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Nitrofurantoin not surface active agent in rabbit urinary bladder
NITROFURANTOIN
NOT SURFACE ACTIVE AGENT
IN RABBIT URINARY BLADDER* MICHAEL PHILIP ROBERT
R. RUGGIERI,
PH.D.
M. HANNO, M.D. M. LEVIN,
PH.D.
From the Division of Urology, University of Pennsylvania School of Medicine, and Veterans Administration Medical Center, Philadelphia, Pennsylvania
ABSTRACT-It has been recently suggested that nitrofurantoin may induce symptoms of interstitial cystitis by acting as a surface active agent that destroys glycosaminoglycan (GAG) on the bladder surface. Evidence accumulated over the past decade has demonstrated that the bladder surface GAG prevents bacterial adherence. In this experiment, exposure of the bladder lumen to nitrofurantoin at more than twice the therapeutic concentration did not destroy the bladder GAG layer (as evidenced by periodic acid-Schiff histochemistry) nor increase bacterial adherence as did a true surface active agent (Triton X-100). Acid treatment as well as all tested organic solvents except 50 % dimethyl sulfoxide (DMSO) also removed the bladder GAG layer and increased bacterial adherence. These results indicate that neither nitrofurantoin nor 50 % DMSO has adverse effects on the bladder surface and thus is unlikely to initiate the interstitial cystitis symptom complex by means of surfactant activity.
There have been several reports in the recent literature, particularly in the lay news media, suggesting that antibacterial therapy may sometimes induce interstitial cystitis in certain patients. 1,2 It has been suggested that one antibacterial agent in particular, nitrofurantoin, acts as a surface active agent (surfactant) destroying the glycosaminoglycan layer lining the bladder luminal sm-face.3 Experimental work in our laboratory and others over the past several years has demonstrated that the mucin layer lining the bladder luminal epithelium prevents bacterial adherence. Removing this mucin layer with an acid rinse leads to increased bacterial adherencea4m7 Exposing this mucin-deficient bladder to either exogenous glycosaminoglycans-12 or to a solution of blad*Supported in part by grants from Veterans Administration, NIH Grant RO-I-AM 6508-01, and the McCabe Fund.
534
der mucosal extract from a different species13 restores bacterial adherence to the low levels of the mucin-intact state. We investigated the effect of nitrofurantoin at more than double the therapeutic concentration on the periodic acid-Schiff (PAS) staining and functional antiadherence integrity of the bladder luminal surface. In addition, a true surfactant (Triton X-100) and organic solvents were also tested to determine if they could remove the mucin layer as evidenced by PAS histochemistry and increased bacterial adherence. Material and Methods Preparation of bacteria Lyophylized bacterial neotype Escherichia coli 11775 (purchased from the American Type Culture Collection, Bethesda, Maryland) were rehydrated in sterile 0.9 % NaCl and serially
UROLOGY
i
MAY 1987
/
VOLUME XXIX, NUMBER 5
EFFECT
passed repeatedly in static brain-heart infusion broth (BHI; Difco Laboratories, Detroit, Michigan) at 37°C. To label the organisms with 3H, a 0.4 % inoculum (v/v) was added to 4 ml of fresh BHI containing 5 PCi 3H-Adenine/ml (New England Nuclear, Boston, Massachusetts) and incubated statically at 37°C for eighteen to twenty-four hours. The bacteria were sedimented at 3,000 x g for twenty minutes and resuspended in their original volume of 0.9 % NaCl. Colony-forming units (CFU) were determined by serial dilution as previously described.11J3 Bacterial suspensions were prepared for a given experiment with an optical density adjusted to 0.2 U to yield a constant lOa CFUlml suspension, Mu&a-deficient
rabbit
bladder
of radioactivity
Bladder mucosae were digested overnight in 1 ml of 1 .O N NaOH at 37°C. The volume was then brought to 5 ml with 0.9% NaCl and 1.5ml triplicates were placed in 20-ml glass scintillation vials and acidified with O.l-ml glacial acetic acid. The remaining 0.5 ml of mucosal homogenate was used for determination of pro-
UROLOGY
I
MAY 1987
I
VOLUME
AGENTS
TO THE RABBIT
ON 5. coli BLADDER
model
Male New Zealand white rabbits weighing 2 to 2.5 kg were sedated with an intramuscular injection (0.7 ml/Kg body weight) of a ketaminelzylazine mixture (29.2 mg/ml ketamine; 8.3 mg/ml zylazine). Surgical anesthesia was induced with 1 ml of 50 mg/ml pentobarbital given over the course of surgery. The rabbits were secured, and the urinary bladders were catheterized with a #8 catheter and the bladders were emptied. Prior to introduction of bacteria into the bladder, 10 ml of test solution was infused through the catheter with a lo-ml syringe. The control group received 10 ml of 0.9 % NaCl. During the one-minute exposure, the syringe plunger was gently pushed back and forth to increase the efficiency of extraction. The bladder was then flushed with three lo-ml aliquots of 0.9% NaCl. A total of 1.5 x lOa CFU 3H-labeled bacteria suspended in 1.5 ml of 0.9 % NaCl were introduced into the bladder and flushed in with 5 ml of 0.9 % NaCl. After a twenty-minute exposure to the labeled bacteria, the bladder was emptied and flushed with three lo-ml aliquots of 0.9% NaCl. The animal was then sacrificed with pentobarbital, the bladder was removed, and the mucosa was dissected free from the underlying muscle layer and assayed for 3H activity. Recording
OF VARIOUS
ADHERENCE
XXIX, NUMBER 5
1. Adherence assay peTformed as described in text. Bars represent mean f standard error of mean for N greater or equal to 6 animals. Data presented for 10 % (v/v) Triton X-l 00. Experiments using 1 mM Triton X-100 (0.06 % , molecular weight = 646.9, density = 1.0664 g/ml) resulted in similar increased adherence.
FIGURE
tein content. l4 Eighteen ml of scintillation fluid (Hydrofluor, National Diagnostics, Somerville, New Jersey) was added, and the vials were vortexed. 0. l-ml triplicates of the bacterial suspensions were also suspended in 20 ml of scintillation fluid. The radioactivity of the bacterial suspension (counts per minute) and the viable count (colony-forming units) were used to determine the CFU per CPM for each bacterial suspension. The radioactivity of the tissue samples were converted to the actual number of bacteria (CFU) attached to the mucosa by multiplication of the tissue CPM by the bacterial suspension CFU per CPM. This then was divided by the protein concentration of the mucosal digest to yield the number of colony-forming units of bacteria attached to the bladder mucosa per milligram of mucosal protein.
535
FIGURE 2. Representative photomicrographs of effect of various agents on periodic acid-Schiff staining of rabbit bladder. (A) Normal, control, untreated mucosa: distinct PAS-positive mucin layer seen at surface of mucosa: PAS staining at epithelial surface present, transitional epithelium. (B) 1 mM nitrofurantoin-treated indistinguishable from control. (C) 1 mM Briton X-100-treated mucosa: distinct absence of PAS-positive mutin layer. (0) 50% acetone-treated mucosa: similar absence of mucin layer (original magnification x 10).
Chemicals of USP or similar quality, stored according to the manufacturer’s specifications, were used for all tests. Means of assays performed in triplicate were counted as single datum points, and results are expressed as means f standard error of the mean for N greater or equal to 6 animals per experimental group. Statistical analysis was performed by analysis’of variance using the F distribution of Fisher with a post hoc Newman-Keuls multiple range test for paired comparisons. A probability value of less than 0.05 was required for statistical significance . Histochemistry
Full thickness (4-mm punch) bladder biopsy specimens were taken between the ureteral orifices from all animals from each experimental group. Specimens were fixed at room temperature in 10% buffered neutral formalin, sectioned, and stained with periodic acid-Schiff.
dimethyl sulfoxide (DMSO) did not increase E. coli adherence above the level obtained for mutin-intact controls. All other agents tested produced a statistically significant increase in bacterial adherence. Fifty per cent ethanol resulted in the largest increase followed by 0.4 N HCl, 100 % hexane, 50 % acetone, and 10 % Triton X100. The adherence increase produced by 50 % acetone was the most reproducible with a coefficient of variation of 0.39 (standard deviation divided by the mean). Representative PAS histologic sections are shown in Figure 2. Every agent which caused an increase in bacterial adherence (Triton X100, 50% acetone, hexane, 0.4 N HCl, and 50% ethanol) also removed the PAS-positive mucin layer. Neither 1 mM nitrofurantoin nor 50 % DMSO had any effect on the PAS-positive staining of bladder specimens of any experimental animals.
Results
Comment
Results are shown in Figure 1. Exposure of the bladder to 1.0 mM nitrofurantoin or 50%
The major impetus for this present investigation is the recent Gillespie et aL3 report which
536
UROLOGY
/ MAY1987
/ VOLUMEXXIX.NUMBER5
claims that nitrofurantoin acts as a surface active agent (surfactant) that destroys glycosaminoglycan on the surface of the bladder when used even for very short periods in the absence of infection. The only evidence presented for this concept is the observation that many patients who were diagnosed as having interstitial cystitis have been treated previously with this antibacterial. This is not unusual considering the fact that these patients have the symptoms of cystitis and therefore, have been treated with antibiotics empirically, based on the cystitis symptomatology. For some time nitrofurantoins have been known to induce interstitial pulmonary fibrosis, however, this is a rare occurrence with an estimated “worst case scenario” incidence of 0 .OOOQper cent. l5 True interstitial cystitis has never been reported, to our knowledge, as a side effect of nitrofurantoin therapy in any clinical scientific publication. The most important result of the present investigation is that exposure of the bladder to 1 .O mM nitrofurantoin for one minute does not remove the mucin layer nor increase bacterial adherence. l.O-mM of nitrofurantoin is the highest concentration possible for this agent in water due to its limited solubility. This is at least twice the urinary concentrations found in zero to twenty-four hours following a therapeutic dose of 100 mg qid.16 One must conclude from this result that nitrofurantoin does not remove or destroy the functional integrity of the bladder luminal surface mucin layer as has been suggested by other workers.3 While the time of exposure in this preliminary study is limited, the drug concentration in the bladder was over twice as high as obtained in clinical situations, and the sensitivity of our adherence assay would be expected to show any significant negative effect on the bladder surface. A similar exposure of the bladder mucosa to an equimolar concentration of the true surfactant Triton X-100 caused a greater than eightfold increase in bacterial adherence. Experiments are presently underway to determine the effect, if any, of more prolonged exposure. Fifty per cent dimethyl sulfoxide (DMSO) also was used in this investigation since it is used intravesically in the treatment of interstitial cystitis.17-2’J It is reassuring to know that this therapeutic agent also does not impair the functional antiadherence integrity of the bladder Other organic solvents luminal epithelium. (hexane, 50% acetone, and 50% ethanol) did
UROLOGY
/
MAY 1987
I
VOLUME XXIX,
NUMBER 5
increase bacterial adherence to the bladder. One could interpret this result as indicating that the antiadherence factor of the bladder luminal surface is not very soluble in DMSO, whereas it is readily soluble in hexane, 50% acetone, or 50 % ethanol. 3010 Courtyard Building, H.U.P. 3400 Spruce Street Philadelphia, Pennsylvania 19104 (DR. RUGGIERI) References 1. Class J: Interstitial cystitis profiled, Med Tribune, February 27, 1985, p 26. 2. Brody J: Obscure bladder ailment that trys physicians as well as its victims, New York Times, December 5, 1984, p C12. 3. Gillespie L, Said J, Cain W, and VanDerVeld R: Antibioticinduced interstitial cystitis: a model for cell membrane instability, J Urol 133: 177A (1985). 4. Mulholland SG: Lower urinary tract antibacterial defense mechanisms, Invest Urol 17: 93 (1978). 5. Parsons CL, Shrom SH, Hanno PM, and Mulholland SG: Bladder surface mucin: examination of possible mechanisms for its antibacterial effect, ibid 16: 196 (1978). 6. Shrom SH, Parsons CL, and Mulholland SG: Vesical defense: further evidence for a charge-related antiadherence mechanism, Surg Forum 29: 623 (1978). 7. Parsons CL, Greenspan C, and Mulholland SG: The primary antibacterial defense mechanism of the bladder, Invest Urol 13: 72 (1975). 8. Hanno PM, Fritz R, Wein AJ, and Mulholland SG: Heparin as antibacterial agent in the rabbit bladder, Urology 12: 411 (1978). 9. Hanno PM, et al: The protective effect of heparin in experimental bladder infection, J Surg Res 25: 324 (1978). 10. Hanno PM, Fritz RW, Mulholland SG, and Wein AJ: Heparin-examination of its antibacterial adsorption properties, Invest Urol 18: 273 (1981). 11. Ruggleri MR, Hanno PM, and Levin RM: The effects of heparin on the adherence of five species of urinary tract pathogens to urinary bladder mucosa, Urol Res 12: 199 (1984). 12. Hanno PM, Ruggieri MR, and Levin RM: Effects of several urinary tract pathogens: effects of heparin, Surg Forum 34: 698 (1983). 13. Ruggieri MR, Hanno PM, and Levin RM: Further characterization of bacterial adherence to urinary bladder mucosa: comparison with adherence to anion exchange resin, J Urol 134: 1019 (1985). 14. Lowry OH, Rosenbrough NJ, Farr AL, and Randall RJ: Protein measurement using the Folin phenol reagent, J Biol Chem 193: 265 (1951). 15. D’Arcy PF: Drug interactions and reactions update: nitrofurantoin, Drug Intel1 Clin Pharm 19: 540 (1985). 16. Lippman RW, Wrobel CJ, Ress R, and Hoyt R: A theory concerning recurrence of urinary infection: prolonged administration of nitrofurantoin for prevention, J Ural 89: 77 (1958). 17. Fowler JE: Prospective study of intravesical dimethylsulfoxide in treatment of suspected early interstitial cystitis, Urology 18: 21 (1981). 18. Engberg AEA, Frodin L, and Jonsson G: The use of dimethyl sulfoxide (DMSO) in the treatment of interstitial cystitis, Stand J Urol Nephrol 12: 129 (1978). 19. Shirlev SW. Stewart BH. and Mirelman S: Dimethvl sulfoxide in the’treatment of inflammatory genitourinary disorders, Urology 11: 215 (1978). 20. Stewart BH, and Shirley SW: Further experience with intravesical dimethyl sulfoxide in the treatment of interstitial cystitis, J Urol 116: 36 (1976).
537
NOT SURFACE ACTIVE AGENT
IN RABBIT URINARY BLADDER* MICHAEL PHILIP ROBERT
R. RUGGIERI,
PH.D.
M. HANNO, M.D. M. LEVIN,
PH.D.
From the Division of Urology, University of Pennsylvania School of Medicine, and Veterans Administration Medical Center, Philadelphia, Pennsylvania
ABSTRACT-It has been recently suggested that nitrofurantoin may induce symptoms of interstitial cystitis by acting as a surface active agent that destroys glycosaminoglycan (GAG) on the bladder surface. Evidence accumulated over the past decade has demonstrated that the bladder surface GAG prevents bacterial adherence. In this experiment, exposure of the bladder lumen to nitrofurantoin at more than twice the therapeutic concentration did not destroy the bladder GAG layer (as evidenced by periodic acid-Schiff histochemistry) nor increase bacterial adherence as did a true surface active agent (Triton X-100). Acid treatment as well as all tested organic solvents except 50 % dimethyl sulfoxide (DMSO) also removed the bladder GAG layer and increased bacterial adherence. These results indicate that neither nitrofurantoin nor 50 % DMSO has adverse effects on the bladder surface and thus is unlikely to initiate the interstitial cystitis symptom complex by means of surfactant activity.
There have been several reports in the recent literature, particularly in the lay news media, suggesting that antibacterial therapy may sometimes induce interstitial cystitis in certain patients. 1,2 It has been suggested that one antibacterial agent in particular, nitrofurantoin, acts as a surface active agent (surfactant) destroying the glycosaminoglycan layer lining the bladder luminal sm-face.3 Experimental work in our laboratory and others over the past several years has demonstrated that the mucin layer lining the bladder luminal epithelium prevents bacterial adherence. Removing this mucin layer with an acid rinse leads to increased bacterial adherencea4m7 Exposing this mucin-deficient bladder to either exogenous glycosaminoglycans-12 or to a solution of blad*Supported in part by grants from Veterans Administration, NIH Grant RO-I-AM 6508-01, and the McCabe Fund.
534
der mucosal extract from a different species13 restores bacterial adherence to the low levels of the mucin-intact state. We investigated the effect of nitrofurantoin at more than double the therapeutic concentration on the periodic acid-Schiff (PAS) staining and functional antiadherence integrity of the bladder luminal surface. In addition, a true surfactant (Triton X-100) and organic solvents were also tested to determine if they could remove the mucin layer as evidenced by PAS histochemistry and increased bacterial adherence. Material and Methods Preparation of bacteria Lyophylized bacterial neotype Escherichia coli 11775 (purchased from the American Type Culture Collection, Bethesda, Maryland) were rehydrated in sterile 0.9 % NaCl and serially
UROLOGY
i
MAY 1987
/
VOLUME XXIX, NUMBER 5
EFFECT
passed repeatedly in static brain-heart infusion broth (BHI; Difco Laboratories, Detroit, Michigan) at 37°C. To label the organisms with 3H, a 0.4 % inoculum (v/v) was added to 4 ml of fresh BHI containing 5 PCi 3H-Adenine/ml (New England Nuclear, Boston, Massachusetts) and incubated statically at 37°C for eighteen to twenty-four hours. The bacteria were sedimented at 3,000 x g for twenty minutes and resuspended in their original volume of 0.9 % NaCl. Colony-forming units (CFU) were determined by serial dilution as previously described.11J3 Bacterial suspensions were prepared for a given experiment with an optical density adjusted to 0.2 U to yield a constant lOa CFUlml suspension, Mu&a-deficient
rabbit
bladder
of radioactivity
Bladder mucosae were digested overnight in 1 ml of 1 .O N NaOH at 37°C. The volume was then brought to 5 ml with 0.9% NaCl and 1.5ml triplicates were placed in 20-ml glass scintillation vials and acidified with O.l-ml glacial acetic acid. The remaining 0.5 ml of mucosal homogenate was used for determination of pro-
UROLOGY
I
MAY 1987
I
VOLUME
AGENTS
TO THE RABBIT
ON 5. coli BLADDER
model
Male New Zealand white rabbits weighing 2 to 2.5 kg were sedated with an intramuscular injection (0.7 ml/Kg body weight) of a ketaminelzylazine mixture (29.2 mg/ml ketamine; 8.3 mg/ml zylazine). Surgical anesthesia was induced with 1 ml of 50 mg/ml pentobarbital given over the course of surgery. The rabbits were secured, and the urinary bladders were catheterized with a #8 catheter and the bladders were emptied. Prior to introduction of bacteria into the bladder, 10 ml of test solution was infused through the catheter with a lo-ml syringe. The control group received 10 ml of 0.9 % NaCl. During the one-minute exposure, the syringe plunger was gently pushed back and forth to increase the efficiency of extraction. The bladder was then flushed with three lo-ml aliquots of 0.9% NaCl. A total of 1.5 x lOa CFU 3H-labeled bacteria suspended in 1.5 ml of 0.9 % NaCl were introduced into the bladder and flushed in with 5 ml of 0.9 % NaCl. After a twenty-minute exposure to the labeled bacteria, the bladder was emptied and flushed with three lo-ml aliquots of 0.9% NaCl. The animal was then sacrificed with pentobarbital, the bladder was removed, and the mucosa was dissected free from the underlying muscle layer and assayed for 3H activity. Recording
OF VARIOUS
ADHERENCE
XXIX, NUMBER 5
1. Adherence assay peTformed as described in text. Bars represent mean f standard error of mean for N greater or equal to 6 animals. Data presented for 10 % (v/v) Triton X-l 00. Experiments using 1 mM Triton X-100 (0.06 % , molecular weight = 646.9, density = 1.0664 g/ml) resulted in similar increased adherence.
FIGURE
tein content. l4 Eighteen ml of scintillation fluid (Hydrofluor, National Diagnostics, Somerville, New Jersey) was added, and the vials were vortexed. 0. l-ml triplicates of the bacterial suspensions were also suspended in 20 ml of scintillation fluid. The radioactivity of the bacterial suspension (counts per minute) and the viable count (colony-forming units) were used to determine the CFU per CPM for each bacterial suspension. The radioactivity of the tissue samples were converted to the actual number of bacteria (CFU) attached to the mucosa by multiplication of the tissue CPM by the bacterial suspension CFU per CPM. This then was divided by the protein concentration of the mucosal digest to yield the number of colony-forming units of bacteria attached to the bladder mucosa per milligram of mucosal protein.
535
FIGURE 2. Representative photomicrographs of effect of various agents on periodic acid-Schiff staining of rabbit bladder. (A) Normal, control, untreated mucosa: distinct PAS-positive mucin layer seen at surface of mucosa: PAS staining at epithelial surface present, transitional epithelium. (B) 1 mM nitrofurantoin-treated indistinguishable from control. (C) 1 mM Briton X-100-treated mucosa: distinct absence of PAS-positive mutin layer. (0) 50% acetone-treated mucosa: similar absence of mucin layer (original magnification x 10).
Chemicals of USP or similar quality, stored according to the manufacturer’s specifications, were used for all tests. Means of assays performed in triplicate were counted as single datum points, and results are expressed as means f standard error of the mean for N greater or equal to 6 animals per experimental group. Statistical analysis was performed by analysis’of variance using the F distribution of Fisher with a post hoc Newman-Keuls multiple range test for paired comparisons. A probability value of less than 0.05 was required for statistical significance . Histochemistry
Full thickness (4-mm punch) bladder biopsy specimens were taken between the ureteral orifices from all animals from each experimental group. Specimens were fixed at room temperature in 10% buffered neutral formalin, sectioned, and stained with periodic acid-Schiff.
dimethyl sulfoxide (DMSO) did not increase E. coli adherence above the level obtained for mutin-intact controls. All other agents tested produced a statistically significant increase in bacterial adherence. Fifty per cent ethanol resulted in the largest increase followed by 0.4 N HCl, 100 % hexane, 50 % acetone, and 10 % Triton X100. The adherence increase produced by 50 % acetone was the most reproducible with a coefficient of variation of 0.39 (standard deviation divided by the mean). Representative PAS histologic sections are shown in Figure 2. Every agent which caused an increase in bacterial adherence (Triton X100, 50% acetone, hexane, 0.4 N HCl, and 50% ethanol) also removed the PAS-positive mucin layer. Neither 1 mM nitrofurantoin nor 50 % DMSO had any effect on the PAS-positive staining of bladder specimens of any experimental animals.
Results
Comment
Results are shown in Figure 1. Exposure of the bladder to 1.0 mM nitrofurantoin or 50%
The major impetus for this present investigation is the recent Gillespie et aL3 report which
536
UROLOGY
/ MAY1987
/ VOLUMEXXIX.NUMBER5
claims that nitrofurantoin acts as a surface active agent (surfactant) that destroys glycosaminoglycan on the surface of the bladder when used even for very short periods in the absence of infection. The only evidence presented for this concept is the observation that many patients who were diagnosed as having interstitial cystitis have been treated previously with this antibacterial. This is not unusual considering the fact that these patients have the symptoms of cystitis and therefore, have been treated with antibiotics empirically, based on the cystitis symptomatology. For some time nitrofurantoins have been known to induce interstitial pulmonary fibrosis, however, this is a rare occurrence with an estimated “worst case scenario” incidence of 0 .OOOQper cent. l5 True interstitial cystitis has never been reported, to our knowledge, as a side effect of nitrofurantoin therapy in any clinical scientific publication. The most important result of the present investigation is that exposure of the bladder to 1 .O mM nitrofurantoin for one minute does not remove the mucin layer nor increase bacterial adherence. l.O-mM of nitrofurantoin is the highest concentration possible for this agent in water due to its limited solubility. This is at least twice the urinary concentrations found in zero to twenty-four hours following a therapeutic dose of 100 mg qid.16 One must conclude from this result that nitrofurantoin does not remove or destroy the functional integrity of the bladder luminal surface mucin layer as has been suggested by other workers.3 While the time of exposure in this preliminary study is limited, the drug concentration in the bladder was over twice as high as obtained in clinical situations, and the sensitivity of our adherence assay would be expected to show any significant negative effect on the bladder surface. A similar exposure of the bladder mucosa to an equimolar concentration of the true surfactant Triton X-100 caused a greater than eightfold increase in bacterial adherence. Experiments are presently underway to determine the effect, if any, of more prolonged exposure. Fifty per cent dimethyl sulfoxide (DMSO) also was used in this investigation since it is used intravesically in the treatment of interstitial cystitis.17-2’J It is reassuring to know that this therapeutic agent also does not impair the functional antiadherence integrity of the bladder Other organic solvents luminal epithelium. (hexane, 50% acetone, and 50% ethanol) did
UROLOGY
/
MAY 1987
I
VOLUME XXIX,
NUMBER 5
increase bacterial adherence to the bladder. One could interpret this result as indicating that the antiadherence factor of the bladder luminal surface is not very soluble in DMSO, whereas it is readily soluble in hexane, 50% acetone, or 50 % ethanol. 3010 Courtyard Building, H.U.P. 3400 Spruce Street Philadelphia, Pennsylvania 19104 (DR. RUGGIERI) References 1. Class J: Interstitial cystitis profiled, Med Tribune, February 27, 1985, p 26. 2. Brody J: Obscure bladder ailment that trys physicians as well as its victims, New York Times, December 5, 1984, p C12. 3. Gillespie L, Said J, Cain W, and VanDerVeld R: Antibioticinduced interstitial cystitis: a model for cell membrane instability, J Urol 133: 177A (1985). 4. Mulholland SG: Lower urinary tract antibacterial defense mechanisms, Invest Urol 17: 93 (1978). 5. Parsons CL, Shrom SH, Hanno PM, and Mulholland SG: Bladder surface mucin: examination of possible mechanisms for its antibacterial effect, ibid 16: 196 (1978). 6. Shrom SH, Parsons CL, and Mulholland SG: Vesical defense: further evidence for a charge-related antiadherence mechanism, Surg Forum 29: 623 (1978). 7. Parsons CL, Greenspan C, and Mulholland SG: The primary antibacterial defense mechanism of the bladder, Invest Urol 13: 72 (1975). 8. Hanno PM, Fritz R, Wein AJ, and Mulholland SG: Heparin as antibacterial agent in the rabbit bladder, Urology 12: 411 (1978). 9. Hanno PM, et al: The protective effect of heparin in experimental bladder infection, J Surg Res 25: 324 (1978). 10. Hanno PM, Fritz RW, Mulholland SG, and Wein AJ: Heparin-examination of its antibacterial adsorption properties, Invest Urol 18: 273 (1981). 11. Ruggleri MR, Hanno PM, and Levin RM: The effects of heparin on the adherence of five species of urinary tract pathogens to urinary bladder mucosa, Urol Res 12: 199 (1984). 12. Hanno PM, Ruggieri MR, and Levin RM: Effects of several urinary tract pathogens: effects of heparin, Surg Forum 34: 698 (1983). 13. Ruggieri MR, Hanno PM, and Levin RM: Further characterization of bacterial adherence to urinary bladder mucosa: comparison with adherence to anion exchange resin, J Urol 134: 1019 (1985). 14. Lowry OH, Rosenbrough NJ, Farr AL, and Randall RJ: Protein measurement using the Folin phenol reagent, J Biol Chem 193: 265 (1951). 15. D’Arcy PF: Drug interactions and reactions update: nitrofurantoin, Drug Intel1 Clin Pharm 19: 540 (1985). 16. Lippman RW, Wrobel CJ, Ress R, and Hoyt R: A theory concerning recurrence of urinary infection: prolonged administration of nitrofurantoin for prevention, J Ural 89: 77 (1958). 17. Fowler JE: Prospective study of intravesical dimethylsulfoxide in treatment of suspected early interstitial cystitis, Urology 18: 21 (1981). 18. Engberg AEA, Frodin L, and Jonsson G: The use of dimethyl sulfoxide (DMSO) in the treatment of interstitial cystitis, Stand J Urol Nephrol 12: 129 (1978). 19. Shirlev SW. Stewart BH. and Mirelman S: Dimethvl sulfoxide in the’treatment of inflammatory genitourinary disorders, Urology 11: 215 (1978). 20. Stewart BH, and Shirley SW: Further experience with intravesical dimethyl sulfoxide in the treatment of interstitial cystitis, J Urol 116: 36 (1976).
537