Ensayo quirúrgico aleatorio controlado de dos procedimientos para hallux valgus: fracaso en el reclutamiento / Surgical randomized controlled trial of two procedures for hallux valgus: recruitment failure

Antecedentes: Los ensayos quirúrgicos aleatorizados controlados (EQAC) son la mejor manera de validar los nuevos tratamientos quirúrgicos; sin embargo, comprenden una fracción muy pequeña de los artículos publicados en la literatura. Una de las razones de la falta de éxito es el hecho de no reclutar un número adecuado de pacientes. Métodos: Se presentan los resultados de 14 meses de reclutamiento de un EQAC que compara dos procedimientos quirúrgicos para el tratamiento del hallux valgus doloroso. El estudio es no ciego, de no inferioridad y paralelo con una meta de inclusión de 100 sujetos en 24 meses. Resultados: En los primeros 14 meses de reclutamiento, 94 pacientes fueron evaluados para su elegibilidad, de los cuales 54 fueron excluidos y 40 cumplían con criterios según protocolo. De estos 40, 13 fueron incluidos en el proceso de aleatorización pero sólo 11 fueron sometidos a los procedimientos quirúrgicos, ya que dos se rehusaron a dicho proceso el día de la cirugía. De los 27 pacientes elegibles restantes, en 22 no hubo más contacto después de completar la evaluación de elegibilidad y siete se negaron al procedimiento aleatorio. Los resultados indican que el estudio no recluta un número suficiente de sujetos. Conclusiones: Los datos muestran que los investigadores que planean realizar un EQAC deben ser conscientes de la gran cantidad de esfuerzo y recursos financieros necesarios para alcanzar las metas de reclutamiento de pacientes.

Background: Randomized controlled surgical trials (RCST) are the optimal way to validate new surgical treatments, yet RCSTs comprise a very small fraction of published articles in the surgical literature. One of most frequent reasons for lack of success in RCSTs is the failure to recruit an adequate number of patients. Methods: We report the results of 14 months of recruitment for an RCST comparing two different surgical procedures for the treatment of painful hallux valgus. The study is an open-label non-inferiority parallel trial, with an accrual goal of 100 subjects in 24 months. Results: In the first 14 months of recruitment, 94 patients were assessed for eligibility, of which 54 were excluded and 40 were protocol-eligible. Of these 40 only 13 enrolled in the trial. Eleven patients were randomized and treated according to the protocol, the other two withdrew prior to randomization. Of the 27 eligible patients who did not enroll and the 2 eligible patients who withdrew prior to ramdomization, 22 declined to participate in the study and 7 elected to have surgical treatment but refused randomization. Conclusions: The data show that investigators planning RCST's in surgery should be aware of the large amount of effort and significant financial resources needed to achieve patient recruitment goals.

[Surgical randomized controlled trial of two procedures for hallux valgus: recruitment failure]. / Ensayo quirúrgico aleatorio controlado de dos procedimientos para hallux valgus: fracaso en el reclutamiento.

BACKGROUND: Randomized controlled surgical trials (RCST) are the optimal way to validate new surgical treatments, yet RCSTs comprise a very small fraction of published articles in the surgical literature. One of most frequent reasons for lack of success in RCSTs is the failure to recruit an adequate number of patients. METHODS: We report the results of 14 months of recruitment for an RCST comparing two different surgical procedures for the treatment of painful hallux valgus. The study is an open-label non-inferiority parallel trial, with an accrual goal of 100 subjects in 24 months. RESULTS: In the first 14 months of recruitment, 94 patients were assessed for eligibility, of which 54 were excluded and 40 were protocol-eligible. Of these 40 only 13 enrolled in the trial. Eleven patients were randomized and treated according to the protocol, the other two withdrew prior to randomization. Of the 27 eligible patients who did not enroll and the 2 eligible patients who withdrew prior to ramdomization, 22 declined to participate in the study and 7 elected to have surgical treatment but refused randomization. CONCLUSIONS: The data show that investigators planning RCST's in surgery should be aware of the large amount of effort and significant financial resources needed to achieve patient recruitment goals.

Osteosarcoma of the pelvis.

AIMS: To describe the outcomes of a large number of patients with pelvic osteosarcoma, and to define the guidelines for appropriate treatment. METHODS: We reviewed 60 consecutive patients with primary pelvic high-grade osteosarcoma. The tumour involved the whole hemipelvis in 15 cases, while the most common location was the iliac wing in 29 cases (48.3%): 25 of these adjacent to or passing the sacroiliac joint. RESULTS: Thirty patients underwent surgery; there were 16 hindquarter amputations and 14 internal hemipelvectomies. All the patients who presented with metastasis died of their disease. In 18 cases wide margins were achieved, however, eight patients experienced local recurrence. Of the series, only eight patients are still alive. CONCLUSION: The use of intense chemotherapy and surgical wide margin, hardly seems to achieve local control, however, tumour necrosis was correlated with positive prognosis. When internal hemipelvectomy it is not safe enough, amputation must be considered, particularly for cases with sacrifice of the sciatic nerve roots or for older patients where a shorter surgical procedure can be less risky.

Perceptions and motivations of Canadian autologous blood donors.

Preoperative autologous blood donation in Canada has increased in the last decade due to concerns about allogeneic blood safety. As economic policies necessitate the validation of autologous blood donation, it is important to assess potential changes. This study examines the motivations and perceptions of patients participating in a Canadian autologous blood donation programme. The study was conducted at the Ottawa Hospital, Civic Campus. Questionnaires were developed and then administered to 100 consecutive adult autologous blood donors. The questionnaires assessed patient demographics, motivation for participation and perceptions about blood safety. Autologous donation was presented to 82% of patients as an option by their physicians. However, 59% of all patients felt that they were motivated to donate by their own fears. Patients (87%) also felt that directed blood donation should be offered due to their perception that directed donation is safer. Three-quarters of patients would be willing to pay for autologous donation. Patients are concerned about the safety of allogeneic blood and they are motivated to seek other alternatives despite the fact that allogeneic blood is very safe. These perceptions and motivations must be taken into account as health care policy changes are considered.

A refined model of the chlorosomal antennae of the green bacterium Chlorobium tepidum from proton chemical shift constraints obtained with high-field 2-D and 3-D MAS NMR dipolar correlation spectroscopy.

Heteronuclear 2-D and 3-D magic-angle spinning NMR dipolar correlation spectroscopy was applied to determine solid-state (1)H shifts for aggregated bacteriochlorophyll c (BChl c) in uniformly (13)C-enriched light harvesting chlorosomes of the green photosynthetic bacterium Chlorobium tepidum. A complete assignment of 29 different observable resonances of the 61 protons of the aggregated BChl c in the intact chlorosomes is obtained. Aggregation shifts relative to monomeric BChl c in solution are detected for protons attached to rings I, II, and III/V and to their side chains. The 2(1)-H(3), 3(2)-H(3), and 3(1)-H resonances are shifted upfield by -2.2, -1, and -3.3 ppm, respectively, relative to monomeric BChl c in solution. Although the resonances are inhomogeneously broadened and reveal considerable global structural heterogeneity, the 5-CH and the 7-Me responses are doubled, which provides evidence for the existence of at least two relatively well-defined structurally different arrangements. Ab initio quantum chemical modeling studies were performed to refine a model for the self-assembled BChl c with two different types of BChl stacks. The BChl in the stacks can adopt either anti- or syn-configuration of the coordinative bond, where anti and syn designate the relative orientation of the Mg-OH bond relative to the direction of the 17-17(1) bond. The analogy between aggregation shifts for BChl c in the chlorosome and for self-assembled chlorophyll a/H(2)O is explored, and a bilayer model for the tubular supra-structure of sheets of BChl c is proposed, from a homology modeling approach.

Total knee arthroplasty in patients who have massive osteoarticular allografts.

The authors treated 24 patients with total knee arthroplasty who had a massive allograft used to reconstruct the knee and who later had instability, degeneration, or a fracture near the articular surface of the graft develop. Patients then were followed up for a minimum of 2 years and a mean of 8.2 years. Overall, 96% of the patients retained a functional limb, although 46% underwent revision surgery, and an additional 12% had some other major complication. Statistical analysis showed a significant negative effect of chemotherapy on revision-free survival of the prosthesis. Patients with high-grade tumors were at significantly greater risk of fracture of the allograft-prosthesis composite. Certain technical factors were identified that seemed to predispose the allograft-prosthesis reconstructions to early failure. Total knee arthroplasty can be used to treat patients with complications of massive osteoarticular allografts and may prolong the functional life of an otherwise successful limb salvage reconstruction.

Photoactivation of rhodopsin: interplay between protein and chromophore.

Data in the literature suggest a finely tuned interaction between ligand (11-cis-retinal) and protein (opsin) in order to allow very efficient photoactivation of the ligand and highly vectorial rhodopsin activation with a huge increase in receptor activity. We have further investigated this interaction using ligand homologues, 13C-ligand labelling or 15N-protein labelling, in combination with Fourier transform infrared (FT-IR) and solid-state magic angle spinning (ss-MAS)-NMR spectroscopy. Using 1D rotational resonance (RR) or double-quantum heteronuclear local field (2Q-HLF) ss-MAS-NMR we report the first structure refinement of the rhodopsin chromophore in situ. These measurements yield a specification of the torsional strain in the for isomerization essential C10-C13 segment of the chromophore. This strain is thought to contribute to the high rate and stereospecificity of the photoisomerization reaction. In agreement with previous data, the C10-C13 segment region reaches a relaxed all-trans configuration at the lumirhodopsin photointermediate. MAS-NMR analysis of [15N]lysine-labelled rhodopsin reveals the presence of a 'soft' counterion, requiring intermediate water molecules for stabilization. FT-IR studies on [2H]tyrosine-labelled rhodopsin demonstrate participation of several tyrosin(at)e residues in receptor activation. One of these, probably Tyr268, is already active at the bathorhodopsin stage. Finally, the effect of ligands with single additional methyl substituents in the C10-C12 region has been investigated. They do not affect the general activation pathway, but perturb the activation kinetics of rhodopsin, suggesting steric interference with protein residues. Possible implications of these results for a structural role of water residues will be discussed, as well.

Update on acne.

Acne is a common condition seen routinely by both primary care physicians and dermatologists. Most patients have no underlying pathology and respond to traditional treatment; others, however, require more individualized evaluation and aggressive therapy. New information regarding the pathogenesis and treatment of acne is now available. This update discusses the proper evaluation of early childhood acne, the emergence of Propionibacterium acnes resistance, and the rare but serious side effects occasionally seen with minocycline. Advances in the topical treatment of acne, the use of oral contraceptives in acne, and the use and efficacy of isotretinoin are also addressed.

Endothelial damage induced by nitric oxide: synergism with reactive oxygen species.

Interactions of reactive oxygen and nitrogen species to mediate endothelial cell damage were studied in vitro. S-Nitroso-N-acetyl-DL-penicillamine (SNAP), 3-morpholinosydnonimine-N-ethylcarbamide (SIN-1) and sodiumnitroprusside (SNP) were used as NO.-donating agents. The toxicity of SIN-1 (5 mM), which produces both O2-. and NO., was reduced when catalase was added to remove H2O2 whereas superoxide dismutase had a marginal protective influence. Low doses of H2O2 producing enzymes added to low doses of SNAP (1 mM) or SNP (5 mM) substantially increased toxicity. Such damage was absent when catalase was present, but was still seen in the presence of superoxide dismutase. Non toxic doses of KCN (1 mM), antimycin A (1 microM), and rotenone (0.5 microM) in order to increase endogeneously produced reactive oxygen species increased toxic effects by 20-30% (p < 0.05). In our experiments we provide evidence that extracellularly produced H2O2 rather than O2-. enhances toxicity of NO. against endothelial cells. Likewise, endogeneous production of reactive oxygen species may increase toxicity of NO..

Patient classification systems and staffing. Part 2, Practice and process.

How can nurse executives ensure flexible staffing to meet rapidly changing patient care requirements? Part 1 of this two-part series offered a new way to conceptualize and evaluate current methods of staffing with patient classification systems (PCS). Advantages and disadvantages of each PCS-driven staffing method are explored and implications for nurse executives are examined. A promising new method of PCS-related staffing is described further in Part 2, and implementation strategies are discussed.

Patient classification systems and staffing. Part 1, Problems and promise.

How can nurse executives ensure flexible staffing to meet rapidly changing patient care requirements? Part 1 of this two-part series offers a new way to conceptualize and evaluate current methods of staffing with patient classification systems (PCS). Advantages and disadvantages of each PCS-driven staffing method are explored, and implications for nurse executives are examined. A promising new method of PCS-related staffing will be described further and implementation strategies will be discussed in Part 2.

Fine specificity of B-cell epitopes on Felis domesticus allergen I (Fel d I): effect of reduction and alkylation or deglycosylation on Fel d I structure and antibody binding.

The repertoire of B-cell epitopes on the major cat allergen, Fel d I, was analyzed with monoclonal antibodies (MoAbs) in topographic mapping studies and in immunoassays with antigen derived from other cat (Felidae) species. Four essentially nonoverlapping epitopes on Fel d I, designated Fd1A to D, were defined by use of 15 anti Fel d I MoAbs in cross-inhibition radioimmunoassay. Only MoAbs directed against epitope Fd1B bound to putative Fel d I homologues in hair and dander extracts from seven other feline species (Panthera species, [n = 5], Leptailurus serval, and Leopardus pardalus). Quantitative monosaccharide analysis showed that Fel d I was a glycoprotein, containing high levels of fucose, as well as glucosamine, galactose, and mannose. Binding of MoAbs and human IgG or IgE antibody to native, reduced and alkylated or deglycosylated Fel d I was compared by means of immunoprecipitation and immunoassay, and the effects of these treatments on the structure of Fel d I were analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis. On reduction and alkylation, Fel d I dissociated into 14 kd and 3.2 kd peptides, and deglycosylation with trifluoromethane sulfonic acid produced a 12 to 14 kd peptide. These procedures resulted in a 100- to 1000-fold loss in murine or human antibody binding activity and caused significant loss of secondary structure, as judged by circular dichroism spectroscopy. Treatment with potassium hydroxide also caused a marked loss in antigenic reactivity. In contrast, enzymatic deglycosylation generated a 9 kd peptide, which showed strong reactivity with murine and human antibodies, comparable to native Fel d I. The results show that MoAbs define a broad repertoire of B-cell epitopes on Fel d I, one of which is expressed by other cat species. These epitopes are conformational and do not appear to involve oligosaccharide residues.

Differentiation of the mammalian retinal pigment epithelium in vitro: influence of presumptive retinal neuroepithelium and head mesenchyme.

The ancestor cells of the pigment epithelium of the mammalian eye are derived from the neuroepithelial cells of the neural plate. They are neurally determined in the process of neurulation but finally decide to follow the pigment cell lineage, whereas the adjacent tissue develops into the neuroretina and the optic stalk. This decision is most probably made in the developmental stage of eye cup formation. The pigment epithelium becomes restricted to the outer leaf of the eye cup and does not encroach on the adjacent neuroepithelial tissues of the internal leaf and the eye stalk. It is therefore supposed to be channelled by a locally confined determinant factor that has not yet been identified. In the present study, development of the mammalian eye and the neural versus pigment cell decision were investigated in mouse embryos. Three approaches were used to discover the source of the putative determinant involved in the process of neuroepithelial decision. First, eye primordia were cultured from stage 11 embryos (0 somites, early neural plate stage, embryonic day 7 1/2-8) to stage 16 embryos (34 somites, neural tube stage, ed 10); this is prior to pigment cell induction. The eye primordia were first cultured in head segments and their natural position. In these experiments, 50% of the ocular neuroepithelia developed along the nerve cell and glial cell lineage. However, the other 50% of the cultured specimens partly developed into pigment epithelia. In these specimens the determinant factors had obviously remained functionally intact in vitro. In the second type of experiment, the eye primordia were also cultured within the head segments, but with the prospective neuroretina selectively removed. This experiment should show whether the inner layer of the eye cup (the prospective neuroretina) is involved in the neuroepithelial lineage decision. In these experiments 90% of the cultured eye primordia failed to develop pigmented cells. The prospective neuroretina was therefore considered as a candidate for the production of an inductive factor. Finally, eye primordia from stage 14-15 embryos (13-29 somites, ed 9-9 1/2) were either transplanted into heterotopic tissues, such as mesenchymal organs, neuroepithelium or heterochronic muscle, or grown as controls in their natural position and tissue environment. In these conditions both transplanted eye primordia and controls bore pigmented epithelium. Hence, the lineage decision, whether to form neural or pigment cell, remained undisturbed in all epitopes tested. On the basis of these experiments, it seemed unlikely that the development of pigment cells was initiated by a mesenchyme-derived factor exclusively produced near the eye vesicle.

Computer simulations of the differentiated pay structure model.

The differentiated pay structure (DPS) model determines a nurse's base pay on the basis of education, position, and expertise level, adjusting that base for part-time employment, differentials for nonbusiness hours, and single payment bonuses to reward longevity. Using computer simulations, the model was tested with data from two urban hospitals. The findings show that the model can be applied in a manner that is acceptable in terms of budget. By using the DPS model, administration can compensate for those objective employee behaviors that employers value the most.

Quantitative histologic study of the influence of anterior spinal instrumentation and biodegradable polymer on lumbar interbody fusion after corpectomy. A canine model.

Histomorphometric and microradiographic studies were performed to investigate whether there are different rates of bone remodeling based on the intrinsic stability with anterior spinal instrumentation and to evaluate if biodegradable polymer could be used clinically as the material of choice for anterior spinal instrumentation. Twenty-one coon hounds underwent anterior and posterior spinal destabilizing procedures to produce a reproducible amount of spinal instability: corpectomy of L5, discectomies and partial facetectomies of L4-5 and L5-6, resections of L5 lamina, spinous process, supra- and interspinous ligament, and ligamentum flavum. Group 1 (N = 7) underwent anterior autogenous ulna strut graft alone at L4-6; group 2 (N = 7) underwent anterior biodegradable polymer strut alone at the same level; group 3 (N = 7) underwent same bone graft as in group 1, augmented by anterior Kaneda device. Six months after surgery quantitative histologic study showed that device-related osteopenia occurred in spines treated with Kaneda device. Within the L5 vertebral body the volumetric density of bone (mm3/cm3) was less for the group with Kaneda device (group 3) compared with that without instrumentation (group 1, P less than 0.05). In the spine treated with biodegradable polymer, no adverse host tissue responses were observed histologically. In addition, osteoconductive abilities of the polymer were suggested microscopically. Its mechanical property, however, was not rigid enough to stabilize the corpectomized spine.

Effects of intracerebral administration of neuropeptide-Y on secretion of luteinizing hormone in ovariectomized sheep.

Ovariectomized ewes received unilateral infusions of 20 micrograms neuropeptide-Y (NPY) at a total of 13 intracerebral sites. Episodic secretion of luteinizing hormone (LH) was transiently suppressed on more than one occasion by daily infusions at a total of five intracerebral sites. Four of the effective sites were located within the third ventricle (two sites) and the rostral and ventral part of a lateral ventricle (two sites). The precise neural site of action of exogenous NPY cannot be determined from intraventricular administration, but it indicates a neural rather than pituitary site of NPY action to inhibit LH-releasing hormone (LHRH) in sheep. The only tissue infusion site (ventromedial nucleus) at which NPY also suppressed LH/LHRH also supports a neural action on LHRH, but this single result is insufficient to establish the neural area at which NPY acted. It is known from other work that the production of endogenous NPY in neural tissue of underfed animals is increased, and if endogenous NPY exerts effects on LH/LHRH similar to the suppression presently observed following exogenous NPY this neuropeptide might serve as one neuroendocrine factor that suppresses reproduction in underfed animals.

Anterior spinal fixation after lumbar corpectomy. A study in dogs.

An animal model was developed to simulate an unstable lumbar burst fracture that had been treated with corpectomy. A fifth lumbar laminectomy, partial facetectomy, and corpectomy was performed in twenty-one dogs. In seven dogs (the control group), a biodegradable polymer spacer was used to create a definite failure of fusion (Group I). Seven dogs were treated with a traditional anterior arthrodesis with an autogenous ulnar strut and without instrumentation (Group II). The remaining seven dogs were treated with an ulnar strut and anterior Kaneda instrumentation that was of an appropriate size for the dog (Group III). At twenty-four weeks, the results were analyzed in terms of the rate of fusion, biomechanical rigidity, neuropathological findings, and histomorphometric data on the vertebral response. The rate of fusion was significantly higher in Group III, in which the Kaneda device had been used, than it was in either Group I or Group II, in which instrumentation had not been used. Biomechanically, the spines in Group III were stiffer in torsion than those in Group I or II. There was no difference between groups in terms of the number of neuropathological changes in the spinal cord. Histomorphometric analysis showed that no meaningful device-related osteopenia occurred in the vertebrae that were spanned by the fixation device. Trabecular density was increased in the vertebrae in which the instrumentation was anchored.

Hand injury patterns in softball players using a 16 inch ball.

Softball is a popular recreational and competitive sport among both men and women. The injury rate in softball players is as high as that in baseball and basketball players. We conducted a retrospective analysis of 119 hand injuries in 108 patients treated at the University of Chicago hand clinic. All of the injuries were caused by the impact of a 16 inch circumference softball. Of the 119 injuries, 87 (73%) had bone involvement. Operative treatment was required in 26 (22%) injuries, 23 involving fractures and 3 involving soft tissue only. There was one (3.8%) operative complication. Of all injuries, 101 (86%) involved the finger joints, including 46 (39%) injuries to the distal interphalangeal (DIP) joint, 48 (40%) to the proximal interphalangeal (PIP) joint, and 7 (6%) to the metacarpophalangeal (MCP) joint. The most common DIP joint injury was a mallet injury. This fracture, the most common single type of injury in our series, accounted for 27% of all injuries. Of all mallet injuries, 86% were fractures. The most common PIP joint injury was a volar plate fracture, the second most common injury in our series. Variables such as the patient's sex, dominance or nondominance of hands, and early or late season play were not associated with a higher risk of injury. Certain parts of the hand, such as the more ulnar digits and the DIP and PIP joints, were at particularly high risk of injury.