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PubMed1996

Rapid postmortem invasion of cecal mucosa of macaques by nonpathogenic Entamoeba chattoni.

Although Entamoeba histolytica is the third leading parasitic cause of death in the world, most infections in humans are asymptomatic and restricted to the intestinal lumen. Entamoeba histolytica infections have also been reported in most species of captive nonhuman primates, with New World monkeys being particularly susceptible to fatal invasive amebiasis. In contrast, Old World monkeys appear to be resistant to the disease, although tissue invasion in asymptomatic monkeys has been reported. Our initial objectives were to determine the incidence, the predisposing factors, and the light microscopic and ultrastructural features of invasive amebiasis in Macaca mulatta (rhesus) and and M. fasicularis (cynomolgus) macaques. Our findings indicate that nonpathogenic E. chattoni in macaques can invade cecal mucosa rapidly (within 1 hr) after death. Therefore, the presence of invasive Entamoeba trophozoites in routinely collected necropsy materials should be interpreted with caution, particularly in cases where tissue fixation is delayed.

Animals↗

PubMed1999

The current cardiac safety situation with antihistamines.

Antihistamines (H1-receptor antagonists) are amongst the most frequently prescribed drugs worldwide for the treatment of allergic conditions. The clinical interest of classical 'first generation' antihistamines is currently rather limited by their anticholinergic and sedative properties. The second generation of antihistamines, so-called non-sedating antihistamines, are free of these side-effects. However, since the 1990s, there have been reports that certain non-sedating antihistamines, mainly terfenadine and astemizole, might be associated with the risk of rare but severe dysrhythmias. These drugs prolong the monophasic action potential and surface electrocardiographic QT interval and may lead to the development of early after-depolarization and possibly torsades de pointes through an inhibition of potassium channel repolarization. Concomitant administration with drugs that inhibit the hepatic cytochrome P-450 (imidazole antifungals, macrolide antibiotics) or those that prolong the QT interval by the same or other mechanism (e.g. antiarrhythmics, antipsychotics, tricyclic antidepressants) increases their effect on the cardiac repolarization. The cardiac safety profile of newer non-sedating antihistamines requires confirmation. Drugs with low or no potential to block the K + rectification channel (e.g. IKr channels) are likely to possess cardiac safety advantages. Other drug-related factors such as the physico-chemical properties of the antihistamines and its metabolic profile may also contribute to the cardiac response. Mizolastine is a new non-sedating antihistamine with antiallergic properties. It has a good bioavailability and a metabolism via the cytochrome P-450 oxidation accounting for only 35% of its hepatic clearance. In addition, mizolastine displays low lipophilicity and consequently low cardiac tissue fixation. In clinical studies, mizolastine has not shown any dose-related increase in QT intervals. Its clinical use has not been associated with ventricular dysrhythmias. Thus, although the post-marketing experience with mizolastine is still limited, mizolastine offers a safe alternative for the therapeutic management of allergic rhinitis and urticaria. However, more data are still needed on the cardiac safety of this and other non-sedating antihistamines.

Benzimidazoles↗

PubMed2000

Pulpotomy reconsidered: application of an adhesive system to pulpotomized permanent primate pulps.

OBJECTIVE: This study was undertaken to compare the healing response of permanent primate pulps to pulpotomy procedures following hemorrhage control and adhesive hybridization to their response after conventional treatments. METHOD AND MATERIALS: Forty-two cavities were placed throughout the dentitions of 4 adult monkeys. In 24 teeth, following mechanical bur exposure and pulpotomy, hemorrhage was controlled with application of 3% sodium hypochlorite. The cavity was rinsed and the enamel-dentin-pulp surface was restored with an adhesive system for 6 and 7 months. Calcium hydroxide, formocresol, and resin-modified glass-ionomer cement were placed as conventional treatments in 18 teeth for 70 days and cavities were sealed with resin-modified glass-ionomer cement. Following perfusion fixation, tissues were demineralized, sectioned, stained, and histologically graded using defined criteria. RESULTS: Of 24 adhesive system pulps, 10 showed no or minimal pulpal response, 1 showed an acute response, 6 showed a chronic response, 2 showed a severe response, and 5 showed compartmentalized zones of localized necrosis. Only 8 adhesive system pulps showed stained bacteria associated with inflamed tissues. Thirteen adhesive system pulps showed dentin bridging directly at the adhesive system interface. Calcium hydroxide-treated specimens showed healing and dentin formation, while resin-modified glass-ionomer cement and formocresol treatments failed to result in any bridging. Apical tissues in all adhesive-treated specimens showed normal pulps and primary odontoblasts along their entire walls. CONCLUSION: Permanent pulps without periapical radiolucencies may survive pulpotomy, provided that hemorrhage is properly controlled and the pulp-restoration interface is hybridized to exclude all microleakage.

Animals↗

PubMed2001

Hemodynamic assessment of the Medtronic Mosaic bioprosthesis in the aortic position.

BACKGROUND AND AIM OF THE STUDY: The Medtronic Mosaic bioprosthesis (MMB) is a newly developed tissue valve which incorporates several features such as a low-profile semi-flexible stent, zero-pressure tissue fixation, and anti-mineralization pretreatment with alpha-amino oleic acid aimed to improve hemodynamics and prevent structural deterioration. METHODS: Between November 1995 to June 1999, 62 patients underwent aortic valve replacement (AVR) with the MMB; 41 of these who reached the one-year follow up interval and who had isolated AVR without any concomitant procedure with size 23 mm and 25 mm MMB were evaluated by serial echocardiography after three, six and 12 months. RESULTS: For size 23 mm valves, mean and peak gradients were 12+/-3 and 21+/-6 mmHg at 3 months, 12+/-3 and 20+/-5 mmHg at 6 months, and 12+/-4 and 20+/-6 mmHg at 12 months. For size 25 mm valves, mean and peak gradients were 13+/-2 and 22+/-4 mmHg at 3 months, 12+/-3 and 21+/-5 mmHg at 6 months, and 12+/-4 and 22+/-6 mmHg at 12 months. In patients with 23 mm MMB, left ventricular mass index (LVMi) was reduced from 181+/-34 g/m2 before surgery to 158+/-32, 150+/-28 and 140+/-25 g/m2 at 3, 6 and 12 months after AVR (p <0.001); in patients with 25 mm MMB, LVMi was reduced from 182+/-28 g/m2 before surgery to 165+/-25, 156+/-24 and 146+/-19 g/m2 at 3, 6 and 12 months after AVR (p <0.001). CONCLUSION: Our results indicate that MMB is associated with low mean and peak gradients and significant reduction in LVMi throughout the postoperative period. Thus, the MMB appears to be an excellent cardiac valve substitute in elderly subjects who require AVR.

Adult↗

PubMedDate not supplied

Chronic peritoneal inflammation by cyanate in rats.

OBJECTIVE: During peritoneal dialysis, the peritoneum is exposed to waste products, including urea. Urea forms cyanate spontaneously at body temperature and pH, and cyanate carbamylates amino acids, peptides, and proteins. Cyanate may contribute to peritoneal injury with morphological changes in the peritoneum. To test this hypothesis, we injected cyanate into rats. METHODS: Experiments were performed in two groups of 7 rats each. In the cyanate group, each rat received 1 mL of 1.5 micromol/L potassium cyanate dissolved in 40 mmol/L sodium bicarbonate solution intraperitoneally each experiment day. In the control group, each rat received 1 mL of 1.5 micromol/L potassium bicarbonate instead of potassium cyanate. The rats in both groups were anesthetized and killed at the 85th day after the first injection. After formalin fixation, tissue samples from abdominal walls and livers were sliced, embedded in a standard manner, and stained with hematoxylin and eosin. RESULTS: Parietal peritoneum from rats in the cyanate group showed a mild increase in the number of fibroblasts, with collagen deposits, infiltration by mononuclear cells, vascular congestion, round-shaped transformation of mesothelial cells, widening of submesothelial spaces, and abundant denudation of mesothelial cells. The visceral peritoneum from rats in the cyanate group showed collagen deposits with fibroblastic proliferation. CONCLUSIONS: Cyanate can induce chronic inflammation in the peritoneum, and exposure of the peritoneum to cyanate may contribute to peritoneal injury in patients being treated with peritoneal dialysis.

Animals↗

PubMedDate not supplied

[The structure of the skin of the ear in domesticated pigs, with special reference to their use for human dermatological research. 2. Specific histology of the integument].

Based on light microscopy, the study describes the specific histology of the ear integument of the white domesticated pig. After careful tissue fixation and embedding, routine histological staining, collagen fibre staining, fat demonstration based on frozen sections, and ink injection of the integumental blood vessel system were applied. A detailed description is presented of the structure of the skin layers (epidermis, dermis, hypodermis), the ear cartilage envelopes (fascia, perichondrium), the plica scaphae, the blood vessel distribution, the architecture of the collagen fibre bundles, as well as the hair follicles and the skin glands (sebaceous glands, apocrine tubular glands). The results are discussed with regard to a direct comparison with the histological structure of the human integument, and the advantages and disadvantages of the use of the porcine ear skin as model system in human dermatological research are emphasized.

Animals↗

PubMed1979

In vitro adherence of lymphocytes to unfixed and fixed high endothelial cells of lymph nodes.

Rat thoracic duct lymphocytes (TDL) bind selectively to venules lined by high endothelial cells (HEV) when overlaid onto glutaraldehyde-fixed frozen sections of lymph nodes. This report describes the characteristics of TDL binding to HEV in unfixed frozen sections and compares this reactivity with that observed after fixing sections with different reagents. We found that TDL bound to unfixed HEV and that the pattern of adherence to such sections was identical to that observed when using glutaraldehyde-fixed tissue. Fixation of the sections with glutaraldehyde, however, enhanced the binding reaction. This effect was also observed when sections were treated with the diimidoester, dimethylsuberimidate (DMS) but not when methanol or formaldehyde was used. Since glutaraldehyde and DMS are each bifunctional cross-linking reagents, the results suggest that in vitro HEV adherence was facilitated under conditions in which the endothelial binding sites were present in an aggregated form.

Animals↗

PubMed2001

Suggestions for HER-2/neu testing in breast carcinoma, based on a comparison of immunohistochemistry and fluorescence in situ hybridisation.

The arrival of Herceptin (Trastuzumab), an antibody against the HER-2 oncogene found in a proportion of breast carcinomas and other carcinomas, has emphasised the need for a standardised technique for demonstrating overexpression of HER-2. We compared the Dako A485 antibody and Dako HercepTest kit (HT) on a series of 122 breast carcinomas. Fluorescence in situ hybridisation (FISH) (Vysis) was performed on all cases with positive or equivocal immunohistochemical results. The Dako A485 showed HER-2 overexpression in 53% of carcinomas, while the HT showed 21% positive (HT 2+ 8%, HT 3+ 13%) and 79% negative (HT 0 67%, HT 1+ 12%). FISH for HER-2 gene amplification on all the HT 1+ and HT 2+ cases was negative, whereas FISH analysis of all HT 3+ cases was positive, with the exception of one case which could not be analysed for technical reasons. When histological subtype was analysed, only grade 3 infiltrating duct carcinomas were FISH-positive, suggesting that histological grading and subtyping may be able to triage carcinomas suitable for HER-2 testing. We suggest that the HT or a similar standardised immunohistochemical study for HER-2 can be used to screen breast carcinomas. We then recommend FISH where the carcinoma is HT 2+. FISH may also be appropriate in high grade, HT 1+ carcinomas where there are doubts regarding optimal tissue fixation or block storage conditions.

Antibodies, Monoclonal↗

PubMed2001

[Role of the pathologist in management of familial cancers].

Pathologists have long been in charge of the morphological analysis of human cancers, and have been used to be at the end of a chain in the diagnostic procedure. With the search for somatic mutations and new prognostic markers, the pathologists have become key-members in oncogenetics. New modalities for tissue fixation, microdissection of tumors, and forwarding of specimens to the molecular biologists are therefore requested. Two examples are presented to illustrate the need for tumor DNA, with the diagnostic utility of a microsatellite testing as a prescreening test in HNPCC tumors, and the search for new prognostic markers in some inherited predispositions to breast cancers.

Acetic Acid↗

PubMed2001

Comparative studies of nuclear DNA content in benign and malignant thyroid lesions.

Currently available data suggest that DNA aneuploidy is associated with aggressive behavior of and unfavorable prognosis in several malignant human tumors as compared with diploid malignancies. However, the diagnostic and prognostic importance of flow cytometric DNA measurements in the case of thyroid neoplasms remains controversial. Therefore, the aim of our study was to evaluate utility of DNA index (DI) and proliferative index (PI) in distinguishing benign from malignant thyroid lesions taking into account the possible influence of intra-tumor heterogeneity and tissue preparation mode on DNA flow-cytometry measurements. A retrospective study was performed on 71 paraffin-embedded specimens from 57 patients with benign and malignant thyroid pathologies: 13 colloid goitres, 12 parenchymatous goitres, 19 adenomas and 13 carcinomas. In 14 of 57 cases two separate specimens taken from different areas of the same lesion were analysed and DNA parameters were compared. Additionally, flow cytometry DNA analysis was parallelly performed on 3 adjacent but differently processed tissue sections (fresh, formalin-fixed and paraffin-embedded) taken from each of 26 surgically excised thyroid lesions. DNA content was also analysed in both fresh and formalin-fixed twin specimens of normal pig thyroid glands (N = 6). We demonstrated that all tumors diagnosed as thyroid carcinomas were associated with abnormal nuclear DNA content although aneuploidy was not found specific to malignant thyroid tumors. Aneuploid samples of benign thyroid lesions exhibited higher proliferative activity, expressed as mean PI values, than diploid ones. In carcinomas the mean PI values were significantly higher than in benign lesions, independently whether they concerned aneuploid or diploid tissues. Considering intra-tumor heterogeneity, the flow cytometric DNA parameters can be assumed as reproducible despite differences in the mode of tissue fixation and preparation for analysis.

Adenoma↗

PubMed2001

Prosthetic heart valves: why biological?

The replacement of heart valves only became feasible after the development of the heart-lung machine in 1953. Two groups of prosthetic heart valves were subsequently developed: biological valves that do not require anticoagulation and mechanical valves that require life-long anticoagulation with Coumadin. The incidence of heart surgery and the demographics of patients who require heart valve surgery vary worldwide; these factors influence the choice of prosthetic valve for the individual patient and are briefly reviewed. Improved biological tissue-fixation methods are also increasing the durability of biological prosthetic valves and will further favor the implantation of biological valves in the future.

Bioprosthesis↗

PubMed2002

Histomorphometric analysis of dentinal bridge formation and pulpal inflammation.

OBJECTIVE: The purpose of this study was to evaluate pulpal responses to the use of four resin composite materials as direct pulp capping agents. The importance and effects of individual pulp capping variables are not well understood; consequently histomorphometric analysis was used to analyze these variables. METHOD AND MATERIALS: Two hundred fifty standardized pulp-exposed cavities were prepared in nonhuman primate teeth. Exposed pulps were capped with calcium hydroxide and multistep and self-etching primer resin composites. Teeth were collected from 3 to 60 days to observe pulpal reactions. Following perfusion fixation, tissues were demineralized, sectioned, stained, and histomorphometrically measured. Bridge area, diameter of pulpal exposure, and cavity floor width were measured. Tunnel defects, operative debris, and pulpal inflammation were graded according to defined criteria. RESULTS: The variables correlated to dentinal bridge area were, in decreasing order of significance, time elapsed since exposure, diameter of pulpal exposure, pulp capping material, and tunnel defects. The variables correlated to pulpal inflammation were the type and curing of pulp capping material. Other variables were not statistically significant. CONCLUSION: Pulp capping with resin composite materials provided acceptable pulpal inflammatory and dentinal bridge repair responses, comparable with those of calcium hydroxide. Although resin composites are promising as direct pulp capping agents, further investigations are required to optimize their application protocols to reduce the penetration of potentially cytotoxic monomers into pulpal tissue.

Acid Etching, Dental↗

PubMed2002

Design of a suture anchor based on the superelasticity of the Ni-Ti alloy.

We have designed and manufacture a prototype of a new anchoring system for soft bone tissue fixation, based on the superelasticity of the Ni-Ti alloy. The anchoring capability has been observed in femoral hips by radiographs. The performance of this new anchor have been measured by tensile experiments and contrasted with finite element model. The results point out that keeping the fixation capacity, the new configuration presents advantages concerning to a minor damaged volume bone, a reduction of the manufacture cost and a simpler insertion.

Compressive Strength↗

PubMed2003

[The effect of SP-8-CPT-cAMP on the tracer coupling between the retinal ganglion cells and amacrine cells].

PURPOSE: To study the effect of SP-8-CPT-cAMP on the tracer coupling between the retinal ganglion cells and amacrine cells in rabbits. METHODS: The retinas of rabbit were cultured and treated with SP-8-CPT-cAMP .4% neurobiotin was injected into retinal single OFF-alpha ganglion cell with micro-injection, following tissue fixation with 4% paraformaldehyde, Cells were visualized with 1:600 streptavidin-Cy3. The intensity of tracer diffusing through the gap junctions among the ganglion cells and amacrine cells was calculated with confocal microscope. RESULTS: In the dendritic field of injected ganglion cells and cross the field some other ganglion cells(G1) and amacrine cells locating in the inner nuclear layer were stained. Two types of amacrine cells: brighter one (A1) and dimmer one (A2) were found. The intensity of neurobiotin in coupled G1,A1,A2 after treated with SP-8-CPT-cAMP is much higher than that of the untreated retinas. CONCLUSION: The gap junctions exist among the OFF-alpha ganglion cells and between OFF-alpha ganglion cells and amacrine cells. SP-8-CPT-cAMP increases the permeability of gap junction in OFF-alpha ganglion cell network.

Amacrine Cells↗

PubMed1976

[Tubular structure and germ cell distribution of cryptorchid or normal testes in early childhood (author's transl)].

INTRODUCTION: Many recent publications have demonstrated that the cryptorchid testicle (and, to a lesser extent, the descended partner) are progressively injured from the second year of life onwards. Do these injuries occur in an organ which has been healthy up to this time or are they superimposed on a structurally abnormal testicle? In order to answer this, parts of cryptorchid testicles, of the descended partners, and of normal testicles were compared by histological examination of serial sections. MATERIAL AND METHODS: Parts of four testes from children aged 4-7 months (2 specimens obtained by biopsy and 2 from autoptic material) and parts of four testes from children 1 1/2 years old (2 obtained by biopsy and 2 from autoptic material) were examined. The biopsies were fixed in Stieve's fixative. Tissue samples from clinically healthy children who had died suddenly were fixed in 4% formalin. The tissue was embedded in paraffin and sectioned serially; 6 mum sections were stained with HE. The spermatogonia in each cross-section and in each oblique section of a same tubule were counted and the counts of the latter were adjusted to a cross-section 50-60 mum in diameter. This counting technique did not alter the density of spermatogonia. The graphs present data on the density of spermatogonia through the lengths of the tubules examined and demonstrate tubular branching and blind ends. In the first year of life the cryptorchid testis and its descended partner showed repeated long sections lacking spermatogonia in the same tubule, whereas in normal testes the spermatogonia were more evenly distributed. The cryptorchid testis showed increased tubule branching in the areas examined. In the second year of life the tubules of the cryptorchid testis and its descended partner manifest areas free of germ cells, increased branching, and blind ends. The cryptorchid testis also had a tubule completely free of spermatogonia. The germ cell-free parts were always associated with a smaller tubule diameter than normal. The normal testes did not disclose increased branching or spermatogonium-free areas within similar lengths of tubules and showed an even distribution of spermatogonia. DISCUSSION: The different distribution of spermatogonia within the tubules and the increased branching of the tubules in cryptorchid testes indicate a previous disturbance of testis development.

Age Factors↗

PubMed2003

[Rehabilitation following anterior acromioplasty].

The shoulder region is one of the most challenging part of the human body to rehabilitate. Postoperative days following anterior acromioplasty are painful, with a high potential course of developing soft tissue fibrosis and joint contracture. In the past, following anterior acromioplasty and/or rotator cuff repair, the rehabilitation process was usually delayed for up to four to six weeks to allow healing of the repaired site. This conservative rehabilitation approach resulted in significant restrictions in glenohumeral and scapular joint mobility, weakness of the shoulder girdle musculature, prolonged pain, and functional limitations. Currently the trend of rehabilitation following anterior acromioplasty shifted toward a more earlier and aggressive approach thanks to improved surgical and soft tissue fixation techniques and advances in arthroscopic procedures. This has allowed active-assisted shoulder motion immediately after subacromial decompression and rotator cuff surgery. The rehabilitation team following anterior acromioplasty of the shoulder should consist of the physiatrist, orthopedic surgeon, physical therapist, and the patient.

Acromion↗

PubMed2003

[Study of apoptosis manifestations in streptozotocin diabetes mellitus].

The aim of this work was to study manifestations of apoptosis in pancreas, brain and myocardium of rats at the type I diabetes mellitus. To reveal the apoptotic changes in cells, specific damages of DNA were identified by the TUNEL-method. Specific for apoptosis changes in chromatin and cell membranes were found after counterstaining of a specimen by methyl green. In addition, the apoptotic and non-apoptotic cells were differentiated automatically with the help of image analyzing computer system by an index of optical density of cellular nucleus. This method allowed to find out for sure that apoptotic cells were available in all the studied tissues of healthy animals. However the possibility of their revealing by the TUNEL-method depends on the way of tissue fixation. Development of the type I diabetes mellitus was accompanied with an increase in the number of such cells, which gives evidence for an important role of apoptosis in diabetes pathogenesis.

Animals↗

PubMedDate not supplied

A modified technique for the diagnosis of Hirschsprung disease from rectal biopsies.

BACKGROUND: A diagnosis of Hirschsprung disease requires the demonstration of acetylcholinesterase fibres on frozen sections obtained from snap frozen biopsies of the rectum. This histochemical technique is generally not available in laboratories in developing countries. We improvised on the methodology of tissue preservation to make the staining technique more user-friendly, economical and reliable in demonstrating acetylcholinesterase activity in fresh rectal mucosal biopsies for the diagnosis of Hirschsprung disease. METHODS: Between June 1999 and May 2002 fresh rectal biopsies from 40 suspected cases of Hirschsprung disease were processed for routine frozen section (not snap frozen by liquid nitrogen) and stained by the Karnovsky and Roots method. These sections were assessed for the staining pattern of acetylcholinesterase fibres. The thickness of the nerve fibres and muscularis mucosa was assessed morphometrically. These were compared with biopsies obtained from 6 age-matched controls undergoing surgery for unrelated complaints. RESULTS: The sections stained for acetylcholinesterase by this improvised method of tissue fixation were good and crisp. A definite diagnosis of Hirschsprung disease was made in 25 cases and intestinal neuronal dysplasia in 1. The remaining 14 cases showed an equivocal staining pattern with no hypertrophic nerve bundles, thus excluding a diagnosis of Hirschsprung disease. The mean thickness of the submucosal nerve trunks measured in these enzyme-stained sections was found to be inversely proportional to the mean thickness of the muscularis mucosa. CONCLUSION: Our study on cryostat-cut sections suggests an inverse relationship between the thickness of the muscularis mucosa and the calibre of the nerve trunk--thinner the nerve trunk, thicker the muscularis mucosa and vice versa. Also, routine frozen sections, instead of snap frozen ones taken from a fresh rectal biopsy and stained by the Karnovsky and Roots method for acetylcholinesterase activity, are reliable for the diagnosis of Hirschsprung disease and are within the capability of a simple histopathology laboratory in a developing country.

Acetylcholinesterase↗