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[Disorder in the efficiency of oxygen release to the tissues from preserved human erythrocytes and the rate of its regeneration during their perfusion of the isolated heart].

The main hemodynamic and oxygen supply parameters of the isolated rat heart (128 experiments) were measured during its perfusion with human donor red cells differing by storage duration and kind of hemopreservatives. The degree of the reduction in efficacy of oxygen release to myocardial tissue and the speed of the release restoration depended both on the red cell storage time and the preservative composition. The authors advocate a new preservative citroglucophosphate with adenine as it proved superior to all the preservatives studied.

Animals↗

Carcinoma of the ampulla of Vater: histopathologic analysis of tumor spread in Whipple pancreatoduodenectomy specimens.

Controversies exist regarding the application of the pylorus-preserving pancreatoduodenectomy (PPPD) to malignancies. This study was intended to disclose the pattern of spread of ampullary cancer and to substantiate that tumor spread at resectable stages does not involve the tissues preserved by PPPD. We examined 40 consecutive Whipple pancreatoduodenectomy specimens: mucosal cancer, 4 cases; cancer invading (but not penetrating) the sphincter of Oddi, 1; cancer invading the submucosa of the duodenum, 12; cancer invading the proper muscle of the duodenum, 5; cancer invading the subserosal layer of the duodenum, 7; and cancer invading pancreatic parenchyma, 11. Five cases of mucosal cancer or cancer invading (but not penetrating) the sphincter spread locally without nodal involvement and showed a 5-year survival of 80% without recurrence, being better (p < 0.05) than the 40% survival for patients with more advanced cancers. Sixty-three percent of the remaining 35 cases had metastasis to regional lymph nodes. The 5-year survival of 28% among those with cancer penetrating the proper muscle was worse (p < 0.05) than the 59% survival for those with less advanced cancers. No cases had involved the anatomic structures that would have been preserved by a PPPD. In three cases (7.5%), gastric cancer coexisted. In conclusion, ampullary cancer not penetrating the sphincter spreads locally. Once penetrating the sphincter, it often spreads regionally and causes recurrence. Cancer penetrating the proper muscle of the duodenum bears a worse prognosis. PPPD is an attractive alternative to the Whipple operation for ampullary cancer because no involvement was found in the tissue preserved by the PPPD. However, surgeons should be aware of a concomitant gastric cancer when doing a PPPD.

Adult↗

Preserved tissue-type plasminogen activator release and endothelium-dependent vasodilation in postmenopausal women with NIDDM.

We have recently shown that the net release of tissue-type plasminogen activator (t-PA) antigen can be rapidly enhanced by the muscarinic receptor stimulation in healthy males. Since diabetes mellitus has been associated with endothelial dysfunction, the aim of the present study was to compare the endothelium-derived local net release of t-PA with vasodilation in response to muscarinic receptor stimulation by metacholine (Mch) and fluid shear stress in a group of postmenopausal women with non-insulin-dependent diabetes mellitus (NIDDM), and to elucidate the influence of estrogen on this process. Six postmenopausal women with NIDDM were in randomized order exposed to step-wise intra-arterial infusions of Mch (0.1-0. 8-4.0 microg/min) and nitroprusside (SNP; 0.5-2.5-10.0 microg/min). Forearm blood flow (FBF) was assessed by plethysmography. The infusions with Mch and SNP were repeated during simultaneous intra-arterial infusion of 17-beta estradiol (E; 20 ng/min). During placebo infusion, FBF increased significantly in response to Mch and SNP (p<0.001), but no differences between Mch and SNP were found. In parallel to the blood flow increase in response to Mch stimulation, the t-PA net release was increased over 30 times (p<0.001). Estrogen did not produce any change in blood flow or net release of t-PA at baseline or in response to either drug (Mch or SNP). The present study demonstrates a preserved endothelium-dependent vasodilation and stimulated tissue-type plasminogen activator release in NIDDM postmenopausal women in response to Mch stimulation. Acute intra-arterial infusion of 17-beta estradiol did not affect the vasodilation or the t-PA net release.

Aged↗

A non-frozen living tissue bank for allotransplantation using green tea polyphenols.

Generally, mammalian cells and living tissues can be cryopreserved in a frozen state at very low temperatures over a long storage term. The survival rate of cell suspensions is often acceptable however, living tissues suffer a variety of injuries. In this paper, it was demonstrated that the addition of polyphenols extracted from green tea to conventional cell culture medium and tissue compatible liquid, can control cell proliferation and also preserve tissues for several months at ordinary room temperature, including such tissues as blood vessels, cartilage, islet cells and corneas. This protocol allows a non-frozen living tissue bank to be established using the preservation fluid described.

Animals↗

Identification of MEN1 mutations in sporadic enteropancreatic neuroendocrine tumors by analysis of paraffin-embedded tissue.

Gastrinomas and other gastrointestinal neuroendocrine tumors may occur sporadically or as part of the inherited syndrome multiple endocrine neoplasia type 1 (MEN1). Mutations in the recently identified MEN1 gene have been described in sporadic gastrinomas and insulinomas. This study describes techniques used to identify mutations in the MEN1 gene in DNA extracted from paraffin-preserved tissue. Two novel mutations are identified in the MEN1 gene from nine archived paraffin-embedded neuroendocrine tumors, demonstrating that retrospective genetic analysis can be used to identify mutations in the MEN1 gene from preserved tissue. Conditions are provided by which paraffin-embedded tissue can be used as a source of genetic material for sequence information of sufficient quality for mutational studies of the MEN1 gene. It should also be possible to apply this retrospective genetic analysis of paraffin-embedded tissue to other disease models.

DNA, Neoplasm↗

Computerized tomography of in vitro abdominal organs--effect of preservation methods on attenuation coefficient.

The effect of formalin, freezing, and refigeration on the attenuation coefficient of fresh abdominal tissue of rhesus monkeys and dogs was investigated over a 1-week period. These techniques were used individually and in combinations designed to simulate circumstances involved in future in vitro investigations of human specimens. Statistically significant alterations of attenuation coefficients were found to occur at all scanning times within the first week except for the first 48 hr of formalin storage. Refrigeration resulted in the largest alteration. The results indicate the attenuation coefficients of tissues preserved by these three methods may be altered and that the magnitude of the change will vary according to the preservation techniques, tissue, and duration between tissue death and scanning.

Animals↗

Effect of donor cornea preservation in tissue culture and in McCarey-Kaufmann medium on corneal graft rejection and visual acuity.

In a retrospective study the rate of rejection and clouding of the donor cornea for other reasons was investigated in 230 penetrating keratoplasties performed between 1984-1986. Donor corneas were stored in McCarey-Kaufmann Medium (MK) at 4 degrees C or in a modified Minimal Essential Medium (MEM) at 31 degrees C. No statistical differences in rejection rate, cloudiness due to other causes or visual acuity was found between MEM- and MK-stored donor corneas.

Adult↗

Degradation of macromolecules during preservation of lyophilized pathological tissues.

Methods of preserving biological specimens are becoming more important due to recent advances in molecular biological analysis. Storing samples in a freezer, however, is still the most commonly used method of preserving pathological specimens. We investigated the feasibility of using freeze-dried tissues stored at room temperature as an alternative method of preserving tissue samples for molecular analysis at the DNA, RNA, and protein levels. The freeze-dried tissues were transferred to a sealed vial filled with nitrogen gas and kept for months at room temperature. DNA and protein were stably preserved for at least 24 weeks. RNA, however, showed slight degradation after 10 weeks of storage. Controlling moisture and temperature during long-term storage was found to be important, as it significantly affected the stability of these cellular molecules in tissues. Shelf-stable preservation eliminates the need for storage in a freezer and allows convenient shipping of samples to distant places. These findings should provide practical basis for the development of a convenient and economical way of preserving pathological specimens for a variety of analyses in the field of molecular biology.

Animals↗

Ultracryotomy of biological tissues to preserve membrane structure.

A vacuum transfer stage is described which permits visualization of ultracryotome sections without the considerable distortions found in sections which have either thawed or rehydrated after freeze drying. Membrane structure-nucleus, nucleolus, mitochondria with their cristae and plasma membrane-was observed only in cells at the surface of the tissue which had undergone the fastest freezing rates. Inspection of knife damage in sections through these superficial cells showed that glass or diamond knives which are perfectly adequate for sectioning resin-embedded tissues are less suited to sectioning frozen biological tissue. Deeper in the tissue, where the freezing rates were slower, ice crystal cavities destroyed all membranous structures.

Animals↗

[Prerequisites for the use of preserved donor tissue in perforating and lamellar keratoplasty].

The longterm tissue culture is performed at the University Eye-Hospital of Hamburg since 1985 with a standardized procedure. The number of donor material and operations in the first 7 months of 1991 are reported. Preparation, storing and HLA-typing of the tissue are considered. The technical working up of the stored tissue for penetrating and lamellar keratoplasties will be explained.

Corneal Transplantation↗

Ionic liquids as an alternative to formalin in histopathological diagnosis.

Asymmetry of cations and the type of anions play a key role in the properties of ionic liquids (ILs) as fixatives for tissue preservation. 1-Methyl-3-octyloxymethylimidazolium tetrafluoroborate has proven to be a very good fixative, with similar effects as formalin. Our study shows that it is applicable for both histological and immunohistochemical purposes. After treatment with 1-methyl-3-octyloxymethylimidazolium tetrafluoroborate, tissue sections are more intensely stained. With respect to expression patterns and staining intensity, immunohistochemical staining is comparable in tissues fixed in formalin and the selected ILs. The present study demonstrates the properties of 1-methyl-3-octyloxymethylimidazolium tetrafluoroborate for tissue preservation in histopathological procedures, eliminating the requirement of formalin.

Borates↗

Autogenous bone graft in conjunction with enamel matrix derivative in the treatment of deep periodontal intra-osseous defects: a report of 13 consecutively treated patients.

AIM: The purpose of the present study was to investigate the effectiveness of a regenerative procedure based on supra-crestal soft tissue preservation in association with combined autogenous bone (AB) graft/enamel matrix derivative (EMD) application in the treatment of deep periodontal intra-osseous defects. METHODS: Thirteen consecutively treated patients, seven females and six males, aged 30-65 years, three smokers, were included. A total of 15 deep, one- to two-wall intra-osseous defects were selected. Immediately before surgery and 6 months after surgery, pocket probing depth (PPD), clinical attachment level (CAL), and gingival recession (REC) were recorded. RESULTS: PPD amounted to 9.4+/-1.8 mm before surgery, and decreased to 4.7+/-1.2 mm post-surgery (p<0.0000). CAL varied from 10.5+/-2.0 mm pre-surgery to 6.2+/-1.7 mm post-surgery (p<0.0000), with CAL gain averaging 4.3+/-1.4 mm. Fourteen (93.3%) defects presented CAL gain >/=3 mm. REC change was 0.4+/-0.7 mm. CONCLUSIONS: Results from the present study indicated that a regenerative procedure based on supra-crestal soft tissue preservation and combined AB/EMD treatment leads to a clinically and statistically significant improvement of soft tissue conditions of deep periodontal intra-osseous defects.

Adult↗

Therapeutic trial of hypercarbia and hypocarbia in acute experimental spinal cord injury.

Hypocarbia, normocarbia, or hypercarbia was maintained for an 8-hour period beginning 30 minutes after acute threshold spinal cord injuries in cats. No statistically significant differences in neurological recovery or histologically assessed tissue preservation were found among the three groups of animals 6 weeks after injury. No animal recovered the ability to walk. It is concluded that maintenance of hypercarbia or hypocarbia during the early postinjury period is no more therapeutic than maintenance of normocarbia. Mortality rates and tissue preservation data suggest, however, that postinjury hypocarbia may be less damaging than hypercarbia.

Acute Disease↗

Composite resins and bonded porcelain: the postamalgam era?

The growing demand of patients for esthetic or metal-free restorations, together with the ongoing interest of the dental profession for tissue-preserving materials have led to the actual development of posterior adhesive restorations. It is now clearly established that a new biomimetic approach to restorative dentistry is possible through the structured use of "tooth-like" restorative materials (composite resins and porcelain) and the generation of a hard tissue bond (enamel and dentin bonding). Scientific studies and clinical experience have validated use of bonded tooth-colored restorations, and we may have entered the so-called "postamalgam era". These significant changes have already impacted daily general practice, including pediatric dentists in California, but it is now critical to assure that the corresponding evidence-based process is integrated to the predoctoral programs statewide and nationwide. This paper reviews the foundations of this evolution, based on maximum tissue preservation and sound biomechanics, the so-called "biomimetic principle". Using scientific evidence and clinical experience, a model for the adequate use of current restorative systems is presented. This work, illustrated with cases with up to 10 and 14 years' follow-up, sets the ground rules for the clinical performance of the posterior esthetic restoration. Important considerations about tooth preparation, matrix techniques, layering methods, immediate dentin sealing and base lining are presented.

Advisory Committees↗

In situ localization of cartilage extracellular matrix components by immunoelectron microscopy after cryotechnical tissue processing.

Localization and distribution of proteoglycans within rat growth plate cartilage were investigated by immunoelectron microscopy. By use of a mixture of three monoclonal antibodies directed against chondroitin sulfate chains and of post-embedding staining by protein A-gold, the immunosensitivity and resolution achieved by electron microscopy within tissue processed by high-pressure freezing, freeze-substitution, and low-temperature embedding were compared with those in tissue preserved by three alternative procedures (i.e., mild chemical fixation in combination with either low-temperature embedding or conventional embedding, and high-pressure freezing and freeze-substitution followed by conventional embedding). The loss of matrix components incurred during each stage of high-pressure freezing, freeze-substitution, and low temperature embedding was also determined by measuring the loss of [35S]-proteoglycans from tissue labeled in vivo, and the results compared with previously determined estimates for tissue processed using conventional techniques. Immunosensitivity, determined as the number of gold particles per unit area, was highest in tissue processed by high-pressure freezing, freeze substitution, and low-temperature embedding. Comparable results (with a reduction of only 3-7%) were achieved within tissue preserved by mild chemical fixation followed by low-temperature embedding. In both procedures where conventional embedding was adopted, sensitivity was considerably reduced (by 51% for high-pressure freezing and freeze substitution and by 74% for mild chemical fixation). Loss of matrix components was negligible during all stages of high-pressure freezing, freeze-substitution, and low-temperature embedding. Such information, and that derived from morphological inspection of the various matrix compartments in cartilage processed by high-pressure freezing, freeze-substitution, and low-temperature embedding (J Cell Biol 98:277, 1984), together demonstrate that application of this technique results in successful immobilization of proteoglycans in situ within cartilage matrix. Although loss of proteoglycans from mildly fixed cartilage embedded under low-temperature conditions is minor, morphological examination of this tissue reveals considerable shifting of proteoglycans within matrix compartments. Hence, even though immunosensitivity may be high, resolution is poor. The beauty of the high-pressure freezing, freeze-substitution, and low-temperature embedding technique is that it combines high immunosensitivity with precise localization of matrix components at the molecular level.

Animals↗