Abnormal skin temperature reactions have been reported in type I diabetic patients. Whether this is due to a primary vascular disturbance or autonomic neuropathy is unclear. The aim of this study was to clarify this issue by evaluating cutaneous circulatory reactions before and after provocation. Seventeen type I diabetic patients and 17 age-matched controls were studied by recording blood flow (laser Doppler technique) on the dorsum of the hand (before, during, and after arterial occlusion), blood flow and skin temperatures on the dorsum of the foot and on the toe (before and after cooling followed by indirect body heating) and autonomic nerve function (heart rate reaction to deep breathing and to tilting). The results showed that before [4.6 +/- 0.5 perfusion units (PU) versus 6.1 +/- 0.7 PU; p = 0.0356] and after arterial occlusion (17.5 +/- 1.6 PU versus 25.3 +/- 1.7 PU; p = 0.0024), hand skin blood flow was significantly lower in patients than in controls. On the dorsum of the foot, skin temperatures was significantly lower in patients than in controls before cooling (29.2 degrees C +/- 0.3 degrees C versus 30.5 degrees C +/- 0.4 degrees C; p = 0.0107) whereas toe temperature and toe blood flow were similar before and after cooling in patients and controls. After body heating, however, toe temperature (after 30 min: 25.2 degrees C +/- 1.4 degrees C versus 30.9 degrees C +/- 1.2 degrees C; p = 0.0022) and toe blood flow (after 30 min: 10.9 +/- 2.5 degrees C versus 22.9 +/- 4.9 PU; p = 0.0313) were significantly lower in patients than in controls, especially in patients with parasympathetic neuropathy (i.e., patients with abnormal heart rate reactions to deep breathing). In conclusion, type I diabetic patients demonstrated a vascular disturbance in their skin that seemed to be exaggerated by parasympathetic neuropathy.

Adult↗

PubMedDate not supplied

Quantitative sensory changes in humans after intravenous regional block with mepivacaine.

BACKGROUND AND OBJECTIVES: In previous studies we have demonstrated that after intravenous regional block (IVRA) with dilute mepivacaine, there is a decrease in neurogenic inflammation as well as in post-ischemic hyperemia and steady-state flow, the latter for at least 60 minutes. It is unclear whether these vascular reactions reflect a uniform depression of nerve function in the treated arms. Because the various afferents convey impulses from different types of sensory receptors, we used quantitative sensory testing (QST) to define these effects of IVRA with mepivacaine. METHODS: In 16 volunteers, bilateral blocks were performed by simultaneously injecting mepivacaine in one arm and normal saline in the other in a randomized, double-blind manner. Both arms were kept ischemic for 20 minutes, and the pain was rated on a visual analogue scale. Skin temperature and perception threshold values regarding touch (Abeta-fibers), warmth (C-fibers) and cold (Adelta-fibers), and heat pain (C-fibers) were determined before and repeatedly after the blocks. RESULTS: Ischemic pain did not differ between the arms. After reflow, the thresholds for touch, warmth, and heat pain were unchanged. In the mepivacaine-treated arm, the sensibility to cold was significantly decreased 10 and 30 minutes after the block, though there was a slight decrease in skin temperature. CONCLUSIONS: There was no uniform depression of nerve function after IVRA. The cold receptors and/or their Adelta-fibers were selectively depressed after the block. In conjunction with earlier findings, this suggests that IVRA with mepivacaine can differentially decrease neurogenic inflammation, with little impairment of sensory function.

Adolescent↗

PubMedDate not supplied

A two-year follow-up of work capacity in early rheumatoid arthritis: a study of multidisciplinary team care with emphasis on vocational support.

OBJECTIVE: To explore changes in sick leave patterns and work ability in patients with early rheumatoid arthritis (RA). The patients received active team support focusing on vocational rehabilitation, in addition to treatment with disease-modifying anti-rheumatic drugs (DMARDs). METHODS: This is an observational study of 110 patients with early RA aged 18-60 years and not permanently disabled. All patients were monitored regularly during a 2-year period by a team comprising a nurse, an occupational therapist, a physiotherapist, a rheumatologist, and a social worker. Intervention included work-site visits and rehabilitation meetings with the employer and the official from the local social insurance office in addition to DMARD treatment and different individual treatments, and support from the team members. RESULTS: The number of patients working full-time increased from 65 to 74 (14%), those with full-time work disability decreased from 37 to 13 (65%), and patients working part-time increased from 8 to 23 (65%). This change was already evident during the first year. CONCLUSION: Active vocational support in addition to DMARD treatment may prevent or delay work disability in patients with early RA.

Adolescent↗

PubMedDate not supplied

Specification of electron beam quality from the central-axis depth absorbed-dose distribution.

The distribution of absorbed dose in a medium irradiated by broad electron beam has been analyzed from physical and therapeutic points of view. A number of parameters which describe the beam quality and the shape of the absorbed-dose distribution along the central axis are defined. Several comparisons are made of the values of these parameters obtained from measurements made on different therapy accelerators and from theoretically calculated dose distributions for monoenergetic and monodirectional beams. It is found that the major part of the observed differences between experimental and theoretical results can be attributed to the energy distribution of the accelerator beam and to processes in the scattering material, such as energy straggling and the production of secondary electrons and photons. A simple expression is derived relating the slower falloff in dose found for most accelerator beams to the large energy spread found in these beams. Further, a semiempirical relationship is found which makes it possible to obtain the mean electron energy at the phantom surface from the depth where the absorbed dose has decreased to 50% of its maximum value along the central axis.

Electrons↗

PubMedDate not supplied

Electron beam characteristics of the 50-MeV racetrack microtron.

Electron beams in the MM50 racetrack microtron are generated by computer controlled scanning of a well-focused electron pencil beam. The treatment head is optimized to give a minimum of scatter between the source position and the collimator plane by a general minimization of all scattering material in the beam and by replacement of the air in the treatment head by helium, which has a much lower linear scattering power than air. A double-focused multileaf collimator with a 31-cm collimator to patient distance is used both for electron and photon collimation. In general, no extra electron collimation is needed for the standard SSD of 100 cm. To make irregular field collimation at a distance this far from the patient possible, a number of requirements have to be fulfilled regarding the virtual source position and the spatial and angular distribution of the initial electron beam. The virtual source position has been found to be at a fixed position for different irradiation parameters. This is important for the use of the light field in electron beam treatment but also for achieving a high degree of accuracy in the dosimetry. Scatter from the multileaf collimator has not been found to give any significant contribution to the radiation field or to the monitor output factor of the MM50. Experimental dose distribution data on the MM50 have been compared to data both from other types of treatment units and to Monte Carlo simulations.

Electrons↗