prohibitive toxicities were noted, based on mouse body weights and in vitro assays of blood and spleen. Significant increases in spleen mass, total leukocyte counts, percentage of granulocytes, spontaneous blastogenesis, and CD71-expressing B cells were primarily associated with tumor presence and not treatment type. Overall, the results are promising and suggest that TNF-alpha/Bax gene therapy may be beneficial against highly malignant tumors of the brain. To our knowledge, this is the first report of bax gene therapy used together with radiation in an in vivo glioma model.

[Transjugular intrahepatic portosystemic shunt (TIPS) in the treatment of symptomatic portal hypertension]. / Transjugulární intrahepatální portosystémový zkrat (TIPS) pri lécbe symptomatické portálni hypertenze.

BACKGROUND: A transjugular intrahepatic portosystemic shunt (TIPS) is the creation of a percutaneous portosystemic anastomosis which is used as an alternative method of surgical portosystemic shunts and endoscopic treatment in the therapy of complications of portal hypertension. The objective of the present work was to summarize experience with TIPS in 100 patients. METHODS AND RESULTS: In 1992-1995 the authors treated 100 patients with symptomatic portal hypertension by TIPS. To create the shunt in 84% patients a spiral Z stent was used, in the remainder a Wallstent. In 86% patients the indication for TIPS was haemorrhage associated with portal hypertension and in 14% refractory ascites. TIPS was implemented in 98% patients. The pressure in the portal vela was not reduced on average to 58% of the original value. Haemorrhage was not stopped in one of 7 patients. Haemorrhage from varices reappeared in 7% patients indicated on account of repeated haemorrhage and was always associated with the finding of chronic stenosis of the shunt. The mortality in conjunction with the procedure was 4%, the mortality within 30 days after operation was 8%. Uncontrollable encephalopathy developed in 3% of the patients. Primary patency of the shunt created by the spiral Z stent was 85% after 6 months, after 12 months 72% and thus does not differ from primary patency when Wallstents are used, as reported in the literature. CONCLUSIONS: TIPS is an effective method to reduce the pressure in the portal vein in portal hypertension. The main limiting factor of the method is stenosis of the shunt due to hyperplasia of the neointima. Stenoses of the shunt can be effectively dilated by percutaneous balloon angioplasty.

Kinetics of phenols in body fluid compartments during hemodialysis.

On the basis of direct quantification of hemodialysis (HD), the kinetics of phenols (Ph) were followed in 13 patients on regular HD treatment. The average plasma levels of Ph before and after HD were 627 +/- 109 mumol/L and 416 +/- 81 mumol/L, respectively. The total amount of Ph removed during 5-h HD was 7,481 +/- 1,894 mumol. For calculation of the generation rate (G), a new formula has been derived not requiring knowledge of the corresponding volume of distribution. The G of Ph was 2.9 +/- 0.7 mumol/min on average. The mean dialysis clearance (K) of Ph was 48.2 +/- 10.2 ml/min.

[Changes in amino acids in a regular dialysis program]. / Aktuální zmeny aminokyselin v pravidelném dialyzacním programu.

BACKGROUND: Dialyzed patients are chronically in a state of negative nitrogen balance, and amino acids, their building stones, are also significantly affected by dialysis. The purpose of the present investigation was to assess whether they should be supplied, how frequently and for how long and how they are influenced by the usual diet of patients. METHODS AND RESULTS: The examination was made in a group of 13 patients included in a regular haemodialysis programme. Their mean age was 53.2 +/- 12.4 years, they were dialyzed for an average period of 55 months, maximum 163 months. The patients were dialyzed three times per week for four hours, bicarbonate dialysate was used. The patients' diet was not modified in any way. A total of 52 haemodialysis were examined: losses of alpha-amino nitrogen were monitored as well as changes of serum concentrations of different amino acids. Their mean losses were 119 +/- 54.69 mmol/4 h: this corresponds to 10.5 +/- 4.8 mg amino acids. The dialysis clearance was on average 122.7 +/- 63.2 ml/min. This value did not differ significantly from the dialysis clearance of urea, but it was significantly higher than creatinine clearance (p < 0.05). During dialysis a significant drop (p < 0.001) of the plasma concentration of amino nitrogen occurred, however, the changes of serum concentrations of amino acids differed. A significant drop was recorded in serum concentrations of histamine, lysine, cysteine, methionine, tyrosine, glycine, asparagine, citrullin, glutamine, taurine. Before the beginning of dialysis the values of valine, lysine, threonine, serine, alanine and asparagine were lower than corresponds to the reference interval in healthy subjects. CONCLUSIONS: Changes of serum concentrations of individual amino acids are significantly influenced not only by their losses into the dialysate but also by their shift from cells into the extracellular fluid and by resorption from the digestive tract during protein intake in the course of dialysis. An adequate supply of high quality protein can compensate for these losses. Investigation of serum concentration of individual amino acids does not record their kinetic changes but can give an idea on the effectiveness of the dietary regime.

[Determination of urea distribution space on the basis of hemodialysis quantification]. / Stanovení distribucního prostoru mocoviny na podklade kvantifikace hemodialýzy.

By using direct dialysis quantification--DDQ--in 124 haemodialyses made in 14 patients the authors assessed the urea output in mmol in the dialyzation fluid collected after every dialysis. The evaluation of total body fluids, which accounts roughly for 60% of the total body weight, was replaced by a calculated distribution space of urea (Vu) according to the Du/Ppre--Ppost formula. This equation was modified with regard to the degree of ultrafiltration and urea formation. The authors found a 5% difference between the values of the modified Vu equation and total body fluids corresponding to 60% of the body weight.

Effect of a hepatitis B vaccination program on the prevalence of hepatitis B virus infection.

In April 1991, surveys for serologic evidence of hepatitis B virus (HBV) infection were conducted among 3- to 4-year-old children born after a hepatitis B immunization program of newborns began and among 6- to 11-year-old children targeted for early childhood vaccination in American Samoa. Compared with 3- to 4-year-olds tested in 1991, children tested at baseline in 1985 were more likely to have been infected with HBV (5/40 vs. 2/93; prevalence ratio [PR] = 5.8, 95% confidence limits [CL] = 1.2, 28.7) and to have chronic infection with HBV (3/40 vs. 0/95; PR = undefined, lower CL = 1.2). Compared with 6- to 11-year-olds tested in 1991, children in 1985 were more likely to have been infected with HBV (32/121 vs. 53/386; PR = 1.9, CL = 1.3, 2.8) and to have chronic infection with HBV (8/121 vs. 7/386; PR = 3.6, CL = 1.3, 9.8). The incorporation of hepatitis B vaccine into routine childhood vaccination schedules can prevent acute and chronic HBV infection in areas of high endemicity.

[Determination of lactoferrin in the diagnosis of pancreatopathy in patients with chronic kidney failure]. / Stanovení laktoferinu v diagnostice pankreatopatií u nemocných s chronickým selháním ledvin.

The authors investigated in patients with renal disease the lactoferrin content in duodenal aspirate. The aspirate was obtained after previous stimulation of the pancreas with pancreozymin. Lactoferrin estimation is described in the literature as a sensitive examination of changes of exocrine pancreatic secretion. The authors provided evidence that by assessing lactoferrin it is possible to detect initial changes of reduced exocrine pancreatic capacity already in subjects who are on the waiting list of chronic intermittent haemodialyzation programmes (CHIDP); maximum increase of the lactoferrin content in the duodenal aspirate corresponds with the severity of chronic renal failure. Transplantation of the kidneys leads to normalization of the amount of lactoferrin secreted by the pancreas which is evidence of normalization of pancreatic secretion. In patients with chronic renal failure lactoferrin is a sensitive marker of developing uraemic pancreatopathy.

[Hemorrhage into the digestive tract as a cause of death in patients after kidney transplantation]. / Krvácení do zazívacího traktu jako prícina úmrtí u nemocných po transplantaci ledvin.

The authors investigated the prevalence, cause and possible prevention of haemorrhage into the gastrointestinal tract in 218 patients after transplantation of the kidney (TK). 1. Haemorrhage into the gastrointestinal tract after TK occurred in 32 patients incl. 53.1% who died. In the total mortality after TK haemorrhage into the gastrointestinal tract account for 15.7%. 2. The danger of haemorrhage into the gastrointestinal tract is increased in particular: in the early postoperative period (within one month after transplantation of the kidney), during acute rejection with declining function of the graft, in infectious complications, after graftectomy, in preexisting peptic ulcers. 3. The most frequent cause of haemorrhage were duodenal ulcers. The authors elaborated a system of preventive provisions which involve: a) medicamentous prophylaxis by administration of H2 blockers and antacids not only at the time of transplantation of the kidney and during the early postoperative period but also when there is an increased risk, b) detailed gastroenterological examination before transplantation of the kidney, c) in case of relapsing peptic ulceration in the case-history or haemorrhage into the gastrointestinal tract, subject patients on the waiting list for transplantation of the kidneys during the dialyzation period to proximal gastric vagotomy, or so-called highly selective vagotomy.

[The critical value of residual kidney function in patients with chronic kidney failure from the viewpoint of the concentration of urea and potassium in the plasma]. / Kriticheskaia velichina ostatochnoi funktsii pochek u bol'nykh s khronicheskoi pochechnoi nedostatochnost'iu s tochki zreniia kontsentratsii mocheviny i kaliia v plazme.

Residual kidney function was examined in 10 patients with chronic renal insufficiency under balance conditions and in 30 outpatients on the basis of urea clearance (Curea) and potassium clearance (CK). Protein intake was 35-40 g/day (0.5 g/kg/day) and potassium intake was 30-40 mmol/day. Under these conditions the critical values of residual kidney function were as follows: 1) plasma urea concentration (Purea) did not exceed 30 mmol/l if Curea did not drop below 3.8 ml/min; 2) plasma potassium concentration (PK) did not exceed 5 mmol/l if CK did not decrease below 4.1 ml/min. Clinical examination of Curea and CK provides additional information to the examination of creatinine clearance (Ccr) or its plasma concentration (Pcr). Our results suggest that the critical value of residual kidney function cannot be defined only on the basis of examination of Ccr or Pcr. Examination of Curea and CK can help in the interpretation of very high Purea and hyperkalemia in patients with chronic renal insufficiency.

[Visual function in patients with neuroretinopathy on regular dialysis treatment]. / Zrakové funkce u nemocných v pravidelné dialyzacní lécbe po neuroretinopatii.

Eight patients included in a regular dialyzation programme who developed neuroretinopathy were subjected to improved dialyzation treatment. It involved variation of sodium and variation of ultrafiltration. After regression of acute symptoms on the fundus in all patients a vision of 6/6 was achieved. Patients with neuroretinopathy have a markedly reduced contrast sensitivity. The latter increases considerably after absorption of the oedema, although it does not attain values recorded in healthy subjects.

[The critical level of renal function in patients with chronic renal failure from the aspect of maintaining normal levels of potassium in the blood]. / Kritická hodnota cinnosti ledvin u nemocných s chronickým ledvinovým selháním z hlediska udrzování normální plazmatické koncentrace draslíku.

In 29 subjects with chronic renal failure (Pkr = 826 +/- 69 mumol/, Ckr 0.128 +/- +0.039 ml/s) treated by conservative therapy the urinary excretion and residual renal potassium clearance (CK) was investigated. In 17% of these patients the plasma potassium level (PK) was higher than 5 mmol/l. The PK levels were not significantly related to the value of the residual diuresis, to the daily urinary potassium excretion nor the value of residual creatinine clearance. A significant relationship was found between values PK and CK. The critical CK value where PK rises above 5 mmol/l (under conditions of reduced protein intake 0.5 g/kd/day and a potassium intake not exceeding 40 mmol/l/24 hours) suggests the participation of extrarenal factors (excessive K intake or it's increased shift from cells to extracellular fluid).

Occurrence of neuroretinopathy in dialyzed patients.

In the last 11 years, the neuroretinopathy is reported to occur in 26 dialyzed patients, what represents 5.3% of all patients treated. During the last 4 years, the occurrence rate showed the decrease to 1.6%. The mentioned disease occurs most frequently by the first two years of treatment with dialysis. The averaged survival rate after the onset of neuroretinopathy is ranged as 19.4 mos. in 16 died patients. The disease occurred in 13 patients under the condition of normal diastolic pressure. Metabolic disorder characterized with high levels of serum nitrogenic substances may be further factor inducing the onset of neuroretinopathy backgrounded by cerebral oedema. Since neuroretinopathy consequentially worsens both the subjective (visual acuity, sensitivity to the contrast) and objective (electric activity) sight functions, the appropriate attempt is to be made in achieving rapidly retrogression of pathologic retinal changes by modification of dialysis process.

Residual kidney function and plasma urea concentration in patients with chronic renal failure.

The relationships between the plasma levels of urea (P(urea)), renal clearance of urea (C(urea)) and creatinine (Ccr) at an intake of 0.5 g protein/kg body weight/day were followed in 10 patients with chronic renal failure (CRF) under balance conditions. Under these conditions, P(urea) attained a value of 30 mmol/l when C(urea) had decreased below 3.8 ml/min. By contrast, no correlation could be demonstrated between P(urea) and Ccr under these conditions. The same relationships were followed in another group of 30 outpatients with CRF. Even in patients not followed under balance conditions, C(urea) determination makes it possible to establish whether the high increase in P(urea) is due to the decrease in residual renal function below the critical level or whether extrarenal factors are involved. Likewise, no significant correlation between P(urea) and Ccr could be demonstrated under these conditions. The findings suggest that C(urea) measurement in CRF patients helps to assess residual renal function in terms of P(urea) regulation and provides information that cannot be obtained by Ccr measurement.