A Point Mutation Creating a 3' Splice Site in Is a Predominant Cause of C8α-γ Deficiency in African Americans.

C8α-γ deficiency was examined in four unrelated African Americans. Two individuals were compound heterozygotes for a previously reported point mutation in exon 9. mRNA from the remaining six alleles contained a 10 nt insertion between nt 992 and 993 corresponding to the junction between exons 6 and 7.

A 9-year-old boy with chronic urticaria and progressive spondyloarthritis.

A 9-year-old African American boy presented with chronic urticaria and progressive spondyloarthritis. Laboratory tests were abnormal for persistently positive antinuclear antibodies and undetectable total hemolytic complement (CH50) despite normal levels of complement C2, C3, and C4. Ultimately, further testing revealed an underlying deficiency in the immune system that may be associated with autoimmune disease and thus have a bearing on the patient's urticaria and spondyloarthritis.

Autoantibody stabilization of the classical pathway C3 convertase leading to C3 deficiency and Neisserial sepsis: C4 nephritic factor revisited.

C3 deficiency is a rare disorder that leads to recurrent pyogenic infections. Here we describe a previously healthy 18 y/o Caucasian male with severe meningococcal disease. Total hemolytic activity was zero secondary to an undetectable C3.

The complement system in pediatric systemic lupus erythematosus, atypical hemolytic uremic syndrome, and complocentric membranoglomerulopathies.

Purpose Of Review: This review summarizes the recent advances in complement biology and the evolving understanding of these contributions to the pathophysiology and treatment of predominantly pediatric disease syndromes.

Recent Findings: Identification of lupus patients with complete deficiencies of one of the plasma complement proteins enabled the field to move beyond the notion of complement as a laboratory curiosity. Clinical investigation of the manifestations observed in deficient patients has further defined the biology of the system in normal individuals.

Challenges and opportunities facing medical education.

Medical education is at a crossroads. Although unique features exist at the undergraduate, graduate, and continuing education levels, shared aspects of all three levels are especially revealing, and form the basis for informed decision-making about the future of medical education.This paper describes some of the internal and external challenges confronting undergraduate medical education.

Immunoglobulin deficiencies and susceptibility to infection among homozygotes and heterozygotes for C2 deficiency.

About 25% of C2-deficient homozygotes have increased susceptibility to severe bacterial infections. C2-deficient homozygotes had significantly lower serum levels of IgG2, IgG4, IgD, and Factor B, significantly higher levels of IgA and IgG3 and levels of IgG1 and IgM similar to controls. Type 1 (28 bp deletion in C2 exon 6 on the [HLA-B18, S042, DR2] haplotype or its fragments) and type II (non-type I) C2-deficient patients with increased susceptibility to bacterial infection had significantly lower mean levels of IgG4 (p < 0.

Lipooligosaccharide P(k) (Galalpha1-4Galbeta1-4Glc) epitope of moraxella catarrhalis is a factor in resistance to bactericidal activity mediated by normal human serum.

Moraxella catarrhalis is a respiratory pathogen responsible for acute bacterial otitis media in children and exacerbation of chronic bronchitis in adults. M. catarrhalis strains are frequently resistant to the bactericidal activity of normal human serum.

High prevalence of complement component C6 deficiency among African-Americans in the south-eastern USA.

Complement component C6 is a part of the membrane attack complex that forms a pore-like structure in cell membranes following complement activation. Deficiency of terminal complement components including C6 predisposes individuals to infection with Neisseriae. Using polymerase chain reaction/single-strand conformation polymorphism analysis followed by DNA sequencing, we screened genomic DNA from 200 randomly chosen blacks and an equal number from whites for three loss-of-function C6 mutations.

Teaching a screening musculoskeletal examination: a randomized, controlled trial of different instructional methods.

Purpose: To develop and test a program to teach a rapid screening musculoskeletal examination.

Method: In 1995, 191 medical and physician assistant students were randomized to four intervention groups: written materials only (n = 47), written materials and videotape (n = 46), written materials and small-group sessions facilitated by fourth-year medical students (n = 55), and all three methods (n = 43). Assessments, in the form of a written test and standardized patient examinations, were conducted before the interventions (n = 40 randomly selected students), seven to ten days and again three months after the interventions (n = all 191 students), and 16 months after the interventions (n = 103 students).

A generalizability study of a new standardized rating form used to evaluate students' clinical clerkship performances.

Purpose: To investigate the measurement characteristics of standardized clinical evaluation forms (CEFs) used to assign grades for clerkship performance.

Method: In 1996-97, the authors reviewed 5,168 CEFs completed for 175 students in eight clerkships. Limiting their analysis to the three clerkships that produced the most CEFs, the authors conducted a generalizability study to determine the five variance components for each clerkship.

Heterozygous C8beta complement deficiency does not predispose to meningococcal disease.

We have identified 42 Russian patients with homozygous C8beta complement component deficiency, all of whom had experienced at least one episode of systemic meningococcal disease. About 90% of these individuals have a C --> T exchange in exon 9, leading to a premature stop codon. If, like the homozygous-deficient state, heterozygous C8beta deficiency constitutes a risk factor for meningococcal disease, it would be expected to be detected with increased frequency among individuals suffering from this disease.

Student health policies of U.S. medical schools.

Background: Medical students are at risk of exposure to bloodborne pathogens, yet few data are available about U.S. medical schools' policies to protect students.

Type II human complement C2 deficiency. Allele-specific amino acid substitutions (Ser189 --> Phe; Gly444 --> Arg) cause impaired C2 secretion.

Type II complement protein C2 deficiency is characterized by a selective block in C2 secretion. The Type II C2 null allele (C2Q0) is linked to two major histocompatibility haplotypes (MHC) that differ from the MHC of the more common Type I C2 deficiency. To determine the molecular basis of Type II deficiency the two Type II C2Q0 genes were isolated and transfected separately into L-cells.

Invasive Haemophilus influenzae type b infection in a child with familial deficiency of the beta subunit of the eighth component of complement.

A child who had had meningitis caused by Haemophilus influenzae type b, and then had meningococcal meningitis, was found to have familial deficiency of the beta subunit of the eighth component of complement. The child had not received the H. influenzae type b vaccine.

Delineation of additional genetic bases for C8 beta deficiency. Prevalence of null alleles and predominance of C-->T transition in their genesis.

We studied the molecular bases for C8 beta deficiency in 34 unrelated families from the United States and the former Soviet Union. These families represented 69 unrelated null alleles of which 59 (86%) were found to be due to a previously described C-->T transition in exon 9. Six additional null alleles were also caused by C-->T transitions, of which four (6%) were located at base 388 in exon 3, one (2%) at base 298 in exon 3, and one (2%) involved cytosine 847 in exon 6.

Cloning and characterization of the cDNA encoding guinea-pig properdin: a comparison of properdin from three species.

The cDNA sequence encoding properdin was generated from guinea-pig spleen RNA by the reverse transcription-polymerase chain reaction. This sequence was approximately 75% homologous with human and 71% homologous with murine properdin at the nucleic acid level. Guinea-pig properdin had six thrombospondin repeat sequences consisting of about 60 amino acids, each with six cysteine and three tryptophan residues.

Multicenter comparison of Neisseria meningitidis serogroup C anti-capsular polysaccharide antibody levels measured by a standardized enzyme-linked immunosorbent assay.

A standardized enzyme-linked immunosorbent assay (ELISA) was used by 11 laboratories to measure levels of total serum antibody to Neisseria meningitidis serogroup C capsular polysaccharide in 16 unpaired pre- and postvaccination serum samples. Twelve serum samples were from adults, and four were from children aged 2, 3, 5, and 9. The between-laboratory coefficient of variation for pre- and postvaccination sera ranged from 16 to 59% and 11 to 21%, respectively.

Vaccination and the role of capsular polysaccharide antibody in prevention of recurrent meningococcal disease in late complement component-deficient individuals.

This study sought to quantitate the response of late complement component-deficient (LCCD) individuals to the meningococcal vaccine, to examine antibody persistence, and to investigate the contribution of these antibodies to meningococcal killing in complement- and phagocyte-dependent bactericidal assays. The mean concentration of antibody to group A and C capsular polysaccharide after vaccination was similar in 8 LCCD, 11 family members, and 7 unrelated normal individuals. LCCD individuals had a greater percentage decline in antibody concentration to group C polysaccharide and had lower concentrations of antibody to group Y polysaccharide 2.