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C Rosales

Publications and source records attributed to C Rosales.

36 records · Page 2Linked to original sources
PubMed1992

Calcium channel blockers nifedipine and diltiazem inhibit Ca2+ release from intracellular stores in neutrophils.

We have undertaken a detailed study of the mechanisms of maintenance of intracellular Ca2+ homeostasis in human polymorphonuclear neutrophils (PMN) and its implications for phagocytosis and IgG Fc receptor (FcR) signaling. When PMN were incubated in Ca(2+)-free medium, cytoplasmic calcium concentration ([Ca2+]i) was markedly depressed and intracellular stores were depleted of calcium. [Ca2+]i in these depleted cells increased within 1 min when PMN were placed in medium containing Ca2+ and then decreased to a level close to the normal basal [Ca2+]i, replenishing the intracellular Ca2+ pools. LaCl3 prevented entry of Ca2+ into Ca(2+)-depleted PMN, but the calcium channel blockers nifedipine, diltiazem, and verapamil did not. Nifedipine and diltiazem but not verapamil inhibited the movement of Ca2+ from cytosol to intracellular stores. Nifedipine and diltiazem inhibited the normal increase in [Ca2+]i from aggregated IgG binding to FcR and also prevented formyl-methionyl-leucyl-phenyl-alanine (fMLP)-induced [Ca2+]i rise. Verapamil had no effect on either an fMLP- or IgG-mediated increase in [Ca2+]i. Consistent with this, nifedipine and diltiazem inhibited fMLP-stimulated phagocytosis (which is dependent on an increase in [Ca2+]i) when PMN had repleted intracellular stores. In contrast, LaCl3 inhibited fMLP-stimulated ingestion only in PMN which had intracellular store depleted. None of these compounds had any effect on phorbol dibutyrate-stimulated ingestion (which is independent of a [Ca2+]i rise). In summary, these data show that Ca2+ is in rapid equilibrium between intracellular and extracellular compartments in PMN. Exchange of cytoplasmic Ca2+ with the extracellular space is inhibited by LaCl3, while exchange of Ca2+ between the cytosol and intracellular stores is inhibited by the dihydropyridine nifedipine and the benzothiazepine diltiazem. These data suggest that these drugs, which are known to regulate some plasma membrane Ca2+ channels in excitable cells, can also regulate Ca2+ release from intracellular stores in PMN and that this regulation may have significant effects on PMN function.

Adult↗
PubMed1992

Human leukocyte A and B antigen, gene and haplotype frequencies in the population of the city of São Paulo in Brazil.

1. Antigen, gene and haplotype frequencies are important data for population analysis, paternity exclusion testing, genetic studies, and for organ transplantation selection. 2. We have studied the Class I histocompatibility antigens of 617 unrelated individuals from the city of São Paulo, Brazil, to determine antigen and gene frequencies of 16 HLA-A and 28 HLA-B antigens. Estimated haplotype frequencies were also determined, as well as the genetic distances of this population from European Caucasian and Negro populations. 3. A previously unknown linkage disequilibrium was detected for A23-B49 and a clear trend towards antigen frequencies intermediate between Caucasoid and Negro populations was observed.

Adult↗
PubMed1991

Two mechanisms for IgG Fc-receptor-mediated phagocytosis by human neutrophils.

Neutrophils (PMN) stimulated with the chemo-attractant FMLP, with platelet activating factor (PAF), and with phorbol dibutyrate exhibited a three- to fivefold increase in phagocytosis of IgG-opsonized sheep E (ElgG). Enhancement of phagocytosis occurred even when stimulants were washed away before the ElgG were added, showing that they could prime PMN for enhanced phagocytosis. When PMN were loaded with MAPTAM, a cell permeant analog of EGTA that prevented any rise in [Ca2+]i, they showed no FMLP-stimulated phagocytosis but had a normal phagocytic response to PAF and phorbol dibutyrate. Addition of MAPTAM after FMLP priming abolished enhanced ingestion, even in the presence of optimal extracellular Ca2+. Thus, the [Ca2+]i rise that occurred on ligation of PMN IgG FcR by ElgG was required for FMLP-stimulated phagocytosis. We determined which FcR were involved in this [Ca2+]i rise and in FMLP-stimulated phagocytosis. Aggregated (agg-IgG) IgG and the anti FcRIII mAb 3G8 both caused increases in [Ca2+]i, removal of FcRIII with phosphatidylinositol-specific phospholipase C (PIPLC) abolished the 3G8-dependent rise in [Ca2+]i without affecting the agg-IgG-dependent rise. Moreover, IV.3 (anti FcRII mAb) completely inhibited the agg-IgG-induced increase in [Ca2+]i in PIPLC-treated PMN, showing that ligation of FcRII is sufficient for a normal IgG-induced [Ca2+]i rise. FMLP-stimulated phagocytosis also was unaffected by PIPLC, suggesting that the rise in [Ca2+]i required for FMLP-stimulated phagocytosis could come from FcRII ligation. From these studies we conclude that there are two molecular mechanisms for IgG-mediated phagocytosis in activated PMN. One, stimulated by FMLP, is dependent on an increase of intracellular Ca2+ during the ingestion process; the other, activated by phorbol esters and PAF, is capable of effecting high levels of ingestion at very low concentrations of [Ca2+]i. These data are consistent with the hypothesis that ligation of FcRII by IgG opsonized targets is sufficient for this Ca(2+)-dependent mechanism of stimulated phagocytosis.

Calcium↗
PubMed1991

The use of absorbable staples for construction of a bladder tube.

Stapling instruments have been widely used in general surgery but not in the surgical treatment of the urinary tract. The stapler Poly CS-57 (Auto Suture, U. S. S. C.) with absorbable staples has been evaluated in the construction of ten bladder tubes for ureteral substitution in three dogs and six pigs. The dogs and pigs were sacrificed at two, three and six months. There was no mortality rate, no infections, no suture leakages and no crystal or stone formation. There were three instances of ureterovesical anastomotic stenosis. It appears that the absorbable staple can be safely used in urologic operations and that the use of the Poly CS 57 stapler for the construction of a bladder tube makes the procedure safer, simpler and faster.

Absorption↗
PubMed1988

Cytolytic activity of murine anti-dog lymphoma monoclonal antibodies with canine effector cells and complement.

Peripheral blood leukocytes (PBL), nonadherent lymphocytes, and adherent monocytes separated from freshly isolated blood of 15 dogs were analyzed for their ability to mediate antibody-dependent cell-mediated cytotoxicity (ADCC) in combination with murine anti-tumor monoclonal antibodies (MAbs). Canine monocytes isolated from most donors by adherence to gelatin-fibronectin-coated plastic surface presented high ADCC activity against the canine lymphoma 17-71 tumor cell line in combination with antilymphoma MAbs 231 (IgG2a) and 234-2a (IgG2a). Canine lymphocytes generally showed lower ADCC activity than total PBL or monocytes. Canine PBL effector cells showed high ADCC activity against the human colorectal carcinoma SW948 cell line using the Y-6-specific MAb isotype switch variants 55-2 IgG3, 55-2 IgG1, 55-2 IgG2b, and 55-2 IgG2a. Analysis of the role of murine MAb isotypes on ADCC activity against tumors by canine cells using anti-human tumor class-switch variant MAbs and a panel of anti-canine lymphoma MAbs of different IgG subclass revealed the highest ADCC activity with MAbs of the IgG2a and IgG3 subclasses. IgG2a antilymphoma MAbs were also able to lyse tumor cells in complement-dependent cytotoxicity (CDC) assay. These results suggest the potential value of MAbs of IgG3 and IgG2a subclasses in immunotherapy against canine lymphoma.

Animals↗
PubMed1988

Detection thresholds of nonocclusive intestinal hypoperfusion by Doppler ultrasound, photoplethysmography, and fluorescein.

Because clinical assessment of bowel viability is unreliable, other methods of determining intestinal perfusion have been recommended. Since none of these quantifies intestinal blood flow, we measured flow at the detection thresholds of Doppler ultrasound, photoplethysmography, and intravenously administered fluorescein, perfused the intestines at these threshold levels, and assessed histologic evidence of ischemic damage. The intestines of five anesthetized dogs were perfused for 4 hours via an in-line pulsatile extra-corporeal circuit assembled between the iliac and superior mesenteric arteries at either relatively physiologic (approximately 20 ml/min/kg body weight) levels or reduced levels representing the flow detection thresholds of Doppler ultrasound or photoplethysmographic probes (approximately 4 ml/min/kg). Intravenously administered fluorescein was detected at even lower perfusion levels (approximately 2.1 ml/min/kg). Clear-cut ischemic changes were documented histologically in all subjects perfused at Doppler/PPG flow detection thresholds but in none of those perfused at normal levels. We conclude that threshold blood flow detection by any one of these methods, especially fluorescein, occurs at levels inadequate to guarantee tissue viability.

Animals↗
PubMed1987

Sympathectomy for causalgia. Patient selection and long-term results.

Thirty-four sympathectomies were performed for causalgic pain. Overt extremity trauma was the precipitating event in only 26%. In 48%, nerve compression requiring surgical relief preceded the onset of the pain; most common lumbar disk surgery (37%). In the remainder (26%), miscellaneous vascular conditions contributed. Satisfactory immediate relief was obtained in 97% and 61% were completely relieved of pain initially. There were no deaths, 10% wound complication rate, and one instance of Horner's syndrome. Postsympathectomy neuralgia occurred in close to 40%, lasted a little over a month on the average but did not persist beyond ten weeks. In extended follow-up, only one patient failed to sustain satisfactory relief (97% of those relieved, 94% of the total) and 84% continued to enjoy the same degree of relief as they had immediately preoperatively. This frequency, degree, and duration of benefit establishes causalgic pain as one of the best indications for surgical sympathectomy.

Adolescent↗
PubMed1987

Canine lymphoma-associated antigens defined by murine monoclonal antibodies.

Lymphoma in dogs resembles human non-Hodgkin's lymphoma in pathological presentation, immunophenotype, and response to therapy, thus representing a good model for comparative studies with human disease. Monoclonal antibodies (MAbs) were derived from mice immunized with a dog lymphoma cell line. Three MAbs were selected for further application in immunophenotyping and immunotherapy. The binding specificities, antigen characterization, and isotypes for these MAbs are described.

Animals↗
PubMedDate not supplied

In vivo destruction of canine lymphoma mediated by murine monoclonal antibodies.

The effect of murine anti-canine lymphoma monoclonal antibodies (MAbs) on tumor cell lysis by thioglycolate activated murine macrophages in vitro and tumor growth inhibition in athymic mice was studied. All IgG1 and IgG2a MAbs tested were able to promote specific destruction of canine lymphoma 17-71 cell line by activated macrophages. A correlation between higher ADCC activity and MAb isotype was not clearly evident. In vivo IgG2a and IgG1 MAbs inhibited the growth of canine lymphoma. These results suggest that MAbs of IgG type have potential in immunotherapy of dogs with lymphoma since they have high tumoricidal activity in vivo.

Animals↗