Evidence from photosynthetic characteristics for the hybrid origin of Diplotaxis muralis from a C3-C4 intermediate and a C3 species.

Artificial hybridization studies have been carried out between plants with different photosynthetic types to study the genetic mechanism of photosynthetic types. However, there are only few reports describing the possibility of natural hybridization between plants with different photosynthetic types. A previous cytological and morphological study suggested that a cruciferous allotetraploid species, Diplotaxis muralis (L.) DC. (2n = 42), originated from natural hybridization between D. tenuifolia (L.) DC. (2n = 22) and D. viminea (L.) DC. (2n = 20). These putative parents have recently been reported to be a C (3)-C (4) intermediate and a C (3) species, respectively. If this hybridization occurred, D. muralis should have characteristics intermediate between those of the C (3)-C (4) intermediate and C (3) types. We compared leaf structures and photosynthetic characteristics of the three species. The bundle sheath (BS) cells in D. tenuifolia included many centripetally located chloroplasts and mitochondria, but those of D. viminea had only a few organelles. The BS cells in D. muralis displayed intermediate features between the putative parents. Glycine decarboxylase P protein was confined to the BS mitochondria in D. tenuifolia, but accumulated mainly in the mesophyll mitochondria in D. viminea. In D. muralis, it accumulated in both the BS and the mesophyll mitochondria. Values of CO (2) compensation point and its response to changing light intensity were also intermediate between the putative parents. These data support the theory that D. muralis was created by natural hybridization between species with different photosynthetic types.

Neuronal and glial advanced glycation end product [Nepsilon-(carboxymethyl)lysine]] in Alzheimer's disease brains.

The cellular distribution of an advanced glycation end product [Nepsilon-(carboxymethyl)lysine (CML)] in aged and Alzheimer's disease (AD) brains was assessed immunohistochemically. CML was localized in the cytoplasm of neurons, astrocytes, and microglia in both aged and AD brains. Glial deposition was far more marked in AD brains than in aged brains, and neuronal deposition was also increased. On electron microscopic immunohistochemistry, neuronal CML formed granular or linear deposits associated with lipofuscin, and glial deposits formed lines around the vacuoles. Neuronal and glial deposits were prominent throughout the cerebral cortex and hippocampus, but were sparse in the putamen, globus pallidus, substantia nigra, and cerebellum, with glial deposits being far more prominent in AD brains. The distribution of neuronal and glial deposits did not correspond with the distribution of AD pathology. The extent of CML deposits was inversely correlated with neurofibrillary tangle formation, particularly in the hippocampus. Most hippocampal pyramidal neurons with neurofibrillary tangles did not have CML, and most of the neurons with heavy CML deposits did not have neurofibrillary tangles. In the hippocampus, neuronal CML was prominent in the region where neuronal loss was mild. These observations suggest that CML deposition does not directly cause neurofibrillary tangle formation or neuronal loss in AD.

[Acute onset of tuberculous meningoencephalitis presenting with symmetric linear lesions in the bilateral thalamus: a case report].

A 18-year-old woman was admitted to our hospital because of high fever and headache. Nuchal stiffness was present, and a CSF examination showed lymphocyte-domonant pleocytosis and a decreased level of glucose. Although antibiotics, aciclovir and an antimycotic drug were administered, disturbance of consciousness, involuntary movements, and pyramidal tract signs appeared. Soon after the medications were changed to antituberculous medicines, the meningoencephalitis started to subside, and was finally cured. Judging from the clinical findings, the CSF findings, the effectiveness of antituberculous medicines, an elevated ADA level in CSF, and positive conversion in tuberculin tests, the final diagnosis was made as tuberculous meningoencephalitis. At the severest stage of the disease, a brain MRI showed symmetric, linear lesions without the effect of Gd-enhancement in the bilateral thalamus, which thereafter disappeared along with the healing of the illness. From all these things, we conclude that thalamic and other parenchymal lesions should be kept in mind in case of acute tuberculous meningoencephalitis.

Medial temporal atrophy and memory impairment in early stage of Alzheimer's disease: an MRI volumetric and memory assessment study.

Memory impairment and medial temporal lobe (MTL) involvement are the earliest and most prominent features of Alzheimer's disease (AD). A psychological assessment of memory function and an evaluation of the morphological changes in MTL structures, as found in the mild form of AD, are important for early diagnosis as well as for understanding the pathophysiology of the disease. In the present study, we aimed to evaluate correlations in these psychoanatomical changes in terms of the stage of AD. We performed MRI-based volumetric measurements of the MTL structure and neuropsychological tests, using MMSE and the Wechsler memory scale-revised (WMS-R), on 27 elderly normal subjects and 46 probable AD patients, and then checked for possible correlations between the volumetric measurements and memory dysfunction. The severity of the AD patients' condition was assessed by CDR scale. Each MTL structure decreased in volume with increasing severity of AD. In very early AD, the reduction in the amygdala volume was pronounced, while the hippocampal volumes were relatively unchanged. Neuropsychological scores also declined with increasing severity of AD. Scores on the main WMS-R subsets examined (verbal memory, visual memory, and delayed recall) decreased significantly in the very mild group, as compared with normal controls. The WMS-R test scores correlated significantly with the amygdala volumes in normal control subjects and very mild AD patients. Our findings suggest that MRI-based amygdaloid volumetric measurement provides a sensitive marker, and that the degeneration of the amygdala may begin very early in the course of AD.

Accelerated formation of N epsilon-(carboxymethyl) lysine, an advanced glycation end product, by glyoxal and 3-deoxyglucosone in cultured rat sensory neurons.

The formation of advanced glycation end products (AGEs) is associated with pathophysiological changes with aging and disease processes. In the neurodegeneration in Alzheimer's disease and other neurodegenerative diseases. AGEs are speculated to play a role in their pathogenesis. We provide the first evidence for the induction of AGEs in cultured neuronal cells. Glyoxal and 3-deoxyglucosone (3-DG), AGE precursors, induced N epsilon-(carboxymethyl) lysine (CML), a well characterized and major AGE structure, in cultured rat sensory neurons in a time- and dose-dependent manner. CML formation was prevented by addition of aminoguanidine, an inhibitor of AGE formation. This culture system provides a useful model to analyze the role of the glycoxidation reaction in neuronal aging and neurodegenerative disorder.

Advanced glycation end products co-localized with astrocytes and microglial cells in Alzheimer's disease brain.

In the previous study [Takeda et al. (1996) Neurosci Lett 221: 17-21], we reported that the advanced glycation end products (AGEs) in the external space of neuronal perikarya (extraneuroperikaryal AGE deposits) were significantly abundant in the Alzheimer's brain. In this study, we investigated the spatial relationship of the extraneuroperikaryal AGE (carboxymethyllysine and pentosidine) deposits in astrocytes and microglial cells in the Alzheimer's disease brain using double immunolabelling for AGEs and astrocyte or microglial cell markers. Most of the extraneuroperikaryal AGE deposits were co-localized with glial fibrillary acidic protein-positive astrocytes. AGE deposit-bearing astrocytes also contained Gomori-positive granules. Furthermore, some of the extraneuroperikaryal AGE deposits were co-localized with microglial cells. These extraneuroperikaryal AGEs may activate astrocyte and microglia, and play a role in pathogenesis of Alzheimer's disease.

Presenilin-1 protein expression in familial and sporadic Alzheimer's disease.

Mutations of the presenilin PS1 and PS2 genes are closely linked to aggressive forms of early-onset (< 60 years) familial Alzheimer's disease. A highly specific monoclonal antibody was developed to identify and characterize the native PS1 protein. Western blot analyses revealed a predominant 32-kd immunoreactive polypeptide in a variety of samples, including PC12 cells transfected with human PS1 complementary DNA, brain biopsy specimens from demented patients, and postmortem samples of frontal neocortex from early-onset familial Alzheimer's disease cases (PS1 and PS2), late-onset sporadic Alzheimer's disease cases, and cases of other degenerative disorders. This truncated polypeptide contains the N-terminus of PS1 and appeared unchanged across cases. In 2 early-onset cases linked to missense mutations in the PS1 gene, a PS1 immunoreactive protein (approximately 49 kd) accumulated in the frontal cortex. This protein was similar in size to full-length PS1 protein present in transfected cells overexpressing PS1 complementary DNA, and in lymphocytes from an affected individual with a deletion of exon 9 of the PS1 gene, suggesting that mutations of the PS1 gene peturb the endoproteolytic processing of the protein. Immunohistochemical studies of control brains revealed that PS1 is expressed primarily in neurons, with the protein localized in the soma and dendritic processes. In contrast, PS1 showed striking localization to the neuropathology in early-onset familial Alzheimer's disease and sporadic Alzheimers' disease cases. PS1 immunoreactivity was present in the neuritic component of senile plaques as well as in neurofibrillary tangles. Localization of PS1 immunoreactivity in familial and sporadic Alzheimer's disease suggests that genetically heterogeneous forms of the disease share a common pathophysiology involving PS1 protein.

Elevated cerebrospinal fluid levels of manganese superoxide dismutase in bacterial meningitis.

We examined the mechanism of increase of manganese superoxide dismutase (Mn SOD) in the cerebrospinal fluid (CSF) in bacterial meningitis (BM). The elevated levels of Mn SOD in the CSF in BM, measured with an enzyme immunoassay method, were more prominent than those in aseptic meningitis (AM) and encephalitis (EN). In AM and EN Mn SOD levels well correlated with levels of neuron-specific enolase and S-100b protein, which are markers of damages to nervous tissues, but did not with any of them in BM. CSF concentrations of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha) were higher in BM than in AM and EN. From the serial measurements in BM, the peak values of these cytokines chronologically preceded or corresponded to those of Mn SOD. Immunohistochemically, a large number of the glial cells were stained for Mn SOD in the cerebral cortex from a patient with BM. By contrast, in the normal cerebral cortex, the glial cells were negative for Mn SOD staining. These results suggest that the marked increase of Mn SOD in the CSF in BM may be related to the increase of such cytokines as TNF-alpha and IL-1 alpha and that these cytokines may play a role in the induction of Mn SOD in nervous tissues.

Somatic diversification and selection of immunoglobulin heavy and light chain variable region genes in IgG+ CD5+ chronic lymphocytic leukemia B cells.

Chronic lymphocytic leukemia (CLL) is characterized by the clonal expansion of CD5-expressing B lymphocytes. Most studies have found that these leukemic CD5+ B cells, like their normal counterparts, use immunoglobulin (Ig) variable (V) region genes that exhibit minimal, if any, somatic diversity. These and other observations have suggested that CD5+ B cells may be incapable of generating Ig V gene diversity, and therefore may not be able to develop higher affinity binding sites that could be selected by antigen. However, most of the studies of CLL and normal CD5+ B cells have focused on IgM-producing cells. Since somatic mutations are most often seen in B cells that have undergone an isotype class switch, we analyzed the Ig heavy (H) and light (L) chain variable region genes of seven IgG+CD5+ CLL B cells to determine if somatic diversification and antigen selection had occurred. The data derived provide evidence for skewed use, somatic diversification, and antigenic selection of the Ig V region genes. Nonrandom use of both H and L chain V region genes was manifested by an overrepresentation of VH4 and VKI family genes and the underrepresentation of the JH4 gene segment. Furthermore, VH4 gene use was restricted to only two family members (4.21 and 4.18). In four of the seven cases, the VH and VL genes displayed > or = 5% difference from the most homologous known germline counterparts. Polymerase chain reaction and Southern blot analyses performed in two of these patients demonstrated that their unique VH CDR2 and adjacent sequences were not present in their germline DNA. In addition, a significant level of diversity was seen in the rearranged DJH segments and at the VL-JL junctions of every patient that occurred both at the time of recombination and subsequently. The localization of replacement changes to complementarity determining regions of some patients suggested that antigen selection had occurred. Furthermore, the mutations identified in the VH and VL genes of each individual patient were strikingly similar, both in number and location. Collectively, the data indicate that a subset of CD5+ CLL B cells can display Ig V region gene mutations. In addition, they are consistent with the notions that in some cases antigen selection of these mutations may have occurred, and that antigen stimulation may be a promoting factor in the evolution of certain CLL clones.

A study of parkinsonism in multiple system atrophy: clinical and MRI correlation.

We investigated clinical and MRI correlation in 18 patients with clinically-diagnosed multiple system atrophy (MSA) and 16 age-matched controls, using 1.5 T magnetic resonance imaging (MRI). We evaluated the severity of parkinsonism in each MSA patient. In assessing the MRI findings, we examined three parameters quantitatively: width of the pars compacta of the substantia nigra (SNc); putaminal hypointensity on T2-weighted images; and putaminal atrophy. As in previous studies, SNc width was narrowed and the putaminal signal intensity was decreased in patients with MSA compared with controls. The clinical severity of parkinsonism did not correlate significantly with the SNc width or the score of putaminal hypointensity in MSA. However, not only did putaminal atrophy occur, but correlated well with the severity of parkinsonism in MSA. A significant correlation could not be established between narrowing of SNc and shrinkage of the putamen. These findings suggest that putaminal atrophy is associated with the clinical manifestations of parkinsonism and do not support the hypothesis that transsynaptic degeneration occurs in MSA.

Unusual findings on PET study of a patient with posterior cortical atrophy.

We present a patient with posterior cortical atrophy in whom positron emission tomography (PET) showed unusual findings. This 65-year-old man had a 5-year history of slowly progressive apperceptive visual agnosia and Balint syndrome, but with a relatively well-preserved intelligence and language ability even in the later stages of illness. No relevant features in this patient or his family were identified. Laboratory and radiographic investigations indicated that cerebral damage was due to primary degeneration. His symptoms resembled those of patients with posterior cortical atrophy. A PET study revealed that cerebral metabolism was reduced in the dorsal regions of the entire cortex and asymmetrical with the main site of damage on the right. The severity in asymmetry increased dorsally. These 2 types of predilection for dorsal regions had not previously been reported in such patients. These unusual PET findings may indicate the presence of pathological changes not yet identified.

An immunohistochemical study of the neuronal expression of manganese superoxide dismutase in sporadic amyotrophic lateral sclerosis.

Neuronal expression of manganese superoxide dismutase (MnSOD) in sporadic amyotrophic lateral sclerosis (sALS) was investigated by an immunohistochemical method. The brains and spinal cords from 11 patients with sALS and 20 normal controls (NCs) were used, and the following four nuclei (three motor nuclei and one autonomic nucleus) were examined: the oculomotor nucleus; the hypoglossal nucleus; the cervical motor nucleus; and Onuf's nucleus. Serial sections were stained by the Klüver-Barrera (KB) method and with human-MnSOD-specific antibodies. We counted the total number of neurons visible after KB staining and the total number of positive neurons after immunostaining. The average total number of neurons after KB staining was similar in sALS patients and NCs in both the oculomotor nucleus and Onuf's nucleus, but the number in the hypoglossal and cervical motor nuclei was significantly lower in sALS. The ratio of MnSOD-positive neurons to total neurons visible after KB staining, calculated as an index of the expression of MnSOD, was significantly higher in the oculomotor nucleus and Onuf's nucleus, and lower in the hypoglossal nucleus in sALS patients than in NCs. In the cervical motor nucleus, the ratio in sALS patients did not differ from that in NCs. These results suggest that production of toxic superoxide radicals might be increased in sALS, and that neurons that successfully induce the expression of sufficient MnSOD can survive the disease process, while those failing to activate adequate expression of the enzyme succumb to the toxic effects of the radicals and die.

IgG+, CD5+ human chronic lymphocytic leukemia B cells. Production of IgG antibodies that exhibit diminished autoreactivity and IgG subclass skewing.

Several questions exist regarding CD5+ B cells. These include the ability of these cells, as compared to CD5- B cells, to undergo an Ig isotype class switch, the subclasses utilized, and the effects that switching may have on antigen binding. To address these issues, ten patients with chronic lymphocytic leukemia (CLL) whose CD5+ leukemic B cell clones produced IgG were studied. Monoclonal IgG was collected from PMA-stimulated CLL cells and from heterohybridomas constructed with these cells, and then analyzed for IgG subclass utilization, autoreactivity, and DNA idiotype expression. The monoclonal B cells from 80% of the CLL patients produced IgG1 and those from 20% produced IgG3. None produced IgG2. In contrast to the known autoreactivity of IgM-producing CD5+ CLL cells (> 50% autoreactive), none of these IgG antibodies reacted significantly with the autoantigens tested. However, three did react significantly with autoantigen after artificially increasing antibody valency by crosslinking. Whereas five of the IgG molecules expressed a cross reactive idiotypic (CRI) marker characteristic of non-mutated kappa anti-DNA antibodies, three expressed a CRI displayed primarily on mutated IgG anti-DNA antibodies. Thus, some CD5+ human B cells can undergo an isotype class switch that for these CLL cells is biased against IgG2 and in favor of the IgG1 and IgG3. In their native state the IgG molecules secreted by these isotype-switched CD5+ cells have diminished autoreactivity, as compared to IgM-producing CLL cells. Since some of the IgG antibodies could be made auto- and poly-reactive by increasing antigen-binding valency, while others expressed idiotypic markers of mutated antibodies, certain of these CD5+ B cells probably utilize non-mutated Ig V genes coding for polyreactive antibodies, whereas others may use genes that have undergone somatic mutation and that code for more restricted specificities. Therefore, both valency and VH gene mutation may account for the diminished autoreactivity of these CD5+ B cell-derived IgG antibodies.

A histometrical study on the globus pallidus in Huntington's disease.

Pathological change of the globus pallidus (GP) in 6 cases of Huntington's disease (HD) was examined histometrically by comparison with 10 normal control cases. All but 1 case of HD were in late stages of the disease. Total neuronal count, area of GP, and neuronal cell density were measured in 5 selected regions of coronal sections taken along the antero-posterior axis. Contrary to the findings of previous reports, no neuronal depletion was recognized in HD in any region despite marked atrophy of tissue bulk. The atrophy was more severe in the external segment (GPe) than in the internal segment (GPi). Reactive astrocytosis and fibrillary gliosis were observed in the atrophic lesions. These results indicate that atrophy of the GP can be attributed to striato-pallidal fiber loss and not to neuronal depletion even in the late stages. These findings support the hypothesis that loss of striato-GPe fibers plays the most important role in choreic movements in HD. It remains to be determined whether the pallidal neurons are also preserved in the end stage of the disease.

Anti-CD23 monoclonal antibodies: comparisons of epitope specificities and modulating capacities for IgE binding and production.

A large battery of anti-CD23 mAb were compared for their epitope specificities and for their abilities to alter both IgE binding to cell-associated CD23 and IgE production in vitro in response to three sets of stimulants. The nine mAb tested can be divided into four families which define four antigenic epitopes (A-D) of CD23. Of these four families, two bind antigenic sites, (A and D) that appear to lie outside the IgE ligand binding site and two bind sites (B and C) that appear to be located within or close to this site, as determined by the abilities of appropriate mAb to alter IgE binding to CD23. The effects that these mAb had on IgE secretion by normal peripheral blood mononuclear cells (PBMNC) varied depending on the stimulant employed to induce IgE production. Interactions with epitope A, which was found to lie outside the ligand binding site and to be made more accessible by binding of mAb to other epitopes, had different effects on IgE production than interactions with the other epitopes. Indeed, mAb binding to this epitope lead to as much as a 10 fold enhancement in IgE biosynthesis induced by IL-4 alone or by IL-4 + hydrocortisone whereas interactions at the other sites resulted in almost complete inhibition of IgE production. In addition, mAb reactive with epitopes B and C had minimal effects on IgE production induced by IL-4 + anti-CD40 mAb whereas interactions at epitope A consistently enhanced IgE production. Finally, no apparent direct correlation was found between the ability of individual anti-CD23 mAb to alter IgE binding to cell-associated CD23 and their ability to modulate IgE production by PBMNC. These studies suggest that IgE binding to cell-associated CD23 does not have a major role in the de novo synthesis of IgE that involves CD23 interactions. In addition, the different effects that binding to epitope A vs B or C have on IgE synthesis suggest that molecular interactions between distinct portions of the CD23 molecule and other cell surface molecules expressed on the same B cell or adjacent communicating cells may lead to divergent cellular effects on IgE production. Finally these studies imply that only epitope A is involved in the generation of an IgE response through the CD40 pathway.

Monoclonal IgM, IgG, and IgA human rheumatoid factors produced by synovial tissue-derived, EBV-transformed B cell lines.

In an effort to study disease-related autoantibodies in rheumatoid arthritis (RA), rheumatoid factor (RF)-producing B cell lines were developed from the heterogeneous B cell populations infiltrating the synovial tissue of patients with arthritis. Over 125 EBV-transformed B cell cultures were derived from three patients: one with early pre-erosive RA, one with advanced RA, and one with osteoarthritis (OA). IgM, IgG, and IgA RF-producing B cell lines were found in all three series but with several significant differences. In each of the two RA patients, 22% of the Ig-producing cell lines secreted RF compared to 7% in the OA patient. The isotypes of these RF were mostly IgM in the early RA (62%) and the OA patient (60%) as contrasted to predominantly IgA (75%) and, to a lesser extent, IgG (12.5%) in the advanced RA patient. Analyses of the light (L) chain composition of these RF revealed that 82% of the IgM RF used kappa L chains whereas only 31% of the non-IgM RF used kappa chains. Antigen-binding analyses of these RF revealed that all the synovial tissue-derived RF from the advanced RA patient exhibited antigen binding specificities restricted to a narrow range of gamma globulins. In contrast, the synovial RF of the other two patients were either reactive with a broader spectrum of gamma globulins or reactive with a variety of unrelated antigens. In every instance, the gamma globulin-specific RF were of all three major isotypes whereas the polyreactive RF were restricted to the IgM isotype. These data demonstrate that synovial B cells from both RA and OA patients can produce RF and that significant differences can exist among patients in the percentage of RF generated and their H and L chain isotype distribution. The reversal of the kappa:lambda ratio among the IgG and IgA RF and the more restricted antigen-binding specificities of the IgG and IgA vs IgM RF suggest that a non-stochastic, possibly antigen-driven selection process was involved in their generation. The relevance of these differences in RF precursor frequency, H and L chain distribution, and antigen specificity to these two diseases warrants further investigation.

Production of autoantibodies by CD5-expressing B lymphocytes from patients with chronic lymphocytic leukemia.

CD5-expressing B lymphocytes from patients with selected chronic lymphoproliferative disorders were used to determine whether monoclonal populations of CD5+ human B cells produce autoantibodies. CD5+ B cells from 19 patients with chronic lymphocytic leukemia (CLL) and one with diffuse well-differentiated lymphocytic lymphoma (DWDL) were cultured, with and without mitogenic stimulation, to obtain Ig from these cells. 17 of the 20 samples produced Ig in vitro. mAb from nine of the 17 patients were reactive with either IgG, ssDNA, or dsDNA. In every instance, the autoantibodies displayed monotypic L chain usage that correlated precisely with the L chain expressed on the CD5+ leukemic B cell surface. These monoclonal autoantibodies varied in their degree of antigenic specificity; some were quite specific, reacting with only one antigen, whereas others were polyspecific, reacting with two or all three autoantigens tested. Three features distinguish these autoantibodies from those observed in prior studies of CD5+ B cells. First, they are clearly the products of monoclonal populations of CD5+ cells; second, several react with dsDNA, a specificity not previously reported and often seen in association with significant autoimmune disorders; and third, two of the monoclonal autoantibodies secreted by the CD5+ clones were of the IgG class. Although not all of the Ig-producing, CD5-expressing clones elaborated mAbs reactive with the autoantigens tested, greater than 50% did. It is possible that with a broader autoantigenic panel or with larger quantities of CLL/DWDL-derived Ig, even more autoantibody-producing clones might be identified. These studies may have important implications for the antigenic specificity of subsets of human B lymphocytes as well as for lymphoproliferative and autoimmune disorders in general.