Patient-related outcomes of patellofemoral arthroplasty: experience of a single center.

PURPOSE: The purpose of this prospective study was to present the experience of a single center on patellofemoral arthroplasty, in terms of patient-related outcomes. METHOD: From January 2005 to January 2016, 42 patients with isolated patellofemoral osteoarthritis were treated. The patients were assessed using the Oxford Knee Score preoperatively, and one, five, and eight year(s) after surgery. The data of the patients were analyzed using linear mixed effects models. A P value of 0.05 was considered statistically significant. RESULTS: Among 42 patients who underwent patellofemoral arthroplasty, only 25 patients (31 limbs involved) had records up to 5 years. There was a significant clinical improvement of Oxford Knee Score postoperatively (P < 0.05), lowering the score on average by 10.4 ± 1.5 one year after surgery and 8.9 ± 1.9 five years after surgery. This improvement was independent of the types of implants (P > 0.05), gender (P > 0.05), age (P < 0.05), and body mass index (BMI) (P < 0.05). CONCLUSION: Patellofemoral arthroplasty can significantly improve the knee function, and this improvement is independent of the type of implant, gender, age, and BMI. However, further studies will need to assess the long-term outcomes of PFA.

Use of linezolid in neonatal and pediatric inpatient facilities--results of a retrospective multicenter survey.

The purpose of this investigation was to describe the use of linezolid in pediatric inpatient facilities. A retrospective multicenter survey including data from nine participating tertiary care pediatric inpatient facilities in Germany and Austria was undertaken. Data on 126 off-label linezolid treatment courses administered to 108 patients were documented. The survey comprises linezolid treatment in a broad spectrum of clinical indications to children of all age groups; the median age was 6.8 years (interquartile range 0.6-15.5 years; range 0.1-21.2 years; ten patients were older than 18 years of age but were treated in pediatric inpatient units). Of the 126 treatment courses, 27 (21%) were administered to preterm infants, 64 (51%) to pediatric oncology patients, and 5% to patients soon after liver transplantation. In 25%, the infection was related to a medical device. Linezolid iv treatment was started after intensive pre-treatment (up to 11 other antibiotics for a median duration of 14 days) and changed to enteral administration in only 4% of all iv courses. In 39 (53%) of 74 courses administered to children older than 1 week and younger than 12 years of age, the dose was not adjusted to age-related pharmacokinetic parameters. In only 17 courses (13%) was a pediatric infectious disease consultant involved in the clinical decision algorithm. Linezolid seemed to have contributed to a favorable outcome in 70% of all treatment courses in this survey. Although retrospective, this survey generates interesting data on the off-label use of linezolid and highlights several important clinical aspects in which the use of this rescue antibiotic in children might be improved.

Successful treatment of anti-N-methyl-D-aspartate receptor encephalitis presenting with catatonia.

The case of a 12-year-old girl with the typical clinical symptoms of the recently described anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is reported. Within 6 weeks the full clinical spectrum of this condition presented with seizures, agitation, stupor, autonomic instability, dysphagia and hypoventilation leading to a diagnosis of pernicious catatonia. MRI and CSF glucose, protein and lactate were repeatedly normal. EEG revealed rhythmical slowing. No teratoma was detected. Recognition of the unique pattern of the clinical symptoms led to early consideration of this disease which was confirmed by detection of anti-NMDAR antibodies. After high dose prednisolone without clinical improvement, plasmapheresis was followed by a rapid reduction in antibodies and recovery within a few weeks. To our knowledge this is the youngest patient with anti-NMDAR encephalitis to have been described to date. We speculate that NMDAR antibodies may be directly involved in the pathogenesis of this disease.

A combined patch-clamp and electrorotation study of the voltage- and frequency-dependent membrane capacitance caused by structurally dissimilar lipophilic anions.

Interactions of structurally dissimilar anionic compounds with the plasma membrane of HEK293 cells were analyzed by patch clamp and electrorotation. The combined approach provides complementary information on the lipophilicity, preferential affinity of the anions to the inner/outer membrane leaflet, adsorption depth and transmembrane mobility. The anionic species studied here included the well-known lipophilic anions dipicrylamine (DPA(-)), tetraphenylborate (TPB(-)) and [W(2)(CO)(10)(S(2)CH)](-), the putative lipophilic anion B(CF(3))(4)(-) and three new heterocyclic W(CO)(5) derivatives. All tested anions partitioned strongly into the cell membrane, as indicated by the capacitance increase in patch-clamped cells. The capacitance increment exhibited a bell-shaped dependence on membrane voltage. The midpoint potentials of the maximum capacitance increment were negative, indicating the exclusion of lipophilic anions from the outer membrane leaflet. The adsorption depth of the large organic anions DPA(-), TPB(-) and B(CF(3))(4)(-) increased and that of W(CO)(5) derivatives decreased with increasing concentration of mobile charges. In agreement with the patch-clamp data, electrorotation of cells treated with DPA(-) and W(CO)(5) derivatives revealed a large dispersion of membrane capacitance in the kilohertz to megahertz range due to the translocation of mobile charges. In contrast, in the presence of TPB(-) and B(CF(3))(4)(-) no mobile charges could be detected by electrorotation, despite their strong membrane adsorption. Our data suggest that the presence of oxygen atoms in the outer molecular shell is an important factor for the fast translocation ability of lipophilic anions.

Surviving high-intensity field pulses: strategies for improving robustness and performance of electrotransfection and electrofusion.

Electrotransfection and electrofusion, both widely used in research and medical applications, still have to face a range of problems, including the existence of electroporation-resistant cell types, cell mortality and also great batch-to-batch variations of the transfection and fusion yields. In the present study, a systematic analysis of the parameters critical for the efficiency and robustness of electromanipulation protocols was performed on five mammalian cell types. Factors examined included the sugar composition of hypotonic pulse media (trehalose, sorbitol or inositol), the kinetics of cell volume changes prior to electropulsing, as well as the growth medium additives used for post-pulse cell cultivation. Whereas the disaccharide trehalose generally allowed regulatory volume decrease (RVD), the monomeric sugar alcohols sorbitol and inositol inhibited RVD or even induced secondary swelling. The different volume responses could be explained by the sugar selectivity of volume-sensitive channels (VSC) in the plasma membrane of all tested cell types. Based on the volumetric data, highest transfection and fusion yields were mostly achieved when the target cells were exposed to hypotonicity for about 2 min prior to electropulsing. Longer hypotonic treatment (10-20 min) decreased the yields of viable transfected and hybrid cells due to (1) the cell size reduction upon RVD (trehalose) or (2) the excessive losses of cytosolic electrolytes through VSC (inositol/sorbitol). Doping the plasma membrane with lipophilic anions prevented both cell shrinkage and ion losses (probably due to VSC inhibition), which in turn resulted in increased transfection and fusion efficiencies.

Atypical hamstrings electromyographic activity as a compensatory mechanism in anterior cruciate ligament deficiency.

Anterior cruciate ligament (ACL) deficiency may cause functional instability of the knee (noncopers), while other patients compensate and perform at the same level as before injury (copers). This pilot study investigated whether there is a compensatory electromyographic (EMG) activity of the hamstrings in copers, noncopers and control patients. Ten patients with an ACL deficiency were equally divided into two groups of copers and noncopers. All patients underwent gait analysis with EMG of six muscles around the knee. Ten healthy young men formed the control group. In contrast to noncopers, copers showed an atypical semitendinosus activity during stance phase; the corresponding trend was found in biceps femoris activity. There was no difference between copers and controls in knee extension during stance phase. The noncopers had less knee extension. Atypical hamstring muscle activity may thus be a compensatory mechanism by which copers enable themselves to perform on a normal level.

Phloretin-induced changes of lipophilic ion transport across the plasma membrane of mammalian cells.

The adsorption of the hydrophobic anion [W(CO)(5)CN](-) to human lymphoid Jurkat cells gave rise to an additional anti-field peak in the rotational spectra of single cells, indicating that the cell membrane displayed a strong dielectric dispersion in the kilohertz to megahertz frequency range. The surface concentration of the adsorbed anion and its translocation rate constant between the two membrane boundaries could be evaluated from the rotation spectra of cells by applying the previously proposed mobile charge model. Similar single-cell electrorotation experiments were performed to examine the effect of phloretin, a dipolar molecule known to influence the dipole potential of membranes, on the transport of [W(CO)(5)CN](-) across the plasma membrane of mammalian cells. The adsorption of [W(CO)(5)CN](-) was significantly reduced by phloretin, which is in reasonable agreement with the known phloretin-induced effects on artificial and biological membranes. The IC(50) for the effect of phloretin on the transport parameters of the lipophilic ion was approximately 10 microM. The results of this study are consistent with the assumption that the binding of phloretin reduces the intrinsic dipole potential of the plasma membrane. The experimental approach developed here allows the quantification of intrinsic dipole potential changes within the plasma membrane of living cells.

Staphylococcus aureus biofilm formation on different gentamicin-loaded polymethylmethacrylate bone cements.

In this in vitro study, the formation of a Staphylococcus aureus biofilm on six gentamicin-loaded bone cements (CMW1, CMW3, CMW Endurance, CMW2000, Palacos, and Palamed) was determined in a modified Robbins device over a 3 days time span and related with previously (Van de Belt et al., Biomaterials 21 (2000) 1981) measured kinetics of antibiotic release by these cement brands. The influence of gentamicin release on biofilm formation was quantified by expressing the number of colony-forming units on gentamicin-loaded cement relative to the number of viable organisms on unloaded cement of the same brand. Biofilms formed on all gentamicin-loaded cements, despite the release of antibiotics, followed a consistent pattern in time with a maximum number of colony-forming units per unit cement area found between 24 and 30 h after inoculation. None of the gentamicin-loaded cements showed a reduction in biofilm formation relative to unloaded cements within 6 h after inoculation, whereas only gentamicin-loaded CMW1 and Palacos reduced biofilm formation 24 h after inoculation. Alternatively, CMW Endurance, CMW2000, and Palamed did not exhibit any initial reductions in biofilm formation, but effects started after 72, 48, and 72 h, respectively. Biofilm reduction by gentamicin-loaded CMW3 lasted the longest from 24 to 72 h. Interestingly, each cement seemed to have a different "window-of-effectiveness" with regard to reduction in biofilm formation that did not relate with the gentamicin-release kinetics. Summarising, this study demonstrates that although gentamicin loading of bone cements yields reductions in biofilm formation, S. aureus is able to grow on gentamicin-loaded bone cements.

Subclavian steal syndrome from high-output brachiocephalic arteriovenous fistula: a previously undescribed complication of dialysis access.

A 28-year-old dialysis-dependent man presented with episodic vertebrobasilar insufficiency. Noninvasive studies demonstrated an estimated 5.8 L/min flow through the arteriovenous fistula in his left arm and reversal of flow in the left vertebral artery. Surgical reduction of fistula flow resulted in the elimination of symptoms and the return of antegrade flow in the left vertebral artery. intraoperative invasive monitoring corroborated the pressure gradient responsible for his subclavian steal syndrome.

Infection of orthopedic implants and the use of antibiotic-loaded bone cements. A review.

Infections by bacteria are a serious complication following orthopedic implant surgery, that can usually only be cured by removing the implant, since the biofilm mode of growth of infecting bacteria on an implant surface protects the organisms from the host immune system and antibiotic therapy. Over the past few decades, attempts have been made to prevent and cure orthopedic implant infections by incorporating antibiotics in polymethylmethacrylate bone cements, in primary and revision surgery. However, the clinical efficacy of antibiotic-releasing bone cements is not accepted by all and the long-term exposure to low doses from antibiotic-releasing bone cements in patients is strongly related to the emerging threat of antibiotic resistance in medicine today. In this article, we start by reviewing the mechanisms governing the formation of an infectious biofilm on orthopedic implant materials, the release mechanisms and properties of clinically-used, antibiotic-loaded bone cements. The clinical efficacy of antibiotic-loaded bone cements is evaluated analyzing separatedly the prophylactic and therapeutic uses of these products.

Effect of fluorine substitution on the interaction of lipophilic ions with the plasma membrane of mammalian cells.

The effects of the anionic tungsten carbonyl complex [W(CO)(5)SC(6)H(5)](-) and its fluorinated analog [W(CO)(5)SC(6)F(5)](-) on the electrical properties of the plasma membrane of mouse myeloma cells were studied by the single-cell electrorotation technique. At micromolar concentrations, both compounds gave rise to an additional antifield peak in the rotational spectra of cells, indicating that the plasma membrane displayed a strong dielectric dispersion. This means that both tungsten derivatives act as lipophilic ions that are able to introduce large amounts of mobile charges into the plasma membrane. The analysis of the rotational spectra allowed the evaluation not only of the passive electric properties of the plasma membrane and cytoplasm, but also of the ion transport parameters, such as the surface concentration, partition coefficient, and translocation rate constant of the lipophilic anions dissolved in the plasma membrane. Comparison of the membrane transport parameters for the two anions showed that the fluorine-substituted analog was more lipophilic, but its translocation across the plasma membrane was slower by at least one order of magnitude than that of the parent hydrogenated anion.

Surface roughness, porosity and wettability of gentamicin-loaded bone cements and their antibiotic release.

In this study, the release of gentamicin as a function of time was measured for six different gentamicin-loaded bone cements and related with the surface roughness, porosity and wettability of the cements. Initial release rates varied little between the six bone cements (CMW1, CMW3, CMW Endurance, CMW 2000, Palacos, and Palamed) and ranged from 8.6 to 14.1 microg/cm2/h. The total amounts of gentamicin released after 1 week varied between 4.0 and 5.3% of the total amount of antibiotic incorporated for the CMW cements and was 8.4% for Palacos. Palamed released after 1 week significantly more of the gentamicin incorporated (17.0%). The wettability of all cements was similar (water contact angles between 70 and 80 degrees), but the surface roughness and the porosity of the cements varied markedly. Initial release rates increased with surface roughness, although the correlation coefficient was low (0.64), while total amounts released increased linearly (correlation coefficient 0.97) with the bulk porosity of the cements. Consequently, it can be concluded that the release kinetics of gentamicin from bone cements is controlled by a combination of surface roughness and porosity.

Gentamicin release from polymethylmethacrylate bone cements and Staphylococcus aureus biofilm formation.

We measured the formation of a Staphylococcus aureus biofilm in vitro on unloaded and gentamicin-loaded bone cements (CMW3 and Palacos R) and related the formation to antibiotic release rates. All experiments were done in triplicate. Microbial growth on gentamicin-loaded cements occurred despite the release of antibiotic. Biofilm formation on gentamicin loaded CMW3 bone cement was one fourth to one fifth less than on the unloaded bone cement, while biofilm formation on Palacos R bone cement was not significantly affected by antibiotic loading. More gentamicin was released from CMW3 (79 mg) than from Palacos R (70 mg), but the percentage gentamicin released after one week relative to the total amount incorporated was significantly lower for CMW3 (4.7%) than for Palacos R (8.4%). After one day, subinhibitory concentrations of antibiotics were eluted from the cements. We concluded that antibiotic-loaded bone cement does not necessarily inhibit the formation of an infectious biofilm in vitro.

CO2 and gadopentetate dimeglumine as alternative contrast agents for malfunctioning dialysis grafts and fistulas.

BACKGROUND: Hemodialysis grafts and native fistulas are frequently evaluated angiographically utilizing iodinated contrast material to determine the cause of malfunction. Occasionally, patients are not able to receive iodinated contrast material due to a history of previous severe allergic reaction or concern that iodinated contrast material could worsen renal function requiring premature initiation of permanent dialysis. We set out to test the feasibility of gadopentetate dimeglumine as an alternative contrast agent in conjunction with carbon dioxide (CO2) angiography in the evaluation and treatment of hemodialysis grafts and native fistulas in patients who have a contraindication to iodinated contrast material. METHODS: Six patients with a malfunctioning hemodialysis graft and native fistula were evaluated. Four patients were successfully evaluated using carbon dioxide and gadopentetate dimeglumine. Two additional patients underwent balloon angioplasty using gadopentetate dimeglumine alone as the alternative contrast agent. RESULTS: All six patients successfully were evaluated and treated using gadopentetate dimeglumine either alone or as a supplement to CO2 angiography. Five of these patients had lesions successfully treated using gadopentetate dimeglumine alone or in combination with CO2 as the angiographic contrast agents. One patient underwent a successful diagnostic angiogram using gadopentetate dimeglumine and CO2 as alternative contrast agents and was subsequently treated with surgical revision. The gadopentetate dimeglumine angiograms identified the arterial anastomosis and more clearly identified stenotic lesions and venous outflow anatomy compared to carbon dioxide angiograms. CONCLUSION: Gadopentetate dimeglumine is useful as an alternative contrast agent in conjunction with CO2 in patients with malfunctioning hemodialysis grafts and fistulas, who have a contraindication to the administration of iodinated contrast material.

Interaction of lipophilic ions with the plasma membrane of mammalian cells studies by electrorotation.

The electrical properties of biological and artificial membranes were studied in the presence of a number of negatively charged tungsten carbonyl complexes, such as [W(CO)5(CN)]- , [W(CO)5(NCS)]-, [W2(CO)10(CN)]-, and [W(CO)5(SCH2C6H5)]-, using the single-cell electrorotation and the charge-pulse relaxation techniques. Most of the negatively charged tungsten complexes were able to introduce mobile charges into the membranes, as judged from electrorotation spectra and relaxation experiments. This means that the tungsten derivatives act as lipophilic anions. They greatly contributed to the polarizability of the membranes and led to a marked dielectric dispersion (frequency dependence of the membrane capacitance and conductance). The increment and characteristic frequency of the dispersion reflect the structure, environment, and mobility of the charged probe molecule in electrorotation experiments with biological membranes. The partition coefficients and the translocation rate constants derived from the electrorotation spectra of cells agreed well with the corresponding data obtained from charge-pulse experiments on artificial lipid bilayers.

Intraoperative urinary cyclic AMP monitoring in primary hyperparathyroidism.

OBJECTIVE: This study examined the utility of intraoperative urinary cyclic 3'5' adenosine monophosphate (UcAMP), an indicator of parathyroid (PTH) hormone end-organ activity, as a "biochemical frozen section," signaling the real-time resolution of PTH hyperactivity during surgery for primary hyperparathyroidism. SUMMARY BACKGROUND DATA: The unsuccessful initial neck exploration for primary hyperparathyroidism, leaving the patient with persistent hyperfunctioning parathyroid tissue, results in part from the surgeon's inability intraoperatively to correlate a gland's gross appearance and size estimation with physiologic function. Preoperative imaging, intraoperative imaging, and intraoperative histologic/cytologic surveillance have not resolved this dilemma. METHODS: Twenty-seven patients underwent a prospective intraoperative UcAMP monitoring protocol. The patients all had a clinical diagnosis of primary hyperparathyroidism and an average preoperative serum calcium of 12.0 +/- 0.3 mg/dl. UcAMP was assayed intraoperatively using 20-minute nonequilibrium radioimmunoassay providing real-time feedback to the operating team. RESULTS: All patients had an elevated UcAMP confirming PTh hyperactivity at the beginning of the procedure. One patient, subsequently found to have an supernumerary ectopic adenoma, had four normal glands identified intraoperatively, and his intraoperative UcAMP values corroborated persistent hyperparathyroidism, the UcAMP of the remaining 26 patients decreased from 7.0 +/- 1.1 to 2.7 +/- 0.7 nm.dl GF (p < .00005) after complete adenoma excision, and they remain normocalcemic. The protocol provided useful and relevant information to the operating team, and aided in surgical decision-making, in 10 of the 27 cases (37%). CONCLUSION: Intraoperative biochemical surveillance with ucAMP monitoring reliably signals resolution of PTH hyperfunction. It is a useful adjunct to the surgeon's skill, judgment, and experience in parathyroid surgery.

Aspergillus flavus wound infection following repair of a ruptured duodenum in a non-immunocompromised host.

Aspergillus flavus is generally considered to be an opportunistic organism, rarely causing clinical infections in the immunocompetent host. We present a case of a 79-year-old man without history of immunocompromise who developed a severe aspergillus wound infection in an open wound following repair of a traumatic duodenal perforation. Despite aggressive treatment, this invasive infection contributed significantly to his eventual demise.

The effects of thyroid state on sarcomere dynamics of ventricular cells and contraction of papillary muscles in the rat heart.

Diastolic sarcomere length, amplitude of maximal sarcomere shortening, maximal rate of sarcomere shortening, maximal rate of sarcomere re-lengthening, time to peak sarcomere shortening and trans-sarcolemmal ion currents were measured in isolated ventricular cells from euthyroid, hypothyroid and hyperthyroid rats. The data were compared with the developed tension and time to peak tension of papillary muscles. The diastolic sarcomere length was not affected by the changes in thyroid state. Hypothyroidism led to an increased time to peak sarcomere shortening, an increased time to peak tension of the papillary muscle, and a depression of the maximal rates of shortening and elongation of the sarcomeres. Changes in dynamics of the sarcomere and contraction of papillary muscle did not occur in parallel under the influence of hyperthyroidism. In comparison with the euthyroid state, the time to peak tension was shortened and amplitude of shortening of the sarcomere was increased. The time to peak shortening of the sarcomere and developed tension of papillary muscle remained unaltered. In cardiac cells, hypothyroidism was associated with a decreased slow Ca2+ current and hyperthyroidism with an increased slow Ca2+ current. In contrast to euthyroid and hypothyroid cardiac cells, the hyperthyroid cardiomyocytes exhibited a trans-sarcolemmal transient inward current after repolarization. Both hypothyroidism and hyperthyroidism resulted in a depressed potentiation of sarcomere shortening and myocardial developed tension after resting.(ABSTRACT TRUNCATED AT 250 WORDS)