Does Hypertension Affect the Recovery of Renal Functions after Reversal of Unilateral Ureteric Obstruction?

Research has demonstrated that hypertension can lead to an exaggeration in the renal functional and histological changes caused by ureteral obstruction. These changes were particularly observed shortly after the release of a relatively brief period of unilateral ureteral obstruction (UUO). However, the long-term impact of hypertension on the recovery of renal functions has not been investigated beyond the immediate period after UUO reversal. In order to investigate this effect, a group of spontaneously hypertensive rats (G-SHR, n = 11) and a group of normotensive Wistar Kyoto rats (G-NTR, n = 11) were subjected to a 48 h reversible left UUO. The impact of UUO was then examined 45 days after the reversal of obstruction. The glomerular filtration rate, renal blood flow, and the fractional excretion of sodium in the post-obstructed left kidney (POK) showed similarities to the non-obstructed right kidney (NOK) in both groups. However, the changes in the albumin creatinine ratio, renal injury markers, pro-apoptotic markers, and histological changes in the G-SHR were much more pronounced compared to the G-NTR. We conclude that hypertension continues to have a significant impact on various aspects of renal injury and function, even several weeks after UUO reversal.

N-(2-hydroxy phenyl) acetamide ameliorate inflammation and doxorubicin-induced nephrotoxicity in rats.

Doxorubicin (DOX) is an anthracyclin antibiotic used for the treatment of various cancers. Nephrotoxicity is among the serious side effects of DOX, therefore, DOX-induced nephrotoxic model has been widely used to study nephropathies. The objectives of this study is to investigate the possible anti-inflammatory and nephroprotective effects of salicylic acid derivative, N-(2-hydroxy phenyl) acetamide (NA-2), in a rat model of DOX-induced nephrotoxicity. The in vitro anti-inflammatory potential of NA-2 was manifested by whole blood oxidative burst and nitric oxide (NO) assays with no toxicity on normal human fibroblast (BJ) cells, human embryonic kidney (HEK-293) cells, and normal monkey kidney epithelial (Vero) cells. The in vivo study included five groups: Normal control, DOX (6 mg/kg DOX-i.v.via tail vein), NA-2 treated control-i.p., NA-2/DOX treated-i.p., and prednisolone/DOX treated. After 7 days of DOX administration, rats with urinary protein level of >50 mg/kg/day were selected. Treatment group rats received i.p. doses of NA-2 (10 mg/kg/day) for 3 weeks with weekly monitoring of urinary protein excretion and body weights. mRNA expression of interleukin (IL)-1ß, IL-6, tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1, and kidney injury molecule (KIM)-1 was analyzed by quantitative polymerase chain reaction (qPCR). Protein expressions were analyzed by immunohistochemistry. NA-2 attenuated DOX-induced changes in serum and urine levels, and improved inflammatory profile of the renal tissue. Histopathological findings revealed protective effects of NA-2 showing lesser lesions. We conclude that NA-2 is able to protect against DOX-induced renal damage functionally, biochemically and histopathologically with corresponding improvement in the kidney inflammatory profile.

The Effect of Hypertension on the Recovery of Renal Dysfunction following Reversal of Unilateral Ureteral Obstruction in the Rat.

Both ureteral obstruction (UO) and hypertension are common conditions that affect kidney functions. Hypertension and chronic kidney disease are closely associated with an overlapping and intermingled cause-and-effect relationship. The effect of hypertension on the renal dysfunction following reversible UO has not been studied previously. To study this effect, spontaneously hypertensive (G-HT, n = 10) and normotensive Wistar (G-NT, n = 10) rats underwent 48-h reversible left unilateral UO (UUO), and the effect of UUO was studied 96 h following UUO reversal. The glomerular filtration rate, renal blood flow, and renal tubular functions such as the fractional excretion of sodium in the post-obstructed left kidney (POK) in both groups were significantly altered compared with the non-obstructed right kidney (NOK). However, the alterations in the G-HT were significantly more exaggerated when compared with the G-NT. Similar findings were observed with the histological features, gene expression of kidney injury markers, pro-inflammatory, pro-fibrotic and pro-apoptotic cytokines, and pro-collagen, as well as tissue levels of apoptotic markers. We conclude that hypertension has significantly exaggerated the alterations in renal functions and other parameters of renal injury associated with UUO.

The Effect of Nerolidol Renal Dysfunction following Ischemia-Reperfusion Injury in the Rat.

Efforts to decrease the deleterious effects of renal ischemia-reperfusion injury (IRI) are ongoing. Recently, there has been increasing interest in using natural phytochemical compounds as alternative remedies in several diseases. Nerolidol is a natural product extracted from plants with floral odors and has been proven to be effective for the treatment of some conditions. We investigated the effect of nerolidol in a rat model of renal IRI. Nerolidol was dissolved in a vehicle and administered orally as single daily dose of 200 mg/kg for 5 days prior to IRI and continued for 3 days post IRI. G-Sham (n = 10) underwent sham surgery, whereas G-IRI (n = 10) and G-IRI/NR (n = 10) underwent bilateral warm renal ischemia for 30 min and received the vehicle/nerolidol, respectively. Renal functions and histological changes were assessed before starting the medication, just prior to IRI and 3 days after IRI. Nerolidol significantly attenuated the alterations in serum creatinine and urea, creatinine clearance, urinary albumin and the urinary albumin-creatinine ratio. Nerolidol also significantly attenuated the alterations in markers of kidney injury; proinflammatory, profibrotic and apoptotic cytokines; oxidative stress markers; and histological changes. We conclude that nerolidol has a renoprotective effect on IRI-induced renal dysfunction. These findings might have clinical implications.

Preparation and Characterization of Blank and Nerolidol-Loaded Chitosan-Alginate Nanoparticles.

Recently, there has been a growing interest in using natural products as treatment alternatives in several diseases. Nerolidol is a natural product which has been shown to have protective effects in several conditions. The low water solubility of nerolidol and many other natural products limits their delivery to the body. In this research, a drug delivery system composed of alginate and chitosan was fabricated and loaded with nerolidol to enhance its water solubility. The chitosan-alginate nanoparticles were fabricated using a new method including the tween 80 pre-gelation, followed by poly-ionic crosslinking between chitosan negative and alginate positive groups. Several characterization techniques were used to validate the fabricated nanoparticles. The molecular interactions between the chitosan, alginate, and nerolidol molecules were confirmed using the Fourier transform infrared spectroscopy. The ultraviolet spectroscopy showed an absorbance peak of the blank nanoparticles at 200 nm and for the pure nerolidol at 280 nm. Using both scanning and transmission electron microscopy, the nanoparticles were found to be spherical in shape with an average size of 12 nm and 35 nm for the blank chitosan-alginate nanoparticles and the nerolidol-loaded chitosan-alginate nanoparticles, respectively. The nanoparticles were also shown to have a loading capacity of 51.7% and an encapsulation efficiency of 87%. A controlled release profile of the loaded drug for up to 28 h using an in vitro model was also observed, which is more efficient than the free form of nerolidol. In conclusion, chitosan-alginate nanoparticles and nerolidol loaded chitosan-alginate nanoparticles were successfully fabricated and characterized to show potential encapsulation and delivery using an in vitro model.

The effect of neprilysin and renin inhibition on the renal dysfunction following ischemia-reperfusion injury in the rat.

The natriuretic peptide (NP) system counter-regulates the renin-angiotensin system (RAS), so enhancing the activity of natriuretic peptides (NPs) may be beneficial in conditions when RAS is activated such as ischemia-reperfusion injury (IRI). Neprilysin is the key enzyme responsible for the degradation of NPs. The effects of neprilysin inhibition or the combination of neprilysin inhibition and RAS inhibition on renal IRI-induced renal dysfunction have not been investigated yet. To investigate this, rats underwent sham surgery or bilateral IRI for 20 min. G-Als, G-Scb, and G-Als+Scb underwent similar protocol but received aliskiren (renin inhibitor), sacubitril (neprilysin inhibitor) or a combination of both pre- and post-IRI, respectively. IRI caused significant alterations in all renal functional parameters, markers of acute renal injury, pro-inflammatory and pro-fibrotic cytokines, and histological features. All these alterations were significantly attenuated in G-Als, G-Scb, and G-Als+Scb. The attenuations in the alterations in serum creatinine, creatinine clearance, and histological features were larger in G-Als+Scb compared to either G-Als or G-Scb. We conclude that RAS blockade by a renin inhibitor (aliskiren) or neprilysin inhibition by sacubitril separately led to significant attenuation in the renal IRI-induced renal dysfunction. The combination of aliskiren and sacubitril was more effective than either one alone.

Despite initial recovery of GFR, long-term renal functions deteriorate following short periods of unilateral ureteral obstruction.

Following the release of short periods of unilateral ureteral obstruction (UUO), glomerular filtration rate (GFR) recovers by time. However, research in experimental animal models has demonstrated the presence of an ongoing element of renal interstitial fibrosis a few weeks following UUO reversal. Interstitial fibrosis can cause deterioration in GFR, and it is not known whether it leads to an ongoing slow deterioration in other renal functions despite the apparent initial recovery postreversal. To investigate this, rats underwent a 72-h reversible UUO. Renal functions of nonobstructed and previously obstructed kidneys were measured 1, 4, and 18 mo postreversal. GFR in nonobstructed and previously obstructed kidneys was similar up to 18 mo postreversal. However, there was ongoing tubulointerstitial fibrosis, and the degree of tubular atrophy and dilatation deteriorated by time. This was associated with an increase in urinary albumin leakage and alterations in renal injury markers, proinflammatory and profibrotic cytokines, and p53 from 4 mo onward despite the recovery in GFR. In conclusion, several aspects of renal functions continue to deteriorate following reversal of relatively short periods of UUO despite the initial recovery in GFR. This might stimulate further research in this area and might have clinical implications in terms of determining the best time for intervention following acute ureteral obstruction and long-term monitoring of these individuals.

The Effect of Arabic Gum on Renal Function in Reversible Unilateral Ureteric Obstruction.

Arabic gum (AG) has antioxidant and anti-inflammatory properties. However, the effect of AG in ureteric obstruction (UO) has not been investigated yet. Male rats underwent reversible left unilateral UO (UUO) for 72 h. Group AG-1 (n = 12) received AG 15 g/kg/day dissolved in drinking water starting seven days before and continuing throughout the period of the UUO, whereas group Vx-1 (n = 8) had only water. Group AG-2 (n = 12) and Vx-2 (n = 8) had similar protocols as AG-1 and Vx-1, respectively, but underwent terminal experiments to measure renal functions, six days post-UUO reversal. Arabic gum significantly attenuated the UUO-induced increase in the tissue level of malonedialdehyde and superoxide dismutase and the rise in the gene expression of TNF-α, TGF-ß1, and p53 in AG-1 compared to Vx-1. It also attenuated the severity of tubular dilatation. However, AG did not affect the alterations in the renal blood flow or glomerular filtration rate. The fractional sodium excretion was lower in AG-2 but did not reach statistical significance (0.40 ± 0.11 vs 0.74 ± 0.12, p = 0.07). AG attenuated the UUO-induced rise in oxidative stress markers and proinflammatory and profibrotic cytokines and the degree of renal tubular dilatation, indicating a protective effect in obstructive nephropathy.

Effect of diabetes mellitus on the recovery of changes in renal functions and glomerular permeability following reversible 24-hour unilateral ureteral obstruction.

BACKGROUND: Following reversal of short periods of ureteral obstruction (UO), glomerular and tubular renal dysfunction recovers with time. Diabetes mellitus (DM) affects glomerular function; thus, the ability of diabetic kidneys to recover from UO may be impaired. This study investigated the effects of long-term DM on the recovery of glomerular and tubular function, as well as permeability of the glomerular filtration barrier (GFB), after unilateral UO (UUO) reversal. METHODS: Diabetes mellitus was induced in Wistar rats by intraperitoneal streptozotocin. All diabetic and age-matched control rats underwent reversible 24-hour left UUO. The renal function of both kidneys was measured using clearance techniques 3 hours and 7 and 30 days after UUO reversal. Glomerular permeability was assessed by measuring the glomerular sieving coefficients for fluorescein isothiocyanate-conjugated Ficoll (molecular radius: 20-90 Å). RESULTS: Unilateral UO induced transient changes in the size selectivity of GFB small pores. However, the size selectivity function of large pores had not returned to baseline even 30 days after UUO reversal. Diabetes mellitus caused exaggerated early alterations in glomerular hemodynamic and tubular function, as well as size selectivity dysfunction of both small and large pores. At 30 days after UUO reversal, despite glomerular hemodynamic and tubular function and the size selectivity of small pores returning to normal in both diabetic and non-diabetic rats, the residual size selectivity dysfunction of large pores was more severe in diabetic rats. CONCLUSION: Unilateral UO caused long-term dysfunction in the size selectivity of large pores of the GFB. In addition, DM significantly exaggerated this dysfunction, indicating a more ominous outcome in diabetic kidneys following UUO.

Alda-1, an aldehyde dehydrogenase-2 agonist, causes deterioration in renal functions following ischemia-reperfusion injury due to crystalline nephropathy.

Renal ischemia-reperfusion injury (IRI) induces the production of aldehydes which are detoxified by aldehyde dehydrogenases (ALDHs). Alda-1 is a selective ALDH2 agonist and its protective effect was demonstrated in several conditions. The effect of Alda-1 on the kidney or on renal IRI was not investigated. We investigated the effect of Alda-1 on the renal dysfunction following IRI. Wistar rats underwent left IRI for 40 min. Group-Alda (n = 11) received Alda-1 starting 24 h before IRI and continued for 7 days thereafter when renal functions were measured. Group-Vx (n = 11) underwent similar protocol but received the dissolvent. Alda-1 did not affect renal blood flow or glomerular filtration rate in the left ischemic kidney in Group-Alda compared to Group-Vx (3.05 ± 0.50 vs. 3.53 ± 0.70, and 0.40 ± 0.06 vs. 0.51 ± 0.08, respectively, p > .05 for both). However, left renal fractional sodium excretion was higher in Group-Alda (2.80 ± 0.43 vs. 1.37 ± 0.36, p = .02). Alda-1 also adversely affected the gene expressions of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin (217 ± 38 vs. 99 ± 13 and 49 ± 13 vs. 20 ± 5, respectively, p < .05 for both) and the alterations in tumor necrosis factor-α, transforming growth factor-ß1, plasminogen activator inhibitor-1, fibronectin 1 and p53 (4.4 ± 0.9 vs. 2.1 ± 0.3, 1.5 ± 0.1 vs. 1.1 ± 0.1, 30.0 ± 2.7 vs. 11.7 ± 2.3, 3.6 ± 0.4 vs. 2.1 ± 0.2 and 1.3 ± 0.1 vs. 0.9 ± 0.07, respectively, p ≤ .05 for all). This was associated with intratubular crystal deposition suggestive of crystalline nephropathy. Alda-1 exacerbated the IRI-induced renal tubular dysfunction and alterations in markers of acute kidney injury, biomarkers of inflammation, fibrosis and apoptosis and this was associated with intratubular crystal deposition suggestive of crystalline nephropathy.

Does ß-caryophyllene protect against renal dysfunction following ischemia-reperfusion injury in the rat?

INTRODUCTION: Renal ischemia-reperfusion injury (IRI) causes renal functional alterations which may lead to permanent renal impairment. ß-caryophyllene (BCP), a natural bicyclic sesquiterpene, is an important constituent of many edible plants including spices. It is an FDA-approved food additive which possesses potent anti-inflammatory and antioxidant activities and has been shown to protect against chemotherapeutics-induced organ toxicities and against ischemic injuries to heart, liver and brain. Oxidative stress and inflammation is a main accompaniment of renal dysfunction, however, the effect of BCP on IRI-induced renal dysfunction has not been investigated yet and therefore the aim of this study was to investigate the effect of BCP on IRI-induced renal dysfunction. METHODS: Wistar rats underwent left renal warm ischemia for 40 minutes. G-BCP (n=13) received oral BCP (50 mg/kg/day) dissolved in a vehicle starting 7 days prior to IRI and continued 7 days thereafter when the renal functions of both kidneys and the markers of oxidative stress and pro-inflammatory cytokines were measured. G-Vx (n=13) underwent similar protocol but received vehicle only. RESULTS: IRI affected hemodynamic (renal blood flow and glomerular filtration rate) and tubular (urine volume, total and fractional urinary sodium excretion) parameters in the left ischemic kidney in G-Vx. Though, BCP did not affect any of these alterations in the ischemic kidney (P>0.05 for all). However, it attenuated the alterations in malondialdehyde (MDA) and glutathione (GSH) in the left ischemic kidney in G-BCP compared to G-Vx (9.3±2.1 vs. 4.8±1.0, P=0.047 and 18.1±2.5 vs. 13.6±1.7, P=0.09, respectively). CONCLUSION: Our study results demonstrate that BCP attenuated the alterations in some of the oxidative stress markers. However, these were not translated in to the protective effects on the haemodynamic and tubular glomerular functions when measured seven days post-IRI. This suggests that BCP has a weak reno-protective effect under ischemic conditions.

The effect of epigallocatechin-3-gallate on the renal dysfunction in the obstructed kidney in the rat.

INTRODUCTION: Epigallocatechin-3-gallate (EGCG) is the most active catechin polyphenol extracted from the green tea. EGCG has protective effects in various renal and non-renal conditions. The aim of this study was to investigate the effect of EGCG on the alterations in renal functional parameters following reversible unilateral ureteral obstruction (UUO) in the rat. METHODS: Wistar rats underwent reversible left UUO for 72 hours. Group-EGCG (n=10) received intraperitoneal 50 mg/kg/day of EGCG whereas Group-Vx (n=10) had only normal saline. Five days post UUO reversal, renal functions of both kidneys were measured using clearance techniques and the gene expression of some of kidney injury markers (KIM-1 and NGL) and the pro-inflammatory mediator (TNF-α) were determined using real time PCR. RESULTS: Renal blood flow, glomerular filtration rate, urine volume and urinary sodium excretion were still altered 5 days post-UUO reversal. Fractional sodium excretion had returned to baseline values by that time. EGCG did not significantly affect any of the renal functional parameters of the obstructed kidney (P>0.05 for all). However, it significantly decreased the gene expressions of KIM-1, NGAL and TNF-α in the left obstructed kidney in Group-EGCG compared to Group-Vx (28±27 vs. 286±107, 1.1±0.2 vs. 10.9±4.3, and 0.8±0.1 vs. 1.5±0.2, P<0.05 for all). CONCLUSION: EGCG appears to have no significant protective effect on the haemodynamic or tubular glomerular functions when measured as early as five days post reversal of UUO despite the attenuation of some of the kidney injury markers and pro-inflammatory mediators.

The effect of aliskiren on the renal dysfunction following unilateral ureteral obstruction in the rat.

PURPOSE: To investigate the effect of blocking renin-angiotensin system by direct renin inhibition using aliskiren on the renal dysfunction following reversible unilateral ureteral obstruction (UO). METHODS: Wistar rats underwent reversible left UO for 72 hours. Group-Alsk (n=12) received aliskiren (30 mg/kg/day) dissolved in water starting one day before creating UO and continued until the terminal experiment five days post reversal when renal functions were measured using clearance techniques. Group-Vx (n=12) underwent similar protocol but had water only. Gene expression analysis of some markers of kidney injury was measured using PCR technique. RESULTS: In Group-Vx, renal blood flow (RBF) and glomerular filtration rate (GFR) in the left kidney were significantly lower than the right kidney (1.82±0.12 vs. 3.19±0.40, P=0.001 and 0.81±0.08 vs. 1.44±0.09, P=0.004, respectively). However, left fractional excretion of sodium (FENa) was higher than the right FENa (0.80±0.15 vs. 0.55±0.04, P=0.05). Comparing the left obstructed kidney in Group-Alsk vs. Group-Vx, RBF and GFR were higher in Group-Alsk (2.44±0.30 vs. 1.82±0.12, P=0.049 and 1.02±0.11 vs. 0.81±0.08, P=0.07, respectively). The left renal FENa was lower in Group-Alsk but did not reach statistical significance (0.54±0.07 vs. 0.80±0.15, P=0.07). Aliskiren also decreased the gene expressions of NGAL, KIM-1 and p53. CONCLUSION: Direct renin inhibition by aliskiren appears to have protective effect on the renal dysfunction and on the markers of renal injury following UO indicating a potential clinical benefit of this agent. Further, this data and the previous studies indicate that blocking renin-angiotensin system at any level has a protective effect in obstructive nephropathy.

The effect of thymoquinone on the renal functions following ischemia-reperfusion injury in the rat.

INTRODUCTION: The aim of this study was to investigate the effect of thymoquinone, an antioxidant phytochemical compound found in the plant Nigella sativa, on the alterations in renal functional parameters following warm renal ischemia-reperfusion injury (IRI) in the rat. METHODS: Wistar rats underwent left renal ischemia for 35 minutes. Group-TQ (n=15) received thymoquinone 10 mg/kg/day (dissolved in a vehicle (corn oil) orally by gavage starting 4 days prior to IRI and continued 6 days thereafter when the hemodynamic and tubular renal functions of the right and left kidneys were measured using clearance techniques. Group-Vx (n=15) underwent similar protocol but received only the vehicle. RESULTS: IRI affected all hemodynamic and tubular parameters in the affected kidney. Thymoquinone attenuated the IRI-related alteration in renal functions so when the left ischemic kidney in Group-TQ and Group-Vx were compared, the left RBF and GFR were significantly higher in Group-TQ (2.02±0.39 vs. 1.27±0.21, P=0.04 and 0.33±0.08 vs. 0.18±0.03, P=0.03, respectively). Thymoquinone also improved left renal FENa (1.59±0.28 vs. 2.40±0.35, P=0.04). In addition, it decreased the gene expressions of KIM-1, NGAL, TNF-α, TGF-ß1 and PAI-1 (143±20 vs. 358±49, 16±3 vs. 34±6, (1.1±0.2 vs. 2.8±0.4, 1.6±0.1 vs. 2.8±0.1, and 2.4±0.3 vs. 5.8±1.0, P<0.05 for all). CONCLUSION: Thymoquinone ameliorated the IRI effect on the hemodynamic and tubular renal functional parameters as well as the expression of some kidney injury markers and pro-inflammatory and pro-fibrotic cytokines indicating a renoprotective effect of this agent on the IRI-induced renal dysfunction with potential clinical implications.

Reduced glomerular size selectivity in late streptozotocin-induced diabetes in rats: application of a distributed two-pore model.

Microalbuminuria is an early manifestation of diabetic nephropathy. Potential contributors to this condition are reduced glomerular filtration barrier (GFB) size- and charge selectivity, and impaired tubular reabsorption of filtered proteins. However, it was recently reported that no significant alterations in charge selectivity of the GFB occur in early experimental diabetic nephropathy. We here aimed at investigating the functional changes in the GFB in long-term type-1 diabetes in rats, applying a novel distributed two-pore model. We examined glomerular permeability in 15 male Wistar rats with at least 3 months of streptozotocin (STZ)-induced diabetes (blood glucose ∼20 mmol/L) and in age-matched control rats. The changes in glomerular permeability were assessed by determining the glomerular sieving coefficients (θ) for FITC-Ficoll (molecular radius 20-90 Å) using size exclusion HPLC. The values of θ for FITC-Ficoll of radius >50 Å were significantly increased in STZ-diabetic rats compared to age-matched controls (θ for 50-69 Å = 0.001 vs. 0.0002, and θ for 70-90 Å = 0.0007 vs. 0.00006, P < 0.001), while θ for FITC-Ficoll <50 Å tended to be lower in diabetic rats than in controls (θ for 36-49 Å = 0.013 vs. 0.016, ns). According to the distributed two-pore model, there was primarily an increase in macromolecular transport through large pores in the glomerular filter of diabetic rats associated with a loss of small-pore area. Deterioration in the glomerular size selectivity due to an increase in the number and size-spread of large pores, with no changes in the permeability of the small-pore system, represent the major functional changes observed after 3 months of induced experimental diabetes.

Propagation characteristics of the electrical impulse in the normal and obstructed ureter as determined at high electrophysiological resolution.

OBJECTIVE: To investigate the propagation of the electrical impulses in a unilateral ureteric obstruction model using a high-resolution technique in vivo. MATERIALS AND METHODS: In Wistar rats (n= 15), the left mid-ureter was occluded and the electrical activity was recorded from the proximal and distal part of the obstructed ureter and from the right ureter at different times up to 2 weeks post-obstruction using 64 extracellular electrodes. RESULTS: In the left ureter, impulses propagated in an antegrade direction at a frequency of 15.5 ± 1.3/min and a velocity of 1.6 ± 0.1 cm/s. Immediately post-obstruction, the proximal part showed an increase in frequency (19.1 ± 2.5/min; P < 0.05) followed by a gradual decrease (at 2 weeks: 2.5 ± 1.2/min; P < 0.001). The velocity of these impulses decreased gradually (at 2 weeks: 0.5 ± 0.1 cm/s; P < 0.05). Distally, the antegrade propagations gradually disappeared and, at 1 week, 33% of ureters showed retrograde impulses and 67% displayed no electrical activity. The frequency of both antegrade and retrograde impulses distal to the obstruction dropped immediately after obstruction so that, at 1 day, it was 1.0 ± 0.3 and 1.5 ± 0.2/min, respectively (P < 0.01 for both). The velocity of these antegrade and retrograde impulses showed a significant rise throughout the post-obstruction period. The right ureter showed only a transient increase in frequency from 18.7 ± 2.7 to 30.3 ± 6.1/min (P < 0.05). CONCLUSIONS: Using this high-resolution technique, it is concluded that, after ureteric obstruction, there were immediate and significant changes in the propagation of electrical impulses in the proximal and distal left ureter and in the right ureter, all of which behaved differently. This data may provide a better insight into the electrophysiological function of the normal and obstructed ureter.

Propagation of the electrical impulse in reversible unilateral ureteral obstruction as determined at high electrophysiological resolution.

PURPOSE: We investigated the propagation of electrical impulses in a reversible, complete or partial unilateral ureteral obstruction model in vivo. MATERIALS AND METHODS: In Wistar rats the left mid ureter was completely (8) or partially (7) occluded and released after 24 hours. We recorded electrical activity of the left and right ureter before, during and after obstruction at different stages up to 2 weeks after obstruction using a high resolution, 64 extracellular electrode probe. RESULTS: Complete obstruction in the left proximal ureter caused an immediate increase in frequency from a mean ± SEM of 14.8 ± 1.3 to 18.6 ± 1.7 per minute (p <0.05), followed by a 1.4 ± 0.9 per minute decrease (p <0.001). Within the first 2 days after reversal velocity gradually decreased from 1.82 ± 0.12 to 0.79 ± 0.17 cm per second (p <0.001). Release of obstruction gradually restored frequency and velocity, which returned to baseline at 2 weeks. Generally the alterations in rats with complete and partial obstruction were similar but they were less marked in those with partial obstruction. Distal to the obstruction site the impulses disappeared (38%) or propagated retrograde (43%) at some stage in the post-obstruction period. These abnormal impulse propagations also gradually disappeared in the post-obstruction stage. CONCLUSIONS: After complete or partial ureteral obstruction there were immediate, significant changes in the propagation of electrical impulses in the proximal and distal left ureter, which were generally less marked after partial than after complete obstruction. Reversal of obstruction resulted in the gradual disappearance of this abnormality in 2 weeks.

First successful autologous chondrocyte implantation in Pakistan.

Osteochondritis dissecans entails a hyaline cartilage defect of the articular surface causing pain and functional restriction in young adults, sometimes resulting in early degenerative arthritis. Conventional treatment methods such as abrasion chondroplasty and mosaicplasty have limitations in terms of quality of the resultant cartilage and donor site morbidity. A more recent technique, autologous chondrocyte implantation (ACI) results in hyaline cartilage formation and gives good long-term outcome, but requires a high-level cell culture facility and two surgical procedures. The patient was a young female with knee pain, intermittent locking and feeling of "joint mouse". MRI scan and arthroscopy showed a 2 x 2 cm full thickness osteochondral defect in the medial femoral condyle. A free fragment of articular cartilage was found, which was extracted arthroscopically, and chondrocytes were cultured from it in the Juma laboratory. Subsequently, patient underwent surgery whereby the chondrocytes were injected under a periosteal patch sewn over the defect. Over six months, patient's symptoms completely resolved and she returned to full function. A repeat arthroscopy after one year revealed complete filling of the previous defect with normal appearing cartilage indicating success of the procedure. This technology can be utilized for treating patients with a variety of conditions affecting hyaline cartilage of joints.