Biomedical subjects

M L Schroeder

Publications and source records attributed to M L Schroeder.

At least 19 recordsLinked to original sources

PubMed2003

Serological identification of a non-HLA antigen in Oriental populations.

In a routine HLA antibody screening cross-match test using the complement-mediated lymphocytotoxicity (LCT) assay, we discovered an antibody, in a transfused Caucasian woman, recognizing an Oriental restricted antigen that does not appear to be associated with the human leukocyte antigen (HLA) system. The distribution of this 'novel' antigen in Oriental populations and its frequency in the Taiwanese Chinese population are reported.

Antigens↗

PubMed2001

V(D)J recombination defects in lymphocytes due to RAG mutations: severe immunodeficiency with a spectrum of clinical presentations.

Severe combined immunodeficiency (SCID) comprises a heterogeneous group of primary immunodeficiencies, a proportion of which are due to mutations in either of the 2 recombination activating genes (RAG)-1 and -2, which mediate the process of V(D)J recombination leading to the assembly of antigen receptor genes. It is reported here that the clinical and immunologic phenotypes of patients bearing mutations in RAGs are more diverse than previously thought and that this variability is related, in part, to the specific type of RAG mutation. By analyzing 44 such patients from 41 families, the following conclusions were reached: (1) null mutations on both alleles lead to the T-B-SCID phenotype; (2) patients manifesting classic Omenn syndrome (OS) have missense mutations on at least one allele and maintain partial V(D)J recombination activity, which accounts for the generation of residual, oligoclonal T-lymphocytes; (3) in a third group of patients, findings were only partially compatible with OS, and these patients, who also carried at least one missense mutation, may be considered to have atypical SCID/OS; (4) patients with engraftment of maternal T cells as a complication of a transplacental transfusion represented a fourth group, and these patients, who often presented with a clinical phenotype mimicking OS, may be observed regardless of the type of RAG gene mutation. Analysis of the RAG genes by direct sequencing is an effective way to provide accurate diagnosis of RAG-deficient as opposed to RAG-independent V(D)J recombination defects, a distinction that cannot be made based on clinical and immunologic phenotype alone.

Alleles↗

PubMed2001

Actinic prurigo: clinical features and HLA associations in a Canadian Inuit population.

BACKGROUND: Actinic prurigo (AP) is an idiopathic familial photodermatitis. AP of the Inuit is rarely reported and poorly characterized. OBJECTIVE: Our purpose was to examine the clinical features and HLA associations of AP in an Inuit population. METHODS: Thirty-seven Inuit subjects with AP were administered a questionnaire and underwent a cutaneous examination. Other causes of photosensitivity were excluded. HLA class I typing was performed by polymerase chain reaction and sequence-specific primers and class II typing by polymerase chain reaction and sequence-specific oligonucleotide probes. RESULTS: Subjects were 81.1% female, 67.6% had a family history of photosensitivity, and all experienced seasonal variation. The average age at onset of photosensitivity was 29 years, and only 27% had a trend toward improvement in photosensitivity. Involvement of eyes and nonexposed skin was reported in 62.2% and 18.9% of subjects, respectively. Physical examination revealed involvement of the face (64.9%), lip (32.4%), ear (13.5%), and dorsal aspect of the hand (24.3%). HLA-DRB1*14 was present in 51.2% of subjects and 26.2% of controls (P =.022, odds ratio = 2.975). This is a previously unreported HLA association. CONCLUSION: AP in the Inuit is a seasonal, pruritic photodermatitis, often commencing in adulthood and worsening over time. A novel association with HLA-DRB1*14 has been discovered. Overall, this novel HLA association, the absence of HLA associations previously reported in non-Inuit populations, and clinical distinguishing features support the concept that AP in the Inuit may have a distinct immunopathogenic basis that translates into a different phenotype. It also raises the question of whether AP in the Inuit is a distinct photosensitivity disorder specific to this group that has been genetically isolated because of geographic and cultural seclusion.

Adult↗

PubMed1999

Axonal regeneration in the central nervous system of aplysia californica determined by anterograde transport of biocytin.

Rhythmic biting, a component of consummatory feeding behavior in the sea hare Aplysia californica, is eliminated following bilateral cerebral-buccal connective (CBC) crushes and recovers within 14 days postlesion. To assess axonal regeneration after CBC lesions, we used biocytin backfills of CBCs followed by fluorescence labeling with streptavidin-lissamine rhodamine. Anterograde transport of biocytin showed up to 1 mm of outgrowth by regenerating axons at 3 days postlesion. At 7 days postlesion, the regenerated axons approached or had entered the ipsilateral buccal neuropil and exhibited numerous varicosities; the average rate of axonal growth was 326 microm/day for the longest, most rapidly growing axons labeled in the CBC. The number of varicosities on labeled axons, suggestive of intercellular interactions, was increased dramatically at all times postlesion. At 14 and 20 days postlesion, regenerated axons branched extensively in the ipsilateral buccal neuropil, entered the contralateral buccal neuropil, and entered peripheral nerves on both sides of the midline. At these later times postlesion, some labeled axons encircled unlabeled buccal cell bodies and exhibited branches containing numerous varicosities, indicative of axosomatic contacts. Some regenerating axons were observed in the sheath of the CBC, but the vast majority of labeled axons remained confined to the connective core, as in control preparations. The bilateral projections within the buccal ganglia of labeled cerebral-to-buccal axons and the large number of varicosities present on these processes are indicative of regenerating axons and synapses that likely contribute to the functional recovery of rhythmic biting.

Animals↗

PubMed1999

Dimensional assessment of personality pathology in patients with eating disorders.

This study examined patients with eating disorders on personality pathology using a dimensional method. Female subjects who met DSM-IV diagnostic criteria for eating disorder (n = 136) were evaluated and compared to an age-controlled general population sample (n = 68). We assessed 18 features of personality disorder with the Dimensional Assessment of Personality Pathology - Basic Questionnaire (DAPP-BQ). Factor analysis and cluster analysis were used to derive three clusters of patients. A five-factor solution was obtained with limited intercorrelation between factors. Cluster analysis produced three clusters with the following characteristics: Cluster 1 members (constituting 49.3% of the sample and labelled 'rigid') had higher mean scores on factors denoting compulsivity and interpersonal difficulties; Cluster 2 (18.4% of the sample) showed highest scores in factors denoting psychopathy, neuroticism and impulsive features, and appeared to constitute a borderline psychopathology group; Cluster 3 (32.4% of the sample) was characterized by few differences in personality pathology in comparison to the normal population sample. Cluster membership was associated with DSM-IV diagnosis -- a large proportion of patients with anorexia nervosa were members of Cluster 1. An empirical classification of eating-disordered patients derived from dimensional assessment of personality pathology identified three groups with clinical relevance.

Adolescent↗

PubMed1997

Two novel mutations in a Canadian family with aspartylglucosaminuria and early outcome post bone marrow transplantation.

Aspartylglucosaminuria (AGU) is a lysosomal storage disease caused by deficiency of aspartylglucosaminidase. The disease is overrepresented in the Finnish population, in which one missense mutation (Cys163Ser) is responsible for 98% of the disease alleles. The few non-Finnish cases of AGU which have been analyzed at molecular level have revealed a spectrum of different mutations. Here, we report two new missense mutations causing AGU in two Canadian siblings. The patients were compound heterozygotes with a G299-->A transition causing a Gly100-->Gln substitution and a T404-->C transition resulting in a Phe135-->Ser change in the cDNA coding for aspartylglucosaminidase. The younger patient recently underwent bone marrow transplantation.

Acetylglucosamine↗

PubMed1996

Pancreatitis post-bone marrow transplantation.

Pancreatitis has been reported as a rare complication after bone marrow transplantation (BMT). This paper reports a series of three cases of pancreatitis post-BMT and reviews the literature. Pancreatitis occurred in three of 68 (4.4%) of BMT cases in our transplant program. The etiology of such cases is multifactorial and includes drugs, graft-versus-host disease, infection, cholecystitis, and the lipid in total parenteral nutrition. Pancreatitis should be included in the differential diagnosis of abdominal pain post-BMT. The development of a pancreatic pseudocyst in an immunocompromised host may require surgical drainage since infected pseudocysts are not drained adequately by radiologically guided techniques.

Adult↗

PubMed1995

P1 blood group antigen expression and epidemic hemolytic uremic syndrome.

P1 blood group positivity has been postulated as a host factor which may provide protection against the development of post-enteropathic hemolytic uremic syndrome (HUS). In this study, blood group status in 20 Inuit survivors of Escherichia coli O157:H7-associated HUS was compared with age- and sex-matched controls from the same community who had experienced uncomplicated diarrheal illness due to the same pathogen. Of 20 HUS survivors, 6 were P1 antigen positive compared with 8 of the 20 controls (P = 0.7). We conclude that P1 antigen positivity was not protective against HUS in this population. Further studies of this condition to clarify the role of host factors in verotoxin-induced endothelial damage are indicated.

Aged↗

PubMed1995

Three new adenosine deaminase mutations that define a splicing enhancer and cause severe and partial phenotypes: implications for evolution of a CpG hotspot and expression of a transduced ADA cDNA.

We report three novel adenosine deaminase (ADA) mutations with interesting implications. A Somali child with severe combined immunodeficiency disease (SCID) had reduced ADA mRNA in T cells and was homozygous for the nonsense mutation Q3X. Unexpectedly, her healthy father was a compound ADA heterozygote whose second allele carried a 'partial' mutation, R142Q, due to a G-->A transition of a CpG dinucleotide. A C-->T transition of the same CpG produced a nonsense mutation, R142X, in two homozygous Canadian Mennonite infants with SCID. The severe and healthy phenotypes associated with R142X and R142Q, the high frequency of 'partial' ADA mutations arising from CpGs in healthy individuals of African descent and the presence of CAA (glutamine) at codon 142 in murine ADA, suggest selection for replacement of this CpG hotspot by CpA during ADA evolution. R142X, located within a purine-rich segment at nt 62/116 of exon 5, caused skipping of the exon, possibly by disrupting a splicing enhancer. Absence of exon 5 in T cell ADA mRNA and low ADA activity in T cells and erythrocytes obtained at age 18-22 months from one of the Mennonite children, indicate limited expression of a normal ADA cDNA from retrovirally transduced CD34+ umbilical cord leukocytes infused shortly after birth in an attempt at stem cell gene therapy.

Adenosine Deaminase↗

PubMed1994

Categorical distinctions in the study of personality disorder: implications for classification.

This article discusses the historical underpinnings of psychiatric classification and examines empirical evidence relevant to (a) whether personality disorders are distinct from each other and from normal personality and (b) whether personality disorders should be classified separately from other mental disorders. At the phenotypic level, research evidence strongly supports the use of a dimensional model to delineate personality disorders; evidence about their genotypic representation is less conclusive though still supportive. Neither empirical nor rational arguments indicate strong justification for separating personality disorders from other mental disorders, as has been done in both the third and fourth editions of the Diagnostic and Statistical Manual of Mental Disorders. Distinctions between abnormal and disordered personality are considered, and suggestions are made for more satisfactory diagnostic classificatory schemes.

Comorbidity↗

PubMed1994

Umbilical cord blood infusion in a patient for correction of Wiskott-Aldrich syndrome.

A 2 3/4 year old male with thrombocytopenia secondary to Wiskott-Aldrich Syndrome (WAS) and a history of two intracranial hemorrhages as well as hemolytic anemia and neutropenia received a placental blood infusion from an HLA-identical female sibling born by caesarian section at 35 weeks gestation. The patient was prepared with Thiotepa and Cytoxan and received a nucleated cell dose of 3.0 x 10(7)/kg. Cyclosporin A and Methylprednisolone was given for graft versus host disease (GVHD) prophylaxis. An ANC of 0.5 x 10(9)/L and 1.0 x 10(9)/L were achieved on post-transplant days 18 and 28, respectively. Platelet recovery was rapid with a platelet count > or = 100 x 10(9)/L on day +39. On posttransplant day +11, the patient developed an erythematous rash consistent with grade I acute GVHD that resolved without therapy. He was discharged day on +60 and has remained free of infections with a normal platelet count off all immunosuppression therapy 30+ months post-transplantation. Chimerism studies performed on peripheral blood mononuclear cells by fluorescent in situ hybridization indicated that the percentage of donor cells ranged between 55 and 80%. The phenotype and function of peripheral blood lymphocytes are completely normal and the patient has responded in vivo with production of antibodies to both diphtheria and tetanus immunizations. This study demonstrates the feasibility of collecting placental blood after a multiple birth delivery and the ability of umbilical cord blood to provide complete hematopoietic and immunologic reconstitution in a patient with WAS.

Antibodies, Bacterial↗

PubMed1994

Failure of passively administered antibody to hepatitis B surface antigen to augment the immune response of a low-responder population to hepatitis B vaccination.

Sixteen renal dialysis patients with documented failure to respond to hepatitis B vaccination in the past were administered passive antibody to hepatitis B surface antigen (anti-HBs) 2 weeks prior to revaccination in an attempt to augment their response to the vaccine. Although 15/16 patients were seropositive for anti-HBs at 1, 3, and/or 6 months following vaccine boost, only 2/13 (15%) remained positive at 12 months, suggesting that the positive findings in the remaining individuals were a result of either passively acquired anti-HBs and/or an active but transient response to the vaccine. As response rates of approximately 5-30% have been reported previously in this population with a vaccine boost in the absence of pre-vaccine passive immunoprophylaxis, these results do not support the use of combined passive/active immunoprophylaxis to augment the immune response to HBV vaccine in low-responder groups.

Aged↗

PubMed1993

Host risk factors for the development of reactive arthritis: a family study.

OBJECTIVE: To determine if the same arthritogenic microorganisms can trigger reactive arthritis (ReA) in both HLA-B27 positive and HLA-B27 negative individuals. To determine risk factors (other than HLA-B27) for the development of ReA. METHODS: Following a common food source outbreak of Salmonella enteritidis, 2 family groups of individuals with dysentery and new onset ReA signs and symptoms were identified. HLA typing was performed for all family members exposed to the dysenteric organism. RESULTS: ReA occurred in HLA-B27 positive members of Family A. No member of Family B possessed HLA-B27 or CREG phenotype, but 3 members developed ReA. The HLA identical sibling of the proband in Family B developed dysentery but did not develop ReA. CONCLUSION: In this epidemic, interaction of the microorganism with an HLA-B27 positive host predictably produced ReA but B27 was not necessary to produce it in other dysenteric patients. Host factors including amount of ingested microorganisms, age and sex but excluding HLA type may account for the differential development of ReA in the siblings in Family B.

Arthritis, Infectious↗

PubMed1992

Factorial structure of traits delineating personality disorders in clinical and general population samples.

Categorical and dimensional models for classifying personality disorders were evaluated by comparing the structure of personality pathology in a clinical sample (n = 158) with the structure in a general population sample (n = 274). Subjects completed 100 personality scales. Separate factor analyses revealed similar structures in the 2 samples. An underlying structure in a combined sample showed limited agreement with the concepts of the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1987). Fifteen factors were retained: Generalized Distress, Rejection, Restricted Expression, Compulsivity, Stimulus Seeking, Insecure Attachment, Diffidence, Intimacy Problems, Oppositionality, Interpersonal Disesteem, Conduct Problems, Cognitive Dysfunction, Affective Reactivity, Narcissism, and Social Apprehensiveness. The results are consistent with a dimensional representation of personality disorder.

Adult↗

PubMed1992

Autoantibodies in chronic arthritis of childhood: relations with each other and with histocompatibility antigens.

BACKGROUND: Studies have shown the presence of either antibodies to histone or anticardiolipin antibodies in some forms of childhood chronic arthritis. The relation between these autoantibodies has not been previously reported, however, and the immunogenetics of their association with childhood arthritis has not been studied. METHODS: The interrelation of fluorescent antinuclear antibodies, antibodies to histone, and anticardiolipin antibodies and their associations with histocompatibility antigens (HLA) were studied in 114 children with chronic arthritis (45 children with pauciarticular onset juvenile chronic arthritis (JCA), 22 with polyarticular onset JCA, 13 with systemic onset JCA, and 34 with juvenile psoriatic arthritis (JPsA). Antibodies to histone and anticardiolipin antibodies were determined in 108 children. HLA antigens (A, B, C, and DR) were studied in the 83 white children. RESULTS: Antibodies to histone occurred in 0% (systemic onset JCA) to 42% (uveitis negative, pauciarticular onset JCA), and anticardiolipin antibodies in 26% (JPsA) to 55% (polyarticular onset JCA) of patients. Only 12 patients (11%) had both antibodies to histone and anticardiolipin antibodies. Neither antibodies to histone nor anticardiolipin antibodies associated with the type of arthritis. Neither of these antibodies alone associated with uveitis. Antibodies to histone were associated with HLA-A2, probably reflecting the known association of HLA-A2 with pauciarticular onset JCA. There was no other HLA association. Fluorescent antinuclear antibodies occurred most often in patients with uveitis; however, the occurrence of fluorescent antinuclear antibodies in patients with pauciarticular onset JCA (the group most at risk for uveitis) was not significantly greater in children with uveitis than in those without uveitis (100 and 88% respectively). CONCLUSIONS: Although antibodies to histone and anticardiolipin antibodies often occur in serum samples from patients with JCA and JPsA, they rarely occur together. Their presence does not associate with uveitis. This study did not show any strong evidence that production of either antibodies to histone or anticardiolipin antibodies in patients with JCA or JPsA is under the control of the histocompatibility locus.

Antibodies, Anticardiolipin↗

PubMed1991

Inherited platelet-storage pool deficiency associated with a high incidence of acute myeloid leukaemia.

A family with an inherited bleeding disorder extending over four generations, and multiple cases of myeloblastic and myelomonoblastic leukaemia was studied. Ten members of the family had, by history, a haemorrhagic diathesis. There were three documented cases of myeloblastic leukaemia, two documented cases of myelomonoblastic leukaemia and two more cases of leukaemia by history. In four of the cases the bleeding diathesis clearly antedated the leukaemia, in two by many years. The bleeding disorder is characterized by a long bleeding time, abnormal platelet aggregation, low platelet ADP and decreased numbers of platelet dense bodies consistent with a dense granule storage pool deficiency. The number of dense granules was decreased by immunofluorescence employing quinacrine or using an antibody to the dense granule membrane protein, granulophysin, confirming an absolute decrease in dense granule numbers rather than the presence of empty granule sacs. This congenital storage pool deficiency is associated with a high incidence of acute myeloid leukaemia in this family.

Acute Disease↗

PubMed1991

An evaluation of DSM-III-R personality disorders.

This study evaluated the extent to which the features of personality disorders are organized into the 11 diagnoses proposed by DSM-III-R. The traits composing personality disorder diagnoses were identified in earlier studies. Seventy-nine traits were required to represent personality diagnoses. Self-report scales were developed to measure each trait. The factorial structure underlying the trait scales was examined in a sample of 158 patients with a primary diagnosis of personality disorder and a sample of 274 general population subjects. Eleven principal components were extracted from each data set and were rotated to the same oblique criterion. The decision to extract 11 components was based on a priori expectations derived from DSM-III-R. Factor comparability coefficients were computed to quantify the similarity of the 2 solutions. A high degree of similarity was observed between the factor structure in the clinical and general population samples, suggesting that features of personality pathology are continuous dimensions. Although a number of factors demonstrated a degree of resemblance to some DSM-III-R diagnostic categories, the overall correspondence was not strong. A second-order factor analysis failed to reproduce the 3 Axis II diagnostic clusters. The results do not support the categorical model used in DSM-III-R and they provide only limited support for DSM-III-R diagnostic concepts.

Adult↗

PubMed1991

Dimensions of personality pathology.

The reliability of DSM-III-R diagnoses of personality disorders is poor and their validity has yet to be established. There is little evidence that the features of personality pathology cluster into these diagnostic entities. For these reasons, it is important to explore alternative ways of classifying personality disorders. In this preliminary study, reliable scales were developed to assess 100 personality dimensions which were systematically developed. The factorial structure underlying the dimensions was evaluated in a heterogeneous sample of 110 subjects from the general population. Sixteen components, accounting for 81.4% of the variance, were retained for rotation to oblique structure. The components were labelled social avoidance, narcissism, insecure attachment, compulsive behaviours, interpersonal disesteem, mobility, anxiousness, conduct problems, stimulus seeking, identity disturbance, self-harm, rejection, diffidence, and hypersensitivity. Two components were not interpreted because they only had one or two salient loadings.

Adult↗