Swiss ball enhances lumbar multifidus activity in chronic low back pain.

OBJECTIVES: This study examined the effects of sitting surfaces on the cross-sectional area of lumbar multifidus (LM) in patients with Chronic Low Back Pain (CLBP) and healthy controls (HC). DESIGN: Cross-Sectional Case Controlled Study. SETTING: Isle of Man Institute of Sport. PARTICIPANTS: 40 age and sex matched, sporting participants aged 18-45 years, recruited from private physiotherapy practice patients (n = 20 CLBP, 16 male, 4 female, and n = 20 healthy controls, 16 males and 4 females). MAIN OUTCOME MEASURES: Cross-sectional area of LM was measured using rehabilitative ultrasound imaging. RESULTS: Swiss Ball (SB) was more effective at stimulating LM than a Stable Surface (SS) in both groups: CLBP:SB:12.3 (cm(2)) (SD:3.6), SS:10.15 (SD:2.6), p < 0.0001; HC:SB:12.5 (SD:2.7), SS:11.3 (SD:2.9), p < 0.0001). No significant differences between groups were noted. No differences between left and right side cross-sectional areas between or within groups were noted. CONCLUSION: Cross-sectional area of LM increased as the lability of the surface increased, demonstrating that SB was more effective at stimulating LM activity than a non-labile surface. This confirms current clinical practice and supports the use of a labile surface in spinal rehabilitation. The lack of LM asymmetry within and between groups is discussed.

An investigation of the effects of TETRA RF fields on intracellular calcium in neurones and cardiac myocytes.

PURPOSE: This study aimed to determine whether Terrestrial Trunked Radio (TETRA) fields can affect intracellular calcium signalling in excitable cells. MATERIALS AND METHODS: Intracellular calcium concentration ([Ca(2 +) ](i)) was measured in cultured rat cerebellar granule cells and cardiac myocytes during exposure to TETRA fields (380.8875 MHz pulse modulated at 17.6 Hz, 25% duty cycle). [Ca(2 +) ](i) was measured as fura-PE3, fluo-3 or fluo-4 fluorescence by digital image analysis. RESULTS: Granule cells exposed at specific absorption rates (SARs) of 5, 10, 20, 50 or 400 mW x kg(-1) showed no significant changes in resting [Ca(2 +) ](i). Increases in [Ca(2 +) ](i) in response to potassium-induced depolarization were significantly different from sham controls in TETRA-exposed cells, but the majority of the difference was attributable to initial biological variation between cell cultures. No difference was found between fura-PE3 (UV excitation) and fluo-3 (visible light excitation) measurements in these cells. Exposure to TETRA (50 or 400 mW x kg(-1)) had no significant effect on either the rate or amplitude of spontaneous Ca(2 +) transients in cardiac myocytes. The cells showed normal responses to salbutamol (50 microM) and acetylcholine (10 microM). CONCLUSIONS: Overall, these results showed no evidence of any consistent or biologically relevant effect of TETRA fields on [Ca(2 + )](i) in granule cells and cardiac myocytes at any of the SAR tested.

Effects of low intensity radiofrequency electromagnetic fields on electrical activity in rat hippocampal slices.

Slices of rat hippocampus were exposed to 700 MHz continuous wave radiofrequency (RF) fields (25.2-71.0 V m(-1), 5-15 min exposure) in a stripline waveguide. At low field intensities, the predominant effect on the electrically evoked field potential in CA1 was a potentiation of the amplitude of the population spike by up to 20%, but higher intensity fields could produce either increases or decreases of up to 120 and 80%, respectively, in the amplitude of the population spike. To eliminate the possibility of RF-induced artefacts due to the metal stimulating electrode, the effect of RF exposure on spontaneous epileptiform activity induced in CA3 by 4-aminopyridine (50-100 microM) was investigated. Exposure to RF fields (50.0 V m(-1)) reduced or abolished epileptiform bursting in 36% of slices tested. The maximum field intensity used in these experiments, 71.0 V m(-1), was calculated to produce a specific absorption rate (SAR) of between 0.0016 and 0.0044 W kg(-1) in the slices. Measurements with a Luxtron fibreoptic probe confirmed that there was no detectable temperature change (+/- 0.1 degrees C) during a 15 min exposure to this field intensity. Furthermore, imposed temperature changes of up to 1 degrees C failed to mimic the effects of RF exposure. These results suggest that low-intensity RF fields can modulate the excitability of hippocampal tissue in vitro in the absence of gross thermal effects. The changes in excitability may be consistent with reported behavioural effects of RF fields.

Dry skin, moisturization and corneodesmolysis.

The process leading to the loss of corneocytes form the skin surface is termed desquamation. In healthy skin it is an orderly and essentially invisible process whereby individual or small groups of corneocytes detach from neighbouring cells to be lost to the environment and replaced by younger cells from the deeper layers. Desquamation is carefully controlled to ensure that corneum cohesion and integrity, and hence tissue thickness, is maintained. The most important components of the corneocytes contributing towards intercellular cohesion are the corneodesmosomes and lipids. Corneodesmosomes are proteinaceous complexes which effectively rivet corneocytes together. The intercellular lipids, primarily responsible for the water barrier, also provide part of the extracellular cement. In addition, the shape of the corneocyte itself plays a role in stratum corneum cohesion. Through interdigitation along their peripheral edges, adjacent corneocytes become physically locked together, a process which reinforces the integrity of the tissue. For effective desquamation to occur corneodesmosomes must be degraded: a process catalysed by serine proteases present within the intercellular space and facilitated by subtle changes in lipid composition and phase behaviour. Ultimately, it is the availability of free water which controls corneodesmolysis. In healthy skin this proteolytic process leaves relatively few corneodesmosomes intact in the most superficial layers. By contrast, in chronic and acute dry skin conditions, corneodesmosomal degradation and hence the final stages of desquamation are perturbed, leading to the characteristic formation of visible, powdery flakes on the skin surface. The inability to degrade these structures ultimately reflects a decreased hydrolytic activity of the desquamatory enzymes, either through reduced synthesis of the enzymes, inherent loss of activity, leaching from the surface layers of the corneum or changes in the surrounding lipid-rich microenvironment, which may indirectly reduce enzyme functionality. Increased understanding of the desquamation process is providing new insights into the mode of action of current moisturizing ingredients and is offering opportunities to develop novel therapies for preventing and correcting dry skin.

Low doses of repetitive ultraviolet A induce morphologic changes in human skin.

Repetitive exposure of skin to sunlight is known to result in dermatoheliosis, characterized by photoaging and carcinogenesis. It has been demonstrated previously that relatively large amounts of ultraviolet (UV) A can produce photodamage and it is believed that UVB plays a major role in the induction of photodamage and photocarcinogenesis. The study reported here determines the cutaneous effects of minimal erythemal amounts of solar-simulated UV radiation as well as suberythemal and minimal erythemal doses of UVA. Previously non-sunexposed human skin was irradiated twice weekly for 24 weeks. Biopsies were obtained 12, 24 and 36 weeks after the initial irradiation and assessed for both epidermal and dermal alterations. Dermal elastic tissue content was measured via computerized image analysis. All UV treatment regimens produced observable epidermal and dermal changes. These alterations were observed after only 12 weeks of twice-weekly irradiation and were still evident 12 weeks after the final irradiation. Interestingly, UVA irradiation produced a decrease in elastic tissue content whereas solar-simulated UV produced a slight increase. Most notable were the changes produced by the suberythemal dose of UVA. Surprisingly, this relatively low UVA dose produced a reduction in elastic tissue content. The results of this investigation demonstrate that small amounts of UVA or solar-simulated UV are capable of producing cutaneous photodamage. These findings suggest that even suberythemal doses of repetitive UVA may lead to photoaging of the skin and that there is a need for daily broad spectrum UV protection.

Exchange arthroplasty for infected knee replacements. A new two-stage method.

We report a series of 17 exchange arthroplasties for infected knee prostheses, ten one-stage and seven two-stage procedures. The method proved successful in controlling infection and restoring function. In two-stage exchanges the interval between the stages was managed by using a prosthesis as a spacer, and acrylic cement beads containing the appropriate antibiotic to provide high local concentrations. Three one-stage procedures had recurrence of infection, but were successfully treated by further exchange operations. All patients had satisfactory function and there have been no serious complications. We recommend this modified two-stage technique for the management of infected knee arthroplasties.

Pacemaker electrode repositioning using the loop-snare technique.

Using a percutaneous femoral vein approach under fluoroscopic control, a malpositioned ventricular pacemaker electrode was released from the right ventricular wall by hooking the lead with a deflecting wire inserted into a RIM catheter. A closed loop was formed by tightening the handle of the wire allowing the electrode to be dislodged and pulled into the inferior vena cava. The electrode was then snared using a loop formed by an exchange wire advanced through an 8 French catheter with a J-curve steamed at its tip. The electrode was advanced to the right ventricular apex and released by advancing one end of the snare wire while pulling the other end to open the loop.

The use of intravenous cholangiography in teaching hospitals: a survey.

Thirty academic radiology departments active in biliary imaging were surveyed to document how frequently intravenous cholangiography (IVC) was being performed. Over a 10-year period the number of examinations has decreased precipitously from approximately 1728 in 1976 to 8 in 1986. This coincides with the increased availability of alternative procedures. The availability of new contrast agents with improved diagnostic yield and decreased toxicity suggests that its use may have been prematurely abandoned.

Evidence for filaggrin as a component of the cell envelope of the newborn rat.

A substrate of transglutaminase, specific to the epidermis, was identified, by fluorescent and radioactive labelling with the lysine analogues dansylcadaverine and [14C]putrescine respectively, in newborn-rat epidermal homogenates and whole-skin organ cultures. The labelled analogues were preferentially incorporated into the stratum-corneum protein filaggrin in a Ca2+-dependent manner in both 'in vitro' systems. When filaggrin was labelled in vivo with [3H]histidine and then incubated with rat epidermal preparations, the label was rendered SDS/thiol-insoluble. Incorporation of [3H]filaggrin into the insoluble envelope fraction was Ca2+-dependent and inhibited by EDTA and exogenous amines. Antisera to newborn-rat filaggrin cross-reacted with purified newborn-rat cell envelopes, and this reaction was blocked by adsorbing the antiserum with purified filaggrin. Quantification of the 'envelope-bound' filaggrin showed it to be a significant component, accounting for approx. 10% of the cell-envelope protein.

Ruptured breast implant: computed tomographic and mammographic findings.

We report the computed tomographic and mammographic findings in a patient with a ruptured breast implant. The diagnosis was made by recognition of alteration in prosthesis contour, collapse of the prosthesis envelope, and the presence of free silicone in the breast and axillary region.

Resectable stage III lung cancer: CT, surgical, and pathologic correlation.

The new International Staging System identifies a subset of patients with stage III lung cancer who have improved survival rates after surgical resection. The computed tomographic (CT), surgical, and pathologic findings in 26 patients with completely resected stage IIIa lung cancer were reviewed. Preoperative CT scans accurately demonstrated chest wall invasion in only two of ten patients with chest wall or diaphragmatic invasion. CT demonstrated pericardial involvement in only one of three patients. Tumor extension to within 2 cm of the tracheal carina was seen with CT in one of three patients. Eleven of 26 patients had limited ipsilateral mediastinal (N2) disease; eight of 11 had affected nodes greater then 10 mm on CT scans. As previously shown, CT is of limited value in the assessment of chest wall, mediastinal, pleural, or pericardial tumor extension; however, such extension does not preclude complete resection. Ipsilateral node involvement does not preclude surgery. Familiarity with the new staging system and awareness of what constitutes potentially resectable disease are necessary for an adequate assessment of CT findings.

Alterations in the metabolism of filaggrin in the skin after chemical- and ultraviolet-induced erythema.

We have investigated the effect on the normal synthesis and metabolism of filaggrin of treatment of guinea pig skin with a chemical irritant, hexadecane, or with erythemal doses of UV radiation. Examination of the skin by immunofluorescence with an antiserum against filaggrin demonstrates 3 phases of the response. The first phase is an apparent stabilization of the filaggrin present at the time of treatment. Thus, a zone of stratum corneum is produced which moves up toward the skin surface over the days following treatment, without the loss of immunoreactivity which normally results from the metabolism of filaggrin to free amino acids. The second phase of the reaction, which occurs during the first day after treatment, is a loss of immunoreactive material from the upper viable epidermis, which results over the next day in the formation of a zone of filaggrin-deficient stratum corneum. The third phase, 2-3 days after the treatment, is the reestablishment of immunoreactivity in the newly re-formed granular layer, followed by the formation of an immunoreactive zone at the bottom of the stratum corneum. This zone remains very thin despite the rapid passage of cells through it. This shows that the filaggrin being formed during this phase of the reaction is being broken down normally as the stratum corneum matures. Investigations of the kinetics of filaggrin synthesis and breakdown using a [3H]histidine pulse/chase method, confirm the impression gained from immunofluorescence studies that the time between formation and breakdown of the filaggrin is much reduced in the hyperplastic epidermis resulting from the irritation. Thus, although the hyperplasia is reflected in a thickening of malpighian and granular layers of the epidermis, it does not result in any thickening of the filaggrin-positive zone at the bottom of the stratum corneum. This suggests the action of a control mechanism designed to prevent the extension of this filaggrin-positive zone into the upper stratum corneum.

Filaggrin breakdown to water binding compounds during development of the rat stratum corneum is controlled by the water activity of the environment.

Filaggrin is a specific epidermal protein which is the precursor of the free amino acids, urocanic acid and pyrrolidone carboxylic acid which are largely responsible for the ability of the stratum corneum of the skin to remain hydrated at low environmental humidity. The distribution of filaggrin shown by immunofluorescence in the stratum corneum of the rat changed dramatically during the first hours of postnatal life. During late foetal development, filaggrin accumulated through the entire thickness of the stratum corneum, indicating that there was a block on the subsequent processing of the protein which normally would convert it to free amino acids. Immediately after birth this block was lifted and normal proteolysis of the filaggrin took place in the outer part of the stratum corneum, leaving the normal adult pattern of a thin zone of cells containing filaggrin at the bottom of the stratum corneum. This activation of filaggrin proteolysis was dependent on the drop in external water activity caused by the transition from an aqueous environment in utero to a dryer environment after birth and it could be blocked by maintaining a 100% humidity atmosphere around the newborn rat after birth. In isolated stratum corneum in vitro, filaggrin proteolysis took place only between 80 and 95% relative humidity, both higher and lower relative humidity blocked the proteolysis. Application of occlusive patches to adult rats prevented the normal proteolysis of filaggrin, indicating that this mechanism controls not only the massive filaggrin proteolysis occurring after birth but also the proteolysis occurring during normal stratum corneum maturation. The stratum corneum therefore has the ability to respond to changes in external humidity by altering the level of the stratum corneum where it converts its reserves of filaggrin into water binding amino acids, such that under humid conditions water binding components will be produced in only the most superficial stratum corneum, or even not produced at all.

Late paraplegia as a consequence of intraaortic balloon pump support.

There have been several reports of paraplegia after intraaortic balloon counterpulsation in the surgical literature. In each instance, the paraplegia occurred during the period of counterpulsation support. We describe a patient in whom late paraplegia occurred three days after the removal of an intraaortic balloon catheter.

Markers of epidermal differentiation expressed by rat keratinocytes cultured by a modified feeder layer technique.

A broad range of analytical methods has been used to investigate the expression of key differentiation markers in keratinocytes cultured by a modified feeder layer technique. Cultures were stratified and showed many of the features characteristic of epidermal differentiation in vivo including tonofilaments, desmosomes, loss of organelles and thickening of the plasma membrane to form the cornified envelope. Profilaggrin synthesis was detected by 32P-incorporation and the presence of filaggrin suggested that it was broken down by the normal route. Staining with the lectin from Ulex europeus revealed the presence of a fucose-containing cell-surface glycoprotein. Keratin synthesis was shown by 3H-leucine incorporation and keratins were analysed by two-dimensional gel electrophoresis in comparison with those from different levels of the epidermis. Quantitative and qualitative differences were found between in vivo and in vitro epidermal differentiation. In particular, cornified envelope numbers were low, in keeping with the observation by electron microscopy of only one layer of cells with this structure. The absence of a true stratum corneum in vitro was also indicated by the virtual absence of histidase activity and stratum corneum keratins. The keratin species present in vitro most closely resembled those of the basal cells of the epidermis, although even in this case differences were observed. The evidence as a whole is consistent with the belief that epidermal cells do synthesise in vitro many of the important proteins involved in differentiation, but that they nevertheless do not develop a true keratinised stratum corneum.