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.

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.

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.

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.

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.

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.

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.

Comparison between continuous brain tissue pO2, pCO2, pH, and temperature and simultaneous cerebrovenous measurement using a multisensor probe in a porcine intracranial pressure model.

Local brain tissue oxygenation (p(ti)O2) and global cerebrovenous hemoglobin saturation (SjO2) are increasingly used to continuously monitor patients after severe head injury (SHI). In patients, simultaneous local and global oxygen measurements of these types have shown different results regarding the comparability of the findings during changes in CPP and ICP. This is in contrast to theoretical expectations. The aim of this study was to compare p(ti)O2 measurement with cerebrovenous oxygen partial pressure measurement (p(cv)O2) in an animal intracranial pressure model. To this end, a multisensor probe was placed in the left frontoparietal white matter to measure p(ti)O2, pCO2 (p(ti)CO2), pH (pH[ti]), and temperature (t[ti]) while simultaneously measuring these same parameters (p(cv)O2, p(cv)CO2 pH(cv), t[cv]) in the sagittal sinus of 9 pigs under general anesthesia. By stepwise inflating a balloon catheter, placed in supracerebellar infratentorial compartment, ICP was increased and CPP was decreased. The baseline levels of p(ti)O2, p(ti)CO2, and pH(ti) in the noninjured brain tissue showed more heterogeneity compared to the findings in cerebrovenous blood. Both, p(ti)O2 and p(cv)O2 were significantly correlated to the induced CPP decrease. PCO2 was inversely correlated to the course of CPP in both measurement compartments. Temperature measurement showed a positive correlation with CPP in both compartments. These findings demonstrate that brain tissue oximetry and cerebrovenous PO2 measurement are sensitive to CPP changes. The newly available continuous parameters in multisensor probes could be helpful in interpreting findings of cerebral oxygen measurement in man by analyzing the interrelationship of these parameters.

The influence of intraoperative complications on adhesion formation during laparoscopic and conventional cholecystectomy in an animal model.

BACKGROUND: The aim of this study was to evaluate the extent of postoperative adhesion formation after laparoscopic and open cholecystectomy. MATERIALS AND METHODS: Qualified surgeons performed 60 experimental laparoscopic cholecystectomies (LC) in dogs with the aim to acquire the laparoscopic technique. To assess the relation between the complications during the operation (bleeding, laceration of the liver bed, or gallbladder perforation) and the formation of adhesions, surviving animals were divided into four groups according to the type of complication occurred. Assessment of the results was made by second-look laparoscopy 4 weeks after LC using the adhesion index (AI; score range, 0-4). The animals then were killed so the extent of adhesion formation could be measured. As a control, open cholecystectomy was performed in 15 dogs without intraoperative complications. The Mann-Whitney rank-sum test and Dunn's method were used for statistical analysis. RESULTS: No adhesion formation or intraoperative complications were registered in the laparoscopic group I. In all the cases wherein bleeding or laceration of the liver bed occurred and was managed with electrocoagulation, adhesions formed. Adhesion formation in these groups was significantly higher than in "ideal LC" or cases of gallbladder perforation alone (p < 0.01). All the animals in the control group developed significantly more adhesions than those in the experimental group (p < 0.05). CONCLUSIONS: It seems that LC has a lower rate of adhesion formation than the conventional open technique. Complications such as bleeding or laceration of the liver bed during LC can enhance adhesion formation. No adhesion formation can be mentioned in relation to gallbladder perforation during LC.

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.

Protecting effects of intravenous insoluble glycogen treatment on the experimental necrotizing acute pancreatitis of dogs.

BACKGROUND/AIMS: We have studied the effects of insoluble glycogen applied intravenously on the experimental acute pancreatitis of dogs. METHODS: Experimental acute pancreatitis was induced by olive oil injected into the main pancreatic duct. The effects of insoluble glycogen were evaluated histologically and by measurements of levels of amylase, lipase in sera. The binding of endotoxin and secretable phospholipase A2 by insoluble glycogen were tested by isotopically labeled materials. RESULTS: Application of insoluble glycogen had beneficial effects on the experimental acute pancreatitis of dogs. CONCLUSION: The binding capacity on endotoxin and secretable phospholipase A2 could play the main role in the protection offered by insoluble glycogen.

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.)

Use of absorbable material for the closure of experimental longitudinal nephrotomy.

Large nephrotomy incisions made in 15 dogs were closed by sewing up the cavity system with stitches of 5/0 catgut and by sealing the renal parenchyma with tissue adhesive being pinpointed at the opened vessels. The incision was covered with a preparation of oxidized cellulose which was then likewise impregnated with tissue adhesive. This technique was found rapid and convenient and provided for adequate haemostasis. Its essential advantage lies in eliminating the deep through-and-through sutures involving a major loss of functioning renal parenchyma. All substances used were absorbed in due time.

[Autologous spleen transplantation]. / Lép autotransplantatio.

Splenectomy is known to increase the risk of overwhelming bacterial infection. There is a decrease in immunoglobulin IgM, T-lymphocytes, impaired primary antibody response to antigen challenge, an altered opsonic function and a tuftsin deficiency. Splenic autotransplantation has been suggested as a method of preserving function and this concept is supported by experiments in animals (dogs). The study describes autotransplantation of the traumatized spleen in human beings for the preservation of splenic function. Eleven patients operated on for abdominal trauma in the Kenézy Hospital in Debrecen, required total splenectomy, than splenic autotransplantation. In these patients splenic slides were implanted in between two layers of omental pouch (Furka's "spleen chip"). In 10 patients the follow-up radionuclid imaging, the IgM level, and the tuftsin level unambiguously confirmed the functioning of the splenic tissue.

[Various clinical patterns of relapsing polychondritis in six cases]. / Polychondritis recidivans sokszínú klinikai megjelenése hat eset kapcsán.

Relapsing polychondritis is a relatively rare disease characterized by episodic inflammation and progressive destruction of cartilage involving ears, nasal and laryngotracheal cartilage, cardiovascular system and the eyes. The increasing awareness of its clinically distinct has resulted in recognition of at least 550 reported cases. Six cases are reported to demonstrate the wide variety of clinical pattern. The most common features of the disease are auricular and nasal cartilage inflammation and nondeforming arthritis. Ocular symptoms and vasculitis is relatively rare. Two cases of relapsing polychondritis with laryngotracheobronchial manifestations illustrate the severe clinical features of the disease. Relapsing polychondritis may associate with diverse forms of connective tissue disease, such as rheumatoid arthritis. It seems interesting to note the onset in childhood. Treatment has been primarily symptomatic. In situations of mild symptoms, initial treatment is with nonsteroidal antiinflammatory drugs. For cases with serious manifestation, corticosteroids and immunosuppressants are indicated.

Experimental dermatoplasty of skin defects with an absorbable bioplastic preparation.

Experimental dermatoplasty was performed with fibrin sponge preparation in the rabbit, during the course of which the whole skin thickness was substituted. The fibrin sponge was fixed to the skin-edges with surgical adhesive. The gradually absorbed fibrin was replaced by the migrating epithelium such that epithelization developed gradually. In special cases this method can be recommended for clinical purposes.

Sutureless closure of the renal wound surface by extracorporeal renal surgery on dogs.

The authors have elaborated a sutureless method of closing the wound surface in order to preserve the renal parenchyma. They have used oxydized cellulose net (Surgicel) and tissue adhesive (Histoacryl-N-blau) to hold together the cut surface of the kidney at renal hypothermy (bench surgery) on dogs.

[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.

[How do intraoperative complications effect adhesion formation after laparoscopic cholecystectomy: a comparative animal study]. / Az intraoperatív szövódmények hatása a posztoperatív hasúri adhesiók kialakulására laparoszkópos cholecystectomiát követóen: összehasonlító állatkísérlet.

BACKGROUND: The aim of this study was to evaluate the extent of postoperative formation of adhesions following laparoscopic and open cholecystectomy. MATERIAL AND METHODS: 60 experimental laparoscopic cholecystectomies (LC) were performed in dogs by qualified surgeons to learn laparoscopic technique. To assess the relationship between complications occurred during the operation (bleeding, laceration of the liver bed or gallbladder perforation) and the formation of adhesions surviving animals were divided into 4 groups according to the type of complication. We assessed the results during second-look laparoscopy 4 weeks following LC using the adhesion index (AI: 0-4 score). Animals were then sacrificed to measure the extent of adhesions. As a control group open cholecystectomy was performed in 15 dogs without intraoperative complications. Mann-Whitney Rank Sum test and Dunn's Method were used for statistical analysis. RESULTS: No adhesions were observed in the laparoscopic group without intraoperative complications. In all dogs with bleeding or laceration of the liver bed maintained by electrocoagulation, adhesions developed. Formation of adhesion in these groups was significantly higher than in "ideal LC" or in case of gallbladder perforation (P < 0.01). All animals in the control group developed significantly more adhesions compared to the experimental group (p < 0.05). CONCLUSION: LC produces less adhesion compared to conventional open technique. Complications such as bleeding or laceration of the liver bed during LC can increase the formation of adhesions. No formation of adhesions can be related to gallbladder perforation during LC.