Absence of spontaneous central nervous system remyelination in class II-deficient mice infected with Theiler's virus.

We previously showed that Theiler's murine encephalomyelitis virus (TMEV)-infected major histocompatibility complex (MHC) class II-deficient mice develop both demyelination and neurologic deficits, whereas MHC class I-deficient mice develop demyelination but no neurologic deficits. The absence of neurologic deficits in the class I-deficient mice was associated with preserved sodium channel densities in demyelinated lesions, a relative preservation of axons, and extensive spontaneous remyelination. In this study, we investigated whether TMEV-infected class II-deficient mice, which have an identical genetic background (C57BL/6 x 129) as the class I-deficient mice, have preserved axons and spontaneous myelin repair following chronic TMEV-infection. Both class I- and class II-deficient mice showed similar extents of demyelination of the spinal cord white matter 4 months after TMEV infection. However, the class I-deficient mice demonstrated remyelination by oligodendrocytes, whereas class II-deficient mice showed minimal if any myelin repair. Demyelinated lesions, characterized by inflammatory infiltrates in both mutants, revealed disruption of axons in class II- but not class I-deficient mice. Further characterization revealed that even though class II-deficient mice lacked TMEV-specific IgG, they had virus-specific IgM, which, however, did not neutralize TMEV in vitro. In addition, class II-deficient mice developed TMEV-specific cytotoxic T-lymphocytes in the CNS during the acute (7 days) disease, but these cytotoxic lymphocytes were not present in the chronic stage of disease, despite a high titer of infectious virus throughout the disease. We envision that the presence of demyelination, high virus titer, absence of remyelination, and axonal disruption in chronically infected class II-deficient mice contributes to the development of paralytic disease.

CNS cell populations are protected from virus-induced pathology by distinct arms of the immune system.

The basis for the distinct patterns of brain pathology in individuals experiencing virus-induced encephalitis may be related to either the tropism of the virus or the host's response to virus infection of the central nervous system (CNS). In these studies we used Theiler's murine encephalomyelitis virus (TMEV) and a series of mice deficient in various immune system components (alpha/beta T cells, antibody, Class I MHC, and Class II MHC) to examine the hypothesis that discrete populations of CNS cells are protected differentially from virus infection by distinct arms of the immune response. Here we demonstrate that the Class I-mediated immune response provided more protection from areas of the brain (brainstem, corpus callosum and cerebellum) with abundant white matter as there was significantly more disease in these areas in beta2m -/- (Class I-deficient) mice as compared to A beta(0) (Class II-deficient) mice. In contrast, the striatum, with an abundance of neurons, was protected from virus-induced pathology primarily by antibody. In addition, we determined that antibody and alpha/beta T cells provided protection from severe deficits and death during the acute phase of the disease. The data presented here support the hypothesis that distinct immune system components function to protect discrete areas of the CNS from virus-induced pathology.

Synthesis and biological evaluation of substituted flavones as gastroprotective agents.

Flavone (1) was found to protect against ethanol-induced gastric damage in rats; however, it is known that certain compounds in the flavone class, including flavone itself, are inducers of hepatic drug metabolizing enzymes. With the hope of identifying gastroprotective flavones that have minimal effects on drug metabolizing enzymes, we have synthesized and evaluated selected flavone analogs. Gastroprotective potency in the ethanol model was retained by methoxy substitution in the 5-position (4) and by methoxy (12) or methyl (14) substitution in the 7-position. A number of substituted analogs of the potent molecule 5-methoxyflavone (4) were also synthesized, and in many cases, these substitutions provided gastroprotective molecules. In order to assess liver enzyme induction potential, two of the gastroprotective flavones, 7-methoxyflavone (12) and 5-methoxy-4'-fluoroflavone (26), were examined for their effect on liver microsomal cytochrome P450 and 7-ethoxyresorufin O-dealkylase (CYP1A) activity. These two compounds caused minimal changes in the cytochrome P450 concentration and were considerably less potent than beta-naphthoflavone as inducers of CYP1A enzyme activity. Furthermore, following oral administration to rats, 5-methoxy-4'-fluoroflavone (26) was found to protect against indomethacin-induced gastric damage. These results indicate that, through appropriate substitution, flavones can be obtained that are gastroprotective but have minimal effects on drug-metabolizing enzymes.

Chronic exposure of neural cells to elevated intracellular sodium decreases mitochondrial mRNA expression.

Regulation of expression of mitochondrial DNA- (mtDNA-) encoded genes of oxidative phosphorylation can occur rapidly in neural cells subjected to a variety of physiological and pathological conditions. However, the intracellular signal(s) involved in regulating these processes remain unknown. Using mtDNA-encoded cytochrome oxidase subunit III (COX III), we show that its mRNA expression in a differentiated rat pheochromocytoma cell line PC12S is decreased by chronic exposure to agents that increase intracellular sodium. Treatment of differentiated PC12S cells either with ouabain, an inhibitor of Na/K-ATPase, or with monensin, a sodium ionophore, decreased the steady-state levels of COX III mRNA by 50%, 3-4 h after addition of the drugs. No significant reduction in mtDNA-encoded 12S rRNA or nuclear DNA-encoded beta-actin mRNA were observed. Removal of the drugs restored the normal levels of COX III mRNA. Determination of half-lives of COX III mRNA, 12S rRNA, and beta-actin mRNA revealed a selective decrease in the half-life of COX III mRNA from 3.3 h in control cells to 1.6 h in ouabain-treated cells, and to 1 h in monensin-treated cells. These results suggest the existence of a mechanism of posttranscriptional regulation of mitochondrial gene expression that is independent of the energetic status of the cell and may operate under pathological conditions.

Validity studies of the filial anxiety scale.

Factor analytic and construct validity studies were conducted to explore the validity of Cicirelli's (1988) 13-item Filial Anxiety Scale (FAS). The State-Trait Anxiety Inventory (Spielberger, 1983), and the Marlowe-Crowne Social Desirability Scale (Crowne & Marlowe, 1960), were a part of the investigation. The results offer support for the validity of the FAS subscales and the FAS' usefulness as an instrument for measuring adult children's feelings concerning elder-parent care.

Assessing filial maturity through the use of the Filial Anxiety Scale.

This study was an investigation of a late-in-life stage of development known as filial maturity (Blenkner, 1965). The Filial Anxiety Scale (Cicirelli, 1988) was used in a cross-sectional design to assess whether the filial anxiety of adult caregivers of aging parents varied in a manner consistent with Blenkner's concept. Results clearly supported Blenkner's position that there is a late-in-life period of development during which some individuals experience heightened levels of filial anxiety, or a filial crisis, prompted by the caregiving demands of an aging parent. This crisis is then followed by a significant decrease in anxiety and results in the attainment of a developmental period characterized by filial maturity.

Relationship between gastric inflammatory response and symptoms in patients infected with Helicobacter pylori.

The relationship between the histologic severity of gastritis and associated symptoms was examined in 19 adult patients infected with Helicobacter pylori. At the time of gastrointestinal endoscopy, symptoms of dyspepsia were assessed by means of a linear analog scale. Gastric inflammation was quantitated with histomorphometric techniques. Symptoms such as epigastric pain, burping/belching, and nausea correlated with the degree of inflammation. These positive correlations suggest that the severity of the histologic gastritis contributes to the severity of symptoms. Therefore, utilization of a linear analog scale to assess symptoms may be a useful technique in evaluating the outcome of therapeutic trials of patients with symptomatic H. pylori infection.

Gastritis associated with infection by Helicobacter pylori in humans: geographical differences.

Previous studies have indicated that infection rates of Helicobacter pylori are influenced by geographical factors. The present studies evaluate the characteristics of gastritis, associated with infection by H. pyrlori, and demonstrate relationships between different geographical locations and the extent of inflammatory cell accumulation in the gastric mucosa. Gastric biopsy specimens were obtained from patients infected with H. pylori at three clinical sites (two from North America and one from South America). Gastric inflammation was evaluated by quantitative histomorphometric techniques. Patients from South America had a more severe gastritis than did those from North America. Additionally, in South American patients the neutrophil was the predominant inflammatory cell type in the gastric mucosa. In contrast, the lymphocyte was the primary cell composing the mucosal infiltrate of infected North American subjects. Eosinophil infiltration into the mucosa correlated with the extent of mucosal atrophy; however, there were no differences between the North and South American patient populations in the extent of mucosal atrophy present in the specimens. We conclude that the characteristics (severity and cell type) of gastritis associated with infection by H. pylori are influenced by geographical factors that may be similar to those that modify infection rates for different geographical locations.

Differential effect of interferon-gamma and interleukin-2 on the induction of IgA and IgM anti-dextran responses.

Supernatants from T-cell lines and T-cell hybridomas can substitute for T cells in the induction of the anti-alpha(1,3) Dextran B1355 plaque-forming cell response in culture. The present study sought to define the lymphokines required for the induction of IgA and IgM anti-alpha (1,3) dextran responses. Recombinant Interferon-gamma (IFN-gamma) supported the induction of low levels of IgA anti-alpha(1,3) dextran plaque-forming cells in splenic B-cell cultures. IgA responses were substantially increased when cultures containing IFN-gamma were supplemented with an interleukin 2 (IL-2)-containing supernatant from the murine T-cell hybridoma BW.Mls, purified murine IL-2, or recombinant human IL-2. In striking contrast, IgM anti-alpha(1,3) dextran plaque-forming cells were not produced in cultures containing IFN-gamma alone or in combination with purified or recombinant IL-2. However, substantial IgM responses could be produced in cultures containing IFN-gamma and BW.Mls supernatant. This data indicates that there may be different lymphokine requirements for the induction of IgA and IgM anti-alpha(1,3) dextran B cells, or alternatively, such B cells may be in different stages of differentiation and therefore, not respond to the same lymphokines.

Diagnosis and management of congenital hypothyroidism.

Thyroid hormones are integral to the development and maturation of the central nervous system as well as normal growth and development. Comprehensive knowledge of the maturation and function of the thyroid gland is essential to understanding the pathophysiology of thyroid dysfunction. Early diagnosis and appropriate treatment in thyroid disease are imperative for normalization of thyroid hormone ratios. Optimal management includes early introduction and strict adherence to a regimen of L-thyroxine and routine monitoring of thyroid levels throughout life. Parents need to understand the importance of consistent medication administration and daily assessment of well-being because these actions are crucial to the attainment of an optimal level of development for infants with congenital hypothyroidism.

Regulation of the anti-alpha (1,3) dextran response: two populations of dextran-reactive B cells that differ in their T cell requirements for induction to antibody synthesis.

The in vitro antibody response to dextran B1355S, a thymus-independent Type 2 antigen, requires T cell-derived lymphokines but is not thought to require an activation signal from an antigen-specific T helper cell. The present study demonstrates that there are two dextran-reactive B cell populations in BALB/c mice with respect to the T cell requirements for the generation of antibody-forming cells. One population found among dextran-reactive spleen B cells from 12- to 14-mo-old BALB/c mice generated anti-dextran PFC in the presence of B cell growth factor (BCGF II) and IL 2 or the combination of BCGF II, IL 2, and IFN-gamma. A second population of dextran-reactive B cells found in spleen and Peyer's patches of 2-mo-old unprimed mice did not respond to these same lymphokines, but did generate anti-dextran plaque-forming cells in the presence of Thy-1.2+, L3T4+ T cells from Peyer's patches. However, splenic B cells obtained from 2-mo-old mice that had been primed with dextran 2 to 3 days after birth were shown to be responsive to the same lymphokines as dextran-reactive B cells from 12- to 14-mo-old mice. These results suggest that previous priming with dextran B1355S induces a dextran-specific B cell population that can be activated to antibody-forming cells in the presence of antigen and T cell-derived lymphokines, whereas a second, unprimed population requires an additional activation signal from L3T4+ T cells.

Hymenolepis microstoma: mouse strain differences in resistance to a challenge infection.

Antibody responses and host resistance to the tapeworm, Hymenolepis microstoma, were investigated using AKR/J and C3HeB/FeJ strains of mice. AKR mice were significantly more resistant than controls to a secondary infection following exposure to a 3-, 21-, or 40-day primary infection. During a primary infection, intestinal anti-worm antibody responses measured by an enzyme-linked immunosorbent assay were elevated in the more resistant AKR strain, whereas serum antibody titers did not differ between the two strains. However, during a secondary infection, serum IgA titers were higher in AKR mice than C3H mice. Suppression of the serum IgA anti-worm response by oral administration of lipopolysaccharide also suppressed resistance to a secondary infection. Intraperitoneal immunization with worm antigen resulted in a minor degree of protection in AKR mice. This protection was associated with increased intestinal antibody titers compared to mice not demonstrating protection. These results suggest that the protective responses observed in AKR mice relative to C3H mice reflect differences in mucosal antibody responses to H.

Regulation of the IgM and IgA anti-dextran B1355S response: synergy between IFN-gamma, BCGF II, and IL 2.

T cell help is required for the induction of the humoral antibody response to dextran B1355S, a type II thymus-independent bacterial polysaccharide antigen. In the present study we have identified three B cell growth and differentiation factors that can substitute for T cells in the induction of IgM and IgA antibody responses to alpha(1,3) glucan determinants on dextran B1355S. Dextran B1355S stimulated murine B cell cultures supplemented with a combination of murine recombinant interferon-gamma (IFN-gamma) and a late-acting B cell growth and differentiation factor, BCGF II, produced both IgA and IgM anti-alpha(1,3) dextran plaque-forming cells (PFC). Interleukin 2 (IL 2) was not required for those responses. In contrast, recombinant IFN-gamma and recombinant IL 2 in combination supported the induction of IgA but not IgM anti-alpha(1,3) dextran PFC. In all cases, depletion of surface IgA-bearing B cells significantly decreased IgA but not IgM anti-dextran responses, indicating that the B cells responding to those lymphokines already were committed to IgA expression. These studies indicate that B cell growth and differentiation factors can exhibit differential effects on the induction of IgA compared with IgM responses.

Vasoative intestinal peptide and the watery diarrhea syndrome.

A sensitive and specific radioimmunoassay for the detection of vasoactive intestinal peptide has been used to study patients with the watery diarrhea syndrome. In eleven patients the syndrome was associated with tumors, and plasma levels of vasoactive intestinal peptide were elevated. VIP levels returned towards normal in five treated patients coincident with amelioration of symptoms. Normal values were obtained in patinets with chronic pancreatitis, sprue, medullary carcinoma, Zollinger-Ellison Syndrome and laxative abuse. In six other patients with indistinguishable syndrome and no findings of tumor at laparotomy and autopsy, vasoactive intestinal peptide levels were normal. The results suggest that VIP may be the causative agent in patients with the watery diarrhea syndrome and tumors, but that an indistinguishable syndrome exists for which VIP is not the cause.

Pharmacology of angioplasty and intravascular thrombolysis.

Interventional angiographic techniques are of increasing importance in the management of arteriosclerosis and its complications. Two areas of particular interest are the treatment of focal arterial stenoses by percutaneous transluminal angioplasty and the treatment of arterial thromboemboli with selective infusion of thrombolytic agents. The administration of multiple drugs, in various combinations, is a critical factor in the success of these interventions. To effectively use this new pharmacoangiography, it is important to understand both the pathophysiology of the atherosclerotic or thrombotic process being treated and the actions of the drugs used. Preserving the effect of angioplasty relies on preventing thrombus formation and preventing recurrence of the atherosclerotic obstruction. Heparin during the procedure is clearly useful for the former, and aspirin in small doses and other antiplatelet medications are indicated for the latter. The precise utility of long-term anticoagulation, of low molecular weight dextran, and of various antiplatelet regimens remains to be proven. The theoretical importance of these medications in improving long-term patency rests on the effects they have on platelet and vessel wall prostaglandins, on intimal smooth muscle cell proliferation, and on the thrombogenicity of injured arterial intima. Fibrinolytic therapy, with streptokinase and urokinase, has been used for many years. Selective intraarterial use, however, is a new and promising application. Intracoronary streptokinase infusion during acute myocardial ischemia appears to prevent or limit infarction in certain patients. Peripheral use for acute arterial occlusion, either in native vessels or in grafts, is an area of great promise. Key considerations are thrombus age, size, and location, and the status of the arterial flow proximal and distal to the obstruction.

Quantitation of spinal cord demyelination, remyelination, atrophy, and axonal loss in a model of progressive neurologic injury.

Spinal cord pathology, such as demyelination and axonal loss, is a common feature in multiple models of central nervous system (CNS) injury and disease. Development of methods to quantify spinal cord pathology objectively would aid studies designed to establish mechanisms of damage, correlate pathology with neurologic function, and assess therapeutic interventions. In this study, we describe sensitive methods to objectively quantify spinal cord demyelination, remyelination, atrophy, and axonal loss following the initiation of a progressive inflammatory demyelinating disease with Theiler's murine encephalomyelitis virus (TMEV). Spinal cord demyelination, remyelination, and atrophy were quantified from representative 1-microm-thick cross sections embedded in Araldite plastic using interactive image analysis. In addition, this study demonstrates novel, automated methodology to quantify axonal loss from areas of normal-appearing white matter, as a measure of secondary axonal injury following demyelination. These morphologic methods, which are applicable to various models of CNS injury, provide an innovative way to assess the benefits of therapeutic agents, to determine mechanisms of spinal cord damage, or to establish a correlation with sensitive measures of neurologic function. J. Neurosci Res 58:492-504.

Digital subtraction angiography: overview of technical principles.

The rapid development of equipment for digital subtraction angiography (DSA) has created a new diagnostic imaging method, the limits of which have not been scientifically determined. Yet through aggressive marketing, the technique is already beginning to permeate radiologic practice. The radiologist requires technical understanding of the instrumentation for informed judgment on clinical applications. DSA depends on the mating of high-resolution image-intensifier and television technology with computerized information manipulation and storage. In this overview, the individual components of the system are analyzed, from the generator to the image intensifier to the television system to the associated computer. By examining the role of each component, the current limitations and the areas of possible future development of DSA can be understood. This provides a basis for dealing with current technology and for evaluating the rapid technological changes that will occur over the next few years.

Interleukin 5 and interleukin 4 produced by Peyer's patch T cells selectively enhance immunoglobulin A expression.

Considerable evidence suggests that the high frequency of B cells committed to the IgA isotype in Peyer's patches is regulated by T lymphocytes. To understand more accurately the mechanism of this immunoregulation, an autoreactive T cell line from Peyer's patches was generated by culturing L3T4+ Peyer's patches T cells with syngeneic B cell blasts. The resulting T cell line, designated PT-1, and a clone derived from this line, PT-1.14, stimulated immunoglobulin secretion in spleen B cells with a preferential enhancement of IgA and IgG1 isotypes. Supernatant derived from concanavalin A-stimulated PT-1 or PT-1.14 cells could also enhance IgA secretion if spleen B cells were preactivated with lipopolysaccharide. Peyer's patches T cell supernatant did not contain IgA-specific binding factors. PT-1 supernatant scored positive in lymphokine assays for interleukin (IL)-2, IL-4 (B cell stimulatory factor 1), IL-5 (B cell growth factor II), and interferon-gamma, whereas PT-1.14 supernatant was positive for IL-4 and IL-5 and negative for IL-2 and interferon-gamma. Only IL-5 enhanced IgA secretion in lipopolysaccharide-activated B cells and this response was increased two- to three-fold by IL-4. These results suggest that the type 2 T helper subset which produces both IL-5 and IL-4 plays a primary role in regulating IgA expression.