Systematic review: hand activity and ultrasound of the median nerve.

BACKGROUND: Ultrasound is an established method of viewing the median nerve in the carpal tunnel syndrome (CTS). There is some evidence to suggest that immediate changes may occur in the median nerve before and after hand activity. The evidence for the validity and reliability of ultrasound for testing acute changes in the median nerve has not been systematically reviewed to date. AIMS: To evaluate the evidence for visible change in ultrasound appearance of the median nerve after hand activity. METHODS: A literature search was designed, and three reviewers independently selected published research for inclusion. Two reviewers independently appraised papers using the Evidence Based Library and Information Practice (EBLIP) appraisal checklist, while the third reviewer resolved discrepancies between appraisals. RESULTS: Ten studies were appraised and the results showed an increase in median nerve cross-sectional area following activity, with a return to normal size within 1 h following activity. Both healthy individuals and those diagnosed with CTS participated, all were small convenience samples. Ultrasonographic measurements of the median nerve were reliable in the four studies reporting this, and the studies demonstrated high quality. CONCLUSIONS: Good-quality evidence as identified by the EBLIP appraisal checklist suggests that following hand activity, the median nerve changes in size in the carpal tunnel. The results may not be generalizable to all people and activities due to the use of small convenience sampling and narrow range of activities studied, in all of the studies appraised.

Tumour expression of leptin is associated with chemotherapy resistance and therapy-independent prognosis in gastro-oesophageal adenocarcinomas.

BACKGROUND: Cytotoxic chemotherapy remains the main systemic therapy for gastro-oesophageal adenocarcinoma, but resistance to chemotherapy is common, resulting in ineffective and often toxic treatment for patients. Predictive biomarkers for chemotherapy response would increase the probability of successful therapy, but none are currently recommended for clinical use. We used global gene expression profiling of tumour biopsies to identify novel predictive biomarkers for cytotoxic chemotherapy. METHODS: Tumour biopsies from patients (n=14) with TNM stage IB-IV gastro-oesophageal adenocarcinomas receiving platinum-based combination chemotherapy were used as a discovery cohort and profiled with Affymetrix ST1.0 Exon Genechips. An independent cohort of patients (n=154) treated with surgery with or without neoadjuvant platinum combination chemotherapy and gastric adenocarcinoma cell lines (n=22) were used for qualification of gene expression profiling results by immunohistochemistry. A cisplatin-resistant gastric cancer cell line, AGS Cis5, and the oesophageal adenocarcinoma cell line, OE33, were used for in vitro validation investigations. RESULTS: We identified 520 genes with differential expression (Mann-Whitney U, P<0.020) between radiological responding and nonresponding patients. Gene enrichment analysis (DAVID v6.7) was used on this list of 520 genes to identify pathways associated with response and identified the adipocytokine signalling pathway, with higher leptin mRNA associated with lack of radiological response (P=0.011). Similarly, in the independent cohort (n=154), higher leptin protein expression by immunohistochemistry in the tumour cells was associated with lack of histopathological response (P=0.007). Higher leptin protein expression by immunohistochemistry was also associated with improved survival in the absence of neoadjuvant chemotherapy, and patients with low leptin protein-expressing tumours had improved survival when treated by neoadjuvant chemotherapy (P for interaction=0.038). In the gastric adenocarcinoma cell lines, higher leptin protein expression was associated with resistance to cisplatin (P=0.008), but not to oxaliplatin (P=0.988) or 5fluorouracil (P=0.636). The leptin receptor antagonist SHLA increased the sensitivity of AGS Cis5 and OE33 cell lines to cisplatin. CONCLUSIONS: In gastro-oesophageal adenocarcinomas, tumour leptin expression is associated with chemoresistance but a better therapy-independent prognosis. Tumour leptin expression determined by immunohistochemistry has potential utility as a predictive marker of resistance to cytotoxic chemotherapy, and a prognostic marker independent of therapy in gastro-oesophageal adenocarcinoma. Leptin antagonists have been developed for clinical use and leptin and its associated pathways may also provide much needed novel therapeutic targets for gastro-oesophageal adenocarcinoma.

Pharmacokinetic and pharmacodynamic characterization of an oral lysophosphatidic acid type 1 receptor-selective antagonist.

Lysophosphatidic acid (LPA) is a bioactive phospholipid that signals through a family of at least six G protein-coupled receptors designated LPA1₋6. LPA type 1 receptor (LPA1) exhibits widespread tissue distribution and regulates a variety of physiological and pathological cellular functions. Here, we evaluated the in vitro pharmacology, pharmacokinetic, and pharmacodynamic properties of the LPA1-selective antagonist AM095 (sodium, {4'-[3-methyl-4-((R)-1-phenyl-ethoxycarbonylamino)-isoxazol-5-yl]-biphenyl-4-yl}-acetate) and assessed the effects of AM095 in rodent models of lung and kidney fibrosis and dermal wound healing. In vitro, AM095 was a potent LPA1 receptor antagonist because it inhibited GTPγS binding to Chinese hamster ovary (CHO) cell membranes overexpressing recombinant human or mouse LPA1 with IC50 values of 0.98 and 0.73 µM, respectively, and exhibited no LPA1 agonism. In functional assays, AM095 inhibited LPA-driven chemotaxis of CHO cells overexpressing mouse LPA1 (IC50= 778 nM) and human A2058 melanoma cells (IC50 = 233 nM). In vivo, we demonstrated that AM095: 1) had high oral bioavailability and a moderate half-life and was well tolerated at the doses tested in rats and dogs after oral and intravenous dosing, 2) dose-dependently reduced LPA-stimulated histamine release, 3) attenuated bleomycin-induced increases in collagen, protein, and inflammatory cell infiltration in bronchalveolar lavage fluid, and 4) decreased kidney fibrosis in a mouse unilateral ureteral obstruction model. Despite its antifibrotic activity, AM095 had no effect on normal wound healing after incisional and excisional wounding in rats. These data demonstrate that AM095 is an LPA1 receptor antagonist with good oral exposure and antifibrotic activity in rodent models.

Early thymocyte development is regulated by modulation of E2A protein activity.

The E2A gene encodes the E47 and E12 basic helix-loop-helix (bHLH) transcription factors. T cell development in E2A-deficient mice is partially arrested before lineage commitment. Here we demonstrate that E47 expression becomes uniformly high at the point at which thymocytes begin to commit towards the T cell lineage. E47 protein levels remain high until the double positive developmental stage, at which point they drop to relatively moderate levels, and are further downregulated upon transition to the single positive stage. However, stimuli that mimic pre-T cell receptor (TCR) signaling in committed T cell precursors inhibit E47 DNA-binding activity and induce the bHLH inhibitor Id3 through a mitogen-activated protein kinase kinase-dependent pathway. Consistent with these observations, a deficiency in E2A proteins completely abrogates the developmental block observed in mice with defects in TCR rearrangement. Thus E2A proteins are necessary for both initiating T cell differentiation and inhibiting development in the absence of pre-TCR expression. Mechanistically, these data link pre-TCR mediated signaling and E2A downstream target genes into a common pathway.

Thymocyte maturation is regulated by the activity of the helix-loop-helix protein, E47.

The E2A proteins, E12 and E47, are required for progression through multiple developmental pathways, including early B and T lymphopoiesis. Here, we provide in vitro and in vivo evidence demonstrating that E47 activity regulates double-positive thymocyte maturation. In the absence of E47 activity, positive selection of both major histocompatibility complex (MHC) class I- and class II-restricted T cell receptors (TCRs) is perturbed. Additionally, development of CD8 lineage T cells in an MHC class I-restricted TCR transgenic background is sensitive to the dosage of E47. Mice deficient for E47 display an increase in production of mature CD4 and CD8 lineage T cells. Furthermore, ectopic expression of an E2A inhibitor helix-loop-helix protein, Id3, promotes the in vitro differentiation of an immature T cell line. These results demonstrate that E2A functions as a regulator of thymocyte positive selection.

Positive and negative regulation of V(D)J recombination by the E2A proteins.

A key feature of B and T lymphocyte development is the generation of antigen receptors through the rearrangement and assembly of the germline variable (V), diversity (D), and joining (J) gene segments. However, the mechanisms responsible for regulating developmentally ordered gene rearrangements are largely unknown. Here we show that the E2A gene products are essential for the proper coordinated temporal regulation of V(D)J rearrangements within the T cell receptor (TCR) gamma and delta loci. Specifically, we show that E2A is required during adult thymocyte development to inhibit rearrangements to the gamma and delta V regions that normally recombine almost exclusively during fetal thymocyte development. The continued rearrangement of the fetal Vgamma3 gene segment in E2A-deficient adult thymocytes correlates with increased levels of Vgamma3 germline transcripts and increased levels of double-stranded DNA breaks at the recombination signal sequence bordering Vgamma3. Additionally, rearrangements to a number of Vgamma and Vdelta gene segments used predominantly during adult development are significantly reduced in E2A-deficient thymocytes. Interestingly, at distinct stages of T lineage development, both the increased and decreased rearrangement of particular Vdelta gene segments is highly sensitive to the dosage of the E2A gene products, suggesting that the concentration of the E2A proteins is rate limiting for the recombination reaction involving these Vdelta regions.

Morphine: single-dose tolerance.

Rats show a significant degree of tolerance to a second dose of morphine, with the degree of tolerance increasing the longer the delay between the two doses of morphine. To measure the morphine effect a foot-shock attenuation procedure that allowed the animal to adjust the shock intensity was used in studying delays of up to 180 days.

E2A and E2-2 are subunits of B-cell-specific E2-box DNA-binding proteins.

A class of helix-loop-helix (HLH) proteins, including E2A (E12 and E47), E2-2, and HEB, that bind in vitro to DNA sequences present in the immunoglobulin (Ig) enhancers has recently been identified. E12, E47, E2-2, and HEB are each present in B cells. The presence of many different HLH proteins raises the question of which of the HLH proteins actually binds the Ig enhancer elements in B cells. Using monoclonal antibodies specific for both E2A and E2-2, we show that both E2-2 and E2A polypeptides are present in B-cell-specific Ig enhancer-binding complexes. E2-box-binding complexes in pre-B cells contain both E2-2 and E2A HLH subunits, whereas in mature B cells only E2A gene products are present. We show that the difference in E2-box-binding complexes in pre-B and mature B cells may be caused by differential expression of E2A and E2-2.

E2A deficiency leads to abnormalities in alphabeta T-cell development and to rapid development of T-cell lymphomas.

The E2A gene products, E12 and E47, are critical for proper early B-cell development and commitment to the B-cell lineage. Here we reveal a new role for E2A in T-lymphocyte development. Loss of E2A activity results in a partial block at the earliest stage of T-lineage development. This early T-cell phenotype precedes the development of a T-cell lymphoma which occurs between 3 and 9 months of age. The thymomas are monoclonal and highly malignant and display a cell surface phenotype similar to that of immature thymocytes. In addition, the thymomas generally express high levels of c-myc. As assayed by comparative genomic hybridization, each of the tumor populations analyzed showed a nonrandom gain of chromosome 15, which contains the c-myc gene. Taken together, the data suggest that the E2A gene products play a role early in thymocyte development that is similar to their function in B-lineage determination. Furthermore, the lack of E2A results in development of T-cell malignancies, and we propose that E2A inactivation is a common feature of a wide variety of human T-cell proliferative disorders, including those involving the E2A heterodimeric partners tal-1 and lyl-1.

Distal biceps tendon anatomy: a cadaveric study.

BACKGROUND: The anatomy of the distal biceps tendon and aponeurosis has not been studied in detail. METHODS: Seventeen cadaver elbows were dissected with loupe magnification to identify the details of the distal biceps tendon and the lacertus fibrosus. RESULTS: In ten of the seventeen specimens, the distal biceps tendon was in two distinct parts, each a continuation of the long and short heads of the muscle. The remaining seven specimens showed interdigitation of the muscle distally. The tendon continued from each muscle belly. The short head inserted distal to the radial tuberosity and was positioned to be a more powerful flexor of the elbow, while the tendon of the long head inserted on the tuberosity further from the axis of rotation of the forearm and was positioned to be a stronger supinator. The bicipital aponeurosis consisted of three layers and completely encircled the ulnar forearm flexor muscles. The aponeurosis may be important in stabilizing the tendons distally. CONCLUSIONS: The double tendon insertion may allow an element of independent function of each portion of the biceps, and, during repair of an avulsion, the surgeon should ensure correct orientation of both tendon components.

Retro-recombination screening of a mouse embryonic stem cell genomic library.

Targeted gene disruption is an important tool in molecular medicine, allowing for the generation of animal models of human disease. Conventional methods of targeting vector (TV) construction are difficult and represent a rate limiting step in any targeting experiment. We previously demonstrated that bacteriophage are capable of acting as TVs directly, obviating the requirement for 'rolling out' plasmids from primary phage clones and thus eliminating an additional, time consuming step. We have also developed methods which facilitate the construction of TVs using recombination. In this approach, modification cassettes and point mutations are shuttled to specific sites in phage TVs using phage-plasmid recombination. Here, we report a further improvement in TV generation using a recombination screening-based approach deemed 'retro-recombination screening' (RRS). We demonstrate that phage vectors containing specific genomic clones can be genetically isolated from a lambdaTK embryonic stem cell genomic library using a cycle of integrative recombination and condensation. By introducing the gam gene of bacteriophage lambda into the probe plasmid it is possible to select for positive clones which have excised the plasmid, thus returning to their native conformation following purification from the library. Rapid clone isolation using the RRS protocol provides another method by which the time required for TV construction may be further reduced.

Cemented or cementless humeral fixation in reverse total shoulder arthroplasty? a systematic review.

AIMS: To date, there is insufficient evidence available to compare the outcome of cemented and uncemented fixation of the humeral stem in reverse shoulder arthroplasty (RSA). METHODS: A systemic review comprising 41 clinical studies was performed to compare the functional outcome and rate of complications of cemented and uncemented stems in RSA. These included 1455 cemented and 329 uncemented shoulders. The clinical characteristics of the two groups were similar. Variables were compared using pooled frequency-weighted means and relative risk ratios (RR). RESULTS: Uncemented stems had a significantly higher incidence of early humeral stem migration (p < 0.001, RR 18.1, 95% confidence interval (CI) 5.0 to 65.2) and non-progressive radiolucent lines (p < 0.001, RR 2.4, 95% CI 1.7 to 3.4), but a significantly lower incidence of post-operative fractures of the acromion compared with cemented stems (p = 0.004, RR 14.3, 95% CI 0.9 to 232.8). There was no difference in the risk of stem loosening or revision between the groups. The cemented stems had a greater relative risk of infection (RR 3.3, 95% CI 0.8 to 13.7), nerve injury (RR 5.7, 95% CI 0.7 to 41.5) and thromboembolism (RR 3.9, 95% CI 0.2 to 66.6). The functional outcome and range of movement were equivalent in the two groups. DISCUSSION: RSA performed with an uncemented stem gives them equivalent functional outcome and a better complication profile than with a cemented stem. The natural history and clinical relevance of early stem migration and radiolucent lines found with uncemented stems requires further long-term study. TAKE HOME MESSAGE: This study demonstrates that uncemented stems have at least equivalent clinical and radiographic outcomes compared with cemented stems when used for reverse total shoulder arthroplasty.

Management of Mason type-III radial head fractures with a titanium prosthesis, ligament repair, and early mobilization. Surgical technique.

BACKGROUND: Radial head fractures often occur in association with other elbow fractures and soft-tissue injuries. Radial head replacement is indicated for irreparable radial head fractures associated with elbow instability. The purpose of this study was to analyze the results after treatment of such injuries with a titanium radial head prosthesis, repair of torn collateral ligaments, and early mobilization of the elbow. MATERIALS: Sixteen patients with sixteen Mason type-III radial head fractures and collateral ligament injury were treated with use of a titanium radial head prosthesis over a five-year period at the Royal Adelaide Hospital and Modbury Public Hospital in South Australia. The surgery was performed acutely in ten patients and was delayed an average of thirty-seven days (range, fifteen to seventy-nine days) in six. All patients were followed clinically and radiographically for a mean of 2.8 years (range, 1.2 to 4.3 years). RESULTS: Eight patients had an excellent result; five, a good result; and three, a fair result, according to the Mayo Elbow Performance Score. The three fair results occurred in patients with delayed surgery. The mean flexion contracture was 15 degrees (range, 0 degrees to 42 degrees ), with an average loss of 10 degrees (range, 0 degrees to 25 degrees ) of full flexion compared with that of the contralateral elbow. Both pronation and supination decreased an average of 12 degrees (range, 0 degrees to 45 degrees ) compared with that of the contralateral forearm. CONCLUSIONS: The results of treatment of Mason type-III radial head fractures with a monoblock titanium radial head prosthesis and soft-tissue reconstruction are satisfactory. Early mobilization of the elbow is important for the restoration of elbow range of motion and function.

The functional range of motion of the finger joints.

The purpose of this study was to measure the functional range of motion of the finger joints needed to perform activities of daily living. Using the Sollerman hand grip function test, 20 activities were assessed in ten volunteers. The active and passive range of motion was measured with a computerized electric goniometer. The position of each finger joint was evaluated in the pre-grasp and grasp positions. The functional range of motion was defined as the range required to perform 90% of the activities, utilizing the pre-grasp and grasp measurements. The functional range of motion was 19°-71°, 23°-87°, and 10°-64° at the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints, respectively. This represents 48%, 59%, and 60% of the active motion of these joints, respectively. There was a significant difference in the functional range of motion between the joints of the fingers, with the ulnar digits having greater active and functional range. The functional range of motion is important for directing indications for surgery and rehabilitation, and assessing outcome of treatment.

E2A gene products are not required for insulin gene expression.

Transcripts for E2A gene products, ubiquitous basic helix-loop-helix transactivating proteins, are expressed at high levels in the pancreatic epithelium. E2A proteins have been shown to bind the cognate E box sequence (CANNTG) of the insulin promoter/enhancer. E2A gene products dimerize with cell-specific basic helix-loop-helix proteins and synergize with the homeodomain transcription factor, PDX-1, in insulin gene transactivation. PDX-1 is also required for normal pancreatic development in mice. We investigated whether pancreatic development and insulin production could occur in the absence of E2A gene products by studying mice with a null mutation for the gene. E2A(-/-) mice demonstrated normal formation of pancreatic endocrine and exocrine tissue in histochemical sections as well as positive and distinct immunostaining for insulin and glucagon in islet tissue, signifying development of mature beta- and alpha-cells. Moreover, E2A(-/-) mice displayed no significant difference in blood glucose levels or pancreatic insulin content compared with wild-type littermates. These data show that although E2A gene products probably play an important role in insulin gene expression, pancreatic development and insulin production can proceed in their absence.

Effect of doxorubicin on [omega-I-131]heptadecanoic acid myocardial scintigraphy and echocardiography in dogs.

The effects of serial treatment with doxorubicin on dynamic myocardial scintigraphy with [omega-I-131]heptadecanoic acid (I-131 HA), and on global left-ventricular function determined echocardiographically, were studied in a group of nine mongrel dogs. Total extractable myocardial lipid was compared postmortem between a group of control dogs and doxorubicin-treated dogs. A significant and then progressive fall in global LV function was observed at a cumulative doxorubicin dose of 4 mg/kg. A significant increase in the myocardial t1/2 of the I-131 HA was observed only at a higher cumulative dose, 10 mg/kg. No significant alteration in total extractable myocardial lipids was observed between control dogs and those treated with doxorubicin. Our findings suggest that the changes leading to an alteration of myocardial dynamic imaging with I-131 HA are not the initiating factor in doxorubicin cardiotoxicity.

Expression of the genes coding for glutamic acid decarboxylase in pluripotent cell lines.

The expression of glutamic acid decarboxylase (GAD) is a basic characteristic of a wide array of inhibitory neurons the use gamma-aminobutyric acid as a neurotransmitter. Clonal cell models will be essential for investigating the mechanisms which are responsible for the selective expression of GAD. P19 embryonal carcinoma cells are an important model for the analysis of neuronal gene expression. Depending on culture conditions, undifferentiated cells can be induced to form cells as widely divergent as cardiac muscle-like cells and neuron-like and glial-like cells. P19 cells are amendable to a number of powerful genetic manipulations including transformation with foreign DNA and selection of mutants. In this study we used nuclease protection assays and Northern blot analysis to determine if P19 cells express the GAD1 and GAD2 genes. The results show that uninduced P19 cells express these genes at very low but easily detectable levels. When the cells are induced to differentiate along the neuronal pathway with retinoic acid, the levels of transcripts for both GAD genes rise dramatically. At least some RNA transcripts of both genes from induced cells comigrate with the corresponding mRNA from the brain and thus probably represent processed mRNA. The expression of GAD genes in undifferentiated cultures of embryonal stem (ES) cells was also investigated. These cultures express levels of GAD1 transcripts that are higher than uninduced P19 cells. In contrast, expression of the GAD2 gene was barely detectable. These results indicate that P19 EC cells and ES cells will be useful for the investigation of the mechanisms that regulate the expression of the GAD1 and GAD2 genes.