Coexisting lower urinary tract symptoms and erectile dysfunction: a systematic review of epidemiological data.

OBJECTIVE: Assess and categorise the available prevalence data on coexistent LUTS and ED in the general population and among individuals consulting a healthcare provider for any reason or when seeking treatment for LUTS and/or ED. METHODS: Literature search of English-language articles published during the last 15 years. RESULTS: Of 23 relevant studies identified, 12 used both the International Prostate Symptom Score (IPSS) and International Index of Erectile Function (IIEF) as assessment tools and 11 used alternative approaches. In studies using both IPSS and IIEF, overall prevalence of coexistent LUTS/ED of any severity was not assessable for men in the general population, but rates ranged from 14-37% based on alternative assessments. In the general male population, 13-29% had moderate to severe LUTS and 8-35% had moderate to severe ED. In studies using both IPSS and IIEF, overall prevalence of coexistent LUTS and ED of any severity was 71-80% among men seeking treatment for LUTS, and 74% based on alternative assessments. Among men who sought treatment for either condition, 67-100% had moderate to severe LUTS and 43-59% had moderate to severe ED. Coexistence of LUTS and ED increased with age, ranging from 59-86% among men aged 40s to 60s in primary care to 79-100% in treatment-seeking men with LUTS aged 50s to 70s. Impact on QoL varied, but health-related QoL was generally worse in treatment-seeking men compared with men in the general population. CONCLUSIONS: Although less than one-third of middle-aged and older men in the general population have coexisting LUTS and ED, most men seeking treatment for either LUTS or ED have both conditions. Symptom severity and impact on QoL in each condition increase when LUTS and ED coexist.

Identification of a progenitor of the CTX-M-9 group of extended-spectrum beta-lactamases from Kluyvera georgiana isolated in Guyana.

Chromosomal beta-lactamase genes (bla(KLUY)) from six Kluyvera georgiana strains isolated in Guyana were cloned and expressed in Escherichia coli. KLUY-1 exhibited 100% amino acid identity with the extended-spectrum beta-lactamase CTX-M-14. We also show that a 2.7-kb Kluyvera chromosomal region exhibits 99% nucleotide identity to a portion of In60 that includes bla(CTX-M-9).

Telomere shortening in T cells correlates with Alzheimer's disease status.

Telomeres, the repeated sequences that cap chromosome ends, undergo shortening with each cell division, and therefore serve as markers of a cell's replicative history. In vivo, clonal expansion of T cells during immune responses to both foreign and autoantigens is associated with telomere shortening. To investigate possible immune alterations in Alzheimer's disease (AD) that might impact current vaccine-based therapeutic strategies, we analyzed telomere lengths in immune cell populations from AD patients. Our data show a significant telomere shortening in PBMC from AD versus controls (P=0.04). Importantly, telomere length of T cells, but not of B cells or monocytes, correlated with AD disease status, measured by Mini Mental Status Exam (MMSE) scores (P=0.025). T cell telomere length also inversely correlated with serum levels of the proinflammatory cytokine TNFalpha (a clinical marker of disease status), with the proportion of CD8+ T cells lacking expression of the CD28 costimulatory molecule, and with apoptosis. These findings suggest an immune involvement in AD pathogenesis.

Oxygen-induced fetal pulmonary vasodilation is mediated by intracellular calcium activation of K(Ca) channels.

O(2) sensing in fetal pulmonary artery smooth muscle is critically important in the successful transition to air breathing at birth. However, the mechanism by which the fetal pulmonary vasculature senses and responds to an acute increase in O(2) tension is not known. Isolated fetal pulmonary artery smooth muscle cells were kept in primary culture for 5-14 days in a hypoxic environment (20-30 mmHg). These cells showed a 25.1 +/- 1.7% decrease in intracellular calcium in response to an acute increase in O(2) tension. Low concentrations of caffeine (0.5 mM) and diltiazem also decreased intracellular calcium. The decrease in intracellular calcium concentration in response to increasing O(2) was inhibited by iberiotoxin and ryanodine. Freshly isolated fetal pulmonary artery smooth muscle cells exhibited "spontaneous transient outward currents," indicative of intracellular calcium spark activation of calcium-sensitive potassium channels. The frequency of spontaneous transient outward currents increased when O(2) tension was increased to normoxic levels. Increasing fetal pulmonary O(2) tension in acutely instrumented fetal sheep increased fetal pulmonary blood flow. Ryanodine attenuated O(2)-induced pulmonary vasodilation. This study demonstrates that fetal pulmonary vascular smooth muscle cells are capable of responding to an acute increase in O(2) tension and that this O(2) response is mediated by intracellular calcium activation of calcium-sensitive potassium channels.

A beta-peptides enhance vasoconstriction in cerebral circulation.

Amyloid-beta (A beta)-peptides are involved in the pathophysiology of Alzheimer's dementia. We studied the effects of A beta on selected constrictor responses of cerebral circulation. Mice were anesthetized (by using urethane-chloralose) and equipped with a cranial window. Arterial pressure and blood gases were monitored and controlled. Cerebral blood flow (CBF) was monitored by a laser Doppler probe. Topical superfusion with A beta 1-40 (0.1-10 microM), but not with the reverse peptide A beta 40-1, reduced resting CBF (-29 +/- 4% at 5 microM; P < 0.05) and augmented the reduction in CBF produced by the thromboxane analog U-46619 (+45 +/- 3% at 5 microM; P < 0.05). A beta 1-40 or A beta 1-42 did not affect the reduction in CBF produced by hypocapnia. The reduction in resting CBF and the enhancement of vasoconstriction were reversed by treatment with the free radical scavengers superoxide dismutase or manganic(I-II)meso-tetrakis(4-benzoic acid)porphyrin. Substitution of the methionine residue in position 35 with norleucine, a mutation that abolishes the ability of A beta to produce free radicals, abolished its vascular effects. Nanomolar concentrations of A beta 1-40 constricted isolated pressurized middle cerebral artery segments with intrinsic tone (-16 +/- 3% at 100 nM; P < 0.05). We conclude that A beta acts directly on cerebral arteries to produce vasoconstriction and to enhance selected constrictor responses. The evidence supports the idea that A beta-induced production of reactive oxygen species plays a role in this effect. The vascular actions of A beta may contribute to the deleterious effects resulting from accumulation of this peptide in Alzheimer's dementia.

Effects of oxidant stress on inflammation and survival of iNOS knockout mice after marrow transplantation.

In a model of idiopathic pneumonia syndrome after bone marrow transplantation (BMT), injection of allogeneic T cells induces nitric oxide (.NO), and the addition of cyclophosphamide (Cy) generates superoxide (O.) and a tissue-damaging nitrating oxidant. We hypothesized that.NO and O. balance are major determinants of post-BMT survival and inflammation. Inducible nitric oxide synthase (iNOS) deletional mutant mice (-/-) given donor bone marrow and spleen T cells (BMS) exhibited improved survival compared with matched BMS controls. Bronchoalveolar lavage fluids obtained on day 7 post-BMT from iNOS(-/-) BMS mice contained less tumor necrosis factor-alpha and interferon-gamma, indicating that.NO stimulated the production of proinflammatory cytokines. However, despite suppressed inflammation and decreased nitrotyrosine staining, iNOS(-/-) mice given both donor T cells and Cy (BMS + Cy) died earlier than iNOS-sufficient BMS + Cy mice. Alveolar macrophages from iNOS(-/-) BMS + Cy mice did not produce.NO but persisted to generate strong oxidants as assessed by the oxidation of the intracellular fluorescent probe 2',7'-dichlorofluorescin. We concluded that.NO amplifies T cell-dependent inflammation and addition of Cy exacerbates.NO-dependent mortality. However, the lack of.NO during Cy-induced oxidant stress decreases survival of T cell-recipient mice, most likely by generation of.NO-independent toxic oxidants.

Polycyclic aromatic hydrocarbon diol epoxides increase cytosolic Ca(2+) of airway epithelial cells.

Polycyclic aromatic hydrocarbons (PAHs) increase cytosolic Ca(2+) concentration ([Ca(2+)](i)) in lymphocytes and mammary epithelial cells, but little is known regarding their effects on [Ca(2+)](i) in airway epithelium. We hypothesized that benzo[a]pyrene (BP) and/or anti-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE), a carcinogenic BP metabolite, increases [Ca(2+)](i) in untransformed human small airway epithelial (SAE) cells and that their effects on [Ca(2+)](i) are directly proportional to carcinogenicity. SAE [Ca(2+)](i) was determined by a ratiometric digital Ca(2+) imaging system. BPDE increased SAE [Ca(2+)](i) within 20 s in media with high (1 mM) and low (10 nM) Ca(2+) at a threshold concentration of 0.2 nM. Elevation of [Ca(2+)](i) persisted longer with high Ca(2+). Neither BP nor solvent altered [Ca(2+)](i). Thapsigargin and inositol 1,4,5- phosphate receptor (InsP(3)R) antagonists inhibited this BPDE action with low Ca(2+). We conclude that BPDE but not BP increases [Ca(2+)](i) partly by mobilizing Ca(2+) from cytosolic stores through an InsP(3)R. The most potent carcinogenic PAH diol epoxide increased in SAE [Ca(2+)](i) at the lowest threshold concentration, suggesting that carcinogenicity is directly proportional to the action of PAHs on SAE [Ca(2+)](i). Short-term exposure to BPDE 36 to 48 h before the study rendered SAE cells less sensitive to BPDE, suggesting that BPDE may also induce persistent changes in Ca(2+) signaling pathways.

Pulmonary vascular response to normoxia and K(Ca) channel activity is developmentally regulated.

To address developmental regulation of pulmonary vascular O(2) sensing, we tested the hypotheses that 1) fetal but not adult pulmonary artery smooth muscle cells (PASMCs) can directly sense an acute increase in O(2), 2) Ca2+-sensitive K(+) (K(Ca)) channel activity decreases with maturation, and 3) PASMC K(Ca) channel expression decreases with maturation. We used fluorescence microscopy to confirm that fetal but not adult PASMCs are able to sense an acute increase in O(2) tension. Acute normoxia induced a 22 +/- 2% decrease in cytosolic Ca2+ concentration ([Ca2+](i)) in fetal PASMCs and no change in ([Ca2+](i)) in adult PASMCs (P < 0.01). The effects of K(+) channel antagonists were studied on fetal and adult PASMC ([Ca2+](i)). Iberiotoxin (10(-9) M) caused PASMC ([Ca2+](i)) to increase by 694 +/- 22% in the fetus and caused no change in adult PASMCs. K(Ca) channel expression and mRNA levels in distal pulmonary arteries from fetal and adult sheep were examined. Both K(Ca) channel protein and mRNA expression in the distal pulmonary vasculature decreased with maturation. We conclude that maturation-dependent changes in PASMC O(2) sensing render the fetal PASMCs uniquely sensitive to an acute increase in O(2) tension at a biologically critical time point.

Immune effects of hormone replacement therapy in post-menopausal women.

Hormone replacement therapy (HRT) confers many health benefits to post-menopausal women. Despite links between estrogen and immune function prior to menopause, the immune status of women receiving HRT has not been rigorously investigated. This case-control study uses clinical laboratory assessment, flow cytometry, and functional assays to measure immune function. Participants included 27 post-menopausal women taking estrogen/progestin combinations, and 22 post-menopausal women not receiving HRT. Compared to the (-)HRT group, the (+)HRT group had more B-cells (p<0.05), higher mitogen-induced T-cell proliferation (p<0.05), and higher levels of induced TNF-alpha (p<0.05). There was a trend towards a lower proportion of CD4+ T-cells expressing the activation marker CD25+ (p<0.10). These findings represent a reversal of immune alterations associated with normal aging, suggesting that preservation or improvement of immune function may be associated with the use of HRT.

Fetal rabbit pulmonary artery smooth muscle cell response to ryanodine is developmentally regulated.

To study developmental changes in intracellular calcium handling in pulmonary artery smooth muscle cells (PASMCs), cells were isolated from distal and proximal pulmonary arteries from rabbits at different developmental stages: juvenile (4-6 wk old), newborn (<48 h), and full-term fetal. Isolated PASMCs were studied using the calcium-sensitive dye fura 2. Cells from each age group responded to caffeine with an increase in calcium; however, ryanodine (50 microM) only increased calcium in fetal distal PASMCs. The ryanodine-induced increase was due to influx of extracellular calcium because it was blocked by removal of extracellular calcium or by diltiazem. The calcium-sensitive potassium (K(Ca)) channel blocker iberiotoxin produced a transient increase in calcium in the fetal distal PASMCs, which could be inhibited by prior application of ryanodine. Conversely, the ryanodine response was inhibited if iberiotoxin was given first. With the use of electrophysiology and confocal microscopy, fetal PASMCs were shown to exhibit spontaneous transient outward currents and calcium sparks, respectively. These observations suggest that ryanodine-sensitive release of calcium from the sarcoplasmic reticulum and K(Ca) channels act together to control intracellular calcium only in fetal distal PASMCs.

Voltage-gated K(+)-channel activity in ovine pulmonary vasculature is developmentally regulated.

To examine mechanisms underlying developmental changes in pulmonary vascular tone, we tested the hypotheses that 1) maturation-related changes in the ability of the pulmonary vasculature to respond to hypoxia are intrinsic to the pulmonary artery (PA) smooth muscle cells (SMCs); 2) voltage-gated K(+) (K(v))-channel activity increases with maturation; and 3) O(2)-sensitive Kv2.1 channel expression and message increase with maturation. To confirm that maturational differences are intrinsic to PASMCs, we used fluorescence microscopy to study the effect of acute hypoxia on cytosolic Ca(2+) concentration ([Ca(2+)](i)) in SMCs isolated from adult and fetal PAs. Although PASMCs from both fetal and adult circulations were able to sense an acute decrease in O(2) tension, acute hypoxia induced a more rapid and greater change in [Ca(2+)](i) in magnitude in PASMCs from adult compared with fetal PAs. To determine developmental changes in K(v)-channel activity, the effects of the K(+)-channel antagonist 4-aminopyridine (4-AP) were studied on fetal and adult PASMC [Ca(2+)](i). 4-AP (1 mM) caused PASMC [Ca(2+)](i) to increase by 94 +/- 22% in the fetus and 303 +/- 46% in the adult. K(v)-channel expression and mRNA levels in distal pulmonary arteries from fetal, neonatal, and adult sheep were determined through the use of immunoblotting and semiquantitative RT-PCR. Both Kv2.1-channel protein and mRNA expression in distal pulmonary vasculature increased with maturation. We conclude that there are maturation-dependent changes in PASMC O(2) sensing that may render the adult PASMCs more responsive to acute hypoxia.

Calcium sparks in smooth muscle.

Local intracellular Ca(2+) transients, termed Ca(2+) sparks, are caused by the coordinated opening of a cluster of ryanodine-sensitive Ca(2+) release channels in the sarcoplasmic reticulum of smooth muscle cells. Ca(2+) sparks are activated by Ca(2+) entry through dihydropyridine-sensitive voltage-dependent Ca(2+) channels, although the precise mechanisms of communication of Ca(2+) entry to Ca(2+) spark activation are not clear in smooth muscle. Ca(2+) sparks act as a positive-feedback element to increase smooth muscle contractility, directly by contributing to the global cytoplasmic Ca(2+) concentration ([Ca(2+)]) and indirectly by increasing Ca(2+) entry through membrane potential depolarization, caused by activation of Ca(2+) spark-activated Cl(-) channels. Ca(2+) sparks also have a profound negative-feedback effect on contractility by decreasing Ca(2+) entry through membrane potential hyperpolarization, caused by activation of large-conductance, Ca(2+)-sensitive K(+) channels. In this review, the roles of Ca(2+) sparks in positive- and negative-feedback regulation of smooth muscle function are explored. We also propose that frequency and amplitude modulation of Ca(2+) sparks by contractile and relaxant agents is an important mechanism to regulate smooth muscle function.

Regulation of cloned cardiac L-type calcium channels by cGMP-dependent protein kinase.

We have studied the effect of 8-bromo-cyclic GMP (8-Br-cGMP) on cloned cardiac L-type calcium channel currents to determine the site and mechanism of action underlying the functional effect. Rabbit cardiac alpha(1C) subunit, in the presence or absence of beta(1) subunit (rabbit skeletal muscle) or beta(2) subunit (rat cardiac/brain), was expressed in Xenopus oocytes, and two-electrode voltage-clamp recordings were made 2 or 3 days later. Application of 8-Br-cGMP caused decreases in calcium channel currents in cells expressing the alpha(1C) subunit, whether or not a beta subunit was co-expressed. No inhibition of currents by 8-Br-cGMP was observed in the presence of the protein kinase G inhibitor KT5823. Substitutions of serine residues by alanine were made at residues Ser(533) and Ser(1371) on the alpha(1C) subunit. As for wild type, the mutant S1371A exhibited inhibition of calcium channel currents by 8-Br-cGMP, whereas no effect of 8-Br-cGMP was observed for mutant S533A. Inhibition of calcium currents by 8-Br-cGMP was also observed in the additional presence of the alpha(2)delta subunit for wild type channels but not for the mutant S533A. These results indicate that cGMP causes inhibition of L-type calcium channel currents by phosphorylation of the alpha(1C) subunit at position Ser(533) via the action of protein kinase G.

NO causes perinatal pulmonary vasodilation through K+-channel activation and intracellular Ca2+ release.

Evidence suggests that nitric oxide (NO) causes perinatal pulmonary vasodilation through K+-channel activation. We hypothesized that this effect worked through cGMP-dependent kinase-mediated activation of Ca2+-activated K+ channel that requires release of intracellular Ca2+ from a ryanodine-sensitive store. We studied the effects of 1) K+-channel blockade with tetraethylammonium, 4-aminopyridine, a voltage-dependent K+-channel blocker, or glibenclamide, an ATP-sensitive K+-channel blocker; 2) cyclic nucleotide-sensitive kinase blockade with either KT-5823, a guanylate-sensitive kinase blocker, or H-89, an adenylate-sensitive kinase blocker; and 3) blockade of intracellular Ca2+ release with ryanodine on NO-induced pulmonary vasodilation in acutely prepared late-gestation fetal lambs. N-nitro-L-arginine, a competitive inhibitor of endothelium-derived NO synthase, was infused into the left pulmonary artery, and tracheotomy was placed. The animals were ventilated with 100% oxygen for 20 min, followed by ventilation with 100% oxygen and inhaled NO at 20 parts/million (ppm) for 20 min. This represents the control period. In separate protocols, the animals received an intrapulmonary infusion of the different blockers and were ventilated as above. Tetraethylammonium (n = 6 animals) and KT-5823 (n = 4 animals) attenuated the response, whereas ryanodine (n = 5 animals) blocked NO-induced perinatal pulmonary vasodilation. 4-Aminopyridine (n = 5 animals), glibenclamide (n = 5 animals), and H-89 (n = 4 animals) did not affect NO-induced pulmonary vasodilation. We conclude that NO causes perinatal pulmonary vasodilation through cGMP-dependent kinase-mediated activation of Ca2+-activated K+ channels and release of Ca2+ from ryanodine-sensitive stores.

Recruitment strategies in the women's health trial: feasibility study in minority populations. WHT:FSMP Investigators Group. Women's Health Trial:Feasibility Study in Minority Populations.

The Women's Health Trial:Feasibility Study in Minority Populations (WHT:FSMP) examined the feasibility of recruiting postmenopausal women from a broad range of racial and socioeconomic backgrounds into a primary prevention trial requiring marked reductions in dietary fat. Postmenopausal women aged 50-79 yr who had no history of cardiovascular disease or cancer and who consumed 36% or more total energy from fat qualified to participate. We randomized the women into dietary intervention (60%) or control (40%) groups; we aimed to randomize 750 women in 18 months in each of the three clinical centers. All centers achieved goals for randomization based on ethnicity, and two centers exceeded overall recruitment goals. The greatest source of randomized participants was mass mailing, followed by items in the media, referrals, and community outreach. Recruitment yields were generally similar for the ethnic groups but lower for less-educated participants. The experience of WHT:FSMP indicates that postmenopausal women from the African-American, Hispanic, and non-Hispanic white communities can be recruited into dietary intervention studies for the prevention of disease.

Frequency modulation of Ca2+ sparks is involved in regulation of arterial diameter by cyclic nucleotides.

Forskolin, which elevates cAMP levels, and sodium nitroprusside (SNP) and nicorandil, which elevate cGMP levels, increased, by two- to threefold, the frequency of subcellular Ca2+ release ("Ca2+ sparks") through ryanodine-sensitive Ca2+ release (RyR) channels in the sarcoplasmic reticulum (SR) of myocytes isolated from cerebral and coronary arteries of rats. Forskolin, SNP, nicorandil, dibutyryl-cAMP, and adenosine increased the frequency of Ca(2+)-sensitive K+ (KCa) currents ["spontaneous transient outward currents" (STOCs)] by two- to threefold, consistent with Ca2+ sparks activating STOCs. These agents also increased the mean amplitude of STOCs by 1.3-fold, an effect that could be explained by activation of KCa channels, independent of effects on Ca2+ sparks. To test the hypothesis that cAMP could act to dilate arteries through activation of the Ca2+ spark-->KCa channel pathway, the effects of blockers of KCa channels (iberiotoxin) and of Ca2+ sparks (ryanodine) on forskolin-induced dilations of pressurized cerebral arteries were examined. Forskolin-induced dilations were partially inhibited by iberiotoxin and ryanodine (with no additive effects) and were entirely prevented by elevating external K+. Forskolin lowered average Ca2+ in pressurized arteries while increasing ryanodine-sensitive, caffeine-induced Ca2+ transients. These experiments suggest a new mechanism for cyclic nucleotide-mediated dilations through an increase in Ca2+ spark frequency, caused by effects on SR Ca2+ load and possibly on the RyR channel, which leads to increased STOC frequency, membrane potential hyperpolarization, closure of voltage-dependent Ca2+ channels, decrease in arterial wall Ca2+, and, ultimately, vasodilation.

Racial differences in ambulatory blood pressure and echocardiographic left ventricular geometry.

We examined the racial differences in left ventricular (LV) geometric pattern in relation to 24-hour ambulatory blood pressure (BP) monitoring and the presence or absence of a nocturnal BP dip. Our study confirms the blunting of nocturnal BP dip among black hypertensives. Body mass index, rather than race, was a major determinant of left ventricular hypertrophy. We did not observe a difference in prevalence of left ventricular hypertrophy by race. However, left ventricular adaptation to hypertension differed in hypertensive black and white individuals; whereas most of the white patients with Stage 1-2 hypertension had a normal ventricular pattern, LV concentric remodeling and concentric hypertrophy were the most common adaptive ventricular patterns in blacks with Stage 1-2 hypertension. A six-fold higher prevalence of concentric remodeling was observed in blacks as compared with whites. The impaired nocturnal BP dip in blacks may contribute to the different hemodynamic pattern. Determinants of myocardial oxygen consumption were significantly higher in black hypertensives.

Ca2+ channels, ryanodine receptors and Ca(2+)-activated K+ channels: a functional unit for regulating arterial tone.

Local calcium transients ('Ca2+ sparks') are thought to be elementary Ca2+ signals in heart, skeletal and smooth muscle cells. Ca2+ sparks result from the opening of a single, or the coordinated opening of many, tightly clustered ryanodine receptor (RyR) channels in the sarcoplasmic reticulum (SR). In arterial smooth muscle, Ca2+ sparks appear to be involved in opposing the tonic contraction of the blood vessel. Intravascular pressure causes a graded membrane potential depolarization to approximately -40 mV, an elevation of arterial wall [Ca2+]i and contraction ('myogenic tone') of arteries. Ca2+ sparks activate calcium-sensitive K+ (KCa) channels in the sarcolemmal membrane to cause membrane hyperpolarization, which opposes the pressure induced depolarization. Thus, inhibition of Ca2+ sparks by ryanodine, or of KCa channels by iberiotoxin, leads to membrane depolarization, activation of L-type voltage-gated Ca2+ channels, and vasoconstriction. Conversely, activation of Ca2+ sparks can lead to vasodilation through activation of KCa channels. Our recent work is aimed at studying the properties and roles of Ca2+ sparks in the regulation of arterial smooth muscle function. The modulation of Ca2+ spark frequency and amplitude by membrane potential, cyclic nucleotides and protein kinase C will be explored. The role of local Ca2+ entry through voltage-dependent Ca2+ channels in the regulation of Ca2+ spark properties will also be examined. Finally, using functional evidence from cardiac myocytes, and histological evidence from smooth muscle, we shall explore whether Ca2+ channels, RyR channels, and KCa channels function as a coupled unit, through Ca2+ and voltage, to regulate arterial smooth muscle membrane potential and vascular tone.

Myelin protein expression is increased in lymph nodes of mice with relapsing experimental autoimmune encephalomyelitis.

Myelin proteins had been thought to be sequestered behind the blood-brain barrier. Recently, however, myelin proteins have been found to be expressed in lymphoid tissues. The myelin basic protein (MBP) gene is embedded within a larger transcription unit called the golli-MBP gene. This larger gene encodes both the "classic" MBPs as well as the structurally related golli-MBPs. In this study, golli-MBP expression in lymph nodes was examined in four different models of relapsing experimental autoimmune encephalomyelitis (rEAE). Disease in these rEAE models was induced by the adoptive transfer of T lymphocytes specific for 18.5-kDa MBP, MBP peptide 83-102, or PLP peptide 139-151 in the SJL/J mouse and the adoptive transfer of T lymphocytes specific for MBP peptide Ac1-9 in the (SJL/J x PL/J)F1 mouse. In all four models, expression of golli-MBP BG21 mRNA was increased two- to fivefold in lymph nodes of mice 45 to 60 days post-transfer. Immunohistochemical analysis indicated that expression occurred principally in macrophages within lymph nodes. Endogenous golli-MBP epitopes within lymph node cells stimulated "classic" MBP 1-44-specific T lymphocytes, and this stimulatory ability resided within the adherent lymph node cell population. An increase in myelin protein expression within lymph nodes during rEAE has implications with regard to intra- and intermolecular epitope spreading. This is the first report describing an increase in target autoantigen expression within lymphoid tissue during an autoimmune disease.

gamma-Aminobutyric acidA receptors and spinally mediated antinociception in rats.

Experiments were performed on rats with lumbar subarachnoid catheters, using four agonist drugs [gamma-aminobutyric acid (GABA), muscimol, midazolam and 5-hydroxytryptamine (5-HT)] and two GABA(A) antagonists (bicuculline and SR-95531) given intrathecally. All four agonists caused dose-related antinociception assessed by the electrical current threshold test. These effects were spinally mediated because the agonists caused increases in nociceptive thresholds in the skin of the tail and not the neck. In the same experiments, 5-HT and GABA caused simultaneous increases in tail-flick latency and electrical current thresholds in the tail. Both GABA(A) antagonists caused dose-related suppression of the antinociceptive effects of equieffective doses of all four agonists. Tail-flick latency increases caused by 5-HT were not suppressed by bicuculline in the same experiments in which bicuculline had suppressed the electrical current threshold effects of intrathecal 5-HT. The log dose-response curves for both antagonists for suppression of GABA effects were coincident, having a very shallow slope and covering the whole range of doses effective against the other agonists. The two GABA(A) antagonists were very different in relative potency for suppression of the spinally mediated antinociceptive effects of the other three agonists. The rank order of potency for bicuculline suppression of the effects of equieffective doses of the other agonists was muscimol > 5-HT > midazolam, whereas the rank order for SR-95531 was muscimol >> midazolam > 5-HT. We conclude that there exist in the spinal cord at least three different GABA(A) receptors responsible for spinally mediated antinociception caused by intrathecal injections of midazolam, muscimol and 5-HT. These are all targets for endogenous GABA.