Amino acid composition of a neutrophil respiratory burst stimulant. Evidence for a protein, noncollagenous source

Activation of the neutrophil respiratory burst by the supernatant fraction from an alkali-treated collagen preparations (SAC) was enhanced by longer durations of exposure to alkali (1 N NaOH for 0.5-24 hr). The concentrate obtained from ultrafiltration (greater than 30,000 molecular weight) of SAC (1 N NaOH for 24 hr) retained the stimulatory factor. Fractionation of this ultraconcentrate by high-performance liquid chromatography showed that the stimulatory activity resided in the void volume (highest molecular weight). The amino acid composition of this active fraction revealed that this proteinaceous stimulant was not derived from the collagen molecule. Treatment of the SAC with ultrapure bacterial collagenase increased its stimulatory capacity, confirming its noncollagenous nature. Alkali treatment of whole cornea also released a similar large molecular weight, noncollagenous protein that stimulated the respiratory burst of polymorphonuclear leukocytes. Enhanced stimulation after prolonged NaOH treatment of the collagen preparation or collagenase treatment of SAC suggests that the stimulant might reside between collagen fibrils and then be released as the matrix is degraded.

The combined effect of citrate/ascorbate treatment in alkali-injured rabbit eyes

The incidence of ulceration and perforation in the cornea of alkali-injured eyes is significantly reduced by treatment with trisodium citrate or sodium ascorbate. Topical citrate reduces the inflammatory response in the cornea by inhibiting polymorphonuclear leukocytes. Topical ascorbate elevates the depressed level of this vitamin in the alkali-injured cornea, reversing a scorbutic condition. The purpose of the current study was to determine whether combined treatment with topical citrate and ascorbate has an additional therapeutic value when compared with citrate alone. Adsorbotear without EDTA was used as the vehicle for both medications. Rabbit eyes were injured with 1N NaOH for 35 s using a 12-mm well and were rinsed. Group I (47 eyes) received two drops of 10% citrate every hour on the hour and Adsorbotear on the half-hour for 14 h/day. Group II (48 eyes) received two drops of 10% citrate every hour on the hour and 10% ascorbate every hour on the half-hour for 14 h/day. The citrate/ascorbate group had significantly fewer ulcerations during the experiment than did the group receiving citrate alone (2 of 48 versus 10 of 47, 0.01 less than p less than 0.02). Both anterior ulcers in the citrate/ascorbate group and five ulcers in the citrate group healed to no ulcer by the end of the experiment (0 of 48 versus 5 of 47, 0.02 less than p less than 0.05). The average depth of ulceration was significantly less for the citrate/ascorbate group (p less than 0.001). No descemetoceles or perforations were observed in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

The intraocular changes of anterior segment necrosis

Anterior segment necrosis is an acute or chronic process occasioned by embarrassment of the blood supply of the anterior segment of the eye. In the acute form this vascular obstruction leads to severe corneal oedema, necrosis of anterior uvea, hypotony and cataract formation. Depression of aqueous humour formation accounts for severe reduction of glucose levels in corneal stroma and aqueous humour lasting for two days after cautery of the long posterior ciliary arteries (LPCA) in rabbits. Lactate levels are initially significantly elevated but return to normal after one week. Stromal hydration was elevated for one week but then returned to normal. Corneal epithelial glycogen was diminished at one and two days after surgery but then returned to normal. Although unproven, oxygen deprivation probably plays a major role in endothelial ischaemia and therefore corneal oedema. It is concluded that the abnormalities seen in anterior segment necrosis stem from changes in aqueous metabolic components resulting from severely reduced aqueous turnover. Hyperbaric oxygen and intracameral metabolite substitution are unproven treatments but merit further experimental study.

Sorption of sodium hydroxide by type I collagen and bovine corneas

There are no quantitative studies on the uptake of alkali into corneal tissues. To study this phenomenon, both type I collagen and bovine corneas were incubated in sodium hydroxide (NaOH) under varying conditions for periods up to 27.5 h. The sorption (absorption or adsorption) of the alkali to protein and tissue was measured as the quantity of NaOH no longer available for titration to neutrality with hydrochloric acid. Sorption was found to be dependent on the concentration of NaOH (0.01-1 N) but independent of the incubation temperature (4-35 degrees C). In whole cornea, sorption of 1 N NaOH began immediately and increased with time up to 6 h. After 6 h, sorption decreased, together with the observed degradation and solubilization of the tissue. Stripping of the corneal endothelium alone or of the endothelium and epithelium increased sorption in a similar manner when compared to whole corneas for periods up to 4 h. These observations are compatible with ionic and nonionic bonding of hydroxide ions to collagen (including that of the cornea) and the subsequent release of hydroxide ions during hydrolysis of the protein itself. Indirect evidence also suggests the inclusion of quantities of unbound hydroxide ions in hydrated gels of glycosaminoglycans. It is proposed that in a chemical burn of the cornea, alkali is both stored in the tissue (by sorption) and reacted with it (by hydrolysis), without any net consumption of alkali taking place.

Topical citrate inhibits the adherence of neutrophils to postcapillary venules

The high incidence of corneal ulceration in the alkali-injured rabbit eye can be reduced by topical citrate drops. Citrate interferes with polymorphonuclear leukocyte (PMN) accumulation in the corneal stroma after alkali injury. It inhibits the adherence, locomotion, respiratory burst, phagocytosis, and degranulation of human PMNs in vitro. The objective of this research was to determine if PMN adherence to the vascular endothelium could be inhibited by superfused citrate in vivo. PMN adherence to the endothelium of postcapillary venules in the hamster cheek pouch was greatly enhanced and maintained by addition of leukotriene B4 (LTB4) to the superfusate. Superfusion of the pouch with 24 mM citrate for 5 min, before addition of LTB4, inhibited PMN adherence to the endothelium. The free calcium level in the superfusate was reduced from approximately 650 to 33 microM in the presence of 24 mM citrate. When LTB4-augmented PMN adherence was allowed to occur, followed by citrate treatment (24 mM), it was reversed. Simultaneous addition of CaCl2 and MgCl2 to the superfusate raised the free Ca2+ level to 786 microM and reversed the citrate-induced inhibition of LTB4-augmented adherence. From this and other research, we conclude that citrate probably inhibits adherence of PMNs to pericorneal and conjunctival vessels in the eye, preventing their accumulation in the corneal stroma.

The efficacy of topical citrate after alkali injury is dependent on the period of time it is administered

The neutrophilic response in the alkali-injured rabbit cornea can be separated into two peaks: the first from 12-24 hr and the second at 21 days. In the experiments detailed here, alkali-injured rabbit eyes were treated for 0-7 days (early peak), 6-35 days (late peak), or 0-35 days (both peaks) with 6.5% or 10% topical citrate. Clinical evaluation of these eyes showed that treatment with 10% citrate (0-35 days) significantly reduced the incidence and severity of corneal ulceration from the control level. When 10% citrate was administered to block the early neutrophilic peak, the incidence of corneal ulceration was also significantly reduced (33.3% from 72.2%). The average ulcer depth increased gradually, reaching an intermediate level well below the control group by day 35. In contrast, 10% citrate treatment of the late peak had no significant effect on the incidence of ulceration; however, these ulcers were less severe than those in the control. When 6.5% topical citrate (0-35 days) was used, there was a significant reduction in the severity but not the incidence of ulceration. In addition, the beneficial effects obtained from separate treatment of the early and late PMN peaks were mostly lost. These experiments suggest that both the early and late peak of the PMN response after alkali injury are important to the development of corneal ulcers. We hypothesize that the early use of 10% citrate diminishes the initial peak of PMNs, interfering with the release of self-perpetuating inflammatory mediators, thereby decreasing the later accumulation of PMNs that cause ulceration.

Citrate or ascorbate/citrate treatment of established corneal ulcers in the alkali-injured rabbit eye

Immediate treatment of alkali-injured eyes with citrate or ascorbate has previously been shown to prevent corneal ulceration and perforation in the rabbit. Other experiments showed that while ascorbate treatment of established ulcers did not appear to lead to significant healing it did reduce perforations by prolonging the presence of descemetoceles. In the present experiment with established ulcers, alkali injuries were created with 1 N NaOH in a 12 mm corneal well for 35 seconds. Eyes were entered into the study with anterior, middle or posterior ulcers. When compared to controls, 10% citrate (q1/2 hr) significantly reduced the deepening of anterior stromal ulcers while 10% ascorbate/10% citrate (q1 hr/q1 hr-30 min apart) showed only a trend toward reduction of these ulcers (14 hr of dropping). The demonstration of healing (total vascularization or no ulcer) is significant when comparing the control group (8.3%) to the citrate treated group (58.3%, 0.01 less than P less than 0.009), but not the ascorbate/citrate group (18.2%). Sixty-seven percent of anterior stromal ulcers in the control group progressed to descemetocele or perforation, compared to 8.3% in the citrate treated (0.003 less than P less than 0.004), and 45.5% in the ascorbate/citrate treated group (not significant). While the numbers of ulcers entered as middle stromal were too few to analyze statistically, the reduced numbers of perforations and increased stability prior to perforation in both treatment groups suggest a positive effect by both citrate and ascorbate/citrate. Treatment of posterior stromal ulcers did not prevent the development of descemetoceles and perforations in either treatment group; however, the numbers in this category were too few to analyze.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of citrate on the adherence of neutrophils to nylon fibers in vitro

The therapeutic effect of citrate on alkali-burned eyes is thought to be the result of inhibition of PMN activities while ascorbate apparently stimulates the production of new collagen by scorbutic fibroblasts. Attachment of PMNs to the vascular endothelium is the initial PMN response to mediators and must occur before diapedesis and chemotaxis can produce a tissue infiltrate. The present study was undertaken to test the effects of citrate or ascorbate on the in vitro adherence of resting and leukotriene B4 (LTB4)-treated PMNs. Citrate preincubation of resting or LTB4-treated PMNs inhibited adherence in a dose-dependent manner. Inhibition of LTB4 augmented adherence by 12 mM citrate was effectively reversed by the addition of Ca2+ and Mg2+ (6 mM each). Ascorbate had no significant effect on the adherence of resting or LTB4 treated PMNs. In addition we wished to test the effectiveness of the breakdown product(s) from alkali burned collagen (Type 1) as an augmentor of adherence because of its effectiveness as a locomotory and respiratory burst stimulant. These break-down product(s) had no effect on the adherence of resting or LTB4-treated PMNs unless bovine serum albumin (BSA) was omitted from the incubation mixture. In the absence of BSA, these breakdown products inhibited both types of adherence in a dose-dependent manner with dilutions from 1:10 to 1:1000. This inhibition is probably not clinically meaningful since PMN adherence takes place in the vasculature where BSA would always be present. As a consequence of citrate inhibition of adherence in vivo, PMNs would be denied access to the injury site, trapping them in a resting state within the circulatory system.

Preliminary characterization of a polymorphonuclear leukocyte stimulant isolated from alkali-treated collagen

This study reports the preliminary characterization of a stimulant released from alkali-treated collagen which activates the respiratory burst of PMNs. The supernatant fraction from alkali-treated collagen (SATC) was precipitated with ammonium sulfate, resuspended, and centrifuged through a sucrose gradient (10-30%, W/V). Proteins were detected throughout the gradient but PMN stimulatory activity was found mainly in fractions 1 and 2 (bottom of gradient), indicating a very high molecular weight. When SATC was layered on a denser sucrose gradient (20-85%, W/V), protein was spread over the upper half of the gradient. The peak of PMN stimulatory activity was found in the middle of the gradient (fractions 8 and 9), indicating a molecular weight similar to the 200,000 dalton standard. High pressure liquid chromatography (HPLC) of fractions from this heavier sucrose gradient showed a small peak, followed by a much higher main peak. The small peak, with the highest molecular weight peptide, is responsible for stimulation of the respiratory burst of PMNs (fraction 8 and 9). The source of this stimulant is yet to be determined.

Alkali-burned collagen produces a locomotory and metabolic stimulant to neutrophils

Polymorphonuclear leukocytes (PMNs) invade the cornea following an alkali burn apparently undergoing a respiratory burst and degranulation, which is thought to lead to corneal ulceration. The supernatant obtained from burned Sigma collagen (Miller type 1) or from bovine cornea produced a significant locomotory stimulus to PMNs. Citrate inhibited this locomotory stimulus by 69.5% and 98%, respectively. PMNs were stimulated to undergo a respiratory burst without the concomitant release of beta-glucuronidase when exposed to the supernatant from alkali-burned commercial collagens, or from bovine or porcine corneas. This stimulation is reduced by 72% (Sigma collagen) or 89% (bovine cornea) when the supernatant is dialyzed against distilled water and reinstated when the osmolality is increased. The degree of the respiratory burst is partially dependent on the volume of the supernatant, the duration of alkali exposure, and/or the concentration of NaOH used. The respiratory burst of PMNs stimulated by alkali-burned Sigma collagen supernatant is inhibited by trifluoperazine but not by citrate or EDTA. Light and electron microscopy of these stimulated PMNs show many large blebs and hairlike projections. The authors hypothesize that collagen breakdown product(s) from alkali burning might be the initial, or one of the initial stimuli, for PMN invasion into the cornea and the subsequent activation of the respiratory burst.

Evaluating the undescended testis

This problem is often associated with other anomalies which, if present, are usually evident on the initial examination. Therapy before age two is mandatory to preserve fertility. The malignant potential of undescended testes is well established. Placement of the testes into the scrotum facilitates frequent examinations. All postpubertal patients with intra-abdominal testes, as well as patients who have inguinal testes and are between puberty and age 50, should be referred for orchiectomy.

Urethral duplication and complete bladder exstrophy

Urethral duplication is a rare anomaly that has been classified into epispadiac, hypospadiac, spindle, Y-duplications and collateral varieties. We report a case of an accessory urethra associated with complete bladder exstrophy in which the accessory urethra was integrated into the epispadias repair. To our knowledge this is the first case reported of urethral duplication associated with bladder exstrophy.

Polymorphonuclear leukocytic inhibition by citrate, other metal chelators, and trifluoperazine. Evidence to support calcium binding protein involvement

Corneal ulceration after severe alkali burns of the eye is thought to result principally from collagen breakdown as a consequence of local polymorphonuclear leukocyte (PMN) activities. The favorable effect of topical citrate on such burns suggested a direct effect on these inflammatory cells. These in vitro studies show that the stimulation of human PMN by opsonized zymosan can be inhibited by citrate, EDTA, and EGTA. These compounds interfere with opsonized zymosan attachment to PMN, preventing the respiratory burst, phagocytosis, and degranulation. Reversal of this inhibition by calcium and/or magnesium suggests that mechanism is calcium chelation. Trifluoperazine (TFP) inhibition of opsonized zymosan attachment and phagocytosis implicates the involvement of calmodulin. We propose that citrate, EDTA, and EGTA interfere with the receptor mediated attachment of opsonized zymosan to the PMN cell membrane, leaving the PMN in a resting, granulated state. Inhibition of the receptor system by calcium depletion may be the result of interference with calcium-calmodulin modulated microfilament and/or microtubule interfaces in the PMN plasma membrane. It is postulated that comparable events occur in the citrate treated alkali burned cornea. Citrate inhibition of PMN may be useful in other eye and systemic diseases.

Stage D1 adenocarcinoma of prostate

The natural history of Stage D1 adenocarcinoma of the prostate remains unclear. In a series of 50 patients with positive pelvic lymph nodes at the time of staging lymphadenectomy, metastatic disease developed in 43 per cent of the patients treated for cure within the period of time of follow-up. Several series from the literature confirm those findings. Positive pelvic lymph nodes most probably represent systemic disease, and the patients are incurable by current surgical and radiotherapeutic modalities.

Acid phosphatase: its influence on the management of carcinoma of the prostate

Of 343 patients who underwent pelvic lymph node dissection during treatment for carcinoma of the prostate 25 had persistently elevated serum enzymatic acid phosphatase levels preoperatively: 15 (60 per cent) had metastases to the pelvic lymph nodes and 10 (40 per cent) had negative nodes. Bone metastases occurred in 10 of 12 (83 per cent) and 5 of 7 patients (71 per cent), respectively, who were followed for a minimum of 2 years. Of the 318 patients with normal serum enzymatic phosphatase levels 70 (22 per cent) had positive nodes. A persistently elevated serum enzymatic acid phosphatase level in patients with proved carcinoma of the prostate, with elimination of infrequent causes of enzyme elevation, indicates metastases and has significant implications regarding staging and, thus, therapy of this disease.

The effects of citrate on fMLP-induced polymorphonuclear leukocyte stimulation and locomotion

Citrate reduces the incidence of corneal ulceration and perforation in alkali burned eyes and prevents polymorphonuclear leukocyte (PMN) accumulation in certain inflamed ocular tissues. Chelation of Ca2+ and Mg2+ by citrate appears to be the mechanism causing strong inhibition of in vitro PMN stimulation by opsonized zymosan. It is important to know if other activating agents of PMNs, with differing sensitivity to divalent cations, are inhibited by citrate. Citrate (12 mM) partially inhibits fMLP stimulation of the respiratory burst (50%) and degranulation (65%) of PMNs in a divalent cation free media, while having no effect or only a small effect in the presence of 1 mm Ca2+. Citrate also caused significant inhibition of fMLP (12 mM = 50%) induced locomotion of PMN when incubated in media containing 500 microM Ca2+ and 600 microM Mg2+ in a modified Boyden chamber. When used together, Ca2+ (6 mM) and Mg2+ (6 mM) reduced this inhibition to only 20%. Citrate apparently inhibits fMLP-induced stimulation in cation free media by chelating CA2+ effluxed from intracellular storage sites. In the chemotactic studies, citrate probably chelates extracellular Ca2+ and Mg2+. The divalent cation requirements of the activating agents and/or the PMN function may determine the degree of inhibition by citrate. It is therefore important to identify the mediators in alkali burned corneas as well as other inflammatory conditions.

Chemical injuries of the eye

This overview of the biochemical and pathophysiologic events after chemical burns of the eye is intended to act as a guide for appropriate therapy. Effective emergency measures must be instituted immediately followed by careful clinical evaluation to recognize and then treat problems at their inception. When and how to use the variety of drugs and devices is detailed. When these new methods and technology are applied successfully the clinical course may be improved and visual rehabilitation secured. The early results of conjunctival transplantation and hormonal therapy offer promise from experimental procedures. Exciting new treatments employing the foodstuffs ascorbate or citrate (orthomolecular therapy) are currently under investigation. The National Eye Institute sponsors our ongoing randomized clinical trial of these compounds in the treatment of the alkali burned eye. The outcome may change our thinking and our expectations after chemical burns of the eye.

Aphakic refractive penetrating keratoplasty using newborn donor corneas. A preliminary report on an alternative approach to refractive correction

Eyes with corneal disease receiving transplants from premature, full gestational newborns or postnatal donors yield refractive results with a myopic shift. When the donor cornea is from a newborn (40-41 week gestation) this myopic shift was sufficient to correct 5 of 7 aphakic eyes to an average postsurgical refraction of -1.0 diopter (spher equiv). One premature cornea gave -6.0 diopters while six postnatal infant corneas gave an average correction of +8.6 diopters (spher equiv). The steep corneal curvature resulting from surgery explains the additional refractive power noted. The surgical difficulties encountered and the unknown long-term results auger for a slow and controlled introduction of this concept into our everyday practices.

The effects of chemical injury on the ocular surface

Chemical burns of the eye may destroy all of the corneal epithelium and large portions of conjunctival epithelium into the fornices. Restoration of the ocular surface after a chemical burn depends on the centritedal movement of conjunctival epithelial cells and their adherence to the altered corneal stroma. Epithelial movement after a corneal burn is normal for 72 hours after a burn, but persistent epithelial defects thereafter commonly are not resolved until total corneal vascularization occurs. Although this fresh epithelium may be protected by a bandage soft contact lens, more promising and far-reaching approaches may follow epithelial supplementation and even replacement. The link between the health and integrity of the epithelial layer as it relates to the corneal substratum and its cellular constituents remains to be forged.

Effects of topical 10% ascorbate solution on established corneal ulcers after severe alkali burns

When established corneal ulcers induced by alkali burning were treated with 10% ascorbate drops, no perforation occurred, in contrast to a 25% incidence in the control group. If perforations and descemetoceles were grouped together, these difference became insignificant (i.e., 14.2% ascorbate-treated vs. 25% control). Prolongation of descemetocele presence without perforation in the ascorbate-treated group indicated some therapeutic effect. We conclude that topical ascorbate does not substantially alter the outcome of established corneal ulcers.

Sodium citrate reduces the incidence of corneal ulcerations and perforations in extreme alkali-burned eyes--acetylcysteine and ascorbate have no favorable effect

Alkali-burned eyes (45 sec, 12 mm, 4N NaOH) were subjected to topical treatment with 10% ascorbate, 20% acetylcysteine, 10% ascorbate together with 20% acetylcysteine, 10% citrate, or Adsorbotear vehicle. Only citrate-treated eyes showed a significant decrease in corneal ulcerations and perforations (17%) compared with ascorbate (88%), acetylcysteine (81%), ascorbate/acetyl-cysteine (100%), or Adsorbotear (75%). In the citrate-treated eyes there was a significantly reduced incidence of band keratopathy (17%) but an increased incidence of hyphema (100%). Both groups receiving acetylcysteine developed acellular corneal caps, the result of peripheral ulceration undermining the central cornea. Polymorphonuclear neutrophils (PMN) were substantially increased at the base of the cap in the acetylcysteine- and acetylcysteine/ascorbate-treated eyes at day 56. At the end of the experiment, citrate-treated eyes showed substantially fewer stromal PMN than any other group. These results show that topical citrate has a most favorable effect on the incidence of corneal ulceration and perforation after alkali burning.

The influence of parenteral ascorbate on the strength of corneal wounds

Rabbits receiving subcutaneous ascorbate after corneal wounding showed significant elevation of aqueous humor ascorbate levels but no enhancement of wound breaking strength when compared to controls. In a second group of rabbits, perilimbal alkali burning reduced aqueous humor ascorbate levels one-half to one-third normal. In these perilimbally burned eyes with wounds in clear cornea, subcutaneous ascorbate significantly raised the aqueous humor ascorbate level and enhanced breaking wound strength compared to controls. We conclude that parenterally administered ascorbate has no salutory effect on the breaking strength of corneal wounds in the normal rabbit eye. In contrast, subcutaneous ascorbate has a very favorable effect on the breaking strengths of corneal wounds in those eye with depressed aqueous humor ascorbate.