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At least 253 records · Page 14Linked to original sources
PubMed2000

Secretory characteristics and viability of human term placental tissue after overnight cold preservation.

Collection of human term placentae for research purposes is generally limited during working hours. Preserving placental tissue overnight might help to postpone experiments and, by extent, to increase material availability. In this study, fragments from normal placentae were incubated at 37 degrees C either immediately after delivery or after preservation at 4 degrees C in a HEPES-buffered solution or in a Roswell Park Memorial Institute (RPMI) 1640 culture medium. Protein, human chorionic gonadotrophin (HCG), human placental lactogen (HPL) and lactate dehydrogenase (LDH) contents within preserved explants were similar to those within freshly delivered ones. In contrast, HCG and HPL amounts released during incubation of preserved tissue were lower than with freshly delivered tissue. Differences were significant only during the first 3 h of incubation. Hormone releases were similarly Ca(2+)-stimulated, and Co(2+)- and low temperature-inhibited in preserved and freshly delivered tissues. After preservation, LDH leakage was also reduced. Furthermore, before and after 37 degrees C incubation during 6 h, preserved tissue was morphologically indistinguishable from freshly delivered tissue and showed neither higher incidence of DNA fragmentation, nor elevated caspase-3 activity, both of which are markers of apoptosis. This study validates an original, useful and rapid method to preserve placental tissue. Consequently, this preservation model may facilitate the study of physiological processes regulating placental hormone secretion in normal and pathological conditions.

Apoptosis↗
PubMed1978

Fatigue-induced damage in glutaraldehyde-preserved heart valve tissue.

Glutaraldehyde-preserved porcine mitral leaflet tissue has been subjected to extended accelerated fatigue loading in Ringer's solution containing 0.15% glutaraldehyde. Five tissue test pieces were subjected to cyclic tensile stresses of 50 and 200 Gm. per square millimeter and to 300 million to 800 million accumulated fatigue cycles. Tissue disruption occurred in each of the fatigued test pieces. Tensile loading, apart from reducing the acuteness of the collagen waveform and thereby decreasing tissue compliance, does not contribute significantly to the disruption process nor its rate of occurrence. Compressive flexure occurring during the unloading half of the fatigue cycle, however, does induce damage in the tissue. Mechanisms involved in the disruptive processes have been identified by conducting simultaneous morphologic and stress/strain observations on both the fatigued and unfatigued tissues in their wet functional condition. This vulnerability of the preserved tissue to compressive flexure could well affect the long-term durability of the glutaraldehyde-preserved heterograft valve, and this possibility is discussed in relation to the clinical use of these valves.

Animals↗
PubMed1991

Differential antigen preservation during tissue autolysis.

Immediate fixation or snap freezing of tissue is ordinarily done to maximize antigen preservation for immunocytochemistry; however, delay in tissue allocation or spontaneous lymph node infarction can render tissue suboptimal for immunostaining. To test the effects of tissue autolysis/necrosis on the preservation of various lymphoid, epithelial, and mesenchymal markers, two lymph nodes (one with reactive lymphoid hyperplasia and one with metastatic ductal breast carcinoma) were evaluated for immunocytochemically demonstrated antigen preservation at 0-, 4-, 8-, 12-, 24-, 48-, and 72-hour intervals of autolysis at 37 degrees C. All specimens were stained by frozen section and formalin-fixed paraffin section immunocytochemical reactions with antibodies against CLA (CD45), UCHL-1 (CD45RO), L-26, kappa, lambda, anti-epithelial keratins (AE-1 and AE-3), epithelial membrane antigen, and vimentin. Frozen sections were additionally stained for Leu-1 (CD5), Leu-2a (CD8), Leu-3a+b (CD4), Leu-4 (CD3), and Leu-14 (CD22). The most resilient lymphoid antigen preservation was observed with CLA and UCHL-1, both exhibiting immunoreactivity at 72 hours in both frozen and fixed preparations. L-26 showed similar reactivity in frozen sections, but detectable antigen was observed only up to 24 hours in formalin-fixed tissue. Leu-2a proved to be the most labile antigen, persisting for only 12 hours in frozen sections. The epithelial markers epithelial membrane antigen and AE-1 exhibited excellent antigenic preservation in both frozen and fixed preparations; AE-3 persisted well in frozen section but was not demonstrated in fixed tissue. Vimentin immunoreactivity was vastly superior in frozen, as compared with fixed, tissue sections. Most antigens showed remarkable preservation despite morphologic degradation; however, differential antigenic resilience was demonstrated. Knowledge of this variation in antigen decay is critical for evaluation of immunoperoxidase phenotypic studies of autolyzed or necrotic tissue.

Antigens↗
PubMedDate not supplied

[Chemoluminescence of preserved bone tissue].

The luminescence of bone tissue was studied during its treatment at preservation. It was found that vacuum drying as well as bone saturation with ascorbic acid and some antibiotics (streptomycin, monomycin) depressed the luminescence emission. Combined influence of these factors was found to be more difficult than for each one separately. The greatest deterioration of chemoluminescence intensity was observed during additional treatment with antimetabolite.

Anti-Bacterial Agents↗
PubMed2000

[Are there indications for cryogenically preserving ovarian tissue in gynecologic oncology?].

One of the essential goals of ovarian tissue cryopreservation is to preserve the fertility of young women who will be undergoing sterilizing anticancer treatments, as cryopreservation of sperm serves in men. However, maturation of gametes after thawing has not yet been realized in humans and pregnancies have only been obtained in animal models. It is nonetheless possible today to cryopreserve the ovarian tissue of patients who have nothing to lose as their follicular reserve would in any case be destroyed or severely depleted by cancer treatment. In gynecologic oncology, ovarian tissue cryopreservation may be performed when curative or prophylactic ovariectomy must be undergone, or when chemotherapy with high-dose alkylating agents is planned, particularly in cases requiring chemotherapy combined with pelvic radiation. These clinical situations may be encountered in young women and especially in girls with early-onset forms of ovarian, cervical, uterine, or vaginal cancers. These situations, nevertheless, remain rare as gynecological cancers occur most often in the post-menopausal woman.

Cryopreservation↗
PubMedDate not supplied

Surgical outcome of para-aortic lymph node dissection preserving neural tissue based on anatomical evaluations.

The anatomical distribution of the para-aortic lymph nodes was studied to establish an effective operative procedure that preserves neural tissue for patients with advanced gastric cancer. Para-aortic lesions were anatomically examined in 31 cadavers, and histologic preparations of 14 cadavers were used to evaluate the relationship between para-aortic lymph nodes and surrounding neural tissue. Surgical results were analyzed in patients with D3 gastrectomy based on anatomical findings (n = 33). Anatomically, the splanchnic nerves merged into the celiac ganglion, which consisted of either one ganglion (type I) or several ganglia (type II). The average number of lymph nodes were 17.4 in the area superior to the superior mesenteric artery (SMA) and 13.3 in the area inferior to the SMA. According to the number of metastatic lymph nodes (< or = 3, > or = 4), the median survival time was 14.7 and 9.7 months, respectively (P < 0.02). Patients either with or without metastatic lymph nodes behind the neural tissue had a median survival time of 14.7 and 9.7 months, respectively (P < 0.02). We conclude that para-aortic lymph node dissection preserving neural tissue is useful in patients with three or fewer para-aortic metastatic lymph nodes that are in front of the neural tissue.

Aorta, Abdominal↗
PubMed2001

40 years of tissue banking in Estonia.

A survey is given of the development of tissue banking in Estonia during 40 years, in which we address methods of tissue preservation, application of preserved skeletal tissues in orthopaedics as well as issues of clinical and experimental research in this area. Preparation and use of demineralized and morselized bone allografts has been significant during the last ten years. Progress of endoprosthetic joint surgery has essentially increased the need for bone transplantation in orthopaedics.

Journal Article↗
PubMed2004

Percutaneous pulmonary vein cryoablation to treat atrial fibrillation.

BACKGROUND: Cryothermic tissue injury, unlike hyperthermic tissue injury, preserves tissue architecture and causes less thrombus formation, and thus may prevent venous stenosis and stroke in ablating pulmonary veins (PVs) to treat patients with atrial fibrillation (AF). We investigate the feasibility, efficacy, safety and clinical outcome of using percutaneous cryoablation to treat such patients. METHODS: Thirty-one patients who had drug refractory paroxysmal (20) or persistent (11) AF underwent 37 PV ablative procedures using a 4 mm- or 6 mm-tipped 7F cryoablation catheter (CryoCath Technologies Inc., Quebec, Canada). Segmental isolation at the veno-atrial junction was guided by a distal circumferential mapping catheter. RESULTS: A total of 47 PV were ablated, of which 35/47 (74%) were electrically isolated and the remaining 12/47 had attenuation of PV electrograms, altered activation sequence, and marked slowing of left atrial-PV conduction. There was no change in PV diameter, either immediately following cryoablation (21 +/- 5 versus 22 +/- 6, p = 0.69), or at 18 +/- 9 months follow-up (22 +/- 5 versus 22 +/- 5 mm, p = 0.23). There was no clinical thromboembolic event. The duration of cryoablation for each treated PV and procedural duration was 65 +/- 39 and 290 +/- 101 min, respectively. Following cryoablation, 5/30 (6%) were free from AF and 12/30 (43%) showed improvement from previously ineffective antiarrhythmic drug therapy. 13/30 (43%) patients were unchanged by cryoablation. CONCLUSIONS: Cryothermic ablation shows great promise in reducing the risks of PV stenosis and thrombo-embolism associated with PV isolative procedures. However, cryoablation of these veins with linear catheters is time consuming, and the clinical outcomes are disappointing. Alternative catheter designs are required to overcome these difficulties.

Analysis of Variance↗
PubMed1975

Heterotransplantation of cultured human cancer cells and human cancer tissues into nude mice.

Twenty-seven out of 31 cultured human cancer cell lines transplanted subcutaneously into nude mice produced solid tumors. Direct transplantation of surgical materials proved less successful. In 35 attempts, only 1 of 6 gastric cancers, 2 of 3 liposarcomas, and 1 of 3 osteosarcomas were accepted. No positive tumor formation was noted after the inoculation of 3 nasopharyngeal carcinomas or 1 breast cancer. None of lymphomatous neoplasms and leukemias produced any tumor in 12 and 3 attempts, respectively. The histological and cytological characteristics of the tumors developed were studied with light and electron microscopes, in relation to the features in vitro and those of the parent tumors. Histological similarity of the tumors that developed in nude mice to their parent tumors were noteworthy. Serial transplantation was performed successfully in 9 cell lines and 2 tissues. Preservation of tissue construction ability and other differentiation abilities of in vitro cultured human cancer cells were ascertained in varying degrees.

Adenocarcinoma↗
PubMed1978

Assessment of a tissue transport-medium in preservation of tissue-fixed immunoglobulins and complement demonstrated by direct immunofluorescence. A pilot study with skin from SLE patients.

The present work was undertaken in order to test the value of a tissue transport-medium (Histocon) for direct immunofluorescence studies. For this purpose one skin biopsy was performed on each forearm of 26 patients with systemic lupus erythematosus. One of the specimens was left in ice-cold Histocon solution for 4, 8, or 20 hours, and the other was immediately quick-frozen. The results of the immunofluorescence tests with the two methods yielded similar results. It is concluded that the solution allows the preservation of tissue-fixed immunoglobulins and complement during short periods of transport.

Adult↗
PubMed1992

Microwave-stimulated glutaraldehyde and osmium tetroxide fixation of plant tissue: ultrastructural preservation in seconds.

Microwave-enhanced fixation of animal tissues for electron microscopy has gained in interest in recent years. Attempts to use microwave irradiation for the preparation of plant tissues are rare. In this study; I report on microwave conditions which allow a high quality preservation of plant cell structure. Tissues used were: internodes of Chara vulgaris, leaves of Hordeum vulgare, root tips of Lepidium sativum. Microwave irradiation was done with a commercial microwave oven (Sharp R-5975). Fixatives used were: 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer, pH 7.2 and 1% osmium tetroxide in veronal/acetate buffer, pH 7.2. Conventional fixations with glutaraldehyde/osmium were compared with microwave fixations. Examinations of thin sections showed that microwave fixation (glutaraldehyde or sequential aldehyde/osmium) is an attractive and rapid alternative method for processing plant tissues for electron microscopy. The optimal conditions found were: microwave oven at power level 50 W, 6.5 ml of fixative solution, irradiation times between 32-34 s, final temperature between 40 degrees C and 47 degrees C.

Chlorophyta↗
PubMed1992

Technical note: preservation of tissues and gastrointestinal tract portions by plastic coating or plastination.

Two methods to preserve gastrointestinal tract (GIT) organs and tissues, plastic coating (PC) and plastination (PN), were investigated and compared. Specimens to be preserved were removed from animals within 2 h of death and immediately cleaned with water. Digesta contents were removed by flushing desired portions of GIT with water until the exiting water was clear. In the PC method, cleaned specimens were dehydrated by immersion in an isopropanol solution, dried with forced air after positioning and orientation as in situ, and finally coated on the outer and inner surfaces with a clear plastic material. In the PN procedure, specimens were filled with, and submerged in, a low-formaldehyde fixative, then dehydrated by immersion in a cold acetone solution. Dehydrated specimens were immersed in silicone and placed in a freeze drier for impregnation under low vacuum, followed by overnight gas curing with a silicone crosslinker. Finally, viewing windows were cut out with a scalpel in GIT preserved by both methods. Preserved GIT and tissues had an appearance similar to their appearance in vivo. The PC method was simple and inexpensive. Plastinated specimens were more flexible, durable, and lifelike than those preserved by the PC method. In addition, many body parts, such as muscles, nerves, bones, ligaments, and central nervous system specimens, were preserved by PN. Both methods were found to be useful tools for postmortem studies of tissues and GIT organs.

1-Propanol↗
PubMed1983

Preservation of tissue specimens during transport to mycobacteriology laboratories.

Chloramine-T and sodium borate solutions were evaluated for their effectiveness in preserving Mycobacterium bovis and controlling the growth of non-mycobacterial contaminants on tissue specimens during transport to laboratories. The number of culturable M. bovis cells in suspension was reduced by 5.1 log10 upon exposure to chloramine-T solution and by less than 1 log10 upon exposure to sodium borate solution for 7 days. Reinoculation of laboratory media (because of overgrowth by non-mycobacterial contaminants) was required for 52.6% of 190 routine bovine tissue specimens shipped refrigerated in chloramine-T solution and for 6.1% of 520 specimens shipped unrefrigerated in sodium borate solution. M. bovis was isolated from bovine tissue stored in sodium borate solution at 23 degrees C for 17 weeks and at 4 degrees C for 25 weeks. Unrefrigerated sodium borate solution has been used successfully to ship tissue specimens to our laboratory for the past 11 years.

Animals↗
PubMed1985

K-Sol corneal preservation.

K-Sol, a new cornea preserving solution which contains no calf serum of foreign protein and is used for refrigerated storage of donor tissue, has storage procedures identical to those currently used for tissue preservation in McCarey-Kaufman medium. K-Sol can keep corneas alive and usable for penetrating keratoplasty for at least two weeks. The clinical results in a series of 17 patients indicated that tissue preserved in K-Sol for as long as two weeks, even when used by inexperienced surgeons in difficult or unfavorable cases requiring extensive anterior segment reconstruction, including reoperations or retained intraocular lenses, gave results virtually identical to those obtained with tissue preserved in McCarey-Kaufman medium for only two or three days.

Adult↗