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Biomedical subjects

N Page

Publications and source records attributed to N Page.

At least 19 recordsLinked to original sources
PubMed1991

Detection of foreign DNA in transgenic chicken embryos using the polymerase chain reaction.

Chicken primordial germ cells were infected with a defective retrovirus containing the Escherichia coli lacZ gene and injected into the heart of stage 15 embryos. DNA samples were isolated from various tissues of the injected embryos at different stages of development and were examined for the presence of the lacZ gene using the polymerase chain reaction. Integration of the retrovirus DNA was demonstrated with a 32P-labelled oligonucleotide in five-, 10- and 18-day embryos. This quick procedure provides an opportunity for the early detection of foreign DNA in small numbers of transfected cells and is a valuable tool in the detection of transgenic animals.

Animals↗
PubMed1989

A syngeneic monoclonal anti-idiotype antibody against HNK-1: characterization and cytotoxic activity in vitro.

A syngeneic, monoclonal, anti-idiotype antibody, G6D9, was raised against the mouse monoclonal IgM HNK-1. G6D9, characterized as an IgG1-kappa, inhibits the binding of HNK-1 to the myelin-associated glycoprotein (MAG). G6D9 does not interfere with the binding of various human monoclonal anti-MAG IgM to their specific antigen. G6D9 binds HNK-1 hybridoma cells on their surface and within their cytoplasm, as demonstrated using indirect immunofluorescence. In the presence of complement, G6D9 is cytotoxic for HNK-1-secreting cells. A cell lysis of 32% was observed and compared to lysis obtained with other antibodies directed against mouse lymphocyte antigens. The use of G6D9 as a tool to study specific cytotoxicity and immunotherapy in vivo is discussed.

Animals↗
PubMed1987

Surgical treatment of syringomyelia with syringopleural shunting.

The clinical course of 21 patients who underwent syringopleural shunting for syringomyelia is summarised. All the patients were continuing to deteriorate at the time of the operation. Objective improvement was seen in nine patients following the procedure but three subsequently deteriorated. Contralateral syrinx symptoms have appeared in two patients. No change was seen in six patients who did not deteriorate later. Three were worse following the procedure. In syringomyelia with marked hydrocephalus, ventricular drainage by a valved shunt may be the preferred first procedure. Craniovertebral decompression is recommended for syringomyelia with hindbrain herniation without dense arachnoiditis. In appropriate cases syringopleural shunting may be performed in combination with craniovertebral decompression, and may be the procedure of choice in cases with marked hindbrain arachnoiditis. In cases with a sizeable syrinx who have subsequently deteriorated following craniovertebral decompression, syringopleural shunting may be considered the preferred second procedure. Syringopleural shunting is suggested in amenable cases of syringomyelia associated with spinal tumour, trauma or arachnoiditis.

Adult↗
PubMed1986

Analysis of downbeat nystagmus. Otolithic vs semicircular canal influences.

The relative strengths of vertical canal and otolithic factors influencing downbeat nystagmus (DBN) were investigated in a patient whose nystagmus was of maximum intensity with the head in the upright position and abolished with the head in the supine position. The vestibuloocular reflex (VOR) was assessed by oscillating the patient about both the supine and upright positions. During oscillation about the supine position both the upward and downward VORs had equal gains in the dark (0.6) and unity gain in the light. In contrast, during oscillation about the upright, the upward VOR became hyperactive with a gain of 1.8 in the dark and 1.2 in the light, whereas the downward VOR became hypoactive with a maximum gain of 0.86 in the light. This degree of asymmetry of the VOR is greater than would be expected from a summation of spontaneous nystagmus with normal canal reflexes. We concluded that the DBN arose from an asymmetry of vertical canal function, which became manifest when the otoliths were tilted with respect to gravity. Contrasting findings are presented in a patient whose DBN was insensitive to tilt. It would seem that other cases of DBN lie on a continuum between these extreme examples.

Adult↗
PubMed1986

The human anti-myelin-associated glycoprotein IgM system.

Two mouse monoclonal antiidiotypic antibodies that react with human monoclonal IgM antibodies with specificity for myelin-associated glycoprotein (MAG) have been used to study the immunological specificity of the reported cross-reactions involving the anti-MAG IgM. Both of the antiidiotypic antibodies are shown to react with the combining site of their respective idiotypic IgM and to inhibit the reaction between IgM and MAG. Using these antiidiotypic antibodies as "surrogate" antigen, we have demonstrated immune cross-reactivity between MAG, a human peripheral nerve glycolipid, and a low-molecular-weight protein of human peripheral nerve myelin. In addition, we have used the two antiidiotypic antibodies to conduct a search for evidence of shared idiotypy among 34 different neuropathy-associated paraproteins. Our results provide no evidence for a neuropathy-associated idiotype, suggesting a degree of polymorphism in the human anti-MAG IgM system.

Animals↗
PubMed1985

A monoclonal anti-idiotypic antibody against a human monoclonal IgM with specificity for myelin-associated glycoprotein.

A human monoclonal IgM lambda antibody, directed against MAG, obtained from a patient with polyneuropathy associated with a gammopathy, was used as an immunogen to generate mouse monoclonal anti-idiotype antibodies. One hybridoma antibody, designated A8F2, reacts uniquely with the M-IgM of the patient, shows high affinity binding to the patient's M-IgM, and dose-dependently inhibits binding of the patient's M-IgM to its specific antigen MAG. Thus, A8F2 is a monoclonal anti-idiotype antibody that recognizes a region of the MAG binding site of the patient's IgM. Use of this anti-idiotype antibody in a competition RIA revealed the presence of naturally occurring anti-idiotype in the patient's serum. Because anti-idiotype antibodies may be part of a mechanism for down-regulation of antibody production, the use of A8F2 to induce a specific immunosuppression should be considered.

Animals↗
PubMed1984

Human monoclonal antibodies to myelin-associated glycoprotein are directed against the polypeptide and not the carbohydrate moiety.

We have used an approach which combines the technique of electrophoretic blotting of polyacrylamide gels with methods for the degradation of carbohydrates, to study the myelin-associated glycoprotein (MAG)-specific antibodies found in 5 patients with demyelinating neuropathy. Our results show that it is possible to deglycosylate proteins on nitrocellulose blots and then to examine their antigenicity and lectin-binding properties. With MAG, our findings suggest that the monoclonal IgM antibodies from all the patients studied have specificity for the polypeptide and not the carbohydrate moiety.

Antibodies, Anti-Idiotypic↗
PubMed1984

The differential diagnosis of congenital nystagmus.

The decision whether a nystagmus is congenital or acquired may be difficult and is of importance in patients presenting with neurological complaints. In this article, established diagnostic criteria are critically reviewed with particular emphasis on types of nystagmus waveform and their relationship to pursuit and optokinetic responses. Attention is drawn to certain acquired nystagmus which may have similar features which have hitherto been accepted as pathognomonic of congenital nystagmus. Symptoms due to congenital nystagmus are discussed and related to the oculomotor abnormalities. The importance of the characteristics of congenital nystagmus are evaluated for use in differential diagnosis.

Diagnosis, Differential↗
PubMed1983

Binding properties of cerebrospinal fluid IgG in multiple sclerosis and other neurological diseases.

A solid phase radioimmunoassay (RIA) was used to detect antibodies to myelin or myelin basic protein (MBP) in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) or other neurological diseases (OND). When measured at the same IgG concentration, MS samples had higher binding values than OND against myelin, but not against MBP. Using F(ab')2 fragments purified from pools of MS and OND CSF there was no difference in binding to myelin between MS and OND samples. These results indicate that anti-MBP antibodies are nt a feature of MS and binding of CSF IgG to myelin is not due to specific antibody, but is probably the result of non-specific binding to Fc receptors.

Humans↗
PubMed1983

Demyelinating neuropathy and monoclonal IgM antibody to myelin-associated glycoprotein.

We studied a patient with demyelinating neuropathy and monoclonal IgM kappa antibody to the major myelin-associated glycoprotein (MAG). Binding of this monoclonal antibody to the myelin antigen was demonstrated by immunoelectroblot. Binding to MAG seemed to be specific, because it was completely inhibited by MAG isolated from human myelin. Immunostaining was observed with MAG from CNS and peripheral nervous system myelin.

Antibodies, Monoclonal↗
PubMed1982

The effect of specific antibody on antibody-independent interactions between E. coli J5 and human complement.

We previously reported that Escherichia coli J5, the galactose epimerase-deficient mutant of E. coli O111:B4, can bind and activate purified human C1. The effects of hyperimmune rabbit anti-J5 IgG or IgM on E. coli J5 interactions with human C have been examined. Specific IgG or IgM increased the binding of 125I-C1 by J5. However, the rate of C1 activation, as determined by SDS-PAGE of eluted 125I-C1s, was decreased if bacteria were preincubated with immune IgG. Complexes formed between J5 preincubated with immune Ig and C1, under conditions in which all of the C1 was allowed to activate, consumed more C4 than J5 alone plus C1. However, the amount of C4 consumed per C1 molecule was identical for all bacteria preparations. Concentrations of specific IgG or IgM that significantly increased C1 binding did not appear to enhance C3b deposition upon incubation of E. coli J5 in NHS. Thus, although specific antibody may enhance C1 binding by E. coli J5, the ability of these additional C1 molecules to alter later events in the C cascade may depend on the control of C1 activation and its subsequent activity when bound to different membrane components.

Animals↗