Biomedical subjects

J Wilkins

Publications and source records attributed to J Wilkins.

At least 55 records · Page 3Linked to original sources

PubMed1994

Adhesion of peripheral blood lymphocytes of children with arthritis to human umbilical vein endothelial cells.

To determine whether adhesion of peripheral blood lymphocytes (PBL) of patients with juvenile rheumatoid arthritis (JRA) may be enhanced, adhesion of PBL of children with JRA, children with seronegative spondyloarthropathies (SSA), age-appropriate and adult controls, to human umbilical vein endothelial cells (HUVEC) was assessed in vitro. B and CD4 T lymphocytes in initial, adherent, and non-adherent cell fraction were identified by flow cytometry. B lymphocytes of all the younger subjects combined had a higher adherence to activated HUVEC compared with B lymphocytes of the adult donors. Except for greater adherence of HLA-DR+ CD4 T cells, lymphocytes of children with JRA showed no enhanced adhesion to either unactivated or activated HUVEC. The percentage of B cells adherent to activated HUVEC in each of the subject groups was 1.5-3.6-fold higher than adherent CD4 T lymphocytes. Surface analyses indicated higher percentages of CD49d (alpha 4)+ and CD29 (beta 1)+ CD4 T lymphocytes in adherent cells, but less of a differential in CD49 (alpha 4)+ and no difference in CD29 (beta 1)+ B lymphocytes. There were fewer Leu-8 (L-selectin)+ B and Leu-8+ CD4 T cells among adherent cells. The data suggest a greater adhesive capacity of B lymphocytes compared with CD4 T lymphocytes which is unrelated to disease, and the possibility that B lymphocytes may utilize adhesion molecules distinct from those of CD4 T lymphocytes. Only a small subset of T cells of patients with JRA may have an enhanced capacity for adhesion to endothelium.

Adolescent↗

PubMed1994

Comparison of the results of bacterial cultures from multiple sites in chronic osteomyelitis of long bones. A prospective study.

We evaluated the results of aerobic, anaerobic, and fungal cultures of specimens that had been obtained from multiple sites in thirty patients who had traumatic osteomyelitis with a sinus track. In each patient, we obtained specimens of material from the sinus track; specimens of purulent fluid, of soft tissue, and of bone obtained from curettage; and specimens from the bed of the involved bone. More than one organism grew on culture of the specimens from twenty-one of the patients; more than three organisms, from those of eleven patients; and ten organisms, from those of two patients. The same organisms grew on culture of the specimens from every site in only fourteen (47 per cent) of the thirty patients. We recommend that specimens of material from the sinus track; specimens of purulent material, of soft tissue, and of bone obtained from curettage; and specimens from the bed of the involved bone be obtained for culture before the treatment of chronic osteomyelitis with a draining sinus, so that as many of the infecting organisms as possible will be identified.

Bacteria, Aerobic↗

PubMed1994

Involvement of beta-1 and beta-2 adrenergic receptors in the antidepressant-like effects of centrally administered isoproterenol.

Central (i.c.v.) but not peripheral (i.p.) administration of isoproterenol reduced response rates and increased reinforcement rates of rats under a differential-reinforcement-of-low-response-rate 72-sec schedule in a dose-dependent manner. This effect of centrally administered isoproterenol was similar to effects produced by administration of proven antidepressant drugs. Propranolol antagonized the effect of centrally administered isoproterenol, suggesting that the antidepressant-like effect of this agonist was mediated by beta adrenergic receptors. In addition, both the beta-1 selective antagonist betaxolol and the beta-2 selective antagonist ICI 118,551 antagonized the effect of centrally administered isoproterenol in a dose-dependent manner. These antagonists exhibited similar potency, suggesting that both beta-1 and beta-2 adrenergic receptors were involved in the mediation of the antidepressant-like effect of centrally administered isoproterenol. In rats with down-regulated beta-2 adrenergic receptors, produced by repeated treatment with clenbuterol, isoproterenol still reduced response rates and increased reinforcement rates of rats under the differential-reinforcement-of-low-response-rate schedule. By contrast, the antidepressant-like effect of the beta-2 adrenergic agonist clenbuterol was attenuated by down-regulation of beta-2 adrenergic receptors. The present results indicate that stimulation of central beta adrenergic receptors by intraventricular administration of isoproterenol produces behavioral changes similar to those observed after administration of proven antidepressant drugs. Both beta-1 and beta-2 adrenergic receptors appear to mediate the antidepressant-like effect of isoproterenol.

Animals↗

PubMed1994

Cell attachment to extracellular matrix substrates is inhibited upon downregulation of expression of calreticulin, an intracellular integrin alpha-subunit-binding protein.

We have demonstrated recently that calreticulin, an intracellular calcium-binding protein, can interact with the alpha-subunits of integrin receptors via the highly conserved KXGFFKR amino acid sequence present in the cytoplasmic domains of all integrin alpha-subunits (Rojiani et al. (1991) Biochemistry 30, 9859-9866). Here we demonstrate that calreticulin can be co-localized by immunofluorescence as well as co-purified with integrins, that recombinant calreticulin can also interact with integrins, and that the interaction occurs predominantly via the N-domain of calreticulin, to a much lesser extent with the C-domain, but not at all with the proline-rich P-domain. To demonstrate a physiological role for the interaction of calreticulin with integrins, calreticulin expression was downregulated by treating cells with antisense oligonucleotides designed to inhibit the initiation of translation of calreticulin. Antisense oligonucleotides, but not sense or non-sense oligonucleotides, inhibited attachment and spreading of cells cultured in the presence of fetal bovine serum, and also of cells plated on individual extracellular matrix substrates in the absence of serum. The antisense oligonucleotide inhibited cell proliferation of anchorage-dependent cells slightly, but there was no effect on cell viability. The effect on cell attachment was similar to that achieved by treating cells with an antisense oligonucleotide designed to inhibit translation of the integrin alpha 3 subunit, which resulted in the inhibition of cell attachment to alpha 3 beta 1-specific substrates. The effect of the antisense calreticulin oligonucleotide on cell attachment was demonstrated to be integrin-mediated since antisense calreticulin treatment of Jurkat cells abrogated the stimulation of collagen cell attachment achieved by attachment-stimulating signalling anti-alpha 2 (JBS2) and anti-beta 1 (21C8) antibodies. The oligonucleotides did not affect the rate of cell proliferation of these cells. These results demonstrate a fundamental role of calreticulin in cell-extracellular matrix interactions.

Amino Acid Sequence↗

PubMed1994

Rapid automated enzyme immunoassay of serum amyloid A.

Serum amyloid A (SAA), a sensitive acute-phase protein, is the precursor of AA fibrils in reactive amyloidosis. However, SAA is poorly immunogenic, and development and standardization of immunoassays of this protein have been difficult. We established an automated polyclonal/monoclonal microparticle capture enzyme immunoassay, standardized with the World Health Organization prospective reference standard for SAA. A stabilized concentrate of SAA was used for controls and calibrators. The assay range was 1-750 mg/L with CVs < 7% throughout. Plasma and serum gave identical results and no interferences were observed. Linear regression against radial immunodiffusion assay gave a slope of 1.04 (95% confidence interval 0.99-1.10), intercept of -9 mg/L (95% confidence interval -14-3), and residual SD (SEE) of 20 for samples containing < or = 200 mg/L (n = 173). In 105 apparently healthy adults the mean (SD) SAA concentration was 3.7 (3.6) mg/L, the median was 3.0 mg/L, and the range, 0.7-26.4 mg/L. In clinical acute-phase sera, values up to 2200 mg/L were seen. This method will facilitate measurement and investigation of SAA in clinical practice generally and in AA amyloidosis.

Acute-Phase Reaction↗

PubMed1993

Stimulation of tyrosine phosphorylation and accumulation of GTP-bound p21ras upon antibody-mediated alpha 2 beta 1 integrin activation in T-lymphoblastic cells.

Integrins are a family of heterodimeric integral plasma membrane proteins that behave as receptors for components of the extracellular matrix and also mediate cell to cell adhesion. Occupation of integrins can result in the transduction of intracellular signals, leading to cytoskeletal reorganization, tyrosine phosphorylation, and induction of gene expression. We report here that the ligation of alpha 2 beta 1 integrin by collagen-adhesion stimulatory anti-alpha 2 and anti-beta 1 antibodies resulted in the accumulation of p21ras in the active GTP-bound state in Jurkat T-lymphoblastoid cells. The activation was accompanied by the tyrosine phosphorylation of proteins of 47-52 kDa. This stimulation of tyrosine phosphorylation and p21ras activation was specific for the activating antibodies and occurred within 2 min of the addition of these antibodies. Although treatment of the cells with the protein kinase C activator, phorbol 12-myristate 13-acetate also resulted in an induction of both cell attachment to collagen and of p21ras activation, tyrosine phosphorylation was not observed. These results demonstrate that alpha 2 beta 1 integrin activation can result in the specific stimulation of tyrosine phosphorylation of 47-52-kDa proteins, as well as activation of a signaling pathway involving p21ras.

Antibodies↗

PubMed1993

Lymphocyte-synovial cell interactions: a role for beta 1 and beta 3 integrin-mediated adhesion to cellular fibronectin.

The interactions of lymphocytes with cultured synovial cells derived from rheumatoid arthritis patients were examined. A number of lymphoid cell lines bound to these cells. The adherence of several of these lines was inhibited by antibodies to fibronectin. The adherence of the T cell leukemia Jurkat was sensitive to inhibition by antibodies to the fibronectin receptors alpha 4 beta 1 and alpha 5 beta 1. The adherence of the beta 1 integrin negative B cell line RPMI 8866 was inhibited by antibodies to the vitronectin receptor, alpha v beta 3. The interactions of several other cell lines with synovial cells appeared to be independent of this fibronectin-dependent pathway. These results indicate that multiple potential adhesion pathways for cellular interactions in the tissues may exist. The adherence to cell-associated fibronectin may play a contributory role in such processes for certain lymphocyte subsets.

Cell Adhesion↗

PubMed1993

Urinary immunoreactive interleukin-1 alpha and interleukin-6 in bacteriuric institutionalized elderly subjects.

Urinary immunoreactive interleukin-1 alpha and interleukin-6 levels were measured in specimens obtained from elderly institutionalized subjects, including 67 asymptomatic subjects (51 of whom were bacteriuric), 34 with fever from nonurinary sources, 15 with bacteriuria and 9 with symptomatic urinary infection. For bacteriuric subjects urinary interleukin-1 alpha and interleukin-6 levels were measurable in 18 (35%) and 22 (43%) asymptomatic subjects, respectively, 9 (60%) and 8 (53%) with nonurinary sources of fever, respectively, and 6 (67%) and 7 (78%) with urinary infection, respectively. For subjects without bacteriuria 1 of 16 (6.3%) who were asymptomatic and 5 (25%) with nonurinary sources of fever had measurable urinary interleukin-1 alpha, and 2 (13%) and 1 (5.3%), respectively, had measurable interleukin-6. Presence of interleukin-1 alpha or interleukin-6 was significantly associated with bacteriuria for asymptomatic and symptomatic subjects. Interleukin-1 alpha or interleukin-6 quantitative levels were lower in subjects without than with bacteriuria. Quantitative levels of interleukin-6 tended to decrease for bacteriuric subjects with symptomatic infection between acute and convalescent specimens. These observations suggest that interleukin-1 alpha and interleukin-6 are produced in association with bacteriuria in some elderly subjects. Variation in local cytokine production with time and the clinical significance of these observations require further study.

Age Factors↗

PubMed1993

Unrecognized cocaine use among schizophrenic patients.

OBJECTIVE: Unrecognized stimulant use could lead to the misdiagnosis of schizophrenia or the misunderstanding of its course and prognosis. This study was conducted to determine the prevalence of unrecognized stimulant use among patients with a clinical diagnosis of schizophrenia. METHOD: The subjects were 108 schizophrenic patients admitted consecutively to a Veterans Affairs psychiatric hospital. Admitting psychiatrists supplemented routine clinical evaluations with a semistructured interview regarding recent and lifetime use of alcohol, cocaine, amphetamine, marijuana, and opiates. A urine specimen was assayed for the four illicit drugs. RESULTS: Of the 103 patients who provided a urine specimen, 37 (36%) used cocaine during the 6 months before admission, including 31 who used the drug in the week before admission. Because of the poor reliability of negative self-reports of recent cocaine use, clinicians failed to recognize cocaine use in one-third of the patients with a urine toxicology positive for cocaine metabolites. Two other groups of patients were identified; schizophrenic patients without substance abuse (including alcohol) and schizophrenic patients with substance abuse other than stimulants. Both substance-abusing groups were younger than the nonabusing group, but the three groups had similarly high rates of recent psychotic symptoms, homelessness, and unemployment. CONCLUSIONS: Among schizophrenic patients who require hospitalization, clinicians should not rely solely on self-reported stimulant use. Recognition of stimulant use could be improved through routine urine toxicologies for all psychotic patients. The authors suggest that recognition of stimulant use among schizophrenic patients may identify a population with a better prognosis for schizophrenia and different treatment needs.

Adult↗

PubMed1993

Lymphocyte emperipolesis in human glial cells.

Astrocytes have been observed to contain intact, viable lymphocytes within their cytoplasm (emperipolesis) in multiple sclerosis plaques and some brain tumors. This study characterizes the adhesive, emperipoletic and phagocytic properties of glial cells in culture. Human fetal and adult astrocytes engaged in adhesion and emperipolesis of lymphocytes. Emperipolesis, and not adhesion, was temperature- and cation-dependent. The CD8 and MHC Class I antigens played a role in emperipolesis. Lymphocytes most often remained viable within the cytoplasm of astrocytes but occasionally underwent lysis or caused disruption of the astrocyte intermediate filaments. The phenomenon of emperipolesis is distinct from phagocytosis, since microglia showed prominent phagocytic properties but did not engage in emperipolesis. Conversely, astrocytes were efficient emperipolites and rarely demonstrated phagocytic properties.

Astrocytes↗

PubMed1993

Beta 1 (CD29) integrin expression in rheumatoid synovial membranes: an immunohistologic study of distribution patterns.

Cellular attachment to, and migration into, tissues are critical aspects of the inflammatory process. Our studies were undertaken to examine the distribution of one of the families of adhesion molecules, the beta 1 integrins (VLA antigens), in inflamed rheumatoid synovial tissues. The distribution of lymphocyte subsets and the beta 1 integrins (beta 1, VLA-1, 2, 3, 4, 5) were studied in 10 rheumatoid synovial membranes using immunohistochemistry and monoclonal antibodies. The majority of lymphocytes stained positively for beta 1, VLA-3, VLA-4 and VLA-5. Intravascular mononuclear cells adherent to the endothelium appeared to generally express low levels of beta 1 when compared to those in the extravascular space, suggesting that lymphocytes may augment their expression of this molecule subsequent to their extravasation into the tissue. Cells in the synovial lining layer expressed beta 1, VLA-1, VLA-3 and and VLA-5. The endothelium of the synovial vasculature stained intensely for beta 1, VLA-1, VLA-3 and VLA-5 with more limited staining for VLA-2. The venules and capillaries in and around the subsynovial lymphocytic aggregates demonstrated the most intense vascular staining. We conclude that the beta 1 integrins are expressed by a variety of cells in the rheumatoid synovial membrane. The expression of beta 1 integrins may be subject to regulation by the inflammatory microenvironment thus contributing to a more adhesive environment into which inflammatory cells are more readily recruited and retained.

Antibodies, Monoclonal↗

PubMed1993

Treatment of chronic osteomyelitis with muscle flaps.

This article discusses a study of 36 patients with chronic osteomyelitis that had local or free muscle flaps. Reconstruction of chronic osteomyelitis requires infection control and assessment of soft tissue and bone. In patients with osteomyelitis with an ununited fracture or nonunion, stabilization of the fracture is needed.

Adult↗

PubMed1993

Septopal beads and autogenous bone grafting for bone defects in patients with chronic osteomyelitis.

Thirty-five patients with chronic osteomyelitis were treated with autogenous bone grafts for bone defects. Of 35 patients, two were lost to follow-up evaluation. There were 27 men and six women. The age range was from 18 to 62 years (median age, 29 years). The bones included 22 tibias, nine femurs, and two ulnas. The size of the bone defects ranged from 2.5 x 15 cm (median defect, 2.5 x 6 cm). The length of infection ranged from two to 540 months (median, 31 months). Twenty patients had nonunions and 19 patients required soft-tissue muscle transfers. Patients were treated with systemic antibiotics and/or gentamicin (Septopal) antibiotic beads. Twelve patients were treated with Septopal beads. The range of follow-up evaluation was 24 to 68 months (median, 47 months). Thirty-one of 33 patients had one bone-graft procedure and two patients required two. The time from initial debridement and infection control to bone graft for patients not requiring soft-tissue muscle flaps was one to six weeks (median time, four weeks). For patients requiring soft-tissue muscle transfer, the range was six to nine weeks (median, six weeks). The median time to bone-graft incorporation was six months. All fractures united. Complications included two refractures from auto accidents in the immediate postoperative period, one partial muscle loss, one skin-graft loss, four pin tract draining sites, and two antibiotic-related skin rashes. There was one recurrent infection, and the infection arrest rate was 97%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Comparison of the clinical efficacy and tolerance of gentamicin PMMA beads on surgical wire versus combined and systemic therapy for osteomyelitis.

These data do not prove a statistical superiority of conventional antibiotics or Septopal in the treatment of chronic osteomyelitis. This result, however, is complicated by the biased data set represented by the combined treatment. The data do suggest that cost of treatment is considerably less in patients who are treated with local antibiotics (i.e., Septopal) alone. The rate of adverse experiences was directly related to the use of parenteral antibiotics, with higher rates of adverse experiences in the conventional and combined treatment groups. Furthermore, the Cierny-Mader Physiologic Class had the best correlation with outcome, suggesting that host factors are probably of critical importance in inducing remission of chronic osteomyelitis. This protocol was not designed to test the role of debridement in the treatment of osteomyelitis: it was assumed that debridement would be the same in both groups. It is the investigators' strong opinion, however, that adequacy of debridement was an important determinant in quiescence or recurrence in the study patients. Similarly, there was no strict control for adequacy of soft-tissue coverage provided by local or distant tissue transfer. Again, the investigators believe that adequacy, including viability and durability, of soft-tissue covering was an important determinant for the end result in these patients. Other covariants such as smoking, history, nutritional status, and other measures of general health will be added to this model when data are available. This analysis will allow definition of the appropriate clinical situations in which use of Septopal alone or combined with parenteral antibiotic is indicated.

Anti-Bacterial Agents↗

PubMed1992

The interactions of gamma delta T cells with extracellular matrix: receptor expression and utilization patterns.

Purified populations and clones of human gamma delta T cells were examined for their ability to interact with extracellular matrix (ECM) components. The stimulation of these cells with phorbol ester induced cellular adhesion for ECM. The adhesion structures for fibronectin and collagen were shown to be members of the CD29 integrin family. The expression patterns of beta 1, beta 2 and beta 3 integrins by these cells were examined. The receptor expression and utilization patterns suggest that alpha beta, gamma delta T cells and B cells have similar repertoires of adhesion structure.

Antigens, CD↗

PubMed1992

Oculocutaneous manifestations of the erythema multiforme/Stevens-Johnson syndrome/toxic epidermal necrolysis spectrum.

Although they were once believed to be distinct diseases, many observers currently consider erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis to represent a mild-to-severe continuum of the same process. Each shares certain clinical, histologic, and etiologic characteristics; among the latter two are frequent ocular involvement. Because long-term ophthalmic sequelae may be catastrophic, early recognition and therapy of this acute oculocutaneous disease spectrum are critically important.

Conjunctivitis↗

PubMed1991

Antibodies to different members of the beta 1 (CD29) integrins induce homotypic and heterotypic cellular aggregation.

Members of the beta 1 (CD29) integrin family are involved in cellular adhesion to extracellular matrix. However, there have been several reports of CD29 integrin participation in intercellular adhesion. For example, the treatment of the human T cell line Jurkat with antibodies to alpha 4 (CD49d) causes homotypic aggregation. The present report describes the induction of aggregation of Jurkat cells by antibodies to alpha 5 (CD49e) and to a lesser extent by antibodies to the common beta 1/CD29 chain of these integrins. The metabolic requirements for these aggregations are compared with that of the CD49d-induced process. The possible involvement of fibronectin in the cytoadhesion appears to be unlikely as (1) the aggregates form in the absence of plasma fibronectin; (2) antibodies to fibronectin do not inhibit the cell adhesion; and (3) exogenous fibronectin does not influence the process. One of the cognate partners involved in the CD49e-induced aggregation appears to be present on non-antibody-treated Jurkat cells as the cells are coincorporated into aggregates of anti-CD49e-stimulated cells. The adhesion does not appear to involve members of the CD2, CD3, CD4, or CD18 receptor groups. These results indicate that interaction with alpha 4, alpha 5 chain or the beta 1 chain of the CD29 integrins leads to the induction of intercellular adhesion. The possible biological significance of this process is discussed.

Animals↗

PubMed1991

A silicone pellet for continuous cocaine: comparison with continuous amphetamine.

An inexpensive silicone pellet is described for the continuous administration of cocaine for up to 5 days. Rats implanted with this pellet show minimal skin irritation and go through distinct behavioral stages, with an initial period of hyperactivity followed by motor stereotypies. Then, at 3-4 days after implantation, a variety of hallucinogen-like ("late-stage") behaviors appear, including limb flicks, sudden startle responses, and repetitive mid-air grasping movements. Compared to continuous d-amphetamine, continuous cocaine induces decreased motor stereotypies but heightened "late-stage" behaviors.

Animals↗