Complete genome sequence of the model actinomycete Streptomyces coelicolor A3(2)

Streptomyces coelicolor is a representative of the group of soil-dwelling, filamentous bacteria responsible for producing most natural antibiotics used in human and veterinary medicine. Here we report the 8,667,507 base pair linear chromosome of this organism, containing the largest number of genes so far discovered in a bacterium. The 7,825 predicted genes include more than 20 clusters coding for known or predicted secondary metabolites. The genome contains an unprecedented proportion of regulatory genes, predominantly those likely to be involved in responses to external stimuli and stresses, and many duplicated gene sets that may represent 'tissue-specific' isoforms operating in different phases of colonial development, a unique situation for a bacterium. An ancient synteny was revealed between the central 'core' of the chromosome and the whole chromosome of pathogens Mycobacterium tuberculosis and Corynebacterium diphtheriae. The genome sequence will greatly increase our understanding of microbial life in the soil as well as aiding the generation of new drug candidates by genetic engineering.

The genome sequence of Schizosaccharomyces pombe

We have sequenced and annotated the genome of fission yeast (Schizosaccharomyces pombe), which contains the smallest number of protein-coding genes yet recorded for a eukaryote: 4,824. The centromeres are between 35 and 110 kilobases (kb) and contain related repeats including a highly conserved 1.8-kb element. Regions upstream of genes are longer than in budding yeast (Saccharomyces cerevisiae), possibly reflecting more-extended control regions. Some 43% of the genes contain introns, of which there are 4,730. Fifty genes have significant similarity with human disease genes; half of these are cancer related. We identify highly conserved genes important for eukaryotic cell organization including those required for the cytoskeleton, compartmentation, cell-cycle control, proteolysis, protein phosphorylation and RNA splicing. These genes may have originated with the appearance of eukaryotic life. Few similarly conserved genes that are important for multicellular organization were identified, suggesting that the transition from prokaryotes to eukaryotes required more new genes than did the transition from unicellular to multicellular organization.

Roles of the metallothionein family of proteins in the central nervous system

Metallothioneins (MTs) constitute a family of proteins characterized by a high heavy metal [Zn(II), Cu(I)] content and also by an unusual cysteine abundance. Mammalian MTs are comprised of four major isoforms designated MT-1 trough MT-4. MT-1 and MT-2 are expressed in most tissues including the brain, whereas MT-3 (also called growth inhibitory factor) and MT-4 are expressed predominantly in the central nervous system and in keratinizing epithelia, respectively. All MT isoforms have been implicated in disparate physiological functions, such as zinc and copper metabolism, protection against reactive oxygen species, or adaptation to stress. In the case of MT-3, an additional involvement of this isoform in neuromodulatory events and in the pathogenesis of Alzheimer's disease has also been suggested. It is essential to gain insight into how MTs are regulated in the brain in order to characterize MT functions, both in normal brain physiology, as well as in pathophysiological states. The focus of this review concerns the biology of the MT family in the context of their expression and functional roles in the central nervous system.

Heterologous sequences greatly affect foreign gene expression in tobacco mosaic virus-based vectors

A series of tobacco mosaic virus (TMV)-based hybrid vectors for transient gene expression were constructed with similar designs but differing in the source of heterologous tobamovirus sequence: Odontoglossum ringspot virus, tobacco mild green mosaic virus variants U2 and U5, tomato mosaic virus, and sunn-hemp mosaic virus. These vectors contained a heterologous coat protein subgenomic mRNA promoter and coat protein open reading frame (ORF) and either TMV or heterologous 3' nontranslated region. The foreign ORF, from the jellyfish green fluorescent protein (GFP) gene, was transcribed from the native TMV coat protein subgenomic mRNA promoter, which extended into the coat protein ORF. The presence of an in-frame stop codon within the GFP mRNA leader and the choice of sequence of GFP ORFs substantially affected translational efficiency. However, the major regulatory component of gene expression in these vectors appeared to be transcriptional rather than translational. There was an inverse relationship between expression of GFP and the heterologous coat protein genes that was reflected in accumulation of the respective mRNAs and proteins. The most effective vector in this series (30B) contained sequences encoding the coat protein subgenomic mRNA promoter, coat protein ORF, and 3' nontranslated region from tobacco mild green mosaic virus U5. Expressed from 30B, GFP accumulated up to 10% of total soluble protein in leaves.

Zidovudine and the natural history of the acquired immunodeficiency syndrome

BACKGROUND AND METHODS

We sought to describe the trends in survival from 1983 to 1989 among persons with the acquired immunodeficiency syndrome (AIDS) and to examine the relative effects on the natural history of AIDS of zidovudine use and demographic and clinical characteristics. This longitudinal, observational, population-based study used data from the Maryland Human Immunodeficiency Virus Information System, a data base that links information from the Maryland AIDS Registry with data on public and private health care claims, vital statistics, and hospital, long-term care, and ambulatory care records.

RESULTS

The median survival after diagnosis among persons with AIDS (n = 1028) was 140 days longer for those given their diagnoses between 1987 and 1989 than for those given their diagnoses between 1983 and 1985 (450 vs 310 days). Among the 714 persons in whom AIDS was diagnosed after April 1987 (when zidovudine became available), two-year survival was greater among men than women (P less than 0.03), among persons less than 45 years old than among older persons (P less than 0.001), among non-Hispanic whites than among minorities (P less than 0.001), and among persons whose category of human immunodeficiency virus transmission was homosexual contact than among those with heterosexual, transfusion-related, or less common modes of transmission (P less than 0.02). In all the analyses the groups with the longer survival were more likely to have received zidovudine. The median survival among those who received zidovudine was 770 days, as compared with 190 days among those who never received the drug (P less than 0.001). By proportional-hazards analysis, zidovudine therapy was the factor most strongly associated with improved survival.

CONCLUSIONS

For Maryland residents with AIDS there has been an improvement in survival since 1987. Zidovudine therapy and perhaps other aspects of care associated with it have contributed substantially to the improved survival.

Synthesis of enantiopure trans-3,4-disubstituted piperidines. An enantiodivergent synthesis of (+)- and (-)-paroxetine

Reaction of (R)-phenylglycinol with methyl 5-oxopentanoate gave either bicyclic lactam cis-1 (the kinetic product) or its isomer trans-1 (under equilibrating conditions) as the major products, which were converted to the corresponding (cis or trans) unsaturated lactams 4 and 5. On treatment with lithium alkyl (or aryl) cyanocuprates, these chiral building blocks undergo conjugate addition to give enantiopure trans-3,4-substituted 2-piperidone derivatives in high yield and stereoselectivity. The synthetic potential of this transformation is illustrated by the synthesis of (+)-femoxetine and the two enantiomers of the known antidepressant paroxetine.

Impaired inflammatory response and increased oxidative stress and neurodegeneration after brain injury in interleukin-6-deficient mice

In order to determine the role of the neuropoietic cytokine interleukin-6 (IL-6) during the first 3 weeks after a focal brain injury, we examined the inflammatory response, oxidative stress and neuronal survival in normal and interleukin-6-deficient (knockout, IL-6KO) mice subjected to a cortical freeze lesion. In normal mice, the brain injury was followed by reactive astrogliosis and recruitment of macrophages from 1 day postlesion (dpl), peaking at 3-10 dpl, and by 20 dpl the transient immunoreactions were decreased, and a glial scar was present. In IL-6KO mice, the reactive astrogliosis and recruitment of macrophages were decreased throughout the experimental period. The expression of the antioxidant and anti-apoptotic factors metallothionein I+II (MT-I+II) was increased prominently by the freeze lesion, but this response was significantly reduced in the IL-6 KO mice. By contrast, the expression of the antioxidants Cu/Zn-superoxide dismutase (Cu/Zn-SOD), Mn-SOD, and catalase remained unaffected by the IL-6 deficiency. The lesioned mice showed increased oxidative stress, as judged by malondialdehyde (MDA) and nitrotyrosine (NITT) levels and by formation of inducible nitric oxide synthase (iNOS). IL-6KO mice showed higher levels of MDA, NITT, and iNOS than did normal mice. Concomitantly, in IL-6KO mice the number of apoptotic neurons was significantly increased as judged by TUNEL staining, and regeneration of the tissue was delayed relative to normal mice. The changes in neuronal tissue damage and in brain regeneration observed in IL-6KO mice are likely caused by the IL-6-dependent decrease in MT-I+II expression, indicating IL-6 and MT-I+II as neuroprotective factors during brain injury.

Enhanced seizures and hippocampal neurodegeneration following kainic acid-induced seizures in metallothionein-I + II-deficient mice

Metallothioneins (MTs) are major zinc binding proteins in the CNS that could be involved in the control of zinc metabolism as well as in protection against oxidative stress. Mice lacking MT-I and MT-II (MT-I + II deficient) because of targeted gene inactivation were injected with kainic acid (KA), a potent convulsive agent, to examine the neurobiological importance of these MT isoforms. At 35 mg/kg KA, MT-I + II deficient male mice showed a higher number of convulsions and a longer convulsion time than control mice. Three days later, KA-injected mice showed gliosis and neuronal injury in the hippocampus. MT-I + II deficiency decreased both astrogliosis and microgliosis and potentiated neuronal injury and apoptosis as shown by terminal deoxynucleotidyl transferase-mediated in situ end labelling (TUNEL), detection of single stranded DNA (ssDNA) and by increased interleukin-1beta-converting enzyme (ICE) and caspase-3 levels. Histochemically reactive zinc in the hippocampus was increased by KA to a greater extent in MT-I + II-deficient compared with control mice. KA-induced seizures also caused increased oxidative stress, as suggested by the malondialdehyde (MDA) and protein tyrosine nitration (NITT) levels and by the expression of MT-I + II, nuclear factor-kappaB (NF-kappaB), and Cu/Zn-superoxide dismutase (Cu/Zn-SOD). MT-I + II deficiency potentiated the oxidative stress caused by KA. Both KA and MT-I + II deficiency significantly affected the expression of MT-III, granulocyte-macrophage colony stimulating factor (GM-CSF) and its receptor (GM-CSFr). The present results indicate MT-I + II as important for neuron survival during KA-induced seizures, and suggest that both impaired zinc regulation and compromised antioxidant activity contribute to the observed neuropathology of the MT-I + II-deficient mice.

Interleukin-6 deficiency reduces the brain inflammatory response and increases oxidative stress and neurodegeneration after kainic acid-induced seizures

The role of interleukin-6 in hippocampal tissue damage after injection with kainic acid, a rigid glutamate analogue inducing epileptic seizures, has been studied by means of interleukin-6 null mice. At 35mg/kg, kainic acid induced convulsions in both control (75%) and interleukin-6 null (100%) mice, and caused a significant mortality (62%) only in the latter mice, indicating that interleukin-6 deficiency increased the susceptibility to kainic acid-induced brain damage. To compare the histopathological damage caused to the brain, control and interleukin-6 null mice were administered 8.75mg/kg kainic acid and were killed six days later. Morphological damage to the hippocampal field CA1-CA3 was seen after kainic acid treatment. Reactive astrogliosis and microgliosis were prominent in kainic acid-injected normal mice hippocampus, and clear signs of increased oxidative stress were evident. Thus, the immunoreactivity for inducible nitric oxide synthase, peroxynitrite-induced nitration of proteins and byproducts of fatty acid peroxidation were dramatically increased, as was that for metallothionein I+II, Mn-superoxide dismutase and Cu/Zn-superoxide dismutase. In accordance, a significant neuronal apoptosis was caused by kainic acid, as revealed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling and interleukin-1beta converting enzyme/Caspase-1 stainings. In kainic acid-injected interleukin-6 null mice, reactive astrogliosis and microgliosis were reduced, while morphological hippocampal damage, oxidative stress and apoptotic neuronal death were increased. Since metallothionein-I+II levels were lower, and those of inducible nitric oxide synthase higher, these concomitant changes are likely to contribute to the observed increased oxidative stress and neuronal death in the interleukin-6 null mice. The present results demonstrate that interleukin-6 deficiency increases neuronal injury and impairs the inflammatory response after kainic acid-induced seizures.

Evidence that the pituitary-adrenal axis does not cross-adapt to stressors: comparison to other physiological variables

The effects of previous chronic immobilization stress on the physiological responses of male rats to a novel chronic stressor (shock) were studied. Previous chronic exposure to immobilization reduced adrenocorticotropin (ACTH) and lactate responses to acute immobilization stress without altering the response to a novel acute stressor (tail shock). When subjected to chronic tail shock, body weight inhibition caused by chronic shock was greater in the rats not previously exposed to chronic immobilization, which suggests that there is cross-adaptation between different stressors. However, adrenocorticotropin adaptation to chronic shock was impaired by previous chronic immobilization. These data indicate that the existence of cross-adaptation to stressors might depend on the variable measured, the central nervous system pathways controlling the pituitary-adrenal axis being, apparently, resistant to cross-adaptation. This lack of cross-adaptation at certain levels can assure the maintenance of an adequate response to unknown environmental stimuli.

ClC-3 is a fundamental molecular component of volume-sensitive outwardly rectifying Cl- channels and volume regulation in HeLa cells and Xenopus laevis oocytes

Volume-sensitive osmolyte and anion channels (VSOACs) are activated upon cell swelling in most vertebrate cells. Native VSOACs are believed to be a major pathway for regulatory volume decrease (RVD) through efflux of chloride and organic osmolytes. ClC-3 has been proposed to encode native VSOACs in Xenopus laevis oocytes and in some mammalian cells, including cardiac and vascular smooth muscle cells. The relationship between the ClC-3 chloride channel, the native volume-sensitive osmolyte and anion channel (VSOAC) currents, and cell volume regulation in HeLa cells and X. laevis oocytes was investigated using ClC-3 antisense. In situ hybridization in HeLa cells, semiquantitative and real-time PCR, and immunoblot studies in HeLa cells and X. laevis oocytes demonstrated the presence of ClC-3 mRNA and protein, respectively. Exposing both cell types to hypotonic solutions induced cell swelling and activated native VSOACs. Transient transfection of HeLa cells with ClC-3 antisense oligonucleotide or X. laevis oocytes injected with antisense cRNA abolished the native ClC-3 mRNA transcript and protein and significantly reduced the density of native VSOACs activated by hypotonically induced cell swelling. In addition, antisense against native ClC-3 significantly impaired the ability of HeLa cells and X. laevis oocytes to regulate their volume. These results suggest that ClC-3 is an important molecular component underlying VSOACs and the RVD process in HeLa cells and X. laevis oocytes.

Metallothionein treatment reduces proinflammatory cytokines IL-6 and TNF-alpha and apoptotic cell death during experimental autoimmune encephalomyelitis (EAE)

Experimental autoimmune encephalomyelitis (EAE) is an animal model for the human autoimmune disease multiple sclerosis (MS). Proinflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) are considered important for induction and pathogenesis of EAE/MS disease, which is characterized by significant inflammation and neuroglial damage. We have recently shown that the exogenous administration of the antioxidant protein zinc-metallothionein-II (Zn-MT-II) significantly decreased the clinical symptoms, mortality, and leukocyte infiltration of the CNS during EAE. However, it is not known how EAE progression is regulated nor how cytokine production and cell death can be reduced. We herewith demonstrate that treatment with Zn-MT-II significantly decreased the CNS expression of IL-6 and TNF-alpha during EAE. Zn-MT-II treatment could also significantly reduce apoptotic cell death of neurons and oligodendrocytes during EAE, as judged by using TUNEL and immunoreactivity for cytochrome c and caspases 1 and 3. In contrast, the number of apoptotic lymphocytes and macrophages was less affected by Zn-MT-II treatment. The Zn-MT-II-induced decrease in proinflammatory cytokines and apoptosis during EAE could contribute to the reported diminution of clinical symptoms and mortality in EAE-immunized rats receiving Zn-MT-II treatment. Our results demonstrate that MT-II reduces the CNS expression of proinflammatory cytokines and the number of apoptotic neurons during EAE in vivo and that MT-II might be a potentially useful factor for treatment of EAE/MS.

Trigger point evaluation in migraine patients: an indication of peripheral sensitization linked to migraine predisposition?

Although migraine is a neurovascular disorder, both scalp tenderness and referred pain have been observed in migraine patients. The present study was carried out to investigate the presence of trigger points eliciting referred pain in 98 migraine patients and in 32 healthy subjects. Trigger points were found in 92 (93.9%) migraineurs and in nine (29%) controls (P < 0.0001). The number of individual migraine trigger points varied from zero to 14 (modal number: 4), and was found to be related to both the frequency of migraine attacks (P < 0.0001), and the duration of the disease (P = 0.017). About 74% of the total detected trigger points were found in temporal and/or suboccipital areas; other locations were mainly found in patients showing more than four trigger points. Trigger point palpation provoked a migraine attack in 30 (30.6%) patients. Pericraneal allodynia was found in 15 (15.3%) patients. These data indicate that nociceptive peripheral sensitization is a usual finding in migraine, and that central sensitization can develop in patients with frequent attacks and long-lasting disease. Trigger points' detection in migraine patients could be useful when applying therapies like acupuncture, needling or botulinum toxin injections directed to reduce peripheral sensitization.

Prescribing of psychotropic medication by primary care physicians and psychiatrists

This study investigates the prescribing of psychotropic medications by primary care physicians and psychiatrists using the National Ambulatory Medical Care Survey database. Results indicate that primary care practitioners provide a larger percentage of psychotropic drug visits than psychiatrists in every psychotropic class except for those patients prescribed lithium. In addition, the two provider groups differed in the relative proportions of the classes of psychotropic drugs prescribed. Primary care physicians prescribed anxiolytics most frequently, while psychiatrists prescribed antidepressants most often. Finally, in all therapeutic classes, when a psychotropic medication was prescribed, psychiatrists typically provided a mental health diagnosis, while primary care physicians did not.

Metallothionein is a component of exocrine pancreas secretion: implications for zinc homeostasis

Using transgenic mice that overexpress metallothionein-I (MT-I) and zinc-induced normal and transgenic animals, we have explored the localization of MT in the pancreas. Light-level immunocytochemistry demonstrated MT in acinar cells but not islet cells. Immunolabeling also revealed the presence of MT in pancreatic ducts, suggesting that it is released from acinar cells. Ultrastructural immunolocalization showed that MT was cytoplasmic, and no MT immunoreactivity was detected in lumens of the vesicular secretory pathway. Secreted pancreatic juice was collected from pilocarpine-stimulated mice and assayed for MT by a 109Cd-labeled hemoglobin-exchange assay and by radioimmunoassay. Both methods revealed high (> 1,000 ng/ml) levels of MT in the stimulated secretion. The level of MT in pancreatic juice from transgenic mice was only slightly (2-fold) increased despite dramatic overexpression of MT-I in the pancreas (> 20-fold). In contrast, zinc induction of MT significantly increased MT by 5- to 10-fold in the pancreatic juice, in normal and transgenic mice. These data indicate that MT is released from pancreatic acinar cells but not by the classical vesicular secretory pathway. In addition, MT levels in pancreatic juice are regulated by zinc, suggesting a physiological role of the pancreas in metal homeostasis.

Protein kinase A activity is required for the budding of constitutive transport vesicles from the trans-Golgi network

We have examined the role played by protein kinase A (PKA) in vesicle-mediated protein transport from the trans-Golgi network (TGN) to the cell surface. In vivo this transport step was inhibited by inhibitors of PKA catalytic subunits (C-PKA) such as the compound known as H89 and a myristoylated form of the inhibitory peptide sequence contained in the thermostable PKA inhibitor. Inhibition by H89 occurred at an early stage during the transfer of vesicular stomatitis virus G glycoprotein from the TGN to the cell surface. Reversal from this inhibition correlated with a transient increase in the number of free coated vesicles in the Golgi area. Vesicle budding from the TGN was studied in vitro using vesicular stomatitis virus-infected, permeabilized cells. Addition to this assay of C-PKA stimulated vesicle release while it was suppressed by PKA inhibitory peptide, H89, and antibody against C-PKA. Furthermore, vesicle release was decreased when PKA-depleted cytosol was used and restored by addition of C-PKA. These results indicate a regulatory role for PKA activity in the production of constitutive transport vesicles from the TGN.

Absence of microglia promotes diverse pathologies and early lethality in Alzheimer's disease mice

Microglia are strongly implicated in the development and progression of Alzheimer's disease (AD), yet their impact on pathology and lifespan remains unclear. Here we utilize a CSF1R hypomorphic mouse to generate a model of AD that genetically lacks microglia. The resulting microglial-deficient mice exhibit a profound shift from parenchymal amyloid plaques to cerebral amyloid angiopathy (CAA), which is accompanied by numerous transcriptional changes, greatly increased brain calcification and hemorrhages, and premature lethality. Remarkably, a single injection of wild-type microglia into adult mice repopulates the microglial niche and prevents each of these pathological changes. Taken together, these results indicate the protective functions of microglia in reducing CAA, blood-brain barrier dysfunction, and brain calcification. To further understand the clinical implications of these findings, human AD tissue and iPSC-microglia were examined, providing evidence that microglia phagocytose calcium crystals, and this process is impaired by loss of the AD risk gene, TREM2.

Altered central nervous system cytokine-growth factor expression profiles and angiogenesis in metallothionein-I+II deficient mice

To study the importance of metallothionein-I and -II (MT-I+II) for brain inflammation and regeneration, the authors examined normal and MT-I+II knock-out (MT-KO) mice subjected to a cortical freeze injury. Normal mice showed profound neurodegeneration, inflammation, and gliosis around the injury, which was repaired by 20 days postlesion (dpl). However, in MT-KO mice the lesion-associated inflammation was still present as late as 90 dpl. Scanning electron microscopy demonstrated that the number of capillaries was lower, and ultrastructural preservation of the lesioned parenchyma was poorer in MT-KO mice, suggesting an altered angiogenesis. To gain insight into the mechanisms involved, a number of cytokines and growth factors were evaluated. The number of cells expressing the proinflammatory cytokines IL-1beta, IL-6, and TNF-alpha was higher in MT-KO mice than in normal mice, which was confirmed by RNase protection analysis, whereas the number of cells expressing the growth factors bFGF, TGFbeta1, VEGF, and NT-3 was lower. Increased expression of proinflammatory cytokines could be involved in the sustained recruitment of CD-14+ and CD-34+ inflammatory cells and their altered functions observed in MT-KO mice. Decreases in trophic factors bFGF, TGFbeta1, and VEGF could mediate the decreased angiogenesis and regeneration observed in MT-KO mice after the freeze lesion. A role for MT-I+II in angiogenesis was also observed in transgenic mice expressing IL-6 under the control of the promoter of glial fibrillary acidic protein gene (GFAP-IL6 mice) because MT-I+II deficiency dramatically decreased the IL-6-induced angiogenesis of the GFAP-IL6 mice. In situ hybridization analysis indicated that the MT-III expression was not altered by MT-I+II deficiency. These results suggest that the MT-I+II isoforms have major regulatory functions in the brain inflammatory response to injury, especially in the angiogenesis process.

Fat emulsion for intravenous administration: clinical experience with intralipid 10%

A 10% soybean oil emulsion (Intralipid 10%), used extensively in Europe for intravenous alimentation, has now been clinically evaluated in the United States. Controlled studies have shown that the soybean oil emulsion can be substituted for glucose to supply one-third to two-thirds of the total calories, and can be administered peripherally without significant vein irritation. Essential fatty acid deficiencies, frequently encountered in patients dependent on parenteral alimentation with fat-free solutions, are prevented and corrected by use of this preparation. Data on long-term tolerance to Intralipid 10% infusions are presented for 292 patients treated for more than 6,000 patient days. The soybean oil emulsion was usually well tolerated. Side effects were reported in two of 133 adults and 12 of 159 pediatric patients.

Metallothionein I+II expression and their role in experimental autoimmune encephalomyelitis

We examined the expression and roles of neuroprotective metallothionein-I+II (MT-I+II) in the rat CNS in experimental autoimmune encephalomyelitis (EAE), an animal model for the human autoimmune disease, multiple sclerosis (MS). EAE caused significant macrophage activation, T-lymphocyte infiltration, and astrogliosis in spinal cord, brain stem, and cerebellum, which peaked 14-18 days after immunization. The remission of symptoms and histopathological changes began at days 19-21 and were completed by days 30-40. MT-I+II expression was increased significantly in EAE infiltrates. In order to study the effects of increased MT levels, we administered Zn-MT-II intraperitoneally (i.p.) to rats during EAE. Clinically, Zn-MT-II treatment reduced the severity of EAE symptoms and mortality in a time- and dose-dependent manner. Histopathologically, Zn-MT-II increased reactive astrogliosis and decreased macrophages and T lymphocytes significantly in the CNS. In spleen sections, the number of macrophages both in control and EAE-sensitized rats was reduced by Zn-MT-II, while the number of lymphocytes remained unaltered by Zn-MT-II. Therefore, we suggest that MT-II has peripheral mechanisms of action on macrophages, while T lymphocytes are affected locally in the CNS. During EAE, oxidative stress was decreased by Zn-MT-II, which could contribute to the diminished clinical scores observed. None of the effects caused by Zn-MT-II could be attributable to the zinc content. These results suggest MT-I+II as potentially useful factors for the treatment of EAE/MS.

Primary cortical glial reaction versus secondary thalamic glial response in the excitotoxically injured young brain: astroglial response and metallothionein expression

In this study we have evaluated the primary astroglial reactivity to an injection of N-methyl-D-aspartate into the right sensorimotor cortex, as well as the secondary astroglial response in the thalamic ventrobasal complex, caused by the anterograde degeneration of descending corticothalamic fibres and/or target deprivation of the developing thalamic neurons. The astroglial response was evaluated from 4 h to 30 days post-lesion, by the immunocytochemical detection of the cytoskeletal proteins glial fibrillary acidic protein and vimentin, and the antioxidant and metal binding protein metallothionein I-II. In the lesioned cortex, hypertrophied reactive astrocytes showed increased glial fibrillary acidic protein labelling that correlated with a strong expression of vimentin and metallothionein I-II. Maximal astrocytic response was seen at one week post-lesion. The glial scar that formed later on remained positive for all astroglial markers until the last survival time examined. In contrast, in the anterogradely/retrogradely affected thalamus, the induced astroglial secondary response was not as prominent as in the cortex and was characteristically transitory, being undetectable by 14 days post-lesion. Interestingly, thalamic reactive astrocytes showed increased glial fibrillary acidic protein expression but no induction of vimentin and metallothionein I-II. In conclusion, in the young brain, the pattern of astroglial reactivity is not homogeneous and is strongly dependent on the grade of tissue damage: both in response to primary neuronal death and in response to retrograde/anterograde secondary damage, reactive astrocytes show hypertrophy and increased glial fibrillary acidic protein expression. However, astroglial vimentin and metallothionein I-II expression are only observed in areas undergoing massive neuronal death, where glial scar is formed.

Metallothionein (MT)-III: generation of polyclonal antibodies, comparison with MT-I+II in the freeze lesioned rat brain and in a bioassay with astrocytes, and analysis of Alzheimer's disease brains

Metallothionein-III is a low molecular weight, heavy-metal binding protein expressed mainly in the central nervous system. First identified as a growth inhibitory factor (GIF) of rat cortical neurons in vitro, it has subsequently been shown to be a member of the metallothionein (MT) gene family and renamed as MT-III. In this study we have raised polyclonal antibodies in rabbits against recombinant rat MT-III (rMT-III). The sera obtained reacted specifically against recombinant zinc-and cadmium-saturated rMT-III, and did not cross-react with native rat MT-I and MT-II purified from the liver of zinc injected rats. The specificity of the antibody was also demonstrated in immunocytochemical studies by the elimination of the immunostaining by preincubation of the antibody with brain (but not liver) extracts, and by the results obtained in MT-III null mice. The antibody was used to characterize the putative differences between the rat brain MT isoforms, namely MT-I+II and MT-III, in the freeze lesion model of brain damage, and for developing an ELISA for MT-III suitable for brain samples. In the normal rat brain, MT-III was mostly present primarily in astrocytes. However, lectin staining indicated that MT-III immunoreactivity was also present in microglia, monocytes and/or macrophages in the leptomeninges and lying adjacent to major vessels. In freeze lesioned rats, both MT-I+II and MT-III immunoreactivities increased in the ipsilateral cortex. The pattern of MT-III immunoreactivity significantly differed from that of MT-I+II, since the latter was evident in both the vicinity of the lesioned tissue and deeper cortical layers, whereas that of the former was located only in the deeper cortical layers. This suggests different roles for these MT isoforms, and indeed in a new bioassay measuring astrocyte migration in vitro, rMT-III promoted migration to a higher extent than MT-I+II. Thus, MT-III could not only affect neuronal sprouting as previously suggested, but also astrocyte function. Finally, MT-III protein levels of patients with Alzheimer's disease (AD) were, if anything, increased when compared with similarly aged control brains, which was in agreement with the significantly increased MT-III mRNA levels of AD brains.

Development of a competitive double antibody radioimmunoassay for rat metallothionein

A competitive double antibody radioimmunoassay (RIA) for rat metallothionein (MT) has been developed that has a detection limit of 100 pg and a range of 100 to 100000 pg. The antibody was raised in rabbits against rat MT-2 but it crossreacts equally with MT-1 and MT-2. However, when the assay is done in the presence of 2-mercaptoethanol the antibody is more specific for MT-2. Zn- and Cd- saturated MTs have similar responses in the assay. Addition of Cu(II) to Zn-MT (more than 6 mol Cu/mol MT) in non-reducing conditions modifies the response of the antibody, probably because of Cu(II) oxidation and later MT polymerization. Standard curves developed in the presence of cytosols from brain cortex, hypothalamus or liver did not differ from the standard curve, indicating the absence of interfering substances in the assay. Furthermore, serial dilutions of those cytosols paralleled the response of the standard curve, indicating that the response of the antibody was specific. For comparison, MT levels in some brain areas measured with the present RIA were compared with those measured with an established RIA. In addition, the expected effect of dexamethasone and stress on liver MT levels was clearly identified by this RIA. The results suggest that the present RIA can be used for quantitation of metallothionein.