Transcellular transport and membrane insertion of the C5b-9 membrane attack complex of complement by glomerular epithelial cells in experimental membranous nephropathy

Deposition of the C5b-9 complex of C in glomeruli of rats with experimental membranous nephropathy (MN) is essential for the development of proteinuria. In this investigation C5b-9 was localized in the passive Heymann nephritis (PHN) by immunoelectron microscopy with a mAb specific for C5b-9(m) neoantigen. Its distribution was compared with that in another model of MN induced by successive injections of cationic human IgG and rabbit anti-human IgG into rats. In PHN C5b-9 was found: 1) in the immune deposits (ID), and on the cell membranes of foot processes close to the ID; 2) in clathrin-coated pits of the glomerular epithelial cells (GEC) close to the ID and in membrane vesicles in the cytoplasm, separated from sheep IgG and the gp330 Ag; 3) in high concentration in multivesicular bodies of GEC; and 4) in association with membrane vesicles in the urinary space which presumably are the exocytosed content of membrane vesicular bodies. By contrast, in the cationic IgG-MN model C5b-9 was found mostly in ID, but rarely within the GEC. By freeze-fracture electron microscopy we have further identified 200- to 250-A intramembrane particles in PHN in the cell membranes of the "soles" of the foot processes which resemble membrane inserted human C5b-9(m). Degradation products of C5b-9 were further detected by immunoblotting of a 100,000 x g pellet of PHN rat urine. These results indicate that, in PHN, C5b-9 is inserted into the cell membranes of GEC, and that it is selectively endocytosed and transported across GEC by a cellular mechanism which apparently protects the cell from accumulation of membrane-inserted C5b-9.

A beta 1-integrin receptor for fibronectin in human kidney glomeruli

The fibronectin receptor (FNR) is a transmembrane heterodimeric glycoprotein which shares a common beta 1-chain with several other members of the integrin family of adhesion receptors. The authors have prepared a membrane fraction of isolated human glomeruli, from which two proteins (apparent molecular weights 120 kd and 140 kd) bound to a fibronectin-column, and were selectively released by the synthetic peptide Arg-Gly-Asp-Ser. These molecules were labeled in immune overlays by an antibody raised against the FNR from human placenta that recognizes both the FNR-specific a-chain and the group-specific beta 1-integrin chain. In sections of normal human kidneys this antibody labeled predominately the mesangia and the peripheral capillary walls of glomeruli by an immunoperoxidase procedure. Quantitative immunoelectron microscopy, using an indirect immunogold procedure, revealed a preferential localization along the cell membranes of mesangial, epithelial, and endothelial cells that face the mesangial matrix or the glomerular basement membrane (GBM). In kidney biopsies from patients with various glomerular diseases (membranous and other forms of glomerulonephritis, minimal change disease) the distribution was similar to that in normal glomeruli. These findings indicate that a beta 1-integrin-related FNR is present in normal and diseased human glomeruli.

Does vitrectomy followed by intraocular gas tamponade offer sufficiently effective treatment of retinal detachment due to holes in the posterior pole?

We report on 17 consecutive cases of retinal detachment due to macular hole surgically treated by one of the authors (S.B.) between the fall of 1982 and 1985. The standard method used was pars plana vitrectomy and intraocular air tamponade. In cases of subsequent reaccumulation of subretinal fluid, the macular hole was cautiously coagulated. With repeated redetachment and as a last resort, silicone oil was injected into the vitreous cavity. After a follow-up period ranging from 5 to 42 months, 13 of the 17 eyes were cured; in 2 aphakic eyes treatment remained unsuccessful; in 2 eyes a small central detachment with some accumulation of subretinal fluid persisted but did not progress. Vitrectomy and gas tamponade alone, without coagulation, constitute the safest and most sparing treatment of this type of retinal detachment. Unfortunately, approximately one half of these cases require subsequent additional photocoagulation because of renewed accumulation of subretinal fluid. In about one fourth of macular hole retinal detachments, however, lasting reattachment is achieved only by silicone oil tamponade following initial vitrectomy and air/gas tamponade.

Identification of a 400-kd protein in the brush borders of human kidney tubules that is similar to gp330, the nephritogenic antigen of rat Heymann nephritis

The nephritogenic antigen of Heymann nephritis (HN)--a well-studied experimental rat model disease of human membranous glomerulonephritis (MGN)--was recently shown to be a 330-kd glycoprotein (gp330) which is present in the membranes of both the rat tubular brush borders and of podocytes. Because the pathogenic antigen(s) of MGN are unknown, the authors have searched for a gp330-like molecule in human kidney and for its role in MGN. The authors here report that a membrane protein (apparent molecular weight 400 kd) is present in human kidney which is immunologically cross-reactive with rat gp330. By immunoelectron microscopy (using rabbit anti-rat gp330 IgG or a monoclonal anti-400-kd IgG) this molecule is similarly localized in human proximal tubules, but it is absent from the podocytes of human glomeruli. The 400-kd molecule is not detected in the glomerular immune deposits of 30 biopsies of MGN. It is proposed that this is due to the lack of the 400-kd protein in human glomeruli which prevents the formation of initial 400-kd anti-400-kd IgG immune complexes in situ.

The role of the epidemiologist in natural disasters

Natural disasters continue to be a major cause of morbidity and mortality. Natural disaster epidemiology has led not only to the scientific measurement and description of disaster-associated health effects, but also to strategies for preventing adverse health consequences and improving post-impact health care delivery. Results of epidemiologic studies of natural disasters provide clues to diagnosis, help medical care providers match resources to needs, and permit better contingency planning. Well-documented medical records are an essential resource for disaster epidemiologists. Cooperation between health care personnel and epidemiologists can help lessen the public health impacts of natural disasters.

[Sulbactam and clavulanic acid: studies of enzyme kinetics and synergism with ampicillin and mezlocillin]

Both inhibitors clavulanic acid and sulbactam exhibit high affinity (Ki-values less than 10(-6) mol/l) to the beta-lactamases of gram-negative bacteria with predominant penicillinase activity and lowered affinity to enzymes with cephalosporinase activity (above all clavulanic acid). As compared to sulbactam there was a stronger synergism of clavulanic acid with ampicillin or mezlocillin in those isolates producing either a plasmid-mediated or a chromosomally-mediated penicillinase. In beta-lactamase-overproducing Klebsiella ssp. variants both inhibitors could protect neither ampicillin nor mezlocillin from breakdown-independent of the synergy observed in the corresponding wild-type strains. Moreover, there was a marked synergism between mezlocillin (but not ampicillin) and sulbactam in beta-lactamase-overproducing Enterobacter cloacae variants. There was no strong relation between the amount of enzyme produced and the resulting synergy between inhibitor and antibiotic among clinical isolates. These observations agree with the results obtained for routinely performed susceptibility testing of amoxycillin/clavulanic acid and ampicillin/sulbactam.

High-energy electrons used to inhibit experimental intraocular proliferation and detachment

Irradiation of rabbit eyes with high-energy electrons was used to test the inhibition of experimental intraocular proliferation and retinal detachment, produced by intravitreal implantation of 250,000 homologous fibroblasts. After irradiation with 2,000 rad, started 5 days after implantation, 45% of eyes (9 of 20) still manifested traction detachment. When the dose was increased to 3,000 rad and radiation treatment was started 1 day after implantation, proliferation and traction detachment were observed in only 10% of eyes (2 of 20). No acute damage to retinal tissue or nerve fibers was observed. Because it is easily available, simple in application and dose adjustment, and without toxic side effects, radiation therapy should be considered as an effective alternative to drug treatment for the inhibition of intraocular proliferation and detachment. Statistically significant results of this investigation suggest its use combined with surgery in certain reproliferative cases in man.

Estimating soil ingestion: the use of tracer elements in estimating the amount of soil ingested by young children

In this pilot study, we modified methods used in estimating the amount of soil ingested by ruminants to measure soil ingested by children. Using aluminum, silicon, and titanium as tracers, we estimated soil ingestion for 59 children aged 1-3 yr from East Helena, Montana. Estimated daily soil ingestion based on aluminum and silicon concentrations were 181 and 184 mg/day, respectively, whereas the estimate based on the titanium concentration was about 10 times higher, 1,834 mg/day. Although we do not consider these estimates accurate measures of soil ingestion, the method we used is a reasonable approach that, to our knowledge, has not been used before in humans. However, our estimates will be revised as refinement of this method and better understanding of the metabolism of aluminum, silicon, and titanium lead to more accurate data for analysis.

[Differential diagnosis of papilledema]

Terminology, pathogenesis and differential diagnosis of papilloedema are discussed. A series of 100 consecutive patients with optic disc swelling is reviewed. Increased intracerebral pressure accounted for 32% of the cases. Vascular disease, such as central vein occlusion, central arterial occlusion and ischaemic neuropathy were the underlying diagnoses in the second largest group (22%) and in 18% of cases inflammatory disease caused the papillitis.

Repair of retinal detachments with temporary balloon buckling

Between 1982 and 1984, the temporary balloon buckle, as described by Lincoff and Kreissig in 1978, was successfully used in 52 eyes. The indications were retinal detachments with only one break or with closely grouped breaks together not exceeding one clock hour of the fundus. No consideration was given to the duration and extent of retinal detachment and macular involvement, or to the degree of myopia and recent vitreous hemorrhage. Excluded were cases with incipient proliferative vitreoretinopathy. The operation was successful in 50 of the 52 eyes. It was unsuccessful in one eye, in which, despite several subsequent conventional interventions, proliferative vitreoretinopathy developed, and in a second eye, in which a circumscribed retinal elevation around a large flap tear persists. In 17% of cases (9 of 52 eyes) fresh retinal defects were discovered 1 week to 6 months postoperatively. All were successfully treated with laser therapy. As a result, we consider temporary balloon buckling a simple and curative technique for a selected group of patients presenting retinal detachments.

[Posterior chamber lens implantation after removal of an intralens metallic foreign body]

This paper presents a case report of posterior chamber lens implantation after a perforating eye injury. We failed to extract the foreign body with a hand magnet and to close the capsule wound by application of a fibrin tissue adhesive. The posterior capsule was intact, and hence we performed an extracapsular cataract extraction with implantation of a posterior chamber lens. The foreign body was expressed together with the nucleus. The functional result is satisfactory.

[Advantages of sliced silicone sponge in retinal detachment surgery]

A retrospective study was undertaken in order to compare full-thickness sponge with sliced sponge in retinal reattachment operations. In 41 patients (42 eyes) in whom a sliced plug was used, retinal reattachment was achieved in all cases; there were no infections, but lesions of the conjunctiva could not be prevented. In the control group with conventional full-thickness sponge, retinal reattachment was not achieved in 2 out of 28 cases, and in 2 eyes infection occurred, resulting in rejection of the plug. The authors conclude that the results of retinal reattachment surgery are the same with sliced sponge plugs as with full-thickness plugs. The advantages offered by the elastic effect of sliced sponge are reduced danger of rejection, less irritation of the eye and improved patient comfort. Scleral buckles after plugging with sliced sponge are smoother and broader and episcleral support of the retinal defect is adequate.

Inhibition of experimental intraocular proliferation with intravitreous 5-fluouracil. A transmission electron-microscopic study in rabbits

5-Fluouracil, administered at concentrations of 1 and 5 mg to inhibit experimental intraocular proliferation produced by intravitreously implanted fibroblasts in rabbits, produced tissue alterations revealed by TEM. The degranulation and migration of pigment epithelial cells, the incipient degradation of axons and myelin sheets, the migration of glial cells and the prominent edema of the inner layers indicated a non-negligible damage to the retina, suggesting to abstain from its use in human eyes and to search for less neurotoxic drugs, possessing the same inhibitory effect on intraocular proliferation.

Inhibition of experimental intraocular proliferation with intravitreal 5-fluouracil

5-Fluorouracil was used to inhibit experimental intraocular proliferation in rabbit eyes, produced by homologe fibroblast implantation. Two different concentrations were used, 1 and 5 mg in a single intravitreal injection. The eyes were followed up over 4 weeks. Proliferation and resulting traction detachment was reduced from 75% to 30% in the 1-mg 5-fluouracil group. In addition, we observed retinal and vascular changes in a considerable number of eyes treated with 1 mg and much more pronounced alterations in most of the eyes treated with 5 mg fluouracil.

The value of the edrophonium tonography in the diagnosis of myasthenia gravis

Tonography of the eye was performed after administration of 10 mg edrophonium chloride (Tensilon) in 13 patients with clinically diagnosed myasthenia gravis. In ten of these patients repetitive nerve stimulation was used to examine the function of the motor end-plate. A significant pressure rise (more than 2 mm Hg) within the 1st min after edrophonium administration was observed in three patients (four eyes), whereas eight of the ten patients who underwent nerve stimulation showed positive results. The edrophonium tonogram test does not seem to be significant enough to define the diagnosis in early myasthenia gravis. Beyond this, these tests might have lost some of their value due to the introduction of antibody analysis against acetylcholine receptors, which serve as a very sensitive diagnostic tool now.

[Vitrectomy in inflammatory diseases of the posterior segment of the eye]

Eight patients with chronic endogenous uveitis, chorioretinitis, toxoplasmosis and infective endophthalmitis underwent pars plana vitrectomy mainly to improve vision by clearing the media or removing membranes. Beyond this it turned out that in eyes with chronic endogenous uveitis vitrectomy might also alter or diminish the severity as well as the frequency of attacks. The role of the vitreous as an autoimmune agent is discussed.

Advances in intraocular techniques in the treatment of retinal detachments arising from holes of the posterior pole

Two groups of retinal detachments arising from macular holes were compared. The first group consisted of 27 consecutive cases operated upon during the years 1972-7 by various techniques (encircling and hemi-encircling procedures, scleral resection, scleral pocket, and silver clip). The second group consisted of 18 consecutive cases operated upon in the years 1978-81 by pars plana vitrectomy to release vitreous traction or make intraocular manoeuvres possible. In all cases of the second group an intraocular gas bubble was used to tamponade the macular hole, and the hole was coagulated only if necessary. There was not only a significantly better anatomical result in the second group, but the functional results were more favourable. Two-thirds of the eyes of the second group reached a visual acuity between 6/12 and 6/48, while in the first group none of the eyes gained a better vision than 6/60. The reading vision in 2/3 of the first group was negligible, while nearly half of the cases in the second group reached useful acuity between Jaeger 3 and 10.

[Value of echography for diagnosis and follow-up of perforating eye injuries]

The introduction of vitreous surgery with its multiple capabilities of intraocular manipulations makes it possible to operate on cases which had been considered as hopeless up to now. With these techniques the importance of ultrasonic examination increased especially in cases with severe perforating injuries and their follow-up, to detect the onset of intravitreal fibrosis and early traction detachment, when no fundus view is possible. An other indication for ultrasonic examination is the exact localization of foreign bodies. Out of 484 perforating injuries which were examined and treated in our clinic during the last 10 years, ultrasonographic diagnosis was helpful in 18% and had further therapeutic consequences: In 24% a detachment operation or vitreous surgery was necessary, in 30% ultrasonography showed severe damage and surgery was considered to be ineffective. 42% were follow-up examinations of the posterior segment.

[Preliminary results with the Lincoff-Kreissig balloon buckle]

The authors used the unsecured balloon buckle of Lincoff and Kreissig in 15 cases during a six-month period (September 1981 to March 1982) at the Ist Eye Clinic in Vienna and the Eye Department in Salzburg. Cases were selected in which one large tear and a circumscribed detachment existed, as well as detachments with only one tear or a group of holes which did not exceed one hour in extent. After an observation period of between three and nine months the detachment was cured with the balloon buckle in 12 eyes, while in three eyes it failed; in two of them a cure was achieved by permanent buckle operation. In one eye the find result was MPP. This method seems particularly suited to cases where cryocoagulation or photocoagulation alone is too dangerous, but on the other hand a permanent buckle operation might cause muscle disturbances and irritating diplopia in eyes with usually good visual acuity before and after surgery. Further experience with the unsecured balloon buckle will show how far the indications for this method can be extended.

[Corneal sensitivity in diabetes mellitus]

We measured corneal sensitivity in 30 eyes of juvenile and 70 eyes of maturity onset diabetics by means of the esthesiometer developed by Draeger. We found a significant decrease in corneal sensitivity in both juvenile and maturity-onset diabetics with a positive correlation between the decrease of corneal sensitivity and duration of symptoms in juvenile diabetics. In addition, the decrease in corneal sensitivity was more marked in diabetics with insufficient blood sugar control. Only 43% of diabetics with fundal changes had a concomitant decrease in corneal sensitivity. Diabetic retinopathy therefore seems to precede a polyneuropathy demonstrable by measurements of corneal sensitivity.

Corneal sensitivity during the menstrual cycle

Corneal sensitivity was determined in 5 women with regular menstrual cycles by means of a new aesthesiometer developed by Dräger. Throughout one menstrual cycle we measured corneal touch thresholds (CTT) daily and did serial determinations of urinary luteinising hormone and pregnanediol levels. CTT rose in 4 women with proved ovulation in the days before or on the day of ovulation, while corneal sensitivity remained unchanged in one anovulatory subject. We observed no changes in CTT prior to menstruation. The decrease in corneal sensitivity might be related to the preovulatory oestrogen peak.