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Biomedical subjects

L A Fernandez

Publications and source records attributed to L A Fernandez.

At least 55 records · Page 3Linked to original sources
PubMed1988

The emergence and establishment of a clonal subline with partial duplication of chromosome 1q from a tumorigenic human chronic lymphocytic leukemic B-cell line.

Sequential analysis was performed on a tumorigenic human B-cell chronic lymphocytic leukemia cell line in which the initial population consisted of two abnormal clones, one with trisomy 12 (47%), the other with duplication of 1q; that is, 46,XY,dup(1)(q11----q32) (10%), and rest of the population had a normal karyotype. The clone with 1q+ marker expanded steadily and after 11 weeks became the only proliferating cell population in vitro and remained so till the end of an observation period of 75 weeks. All tumors recovered from nude mice that were inoculated with this newly established subline had retained the 1q+ marker. All the secondary clones also carried this aberration.

Animals↗
PubMed1988

Progression of a human B cell chronic lymphocytic leukemia line in nude mice.

Subcutaneous (s.c.) inoculation of the 85-4LN subline, derived from a lymph nodal metastasis of the Epstein-Barr virus (EBV) transformed human chronic lymphocytic leukemia (CLL) B cell line, EBV-CLL (1), produced progressively growing lethal tumors in 31/35 nonirradiated (88.6%) and 22/25 (88%) of whole-body irradiated (440 rad) nude mice. In contrast, EBV-CLL(1) could produce progressive tumors only in irradiated nude mice. All 85-4LN cells had Epstein-Barr virus nuclear antigen and reacted with pan B and anti-la antibodies. The morphology and ultrastructural features was consistent with the lymphoblastoid nature of the cells. In all s.c. tumor bearing mice, there was enlargement of the spleen and draining lymph nodes. Karyological studies revealed human cells in the spleen and draining nodes in all the mice investigated. Metastases in nonlymphoid organs were seen in 1/8 irradiated and 8/12 nonirradiated mice. The subline contained 77% cells with 47,XY, +12 and 23% cells with 45,XY karyotype. The clone with trisomy 12 did not have any growth advantage either in s.c. transplants or in splenic/lymph nodal metastases. Treatment with the maximum permissible doses of methotrexate (MTX) or chlorambucil (CBL) revealed xenografts to be more sensitive to MTX than CBL. A clone with a 1g+ marker, i.e., 46,XY,Dup(1) (q11----q32) appeared to be associated with resistance to CBL. We have not seen any previous report on the growth and dissemination of human CLL B cells in nonirradiated nude mice. The 85-4LN subline, thus, provides a model for studying the progression, dissemination and therapeutic response of human CLL-B cells.

Animals↗
PubMed1988

Busulfan-induced sideroblastic anemia.

Patients in the stable phase of chronic myelogenous leukemia (CML) are usually treated with busulfan. The bone marrow of patients with CML may be exquisitely sensitive to busulfan, and occasionally such patients develop pancytopenia, secondary to hypoplasia or aplasia of the bone marrow, which is presumed to be due to busulfan-induced marrow toxicity. We report a case of Philadelphia chromosome-positive CML who developed pancytopenia while being treated with busulfan; however, the patient's bone marrow was not hypoplastic or aplastic but rather hyperplastic with sideroblastic changes. Busulfan is not known to cause sideroblastic changes, so this was considered to herald a transformation into acute leukemia. Busulfan was stopped, and only supportive treatment was given. To our surprise approximately 22 weeks after busulfan was stopped, the sideroblastic changes had disappeared and the bone marrow again showed features of CML. This case suggests that busulfan may cause sideroblastic anemia.

Anemia, Sideroblastic↗
PubMed1988

Detection of neovascular signals in a 3 day Walker 256 rat carcinoma by CW Doppler ultrasound.

An animal model was used to study tumor blood flow by the Doppler CW technique. The objective was to determine when neovascularity could be detected as a function of tumor size and time since transplantation. A Walker 256 carcinosarcoma tumor was inoculated into the flank of 17 Sprague-Dawley rats. Doppler examinations, using a 9 MHz CW probe, were performed daily from day 0 to day 7. The contralateral flank was used as a control. No signals were detected from the control side nor from the inoculated side until day 3. By day 3, Doppler signals could be easily detected in all tumor implants with a minimum weight of only 50 mg. These signals showed a mean systolic frequency shift of 3.3 +/- 0.47 kHz at 3 days and 3.46 +/- 0.58 kHz at 7 days. The diastolic Doppler shifted frequency was 1.78 +/- 0.31 kHz at 3 days and 1.88 +/- 0.23 kHz at 7 days giving a Pourcelot index of 0.47 +/- 0.1 at 3 days and 0.46 +/- 0.09 at day 7. These figures indicate the presence of low impedance vessels with high velocity flow such as has been reported in many human tumors. The vascular morphology was further evaluated by digital angiography which demonstrated coincidence between the site of the high velocity Doppler signals and the presence of arteriovenous anastomoses manifested by simultaneous arterial and venous filling. Further infusion techniques using India ink or Microfil showed the chaotic arrangement of tumor vessels located around the growing edge of the tumor implant. The development of such vascularity is a well-recognized prerequisite for tumor growth and invasion.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1988

Differences in mortality rate between abrupt and progressive carotid ligation in the gerbil: role of endogenous angiotensin II.

Studies have shown that in comparison to rapid occlusion of a vessel, gradual occlusion produces less severe tissue ischemia due to a more effective development of collateral circulation. As other studies have shown that collateral circulation can be enhanced by stimulation of the endogenous renin-angiotensin II system, it was hypothesized that this system is involved in the mechanism of protection against ischemia that obtains during gradual vascular occlusion. To test this hypothesis, mortality rates were evaluated in gerbils subjected to gradual vascular occlusion by means of progressive carotid ligation while simultaneously infused with inhibitors of the renin-angiotensin II cascade--enalaprilat or saralasin. Groups of animals with either abrupt or progressive carotid ligation infused with saline served as controls. Results showed that (1) in saline-infused animals, there was a significant decrease in the mortality rate of progressive-ligated animals when compared to abrupt-ligated animals, and (2) administration of either enalaprilat or saralasin to progressive-ligated animals resulted in mortality rates that were indistinguishable from those of saline-infused abrupt-ligated animals. These results suggest that the endogenous renin-angiotensin system is indeed involved in an adaptive mechanism that occurs during progressive ligation of the carotid artery, and more specifically, that the relatively benign effect of progressive carotid ligation may be due to the action of angiotensin II to stimulate the development of collateral circulation and reduce the severity of focal brain ischemia.

Angiotensin II↗
PubMed1988

Renin in glioblastoma multiforme and its role in neovascularization.

Significant proliferation of capillaries with hyperplastic vascular endothelium is one of the characteristic histologic features of glioblastoma multiforme (GBM). It has been shown that the renin-angiotensin II cascade stimulates new vessel formation. The presence of renin in several types of highly vascularized neoplasm suggests that it may also be implicated in the mechanism of tumor angiogenesis. In order to study the possible relationship of renin to GBM, immunohistochemical search for human renin was carried out in ten instances of such a tumor. Eight of these cases demonstrated renin-containing neoplastic astrocytes, whereas seven cases of reactive gliosis and six cases of low-grade astrocytoma revealed no renin-containing cells. The immunostaining was not present after preabsorption of the renin antiserum with pure human renin or substitution of preimmune serum for the specific renin antiserum. Because it has also been demonstrated that a product of renin, angiotensin II, has angiogenic properties, it seems reasonable to postulate that renin, through angiotensin II, may play a role in the mechanism of GBM-associated neovascularization.

Brain↗
PubMed1988

The angiogenic properties of the rat vibrissa hair follicle associate with the bulb.

As the hair follicle is one of the most rapidly growing tissues in the body, it must be nourished by a rich blood supply. Histological studies have indicated that the number of vessels about a growing follicle exceeds that about a resting follicle, so we postulated that the hair follicle might provide its own angiogenic stimulus during certain phases of its growth. Reported here are experiments testing the angiogenic properties of the growing (anagen) hair follicle. Using the rabbit corneal pocket angiogenesis assay and cycled anagen rat vibrissae hair follicles, we found that the mesenchymal dermal papilla had no angiogenic properties, but the anagen bulb was angiogenic. These findings suggest a mechanism for the cycling of hair follicles and an example of normal epithelium to mesenchyme interactions.

Animals↗
PubMed1987

Presence of mitomycin resistant T cells in peripheral blood of normal individuals.

T cell colonies can be easily grown from peripheral blood, and are an index of cellular immunocompetence. Mitomycin-treated T cells are used as stimulator cells in mixed lymphocyte reactions and as feeder cells for growth of B cell colonies, the assumption being that mitomycin prevents proliferation of T cells. We tested this assumption by comparing the proliferation of mitomycin-treated T cells in response to stimulation with phytohemagglutinin (PHA) with that of untreated T cells in liquid cultures and in T cell colony assay. We found that incorporation of tritiated thymidine by cells from 11 healthy individuals pretreated with 25, 50 and 100 micrograms/ml mitomycin C was reduced to 13, 11 and 8%, respectively, of that of untreated cells when stimulated by an optimal concentration of PHA (10 micrograms/ml) in liquid cultures. However, parallel experiments with aliquots of the same cells showed that pretreatment with 25, 50 or 100 micrograms/ml mitomycin C merely reduced T cell colonies to 49, 45 and 45%, respectively, of untreated cells. In five additional experiments mitomycin 200 and 400 micrograms/ml reduced T cell colony numbers to 47 and 60%, respectively. Treatment of T cells with 9000 rad completely abolished T cell colony formation. Lower doses of radiation up to 6000 R did not abolish T cell colony formation, although it effectively blocked T cell proliferation to PHA in liquid cultures. 24 h preincubation of T cells with suboptimal doses of PHA and then treatment with mitomycin or radiation did not abolish T cell colony formation. T cells were recovered from the mitomycin-resistant T cell colonies and stimulated in liquid cultures with PHA, untreated or after exposure to 25 micrograms/ml mitomycin C. Incorporation of tritiated thymidine by the mitomycin-treated cells was reduced to 8% of the untreated controls. Our observations suggests: There may be inaccuracies in B cell colony assays using mitomycin-treated T cells because of significant T cell colony formation. There is a population of T cells in the peripheral blood of normal individuals which form colonies and are resistant to mitomycin.

B-Lymphocytes↗
PubMed1986

Production of interferon by peripheral blood mononuclear cells from normal individuals and patients with chronic lymphocytic leukemia.

Peripheral blood mononuclear cells (PBMC) from normal individuals were studied to identify which cells produce alpha-interferon (IFN-alpha) in response to a virus stimulus. It was found that cells both adherent and nonadherent to plastic formed IFN-alpha after induction by any one of several viruses studied. When nonadherent cells were separated on discontinuous Percoll gradients, only the cells in the less dense Percoll fractions produced IFN, whatever the virus used. By indirect immunofluorescence with monoclonal antibodies to HLA-DR and to Leu 11b, the distribution of the HLA-DR+ cells was shown to resemble most closely that of the IFN-producing population. Elimination of these cells (by complement-mediated lysis with the same antibodies) abrogated the IFN response, but NK cells remained and thus do not produce IFN-alpha. In confirmation, elimination of the Leu 11b+ cells had no effect on the amount of IFN produced. PBMC preparations from patients with chronic lymphocytic leukemia (CLL) appeared incapable of producing IFN-alpha but were shown to contain identifiable IFN-producing cells. The low or absent IFN levels in CLL are probably due to the relative scarcity of IFN-producing cells in their PBMC.

Antigens, Surface↗
PubMed1986

Angiotensin II-like immunoreactivity in human ovarian follicular fluid.

Human ovarian follicular fluid (hFF) has angiogenic activity, although the causative factors are unknown. We recently found that hFF contains renin activity which converts renin substrate to angiotensin I (AI). Since the enzymatic cleavage product of AI, angiotensin II (AII), is a potent stimulator of new vessel formation, we have examined Sephadex G-25 column fractions of hFF and extracted hFF and plasma from individual patients for AII-like immunoreactivity (AII-IR). Eluent fractions from Sephadex G-25 column chromatography of hFF had significant AII-IR which eluted in the same fractions as synthetic AII. Individual, extracted FF samples contained approximately 10 times higher levels of AII-IR than extracts of plasma from the same patients. Serial dilutions of the Sephadex column fractions and extracted FF and plasma inhibited binding of 125I-AII to rabbit anti-AII serum in a manner parallel to the inhibition caused by synthetic AII, indicating that the detected immunoreactivity was not due to non-specific assay interference. In summary, the results indicate the presence of significant AII-like immunoreactivity in hFF. AII may now be considered as a potential mediator of the angiogenic activity present in hFF and may play an important paracrine and/or autocrine role in physiologic events in the ovary.

Angiotensin II↗
PubMed1986

Renin in angiolymphoid hyperplasia with eosinophilia. Its possible effect on vascular proliferation.

A hypertensive man became normotensive after the surgical removal of two subcutaneous masses of angiolymphoid hyperplasia with eosinophilia. To demonstrate that angiolymphoid hyperplasia with eosinophilia is a renin-producing pathologic condition, Bowie stain for juxtaglomerular cell granules and immunohistochemistry for human renin were used. Bowie stain was positive in cells showing cytoplasmic granules similar to those found in the juxtaglomerular cells of the kidney. Immunohistochemical staining using antiserum against human renin showed the presence of renin-containing cells. This staining was not seen after substitution of the specific renin antiserum by preimmune serum, by the renin antiserum preabsorbed with pure human renin, or with plasma from a patient with high-plasma renin activity. Renin-containing cells were located in areas surrounding vascular structures and were apparently neither endothelial, mast, nor lymphoid cells. Six of eight additional cases of angiolymphoid hyperplasia with eosinophilia were positive for renin-containing cells. Renin has been described in several other histologically highly vascularized tumors. Since a product of renin, angiotensin II, has been found to have angiogenic properties, it is possible to postulate that renin, through angiotensin II, may stimulate the proliferation of vessels and, therefore, may be involved in the pathogenesis of angiolymphoid hyperplasia with eosinophilia.

Abdominal Muscles↗
PubMed1986

Immunoregulation of B lymphocyte colony formation by T cell subsets in patients with chronic lymphocytic leukemia.

Normal B lymphocytes are activated, proliferate, and then differentiate into plasma cells and secrete immunoglobulin (Ig). We have reported that chronic lymphocytic leukemia (CLL) T4 cells help and CLL T8 cells lack suppressor effects on Ig synthesis by normal B cells (Blood 62:767, 1983). We have now explored the earlier phase, proliferation, using B cell colony formation; in semisolid media. B lymphocyte colonies from normal individuals and from patients with CLL were grown in 0.3% agarose overlayed with T cells or T cell subsets and the B cell mitogen staphylococcal protein A. Enriched T cells, OKT4 or OKT8, were obtained either by sheep erythrocyte rosettes or depletion of OKT8 or OKT4 cells by monoclonal antibody or complement, respectively. Twenty thousand B cells from normal subjects yielded 65 +/- 9, 64 +/- 7, and 19 +/- 6 colonies with autologous unfractionated T-, OKT4-, or OKT8-positive cells, respectively. This compared to 29 +/- 11, 81 +/- 11, and 15 +/- 4 colonies from patients with CLL with added autologous unfractionated T-, OKT4-, or OKT8-positive cells. To determine whether the fewer number of colonies in both normal subjects and patients with CLL with OKT8-positive cells was due to suppression or lack of help, the number of OKT4-positive cells was held constant, and OKT8-positive cells were added in increasing numbers. No suppression of colony formation could be demonstrated. Furthermore, the addition of increasing numbers of concanavalin A (Con A)-activated OKT8-positive cells did not suppress colony formation. These results suggest that the CLL T cell subsets behave in a functionally similar manner to normal T cell subsets, namely, (1) that normal and CLL B cell colony growth is helped by OKT4 cells; and (2) in contrast to immunoglobulin secretion by B cells, neither normal nor CLL OKT8 cells, unstimulated or activated by Con A, suppress B cell colony growth.

Aged↗
PubMed1986

Growth and spread in nude mice of Epstein-Barr virus transformed B-cells from a chronic lymphocytic leukemia patient.

Subcutaneous inoculation of Epstein-Barr virus (EBV) transformed peripheral blood B-lymphocytes (PBL) from an untreated chronic lymphocytic leukemia (CLL) patient produced progressively growing lethal tumors in 4 of 11 whole body irradiated (440 rads) nude mice. In one tumor bearing mouse there was splenomegaly and generalized enlargement of lymph nodes. Chromosomal analysis and membrane immunofluorescence revealed that cells in all the 4 s.c. tumors and a proportion of cells in the enlarged spleen and lymph nodes had human chromosomes and contained human kappa or lambda chains demonstrating that these were polyclonal human B-cells. Epstein-Barr virus associated nuclear antigen could be detected in 100% of cells in all the 4 EBV transformed B-cell lines in vitro and aliquots of cells from several s.c. tumors and metastatic lesions examined. Successful serial transplantation into irradiated nude mice was possible for at least 3 generations with one of the 4 s.c. tumors. During serial transplantation, spread of tumor cells to the spleen and lymph nodes could be detected in all the 3 passage mice investigated; however, there was no evidence in any mouse of dissemination of tumor cells into the bloodstream or into any organ other than lymph nodes and spleen. s.c. tumors also developed in a proportion of irradiated nude mice after inoculation of cells from two other s.c. tumors and the metastatic spleen and lymph nodes, but all these tumors regressed during the first or second transplant passage. Two % of PBL from the untreated patient and 4% of EBV transformed PBL maintained in vitro were found to have trisomy of chromosome 12 which is the most frequently reported anomaly associated with human CLL B-cells. It is highly probable that the cells with trisomy were derived from the leukemic clone of this patient. Cells with this trisomy predominated in most metastatic sites compared to the parent s.c. tumors. Inoculation of irradiated nude mice with EBV transformed PBL from this patient after chlorambucil therapy (100% metaphase plates with 46,XY,11q+ karyotype) or with EBV transformed PBL from 2 normal adults failed to produce any progressively growing tumor in a total of 12 irradiated animals observed greater than 300 days. Although there are several reports of EBV induced immortalization of CLL B-cells in vitro, we have not seen any previous report on the successful serial transplantation and dissemination of EBV transformed CLL B-cells in nude mice.

Animals↗
PubMed1986

Aggressive natural killer cell leukemia in an adult with establishment of an NK cell line.

There have been many reports of cases in which chronic increases in the numbers of natural killer (NK) cells have been reported. Whether this is reactive or neoplastic in nature has been debated. We report the first case of an aggressive NK cell leukemia in an adult with establishment of an NK cell line. A 70-year-old man had two spontaneous episodes of jejunal perforation and one month later developed a severe febrile illness with moderate splenomegaly. Hemoglobin was 13.1 g/L, and WBC count was 1.8 X 10(9)/L with 2% large granular lymphocytes (LGLs). Platelet count was 143 X 10(9)/L; prothrombin time (PT) and partial thromboplastin time (PTT) were normal. Bone marrow was infiltrated with 25% to 30% LGLs; serum lysozyme was normal. Serum LDH was initially 1,191 U/L and rose to 6,408 (normal 240 to 525 U/L). Ten days later, the WBC count increased to 99.9 X 10(9)/L with 70% LGL cells; the PT and PTT increased, and the platelet count dropped. No bacterial or viral cause of fever was identified. The cells from peripheral blood were LGLs that stained positively for acid phosphatase. All of the LGLs reacted with a monoclonal antibody reactive with NK cells (LEU-11b). Functionally, the patient's peripheral blood mononuclear cells (PBMs) demonstrated 100 times more lytic activity against K562 tumor cell lines than did normal PBMs. The patient's PBMs were propagated in vitro. The cultured cells showed the morphological, cytochemical, immunological, and functional characteristics of NK cells. In addition, partial trisomy involving chromosome 1 q with duplication in regions of q21 through q31 was observed in all metaphases analyzed. The extra chromosome 1q with duplication in regions q21 through q31 was translocated to the p-terminal of chromosome 5. One percent to 5% of normal PBMs comprise NK cells; in most cases, leukemias arise from normal phenotypic counterparts. This case demonstrated that aggressive NK cell leukemia may occur in adults. In addition, the chromosomal abnormalities suggest that this is not a reactive process but a malignancy.

Aged↗
PubMed1985

Renin-like activity in ovarian follicular fluid.

Angiogenesis is a feature of ovarian follicle and corpus luteum development. Ovarian homogenates and follicular fluid (FF) contain factors that stimulate new vessel formation. Because the renin-angiotensin system has been shown to facilitate angiogenesis, renin activity was measured in FF and plasma from 20 normal, ovulatory women who were undergoing in vitro fertilization and were therefore stimulated with human menopausal gonadotropin/human chorionic gonadotropin. Serum estradiol (E2) and FF E2 and progesterone (P) were also determined and correlated with FF and plasma renin activity. FF renin activity was significantly higher than plasma renin activity (55.8 +/- 7.9 versus 3.8 +/- 0.7 ng of angiotensin I/ml/hour, P less than 0.001). Positive correlations were found between FF E2 and renin activity (r = 0.53, P less than 0.05). There was also a correlation between plasma renin activity and serum E2 (r = 0.69, P less than 0.05). No correlation was present between FF P and renin activity. The high renin-like activity present in FF after stimulation with gonadotropins could be involved in the mechanism of angiogenesis and may play an important role in events related to reproductive processes.

Estradiol↗
PubMed1985

Neovascularization produced by angiotensin II.

Following vascular occlusion, development of collateral circulation occurs in at least two time-related phases: (1) the fast enhancement of the function of preexisting channels and (2) the slow formation of new vessels. Inasmuch as the renin-angiotensin system can act as a protective mechanism against local ischemia by activating preexisting collateral vessels, it is of interest to establish whether angiotensin II also produces stimulation of new vessel formation. Angiotensin II or cholecystokinin, an unrelated peptide, was incorporated in a slow-release formulation polyacrylamide gel and implanted in a pocket made in the rabbit cornea. Periodic examinations revealed that angiotensin II significantly stimulates new vessel formation; maximum values were attained in approximately 2 to 3 weeks. In contrast, cholecystokinin or polyacrylamide gel alone failed to stimulate any significant new vessel formation. Positive neovascularization was present in 85% of the total number of corneas implanted with angiotensin II, whereas 14% and 8% positive results were seen in the corneas implanted with either cholecystokinin or polyacrylamide gel alone, respectively. It is concluded that angiotensin II not only facilitates the activation of preexisting collateral vascular pathways but also has angiogenic properties and therefore could play an active role not only in the fast but also in the slow phase of the development of collateral circulation.

Acrylic Resins↗