Centella asiatica triterpenes for diabetic neuropathy: a randomized, double-blind, placebo-controlled, pilot clinical study

BACKGROUND

Diabetic neuropathy (DN), a common complication of diabetes mellitus, results from hyperglycemia, poor microcirculation and attendant nerve damage. Currently available treatments relieve symptoms, but do not modify the neurodegeneration underlying DN. Centella asiatica (CA) triterpenes improved microcirculation in earlier clinical studies, and showed neurotropic effects in preclinical models suggesting a potential disease modifying effect in DN. This 52-week, randomized, double-blind, placebo-controlled trial examined the effects of CAST, a standardized CA extract containing triterpenes, on neuropathy symptoms in Type II diabetic subjects.

PATIENTS AND METHODS

The study enrolled patients with a history of Type II diabetes, with evidence of symptomatic symmetrical DN with total symptom score (TSS) ≥4, and stable HbA1c level <8. The primary outcome measure was TSS, which assessed intensity and frequency of parasthesia, numbness, pain and burning symptoms self-reported by patients. Secondary measures were nerve conduction, neurological impairment score, and quantitative sensory testing.

RESULTS

Comparing CAST (n=21) and Placebo (n=22) groups, significant reductions from baseline for TSS (p<0.01) and paresthesia (p<0.01) were seen only in CAST treated groups. Numbness increased from baseline only in the Placebo group (p<0.05) and was significantly higher than for the CAST group (p<0.001). Burning sensation was reduced in both groups (p<0.01). Plasma triterpene levels in patients treated with CAST mirrored neurotropic concentrations in vitro.

CONCLUSIONS

CAST is a potential oral treatment for diabetic neuropathy, as it is well tolerated and effective in reducing the severity of DN symptoms in patients with Type II diabetes.

The supplementary motor area contributes to the timing of the anticipatory postural adjustment during step initiation in participants with and without Parkinson's disease

The supplementary motor area (SMA) is thought to contribute to the generation of anticipatory postural adjustments (APAs, which act to stabilize supporting body segments prior to movement), but its precise role remains unclear. In addition, participants with Parkinson's disease (PD) exhibit impaired function of the SMA as well as decreased amplitudes and altered timing of the APA during step initiation, but the contribution of the SMA to these impairments also remains unclear. To determine how the SMA contributes to generating the APA and to the impaired APAs of participants with PD, we examined the voluntary steps of eight participants with PD and eight participants without PD, before and after disrupting the SMA and dorsolateral premotor cortex (dlPMC), in separate sessions, with 1-Hz repetitive transcranial magnetic stimulation (rTMS). Both groups exhibited decreased durations of their APAs after rTMS over the SMA but not over the dlPMC. Peak amplitudes of the APAs were unaffected by rTMS to either site. The symptom severity of the participants with PD positively correlated with the extent that rTMS over the SMA affected the durations of their APAs. The results suggest that the SMA contributes to the timing of the APA and that participants with PD exhibit impaired timing of their APAs, in part, due to progressive dysfunction of circuits associated with the SMA.

Cortical excitability and age-related volumetric MRI changes

OBJECTIVE

Normative data on transcranial magnetic stimulation (TMS)-derived measures of cortical excitability in the elderly is sparse. Nevertheless, elderly subjects are included as controls in studies utilizing TMS to investigate disease states. Age-associated increased ventricular cerebrospinal fluid CSF (vCSF) and white matter hyperintensity (WMH) MRI volumes have uncertain significance in non-demented elderly. Information regarding cortical excitability in neurologically intact elderly would augment our understanding of the pathophysiology of aging and assist in the interpretation of TMS studies involving elderly subjects.

METHODS

Twenty-four healthy elderly subjects underwent TMS testing to determine outcomes of resting motor threshold (RMT) cortical silent period (cSP) and central motor conduction time for examination in relation to WMH, vCSF, and CNS volumes.

RESULTS

Increased vCSF and WMH volumes were associated with decreased right and left hemisphere RMT. Smaller CNS volumes were associated with decreased right hemisphere RMT and shorted cSP.

CONCLUSIONS

Commonly observed age-associated MRI changes are associated with findings consistent with increased cortical excitability.

SIGNIFICANCE

Age-related MRI findings likely reflect changes at a cellular level, and may influence cognitive and motor integrity in the elderly. Future TMS studies investigating cortical excitability may wish to consider neuroimaging markers of neurodegeneration prior to enrolling elderly subjects as controls.

Movement precues in planning and execution of aiming movements in Parkinson's disease

Two experiments tested how changing a planned movement affects movement initiation and execution in idiopathic Parkinson's disease (PD) patients. In Experiment 1, PD patients, elderly controls, and young adults performed discrete aiming movements to one of two targets on a digitizer. A precue (80% valid cue and 20% invalid cue of all trials) reflecting the subsequent movement direction was presented prior to the imperative stimulus. All groups produced slower reaction times (RTs) to the invalid precue condition. Only the subgroup of patients with slowest movement time showed a significant prolongation of movement for the invalid condition. This suggests that, in the most impaired patients, modifying a planned action also affects movement execution. In Experiment 2, two-segment aiming movements were used to increase the demand on movement planning. PD patients and elderly controls underwent the two precue conditions (80% valid, 20% invalid). Patients exhibited longer RTs than the controls. RT was similarly increased for the invalid condition in both groups. The patients, however, exhibited longer movement times, lower peak velocities, and higher normalized jerk scores of the first segment in the invalid condition compared to the valid condition. Conversely, the controls showed no difference between the valid and invalid cue conditions. Thus, PD patients demonstrated substantially pronounced movement slowness and variability when required to change a planned action. The results from both experiments suggest that modifying a planned action may continue beyond the initiation phase into the execution phase in PD patients.

[Inhibitive effect of puerarin on increased NO production by neonatal cardiomyocytes during hypoxia/reoxygenation injury]

OBJECTIVE

To investigate the effect of puerarin (Pue) on nitric oxide (NO) produced by neonatal rat cardiomyocytes during hypoxia/reoxygenation injury.

METHOD

NO contents in the culture supernatants sampled from different groups (control, model, and therapeutic groups with 1, 0.1, 0.01 g.L-1 Pue) at different time were assayed with nitrate reductase method.

RESULT

NO content of model increased after reperfusion (P < 0.01), while it increased sharply at 6 h after reperfusion and kept thereafter. Only at 6 h after reperfusion did Pue in these three doses inhibit NO production (P < 0.01) and kept to the 24 h after reperfusion.

CONCLUSION

Pue exerts inhibitive effect only after NO production is enhanced sharply during hypoxia/reperfusion injury in a dose-dependent trend.

Exacerbated physical fatigue and mental fatigue in Parkinson's disease

OBJECTIVE

To characterize fatigue in Parkinson's disease (PD).

BACKGROUND

Fatigue is a recognized problem in PD. Fatigue can be in the physical realm or in the mental realm. Fatigue has not been characterized in PD.

METHODS

We characterized fatigue in 39 PD patients and 32 age-matched normal controls using five questionnaires: A. The Multidimensional Fatigue Inventory (MFI), which measures five dimensions of fatigue independently including general fatigue, physical fatigue, reduced motivation, reduced activity, and mental fatigue. B. The Fatigue Severity Inventory (FSI), which quantifies fatigue in general. C. The Profile of Mood States (POMS), which assesses six subjective subscales: tension-anxiety, depression-dejection, anger-hostility, fatigue-inertia, vigor-activity, and confusion-bewilderment. D. Center for Epidemiological Studies-Depression Scale (CES-D). E. Visual Analog linear scale of energy (VA-E).

RESULTS

PD patients scored higher in all of the five dimensions of fatigue in the MFI including general fatigue, physical fatigue, reduced motivation, reduced activity, and mental fatigue (P < 0.001 except for mental fatigue P = 0.005). The severity of physical fatigue did not correlate with that of mental fatigue. PD patients scored higher on the FSI, POMS, CES-D, and scored lower on the VA-E. The scores in the FSI correlated with general fatigue, physical fatigue, reduced activity, and reduced motivation but not with mental fatigue in the MFI. Depression correlated with all dimensions of fatigue except physical fatigue in the MFI. Disease severity, as measured by Modified Hoehn and Yahr staging, did not correlate with any of the measures.

CONCLUSIONS

PD patients have increased physical fatigue and mental fatigue compared to normals. Physical fatigue and mental fatigue are independent symptoms in PD that need to be assessed and treated separately.

Refsum's disease: long term treatment preserves sensory nerve action potentials and motor function

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Effects of diminished and conflicting sensory information on balance in patients with cerebellar deficits

We studied the effects of altered sensory information on standing balance in 25 patients with cortical cerebellar atrophy (CCA), nine patients with olivoponto-cerebellar atrophy (OPCA), and 10 normal subjects. The total sway path and its components, the anteroposterior (AP) sway path and the lateral sway path, were measured under six conditions: (1) standing on a fixed platform with the eyes open and visual surroundings fixed, (2) standing on a fixed platform with the eyes closed, (3) standing on a fixed platform with the eyes open and visual surroundings AP sway referenced, (4) standing on an AP sway-referenced platform with the eyes open and visual surroundings fixed, (5) standing on an AP sway-referenced platform with the eyes closed, and (6) standing on an AP sway-referenced platform with the eyes open and visual surroundings AP sway referenced. Patients swayed more than normal subjects during normal stance (condition 1), when the visual information was absent (condition 2) or distorted (condition 3), and when the proprioceptive information from the ankles was distorted (condition 4). Patients swayed much more than normal, and most fell, when two sensory modalities were affected under condition 5 (proprioceptive information distorted and visual information absent) and condition 6 (both proprioceptive information and visual information distorted). When the patients' sway was normalized to that of the first condition, however, only their lateral sway was greater than the sway in normal subjects. Unlike in normal subjects, the patients' lateral sway varied with the AP sway to approximately the same degree in each condition for conditions 1-5. Clinical ratings of gait and balance were highly correlated with the sway measures. Quantitative testing of standing balance with altered sensory information has better sensitivity than normal stance testing.

Preserved cognitive processes in cerebellar degeneration

Aspects of cognitive processing in patients with cerebellar degeneration (CD) were studied in order to examine the validity of recent findings that CD patients demonstrate deficits in visuospatial cognition and verbal-associative learning. Two groups of patients with CD were compared to stratified matched control groups on tests examining selective visual attention, visual spatial attention, mental rotation of geometric designs, and memory for the temporal order of words they were previously exposed to. CD patients performed similarly to their matched controls across all tasks. These results indicate that the reported cognitive deficits of CD patients are quite selective and need further specification in order to more fully describe their relationship to cerebellar dysfunction.

Use of buspirone for treatment of cerebellar ataxia. An open-label study

OBJECTIVE

To evaluate the efficacy of buspirone hydrochloride, a serotonin (5-hydroxytryptamine1A) agonist, in treating patients with cerebellar ataxia.

DESIGN

Open-label study in which 20 patients (14 with cerebellar cortical atrophy and six with olivopontocerebellar atrophy) received buspirone hydrochloride, up to 60 mg/d, for 8 weeks.

SETTING

Research hospital.

MAIN OUTCOME MEASURES

Clinical, physiological, and psychological assessment.

RESULTS

Nine patients with mild or moderate cerebellar dysfunction who completed the study showed significant improvement in clinical and self-assessment ratings, but not in a motor performance test, posturography (data were incomplete), State-Trait Anxiety Inventory, and Beck Depression Inventory. Seven patients with severe cerebellar dysfunction who completed the study had no improvement on any measure.

CONCLUSIONS

Buspirone may be effective in treating mild to moderate cerebellar ataxia. A double-blind study of the efficacy of buspirone in cerebellar ataxia is warranted.

Regional cerebral blood flow during a self-paced sequential finger opposition task in patients with cerebellar degeneration

The brain regions controlling self-paced sequential finger movements in patients with cerebellar degeneration were studied by measuring changes in regional cerebral blood flow (rCBF) in eight patients using bolus injections of H2(15)O and PET. The results were compared with those obtained in eight normal age-matched control subjects. Patients and control subjects performed a self-paced sequential finger opposition task with the right hand, completing a sequence of movements every 4-6 s. Both groups had strong increases in the adjusted rCBF contralaterally in the primary motor cortex (M1) and ventral premotor area (PMv), in the caudal supplementary motor area (SMA) and cingulate motor area (CMA), and bilaterally in the prefrontal cortex (PFC), the lobus parietalis inferior (LPI), putamen and cerebellum. The cerebellum, PMv, rostral CMA, PFC and LPI were more active in the control subjects than in the patients, and the M1, SMA, caudal CMA and putamen were more active in the patients than in the control subjects. The reduced activity of the cerebellar neurons in the patients produced a complex pattern of rCBF increases and decreases in other brain regions. Our results suggest that for the preparation and execution of sequential finger movements, patients with cerebellar degeneration use a medial premotor system, including the SMA and caudal CMA, as well as the M1 and putamen, rather than the PMv, PFC, LPI and rostral CMA.

Brainstem reflexes in patients with olivopontocerebellar atrophy

In 4 patients with familial olivopontocerebellar atrophy (OPCA) we have recently described an abnormal movement of facial muscles characterized by rhythmic muscle twitching during voluntary activation (facial action myoclonus). In the present article, we present the results of a neurophysiological study of brainstem reflexes in those 4 patients, in 4 other patients with OPCA but without facial action myoclonus, in 3 patients with pure cerebellar cortical atrophy, and in 6 normal volunteers used as control subjects. All patients had similar clinical features, but only the patients with facial action myoclonus and only one of the other patients with OPCA had brainstem atrophy detected on magnetic resonance imaging. Electrophysiological abnormalities were found in all patients with facial action myoclonus and consisted of myokymia in perioral muscles at rest, spread of spontaneous and reflex blinking to the orbicularis oris, and enhanced long-latency facial reflex responses to stimuli applied to the facial or trigeminal nerve. Other relevant electrophysiological abnormalities were the absence of jaw jerk in 2 patients, the absence of an R1 response of the blink reflex in 1 patient, and a markedly reduced compound muscle action potential of the facial nerve in another patient. Comparable electrophysiological abnormalities were found in only 1 of the patients with OPCA but without facial action myoclonus, and in none of the patients with pure cerebellar cortical atrophy. Facial action myoclonus is a clinical manifestation of a global brainstem functional derangement that may characterize a subgroup of patients with OPCA or constitute a distinctive step in the natural evolution of some forms of the disease.

Facial action myoclonus in patients with olivopontocerebellar atrophy

We studied four patients with familial olivopontocerebellar atrophy (OPCA) who had abnormal twitching of the cheeks and perioral muscles induced by facial movements. With the muscles at rest, electromyographic (EMG) recordings of the orbicularis oris and risorius muscles revealed myokymic discharges in the absence of visible movements. With voluntary contraction, the EMG showed synchronous discharges in the orbicularis oris and risorius muscles ipsilaterally associated with visible twitching. The duration of the EMG bursts was 10 to 75 ms with a frequency of 8 to 25 Hz, which suggested that the abnormal twitching was most consistent with a myoclonic disorder. Because it was induced by activation of the facial muscles, this movement disorder represents a form of action myoclonus.

Long-term botulinum toxin treatment of focal hand dystonia

We treated focal hand dystonia in 53 patients with botulinum toxin injections for up to 6 years. Eighty-one percent of the patients improved with at least one injection session. Sixty-five percent of the injections produced transient weakness. We followed 37 of the patients for at least 2 years from the start of treatment, 24 of whom discontinued treatment because of inadequate response, loss of response, inaccessibility of a treatment provider, or the expense of the toxin. Women, who had a greater extent and longer duration of benefit than men, were more likely to continue treatment. The mean interval between injection sessions was 6 months. In most patients, we injected the toxin into the same combination of muscles at each session. The dose of toxin generally fluctuated within a range of 20 units. Side effects were mild and transient and unrelated to the long-term use of botulinum toxin. Botulinum toxin injection is safe and effective for the long-term management of focal hand dystonia.

Procedural learning in Parkinson's disease and cerebellar degeneration

We compared procedural learning, translation of procedural knowledge into declarative knowledge, and use of declarative knowledge in age-matched normal volunteers (n = 30), patients with Parkinson's disease (n = 20), and patients with cerebellar degeneration (n = 15) by using a serial reaction time task. Patients with Parkinson's disease achieved procedural knowledge and used declarative knowledge of the task to improve performance, but they required a larger number of repetitions of the task to translate procedural knowledge into declarative knowledge. Patients with cerebellar degeneration did not show performance improvement due to procedural learning, failed to achieve declarative knowledge, and showed limited use of declarative knowledge of the task to improve their performance. Both basal ganglia and cerebellum are involved in procedural learning, but their roles are different. The normal influence of the basal ganglia on the prefrontal cortex may be required for timely access of information to and from the working memory buffer, while the cerebellum may index and order events in the time domain and be therefore essential for any cognitive functions involving sequences.

Responses of sagittally aligned Purkinje cells during perturbed locomotion: relation of climbing fiber activation to simple spike modulation

1. The purpose of these experiments is to test the hypothesis that the synchronous activation of sagittally aligned Purkinje cells by a physiologically relevant stimulus is associated with an increase in the simple spike responses of the same neurons. 2. This hypothesis was tested using a perturbed locomotion paradigm in decerebrate locomoting ferrets. The responses of 3-5 sagittally aligned Purkinje cells were recorded simultaneously in response to the intermittent perturbation of the forelimb during swing phase. A data analysis is introduced, the real time postsynaptic response (RTPR), that permits the quantification of the simple spike responses of Purkinje cells in a manner that can be related to their complex spike responses on a trial-by-trial basis. 3. The data support the above hypothesis by illustrating that the amplitude of the combined simple spike responses across the population of Purkinje cells is correlated with the extent to which their climbing fiber inputs are synchronously activated. These findings together with an analysis of the gain-change ratio support the view that the synchronous climbing fiber input may be responsible for mediating this increased responsiveness. 4. More generally, the data suggest that the task- and/or behaviorally dependent activation of sagittal strips of climbing fiber inputs may provide a mechanism whereby the responsiveness of discrete populations of Purkinje cells can be selectively regulated, specifying the groups of neurons that will be most dramatically modulated by mossy fiber inputs activated by the same conditions.

Responses of sagittally aligned Purkinje cells during perturbed locomotion: synchronous activation of climbing fiber inputs

1. These experiments were performed to test the hypothesis that climbing fiber inputs to sagittally aligned Purkinje cells located in a single folium are activated synchronously in response to a perturbation of the step cycle that interrupts the trajectory of the ipsilateral forelimb. 2. The experiments were performed in acutely decerebrate ferrets capable of walking spontaneously on a moving treadmill. A multiple single-unit recording technique was employed utilizing a fixed array of five sagittally oriented electrodes with electrode tips approximately 200 microns apart. 3. The extent to which the climbing fiber inputs to the recorded Purkinje cells were activated synchronously by the perturbation was calculated for individual trials by determining the synchrony index, a measure of the fraction of the cells responding to each perturbation. 4. The data indicate that there was a statistically significant increase in the synchronous activation of climbing fiber inputs at times immediately after the perturbation. No comparable complex spike modulation was found at the same phase of the unperturbed step cycle. 5. The specific combinations of climbing fiber inputs to neighboring Purkinje cells activated by successive perturbations varied from trial to trial. 6. The implications of these observations are discussed in the context of the nature of the inputs encoded by climbing fiber activation and the role of this afferent system in cerebellar cortical information processing.

Essential tremor: clinical correlates in 350 patients

To study the demographic and clinical correlates of essential tremor (ET), we analyzed a comprehensive database of 350 patients evaluated at the Movement Disorders Clinic at Baylor College of Medicine from 1982 to 1989. The age at onset of tremor showed bimodal distribution for both male and female patients, with peaks in 2nd and 6th decades. ET appeared most frequently in hands, followed by head, voice, tongue, leg, and trunk. Half of the patients (47%) had associated dystonia, including cervical dystonia, writer's cramp, spasmodic dysphonia, and cranial dystonia, and 20% of the patients had associated parkinsonism. At least one 1st-degree relative of 62.5% of ET patients reported tremor. Alcohol relieved tremor in 2/3 of ET patients. Sixty-eight percent of patients who had adequate follow-up improved with propranolol, and 72% with primidone. There was no significant difference in various clinical variables between the 219 patients with familial ET and 131 with sporadic ET. Patients with early-onset ET were more likely to have hand involvement and associated dystonia than patients with late-onset ET. Dystonia was more frequently associated with mild ET than with severe ET. Patients with low-frequency tremor were older and had more head but less hand involvement than patients with high-frequency tremor. The lack of relevant differences between ET subgroups suggests that, despite variable expression, ET represents a single disease entity.

A study of cerebellar cortical involvement in motor learning using a new avoidance conditioning paradigm involving limb movement

These experiments were performed to examine the relationship between the simple and complex spike responses of 3-5 simultaneously recorded Purkinje cells during the acquisition, performance and extinction of a conditioned forelimb movement in decerebrate, unanesthetized ferrets. The data demonstrate parallel, correlated changes in simple and complex spike responses throughout the experimental period. Since the evaluated Purkinje cells were examined in the cerebellar cortical region that contains neurons highly modulated by the intermittent application of the conditioning stimulus, these findings argue against an induction of a long-lasting modification in simple spike responses by the climbing fiber input as the basis for this type of motor learning.

A new conditioning paradigm: conditioned limb movements in locomoting decerebrate ferrets

These experiments address the hypothesis that the trajectory of a forelimb in decerebrate ambulating ferrets can be conditioned to avoid an obstacle encountered during the locomotor cycle. The perturbation was produced by interjecting a bar into the trajectory of the forelimb during swing phase. Over 5-15 steps the flexion of the elbow progressively increased until the forelimb was elevated over the bar. Avoiding the bar often required that the maximum height of the paw during swing phase was doubled. When the bar was no longer thrust into the trajectory of the forelimb, the conditioned behavior persisted for several step cycles. The results indicate that decerebrate ferrets are capable of acquiring a conditioned limb movement that is not a typical conditioned reflex but rather an accentuation of a component of the step cycle performed to avoid an interruption of swing phase.

The responses of simultaneously recorded Purkinje cells to the perturbations of the step cycle in the walking ferret: a study using a new analytical method--the real-time postsynaptic response (RTPR)

Experiments were performed in ambulating decerebrate ferrets to examine the activity of up to 6 simultaneously recorded Purkinje cells oriented sagittally during unperturbed and perturbed locomotion using a new analytical technique, the real-time postsynaptic response (RTPR), which permits a trial-by-trial assessment of the action of the recorded neurons on a simulated cerebellar nuclear cell. The data illustrate that the responsiveness of the Purkinje cells located in a specific region of lobules V and VI is most dramatically modulated by the perturbations of the locomotor cycle and that this responsiveness in the perturbed trials is related to the degree of synchrony of the activated climbing fiber inputs to the cells of the set. The data were interpreted as supporting the gain change hypothesis of climbing fiber function.