Visual guidance of the human foot during a step

When the intended foot placement changes during a step, either due to an obstacle appearing in our path or the sudden shift of a target, visual input can rapidly alter foot trajectory. However, previous studies suggest that when intended foot placement does not change, the path of the foot is fixed after it leaves the floor and vision has no further influence. Here we ask whether visual feedback can be used to improve the accuracy of foot placement during a normal, unperturbed step. To investigate this we measured foot trajectory when subjects made accurate steps, at fast and slow speeds, to stationary floor-mounted targets. Vision was randomly occluded in 50% of trials at the point of foot-off. This caused an increase in foot placement error, reflecting lower accuracy and higher variability. This effect was greatest for slow steps. Trajectory heading analysis revealed that visually guided corrections occurred as the foot neared the target (on average 64 mm away). They occurred closer to the target for the faster movements thus allowing less time and space to execute corrections. However, allowing for a fixed reaction time of 120 ms, movement errors were detected when the foot was approximately halfway to the target. These results suggest that visual information can be used to adjust foot trajectory during the swing phase of a step when stepping onto a stationary target, even for fast movements. Such fine control would be advantageous when environmental constraints place limitations on foot placement, for example when hiking over rough terrain.     

Standardized quick en bloc technique for procurement of cadaveric liver grafts for pediatric liver transplantation

This paper describes a quick procedure for cadaveric liver graft retrieval during multiple organ harvesting. The technique is based on minimal preliminary dissection, absence of in situ direct portal perfusion, and en bloc removal of the liver and pancreas, with an aortic patch encompassing the coeliac trunk and superior mesenteric artery. The results of 110 pediatric liver transplantations with 109 organs harvested using this technique are reported. There were no graft harvesting injuries. The liver graft primary nonfunction rate was 4.5% (5/110). The 3-month retransplantation rate was 10%. The actual patient survival rates were 93% at 3 months and 90% at 1 year; actual graft survival rates were 85.5% and 78%, respectively. The technique described was at least as safe as conventional procedures. A major advantage of the procedure is its flexibility, which allows for the easily combined procurement of other organs (whole pancreas and intestine).     

Neurotropic melanoma with prominent melanization

Neurotropic melanoma has generally been described in the context of desmoplastic melanoma. The vast majority of melanomas displaying neurotropism contain relatively little or no melanin. Herein, we report an unusual case of neurotropic melanoma with prominent melanin content. The patient developed a tumor notable For pagetoid (superficial spreading) melanoma with partial regression and a deep component characterized by perineurial aggregates of melanophages and intraneural infiltration by melanoma cells. This case serves to alert dermatopathologists to the fact that the spectrum of neurotropic melanoma includes tumors with perineurial aggregates of pigment-containing cells.     

Citation patterns in the International Journal of Geriatric Psychiatry: Cultural ethnocentrism revisited?

The country/region of origin of all original papers appearing in the International Journal of Psychiatry (IJGP) during the first 9 years of its publication was recorded. A more detailed analysis of citation patterns was carried out on the 105 original articles published during 1992. The results indicated that 50–60% of the articles emanated from the United Kingdom but that in general authors cited a broad range of specialities from journals published around the world. North American authors tended to cite North American sources more frequently than did their counterparts from other countries. There was evidence that the impact of the IJGP is increasing despite its omission from some scientific reference databases.     

Clinical pharmacokinetics of Neoral in pediatric recipients of primary liver transplants

Pediatric liver transplant recipients constitute a population characterized by a particularly unpredictable and poor bioavailability of cyclosporin (CyA). Even though several adult studies show that the new oral formulation of CyA, Neoral (NEO), produces better bioavailability and blood level predictability, few data describe its pharmacokinetics in children. We performed a complete analysis of the pharmacokinetics of NEO in ten small children after primary liver transplantation. Three pharmacokinetic profiles were set up with data obtained from tests taken during i. v. administration of CyA, after the first oral NEO dose, and after the last NEO dose before discharge from the hospital. The mean half-lives obtained were 8.1, 7.7, and 6.9 h, respectively, and the bioavailabilities were 22 % and 21 % for the first and last NEO doses. A large interpatient variability was observed. This was due, in part, to episodes of diarrhea that interfered with the pharmacokinetic evaluation and, in part, to the variability of post-transplant hepatic function. There was a good correlation between CyA trough levels and their related AUCs for both NEO profiles (r = 0.93 and r = 0.74, respectively). We conclude that, even though the pediatric OLT population remains more unpredictable than that of adults, NEO has a relatively rapid half-life and a remarkably improved bioavailability. Received: 29 November 1996 Received after revision: 10 April 1997 Accepted: 15 May 1997     

An investigation into the effects of structured music workshops with adults with mental handicap

This study investigated the effects of structured group workshops for a population with special needs. Twenty subjects, each with a mild or moderate mental handicap, attended a series of 10 weekly 1-hour music workshops on the structured group playing of a Javanese Gamelan. Twenty subjects formed a non-intervention control group. The experimental hypothesis was that participation in the experimental group would produce significant improvements in musical ability as measured by the Rossi test of musical ability, devised and validated for use in this study. Significant gains in communication skills as measured by the Communication Assessment Profile for Adults with a Mental Handicap (CASP) and self-esteem levels measured by the Khalid semantic differential technique were also postulated. It was also suggested that these gains would be significantly correlated. Results show significant gains in musical ability (instrumental rhythm production: t = 5.67, d.f. = 29, p < 0.01 and simple rhythm production: t = 8.42, d.f. = 29, p < 0.01) and communication skills (t = 4.69, d.f. = 29, p < 0.01). Moreover these results are significantly correlated (r = 0.59, p < 0.05, r = 0.75, p < 0.05, r = 0.56, p < 0.05). A ceiling effect was obtained in the measurement of self-esteem. It is suggested that these gains derive from certain aspects of the musical communicative environment at the workshops. Suggestions for future research involve examining the possible influences on these developments.     

Does the Prepubertal Duration of Diabetes Influence the Onset of Microvascular Complications?

This study investigated the relationship between the development of diabetic retinopathy and pubertal status at onset of diabetes in 521 Type 1 diabetic patients diagnosed between 1950 and 1985. Pubertal status was based on age at onset (girls ≧ 11 years and boys ≧ 12 years). Retinopathy (all forms) developed in 112 patients (21.5%; 65 background and 47 proliferative retinopathy). For subjects diagnosed in either the prepubertal or postpuberal period, a similar proportion survived without developing retinopathy for any given duration of diabetes (X² = 0.3822, p = 0.54). However, if only the postpubertal duration of diabetes is considered, then the proportion of patients surviving without retinopathy was significantly less for those diagnosed in the prepubertal period (X² = 14.2, p = 0.002). This study suggests that the prepubertal duration of diabetes is an important phase and that the years prior to puberty do contribute to the risk of developing microvascular injury.     

Cyclophosphamide and etoposide therapy with GM-CSF for VAD-resistant multiple myeloma

Few effective regimens are available for patients with advanced multiple myeloma resistant to or relapsing after both alkylating agents and VAD. We treated 52 patients with advanced and refractory multiple myeloma with the combination of cyclophosphamide (3.0 g/m²) and etoposide (900 mg/m²) followed by GM-CSF at a daily dose of 0.125 mg/m² until recovery of granulocytes. 42% of patients responded with a median time of 19 d for recovery of granulocytes to 0.5 x 10⁹/1 and a 4% mortality rate. Eight responding patients received a second myeloablative treatment supported by either autologous bone marrow (six patients) or blood stem cells (two patients). The median survival time for all patients was 11 months and the median remission time for responding patients was 8 months. The combination of cyclophosphamide and etoposide provided an effective rescue treatment for many patients with advanced multiple myeloma resistant to conventional therapies. This programme also allowed early marrow or blood stem cell collection in support of subsequent myeloablative therapy for selected patients.     

SODIUM EFFECTS ON THE FIBRILLATORYPROPENSITY OF NON-IONIC CONTRAST MEDIA

Removing sodium from standard ionic contrastmedia markedly increases the incidence of ventricu-lar fibrillation in patients undergoing coronary arvgiography. Newer nonionic contrast media, Iopa-midol (IOP), Iohexol (IOH) and Ioversol (IOV),contain only trace amounts of sodium. To determinewhether sodium influences the fibrillatory propen-sity of nonionic contrast media, we measured theprolongation in QT interval and performed program-med electrical stimulation with l,2 and 3 ventricularextra stimuli in 40 dogs during 4 ml intracoronaryinjections of IOP, IOH and IOV. Solutions of eachcontrast media with added NaCI at concentrations of0.225To, 0.45% and 0.970 were compared to stockcontrast media. The addition of NaCI markedlyincreased the amount of QT interval prolongationproduced by each contrast media. With IOP, theamount of QT interval prolongation was 40+11msec with standard IOP but was 58+11 msec with0.225'70 NaCI/IOP, 84+17 msec with 0.45'To NaCI/IOP, and 132+42 msec with 0.970 NaCl/IOP(P相似文献