The investigation of interspecies diversity of erythrocyte aggregation properties by two different photometric methods in four animal species.

Among the haemorheological parameters, red blood cell (RBC) aggregation shows the largest interspecies diversity, and often controversial data can be found in the literature, besides the methodology-dependent issues. In this present investigation, we compared four experimental/laboratory animal species' RBC aggregation by two different photometric methods for better revealing the differences. Blood samples (K3-EDTA, 1.5 mg/ml) were taken from female animals: 16 inbred mice (Mus musculus, cardiac puncture), 15 outbred rats (Rattus norvegicus, caudal caval vein puncture), 15 beagle dogs (Canis canis, cephalic vein) and 23 juvenile pigs (Sus scrofa domesticus, medial saphenous vein). Haematological parameters (microcell counter) and RBC aggregation (light transmission and syllectometry-laser backscatter methods) were determined within 2 h after sampling. Describing the first 5-10 s of the aggregation process, additional parameters were calculated out of the syllectometric raw data. Standardized difference was calculated to determine the sensitivity of the two devices. Parameters describing the extent and magnitude of red blood cell aggregation showed the lowest values in the rat and the highest in the pig and canine blood. In turn, parameters describing the kinetics of aggregation showed the lowest values in the mouse and the highest in the rat. The standardized difference values for the laser backscattering method were 2-4 times larger vs. the light transmission one. The magnitude of the differences was not consequent in the aggregation parameters. These comparative results show that the laser backscattering method can detect the RBC aggregation differences between the investigated species more sensitively than the light transmission method.

Neurolymphomatosis as a late relapse of non-Hodgkin's lymphoma detected by 18F-FDG PET/CT: a case report / Neurolinfomatosis como recaída de un linfoma no Hodgkin detectada con 18F-FDG PET/TAC: a propósito de un caso

Neurolymphomatosis is a rare condition defined as an infiltration of nerves, nerve roots or nervous plexuses by haematological malignancy. Its diagnosis may sometimes be difficult with conventional imaging techniques. This paper aims to emphasize the importance of this entity and the role of 18F-FDG PET/CT in this indication. We present the case of a 53-year-old male who complained of sharp pain in his right hip and right leg paresthesia after 2 years of complete remission from Non-Hodgkin's lymphoma. Physical examination and CT scan were negative and the lumbar MRI showed protrusion of L5-S1 disc. Physiotherapy, nonsteroid antiinflammatory drugs and steroids were inefficient. PET/CT was performed four months after the onset of the symptoms, revealing focal FDG uptake in the right S1 nerve root and linear FDG uptake along the right sacral plexus suggesting relapse. This was confirmed by histology (AU)

La neurolinfomatosis es una entidad rara definida por la infiltración de los nervios, raíces o plexos nerviosos por un proceso hematológico maligno, siendo en ocasiones difícil de diagnosticar mediante técnicas de imagen convencionales. La finalidad del caso es llamar la atención sobre su importancia y el papel de la 18F-FDG PET/TAC. Presentamos el caso de un varón de 53 años con dolor en la región de la cadera derecha y parestesias en la pierna derecha tras 2 años de remisión completa de un linfoma no Hodgkin. El examen físico y la TAC fueron negativos, mostrando la RM lumbar una protrusión discal en L5-S1. El tratamiento con fisioterapia y con antiinflamatorios no esteroideos y esteroideos fue ineficaz. La PET/TAC realizada a los 4 meses reveló una captación focal de FDG en la raíz del nervio S1 derecho y una captación lineal a lo largo del plexo sacro derecho sugestivo de recaída del linfoma, lo que fue confirmado por la histología (AU)

Neurolymphomatosis as a late relapse of non-Hodgkin's lymphoma detected by 18F-FDG PET/CT: a case report.

Neurolymphomatosis is a rare condition defined as an infiltration of nerves, nerve roots or nervous plexuses by haematological malignancy. Its diagnosis may sometimes be difficult with conventional imaging techniques. This paper aims to emphasize the importance of this entity and the role of (18)F-FDG PET/CT in this indication. We present the case of a 53-year-old male who complained of sharp pain in his right hip and right leg paresthesia after 2 years of complete remission from Non-Hodgkin's lymphoma. Physical examination and CT scan were negative and the lumbar MRI showed protrusion of L5-S1 disc. Physiotherapy, nonsteroid antiinflammatory drugs and steroids were inefficient. PET/CT was performed four months after the onset of the symptoms, revealing focal FDG uptake in the right S1 nerve root and linear FDG uptake along the right sacral plexus suggesting relapse. This was confirmed by histology.

Inter-species differences in hematocrit to blood viscosity ratio.

Hematocrit (Hct) is the major determinant of whole blood viscosity and of its oxygen binding capacity: with increasing Hct, viscosity increases exponentially and oxygen capacity increases linearly. Thus, the theoretical oxygen transport potential of blood, as indexed by the ratio of Hct to viscosity (Hct/viscosity), generally yields a curve concave to the Hct axis with a maximum at an "optimal hematocrit" value. This study analyzed relations between Hct, blood viscosity and shear rate for rats and dogs to explore whether different optima exist for Hct or Hct/viscosity. Our results reveal differences depending on both shear rate and species: at equal Hct, rats had higher blood viscosity and thus lower Hct/viscosity levels. Optimum values for Hct/viscosity were markedly different between the two species at shear rates of 90 and 200 s-1. Conversely, Hct/viscosity data at 10 s-1 did not exhibit an optimum but rather a linear decrease of the ratio with increasing hematocrit. Relations between Hct and blood viscosity thus differ among animal species. Inasmuch as animal studies are often utilized as an aid to understanding hemorheological aspects of clinical conditions and/or therapy, evaluating Hct/viscosity ratios may be a useful supplementary tool for research focused on various physiological and patho-physiological processes.

Hemorheological changes caused by intermittent Pringle (Baron) maneuver in beagle canine model.

In liver resection operations the Pringle (Baron) maneuver can be used for temporary ischemia by clamping the hepatoduodenal ligament intermittently. In this beagle canine model we investigated whether hemorheological parameters may alter in systemic, portal and hepatic venous blood and in arterial samples during-after Pringle maneuvers. In Pringle Group unilateral femoral artery and external jugular vein were cannulated. From median laparotomy the hepatoduodenal ligament was exposed. The portal venous system was catheterized via a mesenteric vein and through the inferior caval vein a catheter was led to the hepatic veins. After stabilization, a 15-minute Pringle maneuver was carried out three times with 5-minute interpolated reperfusion periods. In Control Group Pringle maneuvers were not made. Before and after Pringle maneuvers parallel blood samples were taken from the cannulated vessels for determining hematological parameters and erythrocyte aggregation. Following Pringle maneuvers erythrocyte deformability, blood and plasma viscosity were also tested. The results showed that besides systemic hemorheological effects of the intermittent Pringle maneuver local leukocyte count, hematocrit and erythrocyte aggregation index altered mainly in portal venous blood, depending on the repeating number of the maneuvers. Thus, investigations of hemorheological parameters might be useful to determine the optimal duration of the Pringle maneuver.

Esophageal replacement using cryopreserved tracheal graft.

Esophageal replacement using artificial material is not a new concept. Prior experiences with prostheses, allografts and composite grafts have not proved particularly successful. The aim of this study is to investigate whether cryopreserved animal trachea is suitable for the replacement of the esophagus. In 12 beagle dogs a 6-cm-long segment of the cervical esophagus was removed, and was replaced with cryopreserved trachea, which had been stored for 21 days on -86 degrees C. The proximal and distal ends of the esophagus were joined together with the graft by simple continuous suture (Biosyn 3/0) and covered with the sternohyoid flap. Postoperatively 16 hematological parameters were measured. The dogs were planned to be euthanized at random on days 28, 42 and 56 after the operation. Tests for air leak were performed and the inner diameter of the graft was measured to detect shrinkage. The microscopic structure of the graft was analyzed using haematoxylin and eosin staining. There was no indication of insufficiency. Based on the air leak test the sutures withheld properly. The inner diameter of the graft narrowed from an average 19 mm (+/- 1 mm) to 15.8 mm (+/- 0.6 mm). In length, the graft shortened from an average 60 mm to 47 mm (+/- 3 mm). No feeding difficulty was observed. In two cases wound suppuration was found involving only the cutaneous and subcutaneous layers. Concerning the laboratory parameters, only the fibrinogen level and white blood cell count showed temporary although significant changes. Histology findings on the 56th day showed absolute integration of the trachea with the esophagus, with disintegration of the tracheal cartilages. Cryopreserved trachea seems to be suitable for the replacement of a 5-6-cm-long esophageal segment.

The effects of renal ischemia-reperfusion on hemorheological factors: preventive role of allopurinol.

Changes in hemorheological parameters were studied in dogs following unilateral renal artery clamping (45-minute ischemia then reperfusion), with and without preoperative administration of allopurinol. Sham-operated animals were also evaluated. Blood samples were collected preoperatively, at beginning and at 30, 60 and 120 minutes of reperfusion, then on the 1st, 3rd, 5th and 7th days. Filtration properties of erythrocytes (relative cell transit time, RCTT), whole blood and plasma viscosity (WBV, PV), fibrinogen level and hematology parameter were determined. RCTT significantly increased for both ischemic groups at 30 minutes of reperfusion, and remained elevated on the 1st and 2nd postoperative days; these changes were abolished by allopurinol pretreatment. WBV and hematocrit increased on the 1st day, and PV and fibrinogen level showed elevation on 1st-5th postoperative days. We thus conclude that decreases of RBC deformability (i.e., higher RCTT) were characteristic and specific on early postoperative days after renal ischemia-reperfusion and that these alterations were prevented by pre-ischemia administration of allopurinol.

Temperature gradient between brain tissue and arterial blood mirrors the flow-metabolism relationship in uninjured brain: an experimental study.

BACKGROUND: The purpose of the present experimental study was to determine the feasibility and usefulness of brain temperature measurement (T(br)) and the calculated difference between brain temperature and arterial blood temperature (DeltaT(br-a)) in uninjured brain during variations of cerebral perfusion pressure (CPP) and concomitant changes of the regional cerebral blood flow (rCBF). METHODS: Nine anaesthetized pigs were subjected to controlled CPP decrease to assess the lower cerebral autoregulation threshold. A parenchymal intracranial pressure (ICP) sensor combined with a microthermistor for temperature measurement, a miniaturized Clark-type electrode measuring brain tissue oxygenation (p(ti)O(2)), a small flexible intraparenchymal thermodilution probe for measuring rCBF and cerebral microdialysis were inserted carefully in the frontal white matter. RESULTS: Analysing the p(ti)O(2) during controlled CPP decrease, we found significant breakpoints of p(ti)O(2) at a CPP of 40 mmHg and 20 mmHg, related to an rCBF of 20 ml/100 g/min and approximately 10 ml/100 g/min. Similarly, the relationship between DeltaT(br-a), and CPP or rCBF revealed a characteristic increase of DeltaT(br-a) in the negative direction up to more than -0.30 degrees C assuming a strong flow dependency. CONCLUSION: The temperature difference between brain tissue and arterial blood DeltaT(br-a) mainly reflects the cerebral blood flow-brain tissue oxygenation-metabolism relationship as far as the estimation of the individual lower cerebral autoregulation threshold.

Adhesion formation with open versus laparoscopic cholecystectomy: an immunologic and histologic study.

BACKGROUND: This randomized study aimed to compare the reaction of the immune system to the process of postoperative adhesion formation after open and laparoscopic cholecystectomy. METHODS: In this study, 20 mongrel dogs were used: 10 each in the laparoscopic and open cholecystectomy groups. Blood and peritoneal lavage samples were taken up to postoperative day 14, followed by second-look laparoscopy and reoperation to detect the rate of adhesion formation. Also, specimens were obtained from the liver bed for histology. RESULTS: In the open cholecystectomy group, the white blood cell count was higher in blood samples and lower in lavage specimens. Adhesion formation was extensive, and the histologic immune reaction was more intensive in the open cholecystectomy group. CONCLUSION: This randomized study proved that laparoscopic cholecystectomy was associated with less immune suppression, less inflammatory reaction, and therefore less adhesion formation than open cholecystectomy.

Effects of sex hormones on ECG parameters and expression of cardiac ion channels in dogs.

AIM: The aim of the study was to examine the effects of testosterone and oestrogen on the ECG parameters and expression of cardiac ion channels in male and female dogs, and to compare the dofetilide-induced lengthening of QTc interval in control, castrated and hormone-treated animals. METHODS: ECG records were taken from male and female anaesthetized dogs (n = 10 in each group) before castration, after castration, and following inverted hormone substitution. The animals were challenged with dofetilide at each stage of the experiment. Finally, the hearts were excised and expression of ion channels was studied using Western blot technique. RESULTS: Heart rate was decreased and PQ interval increased by deprivation of sex hormones in both genders (orchiectomy or ovarectomy), while inverted hormonal substitution restored control values. Orchiectomy significantly increased the duration of QT and QTc intervals, QTc-dispersion and the dofetilide-induced lengthening of QTc, while testosterone treatment of castrated females had opposite effects. Intraventricular conduction (QRS duration) was independent of the endocrine status of the animals. Ovarectomy or oestrogen treatment of castrated males failed to alter significantly these parameters except for QTc-dispersion. Expression of ion channel proteins responsible for mediation of I(K1) and I(to) currents (Kir2.1 and Kv4.3, respectively), was significantly higher in the testosterone-treated castrated females and normal males than in the oestrogen-treated castrated males and normal females. CONCLUSION: Repolarization of canine ventricular myocardium is significantly modified by testosterone, but not oestrogen, in both genders. This effect is likely due to augmentation of expression of K(+)-channel proteins, and thus may provide protection against arrhythmias via increasing the repolarization reserve.

Local and systemic hemorheological effects of cerebral hyper- and hypoperfusion in a porcine model.

Using a well defined pig model, we investigated whether cerebral hypertension and hypotension influence hemorheological factors. After surgical preparation and stabilization, periods of hyperventilation, controlled periods of cerebral perfusion pressure increases and decreases were utilized. After each period, blood samples were collected from the cannulated femoral artery and vein, and from the superior sagittal sinus. Erythrocyte deformability, whole blood and plasma viscosity and hematological parameters were determined. Erythrocyte deformability significantly worsened in arterial samples after hypertension and hypotension, and in sinus samples it was impaired after hypotension period. Hematocrit significantly increased in arterial and sinus samples during hypertensive period, accompanied by similar alterations in whole blood viscosity. We conclude that hemodynamic changes caused by hyperventilation, hyper- or hypotension can influence hemorheological factors, and suggest that the rheological alterations can affect local hemodynamic and metabolic conditions.

A new concept for esophageal resection--prevascularization: an experimental study.

We aim to elaborate upon a basically new animal model for esophageal resection. A total of 17 operations on 10 dogs were performed in order to develop a model in which resection of the cervical part of the esophagus involves two steps. The first step comprises omental flap transplantation from the abdomen to the cervical region by a microsurgical method, this omental flap improving the blood supply to the organ (prevascularization). The second step is segmental resection of the esophagus 14 days later. Of the five transplanted grafts, four still survived one week after the operation; for technical reasons, one flap had thrombotized. In the two long-term survival cases with esophageal resection after prevascularizastion, there were no major complications: the resections were successful, and the omental flap 'grew into' the tissue structure of the esophagus, assisting the healing of the anastomosis. Segmental resection of the cervical part of the esophagus was performed successfully via a new type of operation on dogs.

Systemic and regional hemorheological consequences of warm and cold hind limb ischemia-reperfusion in a canine model.

We have studied systemic and regional changes in hemorheological parameters after complete acute limb ischemia and reperfusion (I/R) in 24 mongrel dogs. Unilateral cooled and non-cooled vascular ischemia (3 h)-reperfusion (4 h), and sham-operations were performed. Blood samples were collected from the excluded region, during reperfusion and for 5 days. Whole blood and plasma viscosity (WBV, PV), relative cell transit time (RCTT) of erythrocytes, fibrinogen level and hematological parameters were determined. In I/R groups WBV of excluded blood was significantly higher compared to the base (p < 0.05), and RCTT increased during the reperfusion. On 2nd-3rd days RCTT increased significantly in both I/R groups. In each group PV and fibrinogen showed continuous increase during the postoperative period, prominently in cooled I/R group, and furthermore WBV corrected for hematocrit (40%) was the highest in cooled I/R group. These suggest that surgical acute limb I/R may cause hemorheological changes, which are more serious after cooling. (Grants: OTKA-T032571, 6003/1/2001/ETT.)

Experimental examination of the healing process of telescopic esophageal anastomosis.

The basis of telescopic anastomosis is old, only the practical details of it have changed and improved. The telescopic anastomosis technique is successfully applied in our practice for reconstruction of gastrectomy and esophageal resection. The reason for this study was that data about the healing process of telescopic anastomosis had not been found in the literature. We used four groups of mongrel dogs for our experiments: Group A (n = 3) received 20 mm-long invaginations with a survival time of 7 days; Group B (n = 3) received 10 mm-long invaginations with a survival time of 21 days; Group C (n = 3) received 20 mm-long invaginations with a survival time of 21 days; Group D (n = 3) received 30 mm-long invaginations with a survival time of 21 days. At the end of the above survival times we removed the anastomosing area, measured the bursting pressures and performed morphological and histological examinations. In each case we also performed an anastomosis exactly the same as a completely healed anastomosis and its pressure tolerance was measured (0 day). The pressure tolerance within the anastomosis rises gradually and independently of the length of the invaginated esophageal part. Anastomosis leakage did not occur. The invaginated esophageal part did not suffer any damage. The muscular wall of the intragastric part of the esophagus became covered by the mucosa of the stomach during the healing process and it joined with the esophageal mucosa at the edge of the free end of the esophagus.

Brain tissue oxygen monitoring for assessment of autoregulation: preliminary results suggest a new hypothesis.

Brain tissue oxygen monitoring (P(ti)O2 (Neurotrend, Codman, Germany) was employed in addition to standard intracranial pressure (ICP) and cerebral perfusion pressure (CPP) monitoring in seven patients with severe neuronal damage of heterogeneous etiology. The correlation between P(ti)O2 changes and CPP fluctuations during periods of 30 minutes were analyzed, when CPP was above 70 mmHg and lower than 100 mmHg. A new ratio, the CPP-oxygen-reactivity (COR) index was calculated as COR=delta p(ti)O2 %/delta CPP%. The patient COR values were compared to those found in the brain of six noninjured anesthetized piglets. The analysis was performed to determine the significance of synchronous fluctuations of CPP and P(ti)O2, when CPP is above the lower threshold of autoregulation. The correlation between CPP variations and p(ti)O2 variations was found to be strong (R(mean)) = 0.74 +/- 0.17) in the patients and was weak in the uninjured animals (R(mean)) =0.38 +/- 0.43). The COR (mean) was 2.05 +/- 0.57 in patients and 0.78 +/- 0.6 in the animals. In the injured brain of our patients, we observed an unexpectedly close correlation between P(ti)O2 and CPP variations when CPP levels were within a therapeutically targeted range (70 to 100 mmHg). In a porcine model, we could not find this relationship in the noninjured brain. We speculate that an increased COR might be indicative for an impaired local pressure autoregulation. The preliminary data suggest that COR values above "1" might be pathologic. However, the reported sample sizes are too small to provide sufficient statistical power to justify inferential statistical analyses. As such, results are presented with descriptive statistics only, and should be regarded as a hypothesis.

[Data about the early physical reliability of hand-sewn anastomoses in esophagectomy and gastrectomy]. / Adatok a nyelócsó és a gyomor reszekciós mútéteinél kézzel varrt anasztomózisok korai fizikai varratbiztonságához.

We examined on models the inner pressure tolerance of the most frequently performed single layer anastomoses used in esophagectomies and gastrectomies. The aim was to examine whether interrupted or continuous suture proves safer immediately after the operation. We investigated the difference between sutures involving and not involving the mucosa. The anastomosis models were of organs of hybrid pigs slaughtered in the meet-industry. Atraumatic, 3/0 Biosyn suture material was used. The bursting pressure was measured by insufflating CO2 gas. Its bursting pressure can characterize the inner pressure tolerance of an anastomosis. The circumstances of the experiment, the suture technique and the examination of the bursting pressure were standardized. Our considerations are: 1. The early inner pressure tolerance of an anastomosis does not depend on the condition of the wall. The critical factor is their ability to expand. 2. The inner pressure tolerance of continuous sutures is better than of interrupted ones if the tissues in the suture line show similar degree of dilatation. Optimal conditions are achieved with end-to-end or side-to-side anastomoses of single organs (for example between small bowel and small bowel or colon and colon). 3. Involving the mucosa in the stitches has not influenced early physical suture certainty.

[Experimental model for the examination of inner pressure tolerance of telescopic anastomosis and other frequently performed anastomosis types of the esophagus]. / Nyelócsóvel készült süllyesztett és más gyakrabban alkalmazott anasztomózis változatok belsó nyomástúrésének vizsgálata modellkísérletekben.

We have good results with telescopic anastomosis technique in partial oesophagectomies and gastrectomies. As we could not find data about the healing process of telescopic anastomoses so we started experimenting. Inside pressure tolerance was examined immediately after performing anastomoses by measuring the bursting pressure using the organs of pigs slaughtered in the meat industry. Both oesophago-gastrostomies and oesophago-jejunostomies were performed with telescopic, single layer interrupted, single layer continuous, double layer interrupted and double layer continuous-interrupted technique, 9 of each anastomosis. A series of oesophago-jejunostomies were performed with EEA stapler. 99 anastomoses of 11 types were investigated. We found, that the inner pressure tolerance of telescopic oesophago-gastrostomy is better than any other single layer type variant. On the other hand the double layer type variants have much better pressure tolerance than the telescopic and other two type single layer anastomoses. The difference is statistically significant. In oesophago-jejunostomies the pressure tolerance of telescopic anastomosis is better than of the single layer interrupted type but the difference between the telescopic and single layer continuous type anastomoses is not significant. The pressure tolerance of double layer anastomosis is higher than the telescopic one but the difference is significant only in the continuous-interrupted type. The inner pressure tolerance of telescopic and EEA stapler anastomoses are equal. The investigation of additional features in anastomosis healing is in progress.

Basic teaching in microsurgery.

We summarize our 15 years of educational experience in the field of teaching microsurgery. The students can be divided into three groups: (1) medical students, (2) researchers, (3) medical doctors and specialists. Characteristics of our method include the following: activity, synchronism, video-assistance, self-controlling, individualization, analysis. The Furka microsurgical educational method, named after one of the authors, is 20 hours long (five 4-hour sessions). The first lesson allows students to become acquainted with the microsurgical instruments. The next lesson consists of learning the probe of layer-feeling. The third lesson is to learn how to produce stitches under the microscope. The fourth lesson includes arterial anastomosis preparation on fresh arterial pieces of animal origin. The fifth lesson means a quality change from previous classes, as practice is performed on living animals, generally rats. The teaching of microsurgical basics requires both patience and empathy. The teaching process is most successful if one teacher deals with a maximum of two students.

Spleen autotransplantation in mice: a novel experimental model for immunology study.

The aim of the experimental model to develop a spleen transplant model in mice to study the role of spleen in autoimmune and transplant rejection. After a midline incision, splenectomy was performed. Four tiny segments were cut from the removed spleen and were rinsed at room temperature in physiological salt solution. The greater omentum was lifted and four omental pockets were created; four thin segments were then placed into the "nests," subsequently marked, and fixed using 8-0 suture. The abdomen was then closed. The duration of the survival time was different among the nine groups (n = 3-3). Tissue samples were taken from the marked areas for histological examination stained with hematoxylin and eosin (H&E). H&E staining demonstrated large, well-circumscribed splenic nests with lymphoid zone and red pulp and well-formed trabecules in the spleen. Among the possible applications of this novel model is the ability to study the role of spleen in autoimmune and organ rejection.