[Compression devices for decongestion therapy : A cross-sectional observational survey of handling, pressure, and comfort]. / Kompressionsmittel für die Entstauungstherapie : Vergleichende Erhebung im Querschnitt zu Handhabung, Anpressdruck und Tragegefühl.

BACKGROUND: If compression bandaging is not performed in a professional manner, the objectives of the therapy may not be achieved and side effects or complications may result. OBJECTIVES: This cross-sectional observational survey examines the handling of the treatment options: short-stretch bandages with padding, multicomponent compression systems, and adaptive compression bandages. PARTICIPANTS AND METHODS: During several training sessions on the topic of compression therapy, 137 participants performed compression bandagings on each other. In this regard, they were asked to achieve a predetermined pressure range (short-stretch bandages: 50-60 mm Hg, multicomponent compression systems: 40-50 mm Hg, adaptive compression bandage: 35-45 mm Hg). To evaluate the efficiency, the time used for application, the achieved pressure value, and the comfort were determined. RESULTS: Of the 302 bandagings (n = 137 participants), 28.4% lay within the given target pressure value range. This included 11.2% of performed short-stretch bandages, 35.2% of multicomponent compression systems, and 85.0% of adaptive compression bandages. Significant differences in the mean deviations are found between the treatment options. The bandage was described as being comfortable by 37.7% of users of short-stretch bandages with padding, by 65.0% of those wearing a multicomponent compression system, and by 94.6% of participants with an adaptive compression bandage. CONCLUSIONS: In practice, short-stretch bandages are still the most frequently used care option for the creation of a phlebological compression bandage. In this survey, they proved to be unsafe, time-consuming, and uncomfortable in relation to other treatment options. Multicomponent compression systems and adaptive compression bandages are treatment options that may be a contemporary alternative which also bares more comfort for the patient.

Cost-of-illness of patients with lymphoedema.

BACKGROUND: Chronic lymphoedema is characterized by a continuous need for medical treatment, many comorbidities and impaired quality of life. In Germany, about 4.5 million patients are affected by lymphoedema. Thus, lymphoedema causes high direct and indirect costs, even more in case of complications such as erysipelas and ulcers. OBJECTIVE: The aim of this study was to determine the costs of illness of community lymphoedema patients living in the metropolitan area of Hamburg, Germany. METHODS: An observational cross-sectional study in patients with lymphoedema and combined lipolymphoedema of any origin was performed analysing direct and indirect costs for the patients, the statutory health insurance and society. RESULTS: In total, 348 patients (90.8% female) were examined and interviewed. The mean age of the patients was 57.3 ± 14.5 years. On average, the total costs per patient and year were € 5784, of which € 4445 (76.9%) were direct costs and € 1338 indirect costs. Within the direct medical costs, € 3796 were accounted for the statutory health insurances and € 649 for the patient. The main cost drivers were costs for manual decongestive therapy and disability costs. CONCLUSION: Chronic lymphoedema is associated with high direct and indirect costs. This community-based study is the first cost analysis of chronic lymphoedema and combined lipolymphoedema giving insights to economic impact of lymphoedema treatment. There is a high need for structured disease management programs in order to diagnose and treat lymphoedema early and to avoid complications, thus limiting socio-economic burden.

[Relevance of quality of life as a quality indicator in guideline development]. / Bedeutung der Lebensqualität als Qualitätsindikator in der Leitlinienentwicklung.

BACKGROUND: Guidelines provide systematically developed decision aids for medical treatment. Quality indicators are derived from recommendations of guidelines to promote the implementation of the guideline and to allow for quality management of both the guideline and the health care itself. OBJECTIVES: This study aims to describe the relevance of quality of life as a quality indicator in the development process of guidelines in the German context. METHODS: A systematic literature review was performed in the PubMed database, to highlight the current state of discussion on the use of quality indicators in the development process of guidelines. 90 articles were included in the analysis of the review. RESULTS: The focus of the evaluation of medical guidelines has changed over time. It started with the evaluation of the methodological quality. Currently, the evaluation of the effects of the guide-lines, especially the process quality but also the quality of results, is focused. Many articles merely mentioned that improving the quality of life - as well as reducing morbidity and mortality - is considered as an outcome parameter. Overall, it was obvious that quality of life is not yet considered as a quality indicator in the development of guidelines. CONCLUSIONS: A patient-oriented approach, taking into account the quality of life and not just factors of mortality and morbidity, is increasingly in demand. Therefore, quality of life should be respected in the primary studies underlying the guidelines as well as being a quality indicator.

Thermal tolerance and vulnerability to warming differ between populations of wild Oncorhynchus mykiss near the species' southern range limit.

Fish habitat temperatures are increasing due to human impacts including climate change. For broadly distributed species, thermal tolerance can vary at the population level, making it challenging to predict which populations are most vulnerable to warming. Populations inhabiting warm range boundaries may be more resilient to these changes due to adaptation or acclimatization to warmer temperatures, or they may be more vulnerable as temperatures may already approach their physiological limits. We tested functional and critical thermal tolerance of two populations of wild Oncorhynchus mykiss near the species' southern range limit and, as predicted, found population-specific responses to temperature. Specifically, the population inhabiting the warmer stream, Piru Creek, had higher critical thermal maxima and higher functional thermal tolerance compared to the population from the cooler stream, Arroyo Seco. Arroyo Seco O. mykiss are more likely to experience a limitation of aerobic scope with warming. Piru Creek O. mykiss, however, had higher resting metabolic rates and prolonged exercise recovery, meaning that they could be more vulnerable to warming if prey or dissolved oxygen become limited. Temperature varies widely between streams near the O. mykiss southern range limit and populations will likely have unique responses to warming based on their thermal tolerances and metabolic requirements.

Nonsuppurative encephalitis in a dog.

A 4-year-old male German Hunting Terrier presented with tremor, dyspnea, trismus, spasms of the musculature of the larynx and pharynx, and hypothermia and subsequently died despite intensive clinical care. Prior clinical signs included vomitus and diarrhea. Microscopic examination of the brain revealed a multifocal nonsuppurative brain stem encephalitis; a few intralesional neurons contained intranuclear inclusions. By immunohistochemistry, Aujeszky disease virus (Suid herpesvirus 1) antigen was detected in neurons in the brain and in ganglion cells of the trigeminal ganglia. Viral culture of brain tissue confirmed the presence of Aujeszky disease virus. Histopathologic findings in the brain with the identification of Aujeszky disease virus by immunohistochemistry and polymerase chain reaction are consistent with Aujeszky disease virus-induced encephalitis. Sequencing revealed a 100% homology of the isolated Aujeszky disease virus with Aujeszky disease virus isolates of wild boar from Eastern Germany.

Natural course of small, asymptomatic neuroendocrine pancreatic tumours in multiple endocrine neoplasia type 1: an endoscopic ultrasound imaging study.

Endoscopic ultrasound (EUS) enables detection and localization of pancreatic neuroendocrine tumours. Even small tumours down to a diameter of 1-2 mm can be visualized. Since such small tumours usually cannot be detected by computed tomography (ct), magnetic resonance imaging (mri) and somatostatin receptor scintigraphy (srs), and experience with EUS imaging is limited, there is no clear evidence for clinical management in multiple endocrine neoplasia type 1 (MEN1). Knowledge about the natural course of growth and metastatic distribution is mandatory to come to appropriate clinical decisions and guidelines. This prospective study was aimed to assess the natural course of small (<15 mm) neuroendocrine pancreatic tumours without clinical symptoms due to endocrine activity or mechanical problems and without clear indication for surgical therapy in MEN1 by EUS. A total of 82 asymptomatic tumours<15 mm (5.9+/-3.2 mm diameter at baseline) in 20 patients with MEN1-disease (8 female/12 male, 43+/-13 years) were studied over a period of 20+/-12 months (33.8 patient years, 106.7 tumour years) by EUS. Change in largest diameter of each tumour and annual tumour incidence rate in the patients' cohort were calculated. Increase of largest tumour diameter was found to be 1.3+/-3.2% per month, annual tumour incidence rate 0.62 new tumours per patient year. In one patient, rapid progressive pancreatic manifestation of MEN1 was observed. There was no evidence in ct and/or srs and/or mri for metastatic disease in all patients. Only 4/84 (4.8%) pancreatic tumours could be visualized by computed tomography, 5/79 (6.3%) by somatostatin receptor imaging and 4/39 (10.3%) by magnetic resonance imaging. Small asymptomatic neuroendocrine pancreatic tumours in MEN1 usually seem to grow slowly. Annual tumour incidence rate is low. However, faster growing tumours and patients with rapidly progressive disease can be observed. Risk for obvious metastatic disease from asymptomatic neuroendocrine pancreatic tumours<15 mm in MEN1 seems to be low.

[Orthorad--the online reference database of skeletal plain film radiography]. / Orthorad--die Referenzdatenbank zur Skelettradiographie im Internet.

PURPOSE: It is evident that there is a growing need for Internet-based reference databases for reasons of practicability and due to the increasing use of reporting on digital workstations. The main advantages of online databases are expected with respect to plain film radiography and cross-sectional imaging. A reference database of skeletal plain film radiography was to be created using the Orthorad program. MATERIALS AND METHODS: The most important standard settings and special images of young and healthy adults in plain film radiography were collected over one year. All samples were approved for the Orthorad database by a board qualified radiologist. Based on the workflows of radiographers and radiologists, the records were organized by body part ( http://www.idr.med.uni-erlangen.de/orthorad/orthorad.htm ). This logical data structure will ensure that the tool serves as a source of information in two ways: On the one hand, the radiographer can access information on positioning, tube voltage and cassette format. On the other hand, the radiologist receives important knowledge regarding X-ray anatomy, reference data regarding the human skeleton, and information about the correct reporting for an image. RESULTS AND CONCLUSION: Orthorad is used as an online reference database for traumatologic plain film radiography to support radiographers and radiologists in their daily working routines. To date, user feedback has been positive.

Patient- and person-reports on healthcare: preferences, outcomes, experiences, and satisfaction - an essay.

With the shift towards patient-centered healthcare, patient- and person-reports of health-related factors, including outcomes, are seen as important determinants for evaluating and improving healthcare. However, a comprehensive, systematic categorization of patient- and person-reports is currently lacking in the literature. This study aims at developing a new classification system with well-defined constructs for patients' and persons' self-reports on health and healthcare. A literature research and evaluation by the Reported Health Outcomes (RHO) Group were used to develop this classification system. The new classification system includes patient- and person-reported preferences, outcomes, experiences, and satisfaction related to healthcare and health outcomes. Moreover, the most constitutive methods to measure these four categories - preferences, outcomes, experiences, and satisfaction - have been described in this article. Even though the value of patients' and persons' perspectives on healthcare is increasingly being recognized, its measurement and implementation presents a lasting challenge to researchers, clinicians, patients, and the general population.

The suckling mouse model of cholera.

Vibrio cholerae colonization of the suckling mouse intestine is a commonly used animal model for the human diarrheal disease cholera. This model has a number of advantages as well as disadvantages, and has been extremely useful in the identification and characterization of proven and putative virulence factors involved in human cholera.

Glutamate at the site of phosphorylation of nitrogen-regulatory protein NTRC mimics aspartyl-phosphate and activates the protein.

The NTRC protein of enteric bacteria is an enhancer-binding protein that activates transcription by the sigma 54-holoenzyme form of RNA polymerase under nitrogen-limiting conditions. In vitro NTRC must be phosphorylated to catalyze ATP hydrolysis and activate transcription. The site of phosphorylation of NTRC from Salmonella typhimurium is Aspartate 54, which lies in the amino-terminal regulatory domain of the protein. We used site-directed mutagenesis to make "conservative" substitutions at residue 54 to alanine, asparagine, and glutamate, and examined the properties of the mutant NTRC proteins in vitro and in vivo. In vitro none of them was detectably phosphorylated, as expected if D54 is, in fact, the sole site of phosphorylation. D54A and D54N did not activate transcription of glnA but, interestingly, D54E activated constitutively. Activation by D54E was partial compared to that by phosphorylated wild-type NTRC. Combining D54A or D54N with S160F, a change in the central domain of NTRC that partially bypasses the requirement for phosphorylation, yielded doubly mutant proteins that were as active as a form carrying S160F alone, indicating that the changes in D54 did not adversely affect the function of the remainder of NTRC. Combining D54E with S160F increased the levels of constitutive ATPase activity and transcriptional activation above those of mutant NTRC proteins carrying either single change alone. We conclude that phosphorylation of aspartate 54 is required to activate NTRC and postulate that the D54E mutation mimics phosphorylation, thereby allowing NTRC to hydrolyze ATP and activate transcription. Phenotypes of mutant strains encoding NTRC proteins with substitutions at D54 indicated that phosphorylation of NTRC at position 54 was necessary for normal growth in the absence of glutamine and that such phosphorylation occurred to some extent even in the absence of NTRB.

The major dimerization determinants of the nitrogen regulatory protein NTRC from enteric bacteria lie in its carboxy-terminal domain.

The NTRC protein (nitrogen regulatory protein C) of enteric bacteria is an enhancer-binding protein that activates transcription by the sigma54-holoenzyme form of RNA polymerase. NTRC is a homodimeric protein that binds to a dyad-symmetrical site in DNA. To activate transcription NTRC must be phosphorylated and must form an appropriate oligomeric species at an enhancer. In order to study subunit exchange between NTRC dimers, we constructed a fusion of the maltose-binding protein (MBP) to the amino-terminal end of NTRC (MBP-NTRC) and visualized the formation of heterodimers between MBP-NTRC and wild-type NTRC by a gel-mobility shift assay for DNA-binding. When MBP-NTRC is mixed with wild-type NTRC at 37 degrees C, subunit exchange occurs rapidly. The apparent half-life for dissociation of homodimers of NTRC is two to three minutes at 37 degrees C and is not changed by phosphorylation. The isolated carboxy-terminal domain of NTRC (91 amino acid residues) forms heterodimers with both wild-type NTRC and MBP-NTRC, indicating that the C-terminal domain is sufficient for dimerization. The apparent rate of dissociation of homodimers of the C-terminal domain is essentially the same as that of full-length NTRC, indicating that the major dimerization determinants of the protein lie in its C-terminal domain. Congruent with this, a truncated form of NTRC from which the last 58 amino acid residues were removed is a monomer in solution. Moreover, truncated forms of NTRC from which the last 16 or 26 amino acid residues were removed are predominantly monomeric in solution, as is a mutant form with the amino acid substitution A410E in its C-terminal domain. Monomerization of the above mutant forms of NTRC can be rationalized on the basis of homology between the C-terminal region of NTRC and a 50 amino acid residue region of the factor for inversion stimulation (FIS) protein.

Endosonographic imaging of benign and malignant pheochromocytomas.

Endosonography enables imaging of the adrenal glands, the mediastinum, and the epigastric retroperitoneal area. In this study, the diagnostic power of endosonography regarding the detection and localization of pheochromocytomas and the differentiation between benign and malignant lesions and their metastases and recurrences was investigated. Endosonography was performed using a Pentax FG 32 UA endosonoscope with a longitudinal 7.5-MHz sector array from the esophagus, stomach, and duodenum. A total of 22 pheochromocytomas in 11 patients were studied. All these tumors, recurrences, and metastases were histologically proven except in one single patient where pheochromocytoma had been diagnosed histologically in the past, and actual findings were obvious local recurrence and four metastases. Malignant pheochromocytoma (n = 10) tended to be larger at the time of examination than benign pheochromocytoma (n = 12; P = 0.069). No significant differences between benign and malignant pheochromocytomas regarding echogeneity and echostructure could be detected. However, hyperechoic echogeneity was seen only in benign lesions, which, however, had variable echogeneity. If confirmed by future observations, hyperechoic echogeneity may be considered to be suggestive of a benign nature. In several cases, endosonography detected small lesions that had been missed by routine diagnostic procedures and yielded helpful information for planning surgical strategy. In conclusion, endosonography is considered to be useful in early detection of pheochromocytomas, and in malignant disease of recurrence and metastases.

The use of gadolinium chelates for X-ray digital subtraction angiography.

RATIONALE AND OBJECTIVES: To evaluate the feasibility and safety of using gadolinium chelates for x-ray digital subtraction angiography (DSA) in patients with contraindications to iodinated contrast material. METHODS: We performed 30 DSAs in 22 patients (5 females, 17 males; mean age 64.9 years) with contraindications to iodinated contrast media (renal insufficiency: n = 28; hyperthyroidism: n = 1; contrast allergy: n = 2). Gadolinium chelates were administered as 0.5 mol/L solutions (mean volume of gadolinium chelates per patient was 34 +/- 19 mL). Gadolinium chelates were the sole contrast agent in 17 examinations, were used in conjunction with carbon dioxide (CO2) in 8 studies, (mean 212 +/- 226 mL), and were combined with the restricted use of nonionic iodinated contrast (mean 12.8 +/- 4.7 mL) in 6 examinations. We carried out 15 diagnostic angiographies and 15 percutaneous transluminal angioplasties. RESULTS: Use of gadolinium chelates allowed us to obtain diagnostic angiographic images in all cases. However, the quality of angiograms was inferior compared with that obtained with iodinated contrast agents and superior compared with CO2 as the contrast material. Adverse events were not noted. Mean serum creatinine was 2.6 +/- 1.5 mg/dL before and 2.3 +/- 1.0 mg/dL after DSA. No patient developed contrast-induced nephropathy. CONCLUSIONS: Gadolinium chelates produce an x-ray DSA intermediate in image quality between iodinated contrast and CO2. Digital subtraction angiography with intra-arterial gadolinium chelate administration may offer an alternative to iodinated contrast material in patients with contraindications to iodine.

Vascular response to gadolinium-containing contrast media in an ex vivo rabbit arterial model.

RATIONALE AND OBJECTIVES: To assess the influence of gadolinium-containing magnetic resonance contrast agents on contractility of the arterial vessel wall. METHODS: Bilateral segments of rabbit carotid arteries were mounted in flow chambers, surrounded by aerated (95% O2, 5% CO2) Krebs' solution, and perfused at a constant rate by separated and aerated Krebs' solution. Therefore, changes in pressure of the circulating Krebs' solution indicated alterations of vessel wall contractility. Viability of the artery was tested by 124 mmol/L KCl, 3 x 10-5 mol/L phenylephrine, and 10-5 mol/L acetylcholine. After a washout phase, gadopentate (n = 10) or gadoteridol (n = 10) was added to the perfusate of one carotid artery in increments of 0.1, 0.3, and 0.6 mmol/L. Concentrations up to 0.9 mmol/L and 1.2 mmol/L were tested, respectively. The contralateral artery served as a control. To assess potential relaxing effects of the media, vessels were brought into a contracted status with 3 x 10-5 mol/L phenylephrine and then received gadolinium chelates. RESULTS: Potassium chloride and phenylephrine increased and acetylcholine decreased the pressure, indicating vasoconstriction and vasodilatation, respectively. After gadopentate and gadoteridol infusion, no statistically significant pressure changes could be detected, ruling out any vasoconstrictor or vasodilator effect. CONCLUSIONS: Gadopentetate and gadoteridol in doses of up to 1.2 mmol/L did not alter vessel wall tone. The impact of contrast media on blood pressure, as has been shown in some clinical trials, probably is not due to direct changes in arterial wall tone.

Correlation of flow velocity measurements by magnetic resonance phase contrast imaging and intravascular Doppler ultrasound.

RATIONALE AND OBJECTIVES: The authors compare the magnetic resonance (MR) phase contrast flow velocity measurements in varying concentric stenoses with invasive measurements obtained with a Doppler guidewire. METHODS: Flow velocity measurements were obtained using a calibrated 0.018 inch 12 MHz Doppler guidewire and a 1.0 T MR imaging system in a pulsatile hydraulic model with variable arterial stenoses. Velocity measurements were performed proximal, intrastenotic, and distal to the stenoses. The cross-sectional area of stenosis was calculated from the data of both methods. For MR imaging measurements, fast low-angle shot two-dimensional phase contrast sequences with different velocity encodings were used. RESULTS: Phase contrast flow measurements correlated well (r = 0.95, Pearson) with Doppler guidewire-based flow velocity data. Generally, flow velocities obtained with MR imaging were lower when compared with the Doppler-based data (P < or = 0.001, Wilcoxon matched pairs test). However, the ratios and the calculated cross-sectional area of stenoses showed a high correlation (r = 0.96) with the predefined area of stenoses. CONCLUSIONS: The assessment of flow alterations in vitro due to variable stenoses using MR phase contrast flow measurements is very well correlated with the Doppler guidewire. Consequently, these results required in vivo measurements of atherosclerotic lesions to evaluate the clinical impact.

Pattern recognition system for focal liver lesions using "crisp" and "fuzzy" classifiers.

RATIONALE AND OBJECTIVES: To determine the diagnostic performance of an artificial intelligence system for classification of focal liver lesions, in comparison to human observers. METHODS: One hundred forty-three focal hepatic lesions were evaluated with dynamic computed tomography. The study comprised 59 hemangiomas, 24 other benign lesions (focal nodular hyperplasia, adenoma), and 60 malignant liver lesions (18 primary, 42 secondary). All lesions but the hemangiomas were histologically examined by needle biopsy. For delineation of the lesion, a region of interest was defined interactively. The pattern recognition was performed in two steps with initial extraction of textural features: training of a classifier and classification of the lesions. The accuracy of classification of hepatic lesions into three groups (hemangioma, other benign processes, malignant lesions) was tested. The results were compared with those achieved by human observers using receiver operating characteristic statistical analysis. RESULTS: The accuracy (total rate of correct diagnoses) was 90.2%. False classifications were found owing to small size, weak contrast enhancement after bolus injection, respiratory movement, and atypical morphology of the lesion. The area under the receiver operating characteristic curve was not significantly different for computer and human observers. CONCLUSIONS: The system demonstrated a diagnostic accuracy comparable to human observers. Further improvement with increasing numbers of typical computed tomographic series for training of the classifier can be expected.

Magnetic resonance colonography and virtual magnetic resonance colonoscopy with the 1.0-T system: a feasibility study.

RATIONALE AND OBJECTIVES: An ex vivo study and a clinical, prospective, patient study were undertaken to evaluate the feasibility of magnetic resonance (MR) colonography with a 1.0-T system. METHODS: An ex vivo colon model was scanned. A cleaned pig colon was prepared with six simulated sessile polyps (diameters of 4-12 mm) and one simulated pedunculated polyp (diameter of 5 mm). Subsequently, five patients (aged 39-81 years; four women, one man) were examined with MR colonography, immediately followed by endoscopic colonoscopy. After preparation for colonoscopy, the colon was filled with a Gd-DTPA/water solution (1:100). A breath-hold 3D gradient-echo sequence was acquired in both the prone and supine positions and after intravenous Gd-DTPA administration. Images were analyzed interactively by using multiplanar projections, maximum-intensity projection, and a virtual endoscopic view. The MR results were compared with the findings of the fiberoptic endoscopy. RESULTS: All seven simulated lesions of the colon model could be detected by MR imaging. In one patient, an advanced colon cancer as well as an additional small polyp was depicted. In the other four patients, single polyps with a diameter of 1 to 2.5 cm and a large adenoma were visualized by MR colonography. Contrast enhancement of the polyps was noted only after subtraction. CONCLUSIONS: The 1.0-T system is feasible for MR colonography. Reduced requirements for hardware could contribute to establish the novel technique as a screening method for colorectal polyps.

Distribution and latency of muscle responses to transcranial magnetic stimulation of motor cortex after spinal cord injury in humans.

Noninvasive transcranial magnetic stimulation (TMS) of the motor cortex was used to evoke electromyographic (EMG) responses in persons with spinal cord injury (n = 97) and able-bodied subjects (n = 20, for comparative data). Our goal was to evaluate, for different levels and severity of spinal cord injury, potential differences in the distribution and latency of motor responses in a large sample of muscles affected by the injury. The spinal cord injury (SCI) population was divided into subgroups based upon injury location (cervical, thoracic, and thoracolumbar) and clinical status (motor-complete versus motor-incomplete). Cortical stimuli were delivered while subjects attempted to contract individual muscles, in order to both maximize the probability of a response to TMS and minimize the response latency. Subjects with motor-incomplete injuries to the cervical or thoracic spinal cord were more likely to demonstrate volitional and TMS-evoked contractions in muscles controlling their foot and ankle (i.e., distal lower limb muscles) compared to muscles of the thigh (i.e., proximal lower limb muscles). When TMS did evoke responses in muscles innervated at levels caudal to the spinal cord lesion, response latencies of muscles in the lower limbs were delayed equally for persons with injury to the cervical or thoracic spinal cord, suggesting normal central motor conduction velocity in motor axons caudal to the lesion. In fact, motor response distribution and latencies were essentially indistinguishable for injuries to the cervical or thoracic (at or rostral to T10) levels of the spine. In contrast, motor-incomplete SCI subjects with injuries at the thoracolumbar level showed a higher probability of preserved volitional movements and TMS-evoked contractions in proximal muscles of the lower limb, and absent responses in distal muscles. When responses to TMS were seen in this group, the latencies were not significantly longer than those of able-bodied (AB) subjects, strongly suggestive of "root sparing" as a basis for motor function in subjects with injury at or caudal to the T11 vertebral body. Both the distribution and latency of TMS-evoked responses are consistent with highly focal lesions to the spinal cord in the subjects examined. The pattern of preserved responsiveness predominating in the distal leg muscles is consistent with a greater role of corticospinal tract innervation of these muscles compared to more proximal muscles of the thigh and hip.

Peripheral competition in the control of sensory neuron numbers in Xenopus frogs reared with a single bilaterally innervated hindlimb.

Sensory neurons were counted in the hind-limb innervating spinal ganglia on both sides of juvenile Xenopus frogs which, as tadpoles, had had one hind limb bud amputated prior to innervation, and a channel made to allow innervation of the remaining limb bud from both sides. The total number of sensory neurons surviving on the two sides approximated the number on one side of normal frogs, the ipsilateral and contralateral numbers being negatively correlated. These effects differ markedly from the effects on motoneuron numbers, suggesting different control mechanisms of cell death in the two neuronal classes.

High-resolution diffusion-weighted MR of fresh and fixed cat spinal cords: evaluation of diffusion coefficients and anisotropy.

PURPOSE: To use high-resolution diffusion-weighted and calculated apparent diffusion coefficient (ADC) MR imaging to determine whether fixation and storage influence diffusion anisotropy in white matter tracts of cat spinal cord specimens. METHODS: Four cat cord specimens were imaged using a diffusion-weighted spin-echo sequence. Diffusion encoding was applied in the section-select axis (parallel to white matter tracts) and in the read axis (perpendicular to white matter tracts). Five sets of axial diffusion-weighted images were acquired with b values ranging from 0 to 800 s/mm2 and used to obtain calculated ADC images and to determine diffusion coefficients in different regions of the white matter tracts. RESULTS: After cord fixation, a decrease in T2 relaxation and spin density in the white matter caused the signal intensity to appear similar on diffusion-weighted images when the diffusion-probing gradient was applied along both the section-select and read axes. On the calculated ADC images, however, distinct differences in signal intensities were seen in the section-select and read axes. CONCLUSION: Although there is little difference in signal intensity in the white matter tracts on diffusion-weighted images when diffusion encoding is applied in the section-select or read axis in the fixed specimens, calculated ADC images confirm that diffusion anisotropy is maintained. Therefore, calculated ADC images may be helpful in the evaluation of fixed spinal cord specimens.