Biochemical actions of chronic ethanol exposure in the mesolimbic dopamine system

In previous studies, we have demonstrated that chronic administration of morphine or cocaine produces some common biochemical adaptations in the ventral tegmental area (VTA) and nucleus accumbens (NAc), components of the mesolimbic dopamine system implicated in the reinforcing actions of these and other drugs of abuse. Since this neural pathway is also implicated in the reinforcing actions of ethanol, it was of interest to determine whether chronic ethanol exposure results in similar biochemical adaptations. Indeed, as seen for chronic morphine and cocaine treatments, we show here that chronic ethanol treatment increased levels of tyrosine hydroxylase and glial fibrillary acidic protein immunoreactivity, and decreases levels of neurofilament protein immunoreactivity, in the VTA. Also like morphine and cocaine, ethanol increases levels of cyclic AMP-dependent protein kinase activity in the NAc. These actions of ethanol required long-term exposure to the drug, and were in most cases not seen in the substantia nigra or caudate-putamen, components of the nigrostriatal dopamine system studied for comparison. Altered levels of tyrosine hydroxylase in catecholaminergic cells frequently reflect altered states of activation of the cells. Moreover, increasing evidence indicates that ethanol produces many of its acute effects on the brain by regulating NMDA glutamate and GAB_A receptors. We therefore examined the influence of chronic ethanol treatment on levels of expression of specific glutamate and GABA receptor subunits in the VTA. It was found that long-term, but not short-term, ethanol exposure increased levels of immunoreactivity of the NMDARl subunit, an obligatory component of NMDA glutamate receptors, and of the Glu Rl subunit, a component of many AMPA glutamate receptors; but at the same time, long-term ethanol exposure decreased immunoreactivity levels of the α1 subunit of the GABA_A receptor complex. These changes are consistent with an increased state of activation of VTA neurons inferred from the observed increase intyrosine hydroxylase (TH) expression. These results demonstrate that chronic ethanol exposure results in several biochemical adaptations in the mesolimbic dopamine system, which may underlie prominent changes in the structural and functional properties of this neural pathway related to alcohol abuse and alcoholism. © 1995 Wiley-Liss, Inc.     

Myofascial wrap to treat intractable urinary incontinence in children

Objectives. The management of intractable urinary incontinence in the patient with cloacal or bladder exstrophy/epispadias, failed bladder neck plasty, or failed augmentation cystoplasty remains a surgical challenge. The myofascial wrap, a modification of the rectus fascial wrap, was developed to treat intractable urinary incontinence due to sphincteric incompetence in these problematic cases. A full-thickness, vascularized pedicle of anterior rectus sheath, rectus abdominis muscle, and posterior rector sheath is incorporated into a bladder neck wrap to provide support, mucosal coaptation, and active muscular tone.Methods. Eight patients (5 females and 3 males) with total urinary incontinence due to sphincteric incompetence underwent the myofascial wrap. Urinary tract pathology included cloacal exstrophy (2), female epispadias (2), classic bladder exstrophy (1), male epispadias (1), myelomeningocele (1), and a pelvic tumor (1). The procedure is performed by harvesting a full-thickness strip of pedicled rectus muscle along with the anterior and posterior fascial sheaths. The strip is passed underneath and then over the bladder neck in a near 360° wrap. The free end of the wrap is anchored into the pubic bone in an ipsilateral subperiosteal pouch.Results. Six of the 8 patients are completely continent, and 2 patients void spontaneously without the need for catheterization.Conclusions. The myofascial wrap provides support, mucosal coaptation, and muscular tone to an incompetent sphincter and bladder neck. Favorable results in a very difficult population of pediatric patients warrant its continued use.     

Trauma: a systematic approach to management

Initial care of the trauma victim begins at the scene of the accident, where the "load and go" principle is applied. A systematic approach to management of the trauma victim improves patient outcome. After insertion of an airway and stabilization of the spine, hemorrhage is treated and volume is replaced. At this point, invasive techniques, such as chest tube insertion, peritoneal lavage and pericardiocentesis, may be therapeutic as well as diagnostic.     

Direct visualization and cellular localization of D1 and D2 dopamine receptors in rat forebrain by use of fluorescent ligands.

The regional and cellular localization of the two subtypes of dopamine receptors, D1 and D2, have been ascertained in rat forebrain by use of fluorescent dopaminergic antagonist ligands. (R,S)-5-(4'-aminophenyl)-8-chloro-2,3,4,5-tetrahydro-3- methyl-[1H]-3-benzazepin-7-ol, the 4'-amino derivative of the high-affinity D1-specific antagonist SCH 23390, and the D2 selective antagonist N-(p-aminophenethyl)spiperone were chemically derivatized using the fluorescent compound tetramethylrhodamine. The modification of these antagonist ligands has allowed the specific, cellular resolution of the D1 and D2 receptor binding sites in intact, highly organized regions of forebrain slices in a very rapid experimental time frame. The regional localization of receptors labeled by the fluorescent probes is in agreement with previous receptor autoradiography studies. Moreover, the specific cellular binding patterns for both receptors can now be compared and contrasted to one another in the same tissue by using these fluorescent ligands. D1 receptor sites are most evident within the striatum and exhibit regions of intense "patch" fluorescence corresponding to receptor reactivity in cells and their processes. The distribution of D1 receptor binding is highly analogous to the pattern of dopamine terminal histofluorescence in the caudate nucleus. D2 receptor sites are less prevalent overall and may be localized to a subpopulation of the D1 fluorescent neurons in the caudate nucleus and nucleus accumbens regions.     

Evaluation of the offer vs. serve option within self-serve, choice menu lunch program at the elementary school level

The feasibility of a centralized menu and the effectiveness of an "offer vs. serve" option within a self-serve, choice menu lunch program at the elementary school level were determined. Student trays (no. = 370/day) were visually evaluated for foods chosen and consumed. The same 1-week menu was served at two urban Southern schools. One represented a high-poverty-area, all-black-student school and the other represented a middle-income-area school with a white to black student ratio of 3:1. Students were able to choose the required USDA minimal number of three foods, and 66% of the foods selected were similar at the two schools, demonstrating that a centralized menu was feasible. Three-fourths of the students were able to choose more than 75% of one-third of the RDA for all nutrients except pyridoxine and ascorbic acid at both schools and iron at the high-poverty school. Twenty-five percent or more of the students did not consume 75% of one-third the Recommended Dietary Allowance for thiamin, vitamin B-6, ascorbic acid, iron, and magnesium at either school or of niacin and vitamin A at the middle-income school. Overall plate waste was 12.9%, with younger children wasting more food than older children and more waste in the middle-income than the high-poverty school. In general, the "offer vs. serve" was an effective option.     

Improving the management of bladder cancer with fluorescence cystoscopy.

Endoscopic visualization (cystoscopy) and transurethral resection are effective, well-tolerated diagnostic and treatment techniques for bladder cancer. However, it is widely recognized that cystoscopy can miss biologically important lesions, such as carcinoma in situ. Attempts to improve the effectiveness of cystoscopy are not new, but initial methods were impractical and had limited efficacy. Fluorescence cystoscopy became feasible with the discovery that intravesical administration of aminolevulinic acid (ALA) made bladder cancers fluoresce when exposed to blue light. More recently, the creation of a hexyl ester of ALA (HAL) made this technique practical, because HAL significantly shortens the amount of time needed for drug exposure prior to cystoscopy. Not surprisingly, studies have shown that fluorescence cystoscopy can reveal carcinoma in situ that is visually occult under conventional (white-light) cystoscopy. An unexpected finding was that fluorescence cystoscopy also enhanced the detection of papillary tumors. Studies with ALA have shown that resection of bladder cancer with fluorescence results in improved disease-free survival compared to conventional resection under white light. This report summarizes some of the recent studies of fluorescence cystoscopy in bladder cancer.     

Clinical utility of an enhanced human immunodeficiency virus type 1 p24 antigen capture assay

The presence of p24 core antigen in the serum of individuals with human acquired immunodeficiency syndrome has been used as one of the important prognostic markers of HIV-1 infection and also as an end point in evaluating antiviral drugs and vaccines. Unfortunately the majority of p24 antigen present in serum exists as an antigenantibody complex and is not detected with the commercial kits currently available to measure p24 antigen. In this study, we report a simple procedure utilizing treatment of serum samples with glycine buffer (pH 1.85) to dissociate antigen-antibody complexes prior to assaying for p24 antigen. A 300% increase in the number of p24-reactive samples and a 3- to 12-fold increase in the quantity of antigen detected were observed when samples were pretreated with 1.5M glycine buffer (pH 1.85) for 1 hr. Glycine treatment of samples did not result in nonspecific positive tests and samples previously shown to be reactive remained positive. In reconstruction experiments the release of antigen was found to be inversely proportional to the amount of p24 antibody present in the serum. The percentage of HIV-1-infected patients positive for p24 antigen was clearly a function of CD4 count. Forty-nine percent of patients with more than 500 CD4 cells and 100% of patients with less than 200 CD4 were p24 positive. The improved sensitivity for detection of p24 provided by this procedure enhances our understanding of the pathogenesis of AIDS by showing that the majority of patients with HIV-1 infection is p24 positive and facilitates the analysis of data obtained in clinical trials involving anti-HIV compounds.     

Isolation of human complement subcomponents C1r and C1s in their unactivated, proenzyme forms

We have modified a standard isolation procedure for C1r and C1s, which employs IgG-Sepharose affinity chromatography followed by DEAE chromatography. As usual, all steps were performed at low temperature and two proteolytic inhibitors, PMSF and NPGB, were added during affinity chromatography on IgG-Sepharose. The novel condition was to keep the pH at pH 6.1 during the entire procedure, where activation was markedly depressed. In addition, purification was improved by washing the IgG-Sepharose column with a buffer free of added divalent cations immediately prior to elution of the C1r and C1s with EDTA. The final yields of highly purified C1r and C1s were about 20%; little or no activated material was detected in these highly purified fractions.     

CD40 ligand-independent B cell activation revealed by CD40 ligand-deficient T cell clones: evidence for distinct activation requirements for antibody formation and B cell proliferation

We report the capacity of CD40 ligand (CD40L)-negative T cell clones to activate human B cells. CD40L-negative T cells induce a level of B cell proliferation 10–20% of that seen with normal T cells. The signal provided by the negative clones is synergistic with that derived from a CD40L transfectant, and restores B cell proliferation to normal levels, showing that CD40L-negative T cell clones are not inherently inhibitory for B cells. Although their capacity to induce proliferation was much reduced, CD40L-negative T cell clones were still strong inducers of B cell differentiation to plasma cells. This differentiation to plasma cells was inhibited by a CD40L transfectant. The data are discussed with regard to the normal in vivo mechanism for maintaining B cell memory and memory antibody responses to T-dependent antigens.     

Effects of CD8 depletion on retinal soluble antigen induced experimental autoimmune uveoretinitis.

During the later stages of soluble-antigen (sAg)-induced experimental autoimmune uveoretinitis (EAU), an increase in the relative number of CD8+ lymphocytes has been observed at the site of inflammation in the retina. It has been suggested that these late-appearing CD8+ cells might down-regulate this acute disease process. To determine the role of the CD8+ cells in EAU, Lewis rats were depleted of CD8+ cells prior to and during disease and the enucleated eyes examined histologically. The spleen cells from CD8-depleted rats were also examined for their ability to respond to concanavalin A (Con A) and to allogeneic targets as determined by mixed lymphocyte reaction (MLR) and cytotoxicity assays. The results suggest that depleting CD8+ cells had no effect on the course of disease and that CD8+ cells do not play a crucial role in the immunoregulation of EAU.