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Biomedical subjects

T Rodriguez

Publications and source records attributed to T Rodriguez.

34 records · Page 2Linked to original sources
PubMed1994

Studies of human granulocyte phagocytosis stimulation by tuftsin.

Tuftsin (Thr-Lys-Pro-Arg), a natural immunomodulating peptide originally found to stimulate phagocytosis by polymorphonuclear leukocytes (PMNs), is now known to bind to both PMNs and monocyte-macrophages, affecting their phagocytosis and other functions. The potential roles of tuftsin in surgery-related infections have been documented using animal models. However, there have been some difficulties in demonstrating the phagocytosis-stimulating activity of tuftsin. In view of this, we have developed a suitable human PMN phagocytosis assay for tuftsin and performed preliminary kinetic studies. The assay was performed on 24-well plates between PMNs and fluorescent microspheres. The greatest effect of tuftsin over the control was observed under the following conditions: 15 min incubation at 37 degrees C with 5 micrograms/ml tuftsin and a 50:1 ratio of particle to PMN. Particles bound on the surface of PMNs were removed by washing and trypsin treatment, followed by centrifugation through fetal bovine serum. This allowed us to utilize flow cytometry in this study. A flow cytometric procedure was then successfully adapted to human PMN phagocytosis that established a high correlation between microscopic evaluation and flow cytometry of phagocytosis. In addition to the above determinations of the percentage of phagocytic cells, we evaluated the effect of tuftsin on the number of particles engulfed by PMNs. Under the above optimum conditions, tuftsin has greater impact on the number of particles engulfed than on the percentage of phagocytic cells.

Amino Acid Sequence↗
PubMed1994

Availability and utilization of health promotion programs and satisfaction with health plan.

There has been increasing interest in using patient satisfaction as an indicator of quality of care by the purchasers of health plans, as well as the basis for marketing by competing plans. Few studies have examined if availability and utilization of health promotion programs are associated with patient satisfaction with the health plan. Data from the Bay Area Business Group on Health 1992 Employee Medical Plan Satisfaction Survey were used to examine these relationships. The findings indicate that persons enrolled in staff-model health maintenance organizations are much more likely to be offered health promotion programs by their plan or physician compared with persons enrolled in independent practice association-model health maintenance organizations and indemnity plans. However, regardless of plan type, employees who have been offered stop-smoking programs, stress management programs, weight-control programs, cholesterol screening and blood pressure screening, or any health promotion program by their plan or physician are more satisfied with their health plan than whose who have not. In addition, employees who have participated in a health promotion program also are more satisfied than employees who have not participated in such a program. The findings have important implications for designing and restructuring health plans to better meet consumer preferences.

California↗
PubMed1994

Stimulation of phagocytic activity of murine Kupffer cells by tuftsin.

Tuftsin (Thr-Lys-Pro-Arg) is a natural immunomodulating peptide. We have investigated for the presence of a specific tuftsin receptor on murine Kupffer cells using fluorescein-labeled tuftsin, which retains full biological activity. After incubation with fluorescein-labeled tuftsin, Kupffer cells displayed clear binding of this compound on the plasma membrane. Excess tuftsin inhibited this binding, indicating the presence of specific tuftsin receptors on the Kupffer cells. We then investigated the effect of tuftsin on the phagocytic activity of these cells. Phagocytosis assays were performed on 24-well plates between murine Kupffer cells and fluorescent microspheres. The greatest stimulatory effect of tuftsin on percent phagocytic cells over the control value was observed when the cells were incubated with particles at 1 microgram/ml tuftsin for 15 min at 37 degrees C with a particle-to-Kupffer cell ratio of 50:1. Tuftsin also markedly increased the number of particles engulfed by Kupffer cells under the same conditions. These results indicate that Kupffer cells have specific tuftsin receptors; thus tuftsin can stimulate phagocytic activity of Kupffer cells, which constitute the majority of macrophages in the host and are situated strategically in the liver for host defense.

Amino Acid Sequence↗
PubMed1993

Effect of pulse frequency and amplitude of D-Trp6-luteinizing hormone-releasing hormone on the pulsatile secretion of prolactin and LH.

This work analyzes the effect of the pulse amplitude and frequency of a potent LHRH analog, D-Trp6-LHRH, in a perfusion system of isolated rat pituitary cells. To this purpose, we studied the LH and PRL secretion in different conditions: basal secretion, secretion after increasing concentrations of D-Trp6-LHRL (0.001, 0.01, 0.1 and 1 nM) secretion in function of the pulses frequency (2,3, and 4 pulses per h) and amplitude (0.1, 1 and 10 nM). The principal findings were: 1. The basal LH and PRL secretions was pulsatile; 2. The stimulation of LH by the analog was not dose-dependent; 3. When more than 2 pulses per h were administered, a rapid desensitization of gonadotroph to release LH (at 20-30 min) occurred; 4. There was a loss of pulsatility of PRL secretion with an increase in the pulse frequency and amplitude of the D-Trp6-LHRH, which was produced parallelly to the desensitization of the gonadotroph to release LH. In summary, these findings suggest that a rapid loss of pulsatility of the PRL when the D-Trp6-LHRH pulse frequency and amplitude is increased might be due to the early desensitization of the gonadotroph to the analog.

Animals↗
PubMed1993

A cutaneous multilobated B-cell lymphoma.

A patient with multilobated B-cell malignant lymphoma with lesions limited to the skin is described. The light, electron microscopic, and immunohistochemical features of this unusual morphologic variant of non-Hodgkin's lymphoma are described. The nosologic position of this histologic subtype is discussed. The clinical course, with lesions confined to the skin, and the response to treatment suggest a favorable prognosis.

Aged↗
PubMed1993

Managed care for preventive services: a review of policy options.

In summary, the managed care system we propose for preventive services is designed to limit the potential for overcare under FFS payment and for undercare under capitation and comprehensive fixed fees. It bases payment on the provision of a complete set of preventive services, thus limiting the tendency of physicians to provide only the relatively high-profit services, such as screening tests, while neglecting the lower-profit services, such as counseling. It also allows primary care providers to outsource selected services to lower-cost providers, such as laboratories, health educators, and counselors, and community-based health promotion programs, thus encouraging greater efficiency. In addition, the proposed system funds both primary and high-risk preventive case management to ensure that individuals receive preventive services appropriate to their age, sex, and risk factors. Finally, the proposed system monitors the use of preventive services, relying on physician reminders to stimulate the appropriate provision of preventive care and denying payment for unauthorized care. Existing research suggests that none of the individual strategies for managed care can be expected to achieve all of the goals of managing and promoting the appropriate use of preventive services as defined by the U.S. Preventive Services Task Force (1989). To be most effective, we conclude that the strategies need to be coordinated and integrated into the current health care delivery practices of HMOs, PPOs, and point-of-service plans. In addition, the strategies require additional provider training in preventive care. With this support, the proposed model has the potential to improve quality, control costs, and increase the appropriate use of preventive care. While many of the individual components of the proposed managed care model have been evaluated for preventive services, a great deal more research is needed to evaluate the effect of combining these elements into a coordinated and comprehensive approach to managing preventive care. Research is also needed on workable ways to invite people not currently receiving medical care into the health care system to receive preventive care. To inform policy development, the impact of the proposed managed care model--both on preventive services utilization for specific screening, immunization, and counseling services, and on total health care costs and patient health status outcomes--needs to be evaluated.

Cost Sharing↗
PubMed1992

Enzyme-linked immunoelectrotransfer blot test for diagnosis of human hydatid disease.

Sera from 71 patients with surgically confirmed hydatid disease (which is caused by Echinococcus granulosus) were studied by an enzyme-linked immunoelectrotransfer blot (EITB) assay. Sera from patients either with other cestode infections or with another illness were used as controls. Results of the EITB test for hydatidosis were compared with those of the double-diffusion (DD5) test and an enzyme-linked immunosorbent assay (ELISA). In the EITB assay with bovine lyophilized hydatid fluid, three antigen bands of 8, 16, and 21 kDa were diagnostically important. The sensitivity of the assay by using these antigen bands was 80% for hepatic cysts, 56% for pulmonary cysts, and 56% for cysts located in multiple organs. In sera from controls, the specificity of the EITB assay was 100%. Cross-reactions to the 8-, 16-, and 21-kDa bands occurred, respectively, in 12, 4, and 4% of sera from patients with cysticercosis. No cross-reactions were noted in patients infected with Hymenolepis nana. The ELISA in which swine hydatid fluid was used as the antigen was as sensitive as the EITB test but was less specific (80%) and frequently cross-reacted with sera from patients with other cestode infections. The sensitivity of the DD5 test, which uses sheep hydatid fluid, was low (47%) , but its specificity was as high as that of the EITB assay. However, in patients with cysticercosis, cross-reactions were observed in 23% of sera tested. Despite the higher sensitivity found with the EITB assay, 23% (n = 5) of the serum samples that were positive by the DD5 test were not detected by the EITB assay. The EITB assay offers greater sensitivity and specificity than do the ELISA and the DD5 test. The highest proportion of hydatid cases is detected when the EITB and DD5 tests are run simultaneously.

Antigens, Helminth↗
PubMed1991

A comparative study of [Leu1]Tuftsin and tuftsin, a natural phagocytosis-stimulating peptide.

1. [Leu1]tuftsin was reported to have greater phagocytosis-stimulating activity than tuftsin (Thr-Lys-Pro-Arg). 2. However, a study on inactivation of tuftsin by polymorphonuclear leukocytes (PMNs) demonstrated that leucine aminopeptidase, an ecto-enzyme, located on PMN surface was responsible for this mechanism. 3. Since leucine aminopeptidase is known to cleave Leu more easily than Thr at the N-terminal position of peptides, this suggested to us that [Leu1]tuftsin might then be inactivated by PMNs more easily than tuftsin, and thus this analog might be less active than tuftsin. 4. In addition, many tuftsin preparations used in earlier studies were not fully active, as high-performance liquid chromatography was not available to separate out many contaminating diastereomers. 5. In view of this, we have synthesized and purified [Leu1]tuftsin and compared its phagocytosis-stimulating activity with tuftsin. 6. Our results indicate that [Leu1]tuftsin is not as active as tuftsin in stimulating phagocytosis.

Amino Acid Sequence↗
PubMed1990

Tuftsin-enhanced thymidine incorporation by murine splenic monocytes.

Tuftsin (Thr-Lys-Pro-Arg), a natural immunomodulating peptide originally found to stimulate phagocytosis by polymorphonuclear leukocytes (PMN), is now known to bind to both PMN and monocyte-macrophages, affecting many of their functions. Administration of tuftsin induces leukocytosis in vivo. We have recently observed that while tuftsin remains in the cytoplasm upon binding and internalization in human PMNs, it translocates into the human monocyte nucleus, suggesting that tuftsin may directly affect growth of monocytes. We have therefore examined the effect of tuftsin on [3H]thymidine incorporation in fractions of murine splenocytes to identify a cell population responding to tuftsin. Tuftsin showed the greatest effect in [3H]thymidine incorporation of splenocytes over controls at optimum conditions of 2% fetal bovine serum and 1 microgram/ml of tuftsin. Splenocyte fractionation by Lymphocyte Separation Medium indicated that tuftsin primarily affects the mononuclear cell fraction; further fractionation revealed that tuftsin affects mostly the monocytes that adhered to plastic. We subsequently further purified the splenic monocytes by repeated plastic adhesion and Percoll gradient separation, to show that tuftsin increases [3H]thymidine incorporation of these highly purified monocytes.

Amino Acid Sequence↗
PubMed1990

Miller Fisher syndrome associated with Q fever.

A 51 year old woman with pneumonia developed Miller Fisher syndrome. Indirect immunofluorescence tests showed antibodies against Coxiella burnetti. Miller Fisher syndrome associated with Q fever has not been described previously.

Antibodies, Bacterial↗
PubMed1989

CEA in colonic adenocarcinomas and precancerous lesions. An immunohistochemical study with a novel monoclonal antibody.

Using a new anti-CEA (CB-CEA-1) murine monoclonal antibody, the expression of carcinoembryonic antigen (CEA) was studied in normal, premalignant and malignant human adult tissues with particular emphasis on colorectal mucosa. The CB-CEA-1 epitope was poorly expressed in normal adult tissues but was consistently found in colon cancers and adenomas in distinctive immunohistochemical patterns. Some apical staining was found with CB-CEA-1 in cells of normal colon mucosa whereas colon adenocarcinomas had a predominantly cytoplasmic staining pattern. Colonic adenomas presented a varied staining pattern. Some showed apical staining, others a CEA distribution pattern similar to that of adenocarcinomas, particularly those with a villous component. Our findings indicate a differential expression of CB-CEA-1 in adenoma cells in relation to their potential for malignant transformation. The possible usefulness of this Mab defined epitope for diagnostic and therapeutic purposes is indicated.

Adenocarcinoma↗
PubMedDate not supplied

[Long-term infusion of L-asparaginase--an alternative to intramuscular injection?].

Nine children of the ALL-REZ BFM 87 and 90 trial received L-Asparginase (L-ASP) as a continuous infusion for 48-72 hs (i.e. 25 therapy cycles). Seven patients had had an allergic reaction towards an i.m. application (i.m., 29 therapy cycles). Two further patients got L-ASP initially as continuous infusion. The i.m. applications were carried out 19 times with Erwinia and 10 times with E. coli-Asparaginase, the continuous infusions 15 times with Erwinia and 10 times with E. coli-Asparaginase. In case of four patients continuous infusions of the same L-ASP type (E. coli or Erwinia) was well tolerated, after there had been an allergic reaction after i.m. application. Allergic reactions after i.m. application occurred during 10 courses as local painful erythema, during five courses as urticaria, during four courses as a general exanthema during one course as difficult breathing and during a further course as drop in blood pressure. After continuous infusion of L-ASP urticaria and difficult breathing occurred once and a transient exanthema two times. There was no anaphylactic reaction in any case. These data show that i.m. application of L-ASP causes no life-threatening side effects but allergic reactions (local pain and swelling) which clearly impaired general condition. Continuous infusion is a pharmacologically equivalent alternative with less impairment of the patients' general condition.

Adolescent↗
PubMedDate not supplied

Young children's understanding of perception, desire, and emotion.

Very young children seem to know that people experience several mental states: desires, perceptions, emotions. In three studies, we investigated 2- and young 3-year-olds' judgments and communications about how these states connect together in people's lives and minds. Two experimental studies with 56 participants demonstrated young children's understanding of at least one set of connections: In appropriate circumstances, a person's perception of desirable or undesirable objects leads to related emotional experiences. A complementary investigation of four young children's everyday conversations demonstrated their awareness of and expression of several additional connections between people's desires, perceptions, and emotions.

Child Development↗
PubMedDate not supplied

Stability of sterile saline solutions of synthetic tuftsin, a naturally occurring immunomodulating peptide.

Tuftsin, Thr-Lys-Pro-Arg, is a natural immunomodulating peptide originally found as a phagocytosis-stimulating factor for polymorphonuclear leukocytes. The peptide is now known to elicit various other activities including antimicrobial, antiviral and antitumor effects in vivo. Preliminary human studies revealed antitumor and anti-AIDS activities. In view of this clinical potential, we performed studies on the stability of sterile saline solutions of tuftsin stored at 25 degrees C, 5 degrees C, -20 degrees C or -70 degrees C utilizing a phagocytosis assay and analytical HPLC. Tuftsin stored at -20 degrees C or -70 degrees C gradually lost its phagocytosis-stimulating activity; tuftsin stored at 25 degrees C or 5 degrees C lost its phagocytosis activity rather rapidly. By 6 months, tuftsin stored at 25 degrees C lost all activity, and by 12 months, it significantly inhibited phagocytosis. In contrast, HPLC analysis indicated very minor changes. While tuftsin stored at 25 degrees C lost almost all activity by 6 months, we detected appearance of only 1% impurities by HPLC. This study indicates that if its activity is to be preserved, solutions of tuftsin must be frozen for storage.

Adjuvants, Immunologic↗