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J L Hudson

Publications and source records attributed to J L Hudson.

At least 37 records · Page 2Linked to original sources
PubMed1994

Conditioned apomorphine-induced turning in 6-OHDA-lesioned rats.

Apomorphine-induced turning has been used to evaluate the extent of unilateral nigrostriatal denervation after 6-hydroxydopamine (6-OHDA) lesions and subsequent functional striatal reinnervation by catecholaminergic grafts. It has been noted that the pregraft rotational pattern is usually double peaked and that fetal ventral mesencephalic grafts or dopaminergic drugs will alter the second peak but leave the first relatively unchanged. We hypothesized that the first peak may be the result of factors extrinsic to the nigrostriatal dopamine system, specifically a conditioned turning response, and would, therefore, be unperturbed by the above treatments which increase dopaminergic (DA) inputs. This was investigated by injecting 6-OHDA, unilaterally, into the nigrostriatal pathway of several groups of young Fisher 344 rats. One experimental group was repeatedly tested with 0.05 mg/kg apomorphine and the rotations quantified. A second group received similar injections of apomorphine but were prevented from rotating. Vehicle control animals were also studied for both of the above experimental groups. Subsequent to the above treatment, all animals were tested unrestrained repeatedly on apomorphine. Our results support the conditioned response hypothesis in that the first peak is not present with the initial unrestrained apomorphine behavioral trial but is present upon the second and subsequent unrestrained trials. Moreover, the restrained but apomorphine-injected rats, as well as the control animals, manifest no first peak upon their first freely moving apomorphine test; the second and subsequent unrestrained apomorphine trials, in these groups, do manifest a first peak.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Target and neurotransmitter specificity of fetal central nervous system transplants: importance for functional reinnervation.

The ability of grafted fetal ventral mesencephalic dopaminergic (DAergic) neuroblasts to reinnervate the unilaterally DA denervated rat striatum and improve motoric asymmetry has been well documented in several laboratories. The importance of host target specificity, and catecholamine (CA) neurotransmitter species, in the ability of grafts to ameliorate rotational responses to apomorphine and to affect electrophysiological characteristics of striatal neurons has not been systematically studied. We unilaterally lesioned Sprague-Dawley rats with 6-hydroxydopamine (6-OHDA) and verified the lesions using apomorphine (0.05 mg/kg, s.c.)-induced rotational behavior. Some of the animals subsequently received, intrastriatally, either DA neuroblasts from ventral mesencephalon that normally innervate the striatum, or from arcuate nucleus that do not. Additionally, two other groups were included that received either a CAergic graft from the noradrenergic nucleus locus coeruleus or a graft of cerebral cortex, which normally projects to the striatum but does not contain CAergic neurons. Only the fetal ventral mesencephalic grafts were able to reduce apomorphine-induced rotations and normalize striatal cell firing rates; striatal cell firing rates with ventral mesencephalic grafts were 1.43 Hz +/- 0.22, with arcuate nucleus grafts were 6.03 +/- 0.73, with locus coeruleus grafts were 4.71 +/- 0.74, and with cerebral cortex grafts were 4.36 +/- 0.45. Moreover, only the ventral mesencephalic grafts produced a dense tyrosine hydroxylase (TH)-immunoreactive nerve terminal network in the striatum; in contrast, the arcuate nucleus grafts did not reinnervate the striatum. In locus coeruleus grafted striata, few very long TH-positive axons were seen. We thus conclude that target specificity and neurotransmitter type are critically important in the ability of a graft to functionally reinnervate the 6-OHDA denervated striatum.

Animals↗
PubMed1993

Correlation of apomorphine- and amphetamine-induced turning with nigrostriatal dopamine content in unilateral 6-hydroxydopamine lesioned rats.

In the unilateral 6-hydroxydopamine (6-OHDA)-lesioned rat model of Parkinson's disease, controversy exists concerning the use of apomorphine- or D-amphetamine-induced rotations as reliable indicators of nigrostriatal dopamine depletion. Our objective was to evaluate which, if either, drug-induced behavior is more predictive of the extent of nigrostriatal dopamine depletion. Fischer 344 and Sprague-Dawley rats were unilaterally injected with 9 micrograms/4 microliters/4 min 6-hydroxydopamine into the medial forebrain bundle. The animals were behaviorally tested with apomorphine (0.05 mg/kg, s.c.) and D-amphetamine (5.0 mg/kg, s.c.). Following testing, the brains were removed and the right and left striata, substantia nigra and ventral tegmental area were dissected free and quickly frozen at -70 degrees C for analysis of catecholamine content by high performance liquid chromatography coupled with electrochemical detection. Our results indicate that an animal which has greater than a 90% depletion of dopamine in the striatum might not rotate substantially on apomorphine, without a concomitant depletion of > 50% of the DA content in the corresponding substantia nigra. No correlations were seen involving depletions of the ventral tegmental area and the extent of the lesions to the striatum. Submaximally lesioned (75-90% depleted) rats were found to rotate on D-amphetamine but not on apomorphine. In addition, control rats that did not receive lesions were often seen to rotate extensively on D-amphetamine. We therefore conclude that maximal lesions of the striatum and substantia nigra are required to generate rotations demonstrable with low dose apomorphine but not with D-amphetamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Amphetamine↗
PubMed1993

Clinical estimate of birth-weight in labour: factors influencing its accuracy.

Clinical assessments of birth-weight were made among 88 parturients at term, to determine what maternal and neonatal factors influence the accuracy of predicting neonatal weight. An estimate within +/- 10% of actual weight was considered accurate, while a prediction off by more than 10% was classified as inaccurate. Seventy-one per cent (63 of 88) of the estimates were considered accurate and 28% (25 of 88) inaccurate. Among these 2 groups of patients, univariate analysis did not identify maternal age, gravidity, parity, gestational age, maternal height, prepregnancy weight and maternal body mass index, maternal weight and maternal body mass index at the time of delivery, change in body mass index during pregnancy, intrapartum amniotic fluid index, newborn's weight, length, and ponderal index as being significant correlates of an accurate clinical estimate of the birth-weight. Over 2 years, as the provider gained experience in predicting the neonatal weight, the accuracy of the clinical estimate of birth-weight did not improve.

Adult↗
PubMed1991

Functional innervation of spinal cord tissue by fetal neocortical grafts in oculo: an electrophysiological study.

The ability of fetal neocortex transplants, to functionally innervate maturated cervical spinal cord grafts in oculo, was investigated in rats. We found that a neocortex co-graft will grow and develop in contact with a spinal cord graft, and will generate a functional input to maturated spinal cord tissue which can be activated by electrical stimulation of the neocortex graft. Our data suggest that orthodromic stimulation of this pathway causes short latency, transient excitations of spinal graft neurons. These appear to be mediated by an excitatory amino acid receptor since the response was noncompetitively antagonized by kynurenic acid. Kynurenic acid also noncompetitively antagonized the excitatory effects of glutamate superfused over single spinal cord grafts. The mechanism of the excitation probably does not involve an NMDA (N-methyl-D-aspartate) receptor since APV (2-amino-5-phosphonovalerate) did not alter the spinal graft neuronal responses to neocortical co-graft stimulation. These data suggest that fetal neocortex can functionally innervate maturated cervical spinal cord in the in oculo graft preparation. The in oculo spinal cord graft model may thus provide a unique test system for studies of the influence of drugs and other manipulations that might alter cortico-spinal pathway development as well as influence reestablishment of neuronal pathways after spinal cord injury.

Action Potentials↗
PubMed1991

Activity of acyclic halogenated tubercidin analogs against human cytomegalovirus and in uninfected cells.

Novel acyclic halogenated tubercidins (4-amino-5-halo-7-[(2-hydroxyethoxy)-methyl]pyrrolo[2,3-d]pyrimidines) were examined for their ability to inhibit human cytomegalovirus (HCMV) in yield reduction assays. 5-Bromo acyclic tubercidin (compound 102) was a more potent inhibitor of virus replication than the chloro- and iodo-substituted analogs (compounds 100 and 104). At a 100 microM concentration, the bromo and chloro compounds were more potent than acyclovir but not ganciclovir. Virus titers were reduced more than 99% by compounds 102 and 104 whereas compound 100 and the equally potent acyclovir reduced titers by only 90%. Quantitation of viral DNA by DNA hybridization demonstrated strong inhibition of HCMV DNA synthesis by these compounds. The most potent inhibitor, compound 102, had a 50% inhibitory (I50) concentration (1.6 microM) comparable to that of ganciclovir (1.8 microM). Cytotoxicity in uninfected human cells was evaluated and revealed the following: cell growth rates slowed markedly in the presence of 10 microM compound 102 whereas the same concentration of compounds 100 and 104 led to only a slight prolongation of population doubling time; these compounds inhibited cellular DNA synthesis but not RNA or protein synthesis, as measured by incorporation of radiolabeled precursors into acid-precipitable macromolecules; flow cytometry indicated that compound 102 was a mid-S phase blocker, and adenosine antagonized the inhibition of [3H]dThd incorporation by compound 102. Together, these results demonstrate that compound 102 is a potent and selective inhibitor of viral and cellular DNA synthesis and that acyclic halogenated pyrrolo-pyrimidine nucleosides may have therapeutic potential.

Adenosine↗
PubMed1991

Flow cytometric analysis of human erythrocytes: I. Probed with lectins and immunoglobulins.

A recent review (Aminoff, 1988) summarized the evidence for and against our hypothesis for the role of glycophorin in the senescence and clearance of mammalian red blood cells (RBC) from circulation. This hypothesis postulates the loss of sialic acid from RBC surface in two forms: (a) as vesicles containing the sialoglycoprotein glycophorin, and (b) as free sialic acid residues from glycophorin molecules remaining on cell surface. In this report we demonstrate the applicability of flow cytometric procedures to explore, at the cellular level, time-dependent changes on RBC surface with change in cell size, and with in vivo age. The RBC are probed with fluorescein isothiocyanate (FITC) labelled lectins and goat anti-human-IgG and -IgM. The relative intensity of fluorescence is correlated to the change in RBC size as measured by forward lightscatter. Reactivity of RBC with FITC-labelled wheat germ agglutinin can be inhibited with either 0.2M N-acetylglucosamine or by removal of sialic acid residues with neuraminidase. The properties of the smallest RBC correspond to those of the oldest RBC in their: (a) decreased reactivity with FITC-labelled lectins that recognize sialic acid residues, wheat germ and Limax flavus agglutinins, and (b) increased reactivity with FITC-labelled goat anti-human-IgG and -IgM. These results are compatible with our glycophorin hypothesis. Moreover, they suggest that the initial loss of sialic acid as glycophorin containing vesicles is gradual, while the subsequent step involving the loss of sialic acid residues is rapid and exposes multiple disaccharide galactose beta(1-3)N-acetylgalacosaminyl residues. These unmasked disaccharide sites are recognized by autoimmune IgG, IgM, and lectin-like receptors on macrophages resulting in the clearance of senescent RBC from circulation.

Erythrocyte Membrane↗
PubMed1990

Flow cytometric evaluation of the cytotoxicity of novel antiviral compounds.

Two acyclic analogs of bromotubercidin were tested for cytotoxic effects on uninfected cells by monitoring cell growth and measuring cell cycle perturbations using flow cytometry. As reported elsewhere, 5-bromotubercidin analogs in which ribose was replaced by 2-hydroxyethoxymethyl (compound 102) or by 1,3-dihydroxypropoxymethyl (compound 183) were potent inhibitors of human cytomegalovirus (HCMV) replication in vitro (Pudlo et al.: Journal of Medicinal Chemistry 31:2086-2092, 1988). Because these compounds also inhibited the growth of uninfected cells, we performed kinetic studies with an established neoplastic line of human cells (KB) using flow cytometry. Growth of KB cells treated with either compound 102 or 183 were inhibited in a dose-dependent manner. Growth inhibition by compound 183, however, was not fully expressed for at least 24 h. DNA analysis by flow cytometry showed that a 4-h incubation with 10 microM compound 102 caused a decrease of cells in G2/M phase. Cells began to accumulate in early S phase by 12 h of incubation, leading to mid S phase accumulation at 21 h. Compound 183 at 10 microM slightly decreased the number of cells in G2/M phase after a 4-h incubation, and led to accumulation of DNA in S phase after a 12-h incubation. By 24 and 30 h, DNA histograms appeared similar to those of control cells but with a slight accumulation of the population in early S phase. In separate experiments, drugs were removed following a 24-h incubation. After removal of compound 102, KB cell growth resumed with a normal population doubling time. In contrast, the effects of compound 183 were not reversible, suggesting the two compounds acted by different biochemical mechanisms.

Antiviral Agents↗
PubMed1990

CD4+ cells treated with DNA methylation inhibitors induce autologous B cell differentiation.

The DNA methylation inhibitor 5-azacytidine induces autoreactivity in cloned CD4+ T cells, but the functional consequences of this response are unknown. We now report that CD4+ T cells treated with 5-azacytidine respond to autologous antigen-presenting cells and induce autologous B cell differentiation without exogenous antigen or mitogen. This mechanism could play a role in some autoimmune diseases characterized by T cell DNA hypomethylation and polyclonal B cell activation.

Acecainide↗
PubMed1989

Flow cytometric analysis of lymphocyte subpopulations in infants with congenital heart disease.

Premortem diagnosis of the DiGeorge syndrome and its partial variants relies on the demonstration of a primary defect in cell-mediated immunity, generally in the setting of an infant with congenital heart disease, hypocalcemia, absence of a thymic shadow, and typical dysmorphic features. Although T-cell enumeration is considered a vital part of the diagnostic evaluation, no studies to date have addressed the issue of appropriate reference data in infants with congenital heart disease. We therefore undertook a prospective descriptive study of lymphocyte phenotype analysis in 27 nontransfused infants undergoing diagnostic cardiac catheterization. Striking differences were seen between patients and adult controls in means percentages and numbers of most lymphocyte subsets analyzed. Few differences were found in comparing the patient data to values for age-matched control infants without heart disease. The data are discussed with reference to published values for patients with partial DiGeorge syndrome. It is concluded that lymphocyte phenotype analysis in the diagnostic evaluation of patients with suspected DiGeorge syndrome must utilize appropriate reference values.

Antigens, Differentiation↗
PubMed1988

Flow cytometric measurements of nuclear DNA and ploidy analysis in Hürthle cell neoplasms of the thyroid.

Nuclear DNA content and nuclear DNA ploidy were measured in 36 Hürthle cell neoplasms (HCNs) to better define their potential roles in predicting the clinical behavior of these lesions. An EPICS V flow cytometer (Coulter Electronics, Hialeah, Fla) was used. Measurements were taken from paraffin-embedded tissue. Isolated nuclei were stained with propidium iodide. The study was conducted in a blinded fashion. Observed NDC and PDY patterns were classified as diploid, aneuploid, or suspicious. Twenty-nine lesions (81%) were diploid and seven (19%) were aneuploid. Twelve (33%) HCNs were malignant, 23 (64%) were benign, and one (3%) was indeterminate. Eight (67%) of 12 malignant HCNs were diploid and four (33%) of 12 were aneuploid. In comparison, 20 (87%) of 23 benign lesions were diploid and three (13%) of 23 were aneuploid. The indeterminate neoplasm was diploid. There were three deaths in this group of patients; all three had aneuploid neoplasms, and all had locally recurrent disease with distant metastases. There was a significant cross correlation between histologic features and DNA content with regard to outcome. These preliminary data suggest that NDC and PDY are not helpful in distinguishing histologically benign from malignant HCNs; however, they may be useful in determining prognosis.

Adenoma↗
PubMed1988

Measurement of intracellular fluorescence of human monocytes relative to oxidative metabolism.

Human monocytes (MN) produce O2- and H2O2 when stimulated by agonists. Dichlorofluorescin diacetate (DCFH-DA) has been used as a substrate for measuring intracellular oxidant production in neutrophils. DCFH-DA is hydrolyzed by esterases to dichlorofluorescin (DCFH), which is trapped within the cell. This nonfluorescent molecule is then oxidized to fluorescent dichlorofluorescin (DCF) by action of cellular oxidants. DCFH-DA can not be appreciably oxidized to a fluorescent state without prior hydrolysis. We have examined the utility of DCFH-DA for the assessment of monocyte oxidative responses. The levels of intracellular fluorescence measured by flow cytometry were considerably less than expected from reported levels of O2--production or chemiluminescence assays. Compared with neutrophils, monocytes produced minimal increases in DCF fluorescence after stimulation with phorbol myristate acetate as measured by flow cytometry, but both cell types showed increases in fluorescence when bulk cell suspensions were measured by spectrofluorometry. To determine the intracellular location of the DCFH, bulk fluorescence measurements were made on both whole and sonicated cell preparations. When intact mononuclear cells were preloaded with DCFH-DA, then sonicated and oxidized with added excess H2O2, the increase in fluorescence was only 30% of the fluorescence of mononuclear cell sonicates to which DCFH-DA was added and oxidized in a similar manner. These results suggest that a portion of the DCFH-DA incorporated by intact cells, is not susceptible to oxidation by the added H2O2. Addition of NaOH to induce hydrolysis of any residual DCFH-DA in the sonicates of DCFH-DA-loaded intact mononuclear cells resulted in a further increase in fluorescence upon addition H2O2, suggesting that a significant portion of the DCFH-DA was not hydrolyzed despite ample uptake of this dye by these cells. In contrast, no further increase in fluorescence was observed in sonicates of DCFH-DA-loaded intact neutrophils, suggesting complete hydrolysis of all incorporated DCFH-DA to DCFH. When monocytes were allowed to phagocytose DCFH-DA-loaded Staphylococcus aureus, intracellular fluorescence was measurable by flow cytometry, indicating intracellular oxidation of the fluorochromes. We therefore propose that in monocytes the mechanism of intracellular processing of these fluorochromes differs from that in neutrophils owing to differences in intracellular localization of fluorochromes, site of oxidant production, and/or accessibility of the DCFH-DA to esterolysis.

Esterases↗
PubMed1988

Reduced oxidative function in gingival crevicular neutrophils in periodontal disease.

Measurable amounts of viable and functional polymorphonuclear neutrophils (PMNs) are recovered from pooled washings of the gingival crevice of healthy individuals. In the present study, we have assessed the ability of the PMNs removed from single healthy or diseased pocket sites to mount an oxidative burst when challenged with phorbol myristate acetate (PMA) and compared these activities with each other and with those obtained with autologous peripheral-blood PMNs. The oxidative burst after PMA stimulation was evaluated by using methods developed for the flow cytometer. The results showed that the PMNs collected from untreated disease sites were minimally responsive to PMA when compared with peripheral-blood PMNs collected at the same time from the same individual. Thus, whereas the peripheral-blood PMNs exhibited significantly lower resting oxidative product formation and a 500% increase when stimulated with PMA, all gingival-crevicular PMNs exhibited significantly higher resting formation of oxidized products but only a 150% increase after PMA stimulation. PMNs obtained from a consistently healthy site had significantly higher resting production of oxidized products and were able to mount the greatest absolute increase in oxidized products after PMA stimulation when compared with PMNs collected from diseases sites. Mechanical debridement of these diseased sites, which both reduced the bacterial numbers and restored clinical health, resulted in the recovery of gingival-crevicular PMNs that exhibited an oxidative burst more typical of that observed in PMNs obtained from healthy gingival sites and from the peripheral blood. This suggested that the PMNs collected from the diseased sites either had been exhausted by the large numbers of bacteria present in these sites or had been specifically inhibited by these bacteria.

Debridement↗
PubMed1988

Lymphocyte phenotyping of infants with congenital heart disease: comparison of cell preparation techniques.

The diagnostic evaluation of infants with suspected DiGeorge syndrome includes peripheral blood lymphocyte phenotype analysis by flow cytometry. Mononuclear cells are typically concentrated from infants' blood samples by Ficoll-Hypaque (FH) density gradient centrifugation prior to monoclonal antibody (Mab) staining. Having observed that lymphocyte percentages in samples prepared by this technique were low more often than anticipated based on the prevalence of the suspected diagnosis, we undertook a prospective study of 55 infants with congenital heart disease comparing FH with a whole-blood (WB) technique. Sixty healthy adult controls were similarly studied. We report the observation that FH-prepared mononuclear cells from blood samples of infants less than 4 months of age yield substantially different phenotypes than WB-prepared samples. The differences are related to red blood cell (RBC) contamination. No such difference was seen with adult samples. Unlike FH-prepared adult samples, contaminating RBCs are indistinguishable from lymphocytes through at least 4 months of age when assessed by the standard cytometric gating parameters of forward and 90 degrees light scatter. The use of a WB ammonium chloride lysis technique is recommended as most appropriate for the preparation of infants' blood samples.

Antigens, Surface↗
PubMed1987

Measurement of antineutrophil antibodies by flow cytometry: simultaneous detection of antibodies against monocytes and lymphocytes.

We describe a flow cytometric technique which detects the presence of antineutrophil antibodies (NABs) in human serum. The technique provides a qualitative as well as a semiquantitative screen and provides an excellent method for monitoring the presence of antineutrophil antibodies in patients with suspected autoimmune neutropenia. Using light-scatter gating, individual populations consisting of neutrophils, monocytes, and lymphocytes can be examined simultaneously for the presence of antibody. The methodology utilizes an indirect immunofluorescence technique with FITC-labeled goat antihuman F(ab')2 antibody and fixed leukocyte suspensions. Furthermore, by utilizing class-specific FITC-labeled second antibody, significant information can be ascertained regarding the class, cell specificity, and quantity of detected antibody. Formalin fixation of neutrophils prevented pinocytosis of the fluorochrome, significantly reducing background fluorescence. Twenty-five normal subjects provided baseline antibody levels for each class. Of 92 patients with suspected autoimmune neutropenia, 27 had class IgG alone and seven were positive for both IgG and IgM class NABs. During treatment, IgG levels varied. IgM NABs alone were detected in four patients. Fifty-four patients had undetectable antibody. Antibodies were detected against monocytes in several of the IgG-positive patients. Two sera contained both IgA and IgG NABs. One serum contained IgA and IgG antibodies against monocytes. No IgD antibodies were detected in any sera tested. Some sera tested contained antibodies against lymphocytes--however, only in those sera which also contained antibodies to other cell types.

Autoantibodies↗
PubMed1986

Products of cells cultured from gliomas. IV. Extracellular matrix proteins of gliomas.

Five primary and 3 established human glioma cell lines were cultured with ascorbate and examined for expression of extracellular matrix components. All lines except C6 expressed collagen as assessed by silver impregnation, immunofluorescence and lectin staining and expressed laminin and fibronectin. None expressed a lectin marker for endothelial cells. Both epithelial and mesenchymal collagens were expressed. While extracellular components of glioma lines resembled those of fibroblasts more closely than other cell types, subtle differences between gliomas and fibroblasts were present. These included more laminin and collagen type-IV antigenic reactivity and more 11-12 nm diameter extracellular fibrils from individual gliomas, and slight differences in spectra of low-molecular-weight extracellular proteins assessed by gel electrophoresis. One primary and two established glioma lines analysed for DNA content were aneuploid in contrast to diploid fibroblasts. Simultaneous expression of mesenchymal and epithelial markers suggests a dual differentiation potential of glioma cells. Results do not support an endothelial origin for cells cultured from gliomas.

Carbohydrates↗
PubMed1986

In vitro and in vivo cytotoxicity of T cells cloned from rejecting allografts.

Epa-1 is a tissue-restricted, non-major histocompatibility (MHC) antigen that may be responsible for the extreme sensitivity of skin to allograft rejection and graft-versus-host disease (GVHD), especially with MHC-compatible donors and recipients. To confirm that Epa-1 serves as a target in allograft rejection and GVHD, we isolated Epa-1-specific cytotoxic T lymphocyte (CTL) clones completely in vivo from sponge-matrix allografts and from lymph nodes draining rejecting skin allografts. These clones induced GVHD-like skin lesions in antigen-specific, MHC-restricted fashion following intradermal inoculation into appropriate hosts. The in vivo-derived clones are conventional CTL since they are IL-2-dependent and express the Thy-1.2+, Lyt-1-, Lyt-2+, L3T4- phenotype. The results of this study also are pertinent to the controversy over which T-cell subset actually mediates allograft immunity, since the intragraft isolation and subsequent cloning of conventional CTL that induce necrotizing skin lesions are direct evidence that CTL are the proximal mediators of allograft rejection.

Animals↗