Elevated lactate and alkalosis in chronic human brain infarction observed by 1H and 31P MR spectroscopic imaging.

The goal of this study was to investigate lactate and pH distributions in subacutely and chronically infarcted human brains. Magnetic resonance spectroscopic imaging (MRSI) was used to map spatial distributions of 1H and 31P metabolites in 11 nonhemorrhagic subacute to chronic cerebral infarction patients and 11 controls. All six infarcts containing lactate were alkalotic (pHi = 7.20 +/- 0.04 vs. 7.05 +/- 0.01 contralateral, p less than 0.01). This finding of elevated lactate and alkalosis in chronic infarctions does not support the presence of chronic ischemia; however, it is consistent with the presence of phagocytic cells, gliosis, altered buffering mechanisms, and/or luxury perfusion. Total 1H and 31P metabolites were markedly reduced (about 50% on average) in subacute and chronic brain infarctions (p less than 0.01), and N-acetyl aspartate (NAA) was reduced more (approximately 75%) than other metabolites (p less than 0.01). Because NAA is localized in neurons, selective NAA reduction is consistent with pathological findings of a greater loss of neurons than glial cells in chronic infarctions.

Conceptual approach to diagnostic delay in ALS: a United States perspective.

The mean time from onset of symptoms to confirmation of diagnosis of amyotrophic lateral sclerosis (ALS) in the United States, as elsewhere, is 16-18 months. Delays may arise from the complex referral pathway, caused at least in part by the multiple types of insurance and health-care services available in the United States and also because physicians sometimes attempt to avoid medicolegal responsibility for a very undesirable diagnosis. In addition, initial symptoms are often intermittent and nonspecific and may be denied or not recognized by the patient. In the United States, the primary care physician is increasingly viewed by health maintenance organizations as a gatekeeper, with incentives to keep the diagnosis within the primary care realm. This may lead to misdiagnosis and inappropriate referral. Even after the patient reaches a neurologist, the differential diagnosis of ALS is large and may involve many tests, all of which may incur scheduling and reporting delays. Reluctance to give a bad diagnosis before it is absolutely certain may also cause delay. Delays after diagnosis may be the result of health insurance constraints, the prejudices of the neurologist in favor of or against particular therapies, and the patient's willingness to accept or ability to pay for therapy. Many of these delays may be lessened by both professional and lay educational initiatives to raise awareness of the symptoms of ALS and encourage more rapid presentation and referral to the neurologist. The availability of credible treatment options would undoubtedly encourage physicians to have hope and to seek an earlier diagnosis.

Decreased N-acetylaspartate in motor cortex and corticospinal tract in ALS.

The primary objectives of this study were to test whether 1) N-acetylaspartate (NAA), a neuronal marker, is reduced in motor cortex and corticospinal-tract (CST) brain regions of ALS patients; and 2) motor cortex NAA correlates to a clinical measurement of upper motor neuron function in ALS patients. Ten probable or definite ALS patients and nine neurologically normal control subjects were studied. Three axial planes of two-dimensional 1H MRSI data were collected, using a single spin-echo multislice sequence (TE140/TR2000). Two of the 1H MRSI planes were positioned superior to the lateral ventricles, and one plane was positioned at the level of the internal capsule. Spectroscopy voxels were selected from motor cortex, frontal cortex, parietal cortex, medial gray matter, centrum semiovale white matter, anterior internal capsule, and posterior internal capsule. Peak integrals were obtained for the three major 1H MRSI singlet resonances, NAA, creatine and phosphocreatine (Cr), and cholines (Cho). Maximum finger-tap rate was used as a clinical measurement of upper motor neuron function. In ALS, brain NAA/(Cho+Cr) was reduced 19% (p=0.024) in the motor cortex and 16% (p=0.021) in the CST (centrum semiovale and posterior internal capsule) regions. NAA/ (Cho+Cr) was not reduced in frontal cortex, parietal cortex, medial gray matter, or anterior internal capsule. There was a significant relation between ALS motor cortex NAA/(Cho+Cr) and maximum finger-tap rate (r=0.80; p=0.014). NAA/(Cho+Cr) was reduced in motor cortex and CST regions and unchanged in other brain regions of ALS patients when compared with controls. These findings are consistent with the known distribution of neuronal loss in ALS. The positive correlation between motor cortex NAA/(Cho+Cr) and maximum finger-tap rate suggests that reduced NAA/(Cho+Cr) is a surrogate marker of motor cortex neuron loss in ALS. These findings support the study of 1H MRSI NAA measurement as an objective and quantitative measurement of upper motor neuron dysfunction in ALS.

Early detection and longitudinal changes in amyotrophic lateral sclerosis by (1)H MRSI.

OBJECTIVE: To determine 1) the reproducibility of metabolite measurements by (1)H MRS in the motor cortex; 2) the extent to which (1)H MRS imaging (MRSI) detects abnormal concentrations of N-acetylaspartate (NAA)-, choline (Cho)-, and creatine (Cre)-containing compounds in early stages of ALS; and 3) the metabolite changes over time in ALS. METHODS: Sixteen patients with definite or probable ALS, 12 with possible or suspected ALS, and 12 healthy controls underwent structural MRI and multislice (1)H MRSI. (1)H MRSI data were coregistered with tissue-segmented MRI data to obtain concentrations of NAA, Cre, and Cho in the left and right motor cortex and in gray matter and white matter of nonmotor regions in the brain. RESULTS: The interclass correlation coefficient of NAA was 0.53 in the motor cortex tissue and 0.83 in nonmotor cortex tissue. When cross-sectional data for patients were compared with those for controls, the NAA/(Cre + Cho) ratio in the motor cortex region was significantly reduced, primarily due to increases in Cre and Cho and a decrease in NAA concentrations. A similar, although not significant, trend of increased Cho and Cre and reduced NAA levels was also observed for patients with possible or suspected ALS. Furthermore, in longitudinal studies, decreases in NAA, Cre, and Cho concentrations were detected in motor cortex but not in nonmotor regions in ALS. CONCLUSION: Metabolite changes measured by (1)H MRSI may provide a surrogate marker of ALS that can aid detection of early disease and monitor progression and treatment response.

Clinical trials of riluzole in patients with ALS. ALS/Riluzole Study Group-II.

Two double-blinded, placebo-controlled clinical trials of riluzole have now been carried out in more than 1,100 patients with ALS. The results of both studies show a modest benefit in prolonging survival that is statistically significant. These results led to the availability of this drug by the Food and Drug Administration for use in the United States beginning in early 1996. This is the first drug that has been available for ALS. It begins a new era in both basic and clinical research in an attempt to find a cure for this disease.

Effect of recombinant human insulin-like growth factor-I on progression of ALS. A placebo-controlled study. The North America ALS/IGF-I Study Group.

The objective of this study was to investigate the safety and efficacy of recombinant human insulinlike growth factor-I (rhIGF-I) in the treatment of sporadic ALS. A double-blind, placebo-controlled, randomized study of 266 patients was conducted at eight centers in North America. Placebo or rhIGF-I (0.05 mg/kg/day or 0.10 mg/kg/day) was administered for 9 months. The primary outcome measure was disease symptom progression, assessed by the rate of change (per patient slope) in the Appel ALS rating scale total score. The Sickness Impact Profile (SIP), a patient-perceived, health-related quality of life assessment, was a secondary outcome variable. Progression of functional impairment in patients receiving high-dose (0.10 mg/kg/day) rhIGF-I was 26% slower than in patients receiving placebo (p = 0.01). The high-dose treatment group was less likely to terminate the study due to protocol-defined markers of disease symptom progression, and members in this group exhibited a slower decline in quality of life, as assessed by the SIP. Patients receiving 0.05 mg/kg/day of rhIGF-I exhibited trends similar to those associated with high-dose treatment, suggesting a dose-dependent response. The incidence of clinically significant adverse experiences was comparable among the three treatment groups. Recombinant human insulin-like growth factor-I slowed the progression of functional impairment and the decline in health-related quality of life in patients with ALS with no medically important adverse effects.

Placebo-controlled trial of gabapentin in patients with amyotrophic lateral sclerosis. WALS Study Group. Western Amyotrophic Lateral Sclerosis Study Group.

We designed a phase II trial to evaluate the efficacy of gabapentin in slowing the rate of decline in muscle strength of patients with amyotrophic lateral sclerosis (ALS) and to assess safety and tolerability. Gabapentin (800 mg) or placebo was administered t.i.d. in a randomized, double-blinded, placebo-controlled, trial for 6 months. We enrolled 152 patients at eight sites in the United States. The primary outcome measure was the slope of the arm megascore, the average maximum voluntary isometric strength from eight arm muscles standardized against a reference ALS population. A secondary outcome measure was forced vital capacity. Slopes of arm megascores for patients on gabapentin were compared with slopes of those taking placebo using a two-way ANOVA. We observed a nonstatistically significant trend (p = 0.057-0.08) toward slower decline of arm strength in patients taking gabapentin compared with those taking placebo (mean difference 24%, median 37%). We observed no treatment effect on forced vital capacity. Gabapentin was well tolerated by patients with ALS. These results suggest that further studies of gabapentin in ALS are warranted.

Phase III randomized trial of gabapentin in patients with amyotrophic lateral sclerosis.

BACKGROUND: Preclinical and clinical studies of gabapentin in patients with ALS led the authors to undertake a phase III randomized clinical trial. METHODS: Patients were randomly assigned, in a double-blinded fashion, to receive oral gabapentin 3,600 mg or placebo daily for 9 months. The primary outcome measure was the average rate of decline in isometric arm muscle strength for those with two or more evaluations. RESULTS: Two hundred four patients enrolled, 196 had two or more evaluations, and 128 patients completed the study. The mean rate of decline of the arm muscle strength was not significantly different between the groups. Moreover, there was no beneficial effect upon the rate of decline of other secondary measures (vital capacity, survival, ALS functional rating scale, timed walking) nor was there any symptomatic benefit. In fact, analysis of the combined data from the phase II and III trials revealed a significantly more rapid decline of forced vital capacity in patients treated with gabapentin. CONCLUSION: These data provide no evidence of a beneficial effect of gabapentin on disease progression or symptoms in patients with ALS.

Regulation of VEGF-induced endothelial cell PAF synthesis: role of p42/44 MAPK, p38 MAPK and PI3K pathways.

1. Vascular endothelial growth factor (VEGF) is a potent angiogenic and inflammatory mediator. We have recently shown that this latter effect requires the activation of Flk-1 receptor and subsequent endothelial cell (EC) PAF synthesis. However, the intracellular events that regulate EC PAF synthesis upon Flk-1 stimulation by VEGF remain to be elucidated. 2. Using specific inhibitors and Western blot analysis, we herein report that in bovine aortic endothelial cells (BAEC), VEGF induces the synthesis of PAF through the cascade activation of Flk-1 receptor, phospholipase Cgamma (PLCgamma), protein kinase C (PKC) and p42/44 mitogen-activated protein kinases (MAPK). 3. Moreover, we demonstrate that VEGF-mediated PAF synthesis requires the activation of p38 MAPK, likely by directing the conversion of lyso-PAF to PAF. 4. Interestingly, we observed that VEGF also promoted the activation of the phosphatidyl inositol-3-phosphate kinase (PI3K) pathway, and that its blockade potentiated PAF synthesis following a VEGF treatment. Consequently, it appears that the PI3K pathway acts as a negative regulator of EC PAF synthesis. 5. Taken together, these results allow a better understanding of the intracellular events activated upon EC stimulation by VEGF, and shed a new light on the mechanisms by which VEGF induces PAF synthesis.

Isolation of a goldfish brain cytochrome P450 aromatase cDNA: mRNA expression during the seasonal cycle and after steroid treatment.

To investigate the molecular basis and physiological regulation of exceptionally high levels of aromatase (P450arom) activity in the brain of teleost fish, a 2927 bp P450arom cDNA encoding a 510 amino acid protein was isolated from a goldfish brain cDNA library. The brain-derived cDNA had 53% and 61-62% sequence identity when compared with human placental and fish ovarian P450arom forms, respectively, and higher homologies in conserved functional domains. Goldfish brain poly(A) RNA was translatable in vitro to a 56 kDa P450arom immunoprecipitation product. Northern blot analysis using the brain cDNA revealed a major 3.0 kb transcript of high abundance in brain (FB, forebrain > M/HB, mid/hindbrain), but no signal in ovary, testis or liver. P450arom mRNA varied seasonally in brain, with a peak at the onset of gonadal regrowth (February) that preceded the annual rise in enzyme levels and was 4-fold (FB) or 50-fold (M/HB) higher than during reproductive inactivity (July-December). Known markers of neurogenesis and estrogen action in brain (28S rRNA, beta-actin and beta-tubulin transcripts) each had unique seasonal patterns which differed from P450arom mRNA. In vivo steroid treatment showed that estrogen and aromatizable androgen increase FB and M/HB levels of P450arom mRNA 8- and 4-fold, respectively. P450arom mRNA in pituitary and retina had a different regulation. Southern analysis provided no evidence for multiple genes encoding the brain derived cDNA or for brain-specific gene amplification. Results imply that high accumulated levels of P450arom mRNA are the major determinant of high measured enzyme activity in goldfish brain, and that physiological regulation of mRNA expression in the natural environment is mediated by aromatization of androgen to estrogen.

Immunocytochemical and biochemical evidence for aromatase in neurons of the retina, optic tectum and retinotectal pathways in goldfish.

Using an animal model in which neural aromatase is apparently overexpressed (the goldfish, Carassius auratus) and an anti-human placental antibody which specifically crossreacts with goldfish brain aromatase, aromatase-immunoreactive neuronal cell bodies and fibers have been localized within the retina. These include a subset of horizontal cells, bipolar cells, and amacrine cells of the inner nuclear layer, some fibers of the outer and inner synaptic layers and certain cells of the ganglion cell layer; photoreceptors were never labeled. Some ganglion cell projections to the brain via the optic nerve and optic tract were aromatase-positive, as were small neurons of the stratum periventriculare (SPV) and fibers of two other strata of the optic tectum. Aromatase activity, as measured by [3H]androgen by tissue homogenates and cell cultures, confirmed the presence of aromatase in retina and in brain regions containing the optic tectum. This localization of the rate-limiting enzyme in estrogen biosynthesis suggests that neuroestrogen derived from circulating androgen m ay modulate transmission and integration of visual information important for reproduction in this species.

Molecular and cellular physiology of aromatase in the brain and retina.

Due to exceptionally high brain aromatase activity, teleost fish are advantageous for studying neural aromatase regulation, localization, and physiology. To determine the molecular mechanism of enhanced expression, we have isolated, cloned and sequenced a 3 kb full-length aromatase cDNA from a goldfish (Carassius auratus) brain library using a human placental aromatase cDNA as probe. The deduced sequence of goldfish aromatase is 510 amino acids (predicted Mw, 58 kDa) with 69% overall sequence similarity, when compared to human placental aromatase, and higher homologies in presumptive functional domains. A major 3 kb mRNA species was abundant in brain and low or non-detectable in non-neural tissues, reflecting the order of enzyme activities. To determine the cellular basis of high enzyme activity in goldfish brain, a human placental aromatase antibody was used to immunolocalize labeled cells. This antibody immunoprecipitated a single 56 kDa in vitro translation product of goldfish brain poly(A+)RNA and revealed discrete clusters of intensely stained neurons, processes, and terminals concentrated in, but not limited to, reproductive brain centers. Close proximity of aromatase- and androgen receptor-positive neurons in certain regions provides anatomic evidence of a functional relationship between direct and indirect pathways of neural androgen action. Aromatase-positive neurons and fibers formed interconnected networks in novel loci (e.g. retina-->optic tract-->optic tectum), and catalytic activity was confirmed biochemically in these tissues, indicating that neuroestrogen may have a role in visual input and integration. Availability of goldfish-specific nucleotide and antibody probes will facilitate further studies using this model.

Blunted pressor and intramuscular metabolic responses to voluntary isometric exercise in multiple sclerosis.

To test the hypothesis that a lower mean arterial pressure (MAP) response during voluntary isometric exercise in multiple sclerosis (MS) is related to a dampened muscle metabolic signal, 9 MS and 11 control subjects performed an isometric dorsiflexor contraction at 30% maximal voluntary contraction until target failure (endurance time). We made continuous and noninvasive measurements of heart rate and MAP (Finapres) and of intramuscular pH and P(i) (phosphorus magnetic resonance spectroscopy) in a subset of 6 MS and 10 control subjects. Endurance times and change in heart rate were similar in MS and control subjects. The decrease in pH and increase in P(i) were less throughout exercise in MS compared with control subjects, as was the change in MAP response. Differences in muscle strength accounted for some of the difference in MAP response between groups. Cardiovascular responses during Valsalva and cold pressor tests were similar in MS and control subjects, suggesting that the blunted MAP response during exercise in MS was not due to a generalized dysautonomia. The dampened metabolic response in MS subjects was not explained by inadequate central muscle activation. These data suggest that the blunted pressor response to exercise in MS subjects may be largely appropriate to a blunted muscle metabolic response and differences in contracting muscle mass.

Strength, skeletal muscle composition, and enzyme activity in multiple sclerosis.

This study examined functional, biochemical, and morphological characteristics of skeletal muscle in nine multiple sclerosis (MS) patients and eight healthy controls in an effort to ascertain whether intramuscular adaptations could account for excessive fatigue in this disease. Analyses of biopsies of the tibialis anterior muscle showed that there were fewer type I fibers (66 +/- 6 vs. 76 +/- 6%), and that fibers of all types were smaller (average downward arrow26%) and had lower succinic dehydrogenase (SDH; average downward arrow40%) and SDH/alpha-glycerol-phosphate dehydrogenase (GPDH) but not GPDH activities in MS vs. control subjects, suggesting that muscle in this disease is smaller and relies more on anaerobic than aerobic-oxidative energy supply than does muscle of healthy individuals. Maximal voluntary isometric force for dorsiflexion was associated with both average fiber cross-sectional area (r = 0.71, P = 0.005) and muscle fat-free cross-sectional area by magnetic resonance imaging (r = 0.80, P < 0. 001). Physical activity, assessed by accelerometer, was associated with average fiber SDH/GPDH (r = 0.78, P = 0.008). There was a tendency for symptomatic fatigue to be inversely associated with average fiber SDH activity (r = -0.57, P = 0.068). The results of this study suggest that the inherent characteristics of skeletal muscle fibers per se and of skeletal muscle as a whole are altered in the direction of disuse in MS. They also suggest that changes in skeletal muscle in MS may significantly affect function.

Mechanical ventilation in amyotrophic lateral sclerosis: a cross-cultural perspective.

Mechanical ventilation is known to be an effective means of relieving symptoms of chronic hypoventilation and prolonging life in patients with amyotrophic lateral sclerosis (ALS). Various methods of mechanical ventilation are available to patients with ALS. However, attitudes towards mechanical ventilation in ALS vary widely across different cultures, and even within a given medical system. This article describes differences and similarities between a North American, a European and a Japanese approach, based on the respective medical and cultural traditions. The common goal is to provide optimal palliative care to patients with ALS.

Quality of life for ventilator-dependent ALS patients and their caregivers.

Seven ventilator-dependent ALS patients and eleven caregivers were interviewed in order to assess the impact of ventilator-dependence on patients and their families. The ALS Care Database questionnaires were administered with special attention to components derived from the Health Status Survey (SF-12) and ALS Quality-of-Life Index (ALSQLI) as well as the ALS Patient Caregiver Form. Six patients had difficulty communicating and one patient was totally unable to communicate. Patients had maximal limitation of daily activities as measured by The ALS QLI, yet a self-reported satisfactory quality-of-life. Caregivers were heavily burdened and their outside activities were severely limited.

A preliminary evaluation of a prospective study of pulmonary function studies and symptoms of hypoventilation in ALS/MND patients.

There is still no consensus as to which physiologic marker should be used as a trigger for the initiation of non-invasive positive pressure ventilation (NPPV) in patients with amyotrophic lateral sclerosis (ALS). Current practice parameters recommend that the decision to begin treatment be based upon forced vital capacity (FVC) measurements. A prospective, randomized study was performed in 20 ALS patients who had an FVC of 70-100%. Patients received baseline assessments including: ALS functional rating scale-respiratory version (ALSFRS-R), pulmonary symptom scale, Short form 36 (SF-36), FVC%, maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and nocturnal oximetry. Patients were randomized to receive NPPV based upon nocturnal oximetry studies suggesting oxygen desaturation <90% for one cumulative minute ("early intervention") or a FVC <50% ("standard of care"). At enrollment, there was no significant correlation between FVC% and the ALSFRS-R, symptom score, MEP, MIP, or duration of nocturnal desaturation <90%. An increase in the vitality subscale of the SF-36 was demonstrated in 5/6 patients randomized to "early intervention" with NPPV. Our data indicate that FVC% correlates poorly with respiratory symptoms and suggests that MIP and nocturnal oximetry may be more sensitive measures of early respiratory insufficiency. In addition, intervention with NPPV earlier than our current standard of care may result in improved quality of life.

A placebo-controlled trial of gabapentin in spinal muscular atrophy.

OBJECTIVE: To evaluate the efficacy of gabapentin in increasing muscle strength of patients with spinal muscular atrophy (SMA). BACKGROUND: Preclinical data in experimental models of motor neuron disease suggest a neuroprotective effect of gabapentin. METHODS: Gabapentin (1200 mg), or placebo, was administered three times daily in a randomized, double-blind trial for 12 months. The primary outcome measure was the average percent change from baseline, based on the measurement of strength in four muscles (elbow flexion and hand grip bilaterally) for each patient. Drug efficacy was examined by comparing the percent change in strength for patients on drug vs. placebo. Secondary efficacy variables included: forced vital capacity (FVC), SMA functional rating scale (SMAFRS), and mini-Sickness Impact Profile (SIP). RESULTS: Eighty-four patients, with type II or III SMA, were enrolled at eight sites across the United States. There were no differences in baseline features. There was no difference between the placebo and drug groups in any outcome measure. CONCLUSIONS: This study demonstrates the feasibility of this trial design and provides data for the design of future clinical trials in SMA.

Cost effectiveness of recombinant human insulin-like growth factor I therapy in patients with ALS.

OBJECTIVE: Amyotrophic lateral sclerosis (ALS) is a fatal, degenerative neuromuscular disease characterised by a progressive loss of voluntary motor activity. Recombinant human insulin-like growth factor I (rhIGF-I) has been shown to be useful in treating ALS. The purpose of this study was to examine the cost effectiveness of rhIGF-I therapy in patients who have ALS. DESIGN: We performed a cost-effectiveness analysis from the societal perspective on 177 patients who received treatment with rhIGF-I or placebo in a North American randomised clinical trial. We estimated the incremental cost-effectiveness ratio of rhIGF-I using resource utilisation and functional status measurements from the clinical trial. Costs were estimated from 1996 US Medicare reimbursement schedules. Utility weights were elicited from ALS healthcare providers using the standard gamble technique. MAIN OUTCOME MEASURES AND RESULTS: The overall cost per quality-adjusted life-year (QALY) gained for rhIGF-I therapy compared with placebo was $US67,440. For the subgroups of patients who were progressing rapidly or were in earlier stages of disease at enrolment, rhIGF-I cost $US52,823 and $US43,197 per QALY gained, respectively. CONCLUSIONS: Treatment with rhIGF-I is most cost effective in ALS patients who are either in earlier stages of the disease or progressing rapidly. The cost effectiveness of rhIGF-I therapy compares favourably with treatments for other chronic progressive diseases.

Reduced MTR in the corticospinal tract and normal T2 in amyotrophic lateral sclerosis.

The objective of this study was to test the hypothesis that magnetization transfer ratios (MTR) are decreased in the corticospinal tract of patients with amyotrophic lateral sclerosis (ALS); to determine if T2 is increased in corticospinal tract or reduced in motor cortex in ALS; to determine if corticospinal tract MTR correlates with a clinical measure of motor neuron function in ALS. Ten ALS patients and 17 age-matched controls were studied. Double spin echo MRI and 3D gradient echo MRI with and without off-resonance saturation were acquired on each subject. 3D data sets were coregistered and resliced to match the spin echo data set. MTR was calculated for corticospinal and non-corticospinal tract white matter. T2 was calculated for corticospinal and non-corticospinal tract white matter, motor cortex and non-motor cortex. MTR was reduced by 2.6% (p < .02) in corticospinal, but not in non-corticospinal, tract white matter in ALS. There was no difference in T2 in any brain region. The correlation between a clinical measure of motor neuron function and corticospinal tract MTR was statistically significant. These findings are consistent with the known pathology in ALS and suggest that MTR is more sensitive than T2 for detecting involvement of the corticospinal tract. Quantitative MTR of the corticospinal tract may be a useful, objective marker of upper motor neuron pathology in ALS.