Voluntary and involuntary adaptation of gait in Parkinson's disease

Voluntary and involuntary adaptation of gait in Parkinson's disease (PD) were studied in two separate experiments. In the first experiment, effects of changes in voluntary control were studied by asking PD patients and age-matched healthy subjects to adapt their walking pattern to visual cues resulting in spatial constraints, and auditory cues resulting in temporal constraints on stepping movements. In the second experiment, the adaptation to increases in speed during overground and treadmill walking was studied. Most patients were able to adapt their walking patterns in accordance with instructions. Notwithstanding consistent differences in step length, the adaptation to different conditions under study was highly similar in PD patients and healthy subjects. Only during walking with visually guided step length were the observed adaptations in PD patients less consistent. Contrary to these dissimilarities, the involuntary adaptation of timing of support and swing phases within the stride cycle was very similar between groups. In all conditions, only with changes in step length could a change in relative timing be observed. Our findings show that voluntary adaptation of gait is possible in PD and that basic involuntary coordination mechanisms are preserved. The observed disturbances in stride length regulation probably reflect an inability to perform fast movements in PD. Copyright 1998 Elsevier Science B.V.     

The survival motor neuron protein in spinal muscular atrophy

The 38 kDa survival motor neuron (SMN) protein is encoded by two ubiquitously expressed genes: telomeric SMN (SMN(T)) and centromeric SMN (SMN(C)). Mutations in SMN(T), but not SMN(C), cause proximal spinal muscular atrophy (SMA), an autosomal recessive disorder that results in loss of motor neurons. SMN is found in the cytoplasm and nucleus. The nuclear form is located in structures termed gems. Using a panel of anti-SMN antibodies, we demonstrate that the SMN protein is expressed from both the SMN(T) and SMN(C) genes. Western blot analysis of fibroblasts from SMA patients with various clinical severities of SMA showed a moderate reduction in the amount of SMN protein, particularly in type I (most severe) patients. Immunocytochemical analysis of SMA patient fibroblasts indicates a significant reduction in the number of gems in type I SMA patients and a correlation of the number of gems with clinical severity. This correlation to phenotype using primary fibroblasts may serve as a useful diagnostic tool in an easily accessible tissue. SMN is expressed at high levels in brain, kidney and liver, moderate levels in skeletal and cardiac muscle, and low levels in fibroblasts and lymphocytes. In SMA patients, the SMN level was moderately reduced in muscle and lymphoblasts. In contrast, SMN was expressed at high levels in spinal cord from normals and non- SMA disease controls, but was reduced 100-fold in spinal cord from type I patients. The marked reduction of SMN in type I SMA spinal cords is consistent with the features of this motor neuron disease. We suggest that disruption of SMN(T) in type I patients results in loss of SMN from motor neurons, resulting in the degeneration of these neurons.      

Pelvic masses in pregnant patients: MR and US imaging

Sixteen pregnant patients with pelvic masses detected with ultrasound (US) were studied with magnetic resonance (MR) imaging at 0.35 T. Two patients were in their first trimester, eight in the second, and six in the last. On MR images, 34 masses were seen, including 19 uterine leiomyomas. With US, 20 masses were detected. All masses not seen with US were leiomyomas. Only 20 masses (in 11 patients) were removed for histologic study. In nine cases, MR imaging and US provided similar information on the origin, extent, and type of mass. In seven patients, MR imaging contributed additional information. MR imaging depicted more leiomyomas than US in three patients. In another case, MR images showed that a mass depicted with US was actually a loop of bowel. MR images allowed differentiation between a solid soft-tissue mass and a hemorrhagic fluid-containing mass, correctly depicted the presence of an abdominal pregnancy, and allowed evaluation of the parametrium for spread of cervical carcinoma.     

Differences in constitutive and post-methotrexate folylpolyglutamate synthetase activity in B-lineage and T-lineage leukemia

Folylpolyglutamate synthetase (FPGS) is responsible for the metabolism of natural folates and a broad range of folate antagonists to polyglutamate derivatives. Recent studies indicated increased accumulation of methotrexate (MTX) polyglutamates (MTX-PG) in blast cells as a predictor of favorable treatment outcome in childhood acute lymphoblastic leukemia (ALL). We determined the expression of FPGS activity in blasts from children with ALL at diagnosis and after treatment with MTX as a single agent, before conventional remission induction therapy. The levels of enzyme activity in ALL blasts at diagnosis (median of 689 pmol/h/mg protein) were significantly higher (P = .003) than those found in acute nonlymphoblastic leukemia (ANLL) blasts (median of 181 pmol/h/mg protein). Comparable lineage differences in normal lymphoid versus nonlymphoid cells suggest a lineage-specific control of FPGS expression, FPGS activity increased in ALL blasts after in vivo exposure to MTX. The median increase in FPGS activity was significantly higher (P = .003) in B-lineage ALL (188%) than in T-lineage ALL (37%). Likewise, the percentage of intracellular long chain MTX-PG (Glu3-6) was significantly higher (P = .02) in B- lineage ALL (92%) than in T-lineage ALL (65%), consistent with higher FPGS activity in B-lineage blasts. This finding could explain, at least in part, the superior outcome in children with B-lineage ALL treated with antimetabolite therapy.     

药物代谢分型的研究进展

目的：为了促进药物代谢分型研究在临床上的深放。方法：综述近几年具遗传多态性代谢酶的探针药物、代谢分型方法以及影响因素。介绍“Cooktail”分型法。比较代谢分型与基因分型两种分型方法。结果:疾病、并用药物、探药剂量、样本处理方法、服药依从性是代谢分型的主要影响因素。结论：药物代谢分型能指导临床安全合理有效地用药。基因分型与代谢分型各有优点,应灵活应用。“Cooktail”分型方法具有独特的优越性和发展前景,应大力开展在特殊群体中的代谢分型研究。     

Peripheral blood progenitor cells for marrow reconstitution: mobilization and collection strategies

Previous studies of PBPC BMR have found evidence supporting its safety, feasibility, and efficacy when used in a wide range of patients. Although the optimal regimen for mobilization remains a focus of debate, data from the use of combinations of chemotherapy and cytokines suggest that there is more rapid white cell and platelet engraftment than with BMT, which leads to decreased transfusion requirements and, possibly, reduced patient care costs. Recent advances in the field include allogeneic PBPC BMR, negative selection of tumor cells to reduce contamination, and positive selection of CD34+ cells. These new strategies are anticipated to enhance the therapeutic effectiveness of PBPC BMR while minimizing toxicity. Still, the ultimate comparison of PBSC BMR and medullary BMT will depend on the results of well-designed, randomized, controlled clinical trials with long-term outcome analysis. However, the refinement and improvement of mobilization and collection techniques for PBPC BMR continue to add to the armamentarium of current therapeutic approaches for cancer and related nonmalignant conditions and will enable future strategies for ex vivo expansion of progenitor cells and use in gene transfer studies.