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Biomedical subjects

V Hanson

Publications and source records attributed to V Hanson.

At least 19 recordsLinked to original sources
PubMed1999

Regulation of the neuron-specific exon of clathrin light chain B.

Clathrin light chain B (LCB) is a major component of clathrin coated vesicles, which are structures involved in intracellular transport. A neuron-specific isoform of LCB is generated by incorporation of a single exon (EN) using an alternative splicing mechanism that reflects the special demands of neurons, such as axonal transport and synaptic neurotransmission. Here, we demonstrate that this neuron-specific exon is developmentally regulated and is excluded in non-neuronal cells because its 5' and 3' splice sites deviate from the mammalian consensus sequences. A gel retardation assay indicated the presence of a developmentally regulated factor in brain that binds to the neuronal exon. In addition, EN usage is repressed by increasing the concentration of htra2-beta1, a splice factor whose isoform expression is influenced by neuronal activity. We propose that a brain-specific factor is involved in EN recognition during development and adulthood. In addition, ubiquitously expressed splicing factors such as htra2-beta1 are involved in regulating EN expression in the adult brain.

Age Factors↗
PubMed1999

Use of physician and acute care services by persons with and without Alzheimer's disease: a population-based comparison.

OBJECTIVE: To estimate differences in use of acute care services between persons with and without Alzheimer's disease (AD). STUDY DESIGN: Population-based historical cohort study. SETTING/SUBJECTS: All Rochester, Minnesota, residents with AD onset between January 1, 1980, and December 31, 1984 (n = 301), plus one age- and sex-matched nondemented control per case, were identified with a retrospective review of community-based medical records. MEASUREMENTS: Cases and controls were followed in their medical records for number of acute care encounters in the year before January 1 of the index year (year of onset for AD case and their matched control) and in the 4 years following December 31 of the index year. Encounters included clinician visits (office or nursing home), emergency room (ER) visits, hospitalizations (inpatient and outpatient), and inpatient days. Multivariate regression analyses were adjusted for age, sex, pre-index level of illness, and follow-up time. RESULTS: In the pre-index period, cases and controls were similar with respect to level of illness, number of office visits, ER visits, and hospitalizations. In the year before AD onset, 17 cases (7%) had a clinician visit in the nursing home compared with no controls. In the 4 years after the index year, mean length of follow-up was 3.4 years for both cases and controls. The numbers of ER visits, hospitalizations, and inpatient days were similar for cases and controls. Sixty-four percent of AD cases had a clinician visit in a nursing home versus 1% of controls. Controls experienced more office visits than cases (median = 16 vs 10, P < .001). CONCLUSIONS: The onset of AD is not associated with greater use of acute care services. However, neither is the high use of nursing home care offset by fewer ER or hospital encounters.

Acute Disease↗
PubMed1998

PMA-induced reduction in invasiveness is associated with hyperphosphorylation of MARCKS and talin in invasive bladder cancer cells.

Protein kinase C (PKC) plays a critical role in signal transduction for a variety of cell activation processes. Enhanced PKC activity is often found in cancer cells that show marked invasive and/or metastatic potential. Thus, a specific PKC inhibitor may serve as a tool to reduce invasive or metastatic potential of cancer cells. We show here that phorbol 12-myristate 13-acetate (PMA), a PKC activator, also reduces invasiveness of EJ invasive transitional carcinoma cells. PMA-induced reduction in invasiveness was parallel with inhibition of cell motility. PMA neither induced E-cadherin expression nor augmented cell-matrix adhesion of EJ cells. PMA caused retraction of microspikes from the rim of the cells and consequently rounding of the cellular rim, and the disappearance of microfilaments from the cytoplasm. PMA at 10(-7) M, at which concentration the motility of EJ cells was completely inhibited, down-regulated PKC activity over 5 hr after transient translocation of PKC activity to the membrane fraction. At the same time, PMA induced hyperphosphorylation of MARCKS and talin. During the process of cell movement, actin-binding proteins are in a cycle of phosphorylation and dephosphorylation. Once this cycle is interrupted, cells can no longer maintain the dynamics of cytoskeletal structure. We suggest that retention of the hyperphosphorylated state of MARCKS and talin is responsible for the mechanism(s) by which PMA produces inhibitory activity against invasiveness of EJ cells.

Actins↗
PubMed1992

Neuromuscular junctions contain NP185: the multifunctional protein is located at the presynaptic site.

The NP185 polypeptide (AP3) is a multifunctional component isolated from brain endocytic vesicles, which binds to tubulin and clathrin light chains, decoated vesicles, synaptic vesicles, and the synaptosomal plasma membrane (Su et al., 1991). The NP185 molecules are expressed during avian cerebellar synaptogenesis and appear to function in CNS regions rich in synaptic terminals (Perry et al., 1991). In this report we describe double-labelling experiments with avian embryonic striated muscle fibers demonstrating the exclusive presence of the brain-specific protein at the neuromuscular junction. We used indirect rhodamine immunofluorescence labeling with a monoclonal antibody (mAb-8G8) to mark the location of NP185 in muscle combined with fluorescein-alpha-bungarotoxin to mark the postsynaptic location of the acetylcholine receptors (AChRs). We show that the distribution of both NP185 and AChRs has an overall correlation, but the location of NP185 is circumscribed to presynaptic structures adjacent but not overlapping with postsynaptic structures displaying the AchRs. To confirm the identity of NP185, the molecule was extracted from both tissues, partially purified, immunoprecipitated, and identified in Western blots with the mAb 8G8. The mAb reacted with an identical 185 kD protein band purified from both tissues. Based on its properties and specific neuronal location, the NP185 molecule may function in motor nerve terminals by screening membrane proteins, identifying areas of the synaptic plasma membrane, and to anchor these elements with structural proteins for their recycling and transport within the neuronal cellular compartments.

Adaptor Protein Complex 3↗
PubMed1992

Lupus nephritis: prognostic factors in children.

As newer treatment modalities become available for patients with severe lupus nephritis, it becomes increasingly important to identify patients at risk for renal failure. In this study, the records of 90 children presenting with systemic lupus erythematosus over a 13-year period were reviewed. Nineteen were lost to follow-up prior to completion of the study. Of the 71 remaining children, 16 (22%) progressed to chronic renal failure. Persistent hypertension lasting greater than 4 months, anemia, abnormalities of the urinalysis, and elevated serum creatinine level were significantly associated with progression to renal failure. Sex, race, age, abnormalities of creatinine clearance, and 24-hour urine protein collection were not associated with progression to renal failure. Renal biopsies were obtained in 45 children. Biopsies were initially classified according to World Health Organization criteria. Diffuse proliferative glomerulonephritis was significantly associated with progression to renal failure. The 45 biopsies available were reviewed by one of the authors and categorized by activity and chronicity indices. Both the active lesions of fibrinoid necrosis, synechiae, tubular casts, and vasculitic lesions and the chronic lesion of glomerular sclerosis correlated with progression to renal failure. Of the 16 children who progressed to renal failure, 2 had cadaver kidney transplants and are well 5 years posttransplant; 4 had fulminant lupus and died within 1 month of commencing dialysis; 10 began chronic dialysis. Five of the 10 children on chronic dialysis died from sepsis. These data suggest that children with systemic lupus erythematosus who undergo dialysis do poorly.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1991

Neuronal specific protein NP185 is enriched in nerve endings: binding characteristics for clathrin light chains, synaptic vesicles, and synaptosomal plasma membrane.

The neuronal specific protein NP185, found associated with brain clathrin-coated vesicles, formed a complex with unphosphorylated, but not with phosphorylated, clathrin light chains. The NP185-clathrin light chain complex was associated with casein kinase II activity, which, in the presence of polylysine, phosphorylated clathrin light chain b but not the NP185. The dissociation of this complex with 50% ethylene glycol pH 11.5 suggests that NP185 binds to hydrophobic domains of clathrin light chains. When NP185 molecules were retained by monoclonal antibody-linked Sepharose beads, they bound synaptic vesicles, decoated vesicles and synaptosomal plasma membrane. Immunohistochemistry on mouse cerebellar tissue sections using 8G8, a monoclonal antibody raised against NP185, showed neuronal specific labeling closely following synaptic distribution. In immunoblots, NP185 shares similar epitopes to those detected in another assembly polypeptide, AP-180, an indication that both proteins are identical. It appears that NP185 plays a specific role in nerve ending functions through its ability to induce clathrin to polymerize into cages, its interaction with synaptic vesicles, with the plasma membrane and with clathrin coat components.

Adaptor Proteins, Vesicular Transport↗
PubMed1991

Neuronal protein NP185 in avian and murine cerebellum: expression during development and evidence for its presence in nerve endings.

The neuronal protein NP185 is a neural tissue-specific protein isolated from clathrin-coated vesicles in brain. Using 8G8, a monoclonal antibody (MAb) characterized in our laboratory, we studied the expression and distribution of neuronal protein NP185 in developing avian cerebellum and in mature murine cerebellum. Furthermore, we compared these parameters to that of synapse-specific neuronal protein, synaptophysin, and an axon-specific (i.e., non-synaptic) neuronal protein, neurofilament NF68. We found that NP185 expression temporally and spatially corresponds to avian cerebellar synaptogenesis. In addition, NP185 distribution parallels synaptophysin distribution throughout development, while differing from that of either unassembled or filamentous forms of NF68. The evidence also suggests that embryonic NP185 expression coincides with synaptogenesis, and that NP185 remains concentrated in the terminal boutons of mature neurons. The synapse specificity of NP185 and the recent biochemical properties reported for this protein support the postulate that this molecule may trigger synaptic events and distinguish structurally and functionally active synapses.

Adaptor Proteins, Vesicular Transport↗
PubMed1990

Novel proteins mediate an interaction between clathrin-coated vesicles and polymerizing actin filaments.

A monoclonal antibody, A-7C11, was generated which reacts with two polypeptides of 40 kDa and 80 kDa associated with the coat proteins of purified brain clathirn-coated vesicles. The 40-kDa antigen was purified and found to display actin-binding properties. Negative-staining electron microscopy showed that one of the antigens reactive with A-7C11 appears to mediate the association of isolated clathrin-coated vesicles with assembling actin filaments in vitro. Immunofluorescence microscopy of cultured fibroblasts with A-7C11 revealed the antigens aligned with both actin filaments and as punctate structures near the plasma membrane. The data suggest that the interaction between clathrin-coated vesicles and the actin cytoskeleton is mediated by antigens identified by monoclonal antibody A-7C11.

Actins↗
PubMed1990

High prevalence of IgA rheumatoid factor in severe polyarticular-onset juvenile rheumatoid arthritis, but not in systemic-onset or pauciarticular-onset disease.

The presence of IgA rheumatoid factor (IgA-RF) has been correlated with severe joint disease in adult rheumatoid arthritis (RA), but IgA-RF has not been reported in juvenile rheumatoid arthritis (JRA). In the present study, IgA-RF was assayed by an enzyme-linked immunosorbent assay and was found in the sera of 14 of 24 children (58%) with active polyarticular JRA. The presence of IgA-RF correlated with the degree of functional disability. In contrast, IgA-RF was not found in the sera of systemic-onset disease patients, regardless of the degree of dysfunction. IgA-RF was detected in only 1 patient with pauciarticular disease, despite the fact that several patients in this group had severe disease. The presence of IgA-RF in polyarticular JRA did not correlate with serum IgA levels, but did correlate with the presence and the level of serum IgM-RF. Thus, the presence of IgA-RF appears to be specific for polyarticular JRA, and shows a correlation with severe disease in this group.

Adolescent↗
PubMed1990

Prevalence and concentration of IgM rheumatoid factor in polyarticular onset disease as compared to systemic or pauciarticular onset disease in active juvenile rheumatoid arthritis as measured by ELISA.

The prevalence and concentration of IgM rheumatoid factor (RF) in children with juvenile rheumatoid arthritis (JRA) and its major disease onset groups remains uncertain. In our study enzyme linked immunoabsorbent assay (ELISA) of 68 children with active JRA showed IgM RF in the area of 67% (16/24) of those with polyarticular onset disease, 26% (7/27) of those with systemic onset disease, and 6% (1/17) of those with pauciarticular onset disease. The median IgM RF concentration was 50-fold higher in polyarticular disease compared to systemic disease. The prevalence of IgM RF in polyarticular disease was greater in those with severe disease (functional classes and 3 and 4), with 90% (9/10) seropositive. By agglutination assay, the prevalence of IgM RF in JRA was significantly less than by ELISA, with 33% of the polyarticular group positive for IgM RF, and none of the systemic group positive, Relatively low concentration IgM RF similar to that seen in systemic JRA was also found in high prevalence in the area of children with non-JRA, systemic rheumatic disease (n = 8). In summary, our study shows by ELISA that high concentrations of IgM RF are found essentially only in the sera of children with polyarticular onset JRA and especially in those with severe disease.

Adolescent↗
PubMed1989

Systemic lupus erythematosus in the first decade of life.

To evaluate whether the onset of systemic lupus erythematosus in the first decade of life was associated with a unique pattern of racial preponderance, sexual preponderance, genetic predisposition, or disease expression, the medical records of 23 children with systemic lupus erythematosus prior to their tenth birthdays were compared with the medical records of 82 children in whom lupus was diagnosed between their tenth and 20th birthdays. No statistically significant differences in sex distribution, racial (ethnic) background, family history, mode of onset, morbidity, or mortality rates were found between the two age groups. The frequently held view that children with early-onset lupus do worse probably relates to the fact that even though they survive as long as children with the older-onset disease, they die younger because they have the onset of their lupus at a younger age.

Adolescent↗
PubMed1988

Required surgical therapy in the pediatric patient with dermatomyositis.

A review of 96 patients with the established diagnosis of childhood dermatomyositis revealed that 15 patients required surgical therapy in addition to diagnostic biopsy. Four of the patients had perforation of the esophagointestinal tract, and 11 required surgical therapy for abscesses, calcific deposits, or treatment of pneumothorax. The life-threatening lesions were perforations of the esophagus and intestine. The best surgical therapy is closure, resection, and adequate drainage. Prognosis depends on treatment of the underlying medical disease.

Abscess↗
PubMed1988

Mediating effects of family social support on child psychological adjustment in juvenile rheumatoid arthritis.

This study assessed the mediating effects of social support on psychological adjustment in children having to cope with the ongoing chronic strain of juvenile rheumatoid arthritis. Disease activity, family social support, and peer social support were entered into hierarchical multiple regression analyses to statistically predict internalizing and externalizing behavior problems. Family social support was a statistically significant predictor of child psychological adjustment for both internalizing and externalizing behavior problems, accounting for 22% of the variance in each. These findings are consistent with the stress-social support-psychological adjustment relationship that has received empirical attention in studies on physically healthy children. The results are discussed in terms of their implications for primary and secondary prevention efforts for those chronically ill and handicapped children who are at increased risk for psychological adjustment problems.

Adaptation, Psychological↗
PubMed1987

Pediatric rheumatology: a personal perspective.

It is suggested that we make a discussion of the fundamental aspects and problems of scientific investigation a part of all pediatric rheumatology meetings as long as needed. It will be important to look for new directions for research, instead of just following the lead of adult rheumatologists.

Arthritis, Juvenile↗
PubMed1986

A study of classification criteria for a diagnosis of juvenile rheumatoid arthritis.

Criteria for the classification of juvenile rheumatoid arthritis were analyzed in a detailed database of 250 children in order to assess the accuracy of diagnosis and validity of onset types and course subtypes. A number of conclusions have been derived from this study: All definitions of the 1973 criteria for classification of juvenile rheumatoid arthritis should be retained. The addition of onset types to the 1976 revision of the criteria has been validated. The course of the disease after the onset period of 6 months is as important to the outcome of a group of children as is the onset type. The current classification should be broadened to include the course subtypes.

Age Factors↗
PubMed1986

Psychosocial aspects of juvenile rheumatoid arthritis.

The earliest studies dating back to the 1950s have tended to present a more pessimistic view of the psychosocial aspects of JRA patients. More carefully designed studies, however, have shown that these children do not have unique personality characteristics, nor are they necessarily socially maladjusted. Stress may play some role in onset of exacerbation of the disease, although this role is unclear at present. The child's level of cognitive development probably does play a role in the perception of pain and should be considered when undertaking patient education. The long-term psychosocial outcome of JRA patients appears to be quite good, with the majority of patients achieving educational levels at or beyond the level of the population as a whole and with the majority of patients able to support themselves. Future research may provide tools for even better assessment of this and other areas of psychosocial function.

Adaptation, Psychological↗
PubMed1984

Course of treated juvenile dermatomyositis.

Sixty-six patients with possible juvenile dermatomyositis (JDMS) were observed at the Children's Hospital of Los Angeles from 1960 to 1982. In patients initially given high doses of corticosteroids followed by low-dose therapy, three different clinical courses had previously been observed: monocyclic, polycyclic, and chronic continuous. We reviewed the records of 32 patients who met study criteria. The course of JDMS was monocyclic in eight children, chronic polycyclic in 10, and chronic continuous in 14. Of these children, 25 are well and not receiving medication; one has mild JDMS, without corticosteroid therapy; four have active JDMS despite corticosteroid therapy (one is severely handicapped); and two have died. Our results support the improved prognosis of JDMS after corticosteroid therapy, but also the great clinical variability of the disease. Understanding of this variability, as reflected in the three disease courses, facilitates physician choice of the optimal treatment with the least drug toxicity for the individual patient, continuing efforts to clarify the disease pathogenesis, and research efforts to improve current treatment programs for the patient with severe JDMS.

Acute Disease↗