Islet Transplantation - perspective from Poland

The article describes impact of advanced research in the USA and collaborative approach of US scientists and clinicians on development of the field of islet transplantation in Poland and all over the world. At the same time, it presents negative consequences of islet regulation by FDA as a biological drug leading to decline and extinction of the field in the US, while it is on the rise worldwide.

Template-to-distractor distinctiveness regulates visual search efficiency

All models of attention include the concept of an attentional template (or a target or search template). The template is conceptualized as target information held in memory that is used for prioritizing sensory processing and determining if an object matches the target. It is frequently assumed that the template contains a veridical copy of the target. However, we review recent evidence showing that the template encodes a version of the target that is adapted to the current context (e.g. distractors, task, etc.); information held within the template may include only a subset of target features, real world knowledge, pre-existing perceptual biases, or even be a distorted version of the veridical target. We argue that the template contents are customized in order to maximize the ability to prioritize information that distinguishes targets from distractors. We refer to this as template-to-distractor distinctiveness and hypothesize that it contributes to visual search efficiency by exaggerating target-to-distractor dissimilarity.

Learned feature variance is encoded in the target template and drives visual search

Real world visual search targets are frequently imperfect perceptual matches to our internal target templates. For example, the same friend on different occasions is likely to wear different clothes, hairstyles, and accessories, but some of these may be more likely to vary than others. The ability to deal with template-to-target variability is important to visual search in natural environments, but we know relatively little about how feature variability is handled by the attentional system. In these studies, we test the hypothesis that top-down attentional biases are sensitive to the variance of target feature dimensions over time and prioritize information from less-variable dimensions. On each trial, subjects were shown a target cue composed of colored dots moving in a specific direction followed by a working memory probe (30%) or visual search display (70%). Critically, the target features in the visual search display differed from the cue, with one feature drawn from a distribution narrowly centered over the cued feature (low-variance dimension), and the other sampled from a broader distribution (high-variance dimension). The results demonstrate that subjects used knowledge of the likely cue-to-target variance to set template precision and bias attentional selection. Moreover, an individual's working memory precision for each feature predicted search performance. Our results suggest that observers are sensitive to the variance of feature dimensions within a target and use this information to weight mechanisms of attentional selection.

External Validation of the Newly Developed BETA-2 Scoring System for Pancreatic Islet Graft Function Assessment

BACKGROUND

BETA-2 score using a single fasting blood sample was developed to estimate beta-cell function after islet transplantation (ITx) and was validated internally by a high ITx volume center (Edmonton). The goal was to validate BETA-2 externally, in our center.

METHODS

Areas under receiver operating characteristic curves (AUROCs) were obtained to see if beta score or BETA-2 would better detect insulin independence and glucose intolerance.

RESULTS

We analyzed values from 48 mixed meal tolerance tests (MMTTs) in 4 ITx recipients with a long-term follow-up to 140 months (LT group) and from 54 MMTTs in 13 short-term group patients (ST group). AUROC for no need for insulin support was 0.776 (95% confidence interval [CI] 0.539-1, P = .02) and 0.922 (95% CI 0.848-0.996, P < .001) for beta score and 0.79 (95% CI 0.596-0.983, P = .003) and 0.941 (95% CI 0.86-1, P < .001) for BETA-2, in LT and ST groups, respectively, and did not differ significantly. In LT group BETA-2 score ≥ 13.03 predicted no need for insulin supplementation with sensitivity of 98%, specificity of 50%, positive predictive value (PPV) of 93%, and negative predictive value (NPV) of 75%. In ST group the optimal cutoff was ≥13.63 with sensitivity of 92% and specificity, PPV, and NPV 82% to 95%. For the detection of glucose intolerance BETA-2 cutoffs were <19.43 in LT group and <17.23 in ST group with sensitivity > 76% and specificity, PPV, and NPV > 80% in both groups.

CONCLUSION

BETA-2 score was successfully validated externally and is a practical tool allowing for frequent and reliable assessments of islet graft function based on a single fasting blood sample.

Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph

Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the [Formula: see text] configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the [Formula: see text] matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of [Formula: see text]0.170 ns for 15 cm axial field-of-view (AFOV) and [Formula: see text]0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.

Donor height in combination with islet donor score improves pancreas donor selection for pancreatic islet isolation and transplantation

To maximize the islet isolation yield for successful islet transplantation, the key task has been to identify an ideal pancreas donor. Since implementation of the islet donor score in donor selection, we have consistently obtained higher islet yields and transplantation rates. In this study, we tested whether assessing donor height as an independent variable in combination with the donor score could improve the pancreas donor selection. Donor and islet isolation information (n = 22) were collected and studied between 2011 and 2012. Pearson correlation analysis was used in statistical analysis. Donor height as an independent variable was significantly correlated to the weight of the pancreas, pre-Islet Equivalents (pre-IEQ), post-IEQ, and IDS (P < .05). When donor with height of 179 cm ± 3 was selected in combination with IDS > 80, the clinical islet transplantation rate reached 80%.

Improved coating of pancreatic islets with regulatory T cells to create local immunosuppression by using the biotin-polyethylene glycol-succinimidyl valeric acid ester molecule

BACKGROUND

We showed that T regulatory (Treg) cells can be attached to the surface of pancreatic islets providing local immunoprotection. Further optimization of the method can improve coating efficiency, which may prolong graft survival. In this study, we compared the effectiveness of two different molecules used for binding of the Tregs to the surface of pancreatic islets. Our aim was to increase the number of Treg cells attached to islets without compromising islets viability and function.

METHODS

The cell surface of human Treg cells and pancreatic islets was modified using biotin-polyethylene glycol-N-hydroxylsuccinimide (biotin-PEG-NHS) or biotin-PEG-succinimidyl valeric acid ester (biotin-PEG-SVA). Then, islets were incubated with streptavidin as islet/Treg cells binding molecule. Treg cells were stained with CellTracker CM-DiL dye and visualized using a Laser Scanning Confocal Microscope. The number of Treg cells attached per islets surface area was analyzed by Imaris software. The effect of coating on islet functionality was determined using the glucose-stimulated insulin response (GSIR) assay.

RESULTS

The coating procedure with biotin-PEG-SVA allowed for attaching 40% more Treg cells per 1 μm(2) of islet surface. Although viability was comparable, function of the islets after coating using the biotin-PEG-SVA molecule was better preserved than with NHS molecule. GSIR was 62% higher for islets coated with biotin-PEG-SVA compared to biotin-PEG-NHS.

CONCLUSION

Coating of islets with Treg cells using biotin-PEG-SVA improves effectiveness with better preservation of the islet function. Improvement of the method of coating pancreatic islets with Treg cells could further facilitate the effectiveness of this novel immunoprotective approach and translation into clinical settings.

Islet product characteristics and factors related to successful human islet transplantation from the Collaborative Islet Transplant Registry (CITR) 1999-2010

The Collaborative Islet Transplant Registry (CITR) collects data on clinical islet isolations and transplants. This retrospective report analyzed 1017 islet isolation procedures performed for 537 recipients of allogeneic clinical islet transplantation in 1999-2010. This study describes changes in donor and islet isolation variables by era and factors associated with quantity and quality of final islet products. Donor body weight and BMI increased significantly over the period (p<0.001). Islet yield measures have improved with time including islet equivalent (IEQ)/particle ratio and IEQs infused. The average dose of islets infused significantly increased in the era of 2007-2010 when compared to 1999-2002 (445.4±156.8 vs. 421.3±155.4×0(3) IEQ; p<0.05). Islet purity and total number of β cells significantly improved over the study period (p<0.01 and <0.05, respectively). Otherwise, the quality of clinical islets has remained consistently very high through this period, and differs substantially from nonclinical islets. In multivariate analysis of all recipient, donor and islet factors, and medical management factors, the only islet product characteristic that correlated with clinical outcomes was total IEQs infused. This analysis shows improvements in both quantity and some quality criteria of clinical islets produced over 1999-2010, and these parallel improvements in clinical outcomes over the same period.

When the living and the deceased cannot agree on organ donation: a survey of US organ procurement organizations (OPOs)

The legal concept of first person authorization (FPA) is based on the principle that a decision by a person with decision-making capacity should be respected even after he or she dies. Although the transplant community largely supports this concept, its implementation has not been universal. We conducted a web-based survey of all 58 Organ Procurement Organization (OPO)executive directors in the United States to assess OPOs' procurement policies and practices in the context of family objections. All 58 respondents(100%) responded to our survey. All OPOs except one have an online donor registration website. Most OPOs(89%) (51 of 57 respondents) estimated that the frequency of family objecting to organ donation in cases of registered donors was <10%. No OPOs reported the frequency to be higher than 25%. Only 50% (27 of 54) of the OPOs have a written policy on handling family objections. Approximately 80% of the OPOs reported honoring FPA. However, in the past 5 years, 20 OPOs (35%) have not yet participated in organ procurement from a registered deceased donor over family objection. Further research to identify the barriers and possible solutions to implementing FPA is warranted.

Are mesh anchoring sutures necessary in ventral hernioplasty? Multicenter study

BACKGROUND

Avoiding mesh fixation to the surrounding tissue in ventral hernioplasty would simplify the operation, decrease the time of the procedure, and decrease the risk of suture-related complications.

METHODS

Four hospitals included 111 patients according to the common protocol for prospective clinical evaluation of sutureless ventral hernioplasty. Surgical technique involves placement of the polypropylene mesh with flat-shape memory in either the retromuscular or preperitoneal space without suture anchoring.

RESULTS

Local complication rate was low (12.6%, 14 patients), postoperative pain measured according to the visual analogue scale was minimal (mean 4, range 1-8). Three recurrences (3%) were recorded. Mild scar discomfort, which did not require treatment nor limit physical activity, was recorded in 28 (25%), 18 (17%), and 11 (14%) patients at 6-month, 1- and 2-year follow-up, respectively.

CONCLUSIONS

Results of the study suggest that the sutureless sublay technique is safe and effective in the treatment of ventral abdominal hernia, especially in small and medium defects.

Validation of the scoring system for standardization of the pancreatic donor for islet isolation as used in a new islet isolation center

BACKGROUND

The aim of this study was to evaluate the effectiveness of the Edmonton Donor Scoring System for use in our much less active islet center. Because the ability to recognize an appropriate donor may help to achieve consistent and predictable success of pancreatic islet isolation, it should lead to increased effectiveness and lower cost.

MATERIAL AND METHODS

Charts of 36 consecutive pancreas donors were reviewed to assess the donor points (DP). DP ranged from 0 to 100 based on donor age, body mass index, cause of death, social and medical history, hospital stay, vasopressor dosages, laboratory tests, cold ischemia time and procurement team, as well as pancreas size, consistency, fat content, damage, and quality of procurement and packing.

RESULTS

Successful isolation was achieved in 39% of donors (14 of 36), a value similar to that achieved in Edmonton (40%). We used the optimal cutoff value (DP = 79) proposed by the Edmonton group. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 66%, 75%, 57%, 82% and 72%, respectively. Successful islet isolation from poor or marginal donors (DP < 49.5 and 50 to 59.5) was 0% and 28.6% respectively; it was 63% and 100% in optimal donors (DP = 80 to 89.5 and 90 to 100). We concluded that islet isolation success correlated with the previously proposed donor scoring system.

CONCLUSIONS

The Donor Scoring System can be successfully implemented regardless of the level of activity of an experienced isolation center. This system permits identification of a suitable donor prior to organ processing. It may guide a center's donor selection strategy based on its goals and its budget.

Management of inguinal hernia on peritoneal dialysis: an audit of current Polish practice and call for a standard

Peritoneal dialysis is becoming more and more common as a method of treating patients at the final stage of renal failure. In the year 2002 the number of patients treated with this method in Poland amounted to 1324. Studies have demonstrated that inguinal and abdominal hernias develop more frequently in chronic renal failure patients. The percentage of patients with hernia diagnosed within the first five years of dialysis is about 10%. Continuation of dialysis with the hernia condition left untreated may result in severe complications which are the third most frequent cause of converting treatment method into hemodialysis in PD patients. Currently in Poland there is no national standard in existence as to the management of hernias, and the only British standard from 1998 does not reflect the present expertise of either surgical treatment or dialysis methods. The aim of the current questionnaire based study investigating Polish peritoneal dialysis centers was to assess the treatment when hernia had been diagnosed in the PD patient. Of 49 dialysis centers in Poland, 39 do have protocols on managing the patient before and after the operation. A considerable diversity has been found as to surgical techniques used and the ways the patients are managed in hospital. Following the need expressed by 33 dialysis centers in Poland for some standard for relevant procedures, the authors formulated principles of modern hernia treatment in PD patients. Accordingly, the main principles include: 1) consulting a surgeon collaborating with the center before qualifying for peritoneal dialysis and when hernia symptoms have manifested; 2) Tension-free methods used in a treatment of choice (recommended by PHS); 3) Application of antibiotic prophylaxis (preferably first generation cephalosporin); 4) Induction of local or epidural anesthesia; 5) Peritoneal dialysis programme does not need to be discontinued but low volume dwells or preferably intermittent APD is recommended immediately after surgery.

Is there a need for a mesh plug in inguinal hernia repair? Randomized, prospective study of the use of Hertra 1 mesh compared to PerFix Plug

Although the mesh plug procedure is an effective operation, sutureless implantation of a single onlay mesh, if successful, would avoid the risks of plug-related complications. One hundred patients with primary inguinal hernias were randomized to undergo PerFix Plug or Hertra 1 implantation. Mean duration of the operation was similar, 38 versus 35 min for plug and onlay mesh implantation, respectively (nonsignificant, NS). The level of postoperative pain and early complication rate was similarly low in both groups (NS). Recurrence rate was the same-2 patients in each group (4%)-all following large hernia repair. The level of long-term discomfort was low after each type of operation (NS). Implantation of the onlay mesh-Hertra 1 as compared to the use of PerFix Plug is simple, safe, and equally effective in small and medium inguinal hernia repair, suggesting that a plug device is not necessary for successful hernia surgery.

Myocardial homing and neovascularization by human bone marrow angioblasts is regulated by IL-8/Gro CXC chemokines

In the adult, new blood vessel formation can occur either through angiogenesis from pre-existing mature endothelium or vasculogenesis mediated by bone marrow-derived endothelial precursors. We recently isolated endothelial progenitor cells, or angioblasts, in human adult bone marrow which have selective migratory properties for ischemic tissues, including myocardium, to where they home and induce vasculogenesis. Here we show that myocardial production of the IL-8/Gro-alpha CXC chemokine family is significantly increased after acute ischemia, and that this provides a chemoattractant gradient for bone marrow-derived endothelial progenitors, or angioblasts. This chemokine-mediated homing of bone marrow angioblasts to the ischemic heart regulates their ability to induce myocardial neovascularization, protection against cardiomyocyte apoptosis, and functional cardiac recovery. Together, our results indicate that CXC chemokines play a central role in regulating vasculogenesis in the adult, and suggest that manipulation of interactions between chemokines and their receptors on autologous human bone marrow-derived angioblasts could augment neovascularization of ischemic myocardial tissue.

Effect of streptavidin on cardiac allograft prolongation is due to host T-Cell suppression

AIM

The aim of this study was to evaluate the effectiveness of streptavidin immunomodulation in the high-responder WF-to-Lewis combination.

METHODS/RESULTS

We examined the effects of streptavidin on the proliferative response of T cells in coculture studies. Two to 200 microg/mL streptavidin significantly (P < .001) suppressed the proliferation of Lewis T cells to WF by 76%-83% compared with untreated responders. Next, we studied the survival of WF cardiac allografts in Lewis recipients pretreated with streptavidin. A 5-day course of peritransplantation recipient treatment with streptavidin doses of 8, 12, 20, 40, and 60 mg/kg combined with single dose of 0.5 mL antilymphocyte serum (ALS) significantly (P < .001) prolonged cardiac allograft survival from MST of 7 +/- 0.5 and 8 +/- 0.5 days in naive and ALS-treated controls to 15 +/- 1, 20 +/- 3, 16 +/- 3, 17 +/- 3, and 23 +/- 2 days, respectively. In contrast, posttransplantation administration of 80 mg/kg streptavidin resulted in animal death, suggesting toxicity of this dose. Additionally, 10 mg/kg or 20 mg/kg streptavidin administration for 10 consecutive days resulted in significant graft prolongation (MST of 18 +/- 1 and 21 +/- 1 days, respectively; P < .001).

CONCLUSION

Although peritransplantation streptavidin treatment is effective in prolonging rat cardiac allografts in the high-responder WF-to-Lewis combination, it does not induce permanent graft survival as observed in the low-responder combination of Lewis-to-ACI. Our finding of in vitro immunomodulatory effect of streptavidin on T-cell proliferation suggests that its in vivo effect is partly due to prevention of T-cell activation following antigen exposure.

Two-Layer Method in Short-Term Pancreas Preservation for Successful Islet Isolation

BACKGROUND

We sought to determine whether the two-layer method (TLM) offers advantages over UW storage solution for locally procured pancreata with cold ischemia time of <8 hours for successful islet isolation.

METHODS

From October 2003 through February 2005, 22 human pancreata were procured locally from cadaveric donors and preserved using UW solution (n = 11) or TLM (n = 11).

RESULTS

Donor characteristics were similar in the two groups, with no statistical difference. Cold ischemia time was 4.5 +/- 0.6 (2.5 to 8) hours in the UW and 5.1 +/- 0.5 (3 to 8) hours in TLM group (P > .05). Organs preserved with TLM were exposed to PFC for 4 +/- 0.5 (2 to 7.5) hours. After TLM preservation, 8 of 11 (72%) pancreata yielded >300,000 IEQ pancreatic islets, which met all criteria for clinical transplantation; after UW cold storage, only 3 of 11 isolations were equally successful (27%) (P < .05). Mean IEQ was higher in the TLM than in the UW group: 349,000 +/- 37,000 vs 277,800 +/- 34,000; IEQ/g was also higher at 5100 +/- 760 vs 3000 +/- 570, respectively (P < .05). Islet quality, characterized by purity, viability, and insulin SI, did not differ statistically in the two groups: 67 +/- 4 vs 74 +/- 4%, 87 +/- 2 vs 83 +/- 4%, and 4 +/- 0.7 vs 4.8 +/- 1, respectively (P > .05).

CONCLUSIONS

The Two Layer Method for locally procured human pancreata with cold ischemia time lower than 8 hours offers significant advantage over UW cold storage increasing the pancreatic islet isolation yield and the isolation success rate.

Infectious tolerance mediated by CD8+ T-Suppresor Cells After UV-B–irradiated donor-specific transfusion and rat heart transplantation

AIMS

CD8+CD28- human T-suppressor cells (Ts), which can be generated in vitro, act directly on APC rendering them tolerogenic to unprimed and primed CD4+ T cells. The aim of this study was to investigate the possibility that CD8+ T cells mediate the induction of tolerance in a heart transplantation model in rodents.

MATERIALS AND METHODS

Blood from Lewis rats was UV-B-irradiated and transfused into ACI recipients on days -21, -14, and -7 before heart allograft transplantation on day 0. CD4(+) and CD8(+) T cells were positively selected from ACI rats, which had tolerated Lewis heart allografts for more than 100 days and were adoptively transferred to naive ACI rats pretreated (day -1) with gamma irradiation. These ACI rats underwent transplantation with Lewis hearts 24 hours after adoptive transfer of putative T-suppressor cells.

RESULTS

Adoptive transfer of CD8(+) T cells from tolerant ACI to naive ACI rats significantly prolonged Lewis heart mean allograft survival time (MST +/- SD) to 69 +/- 13 days as compared with 15 +/- 1 and 14 +/- 1 days in animals adoptively transferred with CD4+ T cells or untreated controls, respectively (P < .001). Similarly, adoptive transfer of CD8(+) T cells from secondary ACI recipients to naive syngeneic animals also significantly prolonged survival of heart allografts to MST +/- SD of 72 +/- 4 for CD8(+) and 15 +/- 4 days for CD4(+) T cells (P < .001).

CONCLUSIONS

These data demonstrate that allogeneic tolerance induced in ACI recipients by treatment with UV-B-irradiated blood from Lewis donors is mediated by CD8+ T-suppressor cells.

Factors influencing surgeons’ choice of method for hernia repair technique

Tension-free hernioplasty is performed using prosthetic material in one-half of hernia repair procedures in Poland but in 85% of those in the region of Pomerania. This questionnaire study of surgeons in Pomerania examined their sources of knowledge about and the factors influencing their choice of groin hernia surgery. The questionnaire was sent to surgeons from 19 hospitals and was answered by 109 (83% of hernia surgeons in the region). We analyzed their reported knowledge of particular operative techniques, factors important in selecting the technique (personal experience, trends in surgical center), and the available sources of information (e.g., medical literature, internet, information from teachers, sales representatives). All respondents reported being familiar with and able to perform tension-free techniques, but only 44% are influenced by their individual professional skills in selecting the technique. Another 44% base their decision on trends in their hospital, and only 22% consider the patient's preferences. The most frequently quoted sources of scientific information are articles in the medical literature and conference reports (90%). Only 8% of the respondents are governed in their professional work by information from pharmaceutical company representatives. Most surgeons (70%) would prefer to make a decision about using a new surgical technique after practical training sessions or workshops led by experienced colleagues. In contrast to common opinion, the information from sales representatives are of only minor importance compared to that of evidence-based data and attendance at workshops and courses.

A study of posttraumatic disorders in children who experienced an industrial disaster in the Briey region

OBJECTIVES

To study posttraumatic disorders in children who were directly and indirectly involved in an industrial disaster; to assess the respective impact of traumatism exposure, parental disorders and sociodemographic variables on the posttraumatic disorders of the children.

METHODS

The children were assessed with self-administered questionnaires (STAIC, CDI, IES) and questionnaires filled in by parents (CPRS, CBCL). Parents were assessed with the GHQ-28. Forty-three exposed children were compared with 44 children who were exposed to the same risk (indirectly exposed group) and with a control group of 50 unexposed children.

RESULTS

The exposed group obtained significantly higher anxiety and trauma-related scores than the control group and the threatened group, as well as higher scores of behavioural symptoms and of parental disorders. Indirectly exposed children did not have higher rates of symptoms than control children. The younger exposed children exhibited the highest psychopathological scores. Low sociodemographic status was associated with more disorders. There were no differences on questionnaire scores between girls and boys. Children's disorders correlated with disorders in both parents; but this only accounted for part of the variance, a finding which supports the hypothesis of a direct impact of the trauma on the child, irrespective of parental clinical status, SES of the family, children's age and gender.

CONCLUSIONS

Children's and parent's disorders interact in a complex fashion which needs further study.

[Long term results after surgical treatment of hepatolithiasis]

The paper presents a case of hepatolithiasis. Final diagnosis was established due to computed tomography and endoscopic recurrent cholangiopancreatography many years after the first symptoms' occurrence. Left hemihepatectomy was performed with very good 5-year result.

Free radicals generation by granulocytes from men during bed rest

Phagocytes (granulocytes and macrophages) are one of the most important sources of reactive oxygen species (ROS) in the human body. A stimulated phagocyte reaches within a dozen of seconds the functional state known as the respiratory burst. This phenomenon includes three interrelated processes: 1) a several fold increase in the oxygen uptake, 2) generation of large amounts of ROS, and 3) stimulations of glucose metabolism via the pentose phosphate shunt. The main ROS generated during phagocytosis is the superoxide radical anion O2-. The reaction of dismutation of O2- generates hydrogen peroxide (H2O2). O2- and H2O2 do not have strong cytocidal proerties but are supbstrates for the generation of more active biologically ROS, especially the hydroxyl radical (OH) and hypochlorous acid (HOCl). A stimulated phagocyte (especially neutrophil) generates also vast amounts of nitric oxide (NO-). NO- may react with the superoxide radical anion forming peroxynitrate (ONOO-). Reactivity of ONOO- is comparable to that of the hydroxyl radical. ONOO- plays probably a very important role in the so-called oxygen-dependent killing mechanisms during phagocytosis. The role of NO- in the process of phagocytosis is unclear. However, NO-, apart from other biological functions, inhibits aggregation and adhesion of blood platelets. Morevover, it seems to participate in the slefregulation of granulocyte cativity (probably limiting excessive inflammative reaction). Excess of ROS generated by phagocytes may damage biologically important macromolecules. Membrane lipids are particularly vulnerable to peroxidation. It leads to alterations in membrane fluidity and permeability. ROS excreted to the environment of a phagocyte may impair functions of other morphotic elements of blood (erythrocytes and thromobcytes) in this way. Bed rest covers two conditions: 1) limitation of motoric activity (hypodynamia) and 2) restraining the pressure on bones along parallelly to their long axes (hypogravia). Under bed rest conditions organism is subject to many harmful changes. I.a., bed rest affects also leukocyte functions. However, we were not aware of any sutdies concerning the effect of bed rest on the respiratory burst of granulocytes. This study was aimed at an examination of the effect of bed rest on the generation of O; and H2O2 by neutrophils (PMNL).

Effect of long term bed rest in men on enzymatic antioxidative defence and lipid peroxidation in erythrocytes

Bed rest is an integral part of treatment of numerous diseases. Typical examples are bone fractures of lower extremities and pelvis. Temporary immobilization is necessary also, e.g., in heart diseases (stroke), backbone and imminent abortion. The sick organism spares energy during the bed rest wich is beneficial. However, bed rest results in many alterations which are disadavantageous. They concern the function of almost all organs and systems but affect most significantly the locomotor and ciruclatory systems. Bed rest brings also about changes in the composition of peripheral blood and functions of the morphotic elements of blood. Red blood cells are subjected to the action of large amounts of reactive oxygen species (ROS). During oxidation of hemoglobin to methemoglobin superoxide radical anion (O2-) is formed: HbFe2+ + O2 --> MetHbFe3+ + O2- (1) Ferrous and ferric ions present in the cytoplasm of red blood cells may be catalysts of the Fenton reaction leading to the production of the hydroxyl radical: O2- + Fe3+ --> O2- + Fe2+ (2) Fe2+ + H2O2 --> Fe3+ + OH + HO- (3) OH shows a tremendous reactivity. It may react with lipids, proteins, nucleic acids and carbohydrates. The process of lipid peroxidation is best understood. It concerns mainly polyunsaturated fatty acids present in cell membranes. Peroxidation of membrane lipids decreases membrane fluidity and impairs its barrier function. The lowered membrane fluidity compromises erythrocyte deormability which in turn disturbs oxygen delivery to the tissues. End productions of lipid peroxidation are low-molecular wieght compounds, among them carbohydrates (ethane and pentane) and aldehydes, e.g. malondialdehyde (MDA). MDA concentration is an acknowldeged marker of the intensity of lipid peroxidation. Erythrocytes contain a complex system of protection against the action of ROS. It includes various enzymatic and non-enzymatic mechanism. The most important antioxidative enzymes of the red blood cells are superoxide dismutase (Cu,Zn-SOD, EC 1.15.1.1) catalase (CAT, EC 1.11.1.6) and glutathione peroxidase (GSH-Px, EC 1.11.1.9). Cu,Zn-SOD catalyzes the dismuation of O2- to hydrogen peroxide (H2O2). Catalase and peroxidase remove H2O2 and, moreover, GSH-Px can reduce lipid peroxides. Under normal conditions an equilibrium exists between the formation and removal ROS. If ROS are formed in excess or the defensive antioxidative mechanism are inefficient, oxidative stress develops. Derangement of the equilibrium between the formation and removal of ROS is important in the pathosgenesis of many diseases, e.g. atherosclerosis, diabetes, Down syndrome and Alzheimer disease. There are literature data on disturbances of enzymatic antioxidant defense mechanism of blood plateless during bed rest. This study was aimed at an examination of the post-traumatic bed rest on the enzymatic antioxidative defense mechanisms and lipid peroxidation in erythrocytes.

Comparison of oxidative base damage in mitochondrial and nuclear DNA

The levels of endogenous pig liver cells mitochondrial DNA oxidative base damage have been investigated using isotope dilution gas chromatography mass spectrometry (GC/MS). Higher levels of five measured bases were found in mtDNA in relation to nuclear DNA. We have also detected large differences in the modified base ratios of mitochondrial versus nuclear DNA. These ratios for the bases with promutagenic properties as 8OHGua and 5OHCyt are much lower than for other bases (5OHHyd, 5OHMeHyd, 5OHMeUra).

[Treatment results for inguinal hernia repair with the mesh-plug method]

In the years 1992-1996 367 operations were performed in 350 patients aged 15-88. The type of the hernia was classified according to Gilbert's classification in Rutkow's modification. Type 2 and 3 was the most often (136 and 102 patients respectively). Recurrent hernia after classical operations were treated in 33 patients. Local, epidural or subarachnoid anesthesia was applied in 93% of patients In 75% of patients no analgetics were administered within first 24 hours after operation. In the remaining only traditional analgetics were given. Early complications were noted in 6 patients: wound infections, scrotal oedema, hydrocele. The time of operation was 35 minutes and the time of hospitalization was 2-5 days. Patients returned to their normal activity within 2 weeks. In the follow up period 1-5 years only 2 recurrences of hernia were noted (0.5%).

[Mesh-plug operation for treating inguinal hernia. Randomized studies]

In the period from October 1996 to April 1997 a prospective randomized study of one hundred patients with inguinal hernia was performed. 50 patients underwent the Bassini procedure (group I) and others tension-free mesh-plug repair (Lichtenstein in Rutkow's modification) (group II). The type of hernia was classified according to Gilbert's classification in Rutkow's modification. We used t- Student test and Mann-Whitney's test to evaluate significant differences. There was no significant difference in patients' age, types of hernia or the type of anesthesia between to groups. The time of operation was significantly shorter in group II (median 51.8 min) than in group I (median 63 min). During the post operative period more patients from group I required narcotic analgetics (64% versus 22%). The rate of complications was similar (8% and 6% respectively). Hospital stay was significantly shorter in group II-median 4 days versus 6 days in group I. Rehabilitation to normal activity and return to work was also shorter in group II-median 2 weeks versus 3 weeks (not statistically significant). During the follow up period 1-17 months no recurrences were observed.

[Diagnosis of pancreatic neoplasm--possibilities and limitations]

75 consecutive patients treated for pancreatic cancer were submitted to prospective trial. 1 to 12 weeks passed from the onset of symptoms before diagnosis was established. 61 (81%) patients were admitted due to symptoms and 14 (19%)--due to USG findings. Sensitivity and selectivity of imaging techniques was as follows: USG-87% and 73%, ERCP-72% and 72%, CT-100% and 82% respectively. Staging of the lesions estimated by CT (AJCC/TNM scale) 34 patients qualified as stage I, 15 as stage II, 14 as III and 12 as stage IV. Surgery was undertaken in 71 patients and resective procedures in 32 of them (43%). The final diagnosis was established by one biopsy in 21 patients, and in the further 8 cases 2-3 biopsies were necessary. In 3 cases cancer cells were found only during histological examination of the whole resected specimen. The follow up in resected group was 1-30 months. One year survival was 72%, actuarial survival is 38%.

[Is it possible to have a medical definition of family crisis?]

In our contemporary society, the traditional multi-generational family has to adapt and to organize itself around a smaller nucleus: "The nuclear family". Nowadays, the management of the crises which accompany significant Life Events (such as birth, marriage, retirement, death...) within this new family-system, is refrained by the lack of "relays" which were previously provided by the "enlarged family". In the absence of available relatives (that is, grandparents, cousins, etc...), it is now the Medical System which is addressed with the demand for help. Using worthy contributions of the systemic theories, the authors analyze the ambiguity of such a request and the paradox underlying it, namely, to take care of a "normal" family crisis. They emphasize two major dangers consisting of the "designation" of an identified patient and the risk of "phagocytosis" of the therapeutic system by the family system.