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Results for “tissue preservation”

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At least 19 recordsLinked to original sources
PubMed1979

Immunofluorescence of deparaffinized, trypsin-treated renal tissues. Preservation of antigens as an adjunct to diagnosis of disease.

The present study compares formalin-fixed, deparaffinized and trypsin-treated (DTT) renal tissue sections with frozen sections for detecting immune complex deposition. Both DTT and frozen sections from 52 renal biopsies were stained directly with fluorescein isothiocyanate-conjugated antihuman IgG, IgM, IgA, fibrinogen, and C3. DTT sections alone were stained indirectly for C3 using a double conjugate technique. Antigen presence or absence on DTT section was accurately detected in 90 per cent of biopsies for immunoglobulins and fibrinogen and in 75 per cent for C3 when compared to frozen section. Furthermore, antigen deposition was found in 21 per cent of biopsies only on DTT sections (usually because frozen tissue lacked glomeruli). Frozen sections alone were treated with reagents of the fixation-embedding process and directly stained for IgM and C3 to determine antigen stability. Alkaline or neutral formalin pH helped maximize antigen preservation. DTT sections are a valuable tissue source for adjunctive diagnosis of renal disease.

Antigen-Antibody Complex↗
PubMed2025

Real-world deployment of a fine-tuned pathology foundation model for lung cancer biomarker detection.

Artificial intelligence models using digital histopathology slides stained with hematoxylin and eosin offer promising, tissue-preserving diagnostic tools for patients with cancer. Despite their advantages, their clinical utility in real-world settings remains unproven. Assessing EGFR mutations in lung adenocarcinoma demands rapid, accurate and cost-effective tests that preserve tissue for genomic sequencing. PCR-based assays provide rapid results but with reduced accuracy compared with next-generation sequencing and require additional tissue. Computational biomarkers leveraging modern foundation models can address these limitations. Here we assembled a large international clinical dataset of digital lung adenocarcinoma slides (N = 8,461) to develop a computational EGFR biomarker. Our model fine-tunes an open-source foundation model, improving task-specific performance with out-of-center generalization and clinical-grade accuracy on primary and metastatic specimens (mean area under the curve: internal 0.847, external 0.870). To evaluate real-world clinical translation, we conducted a prospective silent trial of the biomarker on primary samples, achieving an area under the curve of 0.890. The artificial-intelligence-assisted workflow reduced the number of rapid molecular tests needed by up to 43% while maintaining the current clinical standard performance. Our retrospective and prospective analyses demonstrate the real-world clinical utility of a computational pathology biomarker.

Humans↗
PubMed1978

Insulin-releasing activity and successful transplantation of pancreatic islets preserved by tissue culture.

Preserving pancreatic islets for 7 days by a making use of the organ culture, we studied the insulin-releasing activity at the time of administration of glucose and various digestive tract hormones for the purpose of clarifying the function of preserved pancreatic islets. Furthermore, we transplanted pancreatic islets preserved for 3 to 5 days into the portal vein of rats with streptozotocin-induced diabetes and reached the following conclusions: (1). The islets of Langerhans of the pancreas responded well to glucose up to the seventh day of preservation and showed patterns similar to those of fresh pancreatic islets with respect to both the dose response and the time response. (2). Preserved pancreatic islets of the pancreas had insulin-releasing activity almost equal to that of fresh pancreatic islets against stimulation by glucagon, tolbutamide, and various digestive tract hormones. (3). Rats with streptozotocin-induced diabetes showed a marked improvement in blood glucose and urine glucose following transplantation of preserved pancreatic islets into the portal vein, and this effectiveness persisted for 6 to 8 weeks.

Animals↗
PubMed1978

Periodontal and pulpal healing of monkey incisors preserved in tissue culture before replantation.

The effect of delayed replantation and tissue culture as a prevention against root resorption was examined in green Vervet monkeys (Cercopithecus aethiops). Extracted incisors were kept in tissue culture medium (Eagle's medium) for 5--14 days before replantation. The extra-alveolar dry period before tissue culture ranged from to 0 to 60 min. Incisors not subjected to tissue culture served as controls. The animals were sacrificed 8 weeks after replantation. The following histologic parameters were registered for each tooth: surface resorption, inflammatory resorption, replacement resorption (ankylosis), downgrowth of pocket epithelium, and periapical inflammatory changes. The evaluation of the pulp included the extent, recorded in mm, of pulp survival. Histometric evaluation showed that teeth immediately placed in tissue culture medium for 5--14 days showed improved periodontal healing, exhibiting significantly less inflammatory resorption than control teeth immediately replanted. Also the extent of pulp survival was significantly increased in teeth replanted after tissue culture. Teeth bench-dried for 60 min and thereafter placed in tissue culture medium also showed a significant reduction in the amount of inflammatory resorption and increased amount of pulp survival compared with control teeth replanted after the 60-min dry extra-alveolar period. Replacement resorption (ankylosis) was found in all teeth in both groups.

Animals↗
PubMed1979

Effect of sodium azide on the ultrastructural preservation of tissues.

An electron microscopic study was carried out to examine the quality of ultrastructural preservation of parenchymatous and mesenchymatous tissues and isolated cells fixed in glutaraldehyde with sodium azide (NaN3) as an additive. The dense tissues fixed with conventional glutaraldehyde containing calcium chloride demonstrated only a narrow zone of good tissue preservation on the surface of the specimens. Addition of azide at a concentration of 0.1% greatly improved the cellular preservation in the deeper region of tissues, in particular with respect to the mitochondrial morphology. There was no adverse effect on other cell organelles. The improvement in mitochondrial preservation and the enhancement of penetration of the fixative is presumably due to selective and instantaneous inhibition of mitochondrial metabolic activity by the azide, thus retarding anoxic degenerative effects on cellular structures until permanent fixation is completed by the comparatively slow-acting aldehyde. However, the addition of azide offers no significant improvement in the ultrastructural preservation of isolated lymphocytes and liver cells, or fibroblasts maintained in culture.

Animals↗
PubMed1978

Tissue culture preservation and intramuscular transplantation of pancreatic islets.

Pancreatic tissue from neonatal rats was cultured for 6 days and then transplanted into isologous animals made diabetic with streptozotocin. The cultured pancreatic tissue was implanted either into the peritoneal cavity or into muscle pockets and showed survival by functional and morphological studies for longer than 40 weeks. Pancreatic tissue from a patient subjected to subtotal pancreatectomy for chronic pancreatitis was maintained in culture for 7 days, with evidence for insulin release into medium, sterility, and histological viability of islets. Autotransplantation of this tissue into muscle pockets of the forearm was tolerated well. Glucose tolerance improved following transplantation, but evidence for function of the graft (insulin, C-peptide) remains inconclusive, 4 months after transplantation.

Animals↗
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↗
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↗
PubMed1979

Donor cornea contamination with McCarey-Kaufman medium preservation.

A patient had corneal infection with Staphylococcus aureus after keratoplasty from tissue preserved in McCarey-Kaufman medium. The small, successfully treated corneal infection was from the same organism cultured from the tissue culture medium at the time of transplantation. Possible sources of donor-tissue contamination included the increase in ocular flora seen in postmortem eyes, blood-borne bacteria, lack of sterile technique in securing donor tissue, inadequate irrigation of the tissue, and inadequate use of topical antibiotics on the tissue. Preservation medium and specimens from medium-preserved and refrigerated corneas should be cultured before and during surgery.

Administration, Topical↗