The effect of collisions on the rotational angular momentum of diatomic molecules studied using polarized light.

We report results of an experimental study of the changes in the alignment of the rotational angular momentum of diatomic molecules during elastic collisions. The experiment involved collisions of diatomic lithium molecules in the A1Σu + excited electronic state with noble gas atoms (helium and argon) in a thermal gas phase sample. Polarized light for excitation was combined with the detection of polarization-specific fluorescence in order to achieve magnetic sublevel state selectivity. We also report results for rotationally inelastic collisions of Li2 in the lowest lying rotational levels of the A1Σu +v=5 vibrational state with noble gas atoms.

Threshold currents of platinum electrodes used for functional electrical stimulation of the phrenic nerves for treatment of central apnea.

BACKGROUND: Stability of threshold currents during long-term use of phrenic nerve stimulation has been questioned. METHODS AND RESULTS: Between January 5, 1988, and March 5, 2008, 49 patients with functional C2-tetraplegia received an Atrostim PNS (Atrotech Ltd., Tampere, Finland) as treatment of their respiratory insufficiency; a follow-up of 35 of such patients was carried out exclusively in our institution for 6.3 (4.44) 0.04-15.75 years (mean [standard deviation (SD)] range). The device employed four-pole sequential nerve stimulation, which provided four threshold currents subsequently evaluated for each phrenic nerve. Stimulation data were prospectively recorded. The differences between threshold currents recorded 1 year after implantation and the last recorded values were 0.33-0.43 (0.44-0.63) 0-2.9 mA. After having excluded the data of eight patients with values >1 mA (= mean + SD), we registered the differences for the remaining patients of 0.15-0.24 (0.14-0.24) 0-0.95 mA, which is just twice the adjustment accuracy of the device. Out of the eight problem cases one had, and two were suspected to have, surgical trauma; all three nerves recovered. In two cases the values steadily increasing over years might have been caused by unspecific foreign body reaction. Two cases with values >1 mA for different durations at different electrodes might be caused by biofilm, and one patient displaying steadily increasing values lived, unwilling to live, only 2 years after the implantation. CONCLUSION: Thus, there was no permanent nerve injury and in 77% of the presented cases threshold currents remained stable.

Sources of information influencing decision-making in orthopaedic surgery - an international online survey of 1147 orthopaedic surgeons.

BACKGROUND: Manufacturers of implants and materials in the field of orthopaedics use significant amounts of funding to produce informational material to influence the decision-making process of orthopaedic surgeons with regards to choice between novel implants and techniques. It remains unclear how far orthopaedic surgeons are really influenced by the materials supplied by companies or whether other, evidence-based publications have a higher impact on their decision-making. The objective was to evaluate the subjective usefulness and usage of different sources of information upon which orthopaedic surgeons base their decisions when acquiring new implants or techniques. METHODS: We undertook an online survey of 1174 orthopaedic surgeons worldwide (of whom n = 305 were head of their department). The questionnaire included 34 items. Sequences were randomized to reduce possible bias. Questions were closed or semi-open with single or multiple answers. The usage and relevance of different sources of information when learning about and selecting orthopaedic treatments were evaluated. Orthopaedic surgeons and trainees were targeted, and were only allowed to respond once over a period of two weeks. Baseline information included country of workplace, level of experience and orthopaedic subspecialisation. The results were statistically evaluated. RESULTS: Independent scientific proof had the highest influence on decisions for treatment while OEM (Original Equipment Manufacturer) driven activities like newsletters, white papers or workshops had the least impact. Comparison of answers from the three best-represented countries in this study (Germany, UK and USA) showed some significant differences: Scientific literature and congresses are significantly more important in the US than in the UK or Germany, although they are very important in all countries. CONCLUSIONS: Independent and peer-reviewed sources of information are preferred by surgeons when choosing between methods and implants. Manufacturers of medical devices in orthopaedics employ a considerable workforce to inform or influence hospital managers and leading doctors with marketing activities. Our results indicate that it might be far more effective to channel at least some of these funds into peer-reviewed research projects, thereby assuring significantly higher acceptance of the related products.

Biomechanical testing of a new plate system for the distal humerus compared to two well-established implants.

PURPOSE: A biomechanical study was performed to test the hypothesis that a new anatomically preformed, thinner, soft-tissue protecting plate system for distal humeral fractures (Tifix®-hybridplate [HP]) would show comparable results in the quasi-static and dynamic testings compared to two conventional implants: The 3.5-mm reconstruction plate (RP) providing primary stability with normal bone mineral density (BMD), and a multidirectional locking plate (Tifix(®)-plate [P]) which can be used with poor bone quality. METHODS: The Tifix(®)-HP was developed by the working group. The biomechanical testing was performed on a C2-fracture-model in 24 synthetic humeri. Three groups, each with eight bone-implant-constructs, were analysed in quasi-static and dynamic tests. RESULTS: The quasi-static measurements showed that under extension loading both locking plates (Tifix(®)-P, Tifix(®)-HP) were significantly stiffer than the reconstruction plate, and that the Tifix(®)-HP had a significantly lower stiffness than the two other implants under flexion loading. In the dynamic tests the Tifix(®)-P allowed significantly less fracture motion compared to the Tifix(®)-HP and the reconstruction plate. In an osteopaenic bone model locking plates failed only under much higher dynamic force than the reconstruction plate. The reconstruction plate and the Tifix(®)-P always failed through screw loosening, whereas the newly developed Tifix(®)-HP showed screw loosening in only one third of cases. CONCLUSION: The hypothesis that the newly designed plate system showed comparable results in the quasi-static and dynamic tests compared to the conventional implants with a significantly lower implant volume and thickness was confirmed.

Demographics and functional outcome of shallow water diving spinal injuries in northern Germany - A retrospective analysis of 160 consecutive cases.

AIM: To describe demographic findings, typical injuries and functional neurological outcomes in patients with cervical trauma and tetraplegia sustained after diving into shallow water. PATIENTS AND METHODS: A retrospective study was performed including all patients treated in BG Klinikum Hamburg suffering from tetraplegia after jumping into shallow water between 1st June 1980 and 31st July 2018. RESULTS: One hundred and sixty patients with cervical spinal injuries and tetraplegia following a dive into shallow water were evaluated. Of these, 156 patients (97.5%) were male. The mean age was 24.3 years ± 8.1 and the accidents occurred most often in inland waters (56.2%) and mostly between May and August (90.6%). In all cases there was one vertebra fractured, whereas in 48.1% of cases, two vertebrae were severed. In the majority of cases (n = 146), a surgical procedure was performed. Overall, the mean hospital stay was 202 days (±72, range: 31-403) and one patient died. On admission, 106 patients (66.2%) showed a complete lesion according to AIS A, with incomplete lesions in the remaining 54 patients (AIS B: n = 25 [15.6%], AIS C: n = 26 [16.3%], AIS D: n = 3 [1.9%]). In two thirds of the patients, the level of paralysis on admission was at the level of segments C4 (31.9%) or C5 (33.7%). Seventeen patients (10.6%) needed prehospital resuscitation. In 55 patients (34.4%), the neurological findings improved during the course of inpatient treatment and rehabilitation. Sixty-eight patients (42.5%) developed pneumonia, of which 52 patients (76.5%) were ventilated. In addition, 56.5% of patients with paralysis levels C0-C3 required ventilation, whereas only 6.3% of patients with paralysis levels C6-C7 were affected. Three patients (1.9%) were discharged from hospital with continuous ventilation. Overall, 27.4% of all AIS A patients, 56% of all AIS B patients and 46.2% of all AIS C patients improved neurologically, with 17% of all patients being able to walk. CONCLUSIONS: The consequences of a cervical spine injury after diving into shallow water are severe and lifelong. Functionally, patients may benefit from care in a specialised centre, both in the acute phase and during rehabilitation. The more incomplete the primary paralysis, the greater the possibility of neurological recovery.

Intramedullary Nailing vs Sliding Hip Screw in Trochanteric Fracture Management: The INSITE Randomized Clinical Trial.

Importance: Fractures of the hip have devastating effects on function and quality of life. Intramedullary nails (IMN) are the dominant implant choice for the treatment of trochanteric fractures of the hip. Higher costs of IMNs and inconclusive benefit in comparison with sliding hip screws (SHSs) convey the need for definitive evidence. Objective: To compare 1-year outcomes of patients with trochanteric fractures treated with the IMN vs an SHS. Design, Setting, and Participants: This randomized clinical trial was conducted at 25 international sites across 12 countries. Participants included ambulatory patients aged 18 years and older with low-energy trochanteric (AO Foundation and Orthopaedic Trauma Association [AO/OTA] type 31-A1 or 31-A2) fractures. Patient recruitment occurred between January 2012 and January 2016, and patients were followed up for 52 weeks (primary end point). Follow-up was completed in January 2017. The analysis was performed in July 2018 and confirmed in January 2022. Interventions: Surgical fixation with a Gamma3 IMN or an SHS. Main Outcomes and Measures: The primary outcome was health-related quality of life (HRQOL), measured by the EuroQol-5 Dimension (EQ5D) at 1-year postsurgery. Secondary outcomes included revision surgical procedure, fracture healing, adverse events, patient mobility (measured by the Parker mobility score), and hip function (measured by the Harris hip score). Results: In this randomized clinical trial, 850 patients were randomized (mean [range] age, 78.5 [18-102] years; 549 [64.6% female) with trochanteric fractures to undergo fixation with either the IMN (n = 423) or an SHS (n = 427). A total of 621 patients completed follow-up at 1 year postsurgery (304 treated with the IMN [71.9%], 317 treated with an SHS [74.2%]). There were no significant differences between groups in EQ5D scores (mean difference, 0.02 points; 95% CI, -0.03 to 0.07 points; P = .42). Furthermore, after adjusting for relevant covariables, there were no between-group differences in EQ5D scores (regression coefficient, 0.00; 95% CI, -0.04 to 0.05; P = .81). There were no between-group differences for any secondary outcomes. There were also no significant interactions for fracture stability (ß [SE] , 0.01 [0.05]; P = .82) or previous fracture (ß [SE], 0.01 [0.10]; P = .88) and treatment group. Conclusions and Relevance: This randomized clinical trial found that IMNs for the treatment of trochanteric fractures had similar 1-year outcomes compared with SHSs. These results suggest that the SHS is an acceptable lower-cost alternative for trochanteric fractures of the hip. Trial Registration: ClinicalTrials.gov Identifier: NCT01380444.

One-screw fixation provides similar stability to that of two-screw fixation for type II dens fractures.

BACKGROUND: Anterior screw fixation has been widely adopted for the treatment of type II dens fractures. However, there is still controversy regarding whether one- or two-screw fixation is more appropriate. QUESTIONS/PURPOSES: We addressed three questions: (1) Do one- and two-screw fixation techniques differ regarding shear stiffness and rotational stiffness? (2) Can shear stiffness and rotational stiffness after screw fixation be restored to normal? (3) Does stiffness after screw fixation correlate with bone mineral density (BMD)? METHODS: We randomly assigned 14 fresh axes into two groups (seven axes each): one receiving one-screw fixation and another receiving two-screw fixation. Shear and torsional stiffness were measured using a nondestructive low-load test in six directions. A transverse osteotomy then was created at the base of the dens and fixed using one or two screws. Shear and torsional stiffness were tested again under the same testing conditions. RESULTS: Mean stiffness in all directions after screw fixation was similar in both groups. The stiffness after one- and two-screw fixation was not restored to normal: the mean shear stiffness restored ratio was less than 50% and the mean torsional stiffness restored ratio was less than 6% in both groups. BMD did not correlate with mean stiffness after screw fixation in both groups. CONCLUSIONS: One- and two-screw fixation for type II dens fractures provide similar stability but neither restores normal shear or torsional stiffness. CLINICAL RELEVANCE: One-screw fixation might be used as an alternative to two-screw fixation. Assumed BMD should not influence surgical decision making.

Early functional results after hemiarthroplasty for femoral neck fracture: a randomized comparison between a minimal invasive and a conventional approach.

BACKGROUND: A minimal invasive approach for elective hip surgery has been implemented in our institution in the past. It is widely hypothesized that implanting artificial hips in a minimal invasive fashion decreases surgical trauma and is helpful in the rehabilitation process in elective hip surgery. Thereby geriatric patients requiring emergency hip surgery also could theoretically benefit from a procedure that involves less tissue trauma. METHODS: Sixty patients who sustained a fractured neck of femur were randomly assigned into two groups. In the minimal invasive arm, the so called "direct anterior approach" (DAA) was chosen, in the conventional arm the Watson-Jones-Approach was used for implantation of a bipolar hemi-arthroplasty.Primary outcome parameter was the mobility as measured by the four-item-Barthel index. Secondary outcome parameters included pain, haemoglobin-levels, complications, duration of surgery, administration of blood transfusion and external length of incision. Radiographs were evaluated. RESULTS: A statistically significant difference (p = 0,009) regarding the mobility as measured with the four-item Barthel index was found at the 5th postoperative day, favouring the DAA. Evaluation of the intensity of pain with a visual analogue scale (VAS) showed a statistically significant difference (p = 0,035) at day 16. No difference was evident in the comparison of radiographic results. CONCLUSIONS: Comparing two different approaches to the hip joint for the implantation of a bipolar hemi-arthroplasty after fractured neck of femur, it can be stated that mobilization status is improved for the DAA compared to the WJA when measured by the four-item Barthel index, there is less pain as measured using the VAS. There is no radiographic evidence that a minimal invasive technique leads to inferior implant position. LEVEL OF EVIDENCE: Level II therapeutic study.

Haemolytic anaemia and renal failure associated with antibodies to trimethoprim and sulfamethoxazole.

AIM: The aim of this study was to support a clinical diagnosis of drug-induced immune haemolytic anaemia (DIIHA). BACKGROUND: DIIHA is rare and has only been described twice with the antibiotic combination of trimethoprim (TMP) and sulfamethoxazole (SMX). METHODS/MATERIALS: Serologic tests for drug antibodies were performed using methods previously published by our laboratory. RESULTS: A 44-year-old woman experienced body aches, chills, chest pressure, nausea and a rash while receiving TMP-SMX; a week later her haemoglobin was low and she was in renal failure. At the hospital, the direct antiglobulin test (DAT) was positive (C3 only) and the serum reacted with all red blood cells (RBCs) by the gel method only (TMP-SMX is present in the RBC diluent used for the gel method). At the Red Cross immunohaematology laboratory, the patient's serum was reactive in the presence of TMP-SMX (haemolysis and positive antiglobulin test), pure TMP (positive antiglobulin test using anti-IgG only) and pure SMX (haemolysis and positive antiglobulin test using both anti-IgG and anti-C3). The patient was treated with transfusions and haemodialysis and was discharged after a week in stable condition. CONCLUSION: We describe a patient who appeared to have haemolytic anaemia and renal failure associated with antibodies to both TMP and SMX.

Long-Term Survival and Causes of Death in Patients below the Age of 60 with Traumatic Spinal Cord Injury in Germany.

To study the mortality, cause and risk indicators of death in German patients with traumatic spinal cord injury, patients with traumatic spinal cord injury admitted to Berufsgenossenschaftliches Trauma Hospital Hamburg between 1 January 1997 and 31 December 2018, aged between 16 and 60 with a minimal survival of one year after injury, were included. Further criteria were the absence of life-limiting comorbidities at the time of injury. 223 deceased patients with traumatic spinal cord injury were identified, investigated on and partly compared to the surviving subjects. We aimed to discover specific complications that were related to Spinal Cord Injury and responsible for a possibly limited life expectancy. Data collection was performed during in- and outpatient treatment. A statistical analysis was performed to compare groups. The post-injury life expectancy was 25.0 years with a significant correlation regarding the level of lesion and severity of injury. The leading causes of death were cardiovascular diseases and pneumonia. Bladder cancer was the most common fatal malignant tumor. The life expectancy of patients suffering from traumatic spinal cord injury is limited. The longer a patient survives after injury and the lower the level of lesion, the more likely an age-related cause of death becomes. Bladder cancer is significantly more frequent when compared to the overall distribution of tumor diseases in Germany.

Lag-Screw Osteosynthesis in Thoracolumbar Pincer Fractures.

STUDY DESIGN: Biomechanical. OBJECTIVE: This study evaluates the biomechanical properties of lag-screws used in vertebral pincer fractures at the thoracolumbar junction. METHODS: Pincer fractures were created in 18 bisegmental human specimens. The specimens were assigned to three groups depending on their treatment perspective, either bolted, with the thread positioned in the cortical or cancellous bone, or control. The specimens were mounted in a servo-hydraulic testing machine and loaded with a 500 N follower load. They were consecutively tested in 3 different conditions: intact, fractured, and bolted/control. For each condition 10 cycles in extension/flexion, torsion, and lateral bending were applied. After each tested condition, a computed tomography (CT) scan was performed. Finally, an extension/flexion fatigue loading was applied to all specimens. RESULTS: Biomechanical results revealed a nonsignificant increase in stiffness in extension/flexion of the fractured specimens compared with the intact ones. For lateral bending and torsion, the stiffness was significantly lower. Compared with the fractured specimens, no changes in stiffness due to bolting were discovered. CT scans showed an increasing fracture gap during axial loading both in extension/flexion, torsion, and lateral bending in the control specimens. In bolted specimens, the anterior fragment was approximated, and the fracture gap nullified. This refers to both the cortical and the cancellous thread positions. CONCLUSION: The results of this study concerning the effect of lag-screws on pincer fractures appear promising. Though there was little effect on stiffness, CT scans reveal a bony contact in the bolted specimens, which is a requirement for bony healing.

Clinical results of resection arthrodesis by triangular external fixation for posttraumatic arthrosis of the ankle joint in 89 cases.

UNLABELLED: The methods for ankle arthrodesis differ significantly, probably a sign that no method is clearly superior to others. In the last ten years there is a clear favour toward internal fixation. We retrospectively evaluate the technique and evaluate the clinical long term results of external fixation in a triangular frame. PATIENTS AND METHODS: From 1994 to 2001 a consecutive series of 95 patients with end stage arthritis of the ankle joint were treated. Retrospectively the case notes were evaluated regarding trauma history, medical complaints, further injuries and illnesses, walking and pain status and occupational issues and the clinical examination before arthrodesis. Mean age at the index procedure was 45.4 years (18-82), 67 patients were male (70.5%). Via a bilateral approach the malleoli and the joint surfaces were resected. An AO fixator was applied with two Steinmann-nails inserted with approximately 8 cm distance in the distal tibia, one in the neck of the talus and one in the dorsal calcaneus. The fixator was removed after approximately 12 weeks. Follow up examination at mean 4.4 years included a standardised questionnaire and a clinical examination including the criteria of the AOFAS-Score and radiographs. RESULTS: Due to different complications, 8 (8.9%) further surgical procedures were necessary including 1 below knee amputation. In 4 patients a non-union of the ankle arthrodesis developed (4.5%). The mean AOFAS score improved from 20.8 to 69.3 points. CONCLUSION: Non-union rates and clinical results of arthrodesis by triangular external fixation of the ankle joint do not differ to internal fixation methods. The complication rate and the reduced patient comfort reserve this method mainly for infected arthritis and complicated soft tissue situations.

[The Valenti resection arthroplasty in the treatment of advanced hallux rigidus]. / Die Resektionsarthroplastik nach Valenti zur Behandlung des fortgeschrittenen Hallux rigidus.

OBJECTIVE: With this joint-preserving procedure impinging and damaged parts of the first metatarsal head and the proximal phalanx are removed. The attachment of the short flexor tendon is preserved. Joint motion will increase and joint function is preserved. INDICATIONS: Hallux rigidus stage 2-3 according to the Vanore classification. Salvage procedure for failed arthroplasty of the first metatarsophalangeal joint. CONTRAINDICATIONS: Hallux rigidus stage 4 according to the Vanore classification. Severe elevatus position of first ray. SURGICAL TECHNIQUE: Surgery with tourniquet is preferred. Dorsomedial skin incision. Longitudinal incision of the capsule. Removal of medial and lateral osteophytes both from the metatarsal and the proximal phalanx. Release of the sesamoids. Removal of the dorsal osteophytes from the metatarsal head and the proximal phalanx in a 45 degrees angle. Intraoperative dorsiflexion should be at least 75 degrees. Hourglass tightening of the capsule at joint level. POSTOPERATIVE MANAGEMENT: Active and passive exercises immediately after surgery. Full weight bearing is allowed. Tape in forefoot pronation if marked relieving posture. RESULTS: Follow-up study of 162 patients. Follow-up period at least 2 years (24-38 months). Increase in dorsiflexion by 27 degrees. 80% of the patients temporarily showed pain at the sesamoids. Twelve patients with progression of the osteoarthritis underwent implant arthroplasty of the first metatarsophalangeal joint (n = 10) or a fusion of the joint (n = 2) as salvage surgery. Fusion or implant arthroplasty of the first metatarsophalangeal joint could be avoided primarily. In comparison to the relevant literature the results are superior to a cheilectomy.

Dehydropolymerisation of methylamine borane using a dinuclear 1,3-allenediyl bridged zirconocene complex.

The dinuclear zirconocene chloride complex 1 is a highly active precatalyst for the dehydropolymerisation of methylamine borane. Comparison with mononuclear Zr chlorides and related dinuclear complexes suggests that the nature of the bridging motif is essential for the unique reactivity of 1.

Artificial urine and FBS supplemented media in cytocompatibility assays for PLGA-PEG-based intravesical devices using the urothelium cell line UROtsa.

European and German directives for approval of new medical devices require tests for cytotoxicity in relevant media, since urine can influence cytotoxicity of biodegradable devices. The aim of this study was to determine the long-term cytotoxicity of PLGA-b-mPEG (PLGA-PEG) polymer carriers and artificial urine (AU) to human UROtsa cells. Benign urothelial UROtsa cells were incubated in fetal bovine serum-containing RPMI 1640 medium supplemented with a range of concentrations of AU for 24 h and 7 days. Cell viability was determined by the XTT assay and by live/dead staining. The cytotoxicity of medium containing degradation products from PLGA-PEG carriers was also tested on the UROtsa cells in AU-containing and control medium. PLGA-PEG carriers exhibited no cytotoxicity to UROtsa cells after 24 h of incubation. However, after 7 days, cytotoxicity was observed, but this was largely attributable to the effects of 30% AU on the cells. Compared to phosphate buffer saline (PBS) and normalized to RPMI 1640 medium, significant cytotoxicity was observed by 24 h in medium containing 50% AU and by 7 days in medium containing 30% AU. Live/Dead staining confirmed proliferation results and no pH-changes could be observed. Here we demonstrate for the first time the impact of AU on standard cytotoxicity tests related to biomaterials for urinary-tract applications. Our study showed cytotoxic effects of high concentrations of 50% AU by 24 h and by physiological concentrations of AU (i.e., 30%) by 7 days. We have also demonstrated that PLGA-PEG has no cytotoxic effects in the appropriate AU-containing test environment. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2140-2147, 2018.

Septic arthritis of the knee after anterior cruciate ligament surgery: a stage-adapted treatment regimen.

BACKGROUND: Septic arthritis is a rare complication after anterior cruciate ligament surgery. All case series reported so far have been retrospective, and case numbers of septic arthritis have ranged from 4 to 11. HYPOTHESIS: A stage-adapted treatment regimen for septic arthritis after anterior cruciate ligament surgery can provide reliable results. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: From June 1993 to May 2003, 24 patients met the inclusion criteria for this study. The average age at trauma was 32.5 years. Treatment protocol was based on the grade of infection. Options included transarthroscopic treatment for Gaechter grades 1 and 2 infections or medial and lateral arthrotomy for grades 3 and 4 infections. Graft retention was decided based on clinical findings. The setting was a specialized trauma hospital. Follow-up included International Knee Documentation Committee forms, radiographs, and the Tegner and Lysholm scores at a mean of 66 months (range, 11-142) after treatment. RESULTS: In all cases, treatment of infection was successful; overall, a mean of 2.2 operations were required. In 7 cases, it was possible to salvage the graft. The Tegner activity level before the knee injury was 6.1 points. At follow-up, the average score was 3.8 points. The postoperative subjective International Knee Documentation Committee score averaged 64. The mean Lysholm score was 65.6. On clinical examination, a mean extension deficit of 3 degrees and a mean maximum flexion of 120 degrees were found. In the single-legged hop test, a mean capacity of 63% compared with the uninjured side was measured. CONCLUSION: The described treatment regimen gives reliable results for this complication. There were no recurrences of septic arthritis or bone infection. Early infection can be managed arthroscopically with satisfactory results regarding the treatment of infection. In advanced or chronic infection, a more radical approach seems favorable. Results in these cases are overall only fair compared with patients with an uncomplicated anterior cruciate ligament reconstruction.

Biomechanical evaluation of novel ultrasound-activated bioresorbable pins for the treatment of osteochondral fractures compared to established methods.

BACKGROUND: Osteochondral injuries often lead to osteoarthritis of the affected joint. All established systems for refixation of osteochondral defects show certain disadvantages. To address the problem of reduced stability in resorbable implants, ultrasound-activated pins were developed. By ultrasound-activated melting of the tip of these implants, a more secure anchoring is assumed. MATERIALS AND METHODS: The aim of the study was to investigate if ultrasound-activated pins can provide secure fixation of osteochondral fragments compared to screws and conventional resorbable pins. In a biomechanical laboratory setting, osteochondral fragments of the medial femoral condyle of sheep were refixated with ultrasound-activated pins [US fused poly(L-lactide-co-D,L-lactide) (PLDLLA) pins], polydioxanone (PDA) pins and conventional titanium screws. Anchoring forces of the different fixation methods were examined, registered and compared concerning shear force and tensile force. RESULTS: Concerning the pull out test, the US fused PLDLLA pins and titanium screws (~122 N and ~203 N) showed comparable good results, while the PDA pins showed significantly lower anchoring forces (~18 N). Examination of shear forces showed a significantly higher anchoring of the screws (~248 N) than the US fused PLDLLA pins (~218 N). Nevertheless, the US fused PLDLLA pins could significantly outperform the PDA pins (~68 N) concerning shear forces. CONCLUSION: The US fused PLDLLA pins demonstrated a comparable anchorage to the fixation with screws, but were free from the disadvantages of metal implants, i.e. the need for implant removal. The PDA pin application showed inferior biomechanical properties.

Cardial gunshot injury: treatment in a trauma hospital without a cardiac unit.

Gunshot injuries to the chest often require urgent admission to the nearest hospital, because of the cardiorespiratory status, transfer to a hospital without a cardiothoracic unit might be unsafe. In this case, a male patient was transferred to the nearest hospital on being shot through the heart. On admission, he was in shock, and immediate surgery was performed. We report our treatment regime for thoracic injuries and the specific management of this patient. We conclude that every hospital with an accident and emergency department has to be prepared for such an injury and that operative management is possible without cardiopulmonary bypass.

The transport modifier RS1 is localized at the inner side of the plasma membrane and changes membrane capacitance.

Previously we cloned membrane associated (M(r) 62000-67000) polypeptides from pig (pRS1), rabbit (rbRS1) and man (hRS1) which modified transport activities that were expressed in Xenopus laevis oocytes by the Na(+)-D-glucose cotransporter SGLT1 and/or the organic cation transporter OCT2. These effects were dependent on the species of RS1 and on the target transporters. hRS1 and rbRS1 were shown to be intronless single copy genes which are expressed in various tissues and cell types. Earlier immunohistochemical data with a monoclonal IgM antibody suggested an extracellular membrane association of RS1. In the present paper antibodies against recombinant pRS1 were raised and the distribution and membrane localization of RS1 reevaluated. After subcellular fractionation of renal cortex RS1 was found associated with brush border membranes and an about 1:200 relation between RS1 and SGLT1 protein was estimated. Also after overexpression in X. laevis oocytes RS1 was associated with the plasma membrane, however, at variance to the kidney it was also observed in the cytosol. Labeling experiments with covalently binding lipid-permeable and lipid-impermeable biotin analogues showed that RS1 is localized at the inner side of the plasma membrane. Western blots with plasma membranes from Xenopus oocytes revealed that SGLT1 protein in the plasma membrane was reduced when hRS1 was coexpressed with human SGLT1 which leads to a reduction in V(max) of expressed glucose transport. Measurements of membrane capacitance and electron microscopic inspection showed that the expression of hRS1 leads to a reduction of the oocyte plasma membrane surface. The data suggest that RS1 is an intracellular regulatory protein that associates with the plasma membrane. Overexpression of RS1 may effect the incorporation and/or retrieval of transporters into the plasma membrane.

Mycoplasma pneumoniae-associated bronchiolitis causing severe restrictive lung disease in adults: report of three cases and literature review.

STUDY OBJECTIVES: To characterize adult Mycoplasma pneumoniae-induced bronchiolitis requiring hospitalization. DESIGN: We encountered an adult patient with severe bronchiolitis in the absence of pneumonia due to M. pneumoniae. To determine the relative frequency of such a condition, we retrospectively reviewed the medical records of adults over a 4-year period with a hospital discharge diagnosis of "bronchiolitis" from a university hospital. SETTING: University Hospital of the University of Colorado Health Sciences Center, Denver, CO. STUDY SUBJECTS: From 1994 to 1998, 10 adult inpatients were identified with a diagnosis of bronchiolitis. There were two with respiratory bronchiolitis, one with panbronchiolitis, one patient with bronchiolitis obliterans organizing pneumonia (BOOP), and six with acute inflammatory bronchiolitis. Including the initial patient, three had a definitive clinical diagnosis of Mycoplasma-associated bronchiolitis. RESULTS: The three adult patients with bronchiolitis due to M. pneumoniae are unusual because they occurred in the absence of radiographic features of a lobar or patchy alveolar pneumonia. Hospital admission was occasioned by the severity of symptoms and gas exchange abnormalities. One patient had bronchiolitis as well as organizing pneumonia (BOOP) that responded favorably to corticosteroid treatment. The other two had high-resolution CT findings diagnostic of an acute inflammatory bronchiolitis. One of the patients with inflammatory bronchiolitis had an unusual pattern of marked ventilation and perfusion defects localized predominantly to the left lung. All three had restrictive ventilatory impairment on physiologic testing. CONCLUSIONS: In adults, Mycoplasma-associated bronchiolitis without pneumonia is rarely reported, but in hospitalized patients, it may be more common than expected and may be associated with severe physiologic disturbances.