PubMed Health⌕ Search

Biomedical subjects

A R Pachner

Publications and source records attributed to A R Pachner.

At least 37 records · Page 2Linked to original sources
PubMed1995

Inoculation of nonhuman primates with the N40 strain of Borrelia burgdorferi leads to a model of Lyme neuroborreliosis faithful to the human disease.

We injected rhesus macaques with a highly infective strain of Borrelia burgdorferi to assess whether experimentally inoculated nonhuman primates (NHPs) could serve as models of human Lyme neuroborreliosis (LNB). The animals developed biopsy-confirmed erythema migrans in the area of the inoculations. ELISA testing of sera revealed strong antibody reactivity to B burgdorferi antigens, and Western blotting showed that 16-, 22-, 31-, 34-, and 41-kd proteins of the spirochete were major antigens recognized by antibody. Culture and polymerase chain reaction (PCR) testing of serial CSF specimens revealed that chronic infection of the CNS occurred in all NHPs injected. CSF pleocytosis occurred concurrently with CNS infection. Brain MRI revealed intense meningeal inflammation in one NHP as manifested by gadolinium uptake by the dura at the base of the temporal lobes. All animals had measurable antibody in the CSF after invasion. These studies are the first to demonstrate that experimental LNB in NHPs is a reliable model faithful to the human disease, with spirochetal invasion of the subarachnoid space. This also is the first report of CSF samples positive by culture in experimental LNB. Inflammation in the CNS as manifested by CSF pleocytosis and MRI findings was also correlated with the presence of spirochetal DNA detected by PCR. These data support the hypothesis that the pathogenesis of LNB is associated with direct spirochetal invasion, and provide evidence that CNS involvement is more common than heretofore thought.

Animals↗
PubMed1995

Localization of Borrelia burgdorferi in murine Lyme borreliosis by electron microscopy.

Lyme borreliosis is a newly recognized systemic infection with protean clinical manifestations. Because the localization of the causative spirochete (Borrelia burgdorferi) in infected tissues is unknown, we used electron microscopy to find spirochetes in the hearts of chronically infected mice. There were three predominant locations for the spirochete in the hearts. In mice infected for one month or less, the spirochetes were mostly in or around blood vessels. They were either in the lumen or in the perivascular space. Mice infected for more than one month had B. burgdorferi in cardiac myocytes as well, often with clear spaces around them. The third area in which spirochetes were common was collagen fibers; the borreliae were wrapped around fibers with their long axis parallel to the fibers. The number of spirochetes was relatively low, but there was no appreciable decrease in numbers of spirochetes with increasing time postinfection. Inflammatory infiltrates were primarily in the endocardium and pericardium, but spirochetes were generally not in or near areas of inflammation. These data are consistent with previously published information that have identified the heart as a site of chronic infection and inflammation in the mouse. The studies extend our understanding of the behavior of the spirochete in vivo by identifying common locations of B. burgdorferi and by noting the disparity between infection and inflammation.

Animals↗
PubMed1994

Profile of the regions of acetylcholine receptor alpha chain recognized by T-lymphocytes and by antibodies in EAMG-susceptible and non-susceptible mouse strains after different periods of immunization with the receptor.

C57BL/6 (B6) mice develop a neuromuscular disease, experimental autoimmune myasthenia gravis (EAMG), after two or more immunizations with Torpedo californica acetylcholine receptor (AChR). To determine whether EAMG is related to recognition of particular region(s) on the main extracellular domain of the alpha chain (residues alpha 1-210) in prolonged immunization, we have examined the differences in the antibody and T cell recognition profiles of B6 and SJL (a strain that does not develop EAMG) mice after different periods and a number of immunizations with Torpedo AChR. In a given strain, antibodies and T cells recognized immunodominant regions, which may coincide or may be uniquely B cell or T cell determinants. Both B6 and SJL exhibited similar antibody recognition profiles after the second and through the fourth immunizations with AChR. Major differences between the two strains were found in their T cell recognition of regions in the second part (residues 100-210) of the main extracellular domain of the alpha chain. T cells of SJL recognized consistently only one region (111-126) within this part of the alpha chain, whereas in B6, T cell recognition of three peptides (111-126, 146-162 and 182-198) and next neighbor regions to them persisted throughout the period. Of these three peptides, 146-162 was an immunodominant peptide unique to B6, as the other two peptides (111-126 and 182-198) were also recognized by either T cells or antibodies in SJL. To study the role of the T cells recognizing region 146-162 in EAMG, a T cell line was generated against this region and the cells transferred into B6 mice followed by one Torpedo AChR injection. Enhancement of antibody production toward alpha chain peptides was observed as an influence of T cell transfer compared to profiles at 1 week. In addition, one out of three mice examined showed signs of EAMG. These results suggest the importance of T cells recognizing residues 146-162 in EAMG. It is concluded that the presence of persistent T cell responses to the second half (residues (100-210) of the main extracellular domain of the alpha chain is associated with the development of EAMG in B6 mice, while absence of these responses in SJL mice may enable them to escape the disease. The preservation of the immunodominance of peptide 146-162 in the T cell recognition of B6 is probably most important for the pathogenesis of EAMG in this strain.

Amino Acid Sequence↗
PubMed1994

Spirochetal diseases of the nervous system.

Neurosyphilis and neuroborreliosis are currently the most important spirochetal diseases that can affect the human nervous system. This review presents current concepts of the epidemiology, clinical manifestations, laboratory diagnosis, and management of these disorders, and it provides special emphasis on the management of patients with both HIV infection and neurosyphilis.

Acquired Immunodeficiency Syndrome↗
PubMed1994

A rabbit model of Lyme neuroborreliosis: characterization by PCR, serology, and sequencing of the OspA gene from the brain.

To test whether rabbits can serve as a model for Lyme neuroborreliosis (LNB), we injected New Zealand white rabbits with Borrelia burgdorferi. We obtained samples of blood and CSF for culture, polymerase chain reaction/hybridization (PCR/H), serology, and Western blot. We then sacrificed the rabbits 2 to 3 months after infection and removed organs for culture and PCR/H analysis. The rabbits developed an antibody response, characterized by ELISA and Western blot analysis, consistent with a systemic infection. PCR/H and blood cultures were negative, but PCR/H analysis of CSF in one rabbit was positive. Positive PCR/H analysis of organs from the rabbits was consistent with widespread dissemination of the organism. The most consistently infected organ was the CNS. To determine whether antigenic variation occurred at the genetic level, we compared the sequences of the OspA gene of both the infecting strain and the brain PCR product. The differences between the two were minimal, indicating that variation in the OspA gene did not occur during in vivo infection in the rabbit. Thus, rabbits, after intradermal inoculation with B burgdorferi, develop a chronic systemic infection in which the CNS is a consistent target. These data indicate that rabbits may be an excellent model of LNB.

Animals↗
PubMed1993

The polymerase chain reaction in the diagnosis of Lyme neuroborreliosis.

The polymerase chain reaction is sensitive and specific in the detection of defined DNA sequences and holds promise for diagnosing the presence of fastidious microorganisms in human infectious diseases. We developed a methodology for nested polymerase chain reaction and hybridization analysis of the cerebrospinal fluid using primers from a genomic Borrelia burgdorferi sequence and applied it to the cerebrospinal fluid (CSF) of patients suspected of having Lyme neuroborreliosis and other diseases. Polymerase chain reaction and hybridization demonstrated extremely high sensitivity for spirochetal DNA, and was highly specific, with a false-positivity rate of less than 3%. However, the results were negative or indeterminate in 54% of CSF samples from patients with definite or probable disease, indicating an absence, or extremely low level, of spirochetes or spirochetal DNA in a significant percentage of patients with Lyme neuroborreliosis. Polymerase chain reaction and hybridization of the CSF can thus be considered a useful adjunct in diagnosis, but its negativity does not rule out Lyme neuroborreliosis.

Antibodies, Bacterial↗
PubMed1993

Comparison of polymerase chain reaction with culture and serology for diagnosis of murine experimental Lyme borreliosis.

After the intradermal inoculation of mice with Borrelia burgdorferi, the antibody response, culture, and histology of blood and target organs were assessed and compared with results of a nested polymerase chain reaction (PCR) assay. Of 247 specimens of heart, brain, bladder, and blood, the tested concordance between the PCR and culture was 72%. In the 69 instances of discordance, the PCR was positive in 51 and the culture was positive in 18; thus, the PCR was concordant or more sensitive in 93% of the tested organs. In mice infected with 10 spirochetes, serology confirmed by Western blotting (immunoblotting) was more sensitive than either culture or PCR of brain, bladder, or heart specimens. The organs most commonly culture or PCR positive were the heart and bladder; the brain was infected in only 26% of the animals. DNA hybridization was helpful in confirming the PCR product as being specific and, in some cases, in demonstrating a positive product in the face of negative agarose gels. PCR was less sensitive than culture in detecting the presence of spirochetes in blood specimens, possibly because of the presence of blood inhibitors. We thus found a nested PCR assay, using primers from a genomic sequence, to be a valuable adjunct to serology and culture in the study of murine Lyme borreliosis. The assay confirmed that, after small numbers of spirochetes are injected intradermally, the heart and bladder, and less frequently the brain, are sites of persistence of the spirochetes.

Animals↗
PubMed1992

Western blotting in evaluating Lyme seropositivity and the utility of a gel densitometric approach.

The antibody response to Borrelia burgdorferi is widely used in the diagnosis of Lyme neuroborreliosis and other manifestations of Lyme disease. However, a problem with immunoassays has been a significant number of false positives. The Western blotting technique is a useful adjunct in the serodiagnosis of other infections, but its use in Lyme borreliosis has been limited because of a lack of definition of what constitutes a positive assay. Using a gel densitometric analysis, we devised quantitative criteria for positivity and tested our criteria by matching blot results with clinical characteristics in a retrospectively studied group of 20 patients with Lyme disease, 23 healthy controls, and 18 patients with other neurologic and rheumatologic diseases. We then evaluated these criteria prospectively in serum from 35 ELISA-positive patients, and found that the serum from the majority of patients with positive serologies by ELISA were negative by Western blot. The Western blot-negative seropositive patients usually had other inflammatory or infectious diseases. We conclude that quantitative Western blotting is a helpful test in the serodiagnosis of Lyme neuroborreliosis and other manifestations of Lyme disease.

Blotting, Western↗
PubMed1992

CNS Lyme disease.

Explore the source record for details and available documents.

Borrelia burgdorferi Group↗
PubMed1991

Chronic murine experimental myasthenia gravis: strength testing and serology.

CB6 (Balb/c x C57Bl/6 F1) and C57Bl/6 (B6) mice were hyperimmunized with Torpedo acetylcholine receptor (AChR) for 7 months. Control groups were hyperimmunized with bovine serum albumin. Antibody titers against Torpedo AChR rose quickly, reaching plateau levels by 3-4 months, while antibody to mouse AChR lagged by a few months, reaching plateau levels in 5 months. After the last immunization the mice maintained a state of stable autoimmunity for 9 months with high levels of antibodies against Torpedo and mouse AChR. Fatigability was measured on a programmable treadmill and remained present through the 9 months after the last immunization. CB6 mice had less weakness than the B6 mice, but the latter strain when immunized with BSA had more "false-positive" weakness. Titers of antibodies did not correlate with the degree of weakness measured on the treadmill. Despite the weakness and the high titers of anti-AChR antibodies, sera from myasthenic mice, in contrast to sera from myasthenic humans, were not able to block bungarotoxin binding to native AChR on the surface of BC3H1 cells.

Animals↗
PubMed1991

Anti-ligand antibodies as potential autoantigens: in vitro and in vivo characteristics of anti-bungarotoxin antibodies in the idiotype network.

Some antibodies to ligands of a receptor will have combining sites that structurally resemble the receptor's binding site for that ligand. The network hypothesis predicts that anti-idiotypic antibodies to these anti-ligand antibodies will also bind to the receptor. We pursued these hypotheses in the well-defined ligand-receptor system, alpha-bungarotoxin(BTX)-acetylcholine receptor (AChR). Monoclonal antibodies (mAbs) to BTX were generated; native BTX was used as the immunogen to optimize the probability of obtaining mAbs to the AChR binding site. These mAbs were then characterized for their ability to "mimic" AChR in the following in vitro assays: neutralization of BTX binding to native AChR on the surface of the cell line TE671, formation of a ternary complex with 125BTX-AChR, and ability of cholinergic ligands to interfere with binding to BTX. Three aBTX mAbs which had in vitro attributes of the AChR on the basis of these assays, were injected into C3H mice and serial sera tested for antibodies to Torpedo and murine AChR. Anti-AChR antibodies directed primarily to the gamma and delta subunits of the Torpedo AChR were detected, as well as low amounts of anti-mouse AChR antibody. The generation of anti-AChR antibodies by immunization with aBTX antibodies supports the network hypothesis and provides a theoretical basis for initiation of autoimmunity to cell receptors.

Animals↗
PubMed1990

A sensitive rosetting assay for detection of acetylcholine receptor antibodies using BC3H-1 cells: positive results in 'antibody-negative' myasthenia gravis.

Antibodies to acetylcholine receptor (AChR) were measured in a group of patients with myasthenia gravis (MG), some of whom had previously been classified as 'antibody negative' using the standard anti-AChR radioimmunoassay (RIA). AChR antibodies were measured using the rosetting assay, a new detection method which utilizes protein A-coated red blood cells and live BC3H-1 cells, a murine cell line which expresses muscle nicotinic AChR. The results of the rosetting assay were compared with those obtained in the anti-AChR RIA. 76% of all myasthenic sera tested showed rosetting at titers higher than any of the control sera (from patients with non-myasthenic neurologic disease and normal individuals). Of the myasthenic patients previously classified as 'antibody negative' in the RIA using human AChR, 71% demonstrated positive rosetting. There was no correlation between the anti-AChR antibody titer obtained in the rosetting assay and that obtained in the RIA using either human or denervated rat AChR. The results suggest that the rosetting assay may measure a subpopulation of antibodies that differs from those detected in the RIA.

Animals↗
PubMed1990

Neuro-ophthalmologic manifestations of Lyme disease.

Lyme disease is a tick-borne spirochetal infection characterized by skin rash, neurologic, cardiac, and arthritic findings. The authors report six patients with Lyme disease who had neuro-ophthalmologic manifestations. One patient had meningitis with papilledema, two had optic neuritis, and one had neuroretinitis. Three patients had sixth nerve paresis, two of whom cleared quickly, whereas multiple cranial nerve palsies and subsequent optic neuropathy developed in another. Early recognition of neuro-ophthalmologic findings can help in the diagnosis and treatment of Lyme disease.

Abducens Nerve↗
PubMed1990

Borrelia burgdorferi infection of the brain: characterization of the organism and response to antibiotics and immune sera in the mouse model.

To learn more about the neurologic involvement in Lyme disease, we inoculated inbred mice with the causative agent of Lyme disease, Borrelia burgdorferi. We cultured brains and other organs, and measured anti-B burgdorferi antibody titers. We further studied a brain isolate for its plasmid DNA content and its response in vitro to immune sera and antibiotics. One strain of B burgdorferi, N40, was consistently infective for mice, and resulted in chronic infection of the bladder and spleen. SJL mice developed fewer culture-positive organs and had lower antibody titers than Balb/c and C57Bl/6 mice. Organism was cultured from the brain early in the course of infection, and this isolate, named N40Br, was further studied in vitro. The plasmid content of N40Br was different from that of the infecting strain, implying either a highly selective process during infection or DNA rearrangement in the organism in vivo. N40Br was very sensitive to antibiotics, but only after prolonged incubation. Immune sera from both mice and humans infected with B burgdorferi were unable to completely kill the organism by complement-mediated cytotoxicity. These data demonstrate that B burgdorferi infects the brain of experimental animals, and is resistant to immune sera in vitro but sensitive to prolonged treatment with antibiotics.

Animals↗