Significance of mesial temporal atrophy in relation to intracranial ictal and interictal stereo EEG abnormalities

We studied 31 consecutive patients with temporal and extratemporal epilepsy who underwent presurgical evaluation with stereotaxic depth EEG (SEEG) to assess the relationships between amygdalo-hippocampal (AM-HF) atrophy and the location of SEEG seizure onset and SEEG interictal abnormalities. Scalp EEG recordings with sphenoidal electrodes had shown bitemporal ictal or interictal epileptic abnormalities in all. Patients underwent high quality MRI scans, including MRI volumetric measurements of mesial temporal structures. None had foreign tissue lesions. The final conclusions of the SEEG investigation coincided with the lateralization obtained by MRI volumetric measurements in the eight patients who had significant unilateral atrophy of the amygdala, hippocampus or both (> 2 SD below the mean of controls). In these patients with unilateral atrophy, all or > 75% of clinical seizures originated from the atrophic side. The seven patients with bilateral, but significantly asymmetrical, mesial atrophy had bilateral seizure onsets with > 70% originating from the more atrophic side in four, from the less atrophic side in two, and without predominance in one. The one patient with severe bilateral symmetrical atrophy had seizures originating equally from both sides. Five patients had no atrophy on MRI, but depth electrodes revealed predominant unilateral ictal temporal onsets in four of them. There was no significant correlation between the frequency of SEEG interictal spikes and the amount of AM-HF atrophy. However, we found a significant correlation between the severity of SEEG background disturbance in AM and HF and the degree of atrophy of these structures. Patients with unilateral atrophy were more frequently free of seizures after surgery than those with bilateral or no atrophy (P < 0.05). We conclude that unilateral mesial atrophy predicts ipsilateral mesial SEEG seizure onset despite bitemporal extracranial EEG foci. However, in patients with significant bilateral mesial atrophy, SEEG seizures may originate from either side, even in the presence of significant asymmetry. Finally, the identification of unilateral mesial atrophy has prognostic importance.

Combined aerobic training and dichloroacetate improve exercise capacity and indices of aerobic metabolism in muscle cytochrome oxidase deficiency

There is no generally effective therapy for mitochondrial myopathies. In this study, we measured responses to combined aerobic training and oral dichloroacetate (DCA) therapy in a 25-year-old woman with a mitochondrial myopathy caused by cytochrome oxidase deficiency. The patient trained for 14 weeks, and DCA therapy was begun after 8 weeks. Independent indices of aerobic capacity and oxidative metabolism showed substantial improvement. Venous lactate concentrations at rest, and after a constant amount of work, decreased by approximately 50% after 8 weeks of aerobic training, and by more than 70% with the combination of training and DCA treatment. Heart rate at rest and after a constant amount of submaximal work decreased progressively. Aerobic capacity on a graded submaximal exercise test improved by 71% from baseline by the end of the treatment period. 31P magnetic resonance spectroscopy measurements of rate constants for recovery of muscle phosphocreatine increased 1.7-fold and metabolically active adenine diphosphate increased 2.8-fold after 8 weeks of training alone, and 4.5-fold and 23.0-fold after 14 weeks of training plus DCA treatment. Responses to the SF-36 Health Survey suggested a marked reduction in handicap. Thus, in this open study of a patient with cytochrome oxidase deficiency, a combination of aerobic training and DCA treatment resulted in substantial improvements in biochemical indices, exercise performance, and handicap. We conclude that exercise limitation in patients with mitochondrial myopathy may arise from effects of chronic deconditioning in addition to the effects of primary mitochondrial dysfunction and may be partially reversed by training and administration of DCA.

ADP recovery after a brief ischemic exercise in normal and diseased human muscle--a 31P MRS study

The pattern of cytosolic ADP recovery after exercise has not been fully characterized in human skeletal muscle. ADP recovery after brief, ischemic exercise was studied by 31phosphorus magnetic resonance spectroscopy in calf muscles of 33 normal control subjects, four patients with McArdle's disease and 13 patients with mitochondrial myopathy. In normal muscle, the half-time for the initial ADP decline was 0.18 +/- 0.07 min and was unaffected by the pH or the metabolic state at the end of exercise. ADP decreased to below rest values during the second min of recovery in 27 out of 33 control subjects. There was a significant (p < 0.001) linear correlation for both the size (r = 0.65) and duration (r = 0.64) of this ADP undershoot with intracellular pH. Phosphocreatine resynthesis continued during the ADP undershoot. ADP undershoot was also found in patients with mitochondrial diseases (in 11 out of 13), but not McArdle's disease (six patients). Thus ADP recovery follows a complex time course that is partly dependent on pH. Only the initial ADP recovery is independent of pH, which makes it suitable for comparative assessment of muscle mitochondrial function in vivo. As phosphocreatine recovery continues during the ADP undershoot, mitochondrial regulation must be different from that at the onset of recovery. These observations are consistent with variable, changing regulators of mitochondrial metabolism in human skeletal muscle.

Impairment of muscle mitochondrial oxidative metabolism in McArdles's disease

Impairment of muscle glycogenolysis in McArdle's disease (myophosphorylase deficiency) leads to exercise intolerance and exercise-induced myalgia. The pathophysiology of these symptoms is not entirely clear. We used phosphorus magnetic resonance spectroscopy to measure muscle phosphate metabolite concentrations and intracellular pH during brief ischemic exercise and in the period of aerobic metabolic recovery after exercise, with special attention to cytoplasmic adenosine 5'-diphosphate (ADP). In 5 patients with McArdle's disease, calculated muscle intracellular ADP concentrations at the beginning of recovery were higher than in normal control subjects (70-425 mmol/L, control mean: 73 +/- 40 mmol/L, P < 0.05). The half-time for intracellular ADP recovery after exercise, an index of maximal mitochondrial oxidative phosphorylation, was 0.16 +/- 0.07 in normal controls and was independent of metabolic state or intracellular pH. ADP recoveries were abnormally slow in all patients with McArdle's disease (range: 0.32-0.83 min, mean = 0.2 min, P < 0.0001). These results are indicative of a limitation in the rate of oxidative phosphorylation in muscle of patients with McArdle's disease, most likely due to impaired substrate delivery to mitochondria. This impairment of mitochondrial function may contribute to the exercise-related symptoms in McArdle's disease.

Assessment of lesion pathology in multiple sclerosis using quantitative MRI morphometry and magnetic resonance spectroscopy

Quantitative measurement of MRI-defined brain lesions can provide an index of the extent and activity of disease in multiple sclerosis patients. However, the relationships between these indices and clinical features are not well-understood. Heterogeneity of the pathological changes underlying MRI lesions may be an important factor determining the correlation between MRI lesion volumes and clinical measures. Recent studies have suggested that with magnetic resonance spectroscopy (MRS), it may be possible to define chemical changes that better reflect the pathological changes in multiple sclerosis. Here we report results of combined quantitative brain T2-weighted MRI lesion volume and proton MRS examinations that demonstrate heterogeneity of the chemical pathology underlying brain lesions in patients selected on the basis of similar clinical disability but differing with respect to the presence or absence of clinical relapses. We examined 29 patients with disease characterized by either clear relapses with at least partial remissions (RR) or secondary, chronic progression after an earlier history of a more relapsing and remitting course (SP). Total hemispheric lesion volume was greater (P < 0.04) in the RR (32.5 +/- 20.9 cm3) than in the SP (16.2 +/- 9.0 cm3) patients, despite the longer duration of disease in the latter group. Central brain N-acetyl aspartate: creatine (NAA:Cr) ratios were reduced relative to normal controls (4.0 +/- 0.3, n = 19) by similar amounts in the two patients groups (RR, 3.1 +/- 0.5; SP, 3.2 +/- 0.4; P < 0.0001). The ratio lesion volume:(NAA:Cr) was greater for the RR group (11.7 +/- 9.3 cm3) than for the SP group (5.4 +/- 3.3 cm3, P < 0.05), implying a greater average degree of axonal loss per unit lesion volume defined by MRI for subjects in the SP group or, alternatively, a greater proportion of lesions without axonal damage or loss in the RR group. Our results emphasize a limitation of using T2-weighted MRI lesion volume alone and suggest that combined analysis of MR-based chemical and imaging data might allow improved non-invasive assessment of lesion pathology in order to better understand its relationship to clinical features of multiple sclerosis.

Prevalence of endometriosis in rhesus (Macaca mulatta) monkeys ingesting PCB (Aroclor 1254): review and evaluation

A total of 80 menstruating rhesus monkeys (Macaca mulatta) were equally and randomly divided among groups receiving 0, 5, 20, 40, or 80 mu g of Aroclor 1254/kg body weight/day during a 6-year toxicological-reproduction study. During the first 3 years of the study, 4 of the treated monkeys became moribund and were euthanized; 3 had endometriosis. This finding suggested a possible link between the PCB treatment and the occurrence of endometriosis. However, neither a laparoscopic examination of the control and high-dose monkeys nor the necropsy data provided evidence for a possible link between the PCB treatment and the observed incidence (37% (6/16) of controls; 25% (16/64) of treated monkeys and/or the severity of the endometrial lesions. Additional clinical and historical data not contained in previous reports are presented to facilitate independent evaluation of the relationship between PCB ingestion and endometriosis. We conclude that the incidence and severity of the endometriosis lesions observed in the rhesus monkeys utilized in this study did not have any relationship with the dosages of Aroclor 1254 they ingested.

Accurate, noninvasive diagnosis of human brain tumors by using proton magnetic resonance spectroscopy

Although conventional proton magnetic resonance imaging has increased our ability to detect brain tumors, it has not enhanced to nearly the same degree our ability to diagnose tumor type. Proton magnetic resonance spectroscopy is a safe, noninvasive means of performing biochemical analysis in vivo. Using this technique, we characterized and classified tissue from normal brains, as well as tissue from the five most common types of adult supratentorial brain tumors. These six tissue types differed in their pattern across the six metabolites measured. 'Leaving-one-out' linear discriminant analyses based on these resonance profiles correctly classified 104 of 105 spectra, and, whereas conventional preoperative clinical diagnosis misclassified 20 of 91 tumors, the linear discriminant analysis approach missed only 1. Thus, we have found that a pattern-recognition analysis of the biochemical information obtained from proton magnetic resonance spectroscopy can enable accurate, noninvasive diagnosis of the most prevalent types of supratentorial brain tumors.

Chemical pathology of acute demyelinating lesions and its correlation with disability

We report the chemical pathological changes on magnetic resonance spectroscopic images of 4 patients, each of whom had a single large demyelinating plaque. The patients were followed from soon after the onset of the symptoms for a minimum of 7 months to a maximum of 3 1/2 years. We observed increases in the relative resonance intensities of choline-containing compounds, lactate, and myo-inositol inside the lesion acutely. Decreases in relative resonance intensities of N-acetylaspartate and creatine were seen both in and around the magnetic resonance imaging-detected lesions. In all patients neurological deficits improved and creatine, lactate, and myo-inositol resonance intensities normalized during the follow-up. Choline compounds recovered more slowly and were still abnormally high in 1 patient after 7 months. Partial recovery of the N-acetylaspartate resonance was seen for all patients. Evaluation of the relationships between indices of cerebral chemical pathology, brain lesion volumes, and functional disability showed highly significant negative correlations between N-acetylaspartate resonance intensities and both brain lesion volumes (r = -0.80, p < 0.0001) and clinical disability (r = -0.73, p < 0.0001). As N-acetylaspartate is localized solely in neurons in the adult central nervous system, our results suggest that neuronal dysfunction may be a proximate mechanism of disability even in inflammatory disorders primarily affecting myelin and oligodendroglial cells.

Association of cerebral dysgenesis and lactic acidemia with X-linked PDH E1 alpha subunit mutations in females

We describe an infant girl who presented at age 4 1/2 months with developmental delay, infantile spasms, hypotonia, and elevated lactate levels in the blood and cerebrospinal fluid. She had minor dysmorphic features. Muscle phosphorus magnetic resonance spectroscopy demonstrated reduced phosphocreatine and increased inorganic phosphate, suggesting a defect in oxidative energy metabolism. Pyruvate dehydrogenase activity in cultured fibroblasts was reduced (0.35 nmol/mg mitochondrial protein/min; controls 0.7-1.1 nmol/mg mitochondrial protein/min). Immunoblotting demonstrated a reduced amount of pyruvate dehydrogenase (PDH) E1 alpha immunoreactive protein with normal amounts of E2 protein. Single-strand conformational polymorphism analysis of E1 alpha cDNA prepared from fibroblasts disclosed an abnormal migration pattern, suggesting heterozygosity for a mutant allele. Dideoxy-fingerprinting of PCR-amplified genomic DNA was used to localize the mutation to exon 10. Direct sequencing demonstrated a novel 13-bp insertion mutation that would lead to premature termination of the protein product. This study further extends the allelic heterogeneity underlying PDH deficiency. The demonstration of bioenergetic abnormalities in muscle emphasizes that hypotonia in PDH deficiency may have combined peripheral and central etiologies. The results further suggest that the association of cerebral dysgenesis with lactic acidemia in females may be a useful clue to PDH deficiency.

Frequency and characteristics of dual pathology in patients with lesional epilepsy

We studied 167 patients who had identifiable lesions and temporal or extratemporal partial epilepsy. Pathology included neuronal migration disorders (NMDs) (48), low-grade tumors (52), vascular malformations (34), porencephalic cysts (16), and gliotic lesions as a result of cerebral insults early in life (17). MRI volumetric studies using thin (1.5- or 3-mm) coronal images were performed in all patients and in 44 age-matched normal controls. An atrophic hippocampal formation (HF), indicating dual pathology, was present in 25 patients (15%). Abnormal HF volumes were present in those with lesions involving temporal (17%) but also extratemporal (14%) areas. Age at onset and duration of epilepsy did not influence the presence of HF atrophy. However, febrile seizures in early childhood were more frequently, although not exclusively, found in patients with hippocampal atrophy. The frequency of hippocampal atrophy in our patients with low-grade tumors (2%) and vascular lesions (9%) was low. Dual pathology was far more common in patients with NMDs (25%), porencephalic cysts (31%), and reactive gliosis (23.5%). Some structural lesions, such as NMDs, are more likely to be associated with hippocampal atrophy, independent of the distance of the lesion from the HF. In other types of lesions, such as vascular malformations, dual pathology was found when the lesion was close to the HF. A common pathogenic mechanism during pre- or perinatal development may explain the occurrence of concomitant mesial temporal sclerosis and other structural lesions because of either (1) associated developmental abnormalities or (2) predisposition to prolonged febrile convulsions.(ABSTRACT TRUNCATED AT 250 WORDS)

Reversible decreases in N-acetylaspartate after acute brain injury

N-Acetylaspartate (NAA), which constitutes the major proportion of the dominant resonance in proton MR spectra of brain, is localized in mature brain exclusively in neurons and neuronal processes. A decrease in NAA has been observed in many cerebral pathologies and has usually been interpreted as an index of irreversible neuronal loss. The authors report a follow-up study of six patients with acute brain damage (four from demyelinating lesion and two from mitochondrial encephalopathy with lactic acidosis and stroke-like episodes [MELAS]). All patients underwent serial MR spectroscopy examinations. The four patients with acute demyelinating lesions initially showed decreases in NAA in the centers of the lesions that ranged between 34-72% of values from homologous brain volumes in the other hemisphere. All four patients subsequently showed substantial recovery of NAA as their clinical status improved. The two patients with MELAS syndrome had large decreases of NAA signal (50% and 20% of normal values, respectively) from their occipital lobe lesions during the acute stroke-like episodes. After the acute phase of the illness a progressive increase of NAA in the same volumes was seen in both patients (to 76% and 60% of normal values, respectively). These results demonstrate that significant recovery of NAA can occur after acute brain damage. The potential contribution of reversible neuronal dysfunction (as well as neuronal loss) must be considered in the interpretation of decreases in the NAA resonance associated with acute brain pathology.

Postmortem tissue levels of polychlorinated biphenyls in female rhesus monkeys after more than six years of daily dosing with Aroclor 1254 and in their non-dosed offspring

Polychlorinated biphenyl (PCBs) analyses were made on prenecropsy blood samples and postmortem adipose, liver, kidney, and brain tissues from female rhesus monkeys fed a daily dose of 0, 5, 20, 40, or 80 micrograms Aroclor 1254/kg body weight for approximately 6 years. During this time, the females were bred with non-dosed males. All resulting offspring were nursed for 22 weeks and fed no additional PCBs until they were necropsied at approximately 120 weeks after birth. PCBs were also measured in necropsied infant tissues to determine PCB levels due to intake of PCB-contaminated milk from the dosed dams, in addition to in utero exposure. Polychlorinated biphenyl levels in all tissues of the adult monkeys increased with their dosage. The highest PCB levels were found in adipose tissue and the lowest levels were found in the brain. Polychlorinated biphenyl residues in the cortex of the kidney were lower than in the medulla, while in the brain no appreciable differences were observed between the occipital and frontal lobes. Necropsy tissues of infants from dosed dams contained more PCBs than those nursed by controls, but less than tissues from stillborn infants. Although no differences were observed between PCB tissue levels from monkeys having offspring and those having no offspring, those having a stillborn infant had higher PCB levels in their tissues than those with a viable infant. Similarly, monkeys that were euthanized because of poor health had higher PCB levels in their tissues than those necropsied at the conclusion of the study and showed a dramatic shift from tetra- and hexachlorobiphenyls to penta- and heptachlorobiphenyls in their tissues. The PCB distribution pattern in tissues from a dosed mother/infant pair differed considerably. A larger percentage of heptachlorobiphenyls was found in the infant than in its dam. The adipose/blood PCB ratio in the adult monkeys remained remarkably constant.

Female rhesus monkeys dosed with Aroclor 1254: analysis of polychlorinated biphenyl congeners in dam's milk and in the blood of dams and their offspring before, during, and after gestation

Specific polychlorinated biphenyl (PCB) congeners were measured before, during, and after gestation in the blood of rhesus monkeys, as well as in their milk and in the blood of their infants during lactation, as part of a long-term feeding study to evaluate the toxicology of Aroclor 1254 on pre- and postnatal development of infant monkeys. During gestation a considerable shift from the higher to lower chlorinated biphenyls in the blood was observed in both dosed and nondosed animals. The contribution of penta- and hexachlorobiphenyls in the milk slightly increased with higher dosage. In addition, the percentages of 2,2'3,4,5'-,2,2',4,5,5'-, and 2,3,3',4',6-pentachlorobiphenyls were remarkably lower in the milk of dosed dams than in the originally ingested Aroclor 1254. PCB congener levels in infant blood increased during the lactation period but immediately decreased upon weaning. The lower chlorinated biphenyls virtually disappeared from infant blood after 16 weeks of nursing. Some correlations were observed between PCB congener levels in mother and infant and the congener ratios calculated.

Mitochondrial disease. Pulmonary function, exercise performance, and blood lactate levels

Mitochondrial diseases are a heterogeneous group of disorders in which it has been suggested that genetic defects in oxidative phosphorylation lead to specific alterations in exercise performance and lactate metabolism during exercise. To investigate this possibility, we evaluated pulmonary function tests, incremental exercise testing, and serial blood lactate levels in a group of subjects with mitochondrial disease (M) and compared them with a group of patients with nonmitochondrial (N) myopathies and healthy subjects (H). The two groups were demographically comparable and had no significant differences in pulmonary function. Both groups showed similar degrees of reduced exercise tolerance compared with a group of healthy subjects (M: 61.08% predicted VO2max +/- 19.58 SD, n = 13; N: 62.14 +/- 28.89, n = 7; H: 115.17 +/- 19.35, n = 12; p < 0.001). The mitochondrial disease group more frequently showed abnormalities in cardiac response to exercise than did the nonmitochondrial myopathy subjects (M: 12/13, N: 3/7, H: 3/12, p = 0.002). Minute ventilation greater than predicted occurred with similar frequency in both groups. Although resting lactate level was increased in some subjects with mitochondrial myopathy compared with disease controls, there were no differences between groups for peak venous lactate level normalized for oxygen uptake or the rate of lactate clearance. These findings, while confirming the presence of some specific abnormalities in mitochondrial disease, are against the notion that exercise limitation in this condition directly results from specific abnormalities in oxidative metabolism.

Toxicological consequences of aroclor 1254 ingestion by female rhesus (Macaca mulatta) monkeys. Part 2. Reproduction and infant findings

A group of 80 menstruating rhesus (Macaca mulatta) monkeys were randomly allocated to four similar test rooms (20 monkeys/room) and then randomly allocated within each room to one of five dose groups (four females/dose group/room). Each day, the monkeys self-ingested capsules containing doses of 0, 5, 20, 40 or 80 micrograms Aroclor 1254/kg body weight. After 25 months of continuous dosing, approximately 90% of the treated females had attained a qualitative pharmacokinetic steady state with respect to the concentration of polychlorinated biphenyl (PCB) in their adipose tissue. Commencing on test month 37, each female was paired with an untreated male until either an impregnation occurred or the 29-month breeding phase of the study was completed. The females continued to receive their daily test dose during mating and gestation. To preclude an infant ingesting the mother's dosing capsule, dosing of the dam was discontinued when a nursing infant was approximately 7 wk old. Treatment was restarted when the infant was weaned at 22 wk of age. At parturition, and every 4 wk until weaning, milk and blood samples were obtained from the dam and a blood sample was obtained from the infant for PCB analysis. When the infant was 20 wk old, immunological testing was initiated and an adipose sample was obtained from the infant and dam for PCB analysis. Subsequently, further adipose and blood samples were obtained from the infant and blood specimens were obtained from the dam for PCB analysis. Concurrently, each infant was subjected to anthropometric measurements and detailed clinical examinations until it was approximately 122 wk old. At 122 wk some of the control and all of the treated infants were killed humanely and autopsied. A statistical analysis of the reproduction data provided evidence for a significant decreasing dose-related trend in conception rates and a significant increasing dose-related trend in foetal mortality. Several comparisons between impregnated and non-impregnated females did not implicate 'age' as a confounding factor regarding these results. The major findings with the infants involved some immunological test differences and mild clinical manifestations of PCB ingestion.

Short-term dichloroacetate treatment improves indices of cerebral metabolism in patients with mitochondrial disorders

We performed a short-term, double-blind, placebo-controlled, crossover trial of sodium dichloroacetate (DCA) therapy in 11 patients affected by various primary mitochondrial disorders. Independent measures of oxidative metabolism (venous blood metabolites, exercise testing, phosphorus magnetic resonance [MR] spectroscopy of muscle, and proton MR spectroscopy of brain) were used in order to monitor metabolic responses to the drug. One week of DCA treatment produced significant decreases (p < 0.05) in blood lactate, pyruvate, and alanine at rest and after bicycle exercise. Proton MR spectra collected from a supraventricular volume of interest in brain of seven of 11 patients also showed significant changes. Brain lactate/creatine ratio decreased by 42% during DCA treatment (p < 0.05). Brain choline/creatine ratio (which is low in patients with myelinopathies) increased by 18% (p < 0.01) after therapy. N-Acetylaspartate/creatine ratio (an index of neuronal damage or loss) increased by 8% after treatment (p < 0.05). Proton MR spectra collected in two of 11 patients from a volume of interest including the basal ganglia showed similar results (decrease of 36.6% in lactate/creatine; increases of 16% in choline/creatine and 4.5% in N-acetylaspartate/creatine). Phosphorus MR spectroscopy of muscle and self-assessed clinical disability were unchanged. Our study indicates that short-term DCA treatment not only lowers blood lactate but also improves indices of both brain oxidative metabolism and neuronal and glial density or function.

Imaging of axonal damage in vivo in Rasmussen's syndrome

We obtained magnetic resonance spectroscopic images (MRSIs) in three patients with Rasmussen's syndrome. The relative resonance intensity of N-acetylaspartate (NAA) to creatine (NAA:Cr), an index of neuronal loss or damage, was determined for various regions within the brain, and the affected:unaffected hemisphere asymmetry ratio was determined. All three patients had decreased relative NAA signal intensity over the entire affected hemisphere. The decrease in NAA:Cr involved cortex and white matter, was most prominent in the anterior periventricular region, and showed a tendency to be worse in patients with longer duration of disease. 1 year follow-up MRSI showed further reduction of the relative NAA signal in all patients, indicating progression of the disease. All patients were free of seizures for at least 48 h before the first MRSI, but two of them had epilepsia partialis continua (EPC) during the follow-up examination. There was no significant increase of the lactate resonance intensity, except in the two MRSIs performed during EPC. This indicates that lactate accumulation results from repetitive seizures rather than from the disease process itself. The spatial distribution of the metabolic abnormality on MRSI was more widespread than that of the structural abnormality on MRI. The relative NAA resonance intensity was not reduced in the contralateral hemisphere. Our findings indicate that MRSI can identify and quantify neuronal damage and loss throughout the affected hemisphere of patients with Rasmussen's syndrome, including areas that appear normal on conventional MRI.

Glutaric acidemia type II: neuroimaging and spectroscopy evidence for developmental encephalomyopathy

Glutaric acidemia type II is associated with neonatal hypoketotic hypoglycemia, metabolic acidosis, profound hypotonia, progressive cardiomyopathy, and early death. Deficiency of either electron transfer flavoprotein or electron transport flavoprotein:ubiquinone oxidoreductase leads to intramitochondrial accumulation of metabolites of compounds oxidized by enzymes that transfer electrons to flavoprotein. No detailed results of antemortem neuroimaging or magnetic resonance spectroscopy have been described previously. We investigated a patient with typical neonatal onset glutaric acidemia type II without obvious dysmorphogenesis or renal malformations. Cranial tomographic scan revealed hypoplastic temporal lobes and marked widening of the sylvian fissures ("bat-wing" appearance). Cranial magnetic resonance imaging documented underdeveloped frontal and temporal lobes with delayed myelination and hypoplasia of the corpus callosum. 31P-Magnetic resonance spectroscopy of muscle was grossly abnormal with a very low energy state consistent with mitochondrial dysfunction. 1H-Magnetic resonance spectroscopy of brain revealed elevated intracerebral lactate concentration and abnormally high choline/creatine ratio suggestive of dysmyelination. These findings constitute the first in vivo evidence of a developmental encephalomyopathy in glutaric acidemia type II.

Neuroimaging in multiple sclerosis

Neuroimaging in multiple sclerosis is now dominated by MR imaging. This article will focus primarily on conventional MR imaging studies in multiple sclerosis, but will also discuss briefly some of the more recent advances related to MR imaging. Fast spin-echo imaging, fluid attenuated inversion recovery MR studies, three-dimensional volumetric studies, magnetization transfer, and magnetic resonance spectroscopy as it applies to multiple sclerosis are examined.

The elimination and estimated half-lives of specific polychlorinated biphenyl congeners from the blood of female monkeys after discontinuation of daily dosing with Aroclor 1254

The levels of thirty polychlorinated biphenyl congeners in the blood of female rhesus monkeys, previously dosed with Aroclor 1254 for over six years, were monitored every two weeks during the first year and monthly during the subsequent two years after dosing was discontinued. Both blood lipid and polychlorinated biphenyl congener levels generally declined during this post dosing period. The percent distribution of the PCB congeners during the post dosing period remained relatively constant with more than half of all polychlorinated biphenyls consisting of the mono-orthochlorine substituted biphenyls. The contribution of the mono-orthochlorine substituted biphenyls was significantly different for one out of three monkeys in two of the three dose groups, during the post dosing period. Half-life, estimations for nine of the congeners ranged from 0.3-7.6 years.

Proton magnetic resonance spectroscopic images and MRI volumetric studies for lateralization of temporal lobe epilepsy

We obtained 2D magnetic resonance (MR) spectroscopic images (MRSI) and MRI volumetric measurements (MRIV) of amygdala and hippocampus in 30 consecutive patients with temporal lobe epilepsy (TLE) being evaluated for surgical treatment. Both MRSI and MRIV lateralization showed good agreement with the current gold standard of clinical-EEG lateralization. Each exam separately correctly lateralized 25 out of 30 patients with no false lateralization. Combining both exams, lateralization could be achieved in 28 out of 30 patients. The two patients with no significant asymmetry had bitemporal EEG abnormalities, and bilateral damage on both MRIV and MRSI. There was a good correlation between the magnitude of the MRSI and MRIV asymmetry (Pearson coefficient = 0.83; p < .0001). Both MRSI and MRIV were normal in our patients with seizures originating outside the temporal lobes. Both MRIV and MRSI can lateralize TLE in 83% of patients. Combination of the two modalities allows lateralization in 93% of patients. Patients who cannot be lateralized generally have symmetrical bitemporal abnormalities; they are not incorrectly lateralized. The structural and chemical pathologic abnormalities seen in TLE seem to be associated with the seizure focus, and may be as, or even more, reliable than a few recorded seizures in predicting the side from which most seizures originate.

Somaclonal variation in watercress for resistance to crook root disease

Watercress (Rorippa nasturtium-aquaticum) shoots were regenerated from callus initiated from petioles on a range of media. The best coefficient of regeneration was obtained when callus was induced on a medium containing 0.25 mgl(-1) thidiazuron and 0.05 mgl{si-1} 2,4-D, followed by regeneration on 0.25 mgl(-1) thidiazuron. Plants were then screened for resistance to crook root disease of watercress in a laboratory screening test which revealed significant somaclonal variation between the controls and some of the somaclones.

Cerebral dysgenesis and lactic acidemia: an MRI/MRS phenotype associated with pyruvate dehydrogenase deficiency

Pyruvate dehydrogenase complex (PDHC) is an intramitochondrial multienzyme complex essential for the aerobic oxidation of glucose. The majority of patients with PDHC deficiency have abnormalities in the major catalytic and regulatory subunit, E1 alpha, which is encoded on the X chromosome. The clinical spectrum of PDHC deficiency is heterogeneous, particularly in heterozygous females, and diagnosis may be difficult. Three affected infant girls with PDHC deficiency were investigated. All had dysmorphic features, microcephaly with profound global developmental delay, and hypotonia. Systemic acidosis was absent, although serum lactate and pyruvate were abnormally elevated. Magnetic resonance imaging revealed hypoplasia of the corpus callosum in all patients. Proton magnetic resonance spectroscopy of brain revealed large increases in relative signal intensities for lactic acid and decreases in the relative signal intensities of N-acetylaspartate, a marker of neuronal damage or less. Phosphorus MRS of muscle revealed abnormally low phosphorylation potentials for all these patients, although the degree of abnormality was variable and not directly correlated with the amount of brain lactate. It is proposed that cerebral dysgenesis and cerebral lactic acidemia as shown by magnetic resonance imaging and proton magnetic resonance spectroscopy are useful diagnostic clues to PDHC deficiency, particularly in females in whom variable patterns of X-inactivation reduce sensitivity of laboratory diagnosis based on the biochemical studies of peripheral tissues. In addition, muscle bioenergetic abnormalities in conjunction with CNS dysfunction may contribute to profound hypotonia in this disorder.

Detection of cortical neuron loss in motor neuron disease by proton magnetic resonance spectroscopic imaging in vivo

We performed proton magnetic resonance spectroscopic imaging (1H-MRSI) in patients with motor neuron disease (MND) to evaluate the distribution and extent of cortical neuron damage or loss as reflected by decreased N-acetyl (NA) to creatine (Cr) resonance intensity ratios. We examined premotor (superior frontal gyrus), primary motor (precentral gyrus), primary sensory (postcentral gyrus), and parietal (superior parietal gyrus/precuneus) neocortical regions of 12 patients with MND and six normal control subjects. Patients with MND were representative of three syndromes: amyotrophic lateral sclerosis (ALS) with definite lower motor neuron and upper motor neuron signs, MND with probable upper motor neuron signs (PUMNS), and progressive spinal muscular atrophy (PSMA) with lower motor neuron signs only. Compared with healthy controls, ALS patients had a significant decrease in NA/Cr resonance intensity ratios, most prominently in the primary motor cortex (p < 0.001) but also, to varying degrees, in primary sensory (p < 0.01), posterior premotor, and parietal (p < 0.05) regions. Patients classified as ALS-PUMNS showed less prominent reduction in NA/Cr ratios in the same regions; patients with PSMA had normal cortical NA/Cr ratios. Sequential studies in one patient suggested that 1H-MRSI could document progression of the NA/Cr abnormality. Decreased NA/Cr ratios on 1H-MRSI provide an index of cortical motor neuron loss and/or dysfunction in MND patients. Clinical applications of 1H-MRSI could include documenting the extent of upper motor neuron involvement, aiding diagnosis of syndromes presenting with an ALS-like picture, and monitoring disease progression.

Use of proton magnetic resonance spectroscopy for monitoring disease progression in multiple sclerosis

Decreases in brain N-acetylaspartate are associated with neuronal loss or dysfunction. We report a longitudinal study in which changes in the N-acetylaspartate to creatine resonance intensity ratio measured by brain proton magnetic resonance spectroscopy were used to follow the progression of brain pathology in 7 patients with multiple sclerosis over an 18-month period. Four of the patients had a history of recurrent relapses and 3 had a secondary progressive course. All had clinical and magnetic resonance imaging evidence of persistent neurological abnormalities. At 6-month intervals proton magnetic resonance spectra were obtained and the N-acetylaspartate-creatine ratio was determined for each patient. The volumes of hyperintense signal from lesions on conventional magnetic resonance images and the Kurtzke Expanded Disability Status Scale scores were determined concurrently. At the onset of the study, the N-acetylaspartate-creatine ratio was significantly (p < 0.05) lower in the central brain volumes from the patients than in 13 normal control subjects. At 12 and 18 months of follow-up, the ratio had decreased further in all patients (p < 0.05), consistent with progressive accumulation of neuronal damage. In contrast to magnetic resonance spectra data, changes in lesion volume on magnetic resonance images or disability status did not reach significance over this period. Subgroup analysis showed that changes (increases or decreases) in the N-acetylaspartate-creatine ratio between consecutive 6-month examinations correlated significantly (r = -0.74, p < 0.005) with changes in lesion volume on magnetic resonance images in patients with a history of relapses.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnetic resonance spectroscopy in Niemann-Pick disease type C: correlation with diagnosis and clinical response to cholestyramine and lovastatin

Niemann-Pick type C is an autosomal-recessive, neurovisceral storage disorder that results from defective cholesterol esterification. Cholesterol-lowering agents have been demonstrated to decrease hepatic lipids in Niemann-Pick type C patients. The objective was to determine the effects of cholesterol-lowering agents on neurologic features and to develop a noninvasive method of monitoring clinical response. A 9-month-old boy with progressive hepatosplenomegaly and neurodevelopmental delay was studied. Water-suppressed proton magnetic resonance spectra from a supraventricular volume of central white and gray matter revealed an abnormal lipid signal. The patient was treated with cholesterol-lowering agents (i.e., cholestyramine, lovastatin). Repeat standardized neurodevelopmental assessments (Peabody and Griffith scales) at 13 and 19 months were normal and magnetic resonance spectra no longer detected the previously observed lipid resonance. Early treatment of Niemann-Pick type C patients with cholesterol-lowering agents appeared to have short-term beneficial effects. Magnetic resonance spectra provided a noninvasive means of monitoring CNS response.

Normative hematologic and serum biochemical values for adult and infant rhesus monkeys (Macaca mulatta) in a controlled laboratory environment

During the conduct of a long-term toxicity/reproduction study using rhesus monkeys (Macaca mulatta), periodic hematologic and serum biochemical analyses were undertaken on blood obtained from 15 untreated (vehicle control) adult female monkeys over a period of 3 yr, 20 untreated adult males over a period of 6 yr, and 9 infants (5 male, 4 female, whose dams were the vehicle control females) from 12 wk through 2 yr of age. All samples were obtained by femoral puncture. To facilitate handling, ketamine hydrochloride (Ket.HCl) was administered to the males, and for some of the later infant samplings. Complete blood cell counts were performed using electronic cell counters, while reticulocyte counts and leukocyte differentials were assessed manually. The serum biochemistry analyses were performed with automated analyzers. These data were obtained as part of a health monitoring program, with medians and 2.5 to 97.5 percentiles for each parameter indicated. Some monitored parameters were found to be affected by the type of equipment used and by the use of Ket.HCl.

Lateralization of temporal lobe epilepsy based on regional metabolic abnormalities in proton magnetic resonance spectroscopic images

Magnetic resonance spectroscopic imaging (MRSI) is capable of determining the spatial distribution in vivo of cerebral metabolites, including N-acetylaspartate (NAA), a compound found only in neurons. We used this technique in 10 patients with temporal lobe epilepsy (TLE) to determine the location of maximal neuronal/axonal loss or damage and to evaluate the potential of MRSI for presurgical lateralization. Asymmetry of the relative resonance intensity of NAA to creatine was determined for mid and posterior regions of the temporal lobes defined anatomically and also for "metabolic lesions" defined as the regions of maximal abnormality on MRSI. MRSI revealed decreased relative signal intensity in at least one temporal lobe of all patients. Two patients had a widespread reduction in NAA in both temporal lobes. The region of maximal abnormality was usually in the posterior temporal lobe but sometimes in the mid temporal lobe. The side of lowest NAA was ipsilateral to the clinical electroencephalographic lateralization in all patients. Lateralization based on NAA to creatine correlated with the atrophy of amygdala and hippocampus in 8 patients who showed this on magnetic resonance imaging volumetric measurements. MRSI can demonstrate regional neuronal loss or damage that correlates with clinical electroencephalographic and structural lateralization in temporal lobe epilepsy. The ability to identify a region of maximal metabolic abnormality on spectroscopic images may confer greater sensitivity than that available from single voxel methods. The maximal metabolic abnormality may not be located in a voxel defined a priori, and based on anatomical considerations, without knowledge of the distribution of the metabolic abnormality.

Determination of polychlorinated biphenyls in postpartum blood, adipose tissue, and milk from female rhesus monkeys and their offspring after prolonged dosing with Aroclor 1254

Analytical and quality control procedures are described for the determination of polychlorinated biphenyls in blood, adipose tissue, and milk from dosed female monkeys and their offspring, as part of a study to measure the toxicological effect of Aroclor 1254 on the pre- and postnatal development of fetus and infant, respectively. Recoveries of polychlorinated biphenyls from fortified blood, fat, and milk of monkeys ranged from 81 to 96%, whereas recoveries from fortified corn oil, used to evaluate routine analysis, ranged from 94 to 108%. The coefficient of variation for triplicate analyses of lipids and polychlorinated biphenyls in blood or adipose tissue or both was less than 10%. Polychlorinated biphenyl levels in blood, milk, and fat rose with increasing dosage. After weaning, when the infants were no longer exposed to polychlorinated biphenyls, their blood levels declined rapidly and approached maternal levels within 40-50 weeks. Approximately 100 weeks after weaning, polychlorinated biphenyl levels in adipose tissue of infants from treated dams reached the background levels of those in the control group.

Proton MR spectroscopic characterization of differences in regional brain metabolic abnormalities in mitochondrial encephalomyopathies

Localized brain proton MR spectra were acquired from patients with different mitochondrial encephalomyopathies (myoclonus epilepsy with ragged-red fibers [MERRF], Kearns-Sayre syndrome [KSS], and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes [MELAS]). The regional brain metabolic abnormalities in patients with these syndromes showed different features consistent with the distinct phenotypes. In MERRF, only one of four patients showed an increase in the lactate/creatine resonance intensity ratio (an index of impairment of oxidative metabolism) in spectra from central (supraventricular) or occipital brain volumes, and this was small. There were significant decreases in N-acetylaspartate/creatine (a measure of neuronal loss or dysfunction) in central cerebral volumes of demented patients and, more prominently, in occipital volumes. In the one patient in whom it was studied, the cerebellum also showed a decreased N-acetylaspartate/creatine. Spectra from two patients with KSS both showed large (four- to sevenfold) increases in lactate/creatine and large decreases in N-acetylaspartate/creatine in central brain volumes. Yet another pattern of regional metabolic abnormality was present in the MELAS syndrome, where proton spectroscopic imaging demonstrated focal localization of abnormally increased lactate/creatine and decreased N-acetylaspartate/creatine to the regions of the stroke-like lesions on conventional MR images. Serial studies emphasized that the regional metabolic abnormalities in MELAS are highly variable as the stroke-like lesions appear and evolve.

Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaca mulatta) monkeys. Part 1A. Prebreeding phase: clinical health findings

A group of 80 menstruating rhesus (Macaca mulatta) monkeys, with an average estimated age of 11.1 +/- 4.1 yr SD, were first randomly allocated to four similar test rooms (20 monkeys/room) and then randomly allocated to one of the five dose groups (four females/dose group/room). Each day, the females self-ingested capsules containing doses of 0, 5, 20, 40 or 80 micrograms Aroclor 1254/kg body weight. After 25 months of daily dosing, approximately 90% of the treated females attained a qualitative pharmacokinetic steady state with respect to the concentration of polychlorinated biphenyl in their adipose tissue. The test monkeys were monitored daily for health and menstrual status, as well as feed and water consumption. On a weekly basis, each female's body weight was determined and a detailed clinical examination was conducted. Minor treatment effects included a slight, but not statistically significant, decrease in feed and water consumption as well as a decreased feed conversion ratio and a slight increase in the duration of menses. Statistically significant, dose-related treatment effects included inflammation and/or prominence of the tarsal (Meibomian) glands, eye exudate, and various finger and toe nail changes. These results were found at doses lower than those previously reported for non-human primates.

Toxicological consequences of Aroclor 1254 ingestion by female rhesus (Macaca mulatta) monkeys. Part 1B. Prebreeding phase: clinical and analytical laboratory findings

A group of 80 menstruating rhesus (Macaca mulatta) monkeys, with an average estimated age of 11.1 +/- 4.1 yr SD were first randomly allocated to four similar test rooms (20 monkeys/room), and then randomly allocated to one of five dose groups (four females/dose group/room). Each day, the monkeys self-ingested capsules containing doses of 0, 5, 20, 40 or 80 micrograms Aroclor 1254/kg body weight. After 25 months of daily dosing, approximately 90% of the treated females attained a qualitative pharmacokinetic steady state with respect to the concentration of polychlorinated biphenyl (PCB) in their adipose tissue. Subsequently, oestrogen and progesterone concentrations in serum were determined for one complete oestrous cycle and various immunological tests were conducted, while the monkeys continued to receive their daily dose of PCB. During the prebreeding phase of the study, blood for clinical and analytical monitoring including haematology, serum biochemistry, serum hydrocortisone, serum proteins (alpha 1, alpha 2, beta and gamma-globulins), serum immunoglobulins (A, G and M) and thyroid variables (thyroxine/triiodothyronine (T3) uptake ratio, percentage T3 uptake and free thyroxine index), were obtained monthly, as were specimens to ascertain the concentration of PCB in the blood, adipose tissue and faeces. Major findings among treated monkeys included the following: changes in haematology (decreased erythrocyte count, haematocrit, reticulocyte count, and mean platelet volume), serum biochemistry (decreased cholesterol and total bilirubin), immunotoxicity (decreased antibody production to sheep red blood cells and alterations in the percentage of T helper and T suppressor cells) and pathology (the number of regions of sebaceous gland lobules per unit of histological length was significantly reduced). These effects were observed at PCB doses lower than those previously reported for non-human primates.

Evidence for mitochondrial dysfunction in patients with alternating hemiplegia of childhood

Phosphorus magnetic resonance spectra of resting muscle were obtained from 4 patients with alternating hemiplegia of childhood. All patients had abnormally high resonance intensities from inorganic phosphate and an abnormally low calculated cytosolic phosphorylation potential. Two of the 4 patients had abnormally low resonance intensities from phosphocreatine and an abnormally high calculated cytosolic free adenosine diphosphate concentration. These abnormalities are indicative of mitochondrial dysfunction. The combination of a central nervous system disorder and evidence of mitochondrial dysfunction in muscle suggests that alternating hemiplegia of childhood may represent a previously unrecognized phenotype of mitochondrial disease.

Coenzyme Q10 with multiple vitamins is generally ineffective in treatment of mitochondrial disease

We followed 16 patients with a variety of mitochondrial diseases over one to four periods of treatment (2 months each) with coenzyme Q10 plus vitamins K3 and C, riboflavin, thiamine, and niacin, using independent measures of oxidative metabolism to assess efficacy. There were large (> threefold) increases in serum coenzyme Q10 concentrations with treatment, but no measure of oxidative metabolism showed significant improvement with treatment for the group, nor did any individual patient show significant, reproducible, objective clinical improvement. The results suggest that coenzyme Q10 plus vitamin therapy does not significantly improve mitochondrial oxidative metabolism in patients with mitochondrial disease in general. Any clinical benefit that may follow from short-term administration appears slight.

Proton magnetic resonance spectroscopic imaging for metabolic characterization of demyelinating plaques

We used proton magnetic resonance (MR) spectroscopic imaging to determine the serial changes in MR signals from choline, creatine, lactate, and N-acetylaspartate in and around a large demyelinating lesion followed over a period of 8 months. Elevated lactate and choline signals were observed at the first examination 3 days after the onset of symptoms. Reduced N-acetylaspartate signals were observed a few days afterward. The abnormal metabolite signals varied in different regions of the lesion and extended beyond the borders of abnormal signal intensity seen on conventional MR imaging (MRI). On the last examination at 8 months when the lesion appeared much smaller on MRI, choline signals from the center of the lesion were still high, but were falling. Choline signals outside the lesion on MRI had returned to normal as had lactate signals everywhere. Importantly, there was no recovery of N-acetylaspartate signals in or adjacent to the lesion on MRI. This serial study demonstrates the potential of MR spectroscopic imaging for characterizing the chemical pathological evolution of demyelinating lesions in ways that conventional MRI cannot. We propose that abnormal signals from choline can indicate recent regional demyelination, while persistent abnormal signals from N-acetylaspartate can provide an index of irreversible damage in the nervous system.

Proton magnetic resonance spectroscopy for metabolic characterization of plaques in multiple sclerosis

We are investigating the potential of in vivo proton magnetic resonance spectroscopy for noninvasive characterization of the chemical pathology of plaques in magnetic resonance brain images from patients with multiple sclerosis. Spectra localized to chronic, irreversible plaques showed a decrease in the ratio of N-acetyl/creatine resonance intensities relative to normal-appearing white matter. Spectra localized to active plaques showed different metabolite changes as compared with spectra from identical, plaque-free volumes in the contralateral hemispheres. Some active plaques showed either no abnormalities or only an increase in tissue lactate. Spectra from others showed an increased ratio of choline/creatine resonance intensities, with or without a decreased N-acetyl/creatine resonance intensity ratio. In one case, serial observations showed an evolution of changes in spectra from a single plaque from an increased choline/creatine ratio to a decreased N-acetyl/creatine ratio. These observations suggest that proton magnetic resonance spectroscopy may be able to distinguish acute or active from chronic plaques and to characterize the pathologic evolution of active plaques by measurement of local tissue metabolite levels.

Magnetic resonance imaging shows specific abnormalities in the MELAS syndrome

The MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) can be difficult to identify. We report MRI abnormalities that we believe are specific to this disorder in three patients with complete or partial MELAS syndrome. The patients all showed an unusual pattern on T2-weighted MRI with multifocal areas of hyperintense signal confined to the cortex of the cerebrum, cerebellum, and adjacent white matter. Some images suggested selective cortical involvement of deeper layers only. Deep white matter was relatively spared, distinguishing this from usual cerebrovascular disease or the edema after status epilepticus. Specificity of these findings is further suggested by a good correlation of these findings with the previously described unique postmortem brain pathology of MELAS.

In vivo magnetic resonance spectroscopy of brain and muscle in a type of mitochondrial encephalomyopathy (MERRF)

Phosphorus magnetic resonance spectroscopy allows noninvasive measurement of the intracellular phosphate-containing metabolites and intracellular pH in localized volumes of human muscle and brain in vivo. This technique was used to study 8 patients with a mitochondrial cytopathy (myoclonus epilepsy with ragged red fibers). Phosphorus magnetic resonance spectroscopy of resting gastrocnemius muscle demonstrated significantly increased relative intracellular inorganic phosphate concentrations (p less than 0.0005) and decreased phosphocreatine to inorganic phosphate concentration ratios (p less than 0.01) in the patients, although only 3 had myopathic signs or symptoms. We propose, therefore, that phosphorus magnetic resonance spectroscopy of resting skeletal muscle is a useful clinical test in evaluation of progressive myoclonus epilepsy. In contrast to results from muscle, however, the relative phosphate metabolite concentrations and intracellular pH in central volumes of the brains of these patients were normal, despite evidence from our previous positron emission tomography studies suggesting that there is diffuse impairment of cerebral oxidative metabolism.

Characterization of astrocytomas, meningiomas, and pituitary adenomas by phosphorus magnetic resonance spectroscopy

Phosphorus magnetic resonance (MR) spectroscopy allows noninvasive measurement of phosphate-containing compounds and pH within brain cells. The authors obtained localized phosphorus MR spectra from 10 normal brains, four low-grade astrocytomas, six glioblastomas, four meningiomas, and three pituitary adenomas and found differences in the spectra of each tumor type. Compared to normal brain, the spectra from low-grade astrocytomas showed a significant reduction of the phosphodiester (PDE) peak. Glioblastomas were characterized by a significant reduction of the PDE peak, elevation of the phosphomonoester (PME) peak, and a relatively alkaline intracellular pH. The spectra from meningiomas and pituitary adenomas were markedly different from the glial tumors. Meningiomas showed significant reductions in phosphocreatine, PDE, and inorganic phosphate, as well as a relatively alkaline pH. Pituitary adenomas resembled meningiomas, but had a much higher PME peak. Although the number of tumors studied was small, there appears to be a characteristic spectrum associated with these different tumor types. The present findings can be useful in the preoperative identification of these tumors and in furthering understanding of their growth and metabolism in vivo.

Effects of PCB (Aroclor 1254) on non-specific immune parameters in rhesus (Macaca mulatta) monkeys

The effects of low level, chronic polychlorinated biphenyl--Aroclor 1254--(PCB) exposure were investigated on non-specific immune parameters in female rhesus (Macaca mulatta) monkeys. Five groups of monkeys were orally administered with PCB at concentrations of 0, 5, 20, 40 or 80 micrograms/kg bw/day. Immunotoxicity testing was initiated after 55 months of exposure. The serum hemolytic complement activity in all PCB treated groups was significantly higher (P less than 0.05) than that in the control group. A statistically significant dose-related increase in natural killer cell activity was evident at the 75:1 effector to target cell ratio. Similarly, a statistically significant dose-related increase was noted for thymosin alpha-1 levels but not for thymosin beta-4 levels. Statistically significant increased interferon levels were noted in the 20 and 80 micrograms/kg groups compared with the control group while the levels in the 40 micrograms/kg group were decreased significantly compared with the control group. The production of tumor necrosis factor by monocytes in the PCB treated groups was not different to that in the control group. The results indicated that long term exposure to PCB modulate several non-specific immune parameters.

In vivo muscle magnetic resonance spectroscopy in the clinical investigation of mitochondrial disease

We have investigated the sensitivity and specificity of a rapid phosphorus magnetic resonance spectroscopy (MRS) protocol for detecting metabolic abnormalities in vivo in skeletal muscle of patients with mitochondrial disease. We examined 17 patients with mitochondrial myopathies. Sixteen had only mild or minimal myopathic signs and symptoms. Phosphorus magnetic resonance spectra from the resting gastrocnemius muscles showed an abnormal intracellular energy state (marked by an increased intracellular inorganic phosphate concentration) in 14/17. In 3/17, this was associated with a decreased phosphocreatine concentration. We also studied 20 patients with other diseases of muscle (inflammatory myopathies, metabolic myopathies, muscular dystrophies, and myasthenia gravis) that can present with similar clinical features. Spectra showed increased intracellular inorganic phosphate concentrations in 6/20. All of these muscle diseases were associated with evidence of muscle fiber necrosis. Abnormalities in the muscle energy state in these cases may be due to secondary mitochondrial dysfunction. Except for cases of polymyositis and dermatomyositis, these 6 other myopathies could be readily distinguished from the mitochondrial myopathies on the basis of the clinical examination and blood tests. We conclude that phosphorus MRS of resting muscle is practical in a clinical setting and has a useful sensitivity and specificity for mitochondrial myopathies when used in conjunction with standard noninvasive tests.

International Commission for Protection Against Environmental Mutagens and Carcinogens. ICPEMC publication No. 19. The classification of carcinogens identified in the rodent bioassay as potential risks to humans: what type of substance should be tested next?

The relevance of rodent cancer bioassay data to humans is discussed in relation to the needs of regulatory agencies. The usefulness of in vivo and in vitro genotoxicity testing in this connection is also discussed. In the case of rodent carcinogens that do not elicit genotoxicity, it is suggested that homeostatic imbalance, cell proliferation, and other processes may play a major role in tumor development and its importance to the possible ability of the test agent to induce human cancer. These possibilities need to be evaluated on a case by case basis. The methods by which chemicals are selected for the rodent cancer bioassay are also discussed and it is pointed out that naturally-occurring constituents of human foods should in future receive greater priority as a consequence of anticipated changes resulting from biotechnology.

A pilot study on the effects of Aroclor 1254 ingestion by rhesus and cynomolgus monkeys as a model for human ingestion of PCBs

A pilot study using female cynomolgus (Macaca fascicularis) and female rhesus (Macaca mulatta) monkeys was conducted to study the effects of chronic ingestion of polychlorinated biphenyls (PCBs). Four control and four treated monkeys of each species received an apple juice-gelatin mixture containing 0 and 280 micrograms Aroclor 1254/kg body weight/day, respectively, 5 days/wk. The cynomolgus monkeys, which were mature monkeys with a poor breeding history, were treated for approximately 55 wk, while the rhesus monkeys, which were just attaining sexual maturity, were treated for approximately 120 wk. After 38 wk on test, the treated and control rhesus monkeys were mated with untreated males. The clinical signs resulting from the Aroclor 1254 ingestion were similar for both species, and the time of onset after initiation of treatment was not appreciably different between the two species. Several treatment and interspecies differences were found with regard to the haematological and serum biochemistry parameters monitored, but age differences between the two species may have contributed to these findings. Periodic analysis of adipose tissue, blood and faecal specimens for PCBs suggested that the rhesus monkey retained more of the ingested PCB than did the cynomolgus monkey. Following mating, all of the treated rhesus monkeys aborted within 30-60 days after becoming pregnant, while all of the control monkeys had viable offspring.

A proton magnetic resonance spectroscopy study of focal epilepsy in humans

Localized in vivo proton magnetic resonance spectra obtained from diseased areas in 2 patients with chronic localized encephalitis (Rasmussen's syndrome) showed reduced resonance intensities from N-acetyl compounds, suggesting focally decreased N-acetylaspartate concentrations. One of the patients had epilepsia partialis continua secondary to the encephalitis. In this patient, the spectra demonstrated a high lactate resonance intensity (not seen in the normal, contralateral hemisphere) corresponding to an estimated local concentration of about 7.5 mM. We speculate that the observed decrease in the N-acetyl compound resonance may be a biochemical correlate of the neuronal loss characteristic of this disease. The results establish that excessive accumulation of lactate can occur in the human brain as a result of seizure activity even in the absence of ischemia. Thus, bioenergetic compromise may be 1 predisposing factor to the death of excitable cells in the epileptogenic area.

Proton magnetic resonance spectroscopy of human brain in vivo in the evaluation of multiple sclerosis: assessment of the load of disease

Image localized, water-suppressed proton magnetic resonance spectra were obtained from affected brain in patients with multiple sclerosis. In patients with moderate to severe chronic disease, spectra revealed a decreased ratio of N-acetylaspartate to creatine resonance intensities. A normal ratio was obtained from a large recently symptomatic MRI plaque that resolved without sequelae. We propose that the observed metabolite changes can be useful as an index of irreversible CNS injury.

Early metabolic changes following chemotherapy of human gliomas in vivo demonstrated by phosphorus magnetic resonance spectroscopy

The authors have used phosphorus magnetic resonance spectroscopy to monitor pH changes in malignant gliomas following treatment with intravenous and intra-arterial 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU). Image-guided, localized phosphorus spectra of human gliomas in situ were obtained using a 1.5-T whole body combined imaging and spectroscopy system. Initial intravenous BCNU treatment was followed by a transient decrease of tumor intracellular pH by 0.15 +/- 0.03 pH units (mean +/- SD). Superselective intra-arterial administration of the same drug was followed by an increase of tumor intracellular pH by 0.15 +/- 0.6 pH units (mean +/- SD). These changes occurred prior to any changes on x-ray, computed tomography (CT), or magnetic resonance imaging (MRI). In addition to enhancing our understanding of the metabolic effects of BCNU, such changes may correlate with drug efficacy or toxicity and may be useful in guiding therapy in the future.