A feasibility study of on-site teacher training for ambulatory preceptors.
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Ambulatory Care↗
Biomedical subjects
J Jensen
Publications and source records attributed to J Jensen.
[Fractures of the pelvis--a survey of "nonunion" and "malunion" surgical results].
UNLABELLED: Nonunion (NU) and malunion (MU) of the pelvis are conditions of absent and malaligned healing of a previous pelvis fracture causing severe disabling symptoms. Reconstructive surgery of the pelvis is more demanding than treatment of the acute fracture. Ten cases of NU and/or MU of the pelvis were treated. Average time from injury to referral was 33 months. Initial treatment was conservative (seven patients), internal fixation (two patients) or combined internal and external fixation (one patient). Complaints were pain (ten patients), limp (eight patients), leg length difference (five patients) and sitting problems (seven patients). RESULTS: All patients showed radiological union. Nine patients had less or no pain at all. All eight with a preoperative limp showed improvement or no limp after surgery. Two of five still had minor leg length difference. All seven patients with sitting problems claimed relief or complete removal of sitting problems. It is concluded that patients with severe disabling symptoms from NU and/or MU can expect relief of symptoms by late correction of the pelvic deformity.
Adolescent↗
Contraction inhibits insulin-stimulated insulin receptor substrate-1/2-associated phosphoinositide 3-kinase activity, but not protein kinase B activation or glucose uptake, in rat muscle.
The initial stages of insulin-stimulated glucose uptake are thought to involve tyrosine phosphorylation of insulin receptor substrates (IRSs), which recruit and activate phosphoinositide 3-kinase (PI 3-kinase), leading to the activation of protein kinase B (PKB) and other downstream effectors. In contrast, contraction stimulates glucose uptake via a PI 3-kinase-independent mechanism. The combined effects of insulin and contraction on glucose uptake are additive. However, it has been reported that contraction causes a decrease in insulin-stimulated IRS-1-associated PI 3-kinase activity. To investigate this paradox, we have examined the effects of contraction on insulin-stimulated glucose uptake and proximal insulin-signalling events in isolated rat epitrochlearis muscle. Stimulation by insulin or contraction produced a 3-fold increase in glucose uptake, with the effects of simultaneous treatment by insulin and contraction being additive. Wortmannin completely blocked the additive effect of insulin in contracting skeletal muscle, indicating that this is a PI 3-kinase-dependent effect. Insulin-stimulated recruitment of PI 3-kinase to IRS-1 was unaffected by contraction; however, insulin produced no discernible increase in PI 3-kinase activity in IRS-1 or IRS-2 immunocomplexes in contracting skeletal muscle. Consistent with this, contraction inhibited insulin-stimulated p70(S6K) activation. In contrast, insulin-stimulated activation of PKB was unaffected by contraction. Thus, in contracting skeletal muscle, insulin stimulates glucose uptake and activates PKB, but not p70(S6K), by a PI 3-kinase-dependent mechanism that is independent of changes in IRS-1- and IRS-2-associated PI 3-kinase activity.
Androstadienes↗
Interdependence of magnetism and superconductivity in the borocarbide TmNi2B2C
We have discovered a new antiferromagnetic phase in TmNi2B2C by neutron diffraction. The ordering vector is Q(A) = (0.48,0,0) and the phase appears above a critical in-plane magnetic field of 0.9 T. The field was applied in order to test the assumption that the zero-field magnetic structure at Q(F) = (0.094,0.094,0) would change into a c-axis ferromagnet if superconductivity were destroyed. We present theoretical calculations which show that two effects are important: a suppression of the ferromagnetic component of the RKKY exchange interaction in the superconducting phase and a reduction of the superconducting condensation energy due to the periodic modulation of the moments at Q(A).
Journal Article↗
[Quality assurance and maintenance of percutaneous nephrostomy drainage].
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Catheterization↗
CCR5 delta32, matrix metalloproteinase-9 and disease activity in multiple sclerosis.
Chemokines and matrix metalloproteinases (MMPs) appear to be crucial in leukocyte recruitment to the central nervous system in multiple sclerosis (MS). CCR5 delta32, a truncated allele of the CC chemokine receptor CCR5 gene encoding a non-functional receptor, did not confer protection from MS. CCR5 delta32 was, however, associated with a lower risk of recurrent clinical disease activity. High CSF levels of MMP-9 activity were also associated with recurrent disease activity. These results directly link intrathecal inflammation to disease activity in patients with MS, suggesting that treatments targeting CCR5 or treatment with MMP inhibitors may attenuate disease activity in MS.
Adult↗
Microvascular anastomoses performed in rats using a microsurgical telemanipulator.
OBJECTIVE: To determine the feasibility of performing microsurgical procedures with a remote telemanipulator using a rat femoral artery anastomosis model. MATERIALS AND METHODS: A remote telemanipulator system was developed that enabled precision movements to be performed at up to 30x magnification. Ten 1-mm femoral artery anastomoses were performed in rats using the telemanipulator, and results were compared to those from a control group in which the procedure was performed with conventional microsurgical techniques. Study endpoints included anastomosis completion time, short-term patency, and procedural complications. Statistical analysis was performed using Student's t-test. RESULTS: All anastomoses performed by remote telemanipulation and by conventional microsurgery were completed successfully. Anastomosis completion times were 100.0 +/- 18.6 minutes in the telemanipulator group and 38.8 +/- 5.0 minutes using conventional techniques (p < 0.001). Patency in both groups at 5 minutes and at one hour was 100%. No intraoperative complications were encountered. Postmortem ex vivo examination of the excised arterial segment revealed no technical defects in either group. CONCLUSIONS: Complex procedures requiring a high degree of precision and dexterity can be performed using an electromechanical interface specifically designed for micromanipulation. Performance limitations are similar to those previously reported for remote surgical teleoperation, and most likely reflect incompletely characterized restrictions on multi-sensory information.
Anastomosis, Surgical↗
Evidence for the differential regulation of Nkx-6.1 expression in the ventral spinal cord and foregut by Shh-dependent and -independent mechanisms.
The Nkx-6.1 homeodomain transcription factor was previously shown to be expressed in ventral neural progenitor cells and subsequently subsets of unidentified motor neurons during early neural development. In this study, we identify a specific subpopulation of motor neurons, the median half of the lateral motor neuron column (LMCm), that retain a strong expression of Nkx-6.1. In addition, we report novel patterns of Nkx-6.1 expression in several mesenchymal tissues surrounding Sonic hedgehog (Shh)-expressing cells, including ventral spinal meninges, esophageal mesenchyme, and dorsal tracheal mesenchyme. Whereas Shh signaling is required for Nkx-6.1 expression in the ventral neural tube and spinal meninges, an Shh-independent pathway appears to operate in regulating Nkx-6.1 expression in the foregut. The persistent and robust expression of Nkx-6.1 in motor neurons and mesenchymal cells suggests an important role for Nkx-6.1 in controlling cell fate specification and differentiation. genesis 27:6-11, 2000.
Animals↗
Pax4 represses pancreatic glucagon gene expression.
The paired box and homeodomain containing transcription factors Pax4 and Pax6 are known to be essential for development of the pancreatic endocrine cells. In this report we demonstrate that stable expression of Pax4 in a rat glucagon-producing cell line inhibits the endogenously expressed glucagon gene completely. Furthermore, Pax4 represses Pax6 independent transcription of the insulin promoter, suggesting that Pax4 can actively repress transcription in addition to acting by competition with the transcriptional activator Pax6.
Animals↗
Quantitative evaluation of surgical task performance by remote-access endoscopic telemanipulation.
BACKGROUND: The performance limitations inherent in minimally invasive surgery may be overcome by using an interface that provides intuitive orientation for video display and tool manipulation. A prototype remote-access endoscopic telemanipulator was designed to fulfill these requirements and used for a surgical anastomosis task. METHODS: A remote-access telemanipulator system, employing remote center-of-motion geometry, was used to complete distant in vitro tubular anastomoses. The performance of four surgeons using this system was compared with that achieved in completing the same anastomosis task in an open environment using open surgical techniques and in a minimally invasive environment using standard laparoscopic methods. RESULTS: The average performance times for completion of the anastomosis task was 1448 +/- 130 s using the telemanipulator system compared with 2108 +/- 291 s with laparoscopic instruments and 296 +/- 25 s with conventional techniques. Leakage rates from the tubular anastomoses were 5.2 +/- 1.4 ml/s in the telemanipulator group, 6.9 +/- 2.0 ml/s in the laparoscopic group, and 3.2 +/- 0.9 ml/s in the conventional methods group. All experimental subjects were able to complete the assigned task in each experimental condition successfully without complications. CONCLUSIONS: Our results in this pilot study suggest that remote-access endoscopic telemanipulation can execute complex three-dimensional manipulations, and that the intuitive orientation of the surgeon's workstation may contribute to easier task completion.
Anastomosis, Surgical↗
WF10 in xenotransplantation-a potential new approach.
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Animals↗
Effects of the antibiotics oxytetracycline and tylosin on soil fauna.
Antibiotics may enter the terrestrial environment when amending soils with manure. A Note of Guidance on ecological risk assessment of veterinary medicines was issued in January 1998. Hardly any information about ecotoxicological effects of already existing substances are available. This study has tested the effects of two widely used antibiotics, tylosin and oxytetracycline, on three species of soil fauna: Earthworms, springtails and enchytraeids. Neither of the substances had any effect at environmentally relevant concentrations. The lowest observed effect concentration was 3000 mg kg-1 and in many cases no effect was seen even at the highest test concentration of 5000 mg kg-1.
Animals↗
Structure-activity relationships of trout bradykinin ([Arg(0),Trp(5),Leu(8)]-bradykinin).
Trout bradykinin ([Arg(0),Trp(5),Leu(8)]-BK) produces sustained and concentration-dependent contractions of isolated longitudinal smooth muscle from trout stomach, although mammalian BK is without effect. Circular dichroism studies have demonstrated that trout BK, unlike mammalian BK, does not adopt a stable beta-turn conformation, even in the presence of sodium dodecyl sulfate (SDS) or trifluoroethanol. The myotropic actions of a series of analogs in which each amino acid in trout BK was replaced by either alanine or the corresponding D-isomer were investigated. The peptides with Ala(4), D-Pro(3), D-Trp(5), D-Ser(6), and D-Pro(7) substitutions were inactive and did not act as antagonists of trout BK. The analog with [Ala(5)] was a weak partial agonist. The substitution (Arg(0) --> Ala) led to >50-fold decrease in potency but, in contrast to the importance of Phe(8) in both BK and desArg(9)-BK in activating the mammalian B(2) and B(1) receptors respectively, substitutions at Leu(8) in trout BK had only a minor effect on potency. Antagonists to the mammalian B(2) receptor generally contain a D-aromatic amino acid at position 7 of BK but the analog [Arg(0),Trp(5),D-Phe(7),Leu(8)]-BK was a weak agonist at the trout receptor. Similarly, the potent nonpeptide mammalian B(2) receptor antagonist FR173657 was without effect on the action of trout BK. These data suggest the hypothesis that the receptor binding conformation of trout BK is defined by the central region (residues 3-7) of the peptide but is adopted only upon interaction with the receptor. The bioactive conformation is probably stabilized by an ionic interaction between Arg(0) in the peptide and an acidic residue in the receptor.
Alanine↗
A phase II trial of triamcinolone hexacetanide for symptomatic recurrent malignant ascites.
Ascites is a common complication of advanced cancer and frequently requires paracentesis to reduce symptoms of pain, anorexia, and dyspnea. For many patients repeat paracenteses are required at short intervals. We prospectively studied 15 patients with recurrent ascites of malignancy to determine if intraperitoneal triamcinolone hexacetonide, a slowly metabolized corticosteroid, produced objective and symptomatic responses. After biochemical, radiological, and symptom assessment and the establishment of the interval between paracenteses, patients underwent large-volume paracentesis followed by intraperitoneal triamcinolone hexacetonide 10 mg/kg. Patients were followed after treatment for assessment of symptoms and physical signs of ascites. Repeat paracentesis was performed when symptomatic ascites recurred. Symptomatic ascites recurred in 13 of 15 patients, but the interval between paracenteses was extended from 9.5 +/- 1.6 days to 17.5 days (P = 0.0086). Symptom questionnaire scores assessing well-being, nausea, abdominal pain, dyspnea, appetite, appearance, and change in abdominal size on a scale from 0 to 6 averaged 3.2 +/- 0.3 at entry and 2.5 +/- 0.2 at the 2-week assessment (P = 0.026). Self-assessed symptoms, feeling of well-being, abdominal distention, and physical appearance improved significantly. The mean serum cortisol decreased from baseline, suggesting that some systemic corticosteroid absorption occurred. Thirteen of 15 patients have died, with a median survival of 42 days. Potential adverse effects included 1 episode each of transient abdominal pain, bacterial peritonitis, and localized herpes zoster infection. In patients with ascites of malignancy, intraperitoneal triamcinolone hexacetonide appears to postpone the requirement for repeat paracentesis and improve symptoms of malignant ascites.
Adult↗
An ovine model of chronic stable heart failure.
BACKGROUND: Chronic stable large animal models of heart failure are difficult to establish. We report an ovine model of chronic stable heart failure achieved by a technique of repetitive myocardial infarctions (one of the most common causes of cardiac failure) with catheter-based techniques. METHODS AND RESULTS: Ejection fraction (EF) was assessed by echocardiography. A perfusion catheter was positioned in either the left anterior descending or circumflex artery by using standard angioplasty techniques. Myocardial infarction was induced by a Gelfoam embolism via this catheter and was confirmed by electrocardiographic (ECG) changes and new segmental abnormalities. The procedure was repeated at 2 weekly intervals until the EF was less than 40%. Target EF was achieved in 15 animals, with a mean of 3.4 embolizations (range 2 to 8). Baseline EF was 68%, with a mean final EF of 33%. This resulted in a 54% reduction in EF (range 44% to 68%) from baseline values. Two animals developed late symptomatic heart failure and died, whereas EF was stable at 3-month follow-up echocardiography in the remaining animals with no significant spontaneous improvement. CONCLUSION: Chronic stable heart failure can be established in sheep with catheter-based skills and a microembolization technique that causes repetitive myocardial infarctions.
Animals↗
Specific elements of a new hemodynamics display improves the performance of anesthesiologists.
OBJECTIVE: We tested the hypothesis that a monitoring display proposed by Blike et al. improves the performance of anesthesiologists. We measured the performance of anesthesiologists using the new display and compared it to their performance with a traditional display. We studied three different displays on how they affected recognition and differentiation of five etiologies of shock-anaphylaxis, bradycardia, hypovolemia, ischemia and pulmonary embolus. METHODS: The participants monitored heart rate, systemic arterial and pulmonary blood pressure, central venous pressure, and cardiac output during five shock states and five non-shock states. The resulting 10 data sets made up ten decision screens, which we presented randomly on a computer monitor to the subjects in one of three different formats (a Single Sensor Single Indicator (SSSI) Numeric display; an Object display; and an Object Minus Shapes display). Subjects used soft-buttons on a computer touch-screen monitor to: a) advance to the next display; b) differentiate a non-shock state from a shock state; and, c) select the etiology of shock state represented by the display (Figure 4). The internal clock and memory of the computer made the collection of data automatic. RESULTS: The subjects recognized a problem more rapidly with the help of a graphical "pointer on a reference scale" in both Object displays, but their accuracy had not improved in comparison to the SSSI Numeric display. The shape of the Object display improved performance of etiology determination compared to the Object Minus Shapes display and SSSI Numeric display. Testing (10 trials) was completed in less than 45 minutes. CONCLUSIONS: The new display with "emergent features" can improve the diagnostic performance of clinicians.
Anesthesiology↗
HLA DRB1*1501 and intrathecal inflammation in multiple sclerosis.
CD4 T cells are considered to be pivotal in the pathogenesis of multiple sclerosis (MS), and the human leukocyte antigen (HLA) haplotype associated with DRB1*1501 confers susceptibility to MS in patients of Northern European descent. Some previous studies have suggested an association of DRB1*1501 with T- and B-cell reactivity to specific myelin protein peptides, other studies suggested an association with enhanced cytokine production or intrathecal immunoglobulin (Ig) synthesis. In order to further assess the role of DRB1*1501 in the pathogenesis of MS, we studied intrathecal inflammation and T-cell phenotypes in patients with possible onset symptoms or clinically definite MS. Presence of DRB1*1501 was associated with higher levels of cerebrospinal fluid (CSF) inflammation as assessed by IgG synthesis levels and higher levels of matrix metalloproteinase-9 activity. DRB1*1501-positive patients also had a lower percentage of T cells in CSF expressing HLA-DR without co-expressing CD25. These findings suggest that enhanced intrathecal inflammation and an altered T-cell activation status may be of importance in conferring the DRB1*1501-associated susceptibility to MS.
Adult↗
Control of endodermal endocrine development by Hes-1.
Development of endocrine cells in the endoderm involves Atonal and Achaete/Scute-related basic helix-loop-helix (bHLH) proteins. These proteins also serve as neuronal determination and differentiation factors, and are antagonized by the Notch pathway partly acting through Hairy and Enhancer-of-split (HES)-type proteins. Here we show that mice deficient in Hes1 (encoding Hes-1) display severe pancreatic hypoplasia caused by depletion of pancreatic epithelial precursors due to accelerated differentiation of post-mitotic endocrine cells expressing glucagon. Moreover, upregulation of several bHLH components is associated with precocious and excessive differentiation of multiple endocrine cell types in the developing stomach and gut, showing that Hes-1 operates as a general negative regulator of endodermal endocrine differentiation.
Amino Acid Sequence↗