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Biomedical subjects

M R Ruggieri

Publications and source records attributed to M R Ruggieri.

At least 37 records · Page 2Linked to original sources
PubMed1993

Effect of repeated instillation of interstitial cystitis urine on the rabbit urinary bladder.

One theory for the etiology of interstitial cystitis (IC) proposes toxic substances in the urine. This hypothesis was tested in our laboratory by infusing urine into the bladders of rabbits twice weekly for six weeks. For the first study rabbits were treated by one-hour biweekly intravesical exposure to urine from a symptomatic interstitial cystitis patient, a normal volunteer, or physiologic saline. For the second study, animals were exposed to both a high and a low molecular weight fraction of urine pooled from 7 interstitial cystitis patients, 7 normal female volunteers, and physiologic saline. At the end of six weeks the animals were cystoscoped and the bladder was removed the following day for histologic and contractile studies. Post-distention glomerulations were observed in 3 of the 4 whole IC urine-treated animals and an ulcer identical to the classic "Hunner's ulcer" was seen in one of these animals. Post-distention petechial hemorrhages were also noted in all 5 of the high molecular weight IC urine-treated animals but in none of the others, suggesting a difference between IC and normal urine. These IC urine-treated groups also showed the greatest degree of histologic changes including edema and plasma cell infiltrates in the lamina propria, submucosa and perivascular tissue. However, there was no statistically significant difference in bladder capacity, micturition patterns, or contractile response of bladder strips. These results indicate that there are substances with nominal molecular weight greater than 10 kD in interstitial cystitis urine that induce changes in the rabbit bladder that resemble bladders of interstitial cystitis patients.

Administration, Intravesical↗
PubMed1993

Effect of chronic neuroleptic treatment on central and peripheral muscarinic receptors.

The regulation of muscarinic acetylcholine receptor (MAChR) subtypes in rat striatum, bladder and heart was examined following a 14-day administration of neuroleptics (clozapine or fluphenazine), anticholinergics (atropine) or a combination of anticholinergics and neuroleptics. Levels of MAChRs were ascertained by the use of immunoprecipitation and radioligand binding. The combined treatment of fluphenazine and atropine produced an increase in all MAChR subtype levels in striatum with m1 receptor levels having the largest increase (270%) from control. A significant increase (105%) was also seen striatal in m2 receptor levels. Residual muscarinic receptor levels, representing the m3 and m4 subtypes, were increased (72%) to a lesser degree above control. Fluphenazine treatment alone increased levels of the m2 MAChR, whereas clozapine administration had no significant effect on levels of any MAChR subtype in this tissue. Administration of the cholinergic antagonist, atropine, showed a significant increase (89%) in the striatal m1 MAChR subtype. Of the MAChRs found in rat bladder and rat heart, the m2 subtype has been shown to be the most abundant. Results from the rat bladders indicated a reduction (50%) in muscarinic antagonist binding that was limited to the fluphenazine treatment group. In heart, atropine treatment alone produce a slight increase (ca. 10%) in receptor binding. No significant effect on muscarinic receptor levels was seen with the other treatment groups. These data demonstrate that there are differences in muscarinic receptor level modulation between central and peripheral tissues.

Animals↗
PubMed1992

Decreased levels of muscarinic receptors in bladders from the alcohol preferring rat line.

The Bmax for [3H]QNB binding in the bladders of alcohol preferring (AA) rats was only approximately 60% of that in the alcohol non-preferring (ANA) rats. No significant change in Bmax for [3H]QNB binding in bladder was observed between alcohol insensitive (AT) and alcohol sensitive (ANT) rats. No significant change in Kd for [3H]QNB binding in bladder was observed between the four different rat lines studied. Therefore, alcohol preference but not sensitivity is associated with a decrease in muscarinic receptor density in the rat bladder. Because all of the rats used in this study were ethanol-naive, the decrease in muscarinic receptor density in the bladders of alcohol preferring rats is associated with genetic factors inherent to this rat line. Further studies are needed to determine if these observations are tissue specific or specific to the m2 subtype, which predominates in the rat bladder.

Alcohol Drinking↗
PubMed1992

Characterization of bovine bladder mucin fractions that inhibit Escherichia coli adherence to the mucin deficient rabbit bladder.

We have previously shown that a dialyzed, lyophilized saline extract from bovine urothelium can restore the antiadherence activity of the rabbit bladder following mucin removal with 50% acetone. This report describes results of initial purification of antiadherence factor(s) from bovine bladder mucin and describes results of biochemical analysis in an attempt to elucidate possible mechanism of this antiadherence activity. Separation performed by gel filtration (Spectra gel AcA 34, 20-350 KD range) results in three fractions. Only the low molecular weight fraction had a statistically significant inhibitory effect on bacterial adherence to the mucin deficient rabbit bladder. After overnight dialysis against running deionized water and lyophilization, the crude extract contained 60% protein while gel filtration fractions 1-3 contained 35%, 90% and 15% by weight respectively. The first fraction (apparent high molecular weight, greater than 350 kD) did not appear to enter SDS polyacrylamide electrophoresis gels (SDS-PAGE, 3-12%) or agarose gels (0.5%) to any significant extent. In the fractions that displayed antiadherence activity (the crude extract, fractions 2 and 3) SDS-PAGE bands were seen corresponding to an apparent molecular weight of 78 kD in addition to bands co-migrating with bovine serum albumin (BSA). BSA itself slightly increases bacterial adherence in this model. Most of the albumin of the crude extract was found in the second fraction (60%). On the other hand most of the sulfate and sugar of the crude extract was found in the third, low molecular weight fraction. Since sulfated polysaccharides such as heparin and dextran sulfate are very effective antiadherence agents in this rabbit bladder model, it is conceivable that the sulfated sugar content of the third fraction is responsible for its antiadherence effect on the mucin deficient rabbit bladder.

Albumins↗
PubMed1992

Detubularization-induced contractile response change of the ileum following ileocystoplasty.

We reported previously that following ileocystoplasty the structure and pharmacologic response of the implanted ileum changes towards that of the bladder. Specifically, the relaxation response to alpha adrenergic (methoxamine) and purinergic (ATP) stimulation reverses to a contractile response one month after the ileal segment is surgically made part of the urinary bladder. The present study was designed to investigate possible signals for this change and also to determine whether bladder responses would mimic the ileum if surgically interposed into the ileal stream. Rabbits in group 1 underwent bladder interposition into the functioning terminal ileum, rabbits in group 2 underwent tubularized ileocystoplasty and rabbits in group 3 underwent detubularized ileocystoplasty with urinary diversion. Twelve rabbits survived and were available for evaluation; five in group 1, three in group 2 and four in group 3. Analysis was done six weeks after surgery. In group 1 animals, the interposed bladder showed epithelial changes towards ileum and also a change in its in-vitro contractile responses towards that of ileum. In group 2 animals the tubular cystoplastic ileum showed minimal functional and morphologic changes. In group 3 animals, the defunctionalized, detubular cystoplastic ileum showed alpha adrenergic and purinergic response changes towards bladder. These results indicate that detubularization with interruption in the arrangement of smooth muscle fibers as well as the breach in the integrity of neuronal connections is likely to be the primary signal for the change in the ileum towards bladder induced by cystoplasty. The results can not rule out reinnervation of the intestinal segment by bladder nerves. In addition these data demonstrate that the pharmacologic response of the bladder changes towards the ileum within six weeks after the bladder is surgically made part of the ileum.

Adenosine Triphosphate↗
PubMed1990

Bladder purinergic receptors.

In rabbits the contractile response of the urinary bladder is only partially due to cholinergic innervation since atropine does not completely block neuronally mediated contractions. In the human bladder this atropine resistance is controversial with some reporting atropine resistance in vitro while others have stated that the atropine resistance is also tetrodotoxin resistant. Results of the present investigation demonstrate that an atropine resistant, tetrodotoxin sensitive contraction can be evoked in some, but not all human bladder strips. Evidence accumulated over the past few decades indicates that this atropine resistant contraction may be mediated by ATP or a related purine compound. Studies presented herein are designed to develop a radioligand assay for this purinergic receptor. Initial studies indicated that the hydrolysis resistant ATP analog beta, gamma methylene ATP offers several advantages over ATP as a potential radioligand. It is only slowly hydrolyzed by endogenous ATPase and does not inhibit the hydrolysis of ATP indicating that it probably does not bind to the active sites of endogenous ATP hydrolyzing enzymes. In addition beta, gamma methylene ATP is 10-100 fold more potent than ATP itself in stimulating contractions of the urinary bladder in-vitro. The radioligand binding assay herein described can be used to quantitate the density of purinergic receptors, an essential step for determining the role of this system in urinary bladder function and dysfunction. Application of this assay could form the foundation for development of a new class of therapeutic agents for the treatment of urinary bladder dysfunction based on modulation of the purinergic nervous system.

Adenine Nucleotides↗
PubMed1989

Functional and biochemical alterations in the rabbit urinary bladder following ileocystoplasty.

Although the use of ileocystoplasty has increased significantly in recent years, very little is known concerning the smooth muscle properties of the implanted bowel segment. In a previous study, preliminary evidence was presented which indicated that the pharmacological response of the cytoplastic ileal segment to autonomic agonists changed toward that of the bladder. The present study extends and expands these preliminary observations on the physiology and pharmacology of augmentation cystoplasty. Augmentation cystoplasty with detubularized ileum was carried out in 16 rabbits. In vivo and in vitro physiological and pharmacological studies were carried out one and three months after surgery. The results can be summarized as follows: 1) in-vivo CMG at one month was similar to that of the preoperative bladder, but at three months there was a 24% increase in capacity, with the presence of multiple phasic contractions beginning at a volume of approximately 65% of capacity. 2) The frequency and magnitude of spontaneous activity in the cystoplastic ileum did not significantly alter from that of the normal ileum. 3) Cystoplastic ileum responded to muscarinic stimulation differently from the normal ileum. The bladder responded with an increase in the tension whereas the ileum responded with an increase in the frequency and amplitude of phasic contractions. The cystoplastic ileum responded with a pronounced sustained contraction with phasic contractions superimposed. The tonic contraction at three months was of a significantly greater magnitude than that at one month. 4) The qualitative and quantitative response to field stimulation of the cystoplastic ileum was altered from that of the ileum towards that of the bladder. 5) The normal bladder contains greater amount of creatine phosphate and lesser amounts of creatine than the normal ileum. Cystoplasty, after three months induced a change in the ileal segment towards the bladder (increased creatine phosphate and decreased creatine). 6) The normal ileum was found to have greater number of muscarinic receptors than the normal bladder whereas the cystoplastic ileum at three months was intermediate.

Animals↗
PubMed1989

Effects of muscarinic stimulation on intracellular calcium in the rabbit bladder: comparison with metabolic response.

Urinary bladder emptying is mediated primarily by a co-ordinated contraction of the bladder body in response to parasympathetic stimulation and muscarinic receptor activation. In a previous study using surface spectrophotometry to monitor the nicotinamide adenine dinucleotide (oxidized form)/nicotinamide adenine dinucleotide (reduced form) (NADH/NAD) ratio, we demonstrated that muscarinic stimulation results in a rapid decrease in this ratio which precedes the contractile response, and that the ED50 for the NADH response is significantly lower than the ED50 for contraction. The current study was designed to correlate changes in intracellular free calcium using FURA-2 fluorescence with both the contractile and metabolic response to muscarinic stimulation. Isolated strips of urinary bladder body were monitored in vitro for changes in intracellular free calcium, NADH/NAD ratio, and contraction. Intracellular free calcium was monitored by preincubation with FURA-2 AM and continuously measuring the fluorescence with an MB2 surface spectrofluorometer using excitation wavelengths of 340 and 380 nm, and an emission wavelength of 510 nm. The NADH/NAD ratio was monitored with the MB2 surface spectrophotometer using an excitation wavelength of 366 nm and an emission wavelength of 450 nm. Contraction was monitored using an isometric force transducer connected to a Grass model D polygraph. The results can be summarized as follows: (1) Bethanechol stimulates a sharp decrease in the NADH/NAD ratio, a rapid increase in intracellular free calcium, and a slower increase in contractile force. (2) The ED50 for NADH fluorescence was significantly less than the ED50 for either contraction or calcium fluorescence which were equal to each other.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Dissociation of the metabolic from the contractile response to muscarinic stimulation in the rabbit urinary bladder.

The calcium dependence of contraction and NADH fluorescence was investigated in rabbit bladder stimulated with bethanechol or KCl. The absence of calcium in the bathing solution induced a rightward shift in the dose response to bethanechol for both contraction and NADH fluorescence. The contractile response was shifted to a greater degree than the fluorescence response and the maximal response to bethanechol was reduced by 80% for contraction but only 20% for NADH fluorescence. This rightward shift was also induced by the benzothiazepine calcium antagonist diltiazem (200 microM) and again the contractile response was shifted significantly more than the fluorescence response. The combination of zero calcium and 200 microM diltiazem virtually abolished contractions but only inhibited the NADH fluorescence by 65% at maximally effective bethanechol concentrations. Unlike the effect of diltiazem on the response to bethanechol, diltiazem (200 microM) shifted both the contraction and fluorescence curves to the right equally in response to KCl stimulation. These results indicate that a metabolic response to muscarinic stimulation (decreased NADH) can occur in the absence of any observable contractile response. This metabolic response may be due to post receptor signal processing events. For KCl stimulation, the NADH response is probably secondary to and a result of the contractile response.

Animals↗
PubMed1988

Defective antiadherence activity of bladder extracts from patients with recurrent urinary tract infection.

A substantial body of animal work indicates that the initial first line defense against invading microorganisms in the urinary tract is the antiadherence activity of the surface mucin layer. Previous work has demonstrated that bacterial adherence to anion exchange resin can be used as a model for adherence to the mucin deficient rabbit bladder. This anion exchange resin adherence model can also be used as a rapid screen for potential antiadherence agents. In vitro saline extracts of bladder mucosa from various mammalian species including man have been shown to inhibit bacterial adherence to both anion exchange resin and the mucin deficient rabbit bladder. The present report investigates the ability of in vivo saline bladder washes from several groups of patients to inhibit bacterial adherence to anion exchange resin. This has an advantage over other methods of quantitation or visualization of mucin since it is the ability of the bladder extract to prevent bacterial adherence, and not merely the quantity of mucin, that determines the effectiveness of the mucin lining in preventing bacterial attachment. Bladder washes from patients with recurrent urinary tract infection were significantly less potent at inhibiting bacterial adherence than extracts from other groups of patients. This decreased functional antiadherence activity of bladder extracts may help explain the frequency of urinary tract infection in this group of patients.

Adult↗
PubMed1988

Effect of chronic nitrofurantoin on the rabbit urinary bladder.

Interstitial cystitis is a pathological condition whose symptoms mimic urinary tract infection and include urgency, frequency, and moderate to severe pain. Many more women than men are affected, with antibiotic therapy being the usual first treatment approach based on symptomology. Some clinicians believe that chronic antibiotic therapy may play an etiological role in interstitial cystitis; however neither clinical nor experimental data support their opinion. The implied pathogenesis of antibiotic injury is an alteration of the bladder mucosa and its protective mucin coating to allow urine-mediated damage to the bladder wall. The purpose of this study is to evaluate rabbit urinary bladder function and morphology during chronic nitrofurantoin administration. The results demonstrate that up to twelve months of chronic nitrofurantoin administration produce no changes in 1) bacterial adherence to the rabbit bladder mucosa, 2) specific antibacterial adherence activity of the bladder mucin, and 3) ultrastructure of the mucosa, submucosa, and muscularis.

Animals↗
PubMed1988

Effect of bethanechol on glycolysis and high energy phosphate metabolism of the rabbit urinary bladder.

The urinary bladder, similar to other smooth muscles, utilizes glucose as one of its primary sources of metabolic energy. We have studied the effect of bethanechol on both glycolysis and high energy phosphate metabolism. The results can be summarized as follows: bethanechol administration in vitro stimulates a 30% decrease in intracellular glycogen, a 100% increase in lactic acid production, and an 80% increase in CO2 generation. Although there was a rapid and sustained decrease in the intracellular concentration of creatine phosphate, there was only a minor decrease in the intracellular concentration of ATP. There were no changes in adenine uptake or de novo ATP synthesis.

Adenine↗
PubMed1988

Identification of receptor subtypes in the rabbit and human urinary bladder by selective radio-ligand binding.

Recent advances in receptor technology have demonstrated that subtypes of each autonomic receptor exist. Using both direct radio-ligand studies and the inhibition of receptor binding by subtype-selective pharmacological antagonists, we have studied the distribution of subtypes of alpha and beta adrenergic receptors and muscarinic cholinergic receptors in the urinary bladder of the rabbit and man. Alpha adrenergic receptors were quantified by direct binding of tritiated prazosin (alpha-1), yohimbine (alpha-2), and the non-selective alpha adrenergic ligand dihydroergocriptine (DHE). These studies demonstrated that the distribution of alpha receptor subtypes in the bladder base (for both rabbit and human) is approximately 80% alpha-1 and 20% alpha-2. Beta receptor subtypes were identified by the inhibition of the non-selective ligand 3H-dihydroalprenalol (DHA) by the beta-1 selective inhibitor ICI-89 and the beta-2 selective inhibitor ICI-118. Initial studies demonstrated that the beta adrenergic density of the bladder body was 92 fmol per mg. protein for the rabbit and 32 fmol per mg. protein for human bladder body. Inhibition of DHA binding by ICI-118 demonstrated a single class of receptor with an IC50 of approximately 0.013 microM for both rabbit and human. Inhibition of DHA binding by ICI-89 also demonstrated one class of receptors with an IC50 of approximately 9.0 microM for both species. These results indicate that there are primarily beta-2 receptors in the rabbit and human bladder body. Although the number of muscarinic subtypes in existence is currently being re-evaluated, there are at least two which can be identified by the selective muscarinic agent pirenzepine (PZP). The brain has been shown to contain both high and low affinity PZP sites. Using both direct PZP binding to the bladder body, and the inhibition by PZP of the non-selective radio-ligand quinuclidinyl benzylate (QNB), we have demonstrated that both the rabbit and human bladder body have no observable high affinity PZP-selective binding and the inhibition of 3H-QNB by PZP demonstrated that there was only the low-affinity PZP binding site. Although receptor subtypes in the bladder have been the subject of numerous investigations, this is the first study describing the distribution of both adrenergic and cholinergic receptor subtypes in both the rabbit and human.

Animals↗
PubMed1988

Effect of chronic atropine administration on the rat urinary bladder.

Micturition is accomplished via a coordinated contraction of the urinary bladder body mediated primarily by muscarinic receptor stimulation. Theoretically, bladder function may be modified by pharmacologically altering either the muscarinic receptor density and/or the magnitude of the response to receptor activation. In the central nervous system, autonomic receptor density can be modified by chronic administration of specific receptor agonists and antagonists. The chronic administration of receptor agonists induces a decrease in the specific receptor density whereas the chronic administration of antagonists induces an increase in the specific receptor density. Although these induced alterations in receptor density occur in the CNS, there have been few studies on peripheral tissue. For the current study, we have administered L-atropine chronically to rats (five mg./kg./day) using implanted osmotic pumps. Using direct radioligand binding techniques, the muscarinic receptor density of the rat brain (cortex) and urinary bladder were determined following six hours, 12 hours, one, two, four, seven, 11 and 14 days of atropine administration. In addition, we have also determined the effect of atropine administration on bladder weight and the response of isolated strips of the bladder to bethanechol, a specific muscarinic agonist. For both the brain and the bladder, the receptor density increased progressively and reached a maximum by seven days. At 14 days of atropine administration, the density of muscarinic receptors in rat brain increased significantly (p less than .05) from 2956 +/-74 fmoles/mg. protein to 3800 +/-170 fmoles/mg. protein. The muscarinic receptor density of the rat urinary bladder increased significantly from 115 +/-10 fmole/mg. protein to 165 +/-14 fmole/mg. protein. Although there was a 42% increase in bladder mass, the contractile response of isolated strips to bethanechol did not change significantly. This study demonstrates that the urinary bladder can respond to the chronic administration of atropine with a significant increase in the density of muscarinic receptors. The magnitude of the increase observed was slightly greater than the magnitude observed for muscarinic receptors isolated from the brain cortex.

Animals↗
PubMed1988

The effects of short-term in-vivo ischemia on the contractile function of the rabbit urinary bladder.

The proper functioning of any smooth muscle requires adequate perfusion with oxygen and nutrients. Ischemia compromises both these factors and results in dysfunction, the extent depending on the degree and duration of ischemia. This study determined the effects of one, two and four weeks in vivo ischemia on the capacity, compliance and contractile function of the rabbit urinary bladder. Morphological changes were also studied with light microscopy. Different degrees of ischemia were achieved as follows. In the unilateral group the vesical artery was tied on one side and the animals were sacrificed at one week or two weeks. In the bilateral group the vesical arteries on both sides were tied and the animals were sacrificed one week later. In the bilateral staged group the vesical artery was tied on one side and after one week the contralateral artery was ligated, and the animals sacrificed one week after the second procedure. Muscle strips were studied for contractile response, with a distinction being made between the ipsilateral and contralateral side of vessel ligation in the unilateral group. The results were as follows. 1) In the unilateral group there was a 72% reduction in the contractile response of the dome of the bladder to bethanecol on the side of vessel ligation and a 32% reduction on the contralateral side. The response to methoxamine on the base was reduced by 44%, with no difference between the ipsilateral and contralateral side. 2) Bilateral vessel ligation resulted in a 97% reduction in contractile response to bethanechol on the dome and a 75% in the response of the base to methoxamine. 3) Staged bilateral ligation resulted in a 69% reduction in the contractile response of the dome to bethanechol and a 18% reduction in the response of the base to methoxamine. Ischemia caused a marked reduction in the compliance and capacity of the bladder in all the three groups, with the most marked changes in the bilateral group. Multiple spontaneous contractions were noted in the three groups during the filling phase of the cystometrograms. Histological features correlated well with the functional changes in the different groups.

Animals↗
PubMed1988

Functional effects of imipramine on the rabbit urinary bladder: an in-vitro study.

Imipramine is a tricyclic antidepressant that has been demonstrated to be useful in the treatment of certain voiding dysfunctions. Imipramine has a variety of pharmacological effects including direct antimuscarinic activity, inhibition of catecholamine reuptake, direct muscle relaxant, and calcium antagonism. Using the in-vitro whole bladder model we have studied the effect of imipramine on the rate and magnitude of both intravesical pressure generation and bladder emptying in response to field stimulation. The results can be summarized as follows: at concentrations as low as 1 mumol/l imipramine causes a significant inhibition of volume expulsion without significantly affecting pressure generation. Imipramine produced a dose-dependent inhibition of both pressure development and percent volume emptying; however, it was substantially more potent in inhibiting the ability of the bladder to empty than to generate pressure.

Animals↗
PubMed1987

Nitrofurantoin not surface active agent in rabbit urinary bladder.

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.

Animals↗