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PubMed1990

[Morphology of the corneal endothelium following preservation in dextran or chondroitin sulfate containing culture media].

The effects of dextran (group 1) and chondroitin sulfate (group 2) as additives to the culture medium in regenerated donor tissue preservation were investigated. In an experimental study, porcine corneas were incubated for 10 days at 4 degrees C in MEM with 1% chondroitin sulfate or MEM with 6% Dextran (MG 500,000). After a storage period, the corneoscleral disks were incubated in organ culture for 48 h at 32 degrees C, 1,016 cells of group 1 and 777 cells of group 2 were analyzed and the cell area, shape and number of sides were computed. In a control group we digitized 1,023 cells of 20 fresh porcine corneas. The mean area of the cells in group 1 was 345 +/- 212, in group 2 337 +/- 168; in the control group 263 +/- 59 microns2. In the statistical analysis of the data (U test), the preserved tissue had a significantly lower cell count and higher polymorphism than fresh tissue. When group 1 and 2 were compared no significant differences between the preservation media could be found.

Animals↗
PubMed2003

Microsurgical access flap and enamel matrix derivative for the treatment of periodontal intrabony defects: a controlled clinical study.

OBJECTIVES: Application of the guided tissue regeneration (GTR) principle and utilization of enamel matrix derivative (EMD) have both been shown to result in periodontal regeneration. While clinical investigations have demonstrated that the use of a microsurgical concept in combination with the GTR technique positively affects the percentage of primary closure and the amount of tissue preservation, no such information is available for EMD-treated periodontal defects. It was the aim of the present investigation to assess the clinical effect of the microsurgical access flap and EMD treatment with an emphasis on the evaluation of early wound healing. MATERIAL AND METHODS: Eleven patients displaying at least one pair of intrabony periodontal defects with an intrabony component of > or =3 mm participated in the study. At baseline and at 6 and 12 months after surgery, the following clinical parameters were assessed by a blinded examiner: oral hygiene status (API), gingival inflammation (BOP), probing pocket depth (PPD), clinical attachment level (CAL) and gingival recession (GR). Defects were randomly assigned to test or control treatment, which both consisted of a microsurgical access flap procedure designed for maximum tissue preservation. The exposed root surfaces of the test sites were conditioned with a 24% EDTA gel followed by EMD (Emdogain(R)) application. Primary flap closure was achieved by a 2-layered suturing technique. Postoperative healing was evaluated by a newly introduced early wound-healing index (EHI) at 1 and 2 weeks after surgery. RESULTS: Both test and control treatment resulted in a statistically significant mean CAL gain of 2.8 and 2.0 mm at 6 months, and 3.6 and 1.7 mm at 12 months, respectively (p<0.05). Differences in CAL gain between the two treatment modalities were statistically significant at both time points (p<0.05). Additional GR values after 12 months averaged 0.3 and 0.4 mm for test and control sites, respectively, and did not reach statistical significance (p> or =0.05). Two weeks after surgery, primary closure was maintained in 89% of the test sites and in 96% of the control sites. CONCLUSION: Both treatment modalities using the microsurgical flap procedure resulted in a high percentage of primary flap closure and maximum tissue preservation. In terms of PPD reduction and CAL gain, the combination with EMD application appeared to be superior to the microsurgical access flap alone.

Adult↗
PubMed1979

Penetrating keratoplasty using McCarey-Kaufman preserved corneal tissue.

Two hundred consecutive penetrating keratoplasties, using suitable donor corneas stored in modified tissue culture medium (M-K medium), were performed by a single surgeon over a 21-month period. Two hundred consecutive cultures of the donor corneosclearl rims for aerobic and anaerobic bacteria and fungi, done immediately after surgery, yielded 25 positive cultures for aerobic and anerobic bacteria and three for fungi. No clinical infections nor primary donor failures were encountered with patients after one to 21 months of follow-up. Preservation of excised corneas by trained technicians, under rigidly sterile, laminar-flow, tissue culture conditions appears to be a convenient, safe, and effective method of corneal preservation which permits elective keratoplasty.

Adolescent↗
PubMed2006

Taphonomic evidence for high-speed adapted fins in thunniform ichthyosaurs.

Ichthyosaurs have been compared with the fast-swimming thunniform groups of marine vertebrates, tuna, lamnid sharks, and dolphins, based on similarity of shape of the body and locomotory organs. In addition to shape, high-tensile stiffness of the control surfaces has been shown to be essential in maximizing hydrodynamic efficiency in extant thunniform swimmers. To date, there has been no evidence of a stiffening support system for the dorsal fin and dorsal lobe of the caudal fin in ichthyosaurs, the sole stiffening structure of the ventral lobe being an extension of the vertebral column along its leading edge. Stenopterygius SMF 457 is arguably the best soft-tissue preserved ichthyosaur specimen known. Here, we examine soft-tissue preservation in this specimen in the control surfaces and provide the first evidence of a complex architecture of stiff fibers in the dorsal and caudal fins. We find by comparisons and by analogy that these fibers provided a remarkable mechanism for high tensile stiffness and efficiency of the locomotory organs virtually identical to that of the great white shark, Carcharodon carcharias. It is the first mechanostructural study of the control surfaces of a Jurassic ichthyosaur that adds essential evidence in support of the view that these forms were high-speed thunniform swimmers.

Animal Structures↗
PubMed2000

Biological stability of RNA isolated from RNAlater-treated brain tumor and neuroblastoma xenografts.

BACKGROUND: Advances in molecular biological research have led to identification of prognostic factors such as Trk mRNA expression in primitive neuroectodermal tumors of the CNS and neuroblastoma. To study prospectively the importance of these prognostic factors in large groups of homogeneously treated patients, tumor specimens of good quality must be acquired, preserved, and stored at multiple institutions. Immediate freezing of tumor biopsy samples in liquid nitrogen and storage at -70 degrees C are the most commonly used method of tissue preservation for future RNA analysis. PROCEDURE: To evaluate alternative methods of preserving tissue samples for subsequent RNA analysis, we tested a new RNA stabilization solution. Using tumor tissue of two CNS tumor and one neuroblastoma human xenografts, we compared total RNA isolated from tumor tissue stored for 7 days at room temperature in stabilization solution to that of snap-frozen tissue. The quality of the RNA was studied by spectrophotometry, gel electrophoresis, RT-PCR, and gene expression profiling. RESULTS: No major differences were observed in the quality of RNA isolated from tumor samples stored at room temperature in the RNA stabilization solution compared to snap-frozen tumor samples stored at -70 degrees C. CONCLUSIONS: High-quality RNA can be prepared from tumor tissue stored at room temperature. Whenever snap freezing is not feasible, pieces of tumor tissue can be treated with RNAlater for subsequent RNA analysis. Short-term storage and shipment of well-preserved tumor tissue are clearly feasible for all institutions, thereby facilitating large multiinstitutional studies of biological prognostic factors.

Animals↗
PubMed1985

Leucocyte antigens in human post mortem tissues: their preservation and loss as demonstrated by monoclonal antibody immunohistological staining.

The development of monoclonal antibodies and of techniques for demonstrating antigens in situ in frozen tissue sections has been responsible for remarkable progress in diagnostic histopathology. We explored the potential of these techniques when applied to post mortem tissues that were frozen at various intervals after death and stained by monoclonal antibodies using immunoperoxidase technique. The monoclonal antibodies were selected according to their reactivity with essential markers of the lymphatic system and also to their availability. Lymph nodes and splenic tissue from 30 autopsy cases were stained in addition to thymic tissue from eight deceased infants. The antigens proved to be surprisingly well preserved. Staining could be precisely evaluated with UCHT1, OKT6 and anti-Leu-7 antibodies at least 72 h after death; staining with DAKO-pan-B, DAKO-LC and anti-Leu-3a was also very reliable. Antigens expressed by T-suppressor lymphocytes and dendritic reticulum cells were less well preserved. The T8-antigen of suppressor lymphocytes was usually demonstrable in the lymph nodes but less frequently in the splenic tissues. It is concluded that most leucocyte antigens are very resistant to post mortem disintegration, and that they can be reliably interpreted by immunohistological staining using monoclonal antibodies. We therefore recommend this in autopsy specimens in cases where in-vivo examination was not feasible.

Adult↗
PubMed1981

Effect of methylprednisolone in compression trauma to the feline spinal cord.

The purpose of this study was to determine the effect of methylprednisolone sodium succinate on clincal recovery and tissue preservation following compression trauma of feline spinal cord. Cats were anesthetized with pentobarbital and injured by placing a 170-gm weight on the spinal cord for 5 minutes. One hour after injury, the animals were given intravenous steroid (15 mg/kg/day) for 2 days in three devided doses, 15 mg/kg/day for 1 day intramuscularly, 7.5 mg/kg/day intramuscularly for 3 days, and 3.75 mg/kg/day intramuscularly for 3 days, for a total of 9 days. In a control group, the animals were injured but untreated. At 60 days after injury, the animals were sacrifieced by perfusion fixation with 10% formalin. The spinal cord was removed and evaluated for a number of morphometric parameters, including percentage of spinal cord cross-sectional area containing the cavity (%area) and percentage of spinal cord volume occupied by the cavity (%volume). A clinical recovery score (recovery index) was devised to evaluate neurological recovery. Steroid-treated cats showed significantly greater recovery than the untreated controls (p less than 0.001). Moreover, the spinal cord of treated cats displayed greater tissue preservation as measured by %area (p leass than 0.005) and %volume (p less than 0.004). Correlation coefficients comparing the recovery index with morphometric parameters revealed a negative correlation between cavity size and recovery. These data provide evidence for a beneficial effect of methylprednisolone in promoting recovery and preserving spinal cord tissue following blunt injury to the feline spinal cord.

Animals↗
PubMed2001

Determination of optimal transport conditions for biopsies of human articular cartilage as well as for suspensions of cultured chondrocytes used in autologous transplantation.

Autologous transplantation of chondrocytes is currently being promoted as a novel approach for the treatment of deep cartilage lesions. Briefly, the method involves enzyme-mediated release of chondrocytes from cartilage biopsies, the expansion of cells by in vitro cultivation and their re-implantation into the defect. The success of this technique depends on many factors including transport conditions for both, cartilage biopsies from the operating hall to the laboratory and the return transport of final suspension of cultured chondrocytes. To determine the extent of cellular damage in biopsies, chondrocytes were enzymatically isolated following a few days of tissue preservation in different tissue culture media. The proportion of dead cells was assessed by Trypan blue staining and counting. The viability was not dependant of the type of the medium used and remained approximately 50% in all samples, even after 72 h. To develop optimal conditions for transport of final chondrocyte suspension, isolated cells were firstly grown in monolayer cultures. Cell suspensions in media with different additives were injected into special glass containers used for the transport and left at 4 degrees C or 25 degrees C for up to 3 days. During this period every 24 h the samples were taken and viability as well as apoptosis levels were assessed. Viability of cells in suspensions at 25 degrees C decreased significantly and became inadequate already after 48 h. In contrast to that, the proportion of viable cells at 4 degrees C remained above 80% even after 48 h. In the majority of the samples, culture medium containing serum and vitamin C provided the best conditions for long-term preservation of chondrocytes.

Apoptosis↗
PubMed1982

Immunofluorescent labelling of K-papovavirus antigens in glycol methacrylate embedded material: a method for studying infected cell populations by fluorescence microscopy and histological staining of adjacent sections.

Trypsin and protease V (pronase) were studied for their ability to enhance immunofluorescent labelling of papovavirus antigens in glycol methacrylate embedded sections of organs infected with murine K-papovavirus. Treatment of Bouin's fixed sections with 0.4% trypsin for 30 minutes resulted in specific immunofluorescent staining equal to that seen in frozen sections and produced little if any loss of histological detail. Treatment with protease V resulted in less brilliant fluorescence and less satisfactory tissue preservation. Studies were then conducted to determine the fluorescence and less satisfactory tissue preservation. Studies were then conducted to determine the fixative which would produce brightest specific fluorescent antibody staining of papovavirus-infected cells while providing clearest definition of intranuclear inclusions and best morphological detail in histologically stained adjacent sections. Brightest immunofluorescence staining was accomplished on material fixed in 96% ethanol/1% glacial acetic acid or Bouin's solution. These fixatives also gave clear definition of intranuclear inclusions with histological stains and provided excellent morphological detail. Phosphate buffered paraformaldehyde/picric acid and 3.7% formalin gave less satisfactory fluorescence and obscured intranuclear inclusions in histological preparations. Sections fixed in 4% paraformaldehyde, 4% paraformaldehyde/1% glutaraldehyde, and 0.5 M p-toluenesulfonic acid were negative for specific fluorescence. Glycol methacrylate, used with proper fixation and trypsin pretreatment of sections, provides a useful embedding medium for immunofluorescent identification of virus-infected cells, and the 1.0-2.0 micron sections routinely obtainable with GMA permit study of individual infected cells by fluorescent antibody and histological staining of adjacent sections.

Acrylates↗