Evolving indications and long-term oncological outcomes of risk-reducing bilateral nipple-sparing mastectomy.

Background: Bilateral nipple-sparing mastectomy (NSM) is a technically feasible operation and is associated with excellent cosmetic outcomes. The aim of this study was to evaluate trends in patient characteristics, indications for surgery and long-term outcomes of bilateral NSM for breast cancer risk reduction over time. Methods: A review of a single-centre experience with bilateral NSM performed between 2001 and 2017 for breast cancer risk reduction in patients without breast cancer was performed. Trends in patient characteristics and indications for surgery were evaluated over four time intervals: 2001-2005, 2006-2009, 2010-2013 and 2014-2017. Statistical analysis was performed using χ2 tests. Results: Over the study period, 272 NSMs were performed in 136 patients; their median age was 41 years. The number of bilateral NSMs performed increased over time. The most common indication was a mutation in breast cancer-associated genes (104 patients, 76·5 per cent), which included BRCA1 (62 patients), BRCA2 (35), PTEN (2), TP53 (3) and ATM (2). Other indications were family history of breast cancer (19 patients, 14·0 per cent), lobular carcinoma in situ (10, 7·4 per cent) and a history of mantle irradiation (3, 2·2 per cent). The proportion of patients having a bilateral NSM for mutation in a breast cancer-associated gene increased over time (2001-2005: 2 of 12; 2006-2009: 9 of 17; 2010-2013: 34 of 41; 2014-2017: 61 of 66; P < 0·001). Mean follow-up was 53 months; no breast cancers were found during follow-up. Conclusion: The use of bilateral NSM for breast cancer risk reduction is increasing and the indications have evolved over the past 16 years. These excellent long-term oncological results suggest that bilateral NSM is a good option for surgical breast cancer risk reduction.

Damage to the epithelial basement membrane in the corneas of diabetic rabbits.

Epithelial healing problems and basement membrane abnormalities have been observed in the corneas of patients with diabetes mellitus. In this study the rates of corneal epithelial wound healing following transcorneal freezing (with a 6-mm-diameter probe cooled in liquid nitrogen) were compared in diabetic (alloxan-induced) and nondiabetic rabbits. Also compared was the extent of injury to the epithelial basement membrane between the two groups. The overall rate of wound healing was faster in the diabetic animals; the wounds closed at 40 hours after freezing in diabetic animals and at 45 hours after in the nondiabetic controls. The lamina densa of the basement membrane was removed by the freezing procedure in two thirds of the diabetic animals but not in any of the controls. The results of this study indicate that epithelial healing problems in diabetes may be related to damage to the basement membrane, with resulting poor adhesion of regenerating epithelial cells.

Osmotic tolerance of rabbit and human corneal endothelium.

Rabbit and human corneas were mounted in a specular microscope and perfused with a balanced salt solution of varying osmolality (200 to 500 mOsm). Measurements of corneal thickness were made throughout the perfusion period, and at selected times the corneas were fixed and prepared for scanning and transmission electron microscopy. A hypo-osmotic perfusion medium caused an increase in corneal thickness; by comparison, a hyperosmotic perfusion medium decreased corneal thickness in both rabbit and human corneas. Despite the marked changes in corneal thickness and the water movement that occurred across the endothelium, the cellular ultrastructure remained intact. In reversal studies (return to 300-mOsm perfusion medium), corneal thickness returned to control values with no marked changes in endothelial cell structure. These data indicate that the corneal endotheium can tolerate a wide range of solution osmolalities (200 to 400 mOsm) without marked endotheial cell breakdown if the essential ions are present.

Effects of ionophores X537a and A23187 and calcium-free medium on corneal endothelial morphology.

Past studies have shown that apical junctional complexes (AJCs) of corneal endothelial cells break down in the presence of a Ca++-free medium. The purpose of this study was to examine the ability of Ca++ ionophores to maintain the AJCs in the Ca++-free media in both isolated perfused corneas and cultured endothelial cells. In addition, the ability of disintegrated AJCs to re-form when the endothelium is returned to a medium containing calcium ws also examined. Rabbit corneas were mounted in an in vitro specular microscope and perfused with a Ca++-free medium, or a Ca++-free medium containing 10(-5)M X537A or A23187 calcium ionophore. Also, confluent monolayer cultures of bovine corneal endothelial cells were placed in a Ca++-free medium or a Ca++-free medium containing 10(-5)M X537A or A23187 Ca++ ionophore and incubated for selected time periods. When junctional breakdown occurred, one cornea or culture plate was fixed for scanning and transmission electron microscopy (SEM and TEM), and the other was returned to a medium containing Ca++ and subsequently fixed for SEM and TEM. Both isolated perfused and cultured corneal endothelial cell AJCs exhibited marked disintegration in the presence of Ca++-free medium. The presence of an ionophore in the medium cultured cells. When returned to a medium containing Ca++, the corneas that had been perfused with Ca++-free medium containing an ionophore re-formed the junctions sooner than did those that had been perfused with a Ca++-free medium alone. These results suggests that the ionophores may be capable of mobilizing intracellular calcium to protect the AJCs.

Experimental Pseudomonas keratitis in the rabbit: bacteriologic, clinical, and microscopic observations.

Uniformly severe corneal infections were produced in rabbits by intracorneal injection of a few viable Pseudomonas aeruginosa. The bacteria multiplied rapidly, and within 24 hr, about 10 million organisms were present. The numbers remained stable thereafter. Polymorphonuclear leukocytes (PMNs) began to infiltrate peripheral stroma 24 hr after inoculation. By 32 hr, ring-shaped dense accumulations of PMNs were apparent in the anterior stroma with moderate stromal edema. By 48 hr, the anterior one third of central stroma was severely involved with abscess formation and loss of epithelium, and PMNs had invaded full corneal thickness. The area of liquefactive necrosis eventually involved the entire cornea from limbus to limbus, and collagen staining was lost. Transmission electron microscopy revealed the accumulation of small electron-dense particles in association with collagen fibrils and degranulating PMNs.

Ultrastructural identification of afferent fibers of cardiac origin in thoracic sympathetic nerves in the dog.

While cardiac afferent nerve activity has been recorded from the ventrolateral (VLCN) and ventromedial (VMCN) cardiac nerves, left dorsal and ventral ansae subclaviae, and left upper thoracic white rami communicantes, little anatomical evidence for the existence of afferent fibers in these nerves has been reported. This study was designed to characterize the normal ultrastructure of the above nerves and to identify afferent fibers in them through Wallerian degeneration produced by dorsal root ganglionectomy. Laminectomies followed by dorsal root ganglionectomies were performed on left thoracic roots T1-T4 in six mongrel dogs. The nerves to be examined were removed from two animals at 1, 2, and 3 weeks following ganglionectomy and prepared for electron microscopy. Control nerves were obtained from two normal dogs. Degenerating nonmyelinated fibers were characterized by watery axoplasm containing clumps of electron-dense material. Degenerating myelinated fibers were distinguished by the separation of their myelin lamellae, producing characteristic whorls. After three weeks, afferent nonmyelinated axons had degenerated in all nerves, leaving only layered processes of Schwann cells in these areas. Approximately 5-15% of the fibers in each nerve degenerated, indicating their afferent nature. Of these fibers, 85-90% were nonmyelinated C fibers and the remainder myelinated Adelta fibers. These results indicate participation of both Adelta fibers and a large population of C fibers in transmission of cardiac afferent activity.

Effect of thiol-oxidation of glutathione with diamide on corneal endothelial function, junctional complexes, and microfilaments.

Intracellular-reduced glutathione (GSH) was removed by thiol-oxidation with diamide during in vitro perfusion of the corneal endothelium. By 15 min the normal mosaic-like pattern of the endothelial cells was disrupted by serpentine-like lines of cell separation at the cell juntions. After 45 min of perfusion, infividual clusters of cells formed cup-shaped islands. The resultant exposure of Descemet's membrane to the perfusion solution resulted in corneal swelling. Transmission electron microscopy revealed that the endothelial cells separated at the apical junctions and that the microfilaments in the apical cytoplasm of cells formed dense bands, whereas the other subcellular organelles were normal in appearance. The change in cellular shape may be due to loss of cellular adhesion which results in the condensation of the microfilaments or contraction of the microfilaments. The addition of glucose to the perfusate prevented the diamide effect, and the diamide effect could be reversed upon removal and perfusion of a glutathione bicarbonate Ringer's solution. These results suggest that the ratio of reduced to oxidized glutathione in the endothelial cells plays a role in the maintenance of the endothelial cell barrier function.

Cytoplasmic activity in type I pulmonary epithelial cells induced by macroaggregated albumin.

After the intravenous injection of radioalbumin macroaggregate, large numbers of cytoplasmic inclusion bodies were observed in the lung tissue of rats. The inclusions were located mainly in the cytoplasm of type I alveolar lining cells, appeared 40 minutes after the injection, and lasted up to 2 days. These observations suggest that the type I alveolar lining cells participate in the clearing mechanism of the lung tissue, a function that thus far has not been attributed to this type of cell.