Core decompression and alendronate treatment of the osteonecrotic rat femoral head: computer-assisted analysis

Femoral head avascular necrosis is a process leading to femoral head deformity and osteoarthritic changes in the hip joint. Alendronate slows down bone resorption and remodelling in rats, while core decompression hastens the healing processes. We evaluated the influence of daily alendronate treatment on the rat femoral head shape after surgical osteonecrosis with core decompression, compared with controls. No differences were found in shape factor and femoral head height/length ratios. It was concluded that alendronate treatment slows down the process of replacing osteonecrotic bone by new bone and prevents early immature new bone collapse resulting from early revascularization because of core decompression.

Mini-ventilation for improved oxygenation during lung resection surgery

Lung separation is frequently used during lung resection to facilitate surgery and hypoxaemia may occur because of increasing pulmonary shunt. In this study, we tested a method of mini-ventilation to the non-dependent lung and compared it to continuous positive airway pressure (CPAP) to improve oxygenation during lung resection. Thirty-eight adult patients participated in this randomised, single-blinded crossover study. Following lung separation, mini-ventilation and CPAP of 5 cmH2O were alternately applied every 15 minutes to the non-dependent lung. Mini-ventilation was performed by a portable time-cycled ventilator with a respiratory rate of 8 breaths/minute and a tidal volume of 0.1 to 0.15 l. Arterial blood gases, peak inspiratory pressure, the dynamic compliance in the dependent lung and the surgeon's evaluation of the surgical field exposure were recorded. The arterial oxygen partial pressure was significantly higher during mini-ventilation compared to CPAP (379 vs 228 mmHg). No difference was noted in the dependent lung peak inspiratory pressure or in the dynamic compliance. The surgical conditions were similar with both methods in 53% of the patients, while the surgeon preferred CPAP in 44% and mini-ventilation in 3%. In conclusion, mini-ventilation is a simple method which improves oxygenation during lung resection. However due to interference with surgical field exposure, it should be reserved for cases in which CPAP does not relieve hypoxaemia.

Delayed awakening following inadvertent high-dose remifentanil infusion in a 13 year old patient

We report the case of a 13 year old patient who received 3.0 mg of remifentanil during a 50-minute surgical procedure as a result of a dosage miscalculation. The patient failed to awaken at the conclusion of the procedure and showed signs of opioid overdose. She recovered spontaneously two hours later.

[Anesthesia and peri-operative care of the elderly patient]

With raised life expectancy, there is a constant elevation in the percentage of elderly people in the general population. Consequently, the age of the surgical patient increases. This progressive process results in operating on patients who were considered 'too old for surgery' a decade ago. There are many physiological and pathological changes that take place in all body systems during aging. The function capacity of organs deteriorates, resulting in decreased capability to overcome surgical stress. As a result, the elderly surgical patients have higher rates of peri-operative morbidity and mortality. Anesthesia and peri-operative care should be customized to this population. Practicing management of older patients undergoing surgery will increase the experience of all caregivers and, in time, improve outcome.

Factors important in evolutionary shaping of immunoglobulin gene loci

Background

The extraordinary diversity characterizing the antibody repertoire is generated by both evolution and lymphocyte development. Much of this diversity is due to the existence of immunoglobulin (Ig) variable region gene segment libraries, which were diversified during evolution and, in higher vertebrates, are used in generating the combinatorial diversity of antibody genes. The aim of the present study was to address the following questions: What evolutionary parameters affect the size and structure of gene libraries? Are the number of genes in libraries of contemporary species, and the corresponding gene locus structure, a random result of evolutionary history, or have these properties been optimized with respect to individual or population fitness? If a larger number of genes or different genome structures do not increase the fitness, then the current structure is probably optimized.

Results

We used a simulation of variable region gene library evolution. We measured the effect of different parameters on gene library size and diversity, and the corresponding fitness. We found compensating relationships between parameters, which optimized Ig library size and diversity.

Conclusions

We conclude that contemporary species' Ig libraries have been optimized by evolution in terms of Ig sequence lengths, the number and diversity of Ig genes, and antibody-antigen affinities.

Ig gene diversification and selection in follicular lymphoma, diffuse large B cell lymphoma and primary central nervous system lymphoma revealed by lineage tree and mutation analyses

Follicular lymphoma (FL), diffuse large B cell lymphoma (DLBCL) and primary central nervous system lymphoma are B cell malignancies. FL and DLBCL have a germinal center origin. We have applied mutational analyses and a novel algorithm for quantifying shape properties of mutational lineage trees to investigate the nature of the diversification, somatic hypermutation and selection processes that affect B cell clones in these malignancies and reveal whether they differ from normal responses. Lineage tree analysis demonstrated higher diversification and mutations per cell in the lymphoma clones. This was caused solely by the longer diversification times of the malignant clones, as their recent diversification processes were similar to those of normal responses, implying similar mutation frequencies. Since previous analyses of antigen-driven selection were shown to yield false positives, we performed a corrected analysis of replacement and silent mutation patterns, which revealed selection against replacement mutations in the framework regions, responsible for the structural integrity of the B cell receptor, but not for positive selection for replacements in the complementary determining regions. Most replacements, however, were neutral or conservative, suggesting that if at all selection operates in these malignancies it is for structural B cell receptor integrity but not for antigen binding.

Somatic hypermutation and antigen-driven selection of B cells are altered in autoimmune diseases

B cells have been found to play a critical role in the pathogenesis of several autoimmune (AI) diseases. A common feature amongst many AI diseases is the formation of ectopic germinal centers (GC) within the afflicted tissue or organ, in which activated B cells expand and undergo somatic hypermutation (SHM) and antigen-driven selection on their immunoglobulin variable region (IgV) genes. However, it is not yet clear whether these processes occurring in ectopic GCs are identical to those in normal GCs. The analysis of IgV mutations has aided in revealing many aspects concerning B cell expansion, mutation and selection in GC reactions. We have applied several mutation analysis methods, based on lineage tree construction, to a large set of data, containing IgV productive and non-productive heavy and light chain sequences from several different tissues, to examine three of the most profoundly studied AI diseases - Rheumatoid Arthritis (RA), Multiple Sclerosis (MS) and Sjögren's Syndrome (SS). We have found that RA and MS sequences exhibited normal mutation spectra and targeting motifs, but a stricter selection compared to normal controls, which was more apparent in RA. SS sequence analysis results deviated from normal controls in both mutation spectra and indications of selection, also showing differences between light and heavy chain IgV and between different tissues. The differences revealed between AI diseases and normal control mutation patterns may result from the different microenvironmental influences to which ectopic GCs are exposed, relative to those in normal secondary lymphoid tissues.

Evidence for large diversity in the human transcriptome created by Alu RNA editing

Adenosine-to-inosine (A-to-I) RNA editing alters the original genomic content of the human transcriptome and is essential for maintenance of normal life in mammals. A-to-I editing in Alu repeats is abundant in the human genome, with many thousands of expressed Alu sequences undergoing editing. Little is known so far about the contribution of Alu editing to transcriptome complexity. Transcripts derived from a single edited Alu sequence can be edited in multiple sites, and thus could theoretically generate a large number of different transcripts. Here we explored whether the combinatorial potential nature of edited Alu sequences is actually fulfilled in the human transcriptome. We analyzed datasets of editing sites and performed an analysis of a detailed transcript set of one edited Alu sequence. We found that editing appears at many more sites than detected by earlier genomic screens. To a large extent, editing of different sites within the same transcript is only weakly correlated. Thus, rather than finding a few versions of each transcript, a large number of edited variants arise, resulting in immense transcript diversity that eclipses alternative splicing as mechanism of transcriptome diversity, although with less impact on the proteome.

Patients aged 80 and older undergoing orthopedic or urologic surgery: a prospective study focusing on perioperative morbidity and mortality

BACKGROUND

The population is progressively aging and an increasing number of elderly patients face surgical treatment.

OBJECTIVE

The current study was designed to examine the perioperative morbidity and mortality of elderly patients undergoing orthopedic or urologic surgery and look for predictors for adverse outcome.

METHODS

This is a prospective study of elderly patients, 80 years of age and older, who underwent elective or emergent orthopedic or urologic surgery in our institution during a 5-month period. Data were collected on age, gender, chronic diseases, number of regular medications, whether or not the patient was bedridden before surgery, American Society of Anesthesiologists (ASA) class, type of surgery and anesthesia, duration of hospitalization, and 30-day postoperative morbidity and mortality. We studied correlations between pre- and intraoperative parameters and postoperative complications.

RESULTS

During the study period, 39 patients underwent urologic surgery and 147 patients underwent orthopedic surgery. Age ranged from 80 to 98 years (85 +/- 4.2 years, mean +/- SD). One patient had an intraoperative complication, 5 patients had postoperative complications within 1 day of surgery, and 23 had complications within 1 month of surgery. Five (2.7%) patients, all of whom were operated urgently, died after surgery. Postoperative complications correlated significantly to poor ASA class (p = 0.01), urgency of the procedure (p = 0.03), and extent (p = 0.02) and duration (p = 0.01) of surgery. No significant correlation was found between outcome and any other pre- or intraoperative factors.

CONCLUSIONS

Elderly surgical patients with poor ASA class or following urgent, extensive or long surgery are at a higher risk for postoperative morbidity and mortality, mandating special perioperative care.

Maxillofacial trauma patient: coping with the difficult airway

Establishing a secure airway in a trauma patient is one of the primary essentials of treatment. Any flaw in airway management may lead to grave morbidity and mortality. Maxillofacial trauma presents a complex problem with regard to the patient's airway. By definition, the injury compromises the patient's airway and it is, therefore, must be protected. In most cases, the patient undergoes surgery for maxillofacial trauma or for other, more severe, life-threatening injuries, and securing the airway is the first step in the introduction of general anaesthesia. In such patients, we anticipate difficult endotracheal intubation and, often, also difficult mask ventilation. In addition, the patient is usually regarded as having a "full stomach" and has not been cleared of a C-spine injury, which may complicate airway management furthermore. The time available to accomplish the task is short and the patient's condition may deteriorate rapidly. Both decision-making and performance are impaired in such circumstances. In this review, we discuss the complexity of the situation and present a treatment approach.

[Surgical management of esophageal pathology: 6 years of experience in a single surgical department]

BACKGROUND

Esophageal diseases vary in relation to geographic and behavioral factors. Whether benign or malignant, these diseases interfere with food swallowing. Surgical treatment is variable and aims at restoring the alimentary tract continuity. In this research the authors retrospectively studied esophageal pathologies and their surgical treatment in their department over a 6 year period.

PATIENTS AND METHODS

The records of all patients who underwent surgery for esophageal pathology in a single surgical department at a referral center between January 2002 and December 2007 were reviewed. Data that was collected included patient age, gender, type of pathology, staging, type and length of surgery, length of hospital stay, post-operative morbidity and mortality.

RESULTS

During the study period, 186 patients were operated for esophageal pathology, 154 (83%) had malignant disease and 32 (17%) had benign disease. The distribution of malignancy types was: adenocarcinoma 57%, squamous cell carcinoma 27%, signet ring cell carcinoma 8%, and other 8%. Median length of post-operative hospital stay was 27 days. Thirty two percent of the patients experienced complications, including anastomotic leak (10%), respiratory (9.5%) or cardiac (2%) complications, and infection (7.5%), while 3% required re-operation. Postoperative mortality rate in the hospital was 6.5%.

CONCLUSIONS

The majority of patients undergoing esophageal surgery suffer malignancy, mainly adenocarcinoma. The surgery is extensive and is followed by a long recovery period, during which the patient is subject to a variety of complications. Mortality rate is significant yet comparable to centers around the world with high volume of esophageal operations.

Posterior reversible encephalopathy syndrome after combined general and spinal anesthesia with intrathecal morphine

We describe a patient who was in a stupor for several days after combined general-spinal anesthesia. Both clinical manifestations and magnetic resonance imaging findings were consistent with posterior reversible encephalopathy syndrome and resolved after the patient recovered spontaneously.

Perioperative morbidity and mortality in 80 years and older undergoing elective urology surgery - a prospective study

BACKGROUND AND PURPOSE

The number of octogenarians requiring surgery increases constantly. Data regarding perioperative morbidity and mortality in octogenarians is limited. Our aim was to assess surgery-related complications in octogenarians, undergoing urological surgery.

PATIENTS AND METHODS

We prospectively collected data from octogenarians and a control group of younger patients undergoing an elective urological surgery in our institution. Recorded data included: age, gender, American Society of Anesthesiologists (ASA) score, co-morbidities, number of medications, operation extent, anaesthesia type, surgery duration and perioperative morbidity and mortality.

RESULTS

Forty-seven octogenarians and 80 patients with a median age of 59 years (range 19-75) enrolled prospectively. Gender ratio, surgeries extent and median operative time were similar among groups. General anaesthesia was more prevalent in the control group. ASA classification and duration of hospitalization were significantly higher in octogenarians. The rate of intra-operative complications was significantly higher in the octogenarians group 6.38% versus 3.75% (p = 0.007), there was no significant difference in immediate post-operative and post-discharge complications among groups. One octogenarian patient died 2 days post-surgery, no death occurred in the control group.

CONCLUSIONS

Octogenarians have higher rate of intra-operative morbidity, leading to longer hospital stay. More experienced surgeons and anaesthetists should be involved in the operation; and careful surgical technique, tapered anaesthesia and higher level of post-operative monitoring should be applied for patients in this age.

Cerebral microemboli during hip fracture fixation: a prospective study

BACKGROUND

Recent studies have shown that cerebral fat microembolism takes place during surgery for hip or knee replacement. In this study, we examined the occurrence of cerebral microembolism, solid or gas, during a standard procedure of hip fracture fixation.

METHODS

This was a prospective study of patients who underwent urgent surgery with a dynamic hip screw for hip fracture fixation. During surgery, patients were monitored with transcranial Doppler for detection of microemboli from right and left middle cerebral arteries.

RESULTS

Twenty-two patients were included in the study; their median age was 82 yr (range, 51-97 yr). In nine (41%) patients, high intensity transient signals were recorded, indicating microemboli passage in the middle cerebral arteries. All nine patients had signals of both solid and gas emboli. One of these nine patients had a postoperative cerebrovascular accident.

CONCLUSIONS

The incidence of cerebral microemboli during urgent surgery for hip fracture fixation is considerable. This phenomenon is not confined to hip or knee replacement surgery. The clinical implications of this finding require further investigation.

IgTree: creating Immunoglobulin variable region gene lineage trees

Lineage trees describe the microevolution of cells within an organism. They have been useful in the study of B cell affinity maturation, which is based on somatic hypermutation of immunoglobulin genes in germinal centers and selection of the resulting mutants. Our aim was to create and implement an algorithm that can generate lineage trees from immunoglobulin variable region gene sequences. The IgTree program implements the algorithm we developed, and generates lineage trees. Original sequences found in experiments are assigned to either leaves or internal nodes of the tree. Each tree node represents a single mutation separating the sequences. The mutations that separate the sequences from each other can be point mutations, deletions or insertions. The program can deal with gaps and find potential reversion mutations. The program also enumerates mutation frequencies and sequence motifs around each mutation, on a per-tree basis. The algorithm has proven useful in several studies of immunoglobulin variable region gene mutations.

Antigen-driven selection in germinal centers as reflected by the shape characteristics of immunoglobulin gene lineage trees: a large-scale simulation study

During the immune response, the generation of memory B lymphocytes in germinal centers involves affinity maturation of the cells' antigen receptors, based on somatic hypermutation of receptor genes and antigen-driven selection of the resulting mutants. Affinity maturation is vital for immune protection, and is the basis of humoral immune learning and memory. Lineage trees of somatically hypermutated immunoglobulin genes often serve to qualitatively illustrate claims concerning the dynamics of affinity maturation in germinal centers. Here, we derive the quantitative relationships between parameters characterizing affinity maturation dynamics (proliferation, differentiation and mutation rates, initial affinity of the Ig to the antigen, and selection thresholds) and the mathematical properties of lineage trees, using a computer simulation which combines mathematical models for all mature B cell populations, stochastic models of hypermutation and selection, lineage tree generation and measurement of graphical tree characteristics. We identified seven key lineage tree properties, and found correlations of these with initial clone affinity and with the selection threshold. These two parameters were found to be the main factors affecting lineage tree shapes in both primary and secondary response trees. The results also confirm that recycling from centrocytes back to centroblasts is highly likely.

The biological basis of the bone-muscle inter-relationship in the algorithm of fracture healing

The biological cascade of fracture healing is intimately linked to the muscle envelope. It further depends on the preservation of stable, perpetual axial micromovements. The current study was designed to demonstrate that high molecular weight bioactive substances diffuse from the muscle envelope to initiate osteoinductive activity at experimental fracture sites. Forty-eight rats underwent an experimental fracture of the left tibia and stabilization with an intramedullary 20-gauge needle. The animals were divided into 4 groups (A-D) of 12 rats each according to the post-fracture treatment. In group A (control) no additional treatment was applied following fracture and intramedullary fixation. In groups B, C, and D, a nitrocellulose membrane of various sizes was wrapped around the fracture, separating the periosteum from the muscle envelope. The groups differed by the membrane pore size, allowing passage of the following molecular sizes: 50 kilodaltons (kDa), 12 to 14 kDa, and 3.5 kDa in groups B, C, and D, respectively. Four animals in each group were sacrificed 2, 5, and 10 weeks after the procedure for radiographic and histological evaluation of fracture healing. Radiographic evaluation revealed a decreased rate of bone synthesis that correlated with the nitrocellulose pore size. Morphological and functional analysis of the bone explants indicated poorly healed fractures in groups B, C, and D. Direct contact between fractured bone and its muscle envelope is essential for the biological sequence of new bone formation. The extent of obstruction between the fracture and its muscle envelope correlates with the delay in fracture healing.

A comparison of the Truview blade with the Macintosh blade in adult patients

The Truview blade facilitates a view of the vocal cords by indirect laryngoscopy. We prospectively compared the view obtained at laryngoscopy and intubating conditions of Truview (Group 1) or Macintosh (Group 2) blades in 170 patients who were scheduled to undergo general anaesthesia. We studied pre-operative airway evaluation, laryngoscopic view, duration of intubation, maximal force applied during intubation, anaesthetist's estimation of intubation effort on a 1-3 scale, bleeding, teeth and soft tissue damage, and postoperative stridor and hoarseness. The results demonstrated that, whilst the Truview produced a better laryngoscopic view and less maximal force applied during intubation, the duration of intubation was longer. No significant difference was found in the anaesthetist's estimation of intubation effort, tooth damage or postoperative stridor and hoarseness. Significantly fewer patients suffered bleeding and soft tissue damage following intubation with the Truview than with the Macintosh blade. The Truview blade is a useful option for tracheal intubation in patients with normal and anticipated difficult airways.

Low-Volume Interscalene Brachial Plexus Block for Post-Thoracotomy Shoulder Pain

OBJECTIVES

This study was designed to evaluate the effectiveness of low-volume interscalene brachial plexus block for post-thoracotomy ipsilateral shoulder pain and to compare it with nonsteroidal anti-inflammatory drug treatment.

DESIGN

Prospective nonblinded study.

SETTING

University hospital.

PARTICIPANTS

Sixty adult patients.

INTERVENTION

Patients who underwent elective thoracic surgery under combined epidural and general anesthesia, and after surgery were free of incisional pain but complaining of shoulder pain, were included in the study. They were selected in a sequential manner and placed into 2 groups of 30 patients each. Group 1 had a low-volume interscalene brachial plexus block, using 10 mL of bupivacaine 0.5%. Group 2 had an intramuscular injection of diclofenac sodium, 75 mg.

MEASUREMENTS AND MAIN RESULTS

Pain was measured during their stay in the postanesthesia care unit (PACU) by using a visual analog score (VAS). Opioids were administered when pain relief was incomplete. Pain intensity was re-estimated the next morning and patient satisfaction was scored. VAS was found to be significantly lower in the low-volume interscalene block group than in the diclofenac group at 30 minutes after treatment and when leaving PACU (p < 0.001 for both). Patients in the interscalene block group stayed longer in the PACU (p = 0.019), and significantly fewer required rescue opioids (p = 0.03). There was no significant difference between the groups in patient satisfaction with the pain treatment.

CONCLUSIONS

The authors concluded that low-volume interscalene brachial plexus block is a superior treatment for post-thoracotomy shoulder pain compared with diclofenac injection, although it requires a slightly longer stay in the PACU.

The pyruvate kinase isoenzyme M2 (Tu M2-PK) as a tumour marker for renal cell carcinoma

The M2 isoenzyme of pyruvate kinase (M2-PK) is specially expressed by tumour cells (Tu M2-PK) and has been detected in the peripheral blood of patients with renal cell carcinoma (RCC). We analysed the benefit of using Tu M2-PK as a tumour marker for primary detection of RCC by receiver operating characteristic (ROC) analysis. The area under the curve was 0.674, and the sensitivity, specificity and positive predictive value (PPV) were 44.4%, 87.5% and 88%, respectively, at the ROC optimal cut-off of 28.2 kU/L. We examined 71 patients. Since the marker sensitivity for detection of the early stages T1 and T2 was only 47% it is not suggested to use this marker for primary diagnosis of RCC. Its use as part of the confirmatory preoperative evaluation might be considered in view of its high PPV.