Differentiation of hepatic cavernous hemangioma from metastases by rare sequence MR imaging.

In this study, in order to differentiate cavernous hemangioma and hepatic metastases, rapid acquisition relaxation enhanced (RARE) sequence was used. First, in vivo measurements of T1, T2 relaxation times and proton density were obtained using T1, T2 calculation protocol (TOMIKON S50, 0.5T) and multipoint techniques. These measurements were made from regions of interest placed over the liver, spleen (because of similarity of relaxation time values between hepatic metastases and spleen) and cavernous hemangioma (HCH). Based on these intrinsic parameters, T2 curves signal intensity of three different tissues were constructed. At TE = 500 ms, the signal intensity of the liver and spleen has been near zero whereas in HCH, the signal intensity remained. As RARE sequence is very similar to spin echo (SE), by replacing effective TE(ETE) = 500 ms in the RARE equation, two dimensional contrast-to-noise ratio (CNR) contour plots were constructed demonstrating signal intensity contrast between liver-spleen, liver-Hemangioma for two different scan times (3 min, 7.5 s) and pulse timing. Then, optimal RARE factor and inter echo times were obtained in order to have maximum CNR between liver-Hemangioma and minimum CNR between liver-spleen. These optimal parameters were performed on ten normal and five persons with known HCH. Images showed that in both scan times (3 min, 7.5 s); the liver and spleen were suppressed whereas the HCH was enhanced. The image quality in the scan time of 3 min was better than the scan time of 7.5 s. Moreover, in this study, two different sequences were compared: i) Multi-slice single echo (MSSE) for T1 weighted image ii) RARE (ETE = 80 ms) for T2-weighted image. This comparison was done to show maximum CNR between liver-spleen (metastases) and to choose a better sequence for detecting metastases. CNR in the RARE sequence was more than in the MSSE sequence.

Hemangiopericytoma of the ciliary body.

A 60-year-old woman had a ciliary body tumor that resembled an amelanotic malignant melanoma by clinical examination. The magnetic resonance imaging scan correlated with the clinical diagnosis. Because of apparent rapid growth, her eye was enucleated. However, histopathologic examination revealed a highly vascularized, spindle-cell tumor harboring immunoreactive actin and vimentin. Electron microscopy further supported the diagnosis of hemangiopericytoma with smooth-muscle differentiation. To our knowledge, this is the first report of a hemangiopericytoma of the ciliary body.

Pars planitis and autoimmune endotheliopathy.

A migrating endothelial rejection line is the clinical criterion of specific immune reaction in corneal allotransplantation. This line when seen in otherwise intact corneas has been presumed to be an autoimmune endotheliopathy. We have recorded corneal changes similar to autoimmune endotheliopathy in four of ten patients with the diagnosis of pars planitis. These observations suggest that pars planitis may be an autoimmune process directed against the vitreous humor.

Corneal endothelium in penetrating keratoplasty.

Specular microscopy of endothelium after corneal transplantation has often shown a sharp reduction in its number density immediately after surgery and long-term cell loss during the next three to four years in addition to continuous morphologic changes. We examined flat preparations of the endothelium of three corneal buttons removed three weeks, eight weeks, and 11 months after penetrating keratoplasty and compared them to similar preparations from the corneal rims of the respective donors. We did not find significant morphologic changes, and direct endothelial cell counts disclosed an endothelial cell loss of 3.8% at three weeks, 2.6% at eight weeks, and 5.6% at 11 months after keratoplasty. We believe the lack of endothelial cell loss and absence of morphologic changes in these specimens are direct results of our surgical technique.

In vitro enhancement of anterior chamber GVH reactions.

The injection of sensitized allogeneic lymphocytes into the anterior chamber of the rabbit eye results in a local graft-verus-host reaction, with focal destruction of the corneal endothelium. This experimental model permits in vitro manipulation of effector cells, and the study of the mechanisms involved in corneal graft rejection. The authors now show that the in vitro activation of sensitized lymphocytes is a one-way mixed lymphocyte reaction yields "supersensitized" effector cells which are quantitatively enriched and qualitatively altered to yield more severe and more rapid endothelial target cell destruction.

Diurnal variation in corneal endothelial morphology.

Transient changes in the corneal endothelium were the earliest detectable response to low atmospheric oxygen in experimental animals. Similar changes have been reported after hard and soft contact lens wear. We describe widespread transient cell changes by wide-field specular microscopy in the normal corneal endothelium after 12 hours of a light eye patch. The relative anoxia of lid closure during normal sleep appears to be the cause of observable changes. This observation questions the safety of extended wear contact lens over a prolonged period of time, and its significance to age-related endothelial cell density reduction and cornea guttata remains to be seen.

Specular microscopy of hard contact lens wearers.

Wide-field specular microscopy, slit-lamp examination, and pachometry were performed on 22 successful hard contact lens wearers and 22 controls matched for age, race, sex, and refractive error. A minimum of 600 cells per control and 1200 per contact lens wearer were manually digitized from the specular photomicrographs. Frequency distributions of cell areas were compared between the two groups using the parameters of mean, median, standard deviation, coefficient of variation, skewness and kurtosis. Slit-lamp examination was normal and there was no significant difference in corneal thickness between the patient group and the control group. Comparison of mean, median, and standard deviation also revealed no significant difference, but skewness (P less than .001), kurtosis (P less than .001) and coefficient of variation (P less than .004) were greater in the hard contact lens wear group. Hard contact lens wearing time correlated with increasing pleomorphism (P less than .05). Specular microscopy also revealed morphologic changes including deep stromal striae, intra- and extracellular "blackout" areas, and clustering of extremely small and large cells. The possible relationship between endothelial hypoxia and structural stromal changes are discussed.

Ocular effect of neodymium-YAG laser.

We aimed a high-powered pulsed neodymium-YAG laser incrementally from air to the anterior portion of the vitreous in rabbits to evaluate its effect on the corneal endothelium, the lens, and the dynamics of intraocular fluid. Corneal endothelium damage occurred as much as 3.5 mm away from the site of optical breakdown. The degree of tissue damage was inversely proportional to the distance from the site of optical breakdown, and the damage pattern at a given distance was the same whether the optical breakdown was anterior or posterior to the corneal endothelium. A single 4-mJ shot (mode-locked train) of laser light causes disintegration and liquefaction of the lens in a spherical area 300 micron in diameter. The damage extends posteriorly to a distance of 450 micron. The effect of this explosion denatures the surrounding cortical fibers for an area of 50 to 80 micron. Increased intraocular pressure was noted in all instances of anterior or posterior capsulotomy, probably as a result of the release of liquefied cortical material and mechanical obstruction of the chamber angle. No increase in intraocular pressure occurred when the lens capsule remained intact.

Corneal grafts in the second eye.

A series of 51 patients with bilateral penetrating corneal grafts was followed for 1-12 years to assess the effect of the second eye corneal graft on the incidence of allograft rejection. In 33 patients (66 eyes) who had avascular grafts, there was no significant increase in the incidence of allograft rejection reaction after corneal transplantation in the second eye. In 18 patients (36 eyes) who had vascularized corneas, there was a twofold increase in the incidence of allograft rejection in the second as well as in the first corneal graft. Based on this observation and other reports cited in the literature, we offer contraindications for grafting of the second eye.

Coagulation properties of intraocular humors and cerebrospinal fluid.

Clinical observations indicated a prompt cessation of episcleral capillary bleeding after exposure of those tissues to aqueous humor during intraocular surgery. Based on this observation, both aqueous and vitreous humors were obtained from eyes provided by an eye bank and from human eyes prior to intraocular surgery. Samples of cerebrospinal fluid also were obtained from two patients, one with optic atrophy and another with nutritional amblyopia. A total of 49 specimens were studied. Aqueous humor shortened the average ear lobe puncture bleeding time from 4.74 +/- 0.2 to 1.13 +/- 0.1 minutes. Varying dilutions of aqueous humor, up to a dilution of 1:16, shortened prothrombin and partial thromboplastin times when compared with normal control plasma without aqueous. Vitreous humor shortened partial thromboplastin time but had no effect on prothrombin time. The effect of cerebrospinal fluid on prothrombin and partial thromboplastin times was similar to the aqueous, but to a lesser degree.

Presumed autoimmune corneal endotheliopathy.

Two men (58 and 19 years of age) had an unusual recurrent, bilaterally symmetric disease process involving the cornea. It is characterized by stromal edema progressing centrally from the periphery in otherwise normal eyes. The corneal edema in each instance was closely associated with slowly moving linear keratic precipitates accompanied by the destruction of the endothelium, with minimal anterior chamber reaction. There was no history of herpetic keratitis or trauma, and serologic tests for syphilis were negative in both cases. A similar pattern of linear endothelial destruction has been reported heretofore only in association with corneal allograft rejection. This clinical pattern, the cytologic findings for the aqueous humor (macrophages and lymphocytes), and the rapid response to corticosteroid therapy suggested that an autoimmune process was the underlying cause of this disease.

Desquamation of corneal endothelial cells.

The process of wound healing of rabbit corneal endothelium involves the desquamation of significant numbers of endothelial cells, which may be found floating freely in the aqueous. It is suggested that this may be a general phenomenon of corneal endothelial wound healing, which accompanies the release of endothelial-cell attachments to Descemet's membrane and to neighboring cells during mitosis, allowing some of the cells to "fall of" into the anterior chamber. The possibility is discussed that such endothelial desquamation may contribute to had sensitization to he histocompatibility antigens of penetrating corneal grafts.

Advantage of underweight.

Exposure measurements made during a diagnostic radiological study revealed that heavy set patients pay a higher price in absorbed dose than lighter people.

Transfer of bacterial infections by donor cornea in penetrating keratoplasty.

A 45-year-old man died of Hogdkin's disease complicated by peritonitis and possible septicemia. His corneas were used for transplant in a 26-year-old man with advanced keratoconus and a 42-year-old man with vascularized central leukoma of old herpetic keratitis. Both recipients developed a fulminating endophthalmitis with Pseudomonas aeruginosa. We believe that the donor corneas, although clinically normal, were heavily infected, with signs of inflammation possibly suppressed by the Hodgkin's disease.

Microtropia.

Evaluation of 50 cases of microtropia that were collected within two years indicates the primary form of microtropia to be more common than the secondary form (48:2 cases). Various degrees of anisometropia were present in all cases of primary microtropia, suggesting that anisometropia is the cause rather than the consequence of microtropia.

Spontaneous regression of retinoblastoma.

Clinicopathologic evidence of bilateral spontaneous regression of retinoblastoma in three brothers is presented. The buphthalmic right eye and phthisical left eye of one of these persons were examined histopathologically. The two brothers of this patient both had phthisical left eyes, and those eyes were examined histopathologically. Both of those brothers also had clinically detected chorioretinal scars in their right eyes from regressed retinoblastoma. Three of eight children of one of the two brothers had bilateral retinoblastoma, and two of seven children of the other brother had bilateral retinoblastoma. Reports in the literature of 50 previous cases of total spontaneous regression of retinoblastoma from 1911 to 1975 are reviewed.

Induction of corneal graft rejection by passive cell transfer.

An experimental model is presented demonstrating that penetrating corneal grafts in the rabbit may be rejected by passive transfer into the anterior chamber of specifically sensitized lymphoid cells. Destruction of histo-incompatible corneal endothelium is always marked by the formation of focal pock-like areas of damage in this system, rather than by the typical moving line of rejecting endothelium usually seen in spontaneous graft rejection. Where the transferred lymphoid cells are compatible with the tissues of the graft recipient, the picture is one of a severely affected graft on a field of uninvolved recipient corneal endothelium. Where the lymphoid cells are compatible with the graft and not with the tissues of the recipient, one sees a clear corneal graft surviving on a field of endothelial destruction on the recipient bed. The specificity of these reactions is illustrated in terms of the histocompatibility relationships between corneal donor, graft recipient, and the donor of the sensitized lymphoid cells.

Physiological function of regenerating endothelium.

A defined area, 4 mm. diameter, cryothermal injury was created on a rabbit cornea. Corneal thickness was measured at four distances from the limbus to the center of the cornea during the swelling phase after endothelial damage, and during the recovery period. Rapid initial swelling was followed by a period of stable maximum thickness over 24 hours. More swelling occurred centrally than peripherally. Eight days after injury the peripheral cornea regained normal thickness, and the central portion was normal thickness after 10 to 12 days. Histological examination of corneal endothelium showed that early migration of cells into the denuded area occurred 6 hours after injury. By 2 days, most of the denuded area was covered by endothelial cells, although the cells were large and irregular. The number of normal cells increased, and of irregular cells decreased, over the next five days, until two weeks after freezing all cells had a normal appearance. The recovery of physiologic endothelial function lags behind the histologic recovery by about four to five days, indicating that recovery of the normal endothelial permeability is possibly related to the status of the cellular junctions rather than covering of the posterior surface by cells per se.

Local graft versus host reactions within the anterior chamber of the eye: the formation of corneal endothelial pocks.

Introduction into the rabbit's anterior chamber of lymphoid cells sensitized to the histocompatibility antigens of the recipient leads to the development of an intraocular graft versus host reaction. This takes the form of a more-or-less severe uveitis, and the production of small focal areas of endothelial cell destruction on the posterior surface of the cornea. In the milder responses, these present as discrete pocks on the endothelial layer, which heal rapidly. In the more severe reactions, the foci of endothelial destruction may be so numerous as to overlap, resulting in complete immunologic destruction of the entire endothelium. The dose-response relationships in this experimental system are discussed, as are its uses as a model for the study of the mechanism of endothelial damage during the course of specific corneal graft rejection.