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Biomedical subjects

P Ruiz

Publications and source records attributed to P Ruiz.

At least 145 records · Page 8Linked to original sources
PubMed1998

Diagnostic imaging of lipoma arborescens.

OBJECTIVE: The imaging characteristics of lipoma arborescens using plain radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) are described. DESIGN AND PATIENTS: Five patients with a diagnosis of lipoma arborescens are presented. Three had monoarticular involvement of the knee joint. In the remaining two patients both knees and both hips, respectively, were affected. All patients were examined using plain radiographs and MRI. CT was employed in two cases. RESULTS AND CONCLUSIONS: A conclusive diagnosis with exclusion of other synovial pathologies having similar clinical and radiological behavior can be achieved on the basis of the MRI characteristics of lipoma arborescens. The aetiology of lipoma arborescens remains unknown, but its association with previous pathology of the affected joints in all our patients supports the theory of a non-neoplastic reactive process involving the synovial membrane.

Adult↗
PubMed1998

Black and white patients response to antidepressant treatment for major depression.

Differences in response to psychopharmacologic agents according to race has so far primarily focused on investigations related to the response of Asian-American patients to neuroleptics and lithium. In this article, we present evidence which depicts that black patients need lower doses of tricyclic antidepressants (TCAs) than white patients to attain a similar response in the treatment of major depression. Likewise, we also advance that black patients might need lower doses of selective serotonin re-uptake inhibitor antidepressants (SSRIs) than white patients to attain a similar response in the treatment of major depression. Further studies are suggested to confirm these findings.

1-Naphthylamine↗
PubMed1998

Multicolor cytoenzymatic evaluation of dipeptidyl peptidase IV (CD26) function in normal and neoplastic human T-lymphocyte populations.

Dipeptidyl peptidase IV (DPP IV), also identified as the glycoprotein CD26, is a transmembrane 110- to 120-kDa serine aminopeptidase involved in immune responses by influencing T-cell costimulation and by cleaving cytokines. Additionally, CD26 is a nonintegrin receptor that contains a binding site for extracellular matrix and other molecules. In order to further define the expression and functional activity of this membrane exopeptidase in human T cells, we developed a nondisruptive, four-color cytofluorogenic assay that utilizes three separate antibodies to cell-surface molecules (e.g., CD4/CD8/CD26 and CD19/CD56/CD26) along with a rhodamine 110-conjugated dipeptide substrate that allows the measurement of DPP IV activity in phenotypically defined cells. We found normal human thymi to have notable differences in time-dependent DPP IV activity among the thymocyte subsets defined by their CD4/CD8 phenotype, with CD4-/CD8- thymocytes containing less DPP IV activity than cells expressing CD4 and/or CD8 (i.e., maturing). CD26 positivity was moderately intense in thymocytes and tended to identify cells with higher DPP IV activity. The four-color technique was also used to examine mature peripheral blood lymphocytes, along with an assortment of leukemias and transformed T-cell lines. These experiments revealed that while DPP IV was consistently evident in normal T cells, neoplastic T cells could vary in their expression patterns. Furthermore, the presence (or intensity) of surface CD26 in some abnormal T cells and certain normal peripheral blood mononuclear cells was separable from the level of DPP IV measured intracellularly. Our results established that multicolor cytofluorographic analysis can be a practical means to measure DPP IV activity in various human cell populations. Furthermore, we found that DPP IV activity could vary in T cells according to their differentiation status and that under certain circumstances surface CD26 expression can be disassociated from the level of measured enzyme (i.e., DPP IV) activity.

Cells, Cultured↗
PubMed1998

Adenovirus enterocolitis in human small bowel transplants.

This report describes two cases of pediatric small bowel transplant patients who developed diffuse adenovirus enterocolitis of their allografts. Based upon the presenting symptoms for this complication, in both patients a differential diagnosis of allograft rejection versus viral infection was clinically entertained. The clinical condition in both instances rapidly deteriorated and both patients died shortly after the development of the symptoms of fulminant septicemia. Autopsies were performed and histologic examination revealed extensive denudation of the gastrointestinal mucosa with edema and a marked acute and chronic inflammatory infiltrate involving the entire wall of the grafts. Numerous viral intranuclear and intracytoplasmic inclusions were evident and an immunohistochemical stain specific for adenovirus was strongly positive in the infected cells. In addition, while in the first case the adenovirus appeared confined to the GI tract, the second patient displayed numerous viral inclusions in the lung as well as within multiple liver abscesses. At this point, the incidence of adenovirus as a cause of gastroenteritis in small bowel transplant patients remains to be determined. We believe that the importance of recognizing this particular type of viral infection in this group of patients lies primarily in differentiating it from other viral organisms (e.g., CMV) that require a specific antiviral therapy. Moreover, an identification of this entity could help avoid a misdiagnosis of rejection which could lead to an unnecessary increase in immunosuppressive therapy and a possible exacerbation of the underlying condition.

Adenovirus Infections, Human↗
PubMed1997

Ritanserin in the treatment of cocaine dependence.

Sixty-five cocaine-dependent subjects were enrolled into a 10-week randomized, double-blind study to determine the safety and efficacy of the serotonin-2 receptor antagonist, ritanserin (10 mg/day), in reducing cocaine consumption and craving. All subjects also participated in a structured intensive outpatient psychosocial program. Seventy-three percent of the participants completed the treatment program and follow-up. Subjects experienced a significant reduction in craving: 66.4% and 32.5% for the placebo and ritanserin groups, respectively. These reductions in craving were not paralleled by substantial decreases in cocaine use. Self-reported cocaine use was less frequent in the placebo group; paradoxically, blood levels of its metabolite, benzoylecgonine, were also higher although insignificantly so. Generally, ritanserin was well tolerated but significantly prolonged the QTc interval on the electrocardiogram. This outpatient program is effective at maintaining cocaine-dependent individuals in treatment and reducing craving. Ritanserin (10 mg/day) is not an efficacious adjunct to psychosocial treatment for cocaine dependence.

Adult↗
PubMed1997

Successful living related liver transplantation in an adult with fulminant hepatic failure.

We report a case of an adult female who developed fulminant hepatic failure (FHF) during the second trimester of pregnancy and underwent a successful living related liver transplantation because no cadaveric donor was available during the development of life-threatening symptoms. A left lateral segment hepatic graft was procured from her brother, whose body weight was similar to hers. Her postoperative course was complicated by bleeding at the biliary anastomosis and subsequently by a biliary leak. Nevertheless, the complications were corrected surgically and the patient recovered well with a good quality of life 5 months after the transplant. This case suggests that living related liver transplantation should be considered more frequently for adult FHF patients. As the window of therapeutic opportunity is narrow for the dramatic condition of FHF, wide acceptance of this procedure will be of great benefit for the patients suffering from FHF.

Adult↗
PubMed1997

Clinical and serologic manifestations of autoimmune disease in MRL-lpr/lpr mice lacking nitric oxide synthase type 2.

Nitric oxide (NO) is an important mediator of the inflammatory response. MRL-lpr/lpr mice overexpress inducible nitric oxide synthase (NOS2) and overproduce NO in parallel with the development of an autoimmune syndrome with a variety of inflammatory manifestations. In previous studies, we showed that inhibiting NO production with the nonselective nitric oxide synthase (NOS) inhibitor NG-monomethyl-arginine reduced glomerulonephritis, arthritis, and vasculitis in MRL-lpr/lpr mice. To define further the role of NO and NOS2 in disease in MRL-lpr/lpr mice, mice with targeted disruption of NOS2 were produced by homologous recombination and bred to MRL-lpr/lpr mice to the N4 generation. MRL-lpr/lpr littermates homozygous for disrupted NOS2 (-/-), heterozygous for disrupted NOS2 (+/-), or wildtype (+/+) were derived for this study. Measures of NO production were markedly decreased in the MRL-lpr/lpr (-/-) mice compared with MRL-lpr/lpr (+/+) mice, with intermediate production by the MRL-lpr/lpr (+/-) mice. There was no detectable NOS2 protein by immunoblot analysis of the spleen, liver, kidney, and peritoneal macrophages of the (-/-) animals, whereas that of (+/+) was high and (+/-) intermediate. The (-/-) mice developed glomerular and synovial pathology similar to that of the (+/-) and (+/+) mice. However, (-/-) mice and (+/-) mice had significantly less vasculitis of medium-sized renal vessels than (+/+) mice. IgG rheumatoid factor levels were significantly lower in the (-/-) mice as compared with (+/+) mice, but levels of anti-DNA antibodies were comparable in all groups. Our findings show that NO derived from NOS2 has a variable impact on disease manifestations in MRL-lpr/lpr mice, suggesting heterogeneity in disease mechanisms.

Animals↗
PubMed1997

Recurrent Crohn's disease in transplanted bowel.

BACKGROUND: Intestinal transplantation is used in patients with short-bowel syndrome after repeated resections for Crohn's disease. We report the apparent clinical recurrence of Crohn's disease in a transplanted intestine. METHODS AND FINDINGS: The patient, a 33-year-old Hispanic woman, underwent small-bowel transplantation in December, 1994. Immunosuppression with tacrolimus, methylprednisolone, bone-marrow infusions, and OKT3 was given. In July, 1995, the patient had recurrent abdominal symptoms. The histological diagnosis of Crohn's disease was established by the independent interpretations of four experienced gastrointestinal histopathologists. INTERPRETATION: The prompt appearance of this autoimmune disorder (within 6 months of transplantation), despite massive immunosuppression may provide important insights into the nature of Crohn's disease and of the recurrence of autoimmune disease during immunosuppression.

Adult↗
PubMed1997

High-dose donor bone marrow infusions to enhance allograft survival: the effect of timing.

BACKGROUND: The development of strategies to enhance survival of transplanted organs and to potentially lower or even discontinue immunosuppressive therapy would represent a significant advance in posttransplant patient care. The aim of this clinical trial was to determine the effect of timing and dose of peripheral donor bone marrow cell (DBMC) infusion on graft and patient survival after liver transplantation. METHODS: DBMC, obtained from vertebral bodies, were administered in 101 recipients of liver allografts (OLTX). There were 107 patients for whom DBMC could not be obtained; they received OLTX alone (controls). A total of 5 x 10(8)/kg DBMC were infused at day 0 (group 1; n=9); at days 0 and 11 (group 2; n=26); or at days 5 and 11 (group 3; n=26). In group 4 (n=40), patients received up to five infusions of 2 x 10(8)/kg DBMC at days 5, 14, 21, 28, and 90 after OLTX. RESULTS: When the results from patients receiving two or more DBMC infusions (groups 2, 3, and 4) are considered, both patient and graft survival were significantly improved compared with the control group (P=0.02 and P=0.01, respectively). In groups 3 and 4, 88.5% and 95% of patients were alive with mean follow-up of 536 and 265 days, respectively, compared with 77.6% of patients in the control group (average follow-up of 452 days) (P=0.02). Graft survival was also significantly improved in groups 3 (88.5%) and 4 (92.5%), compared with the controls (72%) (P=0.007). CONCLUSIONS: The results suggest that dose and timing of DBMC infusions may be important variables affecting allograft survival. A randomized prospective trial is now in progress to compare group 3 DBMC infusion protocol with controls receiving OLTX alone.

Adult↗
PubMed1997

'Domino' liver transplantation combined with multivisceral transplantation.

Transplantation of the liver contemporaneously with another organ from the same donor is thought to confer an immunologic advantage. The latter is particularly desirable in intestinal transplantation because of the propensity of the intestinal graft to early and late rejections and because in some cases it may facilitate the operation. In clinical practice, shortage of liver grafts constrains liver transplantation to cases in which there is coexisting end stage liver disease.

Adolescent↗
PubMed1997

Effect of late modulation of nitric oxide production on murine lupus.

MRL/MpJ-Faslpr (MRL-lpr) and New Zealand Black/ White (NZB/W) mice develop spontaneous autoimmune disease characterized by autoantibody production and glomerulonephritis that progresses in parallel with increasing systemic nitric oxide (NO) production. A previously published study from our laboratory indicated that oral administration of the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (NMMA) before the onset of clinical disease significantly decreased renal and joint pathology in MRL-lpr mice. To characterize the effect of late modulation of NO production in murine SLE, we administered oral NMMA and/or restricted dietary arginine after disease onset in two murine models of SLE. When receiving combined NMMA and arginine restriction, MRL-lpr mice had reduced joint pathology scores and NZB/W mice had lower renal pathology scores than control mice. These results indicate that modulating NO production after the onset of disease diminishes disease severity in two models of SLE, although not as effectively as treating before disease onset.

Animals↗
PubMed1997

Diagnosis of intraocular lymphoma by flow cytometry.

PURPOSE: To evaluate flow cytometry of vitreous cellular specimens as a means of diagnosing intraocular lymphoma and ocular inflammatory disease. METHODS: We undertook a retrospective, observational study of hematopoietic cell-surface markers in 20 patients with vitreous cellular infiltration in whom lymphoma was considered in the differential diagnosis. Immunophenotyping of vitreous cells obtained by vitrectomy was performed by flow cytometry using antibodies directed against specific cell-surface antigens, including ones associated with B-lymphocyte and T-lymphocyte lymphomas and activated inflammatory cells. Smears were examined cytologically. Cytofluorography was compared with the cytopathologic diagnosis and with final diagnosis. RESULTS: With flow cytometry, a diagnosis of intraocular lymphoma was confirmed in two of four patients with known lymphoma, one of whom had recurrent disease after radiation, and not confirmed in two patients who had had prior treatment with radiation or corticosteroids. In six patients with no prior diagnosis of lymphoma, five were diagnosed with lymphoma on the basis of cytofluorography. Thus, seven (70%) of 10 patients with intraocular lymphoma were diagnosed by cytofluorography compared with three (30%) of 10 with lymphoma diagnosed by cytology. With flow cytometry, 10 patients with uveitis or intraocular infections were distinguishable from patients with lymphoma by lack of a monotypic population and, in some cases, by elevated CD4:CD8 ratios and a high percentage of activated cells. CONCLUSIONS: Cytofluorography of vitreous cells is an effective alternative or adjunct to cytology. Information can be gained from specimens that are uninterpretable by routine cytology. The optimal technique for diagnosis may vary among institutions.

Adult↗
PubMed1997

Dipeptidyl peptidase IV (CD26) activity in human alloreactive T cell subsets varies with the stage of differentiation and activation status.

Dipeptidyl peptidase IV (DPP IV), also known as CD26, is a transmembrane serine aminopeptidase which has an ontogenically related expression on T cells and participates on several immunological functions. CD26 appears to play an important role in alloimmunity during host T cell activation subsequent to alloantigen encounter and is a way by which effector T cells traverse graft endothelial barriers. In order to help to elucidate the role of the CD26 molecule in alloimmune responses, DPP IV activity and CD26 antigenic expression were assessed during the initial phases of completely MHC-disparate human mixed lymphocyte reactions (MLRs) and in several long-term alloreactive T cell clones. Our methods involved the use of a rhodamine-110-conjugated dipeptide substrate specific for DPP IV in two-colour cytofluorographic analysis that allowed stimultaneous lineage marker evaluation. Polyclonal populations of alloreactive CD4 and CD8 T cells contained DPP IV activity at 1 and 10 min of incubation that was variably elevated from resting T cells with the enzyme activity confined to CD26+ cells. T cell clones derived from MLRs were established with IL-2 supplementation and alloantigen restimulation and had reduced CD62L expression with functional specificity to the stimulating MHC. While CD26 expression remained stable, DPP IV activity was variable in the alloreactive T cell clones, with enzyme function in the latter appearing to coincide with the timing of alloantigen restimulation. These studies demonstrate that DPP IV activity varies among phenotypically distinct alloreactive T cell subsets and appears to be altered with the activation status of the effector cells. These findings raise the potential of a role for CD26/DPP IV in the generation of specific alloimmunity. With this methodology, it may be possible to reveal whether specific alterations in the activity of this molecule in T cell populations promote graft acceptance and to determine the molecular requirements for these changes.

CD4-Positive T-Lymphocytes↗