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Biomedical subjects

C I Smith

Publications and source records attributed to C I Smith.

At least 127 records · Page 7Linked to original sources
PubMed1994

Basic fibroblast growth factor increases retroviral-mediated gene transfer into human hematopoietic peripheral blood progenitor cells.

Retroviral vector-mediated gene transfer into human hematopoietic stem cells (HSC) may permit gene therapy of certain genetic diseases. Stimulation of HSC with hematopoietic growth factors (GF) has been shown to increase the level of retroviral transduction. We have studied the effect of basic fibroblast growth factor (bFGF), alone and in combination with other GFs, on the efficiency of transfer of the bacterial neomycin phosphotransferase (neoR) gene into human CD34(+)-enriched peripheral blood hematopoietic progenitor cells. The combination of bFGF, interleukin-3 (IL-3), IL-6, and stem cell factor (SCF) resulted in a transduction efficiency of 37 and 35% for G418-resistant colony-forming units-granulocyte/macrophage (CFU-GM) and mixed colonies multipotent colony-forming units (CFU-GEMM), respectively, which was significantly higher than the corresponding figures obtained with IL-3, IL-6, and SCF. The optimal concentration of bFGF was between 20 and 200 ng/mL. bFGF alone had no effect on the transduction rate. These results indicated a synergism in the action of bFGF, IL-3, IL-6, and SCF to enhance gene transduction rates into human hematopoietic progenitor cells.

Antigens, CD↗
PubMed1994

BMX, a novel nonreceptor tyrosine kinase gene of the BTK/ITK/TEC/TXK family located in chromosome Xp22.2.

The Bmx sequence was identified and cloned during our search for novel tyrosine kinase genes expressed in human bone marrow cells. Bmx cDNA comprises a long open reading frame of 675 amino acids, containing one SH3, one SH2 and one tyrosine kinase domain, which are about 70% identical with Btk, Itk and Tec and somewhat less with Txk tyrosine kinase sequences. The amino terminal sequences of these four tyrosine kinases are about 40% identical and each contains a so-called pleckstrin homology domain. The 2.7 kb Bmx mRNA was expressed in endothelial cells and several human tissues by Northern blotting and an 80 kD Bmx polypeptide was detected in human endothelial cells. Immunoprecipitates of COS cells transfected with a Bmx expression vector and NIH3T3 cells expressing a Bmx retrovirus contained a tyrosyl phosphorylated Bmx polypeptide of similar molecular weight. The BMX gene was located in chromosomal band Xp22.2 between the DXS197 and DXS207 loci. Interestingly, chromosome X also contains the closest relative of BMX, the BTK gene, implicated in X-linked agammaglobulinemia. The BMX gene thus encodes a novel nonreceptor tyrosine kinase, which may play a role in the growth and differentiation of hematopoietic cells.

3T3 Cells↗
PubMed1994

Salivary and serum immunoglobulins in recipients of transplanted allogeneic and autologous bone marrow.

Significantly decreased levels of all classes Ig were found in saliva and serum of 85 patients before and up to 5 years after bone marrow transplantation (BMT). Salivary levels of IgG were increased before BMT in patients that died shortly after transplantation (p = 0.04). Significantly higher secretory IgA (sIgA) levels in saliva were noted in patients with malignant disorders than in those with non-malignant diseases, both before (p = 0.007) and after BMT (p = 0.011). Recipients of autologous marrow had higher levels of salivary sIgA before BMT than recipients of allogeneic bone marrow (p = 0.020). With increased BM cell dose at transplantation, lower levels of salivary IgG and albumin were found. Patients with cytomegalovirus infections after transplantation showed increased salivary IgG levels (p = 0.029). Individuals with chronic GVHD had less salivary IgM one year after BMT (median value 3.2 mg/l, p = 0.04) than those without chronic GVHD (median value 42.6 mg/l). All Ig classes in serum were decreased directly after BMT and later normalized. Salivary levels of all Ig classes except IgD fluctuated post-BMT.

Adolescent↗
PubMed1993

Gamma-globulin modulates growth of EBV-derived B-cell tumors in SCID mice reconstituted with human lymphocytes.

The effect of weekly gamma-globulin injection on the development of human B-cell tumors was studied in 120 mice with severe combined immunodeficiency (SCID). The mice were injected intraperitoneally (i.p.) with human peripheral mononuclear cells (PBMC) from 6 different Epstein-Barr virus (EBV)-seropositive donors. Animals repopulated with cells from 5 donors received gamma-globulin or saline for 20 weeks and were followed up to 24 weeks after reconstitution. A delay in the appearance of fata EBV-derived human B-cell tumors was noticed in the gamma-globulin-treated groups as compared to the controls. In a separate experiment, the effect of gamma-globulin treatment during the initial 4 weeks after reconstitution was compared to treatment from week 5 to week 8 as well as to a continuous 20-week treatment. The results from this experiment showed that B-cell tumor growth could be prevented just as efficiently when the animals were treated only during the first 4 weeks. In contrast, no preventive effect was seen when the first gamma-globulin dose was given at the beginning of week 5 after reconstitution. Our results indicate that gamma-globulin reduces the frequency of EBV-derived B-cell tumor development and suggest that SCID mice repopulated with human cells represent a useful in vivo model for evaluation of the prophylactic and/or therapeutic effects of immunomodulatory treatments in lympho-proliferative disorders associated with immunosuppression.

Animals↗
PubMed1993

Colocalization of X-linked agammaglobulinemia and X-linked immunodeficiency genes.

Mice that bear the X-linked immunodeficiency (xid) mutation have a B lymphocyte-specific defect resulting in an inability to make antibody responses to polysaccharide antigens. A backcross of 1114 progeny revealed the colocalization of xid with Bruton's agammaglobulinemia tyrosine kinase (btk) gene, which is implicated in the human immune deficiency, X-linked agammaglobulinemia. Mice that carry xid have a missense mutation that alters a highly conserved arginine near the amino-terminus of the btk protein, Btk. Because this region of Btk lies outside any obvious kinase domain, the xid mutation may define another aspect of tyrosine kinase function.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed1993

Molecular basis for human immunodeficiencies.

Major emphasis is currently being placed on unraveling the molecular basis of various forms of primary human immunodeficiencies. It is clear from recent studies that not only can different mutations give rise to different phenotypes but the same mutation may result in quite diverse clinical pictures. A correct diagnosis at the DNA level therefore becomes increasingly important in view of the possibility of gene therapy.

Agammaglobulinemia↗
PubMed1993

The life situations of patients with primary antibody deficiency untreated or treated with subcutaneous gammaglobulin infusions.

The life situations of 25 patients with hypogammaglobulinaemia were studied before and after the initiation of subcutaneous replacement therapy by using medical records, data registers and questionnaires (a study and a disease-specific questionnaire, the Sickness Impact Profile and the General Health Rating Index). Before treatment, the patients perceived more dysfunctions with regard to ambulation, mobility, emotional behaviour, social interaction, sleep and rest, household management, work and recreation or pastime activities compared with a Swedish reference group (P = 0.0001). A significant increase in the perceived frequency of infections was also seen in untreated patients compared with a group of healthy individuals (P = 0.0001). After 18 months of weekly subcutaneous infusions of an intramuscular gammaglobulin preparation (100 mg/kg), the patients reported a significantly increased, health-related function and improved self-rated health. A significantly higher pre-infusion IgG level was also found.

Adult↗
PubMed1993

Systemic immunization against IgA in immunoglobulin deficiency.

The presence of serum IgM and IgG antibodies against IgA is common among individuals with IgA deficiency. The route of immunization is still unknown, but it is possible that immunization occurs through the gut. We analysed anti-IgA antibody production in gastrointestinal lavage, saliva and breast milk from patients with IgA deficiency. In no case was there any evidence of local production of anti-IgA antibodies. Immunization may thus be due to exposure to endogenous IgA and therefore represent a 'true' autoimmune phenomenon which may possibly be involved in the pathogenesis of the disease.

Antibodies, Anti-Idiotypic↗
PubMed1993

Novel human immunoglobulin heavy chain constant region gene deletion haplotypes characterized by pulsed-field electrophoresis.

Fifteen patients with selective IgG1 deficiency were screened for immunoglobulin H chain C region locus (IGHC) gene deletions and three deletion haplotypes were found: del G1, del G1-G4 and del G4. These haplotypes, together with four deletion haplotypes described by us previously (del G1 (NY), del G1 (VIT) del G1-G2 (NY) and del G2-G4 (HJE)), were further characterized using pulsed-field gel electrophoresis (PFGE) to determine the physical extent of the deletions. The MluI fragment sizes confirmed the deletions, although the deduced sizes of the most extensive deletions indicated that material had been inserted into the locus.

Electrophoresis, Gel, Pulsed-Field↗
PubMed1993

Specificity and levels of oral and systemic antibodies to Actinobacillus actinomycetemcomitans.

Salivary and gingival crevicular fluid antibodies and systemic antibodies were analysed for levels and specificity against Actinobacillus actinomycetemcomitans components. The major reactivity of salivary and serum IgA1 and IgA2 antibodies to the periodontal pathogen A. actinomycetemcomitans was against bands between 14 and 83 kD for IgA1 and bands between 14 and 68 kD for IgA2 in Western blot. In addition to specific binding, there was also a hitherto unrecognized Fc-mediated binding of IgG antibodies to an A. actinomycetemcomitans component around 50 kD. Serum IgG antibodies to A. actinomycetemcomitans leukotoxin displayed the highest median value and only 1 individual showed salivary IgM antibodies in ELISA. Elevated levels of gingival crevicular fluid IgA2 antibodies indicated a local production of IgA from periodontal tissues. Using synthetic peptides, several distinct epitopes on the leukotoxin were recognized by both salivary and serum IgA antibodies.

Aggregatibacter actinomycetemcomitans↗
PubMed1993

A 40-base-pair duplication in the gp91-phox gene leading to X-linked chronic granulomatous disease.

Chronic granulomatous disease (CGD) is characterized by the inability of the patients' phagocytic leukocytes to generate superoxide. Therefore, these cells fail to kill certain bacteria and fungi. As a result, patients with CGD suffer from recurrent, life-threatening infections with these micro-organisms. Superoxide is produced by NADPH oxidase, a multicomponent enzyme exclusively present in phagocytic leukocytes. The most common form of CGD is X-linked, originating from a deficiency of the high-molecular-weight subunit of cytochrome b558 (gp91-phox). Here we describe a patient suffering from X-linked CGD due to a 40-base-pair duplication in exon 7 of the CYBB gene coding for gp91-phox, predicting a frameshift, substitution of 22 amino acids and a premature stop codon at amino-acid position 253. The mother as well as the grandmother of this patient were proven to be heterozygous for this mutation; the father and sister were normal. However, the great-grandmother proved to have normal oxidative functions, suggesting that the mutation occurred three generations ago. This is the first description of a nucleotide duplication leading to CGD.

Amino Acid Sequence↗