Extra- vs. intramedullary treatment of pertrochanteric fractures: a biomechanical in vitro study comparing dynamic hip screw and intramedullary nail.

INTRODUCTION: Due to the demographic trend, pertrochanteric fractures of the femur will gain increasing importance in the future. Both extra- and intramedullary implants are used with good results in the treatment of these fractures. New, angular stable extramedullary implants promise increased postoperative stability even with unstable fractures. Additional trochanteric plates are intended to prevent secondary impaction, varisation and shortening of the fracture, as well as medialisation of the femoral shaft. The aim of this study was to perform a biomechanical comparison of both procedures regarding their postoperative stability and failure mechanisms. MATERIALS AND METHODS: Twelve fresh-frozen human femurs were randomized into two groups based on the volumetric bone mineral density (vBMD). Standardized pertrochanteric fractures (AO31-A2.3) were generated and treated either with an angular stable dynamic hip screw (DHS) or an intramedullary nail (nail). Correct implant position and the tip-apex distance (TAD) were controlled postoperatively using X-ray. Specimens were mounted in a servohydraulic testing machine and an axial loading was applied according to a single-leg stance model. Both groups were biomechanically compared with regard to native and postoperative stiffness, survival during cyclic testing, load to failure, and failure mechanisms. RESULTS: TAD, vBMD, and native stiffness were similar for both groups. The stiffness decreased significantly from native to postoperative state in all specimens (p < 0.001). The postoperative stiffness of both groups varied non-significantly (p = 0.275). The failure loads for specimens treated with the nail were significantly higher than for those treated with the DHS (8480.8 ± 1238.9 N vs. 2778.2 ± 196.8 N; p = 0.008). CONCLUSIONS: Extra- and intramedullary osteosynthesis showed comparable results as regards postoperative stiffness and survival during cyclic testing. Since the failure load of the nail was significantly higher in the tested AO31-A2.3 fracture model, we conclude that intramedullary implants should be preferred in these, unstable, fractures.

Spinal Hypertrophic Pachymeningitis in Antineutrophilic Cytoplasmic Antibody-Negative Vasculitis: A Case Report.

Hypertrophic pachymeningitis (HPM) is a rare but extremely debilitating disease. It is even rarer for HPM to be seen in association with antineutrophil cytoplasmic antibody (ANCA)-negative vasculitis. In this case, we are presenting HPM that was diagnosed in a 28-year-old female patient who presented with worsening back pain. Imaging revealed dural-based enhancing masses affecting the thoracic spinal cord with compression. Infectious etiologies were ruled out and a total of three biopsies failed to show any evidence of granulomatous inflammation, malignancy, or evidence of immunoglobulin G4-related disease. ANCA was negative on repeated testing. The patient was managed with repeated short courses of steroids that resulted in symptomatic control as well as radiological stability of the disease. This is an extremely rare case of atypical presentation of spinal HPM that is likely associated with granulomatous and polyangiitis without other manifestations of the disease except for nasal septal perforation. This case is a supplement to a limited body of knowledge and established cases of HPM in ANCA-negative, ANCA-associated vasculitis.

Assessment of factors influencing retention in the Philippine National Rural Physician Deployment Program.

BACKGROUND: The 'Doctors to the Barrios' (DTTB) Program was launched in 1993 in response to the shortage of doctors in remote communities in the Philippines. While the Program has attracted physicians to work in such areas for the prescribed 2-year period, ongoing monitoring shows that very few chose to remain there for longer and be absorbed by their Local Government Unit (LGU). This assessment was carried out to explore the reasons for the low retention rates and to propose possible strategies to reverse the trend. METHODS: A mixed methods approach was used comprising a self-administered questionnaire for members of the current cohort of DTTBs, and oral interviews with former DTTBs. RESULTS: Among former DTTBs, the wish to serve rural populations was the most widely cited motivation. By comparison, among the current cohort of DTTBs, more than half joined the Program due to return of service obligations; a quarter to help rural populations, and some out of an interest in public health. Those who joined the Program to return service experienced significantly less satisfaction, whilst those who joined out of an interest in public health were significantly more satisfied with their rural work. Those who graduated from medical schools in the National Capital Region were significantly more critical about their compensation and perceived there to be fewer options for leisure in rural areas. With regard to the factors impeding retention, lack of support from the LGU was most frequently mentioned, followed by concerns about changes in compensation upon absorption by the LGU, family issues and career advancement. CONCLUSIONS: Through improved collaboration with the Department of Health, LGUs need to strengthen the support provided to DTTBs. Priority could be given to those acting out of a desire to help rural populations or having an interest in public health, and those who have trained outside of the National Capital Region. Whether physicians should be able to use the Program to fulfil return service obligations should be critically assessed.

Immune responses in mice after immunization with antigens from different stages of the parasite Schistosoma mansoni.

Mice responses to immunization with Schistosoma mansoni antigens were investigated. Priming with cercarial antigen preparation (CAP) induced significant (P < 0.05) IgM, IgG, IgG2a, IgG2b, and IgA increases, while booster caused a significant IgG1 increase. A soluble worm antigen preparation (SWAP) caused significant IgG elevation. Priming with soluble egg antigen (SEA) caused significant IgM and IgG2a increases, while booster induced significant IgM, IgG and IgA increases. CAP-immunized mice sera (IMS) recognized CAP peptides ranging from 23-78 kDa. SWAP-IMS recognized SWAP peptides ranging from 40-75 kDa. SEA-IMS recognized SEA peptides ranging from 33-101 kDa. The cross-reactive peptides among the 3 antigens were identified. CAP caused significant increases in mesenteric lymph nodes (MLNs) CD(4,8)+, B lymphocytes, CD8+ thymocytes, CD4+ T and B splenocytes. SWAP priming caused significant increases in MLNs CD(4,8)+ thymocytes and B splenocytes. SWAP booster caused significant increases in MLNs CD8+ T and B lymphocytes, CD(4,8)+ thymocytes and CD4+ T and B splenocytes. SEA caused significant increase in CD4+ T cells.

A cyclohexanecarboxamide derivative with inhibitory effects on Schistosoma mansoni cercarial serine protease and penetration of mice skin by the parasite.

A cyclohexanecarboxamide derivative, N-phenyl-N-[1-(piperidine-1-carbonyl)cyclohexyl] benzamide (MNRC-5), was evaluated for its inhibitory effects on Schistosoma mansoni cercarial serine protease activity and cercarial penetration. MNRC-5 exerted an inhibitory effect on S. mansoni cercarial serine protease at serial concentrations of the specific chromogenic substrate Boc-Val-Leu-Gly-Arg-PNA for such enzyme family and the inhibitory coefficient (Ki) value was deduced. Moreover, topical treatment of mice tails with the most potent inhibitory concentration of MNRC-5 formulated in jojoba oil successfully blocked cercarial penetration as demonstrated by a significant reduction (75%; p < 0.05) in the recovered S. mansoni worms from treated mice in comparison to control ones whose tails were painted with jojoba oil base containing no MNRC-5. In addition, the IgM and IgG reactivities to crude S. mansoni cercarial, worm and egg antigens were generally lower in sera from treated infected mice than untreated infected mice. In conclusion, we report on a new serine protease inhibitor capable for blocking penetration of host skin by S. mansoni cercariae as measured by lowering worm burden and decrease in the levels of both IgM and IgG towards different bilharzial antigens upon topical treatment.

Biochemical properties of an intracellular serpin from Echinococcus multilocularis.

A serpin of the intracellular type from the tapeworm Echinococcus multilocularis was expressed in Escherichia coli, purified by ion exchange chromatography and tested for inhibitory activity against several proteinases. The recombinant protein, which after transcriptional induction, represents about 20 % of total cellular protein, is biochemically active and inhibits trypsin and the trypsin-like plasmin as well as pig pancreatic and human neutrophil elastase. Implications regarding its biochemistry and biological function are discussed.

Is the calorie concept a real solution to the obesity epidemic?

BACKGROUND: The obesity epidemic has been growing steadily across the whole world, and so far not a single country has been able to reverse it. The cause of obesity is stated by the World Health Organization as an energy imbalance between calories consumed and calories expended. However, growing evidence suggests that the calorie imbalance concept may not be sufficient to manage and reverse the obesity epidemic. OBJECTIVE: To discuss the use of the calorie imbalance concept and its elements as a tool for weight management as well as its possible negative consequences and implications for public health, with the aim to point toward the need of an updated concept for causes of obesity. This update should guide public health interventions more efficiently to limit obesity by preventing weight gain or promoting weight loss. METHODS: This is a literature reviews based on a semi-structured approach to determine the material to be examined. RESULTS: After revisiting general facts about fat generation and accumulation, we propose an updated concept for the causes of obesity including diet composition and hormonal regulation of fat metabolism. CONCLUSIONS: We discuss how this updated concept could benefit the overall efficiency of strategies against obesity, and hypothesize how potential resistance to adopting this new view could be lowered.

Comparison of the role of dendritic cells and macrophages in inducing protective immunity against Schistosoma japonicum.

OBJECTIVE: To compare a potential role of dendritic cells (DCs) and macrophages in inducing protective immunity against infection with Schistosoma japonicum. METHODS: DCs and macrophages were pulsed in vitro with soluble egg antigen (SEA) of S. japonicum. BALB/c mice were injected three times with DCs or macrophages, either antigen-pulsed or not, and challenged with 40 +/- 2 cercariae of S. japonicum per mouse. Worms were collected 42 days later by portal perfusion of the mice and egg number of liver was calculated. To evaluate whether protective immunity had been induced by preparations of DCs or macrophages, the worm burden and fertility (eggs per female per mouse liver) were compared between the groups of mice. The antibody level against SEA was detected by ELISA. RESULTS: With respect to mice injected with untreated cells, numbers of worms and eggs per female worms were significantly reduced in the groups of mice having received pulsed DCs (26. 3% and 37.9%, respectively), or pulsed macrophages (22.0% and 30.7%). Untreated DCs and macrophages induced no significant effects. The antibody level against SEA rose in sera of all groups of mice up to 42 days after the challenge, but most pronounced in those immunized with pulsed DCs, although this was not significantly different from other groups. CONCLUSION: The results suggest that the protective immunity against S. japonicum might be induced by DCs to a higher extent than by macrophages after in vitro pulsing with egg antigen.

Serodiagnosis of Schistosoma mansoni infections in an endemic area of Burkina Faso: performance of several immunological tests with different parasite antigens.

The performance of indirect haemagglutination assays (IHA), enzyme-linked immunosorbent assays (ELISA) and indirect immunofluorescent antibody tests (IFAT) were compared with 450 sera from a Schistosoma mansoni-endemic area in Burkina Faso. All participants in this survey provided at least one sample each of stool, urine and serum. From those with an egg-negative Kato-Katz thick smear, a second stool sample was examined. IHA was based on either extracts of adult S. mansoni worms (SmIHA) or S. japonicum egg antigen (SjIHA). For ELISA, three antigen preparations were used, namely: (i) soluble S. mansoni adult worm antigens (SWAP); (ii) soluble S. mansoni egg antigens (SEA); and (iii) a cationic exchange fraction of S. mansoni eggs (CEF6). IFAT was performed with S. mansoni male worm sections. Among the egg-excretors, the sensitivity of ELISA was high and egg antigens performed slightly better (SEA, 96%; CEF6, 97%) than worm antigen (94%). Sensitivity of IHA was satisfactory with homologous (Sm, >85%), but not heterologous (Sj, 56%) parasite antigen. In IFAT, the parenchyma-associated fluorescence showed high sensitivity (95%), but gut-associated fluorescence, which is known to be a sensitive diagnostic marker for schistosome-infected European travelers, was observed only in 76% of a sub-sample of 100 of the endemic sera. Among sera from egg-negative individuals, many gave positive reactions in several or all of the tests employed. These reactions (formally "false positive") are considered to represent true infections, since chemotherapy had not yet been delivered to this population. For the purpose of further surveys in Burkina Faso or other resource-poor settings, we suggest IHA as an accurate diagnostic test and propose to further improve its performance by including egg rather than worm antigens.

Synthesis of new 4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine derivatives with an incorporated thiazolidinone moiety and testing their possible serine protease and cercarial elastase inhibitory effects with a possible prospective to block penetration of Schistosoma mansoni cercariae into the mice skin.

5-Substituted 4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine were synthesized by interaction of 4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-sulfonylhydrazide with some aldehydes to give the corresponding Schiff-bases, which after cyclization gave corresponding thiazolidinones. For some of the thiazolidinones, Mannich bases reaction was carried out. All the derivatives were tested for their possible inhibitory effect on Schistosoma mansoni cercarial elastase (CE). Only, N-(4-methylbenzyledine)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-sulfonylhydrazide was found to have potent inhibitory effect on the CE activity with IC50 = 264 microM. Upon its use as a paint for mice tails before infection with S. mansoni cercariae, the compound formulated in jojoba oil caused a significant reduction (93%; P-value = 0.0002) in the worm burden. IgG & IgM in mice sera were measured by using several S. mansoni antigens by ELISA. Sera from treated infected mice (TIM) 2, 4, and 6 weeks (W) post infection (PI) showed 1.2 folds lower, 1.2 folds higher, 1.7 folds lower IgM reactivity against soluble cercarial antigenic preparation (CAP), respectively, when compared with sera collected from infected untreated mice (IUM). Sera from TIM 2, 4, and 6WPI showed 1.3, 1.6, and 1.7 folds higher IgG reactivity, respectively against CAP than the IgG reactivity from IUM. Sera from TIM 2, 4 and 6WPI showed 1.5, 1.2 folds lower and 1.4 folds higher IgM reactivity, respectively against soluble worm antigenic preparation (SWAP) when compared with sera collected from IUM. Sera from TIM 2, 4, and 6WPI showed 1.4, 1 folds lower and 1 fold higher IgG reactivity, respectivley to SWAP when compared with sera from IUM. Sera from TIM 2, 4, and 6WPI had generaly lower IgM and IgG reactivities against soluble egg antigen (SEA) when compared with sera from IUM.

Invasion by schistosome cercariae: neglected aspects in Schistosoma japonicum.

Skin invasion by schistosome cercariae was recently discussed in Trends in Parasitology. However, only Schistosoma mansoni was considered, possibly because this species predominates in laboratory studies (at least outside China). One may be tempted to extrapolate from the "model" S. mansoni to other schistosomes, but Schistosoma japonicum must not be neglected. This schistosome is distinguishable from others (particularly S. mansoni) by virtue of its remarkable speed and success of migration, as well as by specific biochemical and immunological features. This leads to the hypothesis that S. japonicum is atypical with respect to the enzymes that facilitate skin penetration.

SmCB2, a novel tegumental cathepsin B from adult Schistosoma mansoni.

Papain-like cysteine endopeptidases have been recognized as potential targets for chemotherapy and serodiagnostic reagents in infections with the human parasitic helminth Schistosoma. A novel cathepsin B endopeptidase from adult S. mansoni has been isolated and characterized. The enzyme is termed SmCB2 to distinguish it from the first recorded schistosome cathepsin B, SmCB1, also known as Sm31. A rapid and convenient protocol involving anion exchange and affinity chromatography is described for the isolation of SmCB1 and SmCB2 from the same parasite starting material. SmCB2 has been functionally expressed in and purified from Pichia pastoris. Both native and recombinant SmCB2 migrate similarly (33 kDa) by SDS-PAGE. Both display strict acidic pH activity profiles and similar K(m) and k(cat) for dipeptidyl amidomethylcoumarin substrates. We conclude that the recombinant enzyme is properly folded. The S(2) subsite specificity of recombinant SmCB2 exhibits the preferences Phe>Leu>Val>>Arg. By immunoblotting with anti-SmCB2 IgG, a 33 kDa protein was identified in soluble extracts of male schistosomes. By immunohistochemistry, SmCB2 was localized in the tegumental tubercles and parenchyma of males with less product being visualized in the parenchyma of females. The enzyme may be lysosomal and function at the host parasite-interface.

Emergence of infections with Schistosoma mansoni in the Dhofar Governorate, Oman.

Infections with Schistosoma mansoni were identified in an area of Dhofar (Oman), where this parasite had been virtually absent during recent years and was reported only very sporadically before 1992. In the present survey, performed late in 2001, between 1 and 13% of children (n=519) were found to excrete eggs (one Kato-Katz-smear) in four schools, from four different villages, but no infections were detected in additional five schools (n=281). Infections were light (<72 eggs/g of faeces) in 19 of the 36 children found infected. Serologic examination of sera (n=511) was done by ELISA (based on soluble worm antigen) and immunofluorescence tests (IFT, based on cryostat sections of adult S. mansoni). The prevalence according to serological tests was between 3 and 43% in the four schools with infected children. Positive test results were taken to reflect active infections, since false positive reactions could largely be excluded. According to ultrasound (US) examinations performed on 96 individuals (children and adults) from the four villages, livers were normal in all except three cases of mild pathology, which could be assigned to schistosomiasis mansoni (pattern C, ages 32-40 years). All data suggest that transmission of S. mansoni has been re-introduced only recently in Dhofar and that this emergence of schistosomiasis is limited to at most a few foci.

Schistosoma mansoni and Schistosoma haematobium: identification and characterization of glycoconjugate antigens in the hemolymph of infected vector snails.

Two carbohydrate epitopes were identified by monoclonal antibodies (KCS and E2) and characterized with respect to their immunoreactivity, monosaccharide structure, and location. Immunofluorescence demonstrated the presence of both epitopes on the surfaces of sporocysts, cercariae, and miracidia of Schistosoma mansoni, Schistosoma haematobium, and Schistosoma japonicum. However, spatial distribution and density of expression varied among species and developmental stages, and neither epitope was detectable on adult worm surfaces. Both glycans were found in the hemolymph of infected, but not uninfected, intermediate snail hosts. The presence of epitopes in hemolymph, as well as in schistosome eggs, is species-specific for KCS, recognizing only S. mansoni, and partly specific for E2, which reacted predominantly with S. haematobium. Immunoaffinity purification of target antigens for KCS and E2 from hemolymph of infected Biomphalaria and Bulinus, respectively, followed by carbohydrate composition analysis revealed a high content of fucose in both glycans. Methylation analysis demonstrated exclusively terminal fucose for the target antigen of KCS and terminal as well as internal fucose for the one of E2. Removal of terminal fucose abolished reactivity with both monoclonal antibodies. Both glycans are different from previously characterized schistosome carbohydrates. Their biological function(s) remain to be defined.

[Experimental study on hybridoma cells agglutination test for diagnosis of schistosomiasis japonica in mice].

OBJECTIVE: To detect the infection of Schistosoma japonicum in mice with a novel test based on agglutination of hybridoma cells and to study the mechanism of the hybridoma cells agglutination. METHODS: The procedure was developed with a murine cell line H226 producing a monoclonal antibody specific to schistosome 31/32 kDa antigen and sera collected from mice infected with different numbers (10, 30, 50) of S. japonicum cercariae in different period. Immunofluorescent test was carried out with the hybridoma cells and schistosome-infected sera. RESULTS: The circulating antigen was detected by the test as early as 2 weeks after a heavy infection and all mice showed positive results in the test by 5 weeks after infection. The titers of antigen rose along with the time post infection, and the titers of sera from heavy infection were statistically higher than that from the mice receiving a lower number of cercariae. Specific yellowish green fluorescence appeared on the membrane of the hybridoma cells; no signal was detected inside. CONCLUSION: Hybridoma cell agglutination test (HCAT) may become useful to diagnose schistosomiasis.

[Expression of inducible nitric oxide synthase in the livers of mice infected with Schistosoma japonicum].

OBJECTIVE: To study the expression of inducible nitric oxide synthase (iNOS) in livers of mice infected with Schistosoma japonicum. METHODS: The livers of NMRI mice infected with S. japonicum were collected on day 21, 28, 38, 45 post infection (p.i.), total RNA of livers were extracted and kinetics of the mRNA expression of iNOS were detected by RT-PCR, the protein expression of iNOS was then confirmed by Western blotting and the distribution of iNOS in the infected liver was determined by immunohistochemical methods. RESULTS: The mRNA expression of iNOS was not detectable in the uninfected liver, iNOS mRNA expression was detected on day 21 p.i., the expression increased on day 28 p.i. and peaked on day 38 p.i., then decreased slightly on day 45 p.i. Western blotting showed an iNOS expression in the livers only on day 38, 45 p.i. IFA test showed that the expression of iNOS was mainly distributed in the granuloma of the livers. CONCLUSION: S. japonicum infection can induce the expression of iNOS in a time-dependent manner in the liver of the host, and eggs may be the main factor in inducing the expression.

The effects of T cell deficiency on the development of worms and granuloma formation in mice infected with Schistosoma japonicum.

It is widely accepted that the immune response of the host attacks the parasite and the parasite appears to develop strategies to evade the assault. However, there is increasing evidence that the development of a parasite may be also positively influenced by the immune response of host. In this paper, we explore the effects of T cell deficiency on the development of the worms and granuloma formation in mice infected with cercariae of Schistosoma japonicum. T cell-deficient (nude) mice supported normal parasite survival and fecundity, but compared to normal mice delayed the worms' development (length and female fecundity) until 28 days after infection. However, these differences equaled out at 35 and 42 days. The nude mice apparently suppressed the size of granuloma in the livers around the eggs of S. japonicum. The granulomas were composed predominantly of neutrophils but with significantly fewer eosinophils in nude compared to normal mice. In addition, hepatocyte necrosis occurred in the vicinity of granulomas in nude but not normal mice. This is consistent with egg-granuloma formation in the host being dependent on T-lymphocyte functions and shows that the effect of T cell deficiency on the development of the worms is transitory in S. japonicum.

Schistosoma japonicum and S. mansoni cercariae: different effects of protein in medium, of mechanical stress, and of an intact complement system on in vitro transformation to schistosomula.

The cercariae of Schistosoma japonicum were subjected in vitro to treatments known for Schistosoma mansoni to generate schistosomula-like organisms. As a technical prerequisite to pipette or to otherwise handle the sticky cercariae of S. japonicum, the addition of protein to water or medium was found to abolish the stickiness of cercariae of this species. Shearing forces exerted in vitro by syringe (22 G) passage are known since long to fully transform S. mansoni cercariae, but this treatment was found to be much less efficient with S. japonicum. Thus, even with very narrow needles (27 G), complete transformation of cercariae was not obtained with S. japonicum. Complement, provided by fresh human serum, is also well known to induce rapid transformation of S. mansoni cercariae with subsequent killing of the schistosomula. This treatment of S. japonicum cercariae induced degeneration of the tails and strongly promoted the transformation to schistosomula-like organisms, but at a much slower pace. These effects were absent from sera either heat-inactivated or depleted of factor B or of complement component C8, but were restored after adding the purified respective complement components. The schistosomula-like organisms of S. japonicum were not susceptible to lysis after 1 day of in vitro culture in the presence of 50% fresh human serum, although both cercariae and schistosomula of S. mansoni were killed under these conditions. In conclusion, the dynamics of in vitro transformation of S. japonicum cercariae differ significantly from those of S. mansoni, and complement has a major transformation-promoting activity.