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Biomedical subjects

M L Schroeder

Publications and source records attributed to M L Schroeder.

At least 37 records · Page 2Linked to original sources
PubMed1991

Dimensions of personality disorder. The DSM-III-R cluster B diagnoses.

This study describes a psychometric approach to refining descriptions of antisocial, borderline, histrionic, and narcissistic personality disorders in an attempt to achieve greater distinctiveness. We developed descriptions of each diagnosis from content analysis of the literature. Psychiatrists' ratings were used to organize the features of each diagnosis into a set of carefully defined behavioral dimensions. Self-report scales were developed to assess each dimension. Scales were administered to a general population sample (N = 274) and a sample of patients with a primary diagnosis of personality disorder (N = 133). Scales demonstrated satisfactory levels of internal consistency. Some dimensions showed a low correlation with other dimensions defining the same diagnosis. These dimensions could be eliminated without affecting reliability. The structure underlying the dimensions delineating each diagnosis was evaluated using factor analysis. For each diagnosis, the structure was highly similar in the two samples. Based on these results, specific proposals are made for redefining diagnoses.

Adult↗
PubMed1990

Dimensions of personality disorder. The DSM-III-R cluster A diagnoses.

The authors adopt a construct validity approach to examine the structural validity of diagnoses of paranoid, schizoid, and schizotypal personality disorders. Systematic descriptions of these diagnoses were developed based on features identified from the literature that were organized using the clinicians' ratings. Each diagnosis was described in terms of a series of behavioral dimensions. Sets of behavioral exemplars were developed to assess each dimension. Dimensions and diagnoses were found to exhibit satisfactory levels of internal consistency that were cross-validated in a general population sample of 274 subjects and a clinical sample of 133 patients with a diagnosis of personality disorder. Some dimensions did not correlate highly with the total diagnosis score. Diagnoses could probably be refined by eliminating these dimensions. The structural relationships between dimensions delineating each diagnosis were explored using factor analysis. Diagnoses were not unifactorial. Instead, each diagnosis was found to be composed of two factors. The factorial structure of each diagnosis was found to be similar in the general population and clinical sample. It is suggested that the results support a dimensional representation of these diagnoses using three dimensions: paranoid behaviors, social avoidance, and perceptual cognitive distortion.

Adult↗
PubMed1989

Psoriatic arthritis in children.

A proposed definition of juvenile psoriatic arthritis (JPsA) was used to identify definite or probable JPsA in 35 children. Definite JPsA (24 patients) was defined as arthritis associated, but not necessarily coincident, with a typical psoriatic rash, or arthritis plus at least 3 of 4 minor criteria: dactylitis, nail pitting, psoriasis-like rash, or family history of psoriasis. Probable JPsA (11 patients) was defined as arthritis plus 2 of the minor criteria. In 33 of 35 patients, the onset of arthritis was pauciarticular, but the disease followed a polyarticular course in 23 of 35. Chronic anterior uveitis (6 of 35), antinuclear antibodies (22 of 35), anticollagen antibodies (10 of 35), HLA-DR4 (2 of 28), and HLA-DR8 (5 of 28) occurred with frequencies similar to those seen in patients with juvenile rheumatoid arthritis. JPsA may have more in common with juvenile rheumatoid arthritis than with the seronegative spondylarthropathies with which it is traditionally associated.

Adolescent↗
PubMed1989

A reassessment of the bleeding time: association of age, hematocrit, platelet function, von Willebrand factor, and bleeding time thromboxane B2 with the length of the bleeding time.

In order to provide an overview of the relative contribution of platelet, von Willebrand factor, and other abnormalities to patients with clinical bleeding difficulties, we performed a retrospective survey of coagulation studies on 569 individuals referred to the University of Manitoba coagulation laboratory because they, or a closely related family member, showed clinical evidence of a bleeding disorder. There was a highly significant (p less than 0.001) negative correlation between the bleeding time and each of the following parameters: the platelet count; the hematocrit; the percent aggregation to collagen, epinephrine, ADP, and arachidonic acid; and the logarithm of von Willebrand factor antigen and a measure of its activity (ristocetin cofactor). A significant and independent inverse relationship between the length of the bleeding time and the extent of platelet adhesion to glass beads, patient age, and prothrombin consumption were also observed. Multivariate analysis of the ability of all parameters to predict the bleeding time showed an r2 of only 0.33. Bleeding time thromboxane B2, in a second smaller study of 70 patients, showed a negative correlation with the length of the bleeding time (p = 0.0001), and, when used together with the above parameters, significantly enhanced the ability to predict the length of the bleeding time (r2 = 0.55). Defects in platelet function, as measured in vitro, and significant enough to have an effect on the bleeding time, occurred with greater frequency than defects in von Willebrand factor in the Manitoba patients evaluated.

Adolescent↗
PubMed1988

Analysis for linkage between F13A and three chromosome 6 marker loci: evidence for 6pter:F13A:HLA:GLO1:cen gene order.

The results of the present study provide independent support for F13A:HLA linkage and refine the F13A:HLA and F13A:GLO1 linkage relationships. Analysis of the corresponding recombination fractions for the total paternal F13A:HLA and F13A:GLO1 peak lod scores (z) indicates a locus order of 6pter:F13A:HLA:GLO1:cen. Lod scores between F13A and PLG, a locus recently assigned to chromosome 6, exclude close linkage between these loci.

Child↗
PubMed1987

Immunity to soluble retinal antigen in patients with uveitis accompanying juvenile rheumatoid arthritis.

Studies of immunity to bovine soluble retinal antigen (antigen S) were carried out using serum and peripheral blood lymphocytes from children with juvenile rheumatoid arthritis and chronic anterior uveitis (JRA-uveitis), children with JRA alone, children with nonrheumatic diseases, and controls who had no ocular or rheumatic disease. Enzyme-linked immunosorbent assay and the lymphocyte transformation assay were used to determine immunity. Antibody to antigen S was present significantly more frequently in children with JRA-uveitis than in children with JRA alone, children with nonrheumatic disorders, or controls. These latter groups did not differ in positivity for this antibody. Lymphocyte transformation occurred more frequently in children with JRA-uveitis than in children with JRA alone or controls. Children with JRA alone and controls had similar frequencies of lymphocyte transformation positivity. Enzyme-linked immunosorbent assay positivity and lymphocyte transformation positivity tended to occur in different children. Children with JRA-uveitis who had HLA-B35 had the highest frequency of antibody to antigen S. Immunity to antigen S may be the result of ocular damage by mechanisms other than a pathogenic mechanism per se.

Adult↗
PubMed1986

Rheumatic diseases in an Inuit population.

Prevalence and incidence rates for rheumatic diseases were found to be minimal among the Inuit people in the Keewatin District of the Northwest Territories, Canada. Patient identification was achieved by a review of medical records. All identified patients were interviewed and examined by a participating rheumatologist. Among women, the prevalence of rheumatoid arthritis, adjusted for age of the Manitoba population, was 1,822 per 100,000 and was comparable with that observed in other populations; no cases of rheumatoid arthritis in men were confirmed. The age-adjusted prevalence of osteoarthritis, 1,219 per 100,000 in men and 2,144 per 100,000 in women, was apparently low. A moderately high incidence of Reiter's syndrome, 24.9 per 100,000, was found. The findings in children suggested a high frequency of seronegative spondylarthropathies (yearly incidence 60.1 per 100,000), although the adjusted yearly incidence for juvenile rheumatoid arthritis also appeared to be high, 23.6 per 100,000. The frequencies of HLA antigens in patient groups were compared with those found in 19 patients with musculoskeletal complaints but no rheumatic disease. Both HLA-B27 and HLA-DR4 appeared to be common in these controls, 36.8% and 63.2%, respectively. Nevertheless, there was a higher frequency of HLA-B27 in patients with seronegative spondylarthropathies (87%) than in controls (P = 0.001). Because of the small numbers of patients who had rheumatoid arthritis, no associations with HLA were made for this condition. Although the findings suggest differences in the distribution of rheumatic diseases compared with those found in other populations, more complete studies are required to confirm these observations.

Adult↗
PubMed1986

Penicillamine-induced proteinuria: risk factors.

Twenty-six of 300 patients (9%) with rheumatoid arthritis (RA) developed penicillamine-induced proteinuria. The mean daily dose and duration of therapy at onset of proteinuria were 591 mg and 9 months, respectively, while the mean duration of proteinuria was 5.5 months. However, six patients developed proteinuria at 250 mg/d and six after 9 months of therapy. Twelve patients were successfully either restarted (five) or maintained (seven) on penicillamine with resolution of proteinuria. No permanent renal impairment occurred. Positive risk factors included the presence of HLA-B8 and DR3 and prior gold-induced proteinuria. Patients with prior gold-induced proteinuria should be observed more carefully, but tissue typing is not recommended as proteinuria is reversible. Furthermore, penicillamine can be restarted or maintained in these patients if the RA has responded favorably to the drug.

Adult↗
PubMed1986

Canine platelet alloimmunization: the role of donor selection.

Five different platelet transfusion programmes were evaluated in a canine model to determine the most effective method of providing long-term platelet support. When a weekly transfusion from a single unrelated donor was used, alloimmune platelet refractoriness developed in 95% of recipients after an average of 3.1 +/- 0.7 transfusions, and donor platelets circulated for a total of 8.2 +/- 2.3 d. When multiple unrelated donors were used, the percentage of refractory recipients was similar (60% versus 77%) whether platelets came from six single donors given sequentially or from a pool of the same six donors given repeatedly. There was, however, a significant difference in the number of transfusions given prior to immunization (14 +/- 5 transfusions lasting 32 +/- 12 d for sequential single donors as compared to 5.5 +/- 1.0 transfusions lasting 13 +/- 2 d for the pooled donors). When littermates were used as platelet donors, the frequency of refractory recipients, the number of transfusions required to immunize, and the circulation time of donor platelets before refractoriness was not better than when multiple unrelated single donors were used. Furthermore, there was no significant difference in effectiveness between DLA-identical and DLA-nonidentical littermate platelet donors. In recipients previously immunized by a pool of six unrelated donors, the same percentage of recipients was refractory to DLA-identical littermate donors as had been observed following only DLA-identical platelet transfusions. This suggests that non-DLA immunizing platelet antigens, not shared between approximately 30% of DLA-identical littermates, are well represented in a random canine population. However, prior random transfusions did not compromise long-term platelet support from 'truly' platelet compatible DLA-identical littermate donors. These studies indicate that single donor transfusions either from littermates or sequential unrelated donors are the most effective method of providing long-term platelet support. However, the use of pooled unrelated donor transfusions, followed by DLA-identical donors in immunized recipients is an equally acceptable alternative.

Animals↗
PubMed1985

Pokeweed mitogen and Staphylococcus aureus Cowan I induced immunoglobulin A synthesis by lymphocytes of IgA deficient blood donors.

In vitro IgA synthesis induced by pokeweed mitogen (PWM), Staphylococcus aureus Cowan I (STA), and combinations of STA and PWM (STA/PWM) was studied in lymphocytes of IgA deficient (sIgAd) blood donors. Cultures of T-depleted (non-T) cells with autologous or allogeneic control T, irradiated T (T), or T4 cells suggested abnormalities in non-T cell fractions in most (12/22) sIgAd donors. T cell abnormalities in themselves, detectable in six donors, did not appear to account for the failure of IgA synthesis. Repeat studies in 10 donors indicated fluctuations in in vitro IgA synthesis in four. IgA synthesis induced by STA/PWM combinations was observed in only one of eight sIgAd donors. Our findings suggest that in some donors defects leading to failure to produce IgA may not be constant and support the hypothesis of a maturation arrest in IgA+ B cells in sIgAd donors.

B-Lymphocytes↗
PubMed1984

Shortening of bleeding time by 1-deamino-8-D-arginine vasopressin in various bleeding disorders.

To evaluate the effect of 1-deamino-8-D-arginine vasopressin (DDAVP) in various bleeding disorders, 10 micrograms/m2 DDAVP was administered to subjects with von Willebrand disease (13), platelet function defects (12), von Willebrand disease and platelet defects together (8), or isolated prolongation of the bleeding time (5). DDAVP shortened the bleeding time similarly in all patient groups. Shortening of the bleeding time was also observed in 2 patients with aspirin-induced platelet defects and in 2 normal subjects. DDAVP administration was associated with falls in the platelet count, mean platelet volume, and partial thromboplastin time, and rises in platelet adhesion, factor VIII coagulant activity, factor VIII related antigen, and von Willebrand factor activity. The basal bleeding time was the only predictor of the magnitude of the bleeding-time correction. Normal haemostatis was achieved with DDAVP plus epsilon-aminocaproic acid and no blood product support during operations in 18 patients with bleeding disorders.

Adolescent↗
PubMed1984

Homocystinuria and megaloblastic anemia responsive to vitamin B12 therapy. An inborn error of metabolism due to a defect in cobalamin metabolism.

We describe an inborn error of vitamin B12 metabolism in an infant who had severe developmental delay, megaloblastic anemia, and homocystinuria. There was no evidence of methylmalonic aciduria or deficiency of folate or vitamin B12. Treatment with hydroxocobalamin, but not with cyanocobalamin and folic acid, resulted in rapid clinical and biochemical improvement. Cultured fibroblasts showed an absolute growth requirement for methionine, defective incorporation of radioactivity from [14C]5-methyltetrahydrofolate into protein, and normal incorporation of radioactivity from [14C]propionate, thus assigning the intracellular defect to methionine synthesis. The proportion of intracellular methylcobalamin in the fibroblasts was decreased, but that of 5'-deoxyadenosylcobalamin was normal. Methionine synthetase activity in cell extracts was normal, as was cobalamin incorporation into cultured cells. This defect differs from those described previously in being limited to methylcobalamin accumulation and defective use of 5-methyltetrahydrofolate by intact cells with normal activity of methylmalonyl CoA mutase.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1984

Pulmonary complications in patients receiving granulocyte transfusions and amphotericin B.

To evaluate the possibility that in febrile granulocytopenic patients amphotericin B given along with granulocyte transfusions could increase the incidence of pulmonary complications, we studied 43 severely granulocytopenic patients during 46 episodes of fever. Granulocytes were administered as part of the clinical protocol to all 19 patients who had clinically or microbiologically documented infection; the other 24 patients were randomly allocated to treatment with granulocytes (13 patients) or without granulocytes (11 patients). In all, 32 patients received granulocyte transfusions during 35 episodes of fever. Pulmonary complications developed in six patients in each of the two randomized groups. The incidence of pulmonary complications was not influenced by the number of granulocyte transfusions or by the number of granulocytes per transfusion. Pulmonary complications were significantly more likely to occur in patients with fungal infections. Amphotericin B was given according to clinical indications; 21 patients in all received it. Survival was significantly poorer in patients with pulmonary complications, but the administration of amphotericin B was not related either to survival or to the incidence of pulmonary complications. We conclude that pulmonary complications and poor prognosis are related to underlying pulmonary fungal infection and not to any interaction between amphotericin B and granulocyte transfusions.

Adult↗
PubMed1984

Selected adverse reactions of D-penicillamine.

Selected adverse reactions of penicillamine encountered in our clinic since 1975 are described. They include: proteinuria (26 cases), lupus erythematosus (six cases), myasthenia gravis (two cases), pemphigus (three cases), obliterative bronchiolitis (two cases) and obstructive jaundice (one case).

Adult↗