Serum creatine kinase-BB levels and cerebral cortical creatine kinase activity in senile dementia of the Alzheimer type

A rise in serum creatine kinase-BB (CK-BB) levels has been reported previously in cases of dementia. In the present study the levels of serum CK-BB have been measured in patients clinically assessed to have senile dementia of the Alzheimer's type (SDAT) and in cognitively intact individuals, matched for age, by a specific two-site monoclonal immunoradiometric assay. No significant difference was found between the 2 groups. Total creatine kinase activity in temporal cortex (Brodmann area 21 and 22) was also found to be similar in brains from SDAT or control cases, obtained at autopsy. These results suggest no major change in the permeability of the blood-brain barrier to this enzyme in SDAT patients.

Intralaminar distribution of neurotransmitter-related enzymes in cerebral cortex of Alzheimer's disease

The intralaminar distribution of choline acetyltransferase, galactocerebrosides, gangliosides and proteins were determined in frontal (Brodmann's area 9) and temporal (Brodmann's area 22) cortices from subjects with autopsy-proven Alzheimer's disease and controls matched for sex, age and postmortem delay. In normal brain choline acetyltransferase (CAT) activity was higher in the II and IV layers in the temporal cortex, while in frontal cortex CAT activity was relatively high in the II-III layer, appearing as a single peak. The intracortical distribution of galactocerebrosides normally shows a trend to a higher activity from the pial surface to white matter either in frontal or temporal cortices. Higher concentrations of gangliosides were associated with the cell body layers in either frontal or temporal cortices. In either frontal and temporal cortices from 5 patients with Alzheimer's disease the pattern of intralaminar distribution of CAT activity was completely disrupted and it was significantly lower than in all cortical layers of the controls. Galactocerebrosides concentration was significantly decreased in the lower layers (IV, V and VI) in both frontal and temporal cortices and ganglioside sialic acid concentration was also decreased in the Alzheimer brain consistently in the lower (III-IV) layers of the frontal and temporal cortices. These observations indicate a widespread involvement of cholinergic activities through all cortical layers. However, the selective decrease in galactocerebroside concentration in the lower layers (IV-VI) suggests a selective loss of ascending fibers from subcortical nuclei. The decreased concentration of ganglioside sialic acid in lower layers suggests a selective axodendritic degeneration in these laminae of frontal association and temporal cortex in Alzheimer's disease.

Subcellular pathology of human neurodegenerative disorders: Alzheimer-type dementia and Huntington's disease

Activities of enzyme markers of subcellular organelles have been measured in brain tissue from subjects with Alzheimer-type dementia (ATD) and Huntington's disease (HD). Significant increases in the activity of the lysosomal enzyme beta-glucuronidase were observed in both ATD temporal cortex and HD putamen. It is suggested that beta-glucuronidase activity may be a useful biochemical indicator of cellular damage in the CNS. A significant reduction in neutral alpha-glucosidase activity was observed in ATD temporal cortex and HD putamen. This change may reflect an alteration in glycoconjugate processing and may relate to the susceptibility of neurones to the degenerative processes of ATD and HD.

Asymmetrical distribution of aminopeptidase activity in the cortex of rat brain

The levels of soluble aminopeptidase (AP) activity were measured in the right and left frontal (FC), parietotemporal (PTC) and occipital (OC) cortex of male albino rat brains. The results showed more AP activity in the left cortex than in the right. Analyzing these results further, we found that the differences are significant for frontal cortex but not for parietotemporal nor occipital cortex. However, 76% of the rats were left-predominant for AP activity in the 3 cortical areas studied.

Astroglial contribution in human temporal lobe epilepsy: K+ activation of Na+,K+-ATPase in bulk isolated glial cells and synaptosomes

Potassium activation of Na+,K+-ATPase within glial cells and synaptosomes, bulk isolated from temporal neocortices of 15 patients with hippocampal-amygdalar epilepsy were compared to two patients with extratemporal complex partial epilepsies and 8 post-mortem temporal neocortices from patients with no known neurological ailments. Temporal neocortices were obtained from 17 patients who had undergone 'en bloc' anterior temporal lobectomy. In 15 patients with hippocampal amygdalar epilepsy, enzymatic activities of glial fractions were lower than those shown in 2 control lobectomy specimens and post-mortem brains. Glial enzymes had no or poor activation when K+ concentrations increased from 3 to 18 mM. Two patients served as control lobectomy specimens since they had normal neuropathological studies, and electroclinical correlations indicated an extratemporal lobe origin for complex partial seizures. In these two control specimens, glial Na+,K+-ATPase activities were similar to normal animals or post-mortem specimens. Na+,K+-ATPase activities were also slightly decreased in the synaptosomal fractions of patients with hippocampal-amygdalar epilepsy. K+ response of enzyme activities, however, corresponded to what had been described in controls, i.e. hyperbolic curves saturated at 3-6 mM K+. These results indicate that a defect in glial Na+,K+-ATPase exists in temporal neocortices of patients with hippocampal-amygdalar epilepsy.

High-molecular-weight forms of somatostatin are reduced in Alzheimer's disease and Down's syndrome

Four molecular forms of somatostatin-like immunoreactivity (SOM-LI) are present in the human temporal cortex: SOM-14, SOM-28 and high-molecular-weight forms (HMW-SOM) of 7500 and 12,000 daltons. SOM-14 and HMW-SOM are depleted in cortical tissue from cases of pre-senile Alzheimer-type dementia (ATD), but there is a disproportionate reduction in HMW-SOM. In cases of Down's syndrome (DS) with the neuropathological and neurochemical changes of ATD, the total concentration of SOM-LI was similar to that in control cases and the proportions of molecular forms present were comparable. However, there was a significant reduction in the concentration of HMW-SOM. These results show that ATD and DS may share a common abnormality in the biosynthesis and/or post-translational processing of cortical SOM.

Aromatase activity in the perinatal rat forebrain: effects of age, sex and intrauterine position

Sex and regional differences in aromatase activity were characterized in brains of rats sacrificed on embryonic days 18 (E18) and 20 (E20) and on postnatal days 2, 4 and 13 (D2, D4, D13). Aromatase activity was measured in vitro in homogenates of the hypothalamus/preoptic area (HPOA) and temporal lobe (TL) from individual rats, using [3H]19-hydroxyandrostenedione as substrate in the presence of NADPH. The apparent Km of aromatase for 19-hydroxyandrostenedione in TL at D4 was similar in males (34 nM) and females (22 nM,). Aromatase activity in the HPOA was highest prenatally (E18) and gradually declined to low levels by D13. Aromatase activity in the TL remained constant from E18 to D2, increased significantly on D4, and subsequently declined to low levels by D13. The level of aromatase activity was significantly greater in males than in females on E18 and D4 in the HPOA and on D4 in the TL. Differences in aromatase activity within regions of the HPOA were studied at E20 and D4. At both ages, the activity was highest in the preoptic area, lower in the anterior hypothalamus (AH), and lowest in the posterior hypothalamus. Aromatase activity was significantly higher in males than in females in the AH, but only on D4. The contiguity of males in utero was not correlated with aromatase activity in brain regions of adjacent female fetuses. The present results indicate that significant sex differences in aromatase activity exist in specific brain regions only at discrete times during perinatal development.(ABSTRACT TRUNCATED AT 250 WORDS)

Glutathione peroxidase activity in Parkinson's disease brain

Glutathione peroxidase is an enzyme of major importance in the detoxification of peroxides in brain. Using the spectrophotometric procedure of Paglia and Valentine [8] and Beutler [2] we measured the activity of this enzyme in autopsied brain from 12 patients dying with idiopathic Parkinson's disease and 11 neurologically normal adults matched with respect to age and postmortem interval. In the Parkinson's disease patients glutathione peroxidase activity was slightly but significantly reduced in several brain areas including substantia nigra. Although the magnitude of the glutathione peroxidase deficiency in Parkinson's disease substantia nigra was small (19% reduction), coupled with the reported marked deficiency of reduced glutathione [9] it may represent one of the contributing factors leading to nigral dopamine neurone loss.

Glutathione peroxidase activity in surgical and autopsied human brains

Glutathione peroxidase (GSHPx) activity was assayed in normal cerebral gray and white matter samples obtained from frontal, temporal, occipital and parietal lobes during surgical approach to an underlying lesion, and also in normal autopsied human frontal gray and white matter. GSHPx was assayed by a 2 step enzyme reaction which was monitored by following the oxidation of NADPH at 340 nm. It was found that all the brain samples studied contained GSHPx activity. Parietal lobe appeared to have the lowest GSHPx activity compared to temporal, occipital or frontal lobes. Mean enzyme activity in autopsied samples was comparable to that in surgical material. However, considerable loss of activity was observed after 10 years of tissue storage at -80 degrees C.

Neurochemical enzyme changes in Alzheimer's and Pick's disease

Neurochemical investigations of the whole temporal lobe of cases with Alzheimer's disease (n = 15); 80.7 +/- 1.7 yr), Pick's disease (n = 3; 65 +/- 1.7 yr), and age-matched controls (n = 18; 74.7 +/- 2.6 yr), demonstrate that Alzheimer's and Pick's disease are primary degenerative brain diseases. The activities of glycolytic enzymes, ATPases, carbonic anhydrase, acetylcholinesterase and protein kinase were significantly lower in Alzheimer's and in Pick's disease than in age-matched controls. Pick's disease is characterised by a more pronounced reduction of the enzymes investigated, which is considered to be an expression of a more dramatic degenerative process. The differences between Alzheimer's disease and Pick's disease are quantitative.

Tetrahydrobiopterin metabolism in the temporal lobe of patients dying with senile dementia of Alzheimer type

There is a defect in tetrahydrobiopterin metabolism in brains from subjects with senile dementia of Alzheimer type compared to age-matched controls. This defect results in lowered total biopterin concentrations in brain. Brains from subjects with senile dementia of Alzheimer type retain their ability to synthesis neopterin and have normal dihydropteridine reductase activity, indicating a specific loss of ability to convert dihydroneopterin triphosphate to tetrahydrobiopterin.

Glial and neuronal Na+-K+ pump in epilepsy

Because high extracellular K+ concentrations (18-20 mM) increased glial Na+- and K+ -dependent adenosine triphosphatase [(Na+ + K+)-ATPase] activities, while this increase was not observed in neuronal preparations, it is hypothesized that K+ released in the extracellular space during neuronal firing is actively taken up by glial cells. In acute and chronic epileptogenic lesions of cats, glial (Na+ + K+)-ATPase dramatically decreased when compared to both control animals and the perifocal area, while its activation by extracellular K+ in concentrations between 3 and 18 mM was absent 3, 6, and up to 45 days after production of freezing lesions. Similar results were observed in 13 specimens of anterolateral temporal neocortex obtained during temporal lobectomies in patients with intractable temporal lobe epilepsy, compared with postmortem human specimen or control brain tissues. Hence, a glial (Na+ + K+)-ATPase abnormality exists in epileptogenic tissue. Further experimental data are presented supporting the notion that this glial abnormality may favor the transition from interictal episodes to ictal phenomena.

The nucleus basalis in Alzheimer's disease: cell counts and cortical biochemistry

The cell density in the Nucleus Basalis in six patients with clinical and histological evidence of Alzheimer's disease and reduced choline acetyltransferase activity in frontal and temporal cortex was found to be in approximately 50% of the cell count in five control subjects.

The temporal lobe in dementia of Alzheimer's type

Evidence is presented of a predilection of neurofibrillary tangle formation and choline acetyltransferase deficiency for the temporal lobe in Alzheimer's disease. Together with evidence from studies of cerebral atrophy, 5-HT levels, and clinical findings, this indicates that changes in the temporal lobe may play a prominent role in Alzheimer's disease, especially in elderly patients.

Extensive loss of choline acetyltransferase activity is not reflected by neuronal loss in the nucleus of Meynert in Alzheimer's disease

Choline acetyltransferase activity in discrete tissue punches from the nucleus of Meynert and in tissue from the temporal cortex was reduced by at least 90% and 75%, respectively, in 5 out of 6 elderly cases of Alzheimer's disease compared with 5 normal cases. In contrast, estimates of neurone density in these same cases revealed that there was only, on average, a 33% neurone loss in the nucleus of Meynert in Alzheimer's disease. These observations suggest that a key pathological change in Alzheimer's disease may be the 'down regulation' of transmitter-specific enzyme production in cholinergic neurones, and that neurone loss itself may be a secondary feature of the disease.

Alzheimer's disease. Correlation of cortical choline acetyltransferase activity with the severity of dementia and histological abnormalities

We have examined the choline acetyltransferase [CAT] activity in autopsy samples of frontal and temporal lobe cortex from 47 patients (31 with Alzheimer's disease, 4 with dementia due to cerebrovascular disease and 12 undemented controls) and compared it with the severity of dementia during life and with the numbers of argyrophilic plaques and neurofibrillary tangles in the corresponding areas of cortex in the contralateral cerebral hemisphere. CAT activity was significantly reduced, most severely in the temporal lobe, in patients with Alzheimer's disease but not in patients with a cerebrovascular cause for their dementia, and CAT activity showed no significant reduction with age in the undemented control patients. In the patients with Alzheimer's disease the reduction in CAT activity was significantly correlated with the severity of dementia and with the numbers of neurofibrillary tangles, but not argyrophilic plaques, present in the corresponding contralateral cortex.

Properties of cloned human glioblastoma cells. Release of a specific protease

We cloned a previously characterized glioblastoma-derived parent cell line (12-18) in order to obtain a relatively homogenous population of human neural cells of neoplastic origin. These cells reach high densities in culture (over 100,000 cells/cm2) and have a high mean DNA content per cell of 18.1 +/- 0.9 pg. A histogram of the cloned cells' chromosome numbers revealed one peak and a modal near diploid number of 52, whereas the parent cell line had expressed polyploidy, with several peaks (including 52) at population doubling level 16. Several consistent results were obtained by Giemsa staining. A persistent structural alteration was the duplication of the long arm of chromosome #9 on to another arm of #9, and the translocation of the short arm of #9 to chromosome #21. We further observed that these cloned cells secrete a specific protease, a plasminogen activator (PA), into serum-free medium (SFM). This enzyme was assayed by the conversion of purified plasminogen to plasmin and the subsequent degradation by plasmin of 125I-labelled fibrin. Glioblastoma-derived cells had higher levels of cell-associated PA activity (2.9-fold) and released more PA activity into SFM (22-fold) than human fetal neural cells. The presence of this protease suggests a mechanism for the invasive character of these neoplasms (glioblastoma multiforme) in vivo.

Choline acetyltransferase (ChAT) activity differs in right and left human temporal lobes

Choline acetyltransferase (ChAT) activity was studied in different areas and in sequential sections of the cortical layers in the first temporal gyrus of left and right hemispheres of four human brains. The ChAT activity values obtained in all the samples from left hemisphere were significantly higher than in the right hemisphere. Furthermore, the study of ChAT activity in the cortical layers in Brodmann area 22 shows a greater left prevalence of enzymatic activity in cortical layers II and IV. The biochemical data seem to suggest a possible morphologic and/or functional difference between the two hemispheres.

Reduced dopamine-beta-hydroxylase activity in Alzheimer's disease

The activity of the noradrenergic marker enzyme dopamine-beta-hydroxylase was measured in brains removed postmortem from control patients and patients with Alzheimer's disease. Enzyme activity was decreased in the frontal and temporal cortices and hippocampus in patients with Alzheimer's disease, but was within the normal range in patients with depression, multiinfarct dementia, and terminal coma.The decrease in enzyme activity in Alzheimer's disease may reflect an abnormality of cortical noradrenergic fibres in some patients with the disease.

Cerebral tumours induced by ENU; changes of adenylate cyclase activity in the tumour latency time

Tumours of the nervous system have been induced by transplacental ENU. Until the fourth month of life the tumoural lesions appear as mixed glial proliferations or oligodendroglial foci. From the fourth month on they develop as glial micro- and macrotumours or as isomorphic and polymorphic oligodendrogliomas. The adenylate cyclase activity studied during these two distinct phases of tumour development was markedly reduced in brain tumours, independent of their cellular origin, compared with the level in the normal brain. On the other hand, the activity of the enzyme responsible for the synthesis of cyclic AMP is significantly increased during the first period of tumour development when early neoplastic proliferations are present.

Changes in brain cholinesterases in senile dementia of Alzheimer type

Acetyl- and butyryl-cholinesterase activities have been measured biochemically in normal brain tissue, in senile dementia of Alzheimer type and in mental disorders without Alzheimer-type abnormalities. Acetylcholinesterase was significantly reduced and butyrylcholinesterase significantly increased, compared with the normal, in the hippocampus and temporal cortex of the Alzheimer cases. No significant enzyme changes were seen in the other diseases investigated including multi-infarct dementia, schizophrenia and depression. There was no correlation between age and acetylcholinesterase activity, but a significant positive correlation between the butyrylcholinesterase activities with increasing age (60-90 years) was found in the hippocampus. The possible connection between cholinergic system pathology and these cholinesterase abnormalities in Alzheimer dementia is discussed.

S-adenosylmethionine-dependent N-methyltransferase activity in autopsied brain parts of chronic schizophrenics and controls

The transmethylation hypothesis of schizophrenia proposes that the disease results from excessive accumulation of methylated derivatives of biogenic amines. To test the hypothesis that an abnormality in S-adenosylmethionine-dependent N-methyltransferase (SAM enzyme) might play a role in schizophrenia, the authors compared SAM enzyme activity of in vitro preparations of 6 brain regions obtained at autopsy from chronic schizophrenics and nonschizophrenic controls. An analysis of variance demonstrated statistically significant differences among brain regions but not between schizophrenics and controls.

Kinetic properties of hexokinase in resected temporal lobes of patients with drug-resistant epilepsy

Properties of the cerebral glycolytic enzyme, hexokinase, were studied in biopsy samples of human temporal lobe, obtained during lobectomy for drug-resistant epilepsy and compared "blind" with contol biopsy samples of human cerebral cortex. No significant changes in the total activity or subcellular distribution of the enzyme were observed but the Km value for glucose was altered. The 17 control samples gave a normal mean value for Km (glucose) of 0.05 mM and the 14 epileptic samples gave a significantly higher mean value of 0.09 mM. The drugs used in previous treatment of the epilepsies were "scored" with respect to type and dose; analysis of these in relation to the kinetic results eliminated the possibility that the increase in Km value was an artifact due to the drugs. The observed change in enzyme kinetic properties is discussed in terms of potential interactions of small molecules with the isoenzymes of cerebral hexokinase.

Parkinson's disease: activity of L-dopa decarboxylase in discrete brain regions

The activity of L-dopa decarboxylase was greatly reduced in the striatum, less so in the hypothalamus, and unchanged in the cortex of brains of patients with Parkinson's disease. However, it appears that even in the striatum enough activity remained to allow for the formation of dopamine from L-dopa in patients treated with large doses of L-dopa.