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Biomedical subjects

J J Gilbert

Publications and source records attributed to J J Gilbert.

At least 37 records · Page 2Linked to original sources
PubMed1988

Postnatal NMR changes in guinea pig central nervous system: potential relevance to experimental allergic encephalomyelitis.

The age of sensitization determines the clinical course of experimental allergic encephalomyelitis (EAE) in the guinea pig. Adult animals immunized with central nervous system (CNS) tissue develop acute, fulminant EAE, whereas a relapsing-remitting illness resembling multiple sclerosis occurs if sensitization occurs in the first 2 weeks of life. This study characterized the changes in the proton nuclear magnetic resonance (NMR) relaxometry and imaging of the CNS during the immediate postnatal period. T1 and T2 relaxation times in cerebral hemispheres and spinal cords of strain 13 guinea pigs were consistently prolonged at birth, progressively shortened in the first few weeks of life, and achieved adult levels by age 6 to 11 weeks. There were no age-dependent differences in T1 and T2 relaxation times and tissue specific gravity in either strain 13 or Hartley guinea pigs following immunization with complete Freund's adjuvant, an agent previously reported to disrupt the blood-brain barrier to IgG and albumin in strain 13 guinea pigs. The CNS of neonatal guinea pigs appeared well myelinated by light microscopy and there was no apparent difference in the extent of myelination between newborn and adult animals. Although it was possible to distinguish gray from white matter in the cervical spinal cord of newborn guinea pigs by magnetic resonance imaging (MRI) techniques, gray/white contrast was less satisfactory in the cerebral hemispheres until approximately 6 weeks of life when it was possible to differentiate gray matter, white matter, and cerebrospinal fluid. This study indicates that NMR relaxation times change during early postnatal life, at a time corresponding to the unexplained differences in susceptibility to an immune challenge. These developmental changes appear to be independent of the degree of CNS myelination.

Aging↗
PubMed1988

Jakob-Creutzfeldt disease associated with Wernicke encephalopathy.

Wernicke disease (WD) is a complication of alcoholism and malnutrition and usually presents acutely and is characterized by disturbances of consciousness, paralysis of the external ocular muscles, and ataxia. The disease results from deficiency of vitamin B 1, or thiamine, an essential coenzyme in intermediate carbohydrate metabolism. On the other hand, Jakob-Creutzfeldt disease (J-C) results from infection with an unconventional agent with a long incubation period and is characterized by a rapidly progressive dementia and histologically by a spongiform encephalopathy associated with neuronal destruction and pronounced astrogliosis. Combination of both diseases has not been reported in the literature previously and their relationship is uncertain. We present 3 cases with this interesting association and consider their relationship.

Aged↗
PubMed1988

Adult onset scapuloperoneal myopathy: diagnostic value of nerve morphometry and multiple muscle biopsies.

In the scapuloperoneal syndrome, differentiation between neurogenic and myopathic processes may be difficult despite electromyography and muscle biopsy. Extensive analysis, including morphometry, was conducted on multiple nerve and muscle biopsies from two adult onset, sporadic cases with the syndrome. These studies confirm a myopathic process and further define the entity of adult onset scapuloperoneal myopathy.

Biopsy↗
PubMed1988

Creutzfeldt-Jakob disease without periodic sharp wave complexes: a clinical, electroencephalographic, and pathologic study.

A comparison of clinical, EEG, and pathologic features was carried out on all cases of autopsy-proven Creutzfeldt-Jakob disease (CJD) studied over the last 10 years. Periodic sharp wave complexes (PSWCs) were present in three but absent in seven patients. Myoclonus was documented in two of the three with and in only one of the seven without PSWCs. The three with PSWCs had severe neocortical and at least mild thalamic involvement; those without PSWCs had more variable disease topography. The diagnosis of CJD should not be rejected if PSWCs are absent.

Aged↗
PubMed1987

Complement depletion suppresses Lewis rat experimental allergic neuritis.

Lewis rats immunized with myelin and complete Freund's adjuvant were treated with cobra venom factor (CVF) which depletes the C3 component of complement. CVF given at day 9 delayed the onset of experimental allergic neuritis (EAN) by 2-3 days and when given at days 9 and 12 delayed the onset of EAN by 4-5 days. Lumbar nerve roots of CVF-treated rats had significantly less demyelination than those from control EAN rats.

Animals↗
PubMed1987

NMR changes in experimental allergic encephalomyelitis: NMR changes precede clinical and pathological events.

In guinea pigs immunized with myelin basic protein (MBP) in complete Freund's adjuvant, experimental allergic encephalomyelitis (EAE) shows a characteristic clinical and pathological course. This study characterized the proton nuclear magnetic resonance (NMR) properties of the central nervous system prior to the onset of clinical signs of EAE. At this time (Days 7-9), the blood brain barrier is disrupted. The effects of the injection of paramagnetic contrast agents gadolinium-DTPA and gadolinium-deferoxamine on the tissue NMR relaxation times were examined. Both proton T1 and T2 relaxation times were prolonged in the spinal cord and the brain prior to the onset of clinical and pathological changes. The largest change was in the thoracolumbar spinal cord where T2 prolongation was 22.9%. Gadolinium-DTPA produced a moderate (5-11%) or marked (9-19%) decrease in control and MBP-treated animals, respectively. Gadolinium-deferoxamine also decreased proton relaxation times but was toxic to all animals, producing respiratory arrest. Changes in proton T2 relaxation times in cord and cerebellum were sufficiently large (greater than 10%) to suggest that they might be visualized by magnetic resonance imaging techniques. We have previously described the changes in proton relaxation times during the acute phase of EAE (S.J. Karlik, G. Strejan, J.J. Gilbert, and J.H. Noseworthy, Neurology 36, 1112 (1986]. This study indicates that proton relaxation times are significantly altered at a time when blood brain barrier disruption occurs prior to the onset of clinical or pathological signs.

Animals↗
PubMed1987

Treatment of experimental allergic neuritis with prednisolone.

Experimental allergic neuritis (EAN) in Lewis rats was treated with prednisolone given prophylactically or therapeutically. Rats treated from the time of immunization with myelin or after the establishment of clinical disease improved more rapidly than controls. Treatment at the onset of clinical signs resulted in less severe disease and more rapid recovery. Rats treated just prior to the onset of clinical signs (day 10) did not develop significant clinical disease and appeared to have less inflammation in their nerves and nerve roots on microscopic examination.

Animals↗
PubMed1987

Critical illness polyneuropathy. A complication of sepsis and multiple organ failure.

Nineteen patients developed polyneuropathy complicating critical illness. They had been admitted to a critical care unit following intubation for cardiac or pulmonary disease and had developed sepsis and multiple organ failure. Approximately one month following intubation, failure to wean from the ventilator and limb weakness prompted neurological referral. Examination disclosed weakness and wasting of muscles and impaired tendon reflexes in most, but not all, patients. Electrophysiological studies in 17 patients revealed attenuated compound muscle and sensory nerve action potential amplitudes and widespread denervation on needle electromyography. Autopsy in 9 patients who died of their critical illness revealed widespread primary axonal degeneration of motor and sensory fibres, with extensive denervation atrophy of limb and respiratory muscles. Survivors recovered from the polyneuropathy three to six months following discharge. Seventeen of the patients were segregated by electrophysiological criteria into mild (8) and severe (9) polyneuropathy categories. An analysis of these two groups failed to reveal putative metabolic, drug, nutritional or toxic factors that might be responsible for the polyneuropathy. Our studies suggest that the mechanism may be a fundamental defect, still unknown, which causes dysfunction of all organ systems in this syndrome.

Adult↗
PubMed1986

The role of myelin lipids in experimental allergic encephalomyelitis. III. Transfer of suppression from guinea pigs recovering from EAE, induced by myelin basic protein--galactocerebroside complexes.

Juvenile strain 13 guinea pigs were immunized with myelin basic protein (MBP) combined with galactocerebrosides (MBP + GC) or with total myelin lipids without GC [MBP + (TL-GC)] in CFA. Control animals received dinitrophenylated-ovalbumin (DNP-OA) in CFA, CFA or IFA alone. The animals injected with MBP + GC showed a higher rate of recovery from the first EAE episode (83%) than those treated with MBP + (TL-GC) (50%). With the exception of the group treated with IFA alone, all animals were refractory to EAE following rechallenge with MBP in CFA 90 days after the first exposure. The in vitro proliferative response to MBP, of peripheral blood lymphocytes (PBLs) derived from guinea pigs freshly sensitized to MBP in CFA, was drastically suppressed in the presence of PBLs from animals injected with MBP + GC. Upon transfer to normal syngeneic recipients, spleen cells from MBP + GC-treated animals completely suppressed the clinical and histological manifestations of EAE following recipient challenge with MBP in CFA. Cell-free supernatants from PBLs and spleen cells of strain 13 guinea pigs treated with MBP + GC inhibited lymphocyte proliferation to MBP, of allogeneic responder cells, and spleen cell supernatants completely suppressed the induction of EAE upon transfer to allogeneic recipients. Suppression could not be transferred with cells from other treated groups. These results suggest that animals immunized with MBP + galactocerebrosides in CFA develop suppressor cells that may be in part responsible for the recovery from the first EAE episode and for protection against rechallenge with MBP in CFA. Their cell-free supernatants act in an MHC-nonrestricted fashion. These results do not rule out an additional protective mechanism since all animals exposed to CFA were refractory to rechallenge despite lack of demonstrable suppressor cell activity.

Animals↗
PubMed1986

The role of myelin lipids in experimental allergic encephalomyelitis. Part 2. Influence on disease production by encephalitogenic doses of myelin basic protein.

Hartley guinea pig CNS myelin lipids (TL) were combined with an encephalitogenic dose (50 micrograms) of myelin basic protein (MBP) and injected together with complete Freund's adjuvant (CFA) into juvenile strain 13 guinea pigs. All the animals developed acute EAE and recovered, but only 50% had a single mild relapse during an observation period of 12 months. To determine the effect of individual myelin lipids on EAE, purified fractions comprising the galactocerebrosides (GC) or gangliosides (GANG) were combined with 50 micrograms MBP together with phosphatidyl choline (PC) and cholesterol (CHOL) and injected with CFA into juvenile Hartley guinea pigs. Control animals received MBP mixed with PC and CHOL or MBP alone, in CFA. The incidence of acute EAE was similar in all groups, but the highest percent recovery (69%) was seen in animals immunized with the MBP-GC combination. All animals that developed acute EAE in the control groups died. Histologically, CNS myelin breakdown was present during the acute attack except in the MBP control group. Parameters of cell-mediated immunity (CMI) showed good correlation with the clinicopathological findings in animals that received MBP-GC or MBP alone. In most animals, serum anti-MBP antibodies were detected as early as 10 days post-immunization (p.i.) whereas anti-lipid antibodies were found at 90 days p.i. Animals that received MBP-PC did not show any positive CMI or serum antibodies although they developed severe disease. The results indicate that myelin lipids, especially the galactocerebrosides, contribute to the development of chronic EAE; however, the mechanism by which this occurs is still obscure.

Animals↗
PubMed1986

Morphologic and morphometric analysis of muscle in X-linked myotubular myopathy.

The X-linked form of myotubular myopathy is highly lethal in neonates. Several autopsy-derived muscles from two probands of a new kindred who survived for 100 days because of intensive supportive care were analyzed by light microscopy, morphometry, enzyme histochemistry, and electron microscopy. The results were compared with a similar analysis of muscle from control fetal and neonatal subjects. The findings, in addition to the characteristic centronucleated hypotrophic myofibers, included widespread myofiber degeneration and focal contraction band necrosis that differed from the types seen in other myopathic and dystrophic muscle diseases. A high frequency of degenerating nuclei that often contained large nucleoli was observed. Because of the paradoxic nuclear morphology, nuclear failure (in migration and myofibrillogenesis) is believed to be of central importance in the pathogenesis of this disease.

Histocytochemistry↗
PubMed1986

An acute axonal form of Guillain-Barré polyneuropathy.

Five patients with a clinical diagnosis of acute Guillain-Barré polyneuropathy (GBP) had electrically inexcitable motor nerves. All were quadriplegic. One patient died and 3 of the 4 survivors showed poor recovery. Autopsy studies on the patient who died showed severe axonal degeneration in nerve roots and distal nerves without inflammation or demyelination. Electrophysiological studies in these patients suggested that the predominant process was axonal degeneration. These cases may represent a separate clinicopathological entity, and constitute a variant of GBP characterized by an acute axonal neuropathy.

Acute Disease↗
PubMed1986

NMR studies in experimental allergic encephalomyelitis (EAE): normalization of T1 and T2 with parenchymal cellular infiltration.

The central nervous system (CNS) of guinea pigs undergoing acute experimental allergic encephalomyelitis (EAE) induced by whole CNS shows a characteristic progression of proton NMR relaxation times that correlates with pathologic features of the disease. Specifically, T1 was prolonged during meningeal infiltration and perivascular inflammation. T2 was increased with demyelination. Both proton T1 and T2 values, however, were normalized in active lesions containing an extensive cellular response (encephalitis, myelitis).

Animals↗
PubMed1985

Brain neurotransmitter abnormalities in neuronal intranuclear inclusion body disorder.

Biochemical markers for the major neurotransmitter systems were measured in the brain of a patient who died with neuronal intranuclear inclusion disease. A severe nigrostriatal dopamine deficiency constitutes the basis for the parkinsonian features in the patient. A marked loss of brain norepinephrine and serotonin was found in the basal ganglia and hypothalamus. Brain amino acid (gamma-aminobutyric acid and glutamate) and cholinergic (choline acetyltransferase activity) systems were either normal or less severely affected.

Adolescent↗
PubMed1985

Blood-nerve barrier studies in experimental allergic neuritis.

The integrity of the blood-nerve barrier (BNB) was studied during the development of experimental allergic neuritis (EAN). Lewis rats immunized with bovine nerve or myelin plus complete Freund's adjuvant developed histological lesions of EAN in nerve roots by 10-12 days and in sciatic nerves by 12-14 days. Evans blue-albumin (EBA) and horseradish peroxidase (HRP) were injected i.v. 1 h prior to killing on days 6-18. Perivascular and diffuse endoneurial leakage of the tracers was seen in nerve roots by 10-12 days post immunization (p.i.) and in sciatic nerves by 12-14 days. This coincided with the appearance of endoneurial infiltration with inflammatory cells and endoneurial proteinaceous edema at a time when Schwann cell and myelin changes were still minimal. Therefore, an alteration in BNB permeability occurs early in EAN, coincident with inflammatory cell infiltration. This could be an expression of delayed hypersensitivity, yet it would also facilitate the entry of anti-myelin antibodies into the endoneurium where they could initiate demyelination.

Animals↗
PubMed1985

The encephalopathy of sepsis.

Twelve fatal cases of encephalopathy associated with sepsis were examined in a ten-year retrospective study. The sources of infection and organisms isolated were variable. Six of the patients had focal neurologic signs; five had seizures. The level of consciousness varied from drowsiness to deep coma, and electroencephalograms revealed diffuse or multifocal abnormalities. Computed tomographic head scans and cerebrospinal fluid examinations were usually unremarkable. Eight patients had disseminated microabscesses in the brain at autopsy. Four patients had proliferation of astrocytes and microglia in the cerebral cortex, a feature associated with metabolic encephalopathies. Additional findings included cerebral infarcts, brain purpura, multiple small white matter hemorrhages, and central pontine myelinolysis. Although sepsis may cause encephalopathy by producing disturbances in cerebral synaptic transmission and cerebral energy production through a toxic mechanism, bacterial invasion of the brain with the formation of disseminated microabscesses is also an important cause.

Adult↗