Experimental surgery as part of the development of degradable biomaterials for cardiovascular surgery

Introduction: Cardiovascular diseases are responsible for significant morbidity and mortality in the population. Artificial vascular grafts are often essential for surgical procedures in radical or palliative treatment. Many new biodegradable materials are currently under development. Preclinical testing of each new material is imperative, both in vitro and in vivo, and therefore animal experiments are still a necessary part of the testing process before any clinical use. The aim of this paper is to present the options of using various experimental animal models in the field of cardiovascular surgery including their extrapolation to clinical medicine. Methods: The authors present their general experience in the field of experimental surgery. They discuss the selection process of an optimal experimental animal model to test foreign materials for cardiovascular surgery and of an optimal region for implantation. Results: The authors present rat, rabbit and porcine models as optimal experimental animals for material hemocompatibility and degradability testing. Intraperitoneal implantation in the rat is a simple and feasible procedure, as well as aortic banding in the rabbit or pig. The carotid arteries can also be used, as well. Porcine pulmonary artery banding is slightly more difficult with potential complications. The banded vessels, explanted after a defined time period, are suitable for further mechanical testing using biomechanical analyses, for example, the inflation-extension test. Conclusion: An in vivo experiment cannot be avoided in the last phases of preclinical research of new materials. However, we try to strictly observe the 3R concept ­ Replacement, Reduction and Refinement; in line with this concept, the potential of each animal should be used as much as possible to reduce the number of animals.

Rare causes of acute appendicitis.

INTRODUCTION: A clinical diagnosis of acute appendicitis does not necessarily imply only inflammatory changes found upon histopathological examination. Even though appendiceal tumors are very rare, accounting for less than 4% of all gastrointestinal tumors‚ they need to be taken into account and require the right choices regarding subsequent onco-surgical management. METHODS: 1036 appendectomies were performed and 38 (3.7%) rare appendiceal tumor cases were identified at the department of Surgery in Pilsen from 1 January 2008 to 1 October 2018. The following text presents the difficult nature of the initial diagnosis, current therapy and principles of follow-up care in this relatively rare group of patients. CONCLUSION: Appendiceal tumors are very rare. Depending on the histopathological type of tumor, it is necessary to choose adequate therapy and also provide proper follow up care.

[The effect of anticoagulation and anti-aggregation treatment on the extent, development and prognosis of acute craniocerebral injury]. / Vliv antikoagulacní a antiagregacní terapie na rozsah, vývoj a prognózu akutního kraniocerebrálního poranení

PURPOSE OF THE STUDY: A retrospective analysis of the effect of anticoagulation and anti-aggregation treatments on the post-injury clinical status, frequency of necessary surgical interventions including re-operations, course of intracranial haemorrhage dynamics and treatment outcome in patients with acute traumatic intracranial haematoma. MATERIAL AND METHODS: The group consisted of 328 patients with acute post-traumatic intracranial haemorrhage treated at the author's institution from 2008 to 2012. Fifteen patients with anticoagulation therapy (warfarin; 8 females, 7 males; median age, 72.0 years) and 46 patients with anti-aggregation treatment (21 females, 25 males; median age, 75.5 years ; 37 with acetylsalicylic acid, 5 with thienopyridines, 2 with new antithrombotics and 2 taking dual anti-aggregation therapy), all older than 55 years, were included in statistical analysis. The post-injury clinical condition (Glasgow Coma Scale), incidence of haemorrhagic contusions, intracranial haematoma progression, particularly when surgery was indicated, incidence of re-operations and treatment outcome (Glasgow Outcome Scale - GOS) were the study parameters. The control group included 77 patients with post-traumatic intracranial haematoma with normal coagulation who were older than 55 years (27 females, 50 males; median age, 67 years). Patients younger than 55 years and those with normal coagulation were not included in the statistical analysis. The treatment of all patients with anti-aggregation or anticoagulation therapy was consulted with the haematology specialist. RESULTS: The median age and initial status evaluated by the Glasgow Coma Scale were similar in the groups of anti-aggregated and anticoagulated patients and the control group. The number of good treatment outcomes, as evaluated by the GOS, was significantly higher in the anti-aggregated patients than in those on warfarin. A comparison of anti-aggregated, anticoagulated and normal coagulation patients did not show any statistically significant differences in the incidence of patients operated on, in the incidence of haemorrhagic contusions requiring surgery as a marker of the severity of brain parenchyma injury, intracranial haemorrhage progression with time, particularly when requiring surgery, and the rate of re-operations. However, when comparing the group of anti-aggregated patients with the control group, the higher incidence of haemorrhagic contusions and the lower number of patients requiring surgery were found to be close to the level of statistical significance. DISCUSSION: The positive effect of anti-aggregation and anticoagulation treatment on the morbidity and mortality from cardiovascular diseases should be regarded in relation to a higher risk of haemorrhagic complications. If a bleeding complication occurs, the possibility of neutralising this treatment should be considered, but this is particularly difficult in new agents. The relationship between anti-aggregation or anticoagulation treatment and the treatment results in the patients with head injury is particularly important from the neurosurgical point of view, because the relevant literature data are ambiguous. CONCLUSIONS: The results did not confirm any statistically significant adverse effects of anticoagulation or anti-aggregation treatment on the severity of post-injury status and risk of intracranial bleeding progression. The incidence of poor outcomes is higher in anticoagulated patients than in anti-aggregated patients. Although not reaching the level of statistical significance, the results also indicate higher risk of significant haemorrhagic brain contusions in anti-aggregated patients.

[Antiaggregation and anticoagulation therapy in patients operated on for chronic subdural haematoma as related to pre-surgical status and surgical outcome]. / Vztah antikoagulacní a antigregacní terapie u nemocných s chronickým subdurálním hematomem k závaznosti predoperacního stavu a výsledku chirurgické lécby.

INTRODUCTION: Chronic subdural haematoma is a potentially threatening disease, affecting mainly advanced age patients often with frequent serious complicating diseases and extensive concomitant medication including antiaggregation and anticoagulation treatment. Surgery is indicated in symptomatic patients, with haematoma evacuation and subdural drainage via simple skull trephination in the majority of cases. The study aims to analyse the influence of presurgical anticoagulation and antiaggregation treatment on the severity of pre-surgical clinical status and final surgical outcome including the incidence of complications and haematoma recurrence. MATERIAL AND METHODS: The paper retrospectively analyses a group of 132 patients operated on from 2008 to 2013 for chronic subdural haematoma. The following parameters characterising pre-surgical clinical condition were studied: age, anticoagulation and antiaggregation treatment administered, other haemocoagulation problems, interval between the probable injury and surgery, duration of symptoms, the patients pre-surgical clinical condition (Glasgow Coma Scale) and the presence of a speech disorder or at least moderate limb paresis. In the postoperative period and subsequent follow- up, the type of surgery, haematoma recurrence, reoperation technique, postoperative complications and final outcome (Glasgow Outcome Scale) were analysed. RESULTS: 64 patients (42 males, 22 females) without antiaggregation and anticoagulation treatment or other medication potentially altering haemocoagulation with normal coagulation parameters (control group), 20 patients (13 males, 7 females) on anticoagulation and 37 patients (30 males, 7 females) on antiaggregation met study inclusion criteria. Anticoagulated patients and patients on antiaggregation were significantly older than the control group patients. Statistical analysis also proved a shorter duration of clinical symptoms and worse clinical condition (GCS) in anticoagulated patients than in the control group. Skull trephination with drainage was the primary surgery indicated in all but one patient, in patients with anticoagulation or antiaggregation after adequate haematological treatment. Although the incidence of reoperation due to haematoma recurrence and postoperative complications was the highest in anticoagulated patients, this difference from the control group did not reach the level of statistical significance. The analysis of clinical outcome (>2 months after surgery) shows a similar proportion of patients with good outcome (Glasgow Outcome Scale 4.5) in all studied groups - control group 82.8%, anticoagulation treatment 80%, antiaggregation treatment 83.8%. CONCLUSION: Study results did not confirm statistically a significant negative effect of antiaggregation or anticoagulation treatment after adequate pre-surgical preparation on surgical outcomes in chronic subdural haematoma patients (Glasgow Outcome Scale). The highest incidence of complications and haematoma recurrencies was found in anticoagulated patients, although the difference does not reach the level of statistical significance.

Subthalamic electrode implantation using the MicroDrive system and the importance of microrecording data.

OBJECTIVE: The aim of the paper was to describe the relationship of the anatomical and electrophysiological target for the subthalamic electrode implantation in Parkinson's disease patients defined as the best electrophysiological recordings from multiple paralel electrodes tracts with a target discrepancy explanation. BACKGROUND: Although microrecording is the standard in subthalamic stimulation, microelectrode monitoring prolongs surgical time and may increase the risk of haemorrhagic complications. The main purpose for the electrophysiological mapping is to overcome the discrepancy between the anatomical and electrophysiological targets. METHODS: Subthalamic electrodes were stereotactically implanted in 58 patients using microrecording by means of parallel electrodes at defined distances. The relationship of the final electrode to the anatomical trajectory, the subthalamic nucleus electrical activity length, and the relationship of right and left electrodes were analysed. RESULTS: The final electrode placement matched the anatomical trajectory in 53.4 % of patients on the right side, and 43.1 % of patients on the left side. The electrode position was symmetrical in 38.3 % of patients. The analysis of left and right electrode positions did not prove brain shift as the sole factor responsible for anatomy-functional discrepancy. Further, neither age, Parkinson's disease duration, or L-DOPA adverse effects were confirmed as responsible factors. CONCLUSIONS: The difference between the anatomical trajectory and the final electrode placement underlined the need for functional microelectrode monitoring. Brain shift is not the only causative factor for the difference (Tab. 7, Ref. 27).

[The effect of age, alcohol intoxication and type of brain injury on the prognosis of patients operated on for craniocerebral trauma]. / Vliv veku, alkoholové intoxikace a charakteru poranení mozku na prognózu operovaných zranených s kraniocerebrálním poranením.

INTRODUCTION: Advanced age is reported to be an important negative prognostic factor for the final functional outcome in patients after craniocerebral injury. Worse prognosis can also be expected in the presence of significant brain contusion, requiring surgical treatment because of expansive behaviour. Definite adverse influence of alcohol intoxication at the time of injury has not been proven by current literature data. The aim of the study is to analyse the importance of the above mentioned factors for the treatment outcome in patients operated on for craniocerebral injury. MATERIAL AND METHODS: In the group of 246 patients with craniocerebral injury operated on between 2007 and 2011, the authors focused on the influence of age (145 patients < 60 years, 101 patients > 60 years), alcohol intoxication at the moment of injury (blood alcohol level over 0.1% based mainly on serum osmolarity plus clinical signs of alcohol intoxication) and the presence of brain contusion requiring surgical decompression on the final clinical outcome (using the Glasgow Outcome Scale). RESULTS: 54.1% of patients under 60 years of age were alcohol-intoxicated at the moment of injury. The incidence of alcohol intoxication in patients older than 60 years was 35.7%. The incidence of expansive brain contusions requiring surgical decompression was higher in patients older than 60 years and patients with alcohol intoxication. Statistical analysis of prognosis as related to age has shown significantly worse prognosis in patients older than 60 years. The difference was also significant in the subgroup of non-intoxicated patients. Statistical analysis did not show worse prognosis in alcohol-intoxicated patients. The presence of significant contusions influenced the injury prognosis only in patients younger than 60 years. CONCLUSION: The impact of age on the final treatment outcome in patients with craniocerebral injury was proven. The study did not show significant deleterious effect of alcohol intoxication at the time of injury on the final outcome.

[Pharmacoresistant epilepsy after craniocerebral injury]. / Farmakorezistentní epilepsie po kraniocerebrálním poranení.

INTRODUCTION: Posttraumatic epilepsy is one of the possible serious consequencies of both closed and open head injury with clinical manifestation months or years after surgery. In pharmacoresistant patients, surgical therapy should be considered. MATERIAL AND METHODS: The study summarises the results of surgical treatment of pharmacoresistant posttraumatic epilepsy in a group of 13 patients (11 males and 2 females). Average age at the time of injury was 9.6 years in males and 8.8 years in females. The average number of seizures was 10.7-17 seizures/month preoperatively. Invasive EEG monitoring was required in 5 patients in whom non invasive or semiinvasive investigations failed to localize the epileptogenic zone adequately. Temporal lobe resections were performed in 4 patients, 4 patients underwent extratemporal resections and vagus nerve stimulation system was implanted in 5 patients. RESULTS: Three patients (75%) after temporal resections became seizure free (Engel I) and in the remaining patient significant reduction of seizures was achieved (Engel III). There were 2 seizure free patients after extratemporal resections (50%) and significant reduction of seizure rates was achieved (Engel III) in the remaining two. One patient after vagus nerve stimulation met the criteria for > 90% response and there was a 50-90% seizure rate reduction in the remaining 4 patients (vagus nerve stimulation responder). CONCLUSIONS: Although in limited group of patients the study confirms good results of surgical treatment of selected posttraumatic epilepsy patients--mainly temporal epilepsy patients and patients after vagus nerve stimulation. Meticulous presurgical evaluation including invasive encephalography in indicated patients is a precondition for surgical success.

[Neuroendoscopic biopsy of a brain tumor]. / Neuroendoskopická biopsie tumoru mozku.

BACKGROUNDS: Neuroendoscopic biopsy is one of the techniques that can be used for histological verification of a suspected brain tumor. The use of neuroendoscopy is particularly useful for cystic tumors and para- and intraventricular brain tumors that are risky for stereotactic biopsy. The technique of navigated neuroendoscopy enables biopsy sampling under visual control, haemostasis of biopsy site and treatment of cerebrospinal fluid pathways obstruction. PATIENTS AND METHODS: Neuroendoscopic technique was used for biopsy in one patient with a solid brain tumor. 23 patients (12 males, mean age 49.7 years, range 21-75 years and 11 females, mean age 59.1 years, range 22-76 years) with a suspected cystic brain tumor underwent neuroendoscopic biopsy. Suspected intra- or paraventricular brain tumor presented indication for neuroendoscopic biopsy in 36 patients (20 males, mean age 43.9 years, range 6-80 years and 16 females, mean age 46.2 years, range 11-78 years). RESULTS: High grade glioma was most frequently diagnosed in patients with cystic brain tumors, followed by low grade gliomas and metastatic tumors. Diagnostic sample was obtained from all patients. Tumor resection was performed in 7 patients with a cystic tumor after neuroendoscopic biopsy and histological findings were identical in 70.1% of them. Similarly, high grade glioma was most frequently diagnosed in patients with intra or paraventricular tumors, followed by tumors originating from pineal region tissues. Diagnostic sample was obtained from 94.3% of patients. Tumor resection was performed in 5 patients after neuroendoscopic biopsy and histological findings of the resected tissue was identical with neuroendoscopic biopsy in 4 of them (80%). CONCLUSIONS: Neuroendoscopy is a safe biopsy technique for a subset of patients who are high risk for the use of stereotactic biopsy, with comparable results. Neuroendoscopy also provides for cerebrospinal fluid circulation obstruction treatment. The use of neuronavigation or stereotactic planning is particularly useful for the planning of an optimal surgical approach, helps to maintain anatomical orientation in distorted anatomy and facilitates haemostasis in case of intraoperative bleeding.

[Primary brain tumor as a rare cause of acute subdural hematoma]. / Primární tumor mozku jako vzácná prícina akutního subdurálního hematomu.

The aim of the study is to present a case report describing patient, admitted for subdural haematoma located on temporal lobe base and brain convexity with intracerebral haematoma located in the depth of temporal lobe. Both haematomas were evacuated from burr holes. Histological analysis of tissue obtained during intracerebral haematoma aspiration has proven tumorous tissue consistent with anaplastic astrocytoma. Contrast enhanced MRI has confirmed the diagnosis and patient underwent tumor surgery. The study brings additional data to differential diagnosis of subdural haematoma, especially of non traumatic origin. When compared with meningiomas and metastatic tumors primary brain glioma is an exceptional cause of subdural haematoma of non traumatic origin.

Neuroendoscopy.

The discovery of optic bulb paved the way for the development of safe endoscopic systems not only with diagnostic ability, but also suitable for treatment. At the beginning of the 20th century, the first attempts to use an endoscope in the treatment of hydrocephalus have been made with encouraging results. Although the invention of an implantable shunt system slowed down the development of neuroendoscopy, the progress in fiberoptics and image processing has established the potential for the neuroendoscopy boom. Together with microneurosurgery, neuroendoscopy has established the concept of minimally invasive neurosurgery (Fig. 4, Ref. 16). Full Text (Free, PDF) www.bmj.sk.

[Experience with radiofrequency termoablation of brain tumors]. / Zkusenosti s radiofrekvencní termoablací mozkových nádoru.

Together with tissue sampling stereotaxy in neurooncology makes also targeted intervention such as brain tumor radiofrequency thermoablation possible. In the paper authors present their experience with navigated radiofrequency thermoablation in 18 patients. Cerebral metastasis was the treated lesion in 5 patients, 8 patients were operated on for brain glioma and 3 for pituitary adenoma. In 2 patients radiofrequency thermoablation of pituitary gland was undertaken to treat malignant pain or refractory diabetes. Presurgical planning using stereotactic software was utilised in all patient. In one patient it was necessary to perform tumor debulking because the local oedema of pituitary adenoma was threatening both optic nerves. Radiofrequency thermoablation is advantageous technique in circumscribed lesions, not exceeding 3 cm diameter, deeply seated. Perilesional oedema with intracranial hypertension is surgical limitation. Good tolerance of minimally invasive surgery and the possibility of biopsy sampling before radiofrequency thermoablation is an advantageous feature. Infiltrative growth of glial neoplasm together with irregular shape is the limitation of radiofrequency thermoablation in brain gliomas.

[Meningiomas with skull bone involvement]. / Meningiomy s postizením kostních struktur lebky.

One of factors responsible for meningioma recurrencies is tumorous involvement of calvarial and basal bone structures. Primary intraosseous meningiomas should be distinguished from secondary involvement in prevailing intracranial tumor and hyperostotic reactive changes. The paper is based on prospective study of 167 patient operated on for intracranial meningioma. Based on clinical investigation, radiological and intraoperative data bone invasion was suspected in 20 patients and histologically confirmed in 17. In 14 patients bone involvement was secondary, meningothelial hamartoma was described in one patient and in 2 patient primary intraosseous meningioma was found. Prevalence of tumors to periorbital area and bone sutures is confirmed. Neuronavigation is used to optimise tumor resection and limit the risk for neurovascular structures. Results were good in 87.5% of patients and poor in 12.5% of patients (extent of tumor and general condition). Discussion provides analysis of intraosseous meningiomas formation, pathological classification (Lang), causes of bone invasion and surgical possibilities. It is necessary to undeline the problems of intraosseous meningiomas both from the aspects of diagnosis and subsequent treatment.

Neuroendoscopic management of haematocephalus.

The purpose of the paper was to publish the results of endoscopic treatment of primary and secondary haematocephalus in the group of 23 patients, treated by means of Wolf endoscopic system combined with frame based navigation with the aid of virtual reality environment. The procedure is aimed to remove blood clots from the cerebral ventricles and to reduce the volume of parenchymal haematoma in secondary haematocephalus during single surgical session. In the majority of the treated patients septostomy was added to make revision of both lateral ventricles possible from a single approach, and the operation was completed with endoscopic third ventriculostomy to reduce the amount of blood in the basal cisterns and to reestablish the patency of cerebrospinal fluid pathways, so that lumbar puncture can be safely done to facilitate the process of cleaning blood away from the cerebrospinal fluid. The surgery always facilitates the resorption of residual blood as well as blood degradation products, therefore late complications, such as posthaemorrhagic hydrocephalus, membranes and stenosis formation was prevented. Improvement of the clinical condition was obtained without the need for permanent drainage systems insertion. Lethal outcome in one patient and unfavourable clinical result in another three patients were unrelated to the endoscopic treatment. (Tab. 1, Fig. 2, Ref: 10.)

Detection of mouse cells producing antibodies against the azophenylarsonic group by haemolytic plaque assay.

For detection of mouse cells producing anti-ARS antibody a modified method using ARS-SRBC is described. For optimal results a suitable source of SRBC must be selected. The number of ARS groups per SRBC required for optimal lysis in PFC assay varies, and ARS-SRBC prepared by the method of Ingraham which are suitable for detection of rabbit-PFC give negative results with the mouse system. ARS-SRBC prepared for the PFC assay are unsuitable for the haemagglutination test and vice versa.

Immunostimulatory effect of cis-diamine dichloroplatinum (II).

Cis-diamine dichloroplatinum (II) (DDP) injected i.p. or i.v. at the dosage of 0.83 mg/kg to BALB/c mice on days 0, 7 and 14 elicited antibodies against proteins (RSA, BGG) and haptens (TNP, FITC) detectable by ELISA or by passive haemagglutination. Significant increase in antibody production was observed with either route of DDP application. A similar set of antibodies against antigens which do not cross-react with the immunizing proteins was observed when mice were immunized with complexes formed by an in vitro incubation of RSA and BGG with DDP. Thus, proteins modified in vivo or in vitro by DDP may stimulate the production of antibodies of unexpected specificities.

IL-2 and IL-3 production in high and low IgG-responding strains of mice.

The antibody response of mouse strain C57Bl/10ScSn (B10) is characterized by a low IgG responsiveness to a number of different antigens. Aberrant function of antigen-presenting cells and/or low activity of the Th cell population have been suggested as the cause of the defect. We studied the production of IL-2 and IL-3 in vitro by unstimulated and ConA-stimulated spleen cells. Unstimulated spleen cells of low-responding B10 mice produce significantly less IL-2 compared with the high-responding A/J mice in both intervals tested, i.e. after 24 and 48 h of in vitro incubation. IL-3 production is low but almost comparable in unstimulated cells of both strains. Stimulation of spleen cells by 5 micrograms/ml of ConA leads to considerably higher production of IL-2 in A/J spleen cells. IL-3 production by ConA-stimulated spleen cells showed the same pattern of activity. This low IL-3 production by B10 cells is most likely due to the low production of IL-2 during Th cell activation and to the limited proliferation of these cells. The low IgG production of B10 spleen cells during the secondary response to SRBC in vitro could be restored by IL-2 added to the medium. 50 U/ml of IL-2 increased the number of anti-SRBC IgG-producing cells 40 times in B10 cells, but only 4 times in A/J cells, so that the IgG production in B10 cells reached the same level as that in the A/J cells without exogenous IL-2. We suppose that the limited IL-2 production in the low-responding strain B10 is the cause of the low IgG responsiveness of these mice.

Immunological problems of polymer-bound drugs.

For the application of polymer-bound drugs (especially in combination with the targeting antibodies), it is essential to know more about the immunogenicity and possible hazards from immune reactions induced by their repeated application. The immune reaction depends on many factors (including structure of antigen, dose of antigen, schedule and way of the application, genetic background of the immunized, i.e., receiving organism) and could be weakened or eliminated by a choice of suitable factors. Problems connected with the immune reaction of the humoral and cellular type (B and T cell involvement) against different polymers and polymer-bound drugs and possible consequences for their clinical use will be discussed.

Omental dendritic cells: Ia expression and relation to macrophages.

Rat omental dendritic cells (ODC) occur in two forms, mainly spindle-shaped, Ia-, on the surface, and stellar, Ia+ within the omentum. Like macrophages, most ODC label with W3/25 mAb and have a demonstrable activity of non-specific esterase, acid phosphatase and ATPase. Up to 30% of ODC are actively phagocytic. The proportion of Ia+ ODC rises 7 days after ip antigenic stimulation and there seems to be a reciprocal development of Ia positivity and phagocytic capacity between ODC and macrophages 3 and 5 days after ip immunization. ODC contribute to the overall fluctuation of Ia expression in the entire omentum after immunization. Ia+ ODC display a linear arrangement along preilymphatic spaces and may be related to the formation of new lymph vessels. They also constitute the stroma of pseudofollicles containing clusters of what are presumably T-helper lymphocytes closely attached to ODC, scattered suppressor T lymphocytes and B cells accumulating in later stages at the immune response.

Experimental ablation nephropathy. Fine structure, morphometry, cell membrane epitopes, glomerular polyanion and effect of subsequent transplantation.

The subtotal (5/6) nephrectomy performed in 23 adult female rats induced severe hypertrophy of residual parenchyma with interstitial fibrosis, tubular dilatation, and focal and segmental glomerulosclerosis (FSG). This ablation nephropathy (AbN) caused proteinuria, progressive renal failure, and hypertension. The extent of FSG was assessed by semiquantitative scoring. The ultrastructure revealed widespread foot process fusion, many dense cytoplasmic inclusions in podocytes, and degenerative changes or disruption of mesangium with glomerular "microcysts". Numerous granular deposits of rat Ig were seen in the glomeruli but a short praeterminal i.v. load by heat-aggregated human Ig did not alter the morphology of AbN and produced discrete and inconstant glomerular deposits. Similarly an i.v. injection of protamine and heparin generated protamine-heparin complexes seen in various layers of glomerular capillary wall, similar to those found previously in normal rats. AbN displayed a partial irregular depletion of polyanion sites reactive with polyethylenimine in lamina rara externa. A significant increase in both glomerular and interstitial Ia+ cells and a marked predominance of W3/25+ cells in the interstitial infiltrates were documented by immunohistochemistry in the remnant kidneys. Both AbN and FSG could be largely corrected (or prevented?) by subsequent syngeneic renal transplantation (TPL; 6 animals). On the other hand a severe AbN was found in two post-ablation residues after unsuccessful TPL with graft necrosis or sclerosis.--AbN has some analogies to various chronic human nephropathies (e.g. FSG) and may explain their progression to the terminal failure. Degenerative and finally destructive mesangial lesion seems to be of prime importance in AbN.

Protein aggregates in extracorporally perfused rabbit kidneys.

Eighteen rabbit kidneys were perfused ex vivo for 1 h with allogeneic blood, and in 16 a solution of xenogeneic aggregate-free, aggregated or antibody-complexed protein was added to the perfusate 5 min after the start (human immunoglobulins or serum albumin, partly cationized, were used). The kidneys were examined by light and electron microscopy and the human and rabbit immunoglobulin (or albumin) precipitates were detected by direct immunofluorescence and ultrastructural immunohistochemistry. In 13 kidneys the perfusion produced small segmental glomerular endocapillary aggregates of platelets, leukocytes, and granular precipitates reactive with both anti-rabbit and anti-human antibodies. No typical deposits were seen in mesangium or in periphery of glomerular capillaries but rabbit Ig penetrated to the inter- and subepithelial spaces of proximal convoluted tubules. Three kidneys perfused by cationized aggregated human Ig (or by cationized albumin-antialbumin complexes) exhibited a destructive lesion with rapid breakdown of blood flow and massive global endocapillary plugs of similar ultrastructure but with focal endothelial sloughing. Pericapillary granular precipitates of human and rabbit Ig were seen in these kidneys. When the blood with cationized Ig aggregates was used for perfusion of two further kidneys extensive endocapillary aggregates with endothelial damage reappeared but the extracapillary penetration and precipitation were lacking and the blood flow largely improved. Membrane polyanion of podocytes stained by colloidal iron was preserved even in close proximity of cationized complex precipitates. Thus, in the ex-vivo perfusion model the preformed neutral aggregates did not penetrate through the glomerular capillary wall and were not phagocytized by mesangial cells. The cationized aggregates induced rapid circulatory failure with massive platelet clumping and granular pericapillary "humps" ultrastructurally different from the deposits of human and experimental immune complex glomerulonephritis.