Effects ofTrans-clomiphene in combination with AY-9944 on rat CNS morphology and biochemistry

Summary Developing rats were injected intraperitoneally twice weekly with a combination of two hypocholesterolemic agents:trans-clomiphene, 50 mg per kg body weight, and AY-9944, 5 mg per kg body weight. Treatment was initiated at 5 days of age. Biochemical and electron microscopic examination was carried out on animals sacrificed at 20 days of age. Only rarely were cytoplasmic inclusion bodies seen in the CNS. Biochemical analysis of the brain and spinal cords of treated animals indicated the abnormal accumulation of three sterols, zymosterol (5-cholesta-8,24-dien-3-ol), 7-dehydrocholesterol (cholesta-5,7-dien-3-ol) and 7-dehydrodesmosterol (cholesta-5,7,24-trien-3-ol). The 7-dehydrosterols constituted from 56–66% of the total CNS sterol component. Zymosterol was a relatively minor (2.4–5.0%) component.     

Apolipoprotein E co-localizes with newly formed amyloid β-protein (Aβ) deposits lacking immunoreactivity against N-terminal epitopes of Aβ in a genotype-dependent manner

Different types of amyloid -protein (A)-containing plaques occur in brains of Alzheimers disease (AD) patients. Diffuse plaques seen during early stages of AD differ from neuritic plaques in later stages both with respect to the length of the A peptides and the presence of other proteins, e.g., apolipoprotein-E (apoE). Since apoE is involved in A transport and clearance, and the 4-allele of the apolipoprotein-E gene (APOE) is a major risk factor for sporadic AD, it is plausible to speculate that apoE plays a pathophysiological role in the initiation of A deposition. To address the issue of whether binding of apoE to A is involved in initial A deposition, we studied the human medial temporal lobe of 60 autopsy cases encompassing the full spectrum of AD-related pathology. In temporal lobe regions, which become involved for the first time at a given stage of -amyloidosis, all plaques represent newly formed plaques, and these were studied with immunohistochemical methods. ApoE was present in 36 cases, and was frequently co-localized with newly formed A deposits detectable with anti-A₄₂ but not with antibodies raised against N-terminal epitopes of A. In 10 additional cases, immunoreactivity against apoE was completely lacking in newly formed plaques, which, at the same time, displayed immunoreactivity against N-terminal epitopes of A. The failure of N-terminal epitopes of A to co-localize with apoE in newly formed plaques indicates that these deposits presumably contain apoE-A complexes, in which the N-terminal epitopes of A are often concealed after complexing with apoE, thus preventing subsequent binding of antibodies. Moreover, apoE-positive newly formed plaques were seen more frequently in APOE 4/4 cases than in non-APOE 4/4 individuals, thereby underlining the potentially crucial role of apoE for the development of A deposits.     

The effect of oxidative stress on amyloid precursor protein processing in cells engaged in β-amyloidosis is related to apolipoprotein E genotype

The reduced antioxidative defense in allele 4 carriers is suggested to contribute to -amyloidosis in Alzheimers disease and Downs syndrome. We studied the effect of oxidative stress on accumulation of amyloid- peptide (A) in vascular smooth muscle cells (SMCs) that are engaged in production of amyloid- in vivo. Previously, we found that oxidative stress caused by ferrous ions induced accumulation of A-apolipoprotein E deposits in lysosomes and was associated with a greater oxidative protein damage in 4 carriers. Here, we demonstrate that ferrous ions induce formation of A deposits also in vascular tunica media in organotypic cultures of whole brain vessels, suggesting the role of oxidative stress in development of vascular -amyloidosis. Cellular accumulation of A in SMCs treated with ferrous ions was associated with a greater accumulation of C-terminal amyloid precursor protein (APP) fragments in 4/4 than in 3/3 myocytes and reduced the amount of soluble APP in 3/3, but not 4/4, cultures. Antioxidant vitamin E prevented these effects, and, when applied alone, diminished the amount of APP C-terminal fragments and increased the amount of secreted APP in 3/3, but not 4/4, cells. C-terminal APP-immunoreactive material was accumulated in lysosomes partly with A- and N-terminal APP immunoreactivities. These results suggest that the increased accumulation of APP and its fragments in lysosomes may yield additional amounts of cellular A, particularly in 4 carriers. We hypothesize that the altered processing of APP in SMCs locally exposed to oxidative stress facilitates cellular deposition of A and contribute to the increased risk of development of -amyloidosis in 4/4 carriers.     

A 3’-UTR polymorphism in the oxidized LDL receptor 1 gene increases Aβ40 load as cerebral amyloid angiopathy in Alzheimer’s disease

It is presently unclear whether polymorphic variations in the oxidized low-density lipoprotein receptor 1 (OLR1), or low-density lipoprotein receptor-related protein 1 (LRP1), genes act as risk factors for Alzheimers disease (AD). In the present study, we have investigated the extent of amyloid protein (A) deposition as cerebral amyloid angiopathy (CAA) or senile plaques (SP) in relationship to OLR1 +1071 and +1073 polymorphisms and LRP1 C766T polymorphism in patients with AD There was an increased A₄₀ load as CAA, but not as SP, in frontal cortex of AD patients carrying OLR1+1073 CC genotype, compared to those with CT, TT or CT+TT genotypes, but only in those individuals without apolipoprotein (APOE) 4 allele. No differences in total A or A₄₂ load as CAA or SP between OLR1+1073 genotypes was seen, nor were there any differences between OLR1+1071 and LRP1 genotypes for any measure of A. Present data suggests that homozygosity for the C allele for OLR1+1073 polymorphism, selectively in individuals without APOE 4 allele, may impair clearance of A, and particularly A₄₀, from the brain across the blood-brain barrier, leading to its diversion into perivascular drainage channels, thereby increasing the severity of CAA in such persons.     

GSK-3β in cerebrospinal fluid of schizophrenia patients

Summary. Cerebrospinal fluid contains proteins and metabolites of brain origin and was extensively studied in psychiatry in the 1970s with few definitive results. We have recently found 40% reduced protein levels of GSK-3 in schizophrenia in postmortem prefrontal cortex, but our attempt to develop a diagnostic marker using peripheral lymphocyte GSK-3 was not successful. In this study we aimed to find whether the reduction in brain GSK-3 is reflected in CSF of schizophrenia patients. We report a significant reduction in CSF GSK-3 protein levels in six schizophrenia patients compared to seventeen healthy subjects. Our results corroborate other studies in which CSF protein levels reflect the alteration found in these proteins in schizophrenia patients postmortem brain.     

Cytoplasmic and axoplasmic density variations in relation to hyperactivity

Summary The density of the cytoplasm and axoplasm of the anterior horn cell in rats was determined by X-ray microradiography. The average density of the cytoplasm of more than 400 cells from control rats was 0.31 g/³, while that of over 600 cells from rats fed IDPN (- iminodipropionitrile) was 0.43 g/³.Hyperactivity developed during the first 5 weeks and was associated with a gradual increase in cytoplasmic density to 0.51 g/³.At 6 weeks there was a drop in density to 0.36 g/³ which coincided with the appearance of axonal balloons having a density of 0.17 g/³.During the 7–12th week on the diet, the cytoplasmic density showed a gradual increase to 0.59 g/³ and the balloons to 0.29 g/³.The volume of the nerve cells remained fairly constant. The density increases were discussed in relation to hypertrophy, dystrophy, and hyperactivity.

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Zusammenfassung Die Dichte des Cytoplasmas und Axoplasmas der Vorderhornzellen von Ratten wurde durch Röntgenmikroradiographie bestimmt. Die mittlere Dichte des Cytoplasmas von mehr als 400 Zellen der Kontrollratten war 0,31 g/³, während die mittlere Dichte von mehr als 600 Zellen der Ratten, die mit IDPN (- iminodipropionitrile) gefüttert waren, 0,43 g/³ war.Hyperaktivität entwickelte sich während der ersten 5 Wochen und war mit einer progressiven Zunahme der Cytoplasmadichte bis auf 0,51 g/³ verbunden.Nach 6 Wochen sank die Dichte auf 0,36 g/³. Diese Tatsache traf mit dem Auftreten der Axonauftreibungen zusammen, die eine Dichte von 0,17 g/³ hatten.Nach 7–12 Wochen zeigte die Cytoplasmadichte eine progressive Zunahme auf 0,59 g/³ und die der Auftreibungen eine Zunahme auf 0,29 g/³.Das Volumen der Nervenzellen blieb ziemlich konstant.Die möglichen Zusammenhänge zwischen Zunahme der Dichte, Hypertrophie, Dystrophie und Hyperaktivität werden dargestellt.

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Supported by U. S. Public Health Grant NB 1305.     

Regional brain kinetics of 6-fluoro-(β-11C)-L-dopa and (β-11C)-L-dopa following COMT inhibition. A study in vivo using positron emission tomography

Summary The regional brain kinetics of (-11C)-L-dopa and 6-fluoro-(-11C)-L-dopa was measured in six Rhesus monkeys using positron emission tomography (PET). Radioactivity accumulated specifically in the striatal region and the increase in L-dopa-derived radioactivity utilization with time was calculated using surrounding brain as a reference area, this being devoid of dopaminergic activity. The rate constant for selective striatal utilization i.e. grossly decarboxylation was 0.0110 ± 0.0007 (S.D) and 0.0057 ± 0.0006 min1 for (-11C)-L-dopa and 6-fluoro-(-11C)-L-dopa, respectively. After pre-treatment of the monkeys with the peripherally and centrally active catecholamine-O-methyl transferase (COMT) inhibitor Ro 40-7592 10 mg/kg, the decarboxylation rate remained unchanged (0.0112 ± 0.0015 min-1) for (11C)-L-dopa, whereas an increase in rate was measured for 6-fluoro-(-11C)L-dopa (0.0092 ± 0.0015 min–1). Differences in the distribution of radiolabelled metabolites i.e. the corresponding O-methyl-L-dopa in the reference area is most probably the reason for the difference in calculated decarboxylation rate seen between the radiotracers. The higher decarboxylation rate measured for 6-fluoro-(-11C)-L-dopa after blockade of COMT shows that the radiolabelled metabolites i.e. 6-fluoro-O-methyl-(-11C)-L-dopa significantly contributes to background radioactivity.     

The inflammatory lesion of T cell line transferred experimental autoimmune encephalomyelitis of the Lewis rat: distinct nature of parenchymal and perivascular infiltrates

We have investigated the T cell receptor (TCR) repertoire in the inflammatory infiltrates of T line-transferred experimental autoimmune encephalomyelitis (EAE) of the Lewis rats. Using a panel of TCR V-specific monoclonal antibodies (mAbs) and immunocytochemistry, we studied the nature of the T cells entering the central nervous system (CNS) after transfer of either myelin basic protein (MBP)-reactive, or MBP-reactive but non-encephalitogenic T cell lines. All the MBP-specific T cell lines predominantely used the V8.2 TCR chain. T cell lines specific for the tuberculin purified protein derivative (PPD), using TCR V genes different from V8.2, served as controls. We first studied the time course of T cells entering the CNS. In all recipient rats, small, but significant numbers of -TCR-expressing infiltrate cells appeared in the CNS within the first 24 h after T cell transfer. In animals injected with either type of MBP-reactive T cells, the early infiltrate cells were preferentially located within the parenchyma of the spinal cord, while in PPD T lineinjected rats, the lymphocytes were mostly found in the meninges. TCR V gene usage was examined on the peak of clinical disease. Six days after T cell transfer, the TCR repertoire used by infiltrating lymphocytes in general seemed to be highly diverse. None of the V isotypes examined (i.e. V8.2, V8.5 or V10) was used by a major population of the -TCR-positive T cells. A more detailed, quantitative analysis of individual infiltrate compartments revealed, however, a preferential accumulation of V8.2-positive T cells within the parenchyma. In contrast, perivascular infiltrating cells used V genes randomly. Our results confirm first that activated T lymphocytes enter the brain rapidly irrespective of their antigen specificity. Second, the data show that most of the perivascular infiltrate T cells in the acute EAE lesion are host-derived, recruited presumably from the recirculating T cell pool, while the encephalitogenic, V8.2-positive T cells preferentially persist within the parenchyma.Abbreviations EAE experimental autoimmune encephalomyelitis - MBP myelin basic protein - TCL T cell line Supported by the Brazilian Research Council (CNPq)     

Immunohistological study of senile brains by using a monoclonal antibody recognizing β amyloid precursor protein: significance of granular deposits in relation with senile plaques

Summary Immunochemical analyses revealed that a monclonal antibody Am-3 recognized amyloid precursor protein (APP) in senile plaques extracted from Alzheimer's brain, but did not recognize amyloid protein. Immunohistochemically, however, the staining pattern of Am-3 in frozen section of Alzheimer's brain was almost the same with that of rabbit polyclonal antibody to amyloid peptide which could recognize both amyloid protein and APP. In other words, APP was present in senile plaques of various types, cerebrovascular amyloid and granular deposits. The granular deposits were 5–10 m in size and laminarily distributed in the 1st, 3rd and 4th layers of cerebral cortex. They were especially abundant in 1st and 4th layers where senile plaques were usually fewer in number. Although the distribution in the cerebral cortex was different between the senile plaques and the granular deposits, the number of the granular deposits was well correlated with that of senile plaques. The granular deposits were negative in Congo-red birefringence, but contained amyloid protein as well as APP fragment judging from positive staining by both Am-3 and polyclonal antibody to synthetic amyloid peptide. Thus, they could be regarded as pre-amyloid.     

Analysis of TGF-β2 and TGF-β3 expression in the hydrocephalic H-Tx rat brain

Introduction Transforming growth factor- (TGF-) is an important cytokine with modulatory actions in the nervous system. The development of hydrocephalus in mouse models resulting from the overexpression of TGF-1 has previously been described, but the mechanism by which this occurs remains obscure.Methods In order to evaluate the role of TGF- in hydrocephalus, we used SYBR Green I-based real-time quantitative RT-PCR method and Western blot analysis to analyze the TGF-2 and TGF-3 mRNA and protein expressions in the cerebral cortex of the H-Tx rat, a model of congenital hydrocephalus.Results The hydrocephalic H-Tx rat expressed significantly higher TGF-3 levels than their normal siblings (p<0.01) at 7 and 14 days of age. This difference became insignificant when analyzed at 21 days of age. On the other hand, such a difference has not been observed in the TGF-2 levels in the hydrocephalic H-Tx rat.Conclusions These results suggest that TGF-2 and TGF-3 expression may be modulated differently in the hydrocephalus, and TGF-3 may contribute to the development of hydrocephalus in this rat model.     

Neuroleptics andβ-carbolines displace (3H)imipramine from its binding sites in human and rat tissues

Summary Most investigations dealing with the pharmacological characterization of (³H)imipramine binding sites focus on tricyclic antidepressants (TCA). This approach seemed to be justified since imipramine belongs to that chemical group.Langer and coworkers, however, introduced a tetrahydro--carboline (THC) as a possible endogenous ligand. Thus, the high affinity of imipramine towards the binding sites might not be due to its special chemical structure but due to its tricyclic nature. In the present paper the structure-activity-relationships of neuroleptics and-carbolines were investigated and compared with that of tricyclic antidepressants.Among the tricyclic neuroleptics those with an electron attracting substituent (-Cl) exerted highest affinity. The effect was attenuated by a long, cyclic side chain. The affinity of tricyclic neuroleptics was only slightly weaker than that of 6-Meo-THC the suggested endogenous ligand. The experiments with other THCs supported the observation that an electron attracting substituent increases the affinity of a compound to the (³H)imipramine binding sites.Comparison of the binding characteristics of (³H)imipramine to membranes of human brain and thrombocytes as well as those of rat brain and thrombocytes revealed no differences among both species. Furthermore, the displacing potencies of neuroleptics were very similar with only slightly more activity in human tissue.As a methodological aspect the applicability of the Lowry method to determine the protein concentration is discussed.     

Histochemische Untersuchungen zur Verteilung und Aktivität hydrolytischer Enzyme in Gliomen

Zusammenfassung Es wird über Aktivität und Verteilung der -Glucuronidase, -Galaktosidase, -Glucosidase und Arylsulfatase in 49 Gliomen berichtet. Die höchste Aktivität in den Tumorzellen weisen die Glykosidasen auf. Mit zunehmender Malignität der Tumorart ist eine Zunahme der Glykosidasenreaktion festzustellen. Alle untersuchten Enzyme sind infolge Diffusion in zerfallenden Markscheiden und ihren Fragmenten nachweisbar.

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Summary Activities and distribution patterns of -glucuronidase, -galactosidase, -glucosidase and arylsulfatase were demonstrated histochemically in 49 gliomas. The activities of the glycosidases were higher than that of the sulfatase, and also higher in malignant tumors than in benign ones. The enzymes tested are seen within damaged and disintegrating portions of the myelin sheath.

     

Histochemische Enzymnachweise in den neurosekretorischen Kernen der Ratte

Zusammenfassung An den Gehirnen von 36 weiblichen Ratten wurden die Enzyme Cytochromoxydase, Lactat-, Succinodehydrogenase, DPNH- und TPNH-Diaphose, sowie -Glucuronidase, -Galactosidase, -Glucosidase und Arylsulfatase in den neurosekretorischen Kernen untersucht.SDH und CyO zeigten eine niedrige Aktivität, während LDH, DPNH-Di und TPNH-Di deutlich nachweibsar waren.Die Reaktionen beim Glykosidennachweis fielen nur schwach aus, ein sicherer Nachweis der Arylsulfatase gelang nicht.

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Histochemical demonstration of enzymes in neurosecretory nuclei of the rat

Summary The enzymes cytochromoxydase, lactic-, succino-dehydrogenase, DPNH- and TPNH-diaphorase as well as -glucuronidase, -galactoidases, -glucosidase and arylsulfatase were analysed in the paraventricular and supraoptic nucleus of the brains of 36 female rats.SDH and CyO showed a lower activity while LDH, DPNH-di and TPNH-di could be proved distinctly.On proving glycosidases the reactions were only moderate. A certain proof of arylsulfatase could not be furnished.

     

Amyloid β peptide 1–42 highly correlates with capillary cerebral amyloid angiopathy and Alzheimer disease pathology

Recent studies reported both positive [Thal et al. (2003) J Neuropathol Exp Neurol 62:1287–1301] and negative [Tian et al. (2003) Neurosci Lett 352:137–140] correlations between cerebral amyloid angiopathy (CAA) and Alzheimers disease (AD) pathology. We have recently shown high correlations between neuritic AD pathology and amyloid peptide (A) deposits in the capillary/pericapillary compartment (CapCAA) with only low correlations to general CAA (non-capillary). We have now studied the relationship between CapCAA and AD pathology with respect to the distribution of A40 and 42 in the frontal cortex of 100 human postmortem brains from both male and female, demented and non-demented patients (mean age ± SD 84.3±9.3 years). Using polyclonal antibodies to A40 and 42, capillary and plaques positivity were assessed semiquantiatively on a four-point scale. A42 deposits in capillaries correlated highly with both A42 deposits in plaques and morphological AD criteria (CERAD, Braak stages, and NIA-Reagan-Institute criteria), while only a low correlation with CAA was observed. A40 deposits in capillaries differed morphologically from A42 ones: they were limited to capillary walls, were significantly less frequent in both capillaries and plaques compared to A42 (P<0.01), and showed a low correlation with morphological AD criteria (P<0.05) and general CAA (P<0.01). By contrast, A42 deposits were seen in the glia limitans rather than in capillary walls themselves, and showed high correlation with morphological AD criteria (P<0.01). These data indicate that CapCAA is characterized by A42 deposits in pericapillary spaces or in the glia limitans. A low correlation between CAA and CapCAA, but high correlations between morphological AD criteria and CapCAA suggest different pathomechanisms for both types of CAA, and a close relation between CapCAA and AD pathology (both neuritic and plaque type). These data support the concept of a neuronal origin of A via drainage from interstitial fluid from the central nervous system along basement membranes to capillaries.List of Abbreviations AD Alzheimer disease - A beta amyloid peptide - A 40/42 CapS score of deposits of A 1–40/42 in capillaries - A 40/42 C number of A 1–40/42 positive cortical vessels - A 40/42 PS score of deposits of A 1–40/42 in plaques - A 40/42 TS total score of A 1–40/42 deposits - A 40/42 Csev severity of A 1–40/42 affection of cortical vessels - A 40/42 CS A 1–40/42 cortical score - A 40/42 L percentage of A 40/42 positive leptomeningeal vessels - A 40/42 Lsev severity of A 40/42 affection of leptomeningeal vessels - A 40/42 LS A 40/42 leptomeningeal score - ACTS A cortical total score - ALTS A leptomeningeal total score - CAA cerebral amyloid angiopathy - CAATS CAA total score - CapCAA capillary CAA - CERAD Consortium to Establish a Registry of Alzheimers Disease - NFT neurofibrillary tangle - NIA National Institute of Aging - NIA-RI National Institute of Aging and Reagan Institute - NP neuritic plaque - SP senile plaque - TS total scoreAn erratum to this article can be found at     

Immunohistochemical study on the distribution of α and β subunits of S-100 protein in brain tumors

Summary The immunohistochemical distribution of and subunits of S-100 protein (S-100, S-100, respectively) in 138 cases of human brain tumors was investigated by the avidin-biotin immunoperoxidase method. Brain tumors can be divided into four groups: group 1 [S-100 (+) and/or S-100 (+)]; astrocytoma, glioblastoma, ependymoma, subependymoma, oligodendroglioma, choroid plexus papilloma, gangliocytoma, meningioma, chordoma, malignant melanoma. Group 2 [S-100 (+) and S-100 (-)]; pineoblastoma, pituitary adenoma, craniopharyngioma, rhabdomyosarcoma. Group 3 [S-100 (-) and S-100 (+)]; acoustic Schwannoma. Group 4 [S-100 (-) and S-100 (-)]; medulloblastoma, malignant lymphoma, germinoma. The S-100 immunoreactivity pattern in brain tumors was similar to those obtained using conventional anti-S-100 protein sera. In the first group of brain tumors both the number of positively stained tumor cells and the staining intensity were generally greater for S-100 than for S-100 with a few exceptions including one gemistocytic astrocytoma, one subependymoma, one malignant melanoma, and some cases of glioblastomas. As to the relationship between malignancy and S-100 protein in glioma, S-100 immunoreactivity decreased according to degree of malignancy, while that of S-100 varied, suggesting a heterogeneity of tumor cells in glioblastomas. Immunostaining for S-100 and S-100 might become a useful diagnostic procedure in brain tumors and may give us more detailed and precise data of S-100 protein in brain tumors.     

Adrenergic receptors in the forehead microcirculation

The presence of - and -adrenoceptors in the forehead microcirculation was investigated in 49 healthy subjects. Local vascular responses to noradrenaline, isoprenaline and adrenergic antagonists, administered transcutaneously by iontophoresis, were monitored via laser Doppler flowmetry. Iontophoresis of the -adrenergic antagonist phentolamine induced a persistent increase in skin blood flow, whereas iontophoresis of saline induced a minor increase in skin blood flow which subsided rapidly. Skin blood flow increased moderately after the iontophoresis of the -adrenergic antagonist propranolol. Pretreatment of the experimental site with phentolamine blocked the normal vasoconstrictor response to noradrenaline, and unmasked a minor vasodilator component of response in some subjects. Iontophoresis of the -adrenergic agonist isoprenaline induced dose-dependent vasodilatation which was antagonised by propranolol. These findings indicate that -adrenoceptors in the forehead microcirculation normally mediate a vasoconstrictor response to iontophoretically-applied noradrenaline. In addition, -adrenoceptors appear to mediate a minor vasodilator component of response.     

Differential effects of “Advanced glycation endproducts” and β-amyloid peptide on glucose utilization and ATP levels in the neuronal cell line SH-SY5Y

Summary. -amyloid peptide (A) and Advanced glycation endproducts (AGEs) are components of the senile plaques in Alzheimers disease patients. It has been proposed that both AGEs and A exert many of their effects, which include the upregulation of pro-inflammatory cytokines, through RAGE (receptor for advanced glycation endproducts). To investigate whether A and AGEs cause similar or identical effects on cell survival and energy metabolism, we have compared the effects of a model-AGE and A on cell viability, ATP level, glucose consumption and lactate production in the neuroblastoma cell line SH-SY5Y. The results show that AGEs and A increase glucose consumption and decrease ATP levels in a dose dependent manner. Furthermore, both compounds decrease mitochondrial activity measured by the MTT assay. However, only AGEs decrease the number of cells and significantly increase lactate production. These data indicate that both AGEs and A can cause differential disturbances in neuronal metabolism, which may contribute to the pathophysiological findings in Alzheimers disease. However, their signalling pathways are apparently quite distinct, a fact which should stimulate a more detailed investigation in this field, e.g. for the purpose of a rational design of potential neuroprotective RAGE antagonists.     

<Superscript>123</Superscript>I-β-CIT binding and recovery from depression

Abstract. Eighteen depressive outpatients were investigated using single-photon emission computerized tomography (SPECT) with a high-affinity dopamine (DA) and serotonin transporter (SERT) specific radioligand, ¹²³I-labeled -CIT (2-carbomethoxy-3-(4-iodophenyl)-tropane). The patients were tested at the beginning of the study and on follow-up after six months. The severity of depression was evaluated using the 17-item Hamilton Rating Scale of Depression (HRSD). Eight of the eighteen patients had an HRSD score below the median (12 points) on follow-up, and they had a significantly greater increase in ¹²³I--CIT binding in the midbrain region compared with those patients who did not recover (ANCOVA: F = 8.12; df = 1, 14; p = 0.013). These results indicate that recovery from depression is associated with an increase in ¹²³I--CIT binding in the midbrain.     

Early detection of axonal injury after human head trauma using immunocytochemistry for β-amyloid precursor protein

Severe non-missile head injury commonly results in a form of brain damage known as diffuse axonal injury (DAI). The histological diagnosis of DAI is made by silver staining for the presence of axonal retraction balls. This feature takes about 24 h to develop and does not allow for the early histological diagnosis of DAI. We have used immunocytochemistry for the -amyloid precursor protein (APP) as a marker for axonal injury in formalin-fixed, paraffin-embedded sections of human brain. Axonal APP immunoreativity was present in all cases which had survived for 3 h or more. This was true even where the degree of head injury did not appear to be severe, supporting the theory that DAI is a severe form of a more common phenomenon of axonal injury which occurs after cerebral trauma. APP immunoreactivity was also found in some non-head injured cases and so cannot be considered to be a specific marker for trauma. The results show that APP immunocytochemistry may be useful in the detection of traumatic axonal injury in its early stages, before the formation of axonal retraction balls, provided care is taken to exclude other causes of such immunoreactivity.Supported by the Home Office Policy Advisory Board for Forensic Pathology (UK)     

β-CIT SPECT demonstrates blockade of 5HT-uptake sites by citalopram in the human brain in vivo

Summary The cocaine analogue 2--carbomethoxy-3--(4-iodophenyl)-tropane (-CIT) is a potent ligand for both dopamine- and serotonin uptake sites which in its¹²³I labeled form can be used for single photon emission computerized tomography (SPECT). It was demonstrated previously by SPECT-studies in non-human primates that¹²³I--CIT binds to dopamine transporters in the striatum and to serotonin transporters in hypothalamus and midbrain. The aim of the present study was to compare¹²³I--CIT binding in the brain stem of normal controls and a group of subjects under treatment with the selective serotonin reuptake inhibitor (SSRI) citalopram.¹²³I--CIT- SPECT was performed in 12 depressed patients under 20 mg (n=5), 40 mg (n=6) and 60 mg (n=1) citalopram daily, in one untreated depressed patient and in 11 controls at regular time intervals up till 24 hours p.inj. A highly significant reduction of -CIT binding was found in an area including mesial thalamus, hypothalamus, midbrain and pons in patients under citalopram compared to controls (44.1 ± 14.4 vs. 82.3 ± 18.6 cpm's/mCi × kg body weight; specific binding 4 hrs p.inj.; p=0.0001). No differences were seen between the high and low dose group and no changes were found in the striatum.¹²³I--CIT binding in the brain stem and striatum in one untreated depressed patient fell within the range of control values.To our knowledge this is the first report directly demonstrating the effect of a selective serotonin uptake inhibitor in the brain in humans in vivo. SPECT measurements of serotonin uptake sites in patients with depression and other psychiatric disorders might provide better insights into the pathophysiology of these disorders and into mechanisms of drug action.