Biomedical subjects

B C Jacobs

Publications and source records attributed to B C Jacobs.

At least 19 recordsLinked to original sources

PubMed2002

High-fidelity quantum logic operations using linear optical elements.

Knill, Laflamme, and Milburn [Nature (London) 409, 46 ((2001))]] have shown that quantum logic operations can be performed using linear optical elements and additional ancilla photons. Their approach is probabilistic in the sense that the logic devices fail to produce an output with a failure rate that scales as 1/n, where n is the number of ancilla. Here we present an alternative approach in which the logic devices always produce an output with an intrinsic error rate that scales as 1/n(2), which may have several advantages in quantum computing applications.

Journal Article↗

PubMed2002

Demonstration of nondeterministic quantum logic operations using linear optical elements.

Knill, Laflamme, and Milburn [Nature (London) 409, 46 (2001)] recently showed that nondeterministic quantum logic operations could be performed using linear optical elements, additional photons (ancilla), and postselection based on the output of single-photon detectors. Here we report the experimental demonstration of two logic devices of this kind, a destructive controlled-NOT (CNOT) gate and a quantum parity check. These two devices can be combined with a pair of entangled photons to implement a conventional (nondestructive) CNOT that succeeds with a probability of 1/4.

Journal Article↗

PubMed2002

Cross-reactive anti-galactocerebroside antibodies and Mycoplasma pneumoniae infections in Guillain-Barré syndrome.

Anti-galactocerebroside (GalC) antibodies are reported to be present in GBS patients with preceding Mycoplasma pneumoniae (MP) infection. We investigated the presence of anti-GalC reactivity in serum of a large group of GBS patients using ELISA and compared this with healthy controls and individuals with an uncomplicated MP infection. Anti-GalC antibody reactivity was present in 12% of the GBS patients. Furthermore, anti-GalC antibodies were associated with MP infections, a relatively mild form of the disease and demyelinating features. Anti-GalC antibodies cross-reacted with MP antigen. In conclusion, anti-GalC antibodies in GBS patients may be induced by molecular mimicry with MP.

Autoantibodies↗

PubMed2002

Structure of Campylobacter jejuni lipopolysaccharides determines antiganglioside specificity and clinical features of Guillain-Barré and Miller Fisher patients.

Ganglioside mimicry in the lipopolysaccharide (LPS) fraction of Campylobacter jejuni isolated from Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS) patients was compared with isolates from patients with an uncomplicated enteritis. The antibody response to C. jejuni LPS and gangliosides in neuropathy patients and controls was compared as well. LPS from GBS and MFS-associated isolates more frequently contained ganglioside-like epitopes compared to control isolates. Almost all neuropathy patients showed a strong antibody response against LPS and multiple gangliosides in contrast to enteritis patients. Isolates from GBS patients more frequently had a GM1-like epitope than isolates from MFS patients. GQ1b-like epitopes were present in all MFS-associated isolates and was associated with anti-GQ1b antibody reactivity and the presence of oculomotor symptoms. These results demonstrate that the expression of ganglioside mimics is a risk factor for the development of post-Campylobacter neuropathy. This study provides additional evidence for the hypothesis that the LPS fraction determines the antiganglioside specificity and clinical features in post-Campylobacter neuropathy patients.

Antibodies, Bacterial↗

PubMed2001

Differential immune response to gangliosides in Guillain-Barré syndrome patients from Japan and The Netherlands.

Anti-ganglioside antibodies are consistently found in Guillain-Barré syndrome (GBS) patients from different geographical parts of the world. Several studies indicated differences in relative frequencies of anti-ganglioside reactivity and isotype distribution between GBS patients from Asia and from Europe. We investigated antibody reactivity against the gangliosides GM1, GM1b and GalNAc-GD1a in GBS patients from Japan and The Netherlands in two different laboratories. The proportion of GBS patients with anti-ganglioside antibodies did not differ between the two countries. GBS patients from The Netherlands more frequently had cross-reacting anti-GalNAc-GD1a/anti-GM1b antibodies and a stronger IgM anti-ganglioside response. Our findings indicate that geographical determined factors, dependent on either the host or the triggering infectious agent, determine the isotype distribution and fine specificity of anti-ganglioside antibodies in GBS patients.

Adolescent↗

PubMed2001

Antiganglioside antibodies in polyneuropathy associated with monoclonal gammopathy.

Antibody reactivity to GA1, GM1, GM2, GD1a, GD1b, and GQ1b gangliosides was measured in 87 patients with polyneuropathy associated with monoclonal gammopathy (60 IgM, 25 IgG, 2 IgA) and 42 control patients with monoclonal gammopathy without polyneuropathy (21 IgM, 21 IgG). Of these 87 patients, 30% had anti-myelin-associated glycoprotein antibodies and 15% had antiganglioside antibodies. Antiganglioside antibodies were significantly associated with demyelinating neuropathy and with IgM monoclonal gammopathy. Anti-GD1b and anti-GQ1b antibodies were significantly associated with predominantly sensory ataxic neuropathy.

Adult↗

PubMed2001

Gastroenteritis-associated Guillain-Barré syndrome on the Caribbean island Curaçao.

BACKGROUND: The number of patients with Guillain-Barré syndrome (GBS) who have been observed in Curaçao, the Netherlands Antilles, may be increasing. METHODS: Clinical and serologic data were obtained from records of patients admitted between 1987 and 1999 and fulfilling National Institute of Neurological and Communicative Disorders and Stroke criteria for GBS. When possible, serum and stool samples were collected. The results were compared with a large Dutch epidemiologic study. RESULTS: The authors identified 49 patients, an overall crude incidence rate (IR) in Curaçao of 2.53/100,000 inhabitants (95% CI 1.87 to 3.35) (Dutch study 1.18, rate ratio (RR) of 2.14, p < 0.001). The IR in Curaçao increased from 1.62 in 1987 to 1991 to 3.10 in 1992 to 1999, RR 5.22 (95% CI 2.48 to 10.2, p = 0.02). The IR showed a curvilinear shape within a year. In comparison with the Dutch group, patients from Curaçao had a more severe course of the disease, with a mortality rate of 23% (3.4% in the Dutch group, p < 0.001), a higher percentage of preceding gastroenteritis (p < 0.001), and less sensory involvement (p < 0.001). In 8 of 10 serum samples, evidence was found for a recent infection with Campylobacter jejuni. CONCLUSIONS: The authors found a steady increase in incidence of GBS over the years in association with a more pronounced seasonal preponderance and a more severe course. The clinical characteristics suggest a role for C jejuni.

Campylobacter Infections↗

PubMed2001

Guillain-Barré syndrome- and Miller Fisher syndrome-associated Campylobacter jejuni lipopolysaccharides induce anti-GM1 and anti-GQ1b Antibodies in rabbits.

Campylobacter jejuni infections are thought to induce antiganglioside antibodies in patients with Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS) by molecular mimicry between C. jejuni lipopolysaccharides (LPS) and gangliosides. We used purified LPS fractions from five Campylobacter strains to induce antiganglioside responses in rabbits. The animals that received injections with LPS from GBS-associated strains developed anti-GM1 and anti-GA1 antibodies. Animals injected with LPS from one MFS-related C. jejuni strain produced anti-GQ1b antibodies. Rabbits that were injected with Penner O:3 LPS had a strong anti-LPS response, but no antiganglioside reactivity was observed. The antiganglioside specificity in the rabbits reflected the specificity in the patients from whom the strains were isolated. In conclusion, our results indicate that an immune response against GBS- and MFS-associated C. jejuni LPS results in antiganglioside antibodies. These results provide strong support for molecular mimicry as a mechanism in the induction of antiganglioside antibodies following infections.

Adult↗

PubMed2001

Comparative study of preceding Campylobacter jejuni infection in Guillain-Barré syndrome in Japan and The Netherlands.

A comparative study was made in Japan and The Netherlands of the presence of preceding Campylobacter jejuni infections in Guillain-Barré syndrome (GBS). It was conducted in two laboratories using different serological criteria. The Japanese results showed no significant difference in the frequency of C jejuni infection between the Japanese (17/88, 19%) and Dutch (21/132, 16%) patients with GBS. The Dutch investigation showed a higher frequency in Dutch patients (45/132; 34%) than in Japanese patients(20/88; 23%), but the difference did not reach significance. Although the frequencies of preceding C jejuni infection have been reported to be higher in Asian countries than in western countries, the findings of this collaborative study show that the incidence of antecedent C jejuni infection in GBS in Japan is not higher than in The Netherlands and that serological assays vary considerably between laboratories.

Campylobacter Infections↗

PubMed2000

A case of Guillain-Barré syndrome following a family outbreak of Campylobacter jejuni enteritis.

We describe an outbreak of Campylobacter jejuni enteritis involving three family members of whom one developed Guillain-Barré syndrome (GBS). The patients' serum reacted strongly with several gangliosides and with the lipopolysaccharide (LPS) fractions from the C. jejuni strains isolated from his family members. Only low titer anti-ganglioside antibodies were found in his siblings. HLA-typing did not indicate a locus associated with auto-antibody production. Comparing the immune response in GBS patients and C. jejuni enteritis patients can be of great value in determining the additional factors that lead to post-Campylobacter GBS. Ganglioside mimicry alone is necessary but not sufficient for the induction of anti-ganglioside antibodies. Other susceptibility factors are required to induce an anti-neural immune response.

Adult↗

PubMed2000

Campylobacter jejuni lipopolysaccharides from Guillain-Barré syndrome patients induce IgG anti-GM1 antibodies in rabbits.

Lipopolysaccharides (LPS) from Campylobacter jejuni strains isolated from patients with Guillain-Barré syndrome (GBS) display molecular mimicry with GM1. We immunized rabbits with C. jejuni LPS from GBS-associated strains containing a GM1-like epitope. All animals produced high titre anti-LPS antibodies that were cross-reactive with GM1. We conclude that C. jejuni strains from GBS patients are able to induce antibodies that cross-react with gangliosides and LPS. This study further confirms the role of molecular mimicry in the induction of anti-ganglioside antibodies in GBS patients.

Animals↗

PubMed2000

Cross-reactive antibodies against GM2 and CMV-infected fibroblasts in Guillain-Barré syndrome.

OBJECTIVE: To investigate whether anti-GM2 antibodies in patients with Guillain-Barré syndrome (GBS) are induced by molecular mimicry with cytomegalovirus (CMV). BACKGROUND: Antibodies against ganglioside GM2 are frequently present in the serum from GBS patients with an antecedent infection with CMV. METHODS: The authors detected inhibition of anti-GM2 reactivity after incubation of GM2-reactive serum samples with fibroblasts infected with a GBS-associated CMV strain. Control sera consisted of GQ1b-reactive samples, and control antigens included uninfected fibroblasts and fibroblasts that were infected with other herpes viruses. RESULTS: Serum immunoglobulin M reactivity with GM2 was decreased in a dose-dependent manner after incubation with CMV-infected fibroblasts. Incubation of anti-GM2-positive serum samples with uninfected fibroblasts and fibroblasts infected with varicella zoster virus did not inhibit anti-GM2 reactivity, whereas this reactivity was slightly decreased after incubation with herpes simplex virus type 1 in one patient. Antibodies against ganglioside GQ1b did not react with CMV-infected fibroblasts. CONCLUSIONS: CMV-infected fibroblasts express gangliosidelike epitopes that recognize specifically anti-GM2 antibodies. These results support the hypothesis that antiganglioside antibodies in CMV-infected GBS patients are induced by molecular mimicry between GM2 and antigens that are induced by a CMV infection.

Adult↗

PubMed2000

Evaluation of a new commercial immunoassay for rapid detection of Campylobacter jejuni in stool samples.

In order to evaluate a new commercial enzyme immunoassay (ProspecT Campylobacter Microplate Assay; Alexon-Trend, USA) for the detection of Campylobacter jejuni and Campylobacter coli in stool samples, 30 faecal specimens known to be culture-positive for Campylobacter jejuni were tested with the new assay. The detection limit was approximately 3 x 10(6)/ml in faecal suspensions. The sensitivity relative to culture was 80% (24/30). All of the 24 positive samples, except for one, remained positive after being stored at -20 degrees C for 60 days. The specificity of the test was 100%. Interestingly, 6 of 11 additional Campylobacter jejuni culture-positive samples that had been obtained from patients with Guillain-Barré syndrome and stored at -20 degrees C for periods of up to 5 years tested positive in the assay. The performance of the assay indicates that it has potential value for use in future early intervention studies.

Campylobacter Infections↗

PubMed2000

Molecular characterization of Campylobacter jejuni from patients with Guillain-Barré and Miller Fisher syndromes.

Campylobacter jejuni has been identified as the predominant cause of antecedent infection in Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS). The risk of developing GBS or MFS may be higher after infection with specific C. jejuni types. To investigate the putative clonality, 18 GBS- or MFS-related C. jejuni strains from The Netherlands and Belgium and 17 control strains were analyzed by serotyping (Penner and Lior), restriction fragment length polymorphism analysis of PCR products of the flaA gene, amplified fragment length polymorphism analysis, pulsed-field gel electrophoresis, and randomly amplified polymorphic DNA analysis. Serotyping revealed 10 different O serotypes and 7 different Lior serotypes, thereby indicating a lack of serotype clustering. Two new O serotypes, O:35 and O:13/65, not previously associated with GBS or MFS were found. Serotype O:19 was encountered in 2 of 18 strains, and none was of serotype O:41. The results of all genotypic methods also demonstrated substantial heterogeneity. No clustering of GBS- or MFS-related strains occurred and no molecular marker capable of separating pathogenic GBS or MFS from non-GBS- or non-MFS-related enteritis strains could be identified in this study. Sialic-acid-containing lipopolysaccharides (LPS) are thought to be involved in the triggering of GBS or MFS through molecular mimicry with gangliosides in human peripheral nerves. Therefore, further characterization of GBS- or MFS-related C. jejuni should target the genes involved in the synthesis of LPS and the incorporation of sialic acid.

Bacterial Typing Techniques↗

PubMed2000

Clinical features and response to treatment in Guillain-Barré syndrome associated with antibodies to GM1b ganglioside.

GM1b is a minor ganglioside in human peripheral nerves. Serum anti-GM1b antibodies frequently are present in patients with Guillain-Barré syndrome (GBS). In this collaborative study, we investigated the antecedent infections, clinical features, and response to treatment of GBS patients with anti-GM1b antibodies. Of 132 GBS patients who participated in the Dutch GBS trial that compared the effect of intravenous immunoglobulins and plasma exchange, 25 (19%) patients had anti-GM1b antibodies. IgM antibodies were present in 14, IgG antibodies in 15, and both isotypes in 4 patients. The 25 patients with anti-GM1b antibodies had a clinical pattern distinct from that of the other 107 GBS patients. They more often had an episode of gastrointestinal illness and frequently showed serological evidence of recent infection by Campylobacter jejuni. The anti-GM1b-positive subgroup was marked by more rapidly progressive, more severe, and predominantly distal weakness. Cranial nerve involvement and sensory deficits were less common in the patients with anti-GM1b antibodies. The presence of anti-GM1b antibodies was associated with slower recovery. The clinical manifestations predominantly were associated with anti-GM1b antibodies of the IgG isotype. Fourteen (56%) of the 25 patients with anti-GM1b antibodies also had anti-GM1 antibodies. The group of patients with both antibodies was clinically more homogeneous and had a more rapidly progressive, pure motor neuropathy. The subgroup of anti-GM1b-positive GBS patients responded well to treatment with immunoglobulins but not to plasmapheresis. The distinctive clinical features of the patients with anti-GM1b antibodies show that acute motor neuropathy represents a specific subgroup within GBS and that recognizing these patients may have consequences as to the choice of therapy.

Adolescent↗

PubMed1999

Rapidly progressive, predominantly motor Guillain-Barré syndrome with anti-GalNAc-GD1a antibodies.

OBJECTIVE: To investigate the presence of anti-GalNAc-GD1a antibodies in patients with Guillain-Barré syndrome (GBS) and to determine the relation of anti-ganglioside antibodies with clinical features. BACKGROUND: The GBS is heterogeneous with regard to clinical manifestations, antecedent infections, and the presence and specificity of anti-ganglioside antibodies. Recently, antibodies to minor gangliosides have been identified in serum from GBS patients. METHODS: The authors used ELISA to detect anti-ganglioside antibodies in 132 GBS patients and then correlated results with a database containing information on antecedent infections and clinical parameters. RESULTS: Anti-GalNAc-GD1a antibodies could be detected in 19 (14%) GBS patients. The presence of anti-GalNAc-GD1a antibodies was related to antecedent Campylobacter jejuni infection (p<0.001). GBS patients with anti-GalNAc-GD1a antibodies had a rapidly progressive, more severe, and predominantly distal weakness. Furthermore, they had less sensory loss, paresthesia, and cranial nerve involvement. In most patients, this reactivity was independent of reactivity to GM1. Dividing patients into separate groups based on their reactivity to GalNAc-GD1a and GM1 enabled the authors to delineate more homogeneous subgroups with regard to clinical features. CONCLUSIONS: This study provides further evidence for the hypothesis that antecedent infections and the specificity of subsequent anti-neural antibody responses determine the clinical manifestations in GBS patients.

Adolescent↗

PubMed1999

Miller Fisher anti-GQ1b antibodies: alpha-latrotoxin-like effects on motor end plates.

In the Miller Fisher syndrome (MFS) variant of the Guillain-Barré syndrome, weakness is restricted to extraocular muscles and occasionally other craniobulbar muscles. Most MFS patients have serum antibodies against ganglioside type GQ1b of which the pathophysiological relevance is unclear. We examined the in vitro effects of MFS sera, MFS IgG, and a human monoclonal anti-GQ1b IgM antibody on mouse neuromuscular junctions (NMJs). It was found that anti-GQ1b antibodies bind at NMJs where they induce massive quantal release of acetylcholine from nerve terminals and eventually block neuromuscular transmission. This effect closely resembled the effect of the paralytic neurotoxin alpha-latrotoxin at the mouse NMJs, implying possible involvement of alpha-latrotoxin receptors or associated downstream pathways. By using complement-deficient sera, the effect of anti-GQ1b antibodies on NMJs was shown to be entirely dependent on activation of complement components. However, neither classical pathway activation nor the formation of membrane attack complex was required, indicating the effects could be due to involvement of the alternative pathway and intermediate complement cascade products. Our findings strongly suggest that anti-GQ1b antibodies in conjunction with activated complement components are the principal pathophysiological mediators of motor symptoms in MFS and that the NMJ is an important site of their action.

Animals↗

PubMed1998

Differences in N-acetylmuramyl-L-alanine amidase and lysozyme in serum and cerebrospinal fluid of patients with bacterial meningitis.

N-acetylmuramyl-L-alanine amidase (NAMLAA) specifically degrades peptidoglycan, a major component of bacterial cell walls. Lysozyme degrades peptidoglycan differently by hydrolyzing the aminosugar backbone of peptidoglycan. In another study, it was shown that the two enzymes act synergistically to inactivate the inflammatory properties of peptidoglycan. The presence of lysozyme and NAMLAA was determined in serum and cerebrospinal fluid (CSF) of patients with bacterial meningitis. High concentrations of lysozyme were found in CSF while, surprisingly, NAMLAA was not present. To explain this phenomenon, the degranulation pattern of neutrophils in CSF was compared with that of neutrophils from blood. Specific granules contain lysozyme and the azurophil granules contain both lysozyme and NAMLAA. CD66b expression on the cell surface, indicative for fusion of the specific granules with the cell membrane, was higher in CSF than in blood, while the marker for the azurophil granules was lower.

Adolescent↗