Use of semi-constrained total knee arthroplasty in gonarthrosis with collateral ligament insufficiency: Clinical and functional outcomes

INTRODUCTION

Achieving stability in total knee arthroplasty (TKA) is crucial for long-term implant survival. In cases of severe deformity or ligament laxity, constrained implants may be required. Traditionally, increasing constraint involved intramedullary stems. However, there are intermediary alternatives, including employing a constrained polyethylene insert without stems, thereby avoiding complications related to them. The study aims to evaluate our experience with a non-modular constrained (NMC) implant in primary TKA.

MATERIAL AND METHODS

We conducted a retrospective review of the clinical and radiographic outcomes of 108 non-stemmed primary TKAs performed at our institution between 2013 and 2021 in patients with at least 10° deformity or 10mm ligament laxity. Data included demographics, preoperative and postoperative deformities, clinical outcomes and revision rates.

RESULTS

A total of 103 patients (108 knees) with a mean age of 74 were followed up for a minimum of 2 years. The mean postoperative range of motion was 105°/0°. The median Oxford Knee Score, Knee Society Score and Knee Society Function Score were 43.5, 92 and 90, respectively. 17 knees had varus deformity (mean tibiofemoral angle of 2.7°), and 87 knees had excessive valgus deformity (mean tibiofemoral angle of 15.1°). The remaining 4 knees had a neutral alignment. The mean postoperative tibiofemoral angle was 6.8°. The overall revision rate was 6.5% (7 patients): 3 deep periprosthetic infections, 2 patellar dislocations, 1 stiffness and 1 aseptic loosening.

CONCLUSION

Our experience demonstrates favorable mid-term outcomes with the NMC implant, providing a safe alternative to stemmed implants in primary TKA, particularly in cases of severe deformity or ligament laxity.

Photoreceptor calyceal processes accompany the developing outer segment, adopting a stable length despite a dynamic core

Vertebrate photoreceptors detect light through a large cilium-based outer segment, which is filled with photopigment-laden membranous discs. Surrounding the base of the outer segment are microvilli-like calyceal processes (CPs). Although CP disruption has been associated with altered outer segment morphology and photoreceptor degeneration, the role of the CPs remains elusive. Here, we used zebrafish as a model to characterize CPs. We quantified CP parameters and report a strong disparity in outer segment coverage between photoreceptor subtypes. CP length is stable across light and dark conditions, yet heat-shock inducible expression of tagged actin revealed rapid turnover of the CP actin core. Detailed imaging of the embryonic retina uncovered substantial remodeling of the developing photoreceptor apical surface, including a transition from dynamic tangential processes to vertically oriented CPs immediately prior to outer segment formation. Remarkably, we also found a direct connection between apical extensions of the Müller glia and retinal pigment epithelium, arranged as bundles around the ultraviolet sensitive cones. In summary, our data characterize the structure, development and surrounding environment of photoreceptor microvilli in the zebrafish retina.

Photoreceptor progenitor dynamics in the zebrafish embryo retina and its modulation by primary cilia and N-cadherin

Photoreceptor cells of the vertebrate neural retina originate in the neuroepithelium, and like other neurons, must undergo cell body translocation and polarity transitions to acquire their final functional morphology, which includes features of neuronal and epithelial cells. We analyzed this process in detail in zebrafish embryos using in vivo confocal microscopy and electron microscopy. Photoreceptor progenitors were labeled by the transgenic expression of enhanced green fluorescent protein under the regulation of the photoreceptor-specific promoter crx, and structures of interest were disrupted using morpholino oligomers to knock-down specific genes. Photoreceptor progenitors detached from the basal retina at pre-mitotic stages, rapidly retracting a short basal process as the cell body translocated apically. They remained at an apical position indefinitely to form the outer nuclear layer (ONL), initially extending and retracting highly dynamic neurite-like processes, tangential to the apical surface. Many photoreceptor progenitors presented a short apical primary cilium. The number and length of these cilia was gradually reduced until nearly disappearing around 60 hpf. Their disruption by knocking-down ift88 and elipsa caused a notorious defect on basal process retraction. To assess the role of cell adhesion in the organization of photoreceptor progenitors, we knocked-down cdh2/N-cadherin and observed the cell behavior by time-lapse microscopy. The ectopic photoreceptor progenitors initially migrated in an apparent random manner, profusely extending cell processes, until they encountered other cells to establish cell rosettes in which they stayed, acquiring photoreceptor-like polarity. Altogether, our observations indicate a complex regulation of photoreceptor progenitor dynamics to form the retinal ONL, previous to the post-mitotic maturation stages.

MARCKS phosphorylation by PKC strongly impairs cell polarity in the chick neural plate

Neurulation involves a complex coordination of cellular movements that are in great part based on the modulation of the actin cytoskeleton. MARCKS, an F-actin-binding protein and the major substrate for PKC, is necessary for gastrulation and neurulation morphogenetic movements in mice, frogs, and fish. We previously showed that this protein accumulates at the apical region of the closing neural plate in chick embryos, and here further explore its role in this process and how it is regulated by PKC phosphorylation. PKC activation by PMA caused extensive neural tube closure defects in cultured chick embryos, together with MARCKS phosphorylation and redistribution to the cytoplasm. This was concomitant with an evident disruption of neural plate cell polarity and extensive apical cell extrusion. This effect was not due to actomyosin hypercontractility, but it was reproduced upon MARCKS knockdown. Interestingly, the overexpression of a nonphosphorylatable form of MARCKS was able to revert the cellular defects observed in the neural plate after PKC activation. Altogether, these results suggest that MARCKS function during neurulation would be to maintain neuroepithelial polarity through the stabilization of subapical F-actin, a function that appears to be counteracted by PKC activation.

Multi-Anti-Parasitic Activity of Arylidene Ketones and Thiazolidene Hydrazines against Trypanosoma cruzi and Leishmania spp

A series of fifty arylideneketones and thiazolidenehydrazines was evaluated against Leishmania infantum and Leishmania braziliensis. Furthermore, new simplified thiazolidenehydrazine derivatives were evaluated against Trypanosoma cruzi. The cytotoxicity of the active compounds on non-infected fibroblasts or macrophages was established in vitro to evaluate the selectivity of their anti-parasitic effects. Seven thiazolidenehydrazine derivatives and ten arylideneketones had good activity against the three parasites. The IC₅₀ values for T. cruzi and Leishmania spp. ranged from 90 nM-25 µM. Eight compounds had multi-trypanocidal activity against T. cruzi and Leishmania spp. (the etiological agents of cutaneous and visceral forms). The selectivity of these active compounds was better than the three reference drugs: benznidazole, glucantime and miltefosine. They also had low toxicity when tested in vivo on zebrafish. Trying to understand the mechanism of action of these compounds, two possible molecular targets were investigated: triosephosphate isomerase and cruzipain. We also used a molecular stripping approach to elucidate the minimal structural requirements for their anti-T. cruzi activity.

Evaluation of Phenylpropanoids in Ten Capsicum annuum L. Varieties and Their Inhibitory Effects on Listeria monocytogenes Murray, Webb and Swann Scott A

Extracts of pepper from ten different varieties of Capsicum annuumL. were prepared and their phenylpropanoids content was analysed by HPLC. There were seven different compounds identified at varying concentrations depending on pepper variety (L-phenylalanine, t-cinnamic acid, o-coumaric acid, mcoumaric acid, ferulic acid, caffeic acid and capsaicin) which are intermediates of the capsaicinoids pathway. The inhibitory action of the pepper extracts was evaluated against Listeria monocytogenes Murray, Webb and Swann Scott A by the agar diffusion test. Results showed that three of the 10 extracts had an antibacterial effect. Guajillo San Luis pepper presented the highest inhibitory effect, and contained the major concentration of cinnamic and caffeic acids. In order to analyse the individual contribution of every phenylpropanoid to the bacteriostatic effect, different concentrations were tested on the growth and survival of L. monocytogenesSwann Scott A.There were no significant differences (p> 0.05) in the t-cinnamic, o-coumaric, m-coumaric, ferulic acids and capsaicin among the samples. However, a significant difference was found between these compounds and the bactericidal action of caffeic acid. The results confirmed that L. monocytogenesSwann Scott A is inhibited by some pepper extracts, and also that some specific phenylpropanoids had a bacteriostatic effect.

Application of the DNA-specific stain methyl green in the fluorescent labeling of embryos

Methyl green has long been known as a histological stain with a specific affinity for DNA, although its fluorescent properties have remained unexplored until recently. In this article, we illustrate the method for preparing a methyl green aqueous stock solution, that when diluted can be used as a very convenient fluorescent nuclear label for fixed cells and tissues. Easy procedures to label whole zebrafish and chick embryos are detailed, and examples of images obtained shown. Methyl green is maximally excited by red light, at 633 nm, and emits with a relatively sharp spectrum that peaks at 677 nm. It is very inexpensive, non-toxic, highly stable in solution and very resistant to photobleaching when bound to DNA. Its red emission allows for unaltered high resolution scanning confocal imaging of nuclei in thick specimens. Finally, this methyl green staining protocol is compatible with other cell staining procedures, such as antibody labeling, or actin filaments labeling with fluorophore-conjugated phalloidin.

A fast, low cost, and highly efficient fluorescent DNA labeling method using methyl green

The increasing need for multiple-labeling of cells and whole organisms for fluorescence microscopy has led to the development of hundreds of fluorophores that either directly recognize target molecules or organelles, or are attached to antibodies or other molecular probes. DNA labeling is essential to study nuclear-chromosomal structure, as well as for gel staining, but also as a usual counterstain in immunofluorescence, FISH or cytometry. However, there are currently few reliable red to far-red-emitting DNA stains that can be used. We describe herein an extremely simple, inexpensive and robust method for DNA labeling of cells and electrophoretic gels using the very well-known histological stain methyl green (MG). MG used in very low concentrations at physiological pH proved to have relatively narrow excitation and emission spectra, with peaks at 633 and 677 nm, respectively, and a very high resistance to photobleaching. It can be used in combination with other common DNA stains or antibodies without any visible interference or bleed-through. In electrophoretic gels, MG also labeled DNA in a similar way to ethidium bromide, but, as expected, it did not label RNA. Moreover, we show here that MG fluorescence can be used as a stain for direct measuring of viability by both microscopy and flow cytometry, with full correlation to ethidium bromide staining. MG is thus a very convenient alternative to currently used red-emitting DNA stains.

[Extrapulmonary and extraspinal presentation of osteoarticular tuberculosis]

BACKGROUND

How to overcome the difficulty in diagnosing extrapulmonary and extraspinal osteoarticular tuberculosis? What is the most appropriate way to manage the patient?

MATERIAL AND METHODS

Retrospective series of four cases of extrapulmonary and extraspinal osteoarticular tuberculosis (two patients with knee involvement, one patient with involvement of the carpus, and a fourth patient who presented with tenosynovitis of the anterior tibial tendon of the ankle). The time elapsed from the onset of the clinical picture to the diagnosis ranged between 7 months and 2 years. The definitive diagnosis resulted from the presence of caseating granulomas in the biopsy (3 cases), and the isolation of the bacillus in culture (3 cases) or with staining (one case). Only in one case was there lung involvement after the extrapulmonary presentation. One patient had spinal involvement in the form of epidural abscess months after the extraspinal presentation. All patients received chemotherapy. Surgery was performed in 3 of the 4 cases. The Martini assessment was used to evaluate the functional outcome.

RESULTS

In all patients the lesion was cured, with two excellent and two poor functional outcomes.

CONCLUSIONS

A high clinical suspicion index is needed to prevent a delayed diagnosis. Chemotherapy is the cornerstone of treatment. Surgery is indicated mainly as a diagnostic procedure, but partial resection of the lesion may be performed at the same time.

Blast2GO goes grid: developing a grid-enabled prototype for functional genomics analysis

The vast amount in complexity of data generated in Genomic Research implies that new dedicated and powerful computational tools need to be developed to meet their analysis requirements. Blast2GO (B2G) is a bioinformatics tool for Gene Ontology-based DNA or protein sequence annotation and function-based data mining. The application has been developed with the aim of affering an easy-to-use tool for functional genomics research. Typical B2G users are middle size genomics labs carrying out sequencing, ETS and microarray projects, handling datasets up to several thousand sequences. In the current version of B2G. The power and analytical potential of both annotation and function data-mining is somehow restricted to the computational power behind each particular installation. In order to be able to offer the possibility of an enhanced computational capacity within this bioinformatics application, a Grid component is being developed. A prototype has been conceived for the particular problem of speeding up the Blast searches to obtain fast results for large datasets. Many efforts have been done in the literature concerning the speeding up of Blast searches, but few of them deal with the use of large heterogeneous production Grid Infrastructures. These are the infrastructures that could reach the largest number of resources and the best load balancing for data access. The Grid Service under development will analyse requests based on the number of sequences, splitting them accordingly to the available resources. Lower-level computation will be performed through MPIBLAST. The software architecture is based on the WSRF standard.

Vegetant bromoderma in an Infant

Bromoderma is a cutaneous reaction caused by the use of products containing bromide. In this report we describe a 2-month-old girl who was admitted to our institution with vegetative lesions on the face and scalp owing to the administration of a syrup containing sodium bromide.

Neglected traumatic posterior dislocations of the shoulder: controversies on indications for treatment and new CT scan findings

We report seven missed traumatic posterior dislocations of the shoulder in six patients. In all seven shoulders, anteroposterior radiographs did not provide the diagnosis in the emergency room after the trauma (epileptic seizure in four patients) and diagnosis was delayed for at least 24 h. The final diagnosis was reached by clinical suspicion and computed tomography (CT) scan of the seven shoulders. Two shoulders were treated by closed reduction and three were treated by closed reduction and percutaneous pinning, although four of these five shoulders presented a defect in the humeral head involving 20%-25% of the articular surface. Two shoulders dislocated for more than 6 months were treated according to Mc Laughlin's technique modified by Hawkins instead of an arthroplasty. At a minimum follow-up of 2 years and 2 months, the functional results according to Hawkins were good in all seven shoulders. There was no recurrence of the dislocation in any patient. Radiographs showed mild degenerative changes. The establishment of indications for treatment, based on the proportion of articular surface of the humeral head involved and the time of evolution of the dislocation, needs more clinical or experimental evidence. In epileptic patients, strict control of medication is of the utmost importance.

Patellar height ratios in children: an interobserver study of three methods

Several indices for patellar height measurement have been described to relate patellofemoral instability and maltracking. No known study has proved interobserver reliability of these indices when applied to growing knees. This study included comparisons of three of these indices: Caton-Deschamps, Blackburne-Peel, and Koshino. Three observers measured patellar height on 36 lateral radiographs of children's knees. The best interobserver agreement was achieved by the Caton-Deschamps method, a simple, reliable, and reproducible index that is not affected by skeletal maturation.

Radiologic study of patellar height in Osgood-Schlatter disease

There are contradictory reports regarding patellar position in the Osgood-Schlatter disease. We present a prospective statistical study of 17 patients with Osgood-Schlatter disease and 12 adolescents without anterior knee pain. The Caton-Deschamps index was assessed on strictly the lateral radiograph of the knee. The findings indicate a strong association between Osgood-Schlatter disease and patella alta. This increase in patellar height would require an increase in the force needed from the quadriceps to achieve full extension. This mechanism could be responsible for the apophyseal lesion.

Characterization of the ATPase activity of the N-terminal nucleotide binding domain of an ABC transporter involved in oleandomycin secretion by Streptomyces antibioticus

The oleB gene of Streptomyces antibioticus, oleandomycin producer, encodes an ABC transporter containing two putative ATP-binding domains and is involved in oleandomycin resistance and secretion in this organism. We have overexpressed in Escherichia coli the N-terminal nucleotide-binding domain of OleB (OleB') as a fusion protein and purified the fusion protein by affinity chromatography. The fusion protein showed ATPase activity dependent on the presence of Mg2+ ions. ATPase activity was resistant to specific inhibitors of P-, F-, and V-type ATPase whereas sodium azide and 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-C1) were strong inhibitors. The change of Lys71, located within the Walker A motif of the OleB' protein, to Gln or Glu caused a loss of ATPase activity, whereas changing to Gly did not impair the activity. The results suggest that the intrinsic ATPase activity of purified fusion protein can be clearly distinguished from other ATP-hydrolysing enzymes, including ion-translocating ATPases or ABC-traffic ATPases, both on the basis of inhibition by different agents and since it hydrolyzes ATP without interacting with a hydrophobic membrane component.

Chagas' disease in Bolivia: clinical and epidemiological features and zymodeme variability of Trypanosoma cruzi strains isolated from patients

We performed serological and pathological studies on 495 patients with Chagas' disease from different areas of Bolivia. Eighty-nine Trypanosoma cruzi strains, isolated by xenodiagnosis, were characterized by 12 isoenzyme loci and were related to the presence of cardiac changes and enteric disease with megacolon. There was a high heterogeneity of human zymodemes, presenting evidence of 2 predominant zymodemes genetically dissimilar from each other and ubiquitous in Bolivia. The frequencies of these predominant zymodemes among strains from patients were compared to strains from triatomine bugs previously studied. We observed mixtures of different zymodemes within the same patient, a phenomenon seen previously in Bolivian patients. There was no apparent difference of pathogenicity between the 2 more frequent zymodemes isolated from humans.