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Biomedical subjects

H Burgos

Publications and source records attributed to H Burgos.

At least 19 recordsLinked to original sources
PubMed2005

Endoscopic gastroenteric anastomosis using magnets.

BACKGROUND: Current management of malignant obstruction of the upper digestive tract includes surgical gastrointestinal bypass or endoscopic insertion of self-expandable metal stents. The safety, efficacy, and long-term patency rates of anastomoses created using the novel technique of endoscopic gastroenteric anastomosis using magnets (EGAM) are evaluated in this study. PATIENTS AND METHODS: 15 patients (13 men, 2 women; mean age 64.5 years) with malignant obstruction, who underwent EGAM and had monthly follow-up between December 2001 and May 2003, were included in this study. RESULTS: The procedure was successful in 13 patients (88.66 %). The mean survival was 5.23 months. There were four minor complications (30.76 %) during the follow-up period. CONCLUSION: Our results demonstrate the feasibility, safety. and efficacy of this technique for creating a gastroenteric anastomosis. The success rate was 86.6 %, there were no immediate complications, and there was no mortality related to the procedure.

Aged↗
PubMed2001

Lesion of the bulbospinal noradrenergic pathways blocks desipramine-induced inhibition of the C-fiber evoked nociceptive reflex in rats.

Desipramine-induced inhibition of spinal cord nociceptive transmission was studied in rats with or without lesion of the bulbospinal noradrenergic system by recording the C-fiber evoked nociceptive reflex from a hind limb. Bulbospinal noradrenergic projections were lesioned by injecting intrathecally 20 microg of 6-hydroxydopamine 2 weeks before the electrophysiological experiments. Results show that desipramine (5, 10 and 20 mg/kg intraperitoneally) produced dose-dependent inhibition of the C reflex response duration in rats having intact noradrenergic bulbospinal systems. The inhibitory effect of desipramine was reduced or even abolished in rats pre-treated with 6-hydroxydopamine. In addition, [3H]-noradrenaline uptake was significantly lower in spinal cord slices arising from 6-hydroxydopamine lesioned animals, as compared to that from intact rats. These observations support the notion that the antinociceptive activity of antidepressants with noradrenergic selectivity depends on a normal rate of endogenous noradrenaline released by bulbospinal neurons.

Adrenergic Agents↗
PubMed1989

The healing of chronic venous leg ulcers with prepared human amnion.

Forty chronic venous leg ulcers were treated, before split skin grafting, with human amnion prepared in one of the four following ways: tissue-culture-maintained, frozen, fresh or lyophilised. Although there was no significant statistical difference in the results obtained with the different preparations of amnion, we found that lyophilised amnion was at least as good as the other preparations in promoting a good take of the skin grafts and was the simplest to store and use. It also produced the shortest healing times. Frozen and fresh amnion were easier to prepare than lyophilised amnion but gave a lower graft take and a longer healing time. Tissue-culture-maintained amnion was the most difficult to prepare and gave the poorest results. Its use was abandoned during the trial because of technical difficulties and a high infection rate.

Aged↗
PubMed1989

Effect of decidua angiogenic factors on experimental dermis allografts.

Meshed human dermis allografts containing human uterine angiogenic factor were implanted over full thickness surgical skin wounds in rats. Enhanced angiogenesis of the wound bed, three times more than that observed in control grafts, was found in experimental grafts at 3 days postimplantation. This was accompanied by a greater amount of granulation tissue formation, enhanced granulation tissue penetration into the dermal grafts and accelerated incorporation of the grafts. Angiogenesis of the wound bed regressed to control levels at 7 days postimplantation. The growth and penetration of the granulation tissue and the accelerated incorporation of the dermis grafts, however, continued ahead in the experimental grafts while necrosis appeared in the control grafts. The relevance of these results for acceleration of wound healing and improvement of the wound bed for subsequent application of cultured epidermal grafts is discussed. This method may be extended to the treatment of ulcers and burns.

Angiogenesis Inducing Agents↗
PubMed1989

Placental angiogenic and growth factors in the treatment of chronic varicose ulcers: preliminary communication.

A short-term clinical study on the effect of purified angiogenic and growth factors from human term placenta in the treatment of chronic varicose ulcers was carried out in 18 patients. Patients were randomly allocated to receive a maximum of two dressings containing or not containing these factors. The amount of granulation and epithelial tissue was clinically estimated 48 hours after each application. Patients treated with placental angiogenic and growth factors showed increased granulation and epithelial tissue. These results indicate that placental factors may be used for acceleration of wound healing.

Adult↗
PubMed1986

Angiogenic factor from human term placenta. Purification and partial characterization.

Angiogenic and growth promoting factors from human amniochorion and placenta at term were released mostly as high molecular weight components (factor-carrier protein higher than 100,000 molecular weight) by extraction with 10% propan-2-ol, distilled water, and 50 mmol l-1 Tris/HCl pH 7.2 containing 50-150 mmol l-1 NaCl. They were isolated from the extracting media by adsorption on DEAE-Sepharose CL6B, a chromatographic agar based anion exchanger, and fractionated by chromatographic permeation on dextran gel Sephacryl S-300 yielding a low molecular weight component (between 400 and 1100 mol wt) with angiogenic and mitogenic capacities. Chromatographic behaviour and physio-chemical characteristics suggest it may be a peptide. Presence of an angiogenic and mitogenic factor in human amniochorion may explain the profuse neovascular formation and increased rate of healing obtained in the treatment of chronic ulcers by application of amniochorionic membranes as biological dressings. Preparation of purified angiogenic factor, on the other hand, opens the possibility of its wider application in the treatment of burns, open wounds and denuded areas in general.

Amnion↗
PubMed1983

Angiogenic and growth factors in human amnio-chorion and placenta.

Human amnio-chorionic membranes and placenta maintained in culture release factors with angiogenic and mitogenic capacities at concentrations corresponding to nanogram amounts of protein. Angiogenic activity of amnio-chorion and placenta-conditioned media was assessed by their ability to stimulate neovascularisation in the dorsal subcutaneous fascia in the rat and the chorio-allantoic membrane in the chick embryo. Mitogenic characteristics were assessed by their ability to initiate DNA synthesis in cells at resting state, unstimulated peripheral blood lymphocytes and serum-deprived 3T3 fibroblasts. These growth promoting factors can be isolated from amnio-chorion and placenta-conditioned media mostly as factor-protein complexes of high molecular weight (higher than 100000 daltons) by gel filtration, and dissociated by magnesium chloride in components of low molecular weight including molecules readily diffusable through dialysis membranes of 2000 molecular weight cutoff. Presence of angiogenic and mitogenic factors in amnio-chorion suggests they might play a role in wound healing when amniotic membranes are used as biological dressings, besides the role they may play, in conjunction with placental factors, in embryonic and foetal development.

Amnion↗
PubMed1982

Plasminogen binding by human amniochorion. A possible factor in premature rupture of membranes.

Forty-six human fresh amniochorion membranes obtained at cesarean section were found to contain from 0 to 5% dead cells in the amniotic epithelial layer by direct counting and spectrophotometric analysis of trypan blue extracts. With the use of a double marker system it was discovered that many of the dead cells failed to bind the DNA-chelating fluorochrome propidium iodide but reacted with fluorescein isothiocyanate-labeled antibodies to human plasminogen. In addition, both fresh and cultured human amniotic epithelial cells that had plasma membranes damaged by either cryogenic shock or cytocentrifugation specifically bound plasminogen from serum, plasma, or amniotic fluid to cytoplasmic structures. Binding did not occur in other control proteins, but plasminogen was bound from very dilute solutions, suggesting specific and tight binding inside the cell. We propose that such plasminogen can be activated to plasmin within the cell by either plasminogen activators or lysosomal proteases and that this sets into motion a progression of events that are potentially damaging for the amniochorion, perhaps being of relevance in the pathophysiology of premature rupture of the membranes in human pregnancy.

Amnion↗
PubMed1981

The maintenance of human amniotic membranes in culture.

A culture systems is described for the long-term maintenance of human amnion in vitro. This has been developed because of the need for an amnion organ culture to study immunological aspects of this extra-embryonic membrane as well as the increasing surgical use of amnion in wound healing. The intact amnion can be maintained for 2-3 weeks with 50-90% viability as determined by morphological and trypan-blue extraction techniques. This puts forward the feasability of developing an amnion bank for clinical investigations of wound healing as well as the possibility of in vitro studies of this membrane in the materno-fetal relationship in human pregnancy.

Amnion↗
PubMed1980

Human amnion as an adjunct in wound healing.

Biopsy specimens from the beds of leg ulcers of fifteen patients were obtained before and after the application for 5 days of cultured human amnion. After amnion application there was considerable granulation tissue in the ulcer bed and microscopical evidence of thinned connective tissues, vessel development, more compact resolution of vascular basement membranes, and many more factor VIII granules within endothelial cells. These findings suggest the presence of angiogenic factors in human amnion and this could explain the hitherto unexplained success of amniotic membranes in surgical practice.

Amnion↗
PubMed1979

Failure of long surviving, passively enhanced kidney allografts to provoke T-dependent alloimmunity. I. Retransplantation of (AS X AUG)F1 kidneys into secondary AS recipients.

Long survival of (AS X AUG)F1 rat kidney allografts in AS recipients was induced by passive enhancement with AS anti-AUG antiserum at the time of grafting. After 1-3 mo, the kidney allografts were transferred to second AS recipients, either naive or sensitized against AUG tissue. Naive second recipients did not reject the grafts acutely and failed to mount T-dependent immunity against AUG targets. When later challenged with spleen cells carrying the AUG haplotype, the naive second AS recipients showed strong IgM, IgG, and cytotoxic T-cell responses after grafting, and the kidneys were rapidly destroyed by immune rejection in all but one rat. It is concluded that long-surviving kidney allografts fail to activate helper T cells and induce in naive second recipients the same state of unresponsiveness observed in the first recipient.

Animals↗
PubMed1979

Failure of long surviving, passively enhanced kidney allografts to provoke T-dependent alloimmunity. II. Retransplantation of (AS X AUG)F1 kidneys from AS primary recipients into (AS X WF)F1 secondary hosts.

Long surviving, passively enhanced (AS X AUG)F1 kidneys carried by AS recipients were retransplanted into (AS X WF)F1 second hosts. Acute graft rejection did not occur. Only one of six secondary recipients mounted a significant T-dependent IgG lymphocytotoxic antibody response. In all six, generation of cytotoxic T cells was markedly slower and depressed. These results are compatible with the hypothesis that kidney parenchyma, although carrying major histocompatibility complex specificity is able to induce T-independent but not T-dependent alloimmunity. A corollary is that passenger cells are responsible for exciting the T-dependent allimmune response normally observed after grafing. The practical difficulty of eliminating all T-dependent immunogenicity from (AS X AUG)F1 kidneys was emphasized by the observation that a 3-d residence in an intermediate AS recipient was insufficient time to prevent acute graft rejection after retransplantation.

Animals↗
PubMed1977

The immune response to allogeneic rat platelets; Ag-B antigens in matrix form lacking Ia.

Allogeneic rat platelets fail to induce either primary antibody or cell-mediated immune responses despite repeated injections. Platelets bear Ag-B epitopes which are capable of being recognized by antigen-reactive T and B cells since primed rats develop secondary responses after challenge with allogeneic platelets. The secondary responses induced decrease rather than increase on repeated injection of platelets. Repeated injection of allogeneic platelets into nonprimed rats leads to a state of specific, partial non-reactivity; recipients given such treatment show marked depression of cytotoxic antibody responses, but normal cellular immunity after challenge with viable lymphoid cells taken from the platelet-donor strain. Injection of normal rats with allogeneic platelets mixed with 3rd party, viable lymphoid cells, does not provoke an anti-platelet Ag-B antibody response.

Animals↗