Anti-tuberculosis activity of morusin: a promising flavonoid from white mulberry.

BACKGROUND: TB has remained a significant public health concern from historical times to the present day. Each year, growing drug resistance problems necessitate the discovery of new drugs and drug precursors for TB treatment. Morusin is an important flavone found in the bark of white mulberry (Morus alba L.) with anti-oxidant, antimicrobial, anti-tumour, anti-inflammatory and antiallergic activity.OBJECTIVE: To determine the anti-TB efficacy of morusin on Mycobacterium tuberculosis strains.DESIGN: Anti-TB efficacy of morusin was tested on H37Ra (American Type Culture Collection [ATCC] 25177), H37Rv (ATCC 27294), ATCC 35822 (isoniazid [INH] resistant), ATCC 35838 (rifampicin [RIF] resistant), and ATCC 35820 (streptomycin [SM] resistant) standard strains and its efficacy was determined using nitrate reductase assay (NRA).RESULTS: The minimum inhibitory concentration (MIC) of morusin was tested in the range of 53.83â-"0.21 λg/ml. The MIC for H37Ra (ATCC 25177), H37Rv (ATCC 27294) and ATCC 35838 (RIF-resistant) strains were found to be 6.72 λg/ml, and this was 13.45 λg/ml for the ATCC 35822 (INHresistant) and ATCC 35820 (SM-resistant) strains.CONCLUSION: To consider morusin as a viable alternative or precursor drug for TB treatment, it is imperative to conduct an exhaustive examination of its mechanism of action and conduct in vitro studies using clinical isolates.

Regiospecific Oxidation of Chlorobenzene to 4-Chlororesorcinol, Chlorohydroquinone, 3-Chlorocatechol and 4-Chlorocatechol by Engineered Toluene o-Xylene Monooxygenases.

Toluene o-xylene monooxygenase (ToMO) was found to oxidize chlorobenzene to form 2-chlorophenol (2-CP, 4%), 3-CP (12%), and 4-CP (84%) with a total product formation rate of 1.2 ± 0.17 nmol/min/mg protein. It was also discovered that ToMO forms 4-chlorocatechol (4-CC) from 3-CP and 4-CP with initial rates of 0.54 ± 0.10 and 0.40 ± 0.04 nmol/min/mg protein, respectively, and chlorohydroquinone (CHQ, 13%), 4-chlororesorcinol (4-CR, 3%), and 3-CC (84%) from 2-CP with an initial product formation rate of 1.1 ± 0.32 nmol/min/mg protein. To increase the oxidation rate and alter the oxidation regiospecificity of chloroaromatics, as well as to study the roles of active site residues L192 and A107 of the alpha hydroxylase fragment of ToMO (TouA), we used the saturation mutagenesis approach of protein engineering. Thirteen TouA variants were isolated, among which some of the best substitutions uncovered here have never been studied before. Specifically, TouA variant L192V was identified which had 1.8-, 1.4-, 2.4-, and 4.8-fold faster hydroxylation activity toward chlorobenzene, 2-CP, 3-CP, and 4-CP, respectively, compared to the native ToMO. The L192V variant also had the regiospecificity of chlorobenzene changed from 4% to 13% 2-CP and produced the novel product 3-CC (4%) from 3-CP. Most of the isolated variants were identified to change the regiospecificity of oxidation. For example, compared to the native ToMO, variants A107T, A107N, and A107M produced 6.3-, 7.0-, and 7.3-fold more 4-CR from 2-CP, respectively, and variants A107G and A107G/L192V produced 3-CC (33 and 39%, respectively) from 3-CP whereas native ToMO did not. IMPORTANCE Chlorobenzene is a commonly used toxic solvent and listed as a priority environmental pollutant by the US Environmental Protection Agency. Here, we report that Escherichia coli TG1 cells expressing toluene o-xylene monooxygenase (ToMO) can successfully oxidize chlorobenzene to form dihydroxy chloroaromatics, which are valuable industrial compounds. ToMO performs this at room temperature in water using only molecular oxygen and a cofactor supplied by the cells. Using protein engineering techniques, we also isolated ToMO variants with enhanced oxidation activity as well as fine-tuned regiospecificities which make direct microbial oxygenations even more attractive. The significance of this work lies in the ability to degrade environmental pollutants while at the same time producing valuable chemicals using environmentally benign biological methods rather than expensive, complex chemical processes.

Retrospective analysis of open preperitoneal mesh repair of complex inguinal hernias.

PURPOSE: The open posterior approach in the form of either a Stoppa or Wantz operation may be a good alternative technique particularly in the repair of complex inguinal hernias. The term "complex inguinal hernia" designates hernias with a combination of arduous features including large hernia defects, large to giant hernia sacs, multiple recurrences, and bilaterality. In this retrospective analysis, we investigated our results of open posterior repair in view of its feasibility in patients with complex inguinoscrotal hernias. METHODS: From a series of 845 inguinal hernia patients, we retrospectively reviewed the records of 60 patients with complex inguinal hernias whom were directed to open preperitoneal repair by either a Stoppa or Wantz procedure. RESULTS: More than 80% of cases were males with large to giant inguinoscrotal hernias. One half of patients had bilateral hernias, and one fourth had recurrent hernias. Early postoperative complications occurred in almost half of patients; however, most of them were minor. The most important early complication in this series was the full recurrences we encountered in the very next morning in two patients. Eighty-three percent of patients left hospital in the first 2 days averaging 1.8 days of hospital stay. The mesh:defect area ratio is < 7 in recurrent hernias while it is > 9 in nonrecurrent cases. CONCLUSION: The open posterior approach to complex inguinal hernias facilitated both handling and repair of difficult hernias. It was very well tolerated by the patients, and yielded favorable postoperative results. We think the open posterior repair may be a method of choice in the repair of complex inguinal hernias.

Arthroscopic Assisted Percutaneous Screw Fixation of a Postage Stamp Anterior Glenoid Fracture.

Bio-absorbable anchors are widely used for Bankart repair in shoulder instability surgery. Suture anchor placement for labral repair may give rise to osteolysis and/or create stress risers in the glenoid rim, which may be the underlying reasons for glenoid rim fracture with a fracture line passing through previous anchor placement sites, the so-called "postage stamp fracture". Intraarticular fractures of the glenoid have been treated via open reduction and internal fixation through an arthrotomy, which may lead to potential postoperative complications like infection, neurovascular injuries, joint stiffness, and a long recovery period. Thus, arthroscopic techniques for the reduction and fixation of glenoid fractures have been developed. We present a case of anterior glenoid rim postage stamp fracture 9 years after glenohumeral instability surgery in a 29- year-old male. The fracture and recurrent instability were treated via arthroscopic Bankart revision repair and arthroscopic assisted percutaneous screw fixation, where the arthroscopic fracture reduction and definitive fixation were performed separately and before Bankart repair, which is different from the techniques defined in the literature previously. The patient was able to return to work at 6 weeks, to fitness training without pain or restriction at 3 months, and contact sports 6 months postoperatively. Key words: Bankart fractures, bony Bankart lesion, osseous Bankart lesion, shoulder dislocation, arthroscopy.

Cavity residue leucine 95 and channel residues glutamine 204, aspartic acid 211, and phenylalanine 269 of toluene o-xylene monooxygenase influence catalysis.

Structural analysis of toluene-o-xylene monooxygenase (ToMO) hydroxylase revealed the presence of three hydrophobic cavities, a channel, and a pore leading from the protein surface to the active site. Here, saturation mutagenesis was used to investigate the catalytic roles of alpha-subunit (TouA) second cavity residue L95 and TouA channel residues Q204, D211, and F269. By testing the substrates toluene, phenol, nitrobenzene, and/or naphthalene, these positions were found to influence the catalytic activity of ToMO. Several regiospecific variants were identified from TouA positions Q204, F269, and L95. For example, TouA variant Q204H had the regiospecificity of nitrobenzene changed significantly from 30 to 61 % p-nitrophenol. Interestingly, a combination of mutations at Q204H and A106V altered the regiospecificity of nitrobenzene back to 27 % p-nitrophenol. TouA variants F269Y, F269P, Q204E, and L95D improved the meta-hydroxylating capability of nitrobenzene by producing 87, 85, 82, and 77 % m-nitrophenol, respectively. For naphthalene oxidation, TouA variants F269V, Q204A, Q204S/S222N, and F269T had the regiospecificity changed from 16 to 9, 10, 23, and 25 % 2-naphthol, respectively. Here, two additional TouA residues, S222 and A106, were also identified that may have important roles in catalysis. Most of the isolated variants from D211 remained active, whereas having a hydrophobic residue at this position appeared to diminish the catalytic activity toward naphthalene. The mutational effects on the ToMO regiospecificity described here suggest that it is possible to further fine tune and engineer the reactivity of multicomponent diiron monooxygenases toward different substrates at positions that are relatively distant from the active site.

Neutrophil-to-lymphocyte ratio as a diagnostic biomarker for the diagnosis of acute mesenteric ischemia.

PURPOSE: Due to the diagnostic challenges and dreadful consequences of delayed treatment of acute mesenteric ischemia (AMI), a variety of diagnostic markers have been previously studied. However, the diagnostic value of neutrophil-to-lymphocyte ratio (NLR), which has been suggested to be a predictor of inflammation, has never been studied for AMI. METHODS: The data of 70 patients who underwent laparotomy (n = 8) and/or bowel resection (n = 62) for AMI (n = 70) between January 2009 and March 2014 were retrospectively analyzed. To investigate the studied parameters' role in the differential diagnosis of AMI, control groups were selected from most common reasons of inflammation-related emergent surgery, acute appendicitis (AA, n = 62) and normal appendix (NA, n = 61). White blood cell (WBC), red cell distribution width (RDW), NLR and mean platelet volume (MPV) values were recorded. Outcome variables of the study were defined as diagnostic and prognostic role of NLR in AMI. RESULTS: RDW and NLR values were found to be higher in the AMI group than the AA group (p < 0.001 and p < 0.001). Also, WBC and MPV values were higher in the AMI group than the NA group (p = 0.001 and p < 0.001). Combined sensitivity, specificity, positive predictive value and negative predictive value of RDW and NLR for recommended cut-off values were 69.4, 71.2, 57.8 and 80.4 %, respectively. CONCLUSION: High NLR value (>9.9) seems to be a valuable diagnostic marker of acute mesenteric ischemia. Combined use of NLR, RDW and other clinical assessment, could help the diagnosis of AMI, especially in the absence of advanced imaging modalities and expert radiologic interpretation.

Saturation mutagenesis of Bradyrhizobium sp. BTAi1 toluene 4-monooxygenase at alpha-subunit residues proline 101, proline 103, and histidine 214 for regiospecific oxidation of aromatics.

A novel toluene monooxygenase (TMO) six-gene cluster from Bradyrhizobium sp. BTAi1 having an overall 35, 36, and 38 % protein similarity with toluene o-xylene monooxygenase (ToMO) of Pseudomonas sp. OX1, toluene 4-monooxygenase (T4MO) of Pseudomonas mendocina KR1, and toluene-para-monooxygenase (TpMO) of Ralstonia pickettii PKO1, respectively, was cloned and expressed in Escherichia coli TG1, and its potential activity was investigated for aromatic hydroxylation and trichloroethylene (TCE) degradation. The natural substrate toluene was hydroxylated to p-cresol, indicating that the new toluene monooxygenase (T4MO·BTAi1) acts as a para hydroxylating enzyme, similar to T4MO and TpMO. Some shifts in regiospecific hydroxylations were observed compared to the other wild-type TMOs. For example, wild-type T4MO·BTAi1 formed catechol (88 %) and hydroquinone (12 %) from phenol, whereas all the other wild-type TMOs were reported to form only catechol. Furthermore, it was discovered that TG1 cells expressing wild-type T4MO·BTAi1 mineralized TCE at a rate of 0.67 ± 0.10 nmol Cl(-)/h/mg protein. Saturation and site directed mutagenesis were used to generate eight variants of T4MO·BTAi1 at alpha-subunit positions P101, P103, and H214: P101T/P103A, P101S, P101N/P103T, P101V, P103T, P101V/P103T, H214G, and H214G/D278N; by testing the substrates phenol, nitrobenzene, and naphthalene, positions P101 and P103 were found to influence the regiospecific oxidation of aromatics. For example, compared to wild type, variant P103T produced four fold more m-nitrophenol from nitrobenzene as well as produced mainly resorcinol (60 %) from phenol whereas wild-type T4MO·BTAi1 did not. Similarly, variants P101T/P103A and P101S synthesized more 2-naphthol and 2.3-fold and 1.6-fold less 1-naphthol from naphthalene, respectively.

The role of substrate binding pocket residues phenylalanine 176 and phenylalanine 196 on Pseudomonas sp. OX1 toluene o-xylene monooxygenase activity and regiospecificity.

Saturation mutagenesis was used to generate eleven substitutions of toluene-o-xylene monooxygenase (ToMO) at alpha subunit (TouA) positions F176 and F196 among which nine were novel: F176H, F176N, F176S, F176T, F196A, F196L, F196T, F196Y, F196H, F196I, and F196V. By testing the substrates phenol, toluene, and naphthalene, these positions were found to influence ToMO oxidation activity and regiospecificity. Specifically, TouA variant F176H was identified that had 4.7-, 4.3-, and 1.8-fold faster hydroxylation activity towards phenol, toluene, and naphthalene, respectively, compared to native ToMO. The F176H variant also produced the novel product hydroquinone (61%) from phenol, made twofold more 2-naphthol from naphthalene (34% vs. 16% by the wild-type ToMO), and had the regiospecificity of toluene changed from 51% to 73% p-cresol. The TouA F176N variant had the most para-hydroxylation capability, forming p-cresol (92%) from toluene and hydroquinone (82%) from phenol as the major product, whereas native ToMO formed 30% o-cresol, 19% m-cresol, and 51% of p-cresol from toluene and 100% catechol from phenol. For naphthalene oxidation, TouA variant F176S exhibited the largest shift in the product distribution by producing threefold more 2-naphthol. Among the other F196 variants, F196L produced catechol from phenol two times faster than the wild-type enzyme. The TouA F196I variant produced twofold less o-cresol and 19% more p-cresol from toluene, and the TouA F196A variant produced 62% more 2-naphthol from naphthalene compared to wild-type ToMO. Both of these positions have never been studied through the saturation mutagenesis and some of the best substitutions uncovered here have never been predicted and characterized for aromatics hydroxylation.

Cu/Zn-superoxide dismutase, paraoxonase and arylesterase activities and malondialdehyde levels in patients with familial mediterranean fever.

OBJECTIVES: In this study, alterations in antioxidant enzyme activities and malondialdehyde (MDA) levels in the serum samples of patients with familial Mediterranean fever (FMF), an autosomal recessive disease characterized by recurrent episodes of peritonitis, pleuritis, arthritis and fever, were investigated and compared with those of age- and sex-matched healthy controls. METHODS: Twenty-five patients with FMF undergoing colchicine therapy at doses of 1-1.5 mg and 25 age- and sex-matched healthy controls were included in the study. In the patients with FMF and control subjects, the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level were measured. Cu/Zn-superoxide dismutase (Cu/Zn-SOD), paraoxonase-1 (PON-1) and arylesterase (ARE) enzyme activities and MDA levels as a production of lipid peroxidation were evaluated using the appropriate methods. RESULTS: No statistically significant differences in the serum levels of ESR, CRP, Cu/Zn-SOD, MDA and PON-1 between the groups were observed (p>0.05). Serum ARE activity was significantly decreased in the patients with FMF compared with the control subjects (p<0.01). CONCLUSION: In conclusion, some abnormalities in the antioxidant defense system and lipid peroxidation may be observed in FMF patients during attack-free periods. However, further long-term studies on the subject are needed to explore altered lipid peroxidation and antioxidant defense mechanisms in patients with FMF (Tab. 1, Fig. 1, Ref. 35).

Can the patient-reported outcome instruments determine disease activity in rheumatoid arthritis?

OBJECTIVES: The aim of this study was to investigate the indicative value of the patient-reported outcome instruments (PROs) on disease activity in rheumatoid arthritis (RA). METHODS: Three hundred sixty eight patients with RA were included in this cross-sectional study. Disease activity was evaluated using both the Disease Activity Score 28 (DAS 28) and the Clinical Disease Activity Index (CDAI). Patients who had DAS 28 score < 3.60 points and CDAI score <10.00 points were allocated into the "low disease activity" group and those who had DAS 28 score > or = 3.60 points and CDAI score > or = 10.00 points into the "moderate or high disease activity" group. The Health Assessment Questionnaire (HAQ), Nottingham Health Profile (NHP), Rheumatoid Arthritis Quality of Life (RAQoL), and Short Form 36 (SF 36) were used as PROs. Logistic regression analysis was used to find variables, which had an indicative value for disease activity. RESULTS: HAQ, pain and emotional reaction subscales of NHP, and bodily pain, general health and social functioning subscales of SF 36 had independent indicative values, when DAS 28 was used as dependent variable. On the other hand, HAQ, pain and emotional reaction subscales of NHP, and general health and emotional role limitation subscales of SF 36 had indicative values when CDAI was used as dependent variable. DAS 28 and CDAI both showed HAQ as the parameter with the highest odds ratio (OR). But RAQoL had shown no independent indicative value for projecting disease activity. CONCLUSION: It was concluded that HAQ could determine disease activity in RA better than other PROs included in this study (Tab. 4, Ref. 36).

Relationship between radiographic grading of osteoarthritis and serum beta-2 microglobulin.

BACKGROUND: Beta-2 microglobulin (B2M) has been shown as a marker for monitoring inflammatory disease activity and it appears likely to have a destructive role in amyloidosis-related arthritis. Whether it has a catabolic role in osteoarthritis (OA) remains unclear. AIMS: To evaluate a possible association between serum B2M and radiographic grading of OA. METHODS: A total of 115 patients with knee OA and 30 controls were divided into subgroups according to Kellgren-Lawrence grading score and their erythrocyte sedimentation rate, C-reactive protein and serum B2M were assessed. RESULTS: B2M levels of patients were significantly higher than the controls (P < 0.01). However, there was no significant difference between OA subgroups and B2M levels had no correlation with the radiological grading. CONCLUSIONS: B2M levels were found to be higher in OA patients than controls, regardless of OA stage. These findings support the studies suggesting that B2M might be involved in the OA pathogenesis.

Correlation between soluble intercellular adhesion molecule 1 level and extracellular superoxide dismutase activity in rheumatoid arthritis: a possible association with disease activity.

OBJECTIVE: We investigated serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) and the activity of extracellular superoxide dismutase (EC-SOD) in rheumatoid arthritis (RA). We also considered whether there was a correlation between sICAM-1 and EC-SOD and disease activity. METHODS: Levels of sICAM-1 were measured in serum from 42 patients with active RA and 30 control subjects by enzyme-linked immunosorbent assay (ELISA). EC-SOD activity was determined in sera isolated from patients with active RA and from controls. RESULTS: The serum levels of sICAM-1 were significantly higher in patients with RA than in control subjects (p<0.001). In contrast, the activity of EC-SOD was significantly lower in RA patients than in healthy controls (p<0.001). A significant negative correlation was found between the levels of sICAM-1 and EC-SOD activity (r=-0.39, p<0.01). There was a statistically positive correlation between sICAM-1 levels with Ritchie articular index (RAI) score and C-reactive protein (CRP) (r=0.32, p<0.05; r=0.44, p<0.01, respectively). CONCLUSIONS: These results show that the increased levels of sICAM-1 present in active RA patients might be due to the decreased activity of EC-SOD, and increased levels of sICAM-1 may also reflect disease status or activity.

The effect of individualized diet challenges consisting of allergenic foods on TNF-alpha and IL-1beta levels in patients with rheumatoid arthritis.

OBJECTIVE: To investigate the effect of individualized diet challenges consisting of allergenic foods, defined by the skin prick test (SPT), on tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) levels in patients with rheumatoid arthritis (RA). METHODS: Twenty patients with a positive SPT response for food extracts and 20 with a negative SPT response were enrolled. None of the patients had active disease. All patients were fasted for the most common allergenic foods for 12 days and then allocated to two groups according to SPT results. Food challenges were performed with allergenic foods in the prick-positive group (PPG) and with corn and rice in the prick-negative group (PNG) for a period of 12 days. Then, allergenic foods were excluded from the PPG patients' diet and corn and rice were removed from the PNG patients' diet. Clinical examinations were performed after fasting (baseline), at the end of the challenge phase and at the end of the re-elimination phase. Stiffness, pain, tender and swollen joint counts, health assessment questionnaire (HAQ), Ritchie's articular index, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and serum TNF-alpha and IL-1beta levels were measured. RESULTS: TNF-alpha (P < 0.01), IL-1beta (P < 0.05), ESR (P < 0.05) and CRP (P = 0.001) levels and all of the clinical variables, except HAQ, were increased with food challenges in the PPG. These increases were also recorded after the re-elimination phase. In the PNG, no significant change was seen in any of the variables, except pain (P < 0.05). During the study, important differences were observed for most of the variables between the two groups. Thirteen (72%) patients in the PPG and three (18%) in the PNG experienced disease exacerbation with challenges. This aggravation continued after elimination. CONCLUSIONS: Our results suggest that individualized dietary revisions may regulate TNF-alpha and IL-1beta levels in selected patients with RA.

Inhibitor effect of omeprazole in isolated human myometrial smooth muscle.

The aim of the present study was to investigate the effect of omeprazole, an H+-K+-ATPase inhibitor, in myometrial smooth muscle strips from women undergoing elective caesarean section at term. Isolated myometrial strips taken with informed consent were obtained from eight pregnant women undergoing elective caesarean section at term (not in labour) and mounted in organ baths for recording of isometric tension. We recorded the effect of increasing concentrations of omeprazole on spontaneous and Ca2+-induced contractions of myometrial smooth muscle and on contractions of myometrial smooth muscle pretreated with indomethacin (3 x 10(-6) M) and L-NAME (3 x 10(-5) M). Omeprazole (10(-4)-10(-3) M) decreased the amplitude and frequency of spontaneous contractions in a time- and concentration-dependent manner in all myometrial smooth muscle isolated from pregnant women. The decrease in amplitude of contractions in myometrial smooth muscle reached statistical significance beginning from the concentration of 3 x 10(-4) M. Addition of indomethacin (3 x 10(-6) M) and L-NAME (3 x 10(-5) M) in to the organ baths 30 min before did not change relaxation responses to omeprazole. When 8 mM Ca2+-precontracted in Ca2+-free medium myometrial smooth muscle were exposed to increasing concentrations of omeprazole (10(-5)-10(-3) M), omeprazole produced relaxation responses in a time- and concentration-dependent manner, reaching statistical significance at 10(-4) M. These results show: (1) omeprazole time- and concentration-dependently decreased spontaneous contractile activity in myometrial smooth muscle isolated from pregnant women, (2) omeprazole-induced relaxations was not influenced by indomethacin and N(G)-nitro-L-arginine methyl ester (L-NAME), suggesting that it is not mediated by cyclooxygenase products and nitric oxide, and (3) omeprazole brought about time- and concentration-dependently relaxation of myometrial smooth muscle precontracted by 8 mM Ca2+ in Ca2+-free medium. This effect of omeprazole may be due to blockade of the calcium channels.

Effects of exogenous testosterone on isolated rabbit corpus cavernosum penis.

AIM: To study the effects of exogenous excess of testosterone on the constricting effect of phenylephrine and endothelium-dependent and -independent relaxing effects of different agonists in the corpus cavernosum penis (CCP). METHODS: Specimens of the CCP were obtained from rabbits testosterone for 1 and 2 months and untreated for 2 months after testosterone-treatment for 2 months. Preparations were mounted between two parallel platinum electrodes in organ baths. Responses to phenylephrine, carbachol, and sodium nitroprusside were obtained by adding the reagent cumulatively to the bath. RESULTS: The phenylephrine-induced contractions were decreased with no change in agonist potency (pD2 value) after both 1 and 2 month testosterone-treatment and did not return to control values in corpus cavernosum obtained from rabbits untreated for 2 months after testosterone-treatment for 2 months. Testosterone treatment for 1 or 2 months increased the endothelium-dependent relaxations induced by carbachol and decreased the relaxations elicited by electric stimulation but did not affect the relaxations induced by sodium nitroprusside. These relaxant responses to carbachol and electric stimulation did not return to control values in corpus cavernosum obtained from rabbits untreated for 2 months after testosterone-treatment for 2 months. There were no significant changes in the pD2 values calculated by agonist-induced relaxation responses in all testosterone-treatment groups compared with control group. CONCLUSION: The exogenous excess of testosterone plays an important role in erectile function by a direct action on the relaxant and contractile responses of CCP.

Treatment of closed femoral diaphyseal fractures with external fixators in children.

From August 1992 to July 1996, 57 patients with closed femoral fractures were treated by external fixator in the Orthopaedic and Traumatology Clinics, School of Medicine, Dicle University. The technique was applied to children with closed femoral fractures. Their mean age was 6 (range 4-12) years old. The mean hospitalisation period was 8 (range 5-15) days. Fixators were removed on an average of 55 (range 38-79) days. The mean follow-up period was 18 (range 9-36) months. Pintract infection was observed in 3 and refracture in 1 patient. Infection was controlled with oral antibiotics and local dressing. An external fixator was applied to a patient in whom refracture developed. No patient had malunion, nonunion, or leg length discrepancy. We propose that external fixation in closed femoral shaft fractures of children could be a rational alternative mode of therapy, since it has some advantages and can be easily removed without undergoing a second round of anaesthesia.

Effect of additional testosterone on purinergic responses in isolated rabbit corpus cavernosum strips.

Recently, it has been demonstrated that the endothelium of corpus cavernosum (CC) plays an important role on smooth muscle relaxation, which is crucial to initiate and maintain erection. We investigated the effect of long-lasting additional testosterone propionate (TP) therapy on endothelium-dependent and -independent relaxations of isolated rabbit CC. Isolated CC strips were mounted in organ baths and isometric tension was recorded. Addition of a specific inhibitor of nitric oxide synthesis, NG-nitro-L-arginin methyl ester (L-NAME), into the organ bath had no effect on the relaxation responses to adenosine (ADO), adenosine 5'-triphosphate (ATP) and sodium nitroprusside (SNP) in isolated CC strips precontracted with phenylepherine, but completely inhibited relaxation responses produced by ADP. Adenosine and adenine nucleotides relaxed the phenylepherine-induced contractile response in control strips with the potency order: ADO (62.8 +/- 3.2%) > ATP (37.1 +/- 5.2%) > ADP (25.8 +/- 2.5%). The relaxation responses to ADO, ATP and SNP in isolated rabbit CC strips were not significantly altered by additional TP therapy. The relaxation responses produced by ADP were significantly enhanced following 1 and 2 months TP therapy as compared with controls. However, in the group treated with TP for 2 months followed by a 2 months drug-free period, relaxation responses were significantly reduced compared to 1 and 2 months treatment groups, and approached control values. Increased relaxation responses to ADP following 1 and 2 months additional TP therapy may be a result of increased endothelial purinergic receptor density, or it may be due to stimulation and/or release of endothelial nitric oxide (NO) by TP.

Tolerance to isosorbide dinitrate in isolated strips of rabbit corpus cavernosum.

The aim of this study was to investigate whether prolonged exposure to a high concentration of isosorbide dinitrate (ISDN) would result in tolerance being developed against its relaxant activity in strips of corpus cavernosum, pre-contracted by phenylephrine. Under these conditions, relaxation induced by ISDN was found to be significantly reduced. Strips made tolerant to ISDN remained fully responsive to sodium nitroprusside and papaverine. Electrical field stimulation evoked relaxations which were persistent in the presence of tolerance-inducing conditions. These results indicate that desensitization of guanylate cyclase activity is not likely to be the operating mechanism for nitrate tolerance. We suggest that tolerance may result from the impairment of biotransformation of ISDN in rabbit cavernosal smooth muscle.