Characterization and drug delivery characters of nanocomposite hydrogels based on gamma-radiation copolymerization of poly (vinyl pyrrolidone) (PVP)/sodium alginate (AG)/silver NPs.

Nanocomposite hydrogels were prepared by gamma-radiation copolymerization of poly (vinyl pyrrolidone) (PVP)/sodium alginate (AG) in the presence of silver nanoparticles (Ag NPs). The effect of irradiation dose and Ag NPs content on the gel content and swelling characters of PVP/AG/Ag NPs copolymers was investigated. In addition, the structure-property behavior of the copolymers was characterized by IR spectroscopy, thermogravimetric analysis (TGA) and x-ray diffraction (XRD). The drug uptake-release characters of PVP/AG/silver NPs copolymers, taking Prednisolone as a model drug, were studied. The study showed that the appropriate dose of gamma irradiation to achieve homogeneous nanocomposites hydrogel films and the highest swelling in water was 30 kGy, regardless of composition. The introduction of Ag NPs up to 5 wt % improved the physical properties and enhanced the drug uptake-release characters.

Antibacterial functionalization of cotton and cotton/polyester fabrics applying hybrid coating of copper/chitosan nanocomposites loaded polymer blends via gamma irradiation.

In the present work, copper/chitosan nanocomposites (Cu/CS) were prepared in an aqueous solution in the presence of CS as stabilizer and CuSO4·5H2O precursor. The Cu/CS NPs formation was proved through transmission electron microscopy (TEM), Dynamic light scattering (DLS), Fourier Transform infrared (FT-IR) spectroscopy and XRD diffraction. Cotton and cotton/polyester fabrics were gamma-radiation grafted by padding to pickup of 100%, in nanocomposites based on Cu/CS NPs loaded in polymer blends of poly(vinyl alcohol) (PVA) and plasticized starch (PLST). The grafted fabrics were characterized in terms of tensile mechanical, crease recovery and water absorption properties. The results showed that cotton fabrics displayed higher water absorption (%) than cotton/polyester fabrics for all PVA/PLST compositions and water absorption was found to decrease with increasing the ratio of PVA in the PVA/PLST blends. Cotton/polyester fabrics displays crease recovery angle (CRA) value of 147.6 upon treated with PVA/PLST (80/20%) and gamma irradiated to 30 kGy compared to CRA value of 125.0 for cotton fabrics treated under the same conditions. For cotton fabrics, the tensile strength was largely depends on the irradiation dose, in which the tensile strength of the treated fabric with the different formulations is higher than the untreated fabric. The antimicrobial activity of the fabrics against gram-positive bacteria (Staphylococcus aurous) and gram-negative bacteria (Escherichia coli) was investigated. In case of gram-positive bacteria cotton fabric showed the highest impact, for both 50/50 and 20/80 PVA/PLST of 14 and 14.5 mm inhibition zone, whilst, cotton/polyester fabric recorded 6 and 5 mm inhibition zone against gram-negative bacteria for 50/50 and 20/80 PVA/PLST, respectively.

A New Polyoxygenated Flavonol Gossypetin-3-O-ß-d-Robinobioside from Caesalpinia gilliesii (Hook.) D. Dietr. and In Vivo Hepatoprotective, Anti-Inflammatory, and Anti-Ulcer Activities of the Leaf Methanol Extract.

A hitherto unknown polyoxygenated flavonol robinobioside (gossypetin-3-O-ß-d-robinobioside) was isolated from the leaves of Caesalpinia gilliesii along with thirteen known phenolic secondary metabolites. The isolated compounds were characterized using spectroscopic analysis, including 1D and 2D NMR and mass spectrometry (MS) analyses. The extract reduced the level of liver damage in CCl4-induced liver injury in rats. A decrease of the liver biomarkers-aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and an increase of total antioxidant capacity (TAC) levels-were observed similar to the liver protecting drug silymarin. In addition, the extract showed promising activity against carrageenan-induced paw edema in rats and protected their stomachs against ethanol-induced gastric ulcers in a concentration dependent fashion. The observed activities could be attributed to the high content of antioxidant polyphenols. Our results suggest that the C. gilliesii has the capacity to scavenge free radicals and can protect against oxidative stress, and liver and stomach injury.

Fricke gel dosimeter as a tool in quality assurance of the radiotherapy treatment plans.

Ferrous xylenol gel was evaluated as a dosimeter in verifications of treatment plans for treatments of female breast tumors in external-beam radiation therapy. The dosimeter was calibrated in a cubic wax phantom irradiated with 6 and 15MV beams of an Elekta clinical linear accelerator and then used for measurements of doses in an anthropomorphic phantom of a female torso, which mimicked female breasts after modified radical mastectomy and breast-conserving surgery. Doses measured with the gel in specific locations in the phantom were compared with values predicted by treatment plans created with the XiO treatment planning system (Elekta / IMPAQ) and with results of measurements with an IBA CC13 ionization chamber in the same locations. Differences between the values measured with the gel and predicted by the treatment planning system or measured with the ionization chamber were within 1.5% in most cases. In an area of as steep dose gradient, the difference reached 2.7%, which was explicable in terms of the finite size of the gel dosimeter. The dose response of the gel is dose rate and energy independent in the ranges used in most clinical linacs. The results have shown that ferrous xylenol gels can be used as dosimeters in quality assurance in radiation therapy.

Chemical modification of Aspergillus niger ß-glucosidase and its catalytic properties.

Aspergillus niger ß-glucosidase was modified by covalent coupling to periodate activated polysaccharides (glycosylation). The conjugated enzyme to activated starch showed the highest specific activity (128.5 U/mg protein). Compared to the native enzyme, the conjugated form exhibited: a higher optimal reaction temperature, a lower Ea (activation energy), a higher K m (Michaelis constant) and Vmax (maximal reaction rate), and improved thermal stability. The calculated t 1/2 (half-life) values of heat in-activation at 60 °C and 70 °C were 245.7 and 54.5 min respectively, whereas at these temperatures the native enzyme was less stable (t 1/2 of 200.0 and 49.5 min respectively). The conjugated enzyme retained 32.3 and 29.7%, respectively from its initial activity in presence of 5 mM Sodium Dodecyl Sulphate (SDS) and p -Chloro Mercuri Benzoate ( p -CMB), while the native enzyme showed a remarkable loss of activity (retained activity 1.61 and 13.7%, respectively). The present work has established the potential of glycosylation to enhance the catalytic properties of ß-glucosidase enzyme, making this enzyme potentially feasible for biotechnological applications.

Chemical modification of Aspergillus niger β-glucosidase and its catalytic properties

Aspergillus niger β-glucosidase was modified by covalent coupling to periodate activated polysaccharides (glycosylation). The conjugated enzyme to activated starch showed the highest specific activity (128.5 U/mg protein). Compared to the native enzyme, the conjugated form exhibited: a higher optimal reaction temperature, a lower Ea (activation energy), a higher Km (Michaelis constant) and Vmax (maximal reaction rate), and improved thermal stability. The calculated t1/2 (half-life) values of heat in-activation at 60 °C and 70 °C were 245.7 and 54.5 min respectively, whereas at these temperatures the native enzyme was less stable (t1/2 of 200.0 and 49.5 min respectively). The conjugated enzyme retained 32.3 and 29.7%, respectively from its initial activity in presence of 5 mM Sodium Dodecyl Sulphate (SDS) and p-Chloro Mercuri Benzoate (p-CMB), while the native enzyme showed a remarkable loss of activity (retained activity 1.61 and 13.7%, respectively). The present work has established the potential of glycosylation to enhance the catalytic properties of β-glucosidase enzyme, making this enzyme potentially feasible for biotechnological applications.

Evaluation of noninvasive versus invasive techniques for the diagnosis of Helicobacter pylori infection.

BACKGROUND: Helicobacter pylori is one of the most common bacterial strains causing chronic infections, affecting over one half of the world's population. There is increasing interest in noninvasive methods for diagnosing H. pylori infection. The aim of the study was to evaluate 3 different noninvasive methods of diagnosis: the stool antigen test (HpSA), the serum antibody test, and the stool-polymerase chain reaction (PCR) test as against invasive methods based on histopathologic diagnosis. MATERIALS AND METHODS: Gastric biopsies were obtained during endoscopy. Sections were stained with hematoxylin and eosin and Giemsa stain. Serum samples were tested for H. pylori antibody using an enzyme-linked immnunosorbent assay kit for the semiquantitative determination of IgG antibodies; stool samples were tested for H. pylori antigen using polyclonal enzyme-linked immnunosorbent assay kits. DNA samples from stool specimens were extracted, followed by PCR for the detection of H. pylori UreA. RESULTS: The results revealed that 18/19 (94.7%) patients were positive for H. pylori infection as detected by Giemsa stain, and 84.2% were positive on the basis of hematoxylin and eosin stain, with a sensitivity and specificity of 88.9% and 100%, respectively. Diagnosis by noninvasive methods, including the serum antibody test, revealed a sensitivity and positive predictive value of 88.9% and 94.2%, respectively, whereas the stool antigen test recorded a sensitivity and positive predictive value of 72.2% and 92.9%, respectively. The stool-PCR test recorded a sensitivity of 72.2% and specificity of 100%. CONCLUSIONS: Among the noninvasive methods for diagnosis of H. pylori infection, the 3 methods used in this study recorded promising results, including good sensitivity, which was the highest in the serum antibody test, whereas the stool-PCR test recorded excellent specificity.

Chronic hepatitis c genotype-4 infection: role of insulin resistance in hepatocellular carcinoma.

BACKGROUND: Hepatitis C virus (HCV) is a major cause of chronic hepatitis and hepatocellular carcinoma (HCC) and different HCV genotypes show characteristic variations in their pathological properties. Insulin resistance (IR) occurs early in HCV infection and may synergize with viral hepatitis in HCC development. Egypt has the highest reported rates of HCV infection (predominantly genotype 4) in the world; this study investigated effects of HCV genotype-4 (HCV-4) on prevalence of insulin resistance in chronic hepatitis C (CHC) and HCC in Egyptian patients. METHODS: Fifty CHC patients, 50 HCC patients and 20 normal subjects were studied. IR was estimated using HOMA-IR index and HCV-4 load determined using real-time polymerase chain reaction. Hepatitis B virus was excluded by enzyme-linked immunosorbent assay. Standard laboratory and histopathological investigations were undertaken to characterize liver function and for grading and staging of CHC; HCC staging was undertaken using intraoperative samples. RESULTS: HCC patients showed higher IR frequency but without significant difference from CHC (52% vs 40%, p = 0.23). Multivariate logistic regression analysis showed HOMA-IR index and International Normalization Ratio independently associated with fibrosis in CHC; in HCC, HbA1c, cholesterol and bilirubin were independently associated with fibrosis. Fasting insulin and cholesterol levels were independently associated with obesity in both CHC and HCC groups. Moderate and high viral load was associated with high HOMA-IR in CHC and HCC (p < 0.001). CONCLUSIONS: IR is induced by HCV-4 irrespective of severity of liver disease. IR starts early in infection and facilitates progression of hepatic fibrosis and HCC development.

Systematics of early and middle Miocene Old World monkeys.

New information about the early cercopithecoids Prohylobates tandyi (Wadi Moghra, Egypt) and Prohylobates sp. indet. (Buluk and Nabwal, Kenya) is presented. Comparisons are made among all major collections of Early and Middle Miocene catarrhine monkeys, and a systematic revision of the early Old World monkeys is provided. Previous work involving the systematics of early Old World monkeys (Victoriapithecidae; Cercopithecoidea) has been hampered by a number of factors, including the poor preservation of Prohylobates material from North Africa and lack of comparable anatomical parts across collections. However, it is now shown that basal cercopithecoid species from both northern and eastern Africa can be distinguished from one another on the basis of degree of lower molar bilophodonty, relative lower molar size, occlusal details, symphyseal construction, and mandibular shape. Results of particular interest include: 1) the first identification of features that unambiguously define Prohylobates relative to Victoriapithecus; 2) confirmation that P. tandyi is incompletely bilophodont; and 3) recognition of additional victoriapithecid species.

Histologic study of the tunica albuginea of the penis and mode of cavernosus muscles' insertion in it.

The tunica albuginea (TA) is the outer covering of the corpora cavernosa (CCs) and corpus spongiosum (CS) of the penile shaft. The different histoanatomical patterns of the TA, as well as the mode of attachment of the ischio-/bulbo-cavernosus muscles (ICM, BCM) to the TA, were studied, aiming at elucidating their role in the mechanism of erection. Twenty-eight cadaveric specimens (18 adults, 10 neonatal deaths) were studied morphologically and histologically after staining with hematoxylin and eosin and Verhoeff-van Gieson stains. The TA consisted in 20 specimens of 2 layers: inner circular and outer longitudinal, in 6 specimens of 3 layers: inner circular, longitudinal and outer circular, and in 2 of only one longitudinal layer. The CS TA was formed of one layer of longitudinal fibers. The mode of cavernosus muscles insertion into the TA revealed 3 patterns. The conjoint BCM and ICM formed a fibrous belt over the CCs in 18 specimens, a muscular belt in 6 and no belt in 4. The functional role of the variations in the TA morphological structure is not exactly known. We hypothesize that the 3-layered TA gives more penile rigidity than the double and single layers. Considering the type of cavernosus muscles insertion into the TA, it appears that the fibrous belt exerts more CC compression than the other 2 types of insertion.

Modulation of insulin-like growth factor-I system of the bladder using a somatostatin analogue in chronic spinalized rats.

PURPOSE: We have previously reported the possible role of the insulin-like growth factor-I (IGF-I) system of mitogens in the development of detrusor smooth muscle hyperplasia and hypertrophy after spinal cord injury. We evaluated the in vivo effects of the anti-growth factor somatostatin analogue octreotide on the IGF-I system as well as subsequent changes in bladder smooth muscle hypertrophy and function after spinal cord injury in rats. MATERIALS AND METHODS: Included in this study were 90 adult female Sprague-Dawley rats weighing 200 to 250 gm. Of the rats 18 served as sham operated controls, while the remaining 72 underwent were spinal cord transection at the level of the T10 vertebra. The spinalized animals were randomly divided into 4 equal groups of 18, of which 1 group served as paraplegic controls. The other 3 groups received octreotide (60 microgram. daily for 4 weeks) delivered via a subcutaneously implanted osmotic pump immediately, 2 and 4 weeks after spinal cord injury. At the end of the experiment (6 to 8 weeks) each group of animals was subdivided into 2 subgroups of 9. In the first group filling cystometrography was done, while in the second subgroup wet bladder weight was estimated and Northern blot analysis was performed. RESULTS: Mean wet bladder weight plus or minus standard deviation in sham operated and paraplegic controls was 0.11 +/- 0.01 and 0.64 +/- 0.33 gm., respectively (p <0.05). The increase in bladder weight in paraplegic controls was associated with over expression of the IGF-I gene and with marked suppression of IGF binding proteins-3 and 5 compared with sham operated controls. On the other hand, mean wet bladder weight in the animals that received octreotide immediately after spinal cord injury was 0.17 +/- 0.02 gm., which was associated with a dramatic decrease in IGF-I gene expression and increased expression of IGF binding proteins-3 and 5. Mean cystometric bladder capacity in paraplegic controls was 0.48 +/- 0.18 ml. with an associated voiding pressure of 71 +/- 13 cm. water. All paraplegic controls showed detrusor hyperreflexia. In animals that received octreotide immediately after spinal cord injury mean cystometric bladder capacity was 2.49 +/- 1.75 ml. with an associated voiding pressure of 32 +/- 7 cm. water. Detrusor hyperreflexia disappeared in 88.89% of the rats in this group. There were less marked changes in bladder weight (mean 0.24 and 0.29 +/- 0.3 gm.), IGF-I gene expression and its binding proteins and urodynamic parameters when the drug was given 2 and 4 weeks, respectively, after spinal cord injury. CONCLUSIONS: Modulating the IGF-I system of mitogens in detrusor smooth muscle with consequently decreased bladder hypertrophy and improved urodynamic behavior in spinal cord injured animals using somatostatin analogue could be a possible therapeutic modality in patients with spinal cord injury.

Reduction of bladder outlet resistance by selective stimulation of the ventral sacral root using high frequency blockade: a chronic study in spinal cord transected dogs.

PURPOSE: The use of electrical neural stimulation as treatment for neurogenic bladder is complicated by simultaneous contraction of the striated sphincter. This result is due to the composition of the ventral sacral roots, which contain somatic fibers innervating the external urethral sphincter and preganglionic parasympathetic fibers innervating the detrusor, among others. The somatic fibers have a larger caliber than the parasympathetic fibers and, as large diameter fibers, need a lower stimulus amplitude for activation than smaller fibers. Activation of the smaller fibers is always accompanied by activation of the larger fibers. We studied the effect of chronic application of selective combined low and high frequency current stimulation of the ventral sacral root on bladder evacuation and urethral resistance in chronically spinalized (spinal cord transected above the spinal micturition center) male dogs for daily bladder evacuation. MATERIALS AND METHODS: A total of 14 male mongrel dogs weighing 20 to 25 kg. underwent transection of the spinal cord at the T10 vertebra. The S2 ventral sacral root was wrapped with a bipolar electrode connected to a subcutaneous microstimulator. Daily bladder evacuation by neural stimulation with determination of the voided and residual urine volumes was done for 8 months. The animals were stimulated only with low frequency current during the 1-month spinal shock phase. Selective parameters of combined low frequency stimulation and high frequency blockade currents were subsequently applied for 6 months. For the last study month the animals were again stimulated by low frequency current alone. Bladder and urethral pressure as well as electromyography of the external urethral sphincter and pelvic floor muscles were evaluated monthly. Histopathological testing of the chronically stimulated nerve and external sphincter was performed. RESULTS: Of the 14 dogs 12 completed the followup study. During the shock phase with the application of low frequency only stimulation the animals voided 26% of mean functional bladder capacity with the early return of detrusor activity. Mean detrusor pressure plus or minus standard error of mean was 76.4 +/- 21.6 cm. water, while mean urethral pressure was 83.6 +/- 16.8 cm. water. During the application of selective combined low and high frequency stimulation 7 animals (58%) evacuated the bladder completely with post-void residual urine less than 10% of mean individual functional bladder capacity and 5 (42%) had mean post-void residual urine less than 20% of mean individual bladder capacity. Mean detrusor pressure was 73.5 +/- 20 cm. water and mean urethral pressure was 44 +/- 7.3 cm. water. There was a 45.19% reduction in the mean electromyography activity of the external sphincter. Stimulation of the dogs for the last month by low frequency current resulted in the voiding of 33% of mean bladder capacity with an increase in mean urethral pressure and electromyography activity. CONCLUSIONS: These results of reducing external sphincter activity by the simultaneous application of high frequency current blockade of the somatic fibers and activation of the autonomic fibers of the bladder by low frequency stimulation are promising.

Evidence of a peripheral role of neurokinins in detrusor hyperreflexia: a further study of selective tachykinin antagonists in chronic spinal injured rats.

PURPOSE: Spinal cord injury above the sacral micturition center usually leads to detrusor hyperreflexia, increased intravesical pressure and post-void residual urine. Detrusor hyperreflexia is believed to be mediated by afferent C fibers with tachykinins as neurotransmitters. We investigated the selective peptide tachykinin antagonists MEN 11420 and GR 82334 of NK-2 and NK-1 receptors, respectively, in a chronic rat model of detrusor hyperreflexia after suprasacral spinal cord injury. MATERIALS AND METHODS: Adult female Sprague-Dawley rats weighing 200 to 250 gm. were used. The spinal cord was transected at the T10 level. The bladder was evacuated by the Credé maneuver 3 times daily. After 6 weeks the rats were implanted with femoral vein and bladder dome catheters 2 days before filling cystometry. The 5 rats in group 1 received 100 nmol./kg. of the NK-2 antagonist MEN 11420 intravenously. The 5 rats in group 2 received 100 nmol./kg. of the NK-1 antagonist GR 82334 intravenously. The 5 rats in group 3 received a combination of the same dose of each antagonist. Three repetitive micturition cycles were recorded before injection. Three micturition cycles were done 20 minutes after the injection of each antagonist. Mean cystometric parameters were reported, including bladder capacity, micturition pressure, baseline pressure, post-void residual urine and micturition volume, and the number and amplitude of hyperreflexic contractions greater than 15 cm. water. RESULTS: MEN 11420 significantly reduced the frequency of hyperreflexic contractions and baseline bladder pressure (p <0.05). There was no statistically significant effect on the other cystometric parameters. GR 82334 reduced the amplitude of hyperreflexic contractions but not statistically significant. A combination of MEN 11420 and GR 82334 significantly reduced the frequency and amplitude of hyperreflexic contractions (p <0.05) with no significant effects on other cystometric parameters, although there was a tendency toward increased micturition volume and bladder capacity. CONCLUSIONS: These results suggest that at the peripheral level there is an efferent role of tachykinins in detrusor hyperreflexia after spinal cord injury. NK-1 and NK-2 receptor selective antagonists reduced the frequency and amplitude of hyperreflexic contractions as well as baseline bladder pressure. This finding may lead to potential new therapeutic modalities using selective tachykinins antagonists with other pharmacological agents to combat detrusor hyperreflexia.

Evaluation of the BTA tests for the detection of bilharzial related bladder cancer: the Cairo experience.

OBJECTIVE: To evaluate the clinical performance of the BTA stat test and the BTA TRAK assay in the diagnosis of bilharzia-related bladder cancer and to calculate a new 'Egyptian' cut-off value for the BTA TRAK (quantitative) assay. METHODS: Urine samples of 149 individuals were tested for the presence of the human complement factor H-related protein, the antigen detected by the BTA stat and BTA TRAK tests. The group consisted of 53 healthy volunteers, 20 patients with active bilharziasis, 11 patients with other urologic disorders including prostate cancer, and 65 patients with histologically proven bladder cancer. All samples were obtained prior to surgery or therapy. RESULTS: The BTA stat test was positive in 64 of 65 samples from patients with bladder cancer, for an overall sensitivity of 99%. With a BTA TRAK assay cut-off of 60 U/ml (set at 97% specificity in the healthy population), the sensitivity of the TRAK assay was 94%. There was no statistically significant difference between the sensitivities of the two BTA tests in patients diagnosed with squamous cell carcinoma and those with transitional cell carcinoma. The overall specificity of the BTA stat test was 67% ranging from 15% in patients with bilharziasis to 94% in healthy volunteers. The overall specificity of the TRAK assay was 66%, again with negative results in 15% of the patients with bilharziasis. CONCLUSIONS: The BTA stat test and TRAK tests are extremely sensitive in the detection of bladder cancer in the Egyptian population. Positive results (85%) are also observed in patients with active bilharziasis, which often leads to bladder cancer. Longitudinal follow-up of these positive cases is needed to determine whether these positive results are false or predictive of bladder cancer.

Molluscicidal saponins from Anagallis arvensis against schistosome intermediate hosts.

The molluscicidal activity of saponins isolated from the plant Anagallis arvensis (Primulaceae) was studied against schistosome intermediate hosts, Biomphalaria glabrata and Oncomelania quadrasi. @Strong molluscicidal activity was found in two compounds called desglucoanagalloside B and anagalloside B. Their structures were identified on the basis of chemical and spectroscopic analyses and their activities are comparable to that of the synthetic molluscicide, niclosamide.

Implantable selective stimulator to improve bladder voiding: design and chronic experiments in dogs.

Among the treatments to enhance the bladder voiding, the sacral roots neurostimulation is one of the most promising techniques. The electrostimulation of sacral nerves provokes a simultaneous contraction of the detrusor muscle as well as the external urethral sphincter (EUS). A new simplified-architecture implantable stimulator with its wireless controller have been designed to investigate high-frequency inhibition stimulation strategies. This innovative technique based on high-frequency inhibition reduces sphincter activity during stimulation. Low-frequency current pulses also applied to the sacral roots induces contraction of the detrusor muscle resulting in low pressure voiding. Chronic experiments were carried out on ten male mongrel paraplegic dogs. One cuff electrode was implanted along with each stimulator for eight months. The animals were stimulated twice a day using the prototypes of our implantable selective stimulator while voided and residual urine volume were measured during the procedure. These experiments revealed that the proposed stimulation strategy enhances bladder voiding by more than 50% in comparison with low-frequency only stimulation. The residual urine volume was reduced to an average of 9% and low pressure micturition was achieved as shown by weekly cystourethrogram.

The impact of chronic renal failure on nitric oxide synthase isoforms gene expression in the penis and pelvic ganglia of rats.

PURPOSE: Patients with chronic renal failure experience a variety of physical and metabolic alterations. Uremia is often accompanied by erectile dysfunction (ED). Little information is available concerning the underlying pathophysiological mechanisms by which chronic renal failure can lead to erectile dysfunction. In this study, chronic renal failure was induced by 5/6 nephrectomy in a rat model. Cavernous nerve stimulation was used to measure the intracavernous pressure (ICP) rise. MATERIALS AND METHODS: Adult male Sprague-Dawley rats, aged between 10-12 weeks and weighing 200-250 gm. were divided into two groups. The first group (n = 20) served as a control (sham-operated) and underwent laparotomy with dissection of the perirenal fat around both kidneys. The second group (n = 40) were subjected to an excisional 5/6 nephrectomy (unilateral nephrectomy and contralateral upper and lower polar nephrectomy). Serum creatinine was measured 3 days post-operatively and at the end of the 12th week. Development of renal failure was considered if the animal had serum creatinine more than 120 microM/l. After 12 weeks, 10 animals per group were subjected to electric field stimulation (EFS) of the cavernous nerve with simultaneous recording of ICP-rise and systemic blood pressure. Northern and western blot analyses were used to determine the mRNA expression and protein contents of NOS isoforms (neuronal and endothelial) in the penile tissues and MPG. RESULTS: This remnant kidney model resulted in renal failure in 20 of 40 animals. The ICP-rise after cavernous nerve stimulation in the renal failure group was significantly impaired, 7.7+/-2.9 cm. H2O, as compared to control rats, 55.5+/-1.2 cm. H2O (p<0.001). The latency period after cavernous nerve stimulation was significantly increased in renal failure rats (6.9+/-0.95 sec.) in comparison to controls (2.4+/-0.25 sec.). Six of ten uremic animals had significantly lower testosterone (<1 nmol./l.) levels compared to non-uremic rats (3.6 nmol./l.) (p<0.005). Northern blot analysis revealed that renal failure rats had significantly higher levels of nNOS mRNA in the MPG and penile tissues than controls. There was no change in eNOS mRNA in either group. Western blot analysis demonstrated that eNOS and nNOS protein contents in the MPG and penile tissues of renal failure rats were significantly higher than those of controls. CONCLUSION: This report demonstrates that impairment of erection in renal failure rats, as determined by ICP-rise, was present in spite of elevated neuronal nitric oxide synthase mRNA and its protein in the MPG and penile tissues. Further studies are needed to determine whether erectile dysfunction is a result of post-translational changes, circulating inhibitory substances or other factors.

Alteration of the insulin-like growth factor system of mitogens in hyperplastic bladders of paraplegic rats.

PURPOSE: Smooth muscle cells of the bladder retain the ability to proliferate in response to injury or mechanical stimulation. Insulin-like growth factor (IGF) I is a mitogenic and hypertrophic agent for smooth muscle cells. The purpose of this study is to examine if spinal cord injury could lead to bladder hypertrophy via the IGF system. MATERIALS AND METHODS: The study involved spinal cord transection of female Sprague Dawley rats (approximately 250 to 300 gm.). Six weeks following surgery the urinary bladder was collected. Northern and Western blotting, and IGF-I receptor (IGF-IR) affinity labeling were used to determine the expression of the IGF system, IGFBP levels, and IGF-IR levels respectively. RESULTS: Chronic spinal cord injury leads to an increase in the wet weight of the bladder and in the level of proliferation cell nuclear antigen expression. IGF-I mRNA levels increase, while IGFBP 3 and 5 mRNA and protein levels dramatically decrease. The gene expression of IGFBP 2 and 4 varies from rat to rat, and IGF-IR expression slightly increases. CONCLUSION: Our results suggest that following spinal cord injury, overexpression of IGF-I and underexpression of IGFBP 3 and 5 may lead to hyperplasia of the smooth muscle layer of the bladder.

Experimental Chronic Renal Failure-Associated Erectile Dysfunction: Molecular Alterations in Nitric Oxide Synthase Pathway and IGF-I System.

Chronic renal failure causes wide-ranging disturbances in male erectile function, and the dysfunction usually is not corrected by hemodialysis. In this study, erectile function and expression of nitric oxide synthase (NOS) isoforms, insulin-like growth factor-I (IGF-I), and IGF-I binding proteins were assessed in rats in which uremia had been produced by 5/6 nephrectomy. In the animals that suffered renal failure, there was a significantly lower rise in intracavernosal pressure in response to electrical stimulation, and the mean patency period after cavernous nerve stimulation was significantly increased. The amount of neuronial NOS mRNA was significantly higher in the penile tissues and major pelvic ganglia (MPG) of uremic rats than in control animals. There consistently were higher levels of nNOS and endothelial NOS in the penile tissues and MPG of rats with renal failure, and there was a significant decrease in the amount of IGF-I gene expression in the MPG of these animals. Expression of the IGF binding proteins 2 and 4 but not 5 also was reduced. This preliminary work demonstrates that impairment of erection in chronic renal failure in the rat is attributable to a disturbance in NOS gene expression with concomitant changes in IGF-I. These discoveries may permit an improved therapeutic approach to men with erectile dysfunction associated with chronic renal failure.

Implantable stimulation system dedicated for neural selective stimulation.

A functional electrical stimulation system is presented, which is dedicated for the selective neural stimulation of the bladder. The proposed system is composed of an internal stimulator (implant) and an external controller. The system is used to produce low-pressure voiding of the bladder in spinal cord injured patients. The implant is powered and operated by the external controller via radio-frequency electromagnetic coupling. All stimulation parameters are chosen externally using the controller and are sent to the implant, which produces the desired stimuli. These stimuli are applied directly to the S2 nerve which is linked to the sphincter and bladder muscles. A high-frequency signal is used to inhibit the contraction of the sphincter muscle, and low-frequency pulses stimulate the bladder muscle (the detrusor). Dedicated computer software is used by the physician to select the optimal parameters for each patient and to activate the implant through a parallel port interface with built-in transmitter. The parameters are then transferred to a hand-held controller which is used by the technical staff and by the patients themselves. Acute studies have been performed to validate the selective stimulation strategy, and chronic experimentation is currently underway in dogs.