Search

Background: The aim of our study was to assess the impact of different thawing protocols on morphological changes arising in cryopreserved human saphenous vein grafts., Methods: The study was performed in 12 saphenous vein grafts harvested in brain death donors. Storage in the vapor phase of liquid nitrogen for 3 or 5 years followed. Two thawing protocols were tested: slow thawing in a refrigerator at temperature +4°C for 2 hr and rapid thawing-in a water bath at +37°C. Grafts were processed for scanning electron microscopy. Comparisons of continuous parameters under study between experimental groups were performed using the t-test (age, cold ischemia time, exposure to cryoprotectant, time of storage, total thawing time, mean thawing rate, morphology scoring of thawed HSVG) and the median test (HSVG length). Categorical parameters (sex and blood group) were formally tested using the chi-square test., Results: All samples were evaluated according to morphological changes and scored in terms of morphologically intact endothelium, confluent endothelium with structural inhomogeneity, disruption of the intercellular contacts, separation of the endothelial cells, complete loss of the endothelium, and damage of the subendothelial layers. There is no statistically significant difference between the sample sets at the significance level of 0.05. There was no association with donors' age, sex, and time of storage., Conclusions: Human cryopreserved saphenous vein grafts in our experimental work showed no difference in terms of structural deterioration of the endothelial surface and basal membrane depending on different thawing protocols used., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: The aim of our experimental work was to assess the impact and morphological changes that arise during different thawing protocols on human aortic valve (AV) leaflets resected from cryopreserved aortic root allografts (CARAs)., Objectives: Two thawing protocols were tested: 1. CARAs were thawed at a room temperature (23°C); 2. CARAs were placed directly into a water bath at a temperature of 37°C. After all the samples were thawed, non-coronary AV leaflets were sampled from each specimen and fixed in a 4% formaldehyde solution before they were sent for morphological analysis., Material and Methods: All the samples were washed in distilled water for 5 min and dehydrated in a graded ethanol series (70%, 85%, 95%, and 100%) for 5 min at each level. The tissue samples were then immersed in 100% hexamethyldisilazane (HMDS) for 10 min, and then air-dried in an exhaust hood at room temperature. Processed samples were mounted on stainless steel stubs and coated with gold. Histological analysis was performed with the use of an electron microscope on a scanning mode operating at 25 kV - BS 301., Results: Thawing protocol 1 (room temperature at 23°C): 6 (100%) samples showed loss of the endothelial covering of the basal membrane with no damage to the basal lamina. Thawing protocol 2 (water bath at 37°C): 5 (83%) samples showed loss of the endothelial covering of the basal membrane with no damage to the basal lamina. One (17%) sample showed loss of the endothelial covering the basal membrane with significant damage to the basal membrane., Conclusions: Based on our experimental work, we can clearly conclude that cryopreserved AV leaflet allografts show identical structural changes at different rates of thawing.

Background: The aim of our experimental work was to assess morphological changes of arterial wall that arise during different thawing protocols of a cryopreserved human aortic root allograft (CHARA) arterial wall., Methods: The experiment was performed on CHARAs. Two thawing protocols were tested: 1, CHARAs were thawed at a room temperature at +23°C; 2, CHARAs were placed directly into a water bath at +37°C., Microscopic Samples Preparation: After fixation, all samples were washed in distilled water for 5 min, and dehydrated in a graded ethanol series (70, 85, 95, and 100%) for 5 min at each level. The tissue samples were then immersed in 100% hexamethyldisilazane for 10 minutes and air dried in an exhaust hood at room temperature. Processed samples were mounted on stainless steel stubs, coated with gold., Results: Thawing protocol 1: All 6 (100%) samples showed loss of the endothelium and damage to the subendothelial layers with randomly dispersed circular defects and micro-fractures without smooth muscle cells contractions in the tunica media. Thawing protocol 2: All 6 (100%) samples showed loss of endothelium from the luminal surface, longitudinal corrugations in the direction of blood flow caused by smooth muscle cells contractions in the tunica media with frequent fractures in the subendothelial layer., Conclusion: All the samples thawed at the room temperature showed smaller structural damage to the CHARA arterial wall with no smooth muscle cell contraction in tunica media when compared to the samples thawed in a water bath.

Purpose of the Study: To identify some characteristics of bone repair capacity in elderly patients who undergo total hip arthroplasty, which requires good healing ability of bone for implant osteointegration and bone defect repair, particularly if revision arthroplasty is necessary., Material and Methods: In a group of 27 patients (mean age, 70 ± 7 years; range, 60 to 81 years) a coincidence of osteoarthritis and osteopenia/ osteoporosis was assessed, and mesenchymal stem cells (MSC) were isolated and their numbers, viability and proliferative capacity were evaluated. The MSC populations were examined for their behaviour on bone tissue scaffolds used in orthopaedic surgery for treatment of bone lesions. Each patient underwent bone densitometry examination before total hip arthroplasty. Bone marrow was harvested intra-operatively from the trochanteric region of the femur. From a portion of bone marrow, MSCs were isolated and cultured, and a mononuclear cell concentrate was obtained. Either whole bone marrow or a mononuclear cell concentrate was applied to selected matrices (allograft, demineralised bone matrix, porous beta-tricalcium phosphate (-TCP), pressed hydroxyapatite or calcium sulphate). The production of new collagen and extracellular mineralized matrix were first assessed in expansion medium and, when the production was low, differentiation medium was used., Results: A coincidence of osteoarthritis and osteopenia/osteoporosis was found in 50% of the patients. All were women with a low body mass index and had been post-menopausal for an average of 23 years. The isolated MSCs contained a high percentage of viable cells (mean, 95%). The mesenchymal cells of patients with osteopenia, as compared with those having normal bone density, showed markedly lower numbers of fibroblastic colony forming units (CFU-F) per ml and had a lower proliferative capacity because the population doubling time during the first four passages was much longer. Of the scaffolds tested, allografts showed the most marked collagen and extracellular mineralized matrix production in expansion medium with either whole bone marrow or a monocyte concentrate; porous -TCP was the best of bone graft substitutes in collagen and extracellular mineralized matrix production by both whole bone marrow and a monocyte concentrate, but this was only in differential medium., Discussion: The coincidence of ostearthritis with osteopenia/osteoporosis was found in a higher number of our patients than is reported in the literature. Also, a lower MSC proliferative capacity and a low number of CFU-F/ml in the patients with low bone density were interesting findings. Better bone regeneration would generally be achieved with higher MSC numbers and the use of growth factors for stimulation of osteoinduction and angiogenesis. Bone marrow harvesting for MSC isolation, cultivation and subsequent transplantation is currently feasible only in an experiment. A bone marrow aspirate can be applied, but it may not provide a sufficient number of MSCs. In addition to autologous bone grafts, the best collagen production was on allografts. In bone graft substitutes, the porous structure played an important role because on a non-porous material (calcium sulphate) the formation of collagen was very low. There was no difference in collagen and extracellular mineralized matrix production between whole bone marrow and monocyte concentrates., Conclusions: Elderly patients have reduced bone healing capacity also because of osteopenia/osteoporosis that occurs more often than it is generally diagnosed, including its coincidence with osteoarthritis. The mesenchymal stem cells isolated from osteopenic bone give a lower number of CFU-F/ml and have a lower proliferative capacity. Of the matrices for new bone formation, allografts showed the best results because collagen was produced already in expansion medium. Of the graft substitutes, porous -TCP was the best, but with collagen production in differential medium. The use of bone marrow aspirate is currently a method of choice in order to increase MSC numbers at the site of bone healing. The use of growth factors is an expensive treatment. To achieve the goal of reliable promotion of osteogenesis with cultured MSC transplantation and use of composite materials with pro-osteogenic and pro-angiogenic factors will still require many experimental and clinical studies.

A rat model of early sepsis induced by lipopolysaccharide (LPS) combined with interleukin-2 (IL-2) was developed. The primary aim was to assess the pharmacokinetics of gentamicin and sepsis-induced pathophysiological changes. Moreover, the effects on the glomerular filtration rate and tubular function were studied in septic and control rats. First, an intravenous (i.v.) bolus of LPSIL-2 (1 mg/kg-Pseudomonas aeruginosa, 15 µg/kg IL-2) or saline (controls, C) was administred. The Wistar rats were treated 30 min after LPSIL-2 with gentamicin as a 3 mg/kg i.v. bolus followed 10 min later by an i.v. 170-min infusion (GE, 0.09 mg/kg·min(-1)). The monitoring of vital functions, biochemistry and GE concentrations was performed. Creatinine clearance was 2-3 times lower and fractional urea excretion was 3-4 times less in septic rats as compared to controls(p<0.05), although urine flow was comparable. Capillary leakage caused a 55% elevation in the volume of distribution (V(c)) in the LPSIL+GE group vs. C+GE (p<0.05). The renal CL(ge) was less (2.2±0.59 vs. 3.8±0.53 mL/min·kg(-1), p<0.05), while the total CL(ge) was comparable (5.9±1.5 vs. 6.7±1.1 mL/min·kg(-1); p=0.30). In the LPSIL+GE group relative to C+GE, the half-life (t(1/2)) was 79% higher (p<0.05) and GE concentrations detected at the end of the study in the plasma and kidney were elevated 2.5-fold (p=0.09) and 2.2-fold (p<0.05), respectively. The model reproduced several consequences of early sepsis like in patients such as capillary leak, a decreased glomerular filtration rate (GFR) and the changes in pharmacokinetics of GE (increased values of V(c) and t(1/2) and a drop in renal CL(ge) proportional to that of CL(cr)). Nonrenal routes which, for the most part, compensate the reduced renal CL(ge) in septic rats deserve further study.

Reactivation effects of K203 and currently available oximes (obidoxime, HI-6) in combination with atropine on acetylcholinesterase activities in the brain parts of rats poisoned with tabun were studied. The activity was determined by quantitative histochemical and biochemical methods correlating between them very well. The tabun-induced changes in acetylcholinsterase activity as well as in reactivation potency of reactivators used were different in various parts of the brain. Pontomedullar area seems to be important for observed changes following tabun intoxication and its treatment. From the oximes studied, the reactivation effect of K203 was comparable with obidoxime; HI-6 was ineffective. Combination of bio- and histochemical methods allow fine differentiation among the action of different oximes following tabun poisoning.

Tabun belongs to the most toxic nerve agents. Its mechanism of action is based on acetylcholinesterase (AChE) inhibition at the peripheral and central nervous systems. Therapeutic countermeasures comprise administration of atropine with cholinesterase reactivators able to reactivate the inhibited enzyme. Reactivation of AChE is determined mostly biochemically without specification of different brain structures. Histochemical determination allows a fine search for different structures but is performed mostly without quantitative evaluation. In rats intoxicated with tabun and treated with a combination of atropine and HI-6, obidoxime, or new oxime K048, AChE activities in different brain structures were determined using biochemical and quantitative histochemical methods. Inhibition of AChE following untreated tabun intoxication was different in the various brain structures, having the highest degree in the frontal cortex and reticular formation and lowest in the basal ganglia and substantia nigra. Treatment resulted in an increase of AChE activity detected by both methods. The highest increase was observed in the frontal cortex. This reactivation was increased in the order HI-6 < K048 < obidoxime; however, this order was not uniform for all brain parts studied. A correlation between AChE activity detected by histochemical and biochemical methods was demonstrated. The results suggest that for the mechanism of action of the nerve agent tabun, reactivation in various parts of the brain is not of the same physiological importance. AChE activity in the pontomedullar area and frontal cortex seems to be the most important for the therapeutic effect of the reactivators. HI-6 was not a good reactivator for the treatment of tabun intoxication.

The aim of our study was to evaluate differences between males and females based on patterns of costal cartilage ossification and also with respect to ageing. We provided diagnosis of ossifications from two files of radiograms. The first group consisted of 1044 chest and abdominal radiograms of patients (537 men and 507 women), ranging in age from 10 to 95 years obtained by using conventional X-ray technique. The second group was a set of 55 radiograms of chest plate fragments of cadavers (29 men and 26 women) aged from 15 to 98, obtained by using soft X-ray imaging in the skiagraphic-skiascopic unit. Ossifications were identified in more than 80% of the cases. They appear in puberta and their occurrence increases with age. The peripheral ossification pattern, typically the male pattern, is characterized by subperichondral deposits which contour the upper and lower margin of cartilage. The female, central lingual ossification pattern, is characterized by the pyramidal (lingual) shape of ossifications with a peak towards the sternum. The existence of another typical female central globular model of ossification was not confirmed in the file of cadavers. Central globular foci were found in both sexes (62% of women and 34% of men) from the 3rd decade. In the sample of Caucasian men and women (Czech population) we detected a frequent occurrence of costal cartilage ossification. Peripheral and central lingual patterns are highly predictive for sex determination. Globular loci of ossifications can be used for age estimation.

Differences between acetylcholinesterase (AChE) inhibition in the brain structures following VX and RVX exposure are not known as well as information on the possible correlation of biochemical and histochemical methods detecting AChE activity. Therefore, inhibition of AChE in different brain parts detected by histochemical and biochemical techniques was compared in rats intoxicated with VX and RVX. AChE activities in defined brain regions 30 min after treating rats with VX and Russian VX intramuscularly (1.0 x LD(50)) were determined by using biochemical and histochemical methods. AChE inhibition was less expressed for RVX, in comparison with VX. Frontal cortex and pontomedullar areas containing ncl. reticularis has been found as the most sensitive areas for the action of VX. For RVX, these structures were determined to be frontal cortex, dorsal septum, and hippocampus, respectively. Histochemical and biochemical results were in good correlation (R(xy) = 0.8337). Determination of AChE activity in defined brain structures was a more sensitive parameter for VX or RVX exposure than the determination of AChE activity in the whole-brain homogenate. This activity represents a "mean" of the activities in different structures. Thus, AChE activity is the main parameter investigated in studies searching for target sites following nerve-agent poisoning contributing to better understanding of toxicodynamics of nerve agents.

Acetylcholinesterase activity in defined brain regions was determined using biochemical and histochemical methods 30 min after treating rats with sarin, soman or VX (0.5 x LD(50)). Enzyme inhibition was high in the pontomedullar area and frontal cortex, but was low in the basal ganglia. Histochemical and biochemical results correlated well. Determination of the activity in defined brain structures was a more sensitive parameter than determination in whole brain homogenate where the activity was a "mean" of the activities in different structures. The pontomedullar area controls respiration, so that the special sensitivity of acetylcholinesterase to inhibition by nerve agents in this area is important for understanding the mechanism of death caused by nerve agents. Thus, acetylcholinesterase activity is the main parameter investigated in studies searching for target sites following nerve agent poisoning.

The use of allografts represents one of the therapeutic options in the treatment of vascular prosthetic infection. Close cooperation with a transplant center is unconditional for successful graft harvest and storage. Although the transplantation programme in the Czech Republic is handled in several centers across the country the use of vascular allografts is still exceptional. During multiorgan harvest procedures arterial or venous grafts have been removed and stored in antibiotic solution at 4 degrees C till implantation. Cardioplegic and short-term organ preserving solution Custodiol was used in our cohort. At the Department of Vascular Surgery of the Na Homolce Hospital in Prague fresh arterial allografts were used in 14 patients in the years 2001-2004. In all, absence of usable autologous graft was the common denominator. In ten cases previous synthetic vascular grafts were infected. Of these, critical limb ischaemia and imminent amputation due to the poor outflow tract occurred in three patients. Once, false femoral artery aneurysm infected with methicilin-resistant Staphylococcus aureus (MRSA) led to several hemorrhagic episodes. There was no early mortality but one early occlusion with subsequent major amputation. In 11 patients (79%) the procedure was uneventful at the short-term follow-up. All patients were treated with cyclosporine.

The aim of this study was to compare changes in activity of acetylcholinesterase (AChE) in the brain and motor endplates of rat after administration of soman and tabun. We took brain and diaphragm from laboratory rats administered a median lethal dose (LD(50)) of soman or tabun. Enzyme activity of AChE was studied in selected structures of brain and in motor endplates in the diaphragm. Histochemical detection of AChE by Karnovski and Roots with simultaneous histochemical detection of alkaline phosphatase in case of brain sections was used. The highest activity of AChE in the control group was found in the striatum, amygdaloid nuclei, substantia nigra, superior colliculi, and motor nuclei of cranial nerves V, X a XII. LD(50) of both nerve agents dramatically decreased the activity of AChE in the structures studied--both brain and diaphragm. After intoxication by either agent, activity in above mentioned nuclei was characterized as low or focally moderate. Very low activity was seen in some structures (CA3 field of hippocampus, some nuclei of the tegmentum and cerebellar cortex). We found minimal differences in the histochemical picture of soman or tabun intoxication, apart from the striatum and the superior colliculi which showed stronger inhibition by tabun.

The gastrointestinal tract epithelium plays an important role not only in digestion and absorption of nutrients, but also in antigen and pathogen signal translocation toward the gut associated lymphoid tissue. Malnutrition in various degrees is recognized as the most common cause of the immune system dysfunction. Research done in the past several years has revealed that dietary nucleotides (dNT) represent an essential compound of nutrition because of their importance in metabolic pathways, energetic processes and nucleic acid synthesis during tissue renewal. Much evidence accumulated suggests that dNT are essential for the growth and maturation of the gut epithelia. In previous experiments we have documented immunoregulative properties of dNT-containing extracts. In this study Balb/c female mice were fed (1) standard diet, (2) dNT-supplemented diet, and (3) dNT-supplemented water for 4 weeks. The supplement in dose of 100 mg/kg/l comprised original extract (Imuregen, Uniregen Ltd., Náchod, Czech Republic). Samples of terminal ileum in each dietary group were removed for histological examination. The length of villi was evaluated by computer morphometry. The highest growth of intestinal villi was observed in group administered dNT-supplemented water. We have found no pathological changes of intestinal epithelium in any experimental group.

Methods of processing and cryopreservation are believed to be the most important factors of long term clinical performance of biological heart valve prostheses. That is why we decided to cooperate in evaluating the impact of current AHV (allograft heartvalve) bank protocol on valve tissue morphology. AHV harvested from "heart-beating" cadaveric donors, considered as a fresh tissue, were compared with valve samples from non-heart beating donors, samples stored in saline, samples treated with antibiotic solution, and finally with cryopreserved valves, stored in liquid nitrogen for months. All samples were dissected, dried with hexamethyldisilazane (HMDS) method, gold-coated, studied and photographed in scanning electron microscope Tesla BS 301. Different superficial patterns were found on ventricular and vascular surfaces of "fresh" semilunar valves. We were able to detect early changes of endothelium after harvesting, denudation of endothelial covering during preservation with and without freezing. Our alternative method of drying samples by HMDS method proved to be suitable for thin membranes of human semilunar valves. Scanning electron microscopy seems to be helpful for morphological control of processing, cryopreservation and liquid nitrogen storage of AHV. We believe that further confrontation of morphological investigation with other methods helps us to develop more suitable protocol of handling AHV in heart valve banking.

Purpose: To report the use of hexamethyldisilazane (HMDS) as an alternative to critical point drying for preparing stented canine peripheral vessels for scanning electron microscopy (SEM)., Technique: Vascular specimens were fixed in 4% formaldehyde overnight, dehydrated in a graded ethanol series, followed by immersion in 100% hexamethyldisilazane. After air drying, the specimens were mounted on stainless steel stubs, coated with gold, and examined in the SEM. The electron micrographs were of high quality, showing the layers of the vascular wall and the incorporated stent covered by a neointimal layer. The micrographs were comparable to corresponding histological sections, but detailed endothelial patterns were more visible., Conclusions: HMDS treatment and subsequent air drying provides good quality scanning electron micrographs that reveal both endothelial patterns and the layered architecture of stented vessels. The disadvantage of HMDS drying may be a shrinkage and distortion similar to other drying agents. Ease of handling, low cost, and a high rate of success are advantages that favor HMDS desiccation over other drying methods.

The presentation describes an interesting finding of healed multiple war cutting wounds in adult male skull. The examined dry skull belong to the extensive osteologic collection which comes from the abolished "Broumov Ossuary". The set encompasses skeletal remains of the population from the 13th to 18th centuries.

Ethmoid cells display a considerable variability due to their extensive development. Pneumatization of middle turbinate intermediary one or several ethmoid cells is referred to "concha bullosa", which belongs to the frequent and clinically significant variations of bony nasal cavity. The collection of 309 (176 male and 133 female) adult dry skulls pertaining to the "Broumov Ossuary" (13th-18th centuries) was examined for the presence of concha bullosa. The appearance of the middle turbinate was evaluated by inspection. Only noticeably enlarged middle turbinates were rated as positive finding of concha bullosa. All positive findings of concha bullosa were also verified by their probing; coronal CT examination of the nasal cavity and paranasal sinuses was performed in seven of them. Concha bullosa was diagnosed in 160 skulls (51.77%).

Knowledge of topographic anatomy is essential prerequisite for any physician to be successful in professional career. That is why we pay special attention to topographic dissections completing course of normal human anatomy at our department. Dissection procedure is subjected to relatively rigid rules demanding removal of some superficial structures during preparation of deeper layers. Thus some important structures get lost for further learning and also for final evaluation of students knowledge and manual skills. Therefore we decided to introduce digital imaging into the recording of course of preparation, the topographic relationships and unique variations. Digital acquisition of pictures through still digital camera makes possible to bypass the wet photographic process and provides instant graphic inputs for further computer processing. The image files can be further edited, printed, archived on various media and then may be used for instructional, test, evaluative, and publication purposes. Moreover, own original pictorial material is feasible to be presented at anatomy lectures. Practical results of this new approach, besides higher attractiveness and motivation impact, allow us to conclude that systematic digital acquisition of dissection pictures combined with computer processing fairly increases quality of anatomical education.

Purpose: To evaluate expandable stents healed into vein wall as autologous vein stent-grafts for endoluminal grafting., Materials and Methods: Balloon expandable stents were placed into external jugular veins of eight dogs. Stent and vein patency was followed by ultrasonography. Five weeks after stent placement, jugular veins with endothelialized stent were harvested. The autologous vein stent-grafts were divided into two groups. In group A, autologous vein stent-grafts (n = 3) were placed immediately into Baker solution for microscopic examination. In group B, autologous vein stent-grafts (n = 3) underwent mechanical manipulation; they were compressed, mounted on angioplasty balloon, pushed through a 9-F sheath and dilated. The autologous vein stent-graft endothelialization and changes after mechanical manipulation were evaluated by light and electron microscopy., Results: Stent placement was successful in seven dogs. One stent migrated into the pulmonary artery. One well placed stent was damaged by compression dressing and thrombosed. At 5 weeks, gross and microscopic examinations revealed the autologous vein stent-grafts were fully covered by a 0.115- +/- 0.036-mm-thick neointimal layer. Small wall thrombus was observed in one autologous vein stent-graft. Repeated manipulations did not result in any intimal damage or stent loosening in the autologous vein stent-grafts., Conclusion: Expandable stents healed into a vein have potential to be used as autologous vein stent-grafts for endoluminal grafting without risk of disruption during percutaneous transcatheter introduction.

Behavioural effects of two experimental neurotoxins, mescaline and DSP-4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine), on retention of spatial orientation were studied in the T-maze. The stereotaxic administration of both neurotoxins into the selected brain structures was chosen to reveal this effect. The intensity and time course of the neurotoxic effect were dependent on the brain area administered. Nevertheless, the lengthening of the latencies in reaching the goal was generally more marked after mescaline in comparison with DSP-4.

The localization of a serine exopeptidase--DPP IV--in the male and female submandibular gland of the mouse during gland postnatal development was studied histochemically in the light microscopic level. The present results suggest that localization of DPP IV is closely related to the postnatal differentiation and maturation of acini and male granular convoluted tubules. Remarkable sex differences of DPP IV activity were detected in the submandibular gland of pubescent and adult animals. The possible physiological role of DPP IV in major salivary glands is also discussed in the paper.

Activity of alkaline phosphatase in the major salivary glands of male and female mice at various ages of postnatal life, and in females during lactation was studied histochemically. Enzyme activity was not detected on the day of birth, but was found in the terminal tubules of all major salivary glands during the first postnatal week. Alkaline phosphatase activity was increasing gradually with age and a definitive enzymatic pattern was observed by the age of 6 weeks. No difference in enzyme activity was found among the major salivary glands of young adult and old animals. The parenchyma of fully differentiated submandibular glands showed clear sexually dimorphic patterns of alkaline phosphatase activity. During pregnancy, a significant increase of alkaline phosphatase activity was detected in submandibular gland. From gestation day 15 to the end of pregnancy, enzymic pattern of granular convoluted tubules of pregnant females was the same as in the adult males. Histochemical masculinization of the submandibular gland during pregnancy suggests that besides androgens also progesterone exerts masculinization of the murine submandibular salivary gland.

Histochemical activity of DPP IV in the intracerebral homotransplants of submandibular gland of the newborn mouse was investigated in the course of a 5-month period after transplantation. Eight weeks after grafting, the enzyme pattern in the parenchyma of transplants was already comparable with the enzyme pattern of a fully mature mouse submandibular gland in situ. At this time, DPP IV was active in the apicolateral cell membranes of numerous acini of the gland transplants. Enzyme activity in apical cell cytoplasm of granular convoluted tubules was found only in transplants located in the brain of male recipients.

Toxicities expressed as LD50 values of O-alkyl S-(2-dialkylaminoethyl) methyl phosphonothiolates in different species and different routes of administration were determined. Rats were more sensitive to these compounds than mice, rabbits and guinea-pigs were more sensitive than mice and rats. The most sensitive to these compounds were dogs. LD50 values varied in a wide range, however, a decrease of toxicity was observed in the following rank: i.v., i.m., s.c., i.p., p.o. and p.c., respectively. Depending on the route of administration, LD50 values varied from 5 g/kg (i.m., dogs) through tens of microgram/kg for the most part of compounds and routes of administration to hundreds, rarely thousands of g/kg (some chemicals, p.c. administration).

Vascularization of some organs of rat following soman (O-pinacolyl methylphosphonofluoridate) intoxication was studied using scanning electron microscopy. Corrosion casts were prepared with commercially available methyl metacrylate monomer which was partly polymerized, supplemented with catalyst and accelerator and injected into the prewashed and fixed vascular bed. The obtained corrosion casts were sectioned and trimmed using a stereoscopic light microscope. Microvascular casts of normal organs', bed pattern were studied under scanning electron microscope and compared with vascularization patterns after soman poisoning. Changes in the vascular bed architecture of kidneys, brain, adrenal glands and thymus were described.

The effects of the repeated i.v. administration of daunorubicin (50 mg/m2, once weekly, max. 9 weeks) were investigated in rabbits in vivo to analyze biochemical and hematological changes. Noninvasive polygraphic records were used to evaluate the function of the heart. The administration of daunorubicin induced changes especially in levels of protein (decrease in total protein and albumin) and of some ions (decrease in calcium, magnesium and phosphorus) as well as in hematological parameters (decrease in erythrocytes, leukocytes and thrombocytes). The results obtained correlate with data on mechanisms of daunorubicin toxicity.

The authors describe the localization of monoaminooxidases oxidizing the protoxin MPTP to the active neurotoxic MPP+ ion, which induces parkinsonism by destroying the dopaminergic neurons of the nigrostriatum. Apart from some types of magnocellular neurons of the hypothalamus, enzymatic activity is localized in the endothelium of segments of the circumventricular vascular bed communicating with the enzymatically equally positive processes of the tanycytes of the third brain ventricle. The findings are briefly discussed from the aspect of the pathogenesis of experimental parkinsonism.

A corrosion casting method of the vascular bed of rat's organs using injection of methyl metacrylate resin was described. The casts were photographed in scanning electron microscope Tesla BS 300. Microphotographs of vascular bed casts of selected organs demonstrate the contributions and possibilities of scanning electron microscopy for the investigation of three-dimensional architecture and topographical relations of blood microcirculation in organs.

The study demonstrated lysosomal 2-glucuronidase activity localized in the marginal sinus epithelium of rat spleen. Immunologically, the marginal sinus is a key structure of the spleen and its enzymatic apparatus differs from that of the cells of the red pulp venous sinuses. The possible physiological significance of this finding is briefly discussed.