Penetration of engineered antibody fragments into the eye.

Antibodies are powerful immunotherapeutic agents but their use for treating ocular disorders is limited by their poor penetration into the eye. We hypothesized that antibody fragments of relatively small size might penetrate the cornea more readily. Monovalent single chain variable region (scFv) antibody fragments and divalent miniantibodies were engineered from existing monoclonal antibodies, expressed in a bacterial expression system, and purified by metal ion affinity chromatography. Corneoscleral preparations from normal pig and cat eyes were mounted in a corneal perfusion chamber. Intact antibodies and antibody fragments were applied topically to the anterior corneal surface over 12-h periods, and samples were collected from the artificial anterior chamber. Similar experiments were performed with whole enucleated pig and human eyes. Penetration of antibodies and fragments was quantified by high-sensitivity flow cytometry on appropriate target cells. Both monovalent scFv and divalent miniantibody fragments (but not whole immunoglobulin molecules) passed through de-epithelialized and intact corneas after topical administration, and could be detected by antigen binding. Addition of 0.5% sodium caprate facilitated penetration through intact corneas. Topically-applied scFv was found to penetrate into the anterior chamber fluid of rabbit eyes in vivo. The engineered fragments were stable and resistant to ocular proteases. Monovalent and divalent antibody constructs of molecular weight 28 kD and 67 kD, respectively, can penetrate through intact corneas into the anterior chamber, with retention of appropriate antigen-binding activity. Such constructs may form novel therapeutic agents for topical ophthalmic use.

[Experience with 100 liver transplant recipients at the Rabin Medical Center and the Schneider Children's Medical Center].

Liver transplantation is the treatment of choice for end-stage liver disease. During the past 8 years we performed 102 liver transplants in 84 adults and 16 children. In the adults, 9 were combined transplants: 1 a liver-pancreas transplant for type I diabetes, and 8 liver-kidney transplants. In the children, transplants included 5 whole-livers, 5 left-lateral liver segments from living-related donors, 4 reduced-grafts of right or left lobes, and 2 split left-lateral segments. At a mean follow-up of 31 months (range 1-96) 70 were alive, 3 had died during surgery and 15 during the first postoperative months. Mortality was due to primary graft non-function (7), sepsis (10), intracranial hemorrhage (1), tumors (4), recurrent hepatitis B (2), biliary strictures (2) and chronic rejection (1). The 1- and 4-year survival rates were 79.5% and 69.6%, respectively. After transplantation, 10 developed biliary stricture (5 corrected by balloon dilatation) and 8 anastomotic stricture (7 corrected by surgery), and there were 2 multiple intrahepatic strictures. There was hepatic artery thrombosis in 5, including 4 children. In 3, grafts were salvaged by thrombectomy and 2 others underwent re-transplantation. In those who survived transplantation by more than 1-month, recurrent hepatitis B was seen in 6 of 17 (35%) and recurrent hepatitis C in 12 of 19 (63%). Thus, results of our first 100 liver transplants are similar to those reported by larger centers, showing that in an appropriate setting good results can be achieved by small transplant programs.

Glucocorticoids exacerbate insult-induced declines in metabolism in selectively vulnerable hippocampal cell fields.

Glucocorticoids (GCs), the adrenal steroids released during stress, can compromise the ability of hippocampal neurons to survive necrotic neurological insults. This GC-induced endangerment has energetic facets, in that it can be attenuated with energy supplementation. In the present report, we studied the effects of GCs on the metabolic response of specific hippocampal cell fields to necrotic insults. We used silicon microphysiometry, which allows indirect measurement of metabolism in real time in tissue explants. Aglycemia caused a significant decline in metabolism in dentate gyrus explants, but not in CA1 or CA3 explants. When coupled with our prior report of cyanide disrupting metabolism only in CA1 explants, and the glutamatergic excitotoxin kainic acid disrupting metabolism only in CA3 explants, this demonstrates that microphysiometry can detect the selective regional vulnerability that characterizes the hippocampal response to these necrotic insults. We then examined the effects of GCs on the response to these insults, monitoring explants taken from rats that were adrenalectomized, intact, or treated with corticosterone (the GC of rats) that produced circulating levels equivalent to those of major stressors. Increased exposure to GCs worsened the decline in metabolism in dentate gyrus explants induced by hypoglycemia, and in CA1 explants induced by cyanide (after eliminating the effects of glial release of lactate for the support of neuronal metabolism). Thus, GCs worsen the metabolic consequences of necrotic insults in hippocampal explants.

Glucocorticoids exacerbate the deleterious effects of gp120 in hippocampal and cortical explants.

Glucocorticoids (GCs), the adrenal steroids secreted during stress, can compromise the ability of hippocampal neurons to survive numerous necrotic insults. We have previously observed that GCs worsen the deleterious effects of gp120, the glycoprotein of the acquired immune deficiency syndrome virus, which can indirectly damage neurons and which is thought to play a role in the neuropathological features of human immunodeficiency virus infection. Specifically, GCs augment gp120-induced calcium mobilization, ATP depletion, decline in mitochondrial potential, and neurotoxicity in fetal monolayer cultures from a number of brain regions. In the present report, we demonstrate a similar gp120/GC synergy in adult hippocampal and cortical explants. We generated explants from rats that were either adrenalectomized, adrenally intact, or intact and treated with corticosterone to produce levels seen in response to major stressors. Metabolic rates in explants were then indirectly assessed with silicon microphysiometry, and cytosolic calcium concentrations were assessed with fura-2 fluorescent microscopy. We observed that basal levels of GCs tonically augment the disruptive effects of gp120 on metabolism in the CA1 cell field of the hippocampus and in the cortex. Moreover, raising GC concentrations into the stress range exacerbated the ability of gp120 to mobilize cytosolic calcium in a number of hippocampal cell fields. Finally, we observed that the synthetic GC prednisone had similarly exacerbating effects on gp120. Thus, GCs can worsen the deleterious effects of gp120 in a system that is more physiologically relevant than the fetal monolayer culture and in a region-specific manner.

Ultrafast semiconductor laser-diode-seeded Cr:LiSAF regenerative amplifier system.

An ultrafast, hybrid mode-locked semiconductor laser-diode system has been used to seed a flash-lamp-pumped Cr:LiSAF regenerative amplifier system, producing subpicosecond pulses with millijoule output pulse energy. This system has the potential to eliminate argon-ion-pumped-based, ultrafast laser systems.

Cyclosporin: poorly tolerated in familial Mediterranean fever.

Cyclosporin is poorly tolerated in patients with amyloidosis due to familial mediterranean fever who are receiving colchicine. There is a high incidence of gastrointestinal side-effects and muscle weakness, both of which are reversible on stopping cyclosporin. Thus in patients with amyloidosis secondary to familial mediterranean fever treated with colchicine, the use of cyclosporin as an immunosuppressive agent may be restricted.

Suppressor factor in plasma of aminophylline treated renal transplanted patients.

Eleven of 15 patients with a first acute rejection episode following cadaveric renal transplantation resumed adequate graft function and increased peripheral blood suppressor T-lymphocyte activity following treatment with 'pulse' methylprednisolone and aminophylline (1000mg orally daily for 14 days). Four of 11 patients treated with 'pulse' methylprednisolone alone resumed adequate graft function, but only two of these had elevated peripheral blood suppressor T-lymphocyte function. Nine of the 11 responding patients exhibited plasma suppressor activity to xenogenic graft versus host reaction but such activity was not observed in the plasma of any of the 11 patients who received methylprednisolone alone.