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Biomedical subjects

J Cuevas

Publications and source records attributed to J Cuevas.

At least 73 records · Page 4Linked to original sources
PubMed1979

[Pheochromocytoma and sudden death (author's transl)].

Five cases of pheochromocytoma are described in which sudden death was the form of the initial clinical presentation in almost all of them. After a brief review on the history and the incidence of the tumor within the general population, diverse cases are analyzed from a clinical point of view and in relation to the data appeared in the literature. In the analysis of the symptoms emphasis is placed on the important psychomotor manifestations which are present in the majority of those patients and which causes serious difficulties in the initial diagnosis. All of the patients showed signs of shock at the time of being observed or during the course of this observation, and in the majority of them the presence of acute pulmonary edema was confirmed; facts which we attribute to an initial hypertensive episode associated to a left heart failure. The onset of the crisis in two patients was related to known triggering factors: anesthesia and sulpiride. In other two patients associated conditions were diagnosed: medullary carcinoma of the thyroid gland in one of them, and cystic necrosis of the middle layer of the aorta in the other.

Adult↗
PubMed1978

Response of intramuscular Walker 256 rat tumor to sustained-release cyclophosphamide and ARA-C capsules.

Randomly bred Sprague-Dawley rats with the intramuscular form of Walker 256 tumor growing in the right thigh region were treated with sustained-release cyclophosphamide capsules as well as with cytosine arabinoside capsules. A disk-shaped caps-le was implanted subcutaneously adjacent to the tumor mass. Tumor regression, weight gain, and prolongation of lifespan were observed in animals treated with cyclophosphamide capsules of 10 mg or 20 mg total drug content each. However, the walker 256 intramuscular tumor did not respond to ARA-C capsules implanted, and the animals died at the same rate as the controls, with large ulcerated tumor masses and some metastasis. The in vitro diffusion data of ARA-C capsules is shown. Gross and histological changes associated with cyclophosphamide administered in this manner are reported.

Animals↗
PubMed1977

Effects of subcutaneously implanted sustained-release cyclophosphamide capsules on Walker 256 solid rat tumor.

Complete regression of Walker 256 solid rat tumor was brought about by the subcutaneous implantation of a single sustained-release cyclophosphamide capsule adjacent to the tumor mass. Untreated control animals died within 3 weeks after receiving the tumor with large necrotic masses. Rats with sustained-release capsules experienced complete tumor regression within 28 days. Upon examination, the tissues around the previous tumor mass has regenerated, and no viable tumor cells could be found in the area where the previous tumor mass was. Around the implanted sustained-release cyclophosphamide capsule a fibrous sheath has developed over the 3 weeks it was in situ. This study suggests an alternate means of cytoxic drug administration in the treatment of solid tumors in experimental animals.

Animals↗
PubMedDate not supplied

Topical or oral administration with an extract of Polypodium leucotomos prevents acute sunburn and psoralen-induced phototoxic reactions as well as depletion of Langerhans cells in human skin.

Sunburn, immune suppression, photoaging, and skin cancers result from uncontrolled overexposure of human skin to solar ultraviolet radiation (UVR). Preventive measures, including photoprotection, are helpful and can be achieved by topical sunscreening agents. Polypodium leucotomos (PL) has been used for the treatment of inflammatory diseases and has shown some in vitro and in vivo inmunomodulating properties. Its beneficial photoprotective effects in the treatment of vitiligo and its antioxidant properties encouraged us to evaluate in vivo the potentially useful photoprotective property of natural extract of PL after topical application or oral ingestion. Twenty-one healthy volunteers [either untreated or treated with oral psoralens (8-MOP or 5-MOP)] were enrolled in this study and exposed to solar radiation for evaluation of the following clinical parameters: immediate pigment darkening (IPD), minimal erythema dose (MED), minimal melanogenic dose (MMD), and minimal phototoxic dose (MPD) before and after topical or oral administration of PL. Immunohistochemical assessment of CD1a-expressing epidermal cells were also performed. PL was found to be photoprotective after topical application as well as oral administration. PL increased UV dose required for IPD (P < 0.01), MED (P < 0.001) and MPD (P < 0.001). After oral administration of PL, MED increased 2.8 +/- 0.59 times and MPD increased 2.75 +/- 0.5 and 6.8 +/- 1.3 times depending upon the type of psoralen used. Immunohistochemical study revealed photoprotection of Langherhans cells by oral as well as topical PL. The observed photoprotective activities of oral or topical PL reveal a new avenue in examining the potentially useful field of systemic photoprotection and suggests that PL can be used as adjunct treatment and can make photochemotherapy and phototherapy possibly safe and effective when the control of cutaneous phototoxicity to PUVA or UVB is a limiting factor in such phototherapies.

5-Methoxypsoralen↗
PubMedDate not supplied

Percutaneous adipose tissue biopsy by mini-liposuction for metabolic studies.

BACKGROUND: Large fat-biopsy samples are necessary for extensive simultaneous assays. Subcutaneous adipose tissue is generally obtained either by needle-biopsy aspiration (approximately 1 g) or by open surgical biopsy for larger samples. We propose a reliable technique that permits the removal of large adipose tissue samples percutaneously. METHODS: A vertical 5-mm slit was made in the abdominal skin of 15 obese patients, and a liposuction mini-cannula (10 cm x 3 mm) attached to a 20-mL sterile plastic syringe was inserted. A vacuum was created by withdrawing the syringe plunger and fixing it with a specially adapted clamp. RESULTS: We obtained 3- to 15-g samples of adipose tissue without conspicuous scarring or visible contour changes. A significant correlation between the body mass index and the amount of adipose tissue was observed (r = .50, p < .05). Isolated adipocytes remained highly viable, as evidenced by glucose transport under both basal and maximal insulin-stimulated conditions. The mini-liposuction procedure was fast, and once the mini-cannula was removed from the wound, patients could immediately move about freely. CONCLUSION: The new technique described here for fat biopsy using a mini-cannula is less traumatic than open surgical biopsy, and it permits the removal of larger adipose tissue samples than do the usual biopsy techniques. Furthermore, adipose cells are removed intact, and the simplicity of the method facilitates repeat biopsies.

Adipose Tissue↗
PubMedDate not supplied

Synaptophysinlike immunoreactivity in the Merkel cells of pig-snout skin.

Synaptophysin is a membrane glycoprotein (Mr 38,000) found in small vesicles with clear content. It is present in neurons and in a variety of neuroendocrine cells and neoplasms, including the neuroendocrine carcinoma of the skin (Merkel cell tumor). We report the presence of synaptophysinlike immunoreactivity in normal Merkel cells of the pig-snout epidermis and vibrissae. The immunostaining was primarily localized in the Merkel cell side opposite to the nerve terminal. This fact suggests that in Merkel cells, as well as in other neuroendocrine cells, synaptophysin could occur in small clear vesicles (accumulated in Merkel cells in the side opposite to the neurite) and not in the secretory granules themselves (which are concentrated in the cellular side apposed to the neurite).

Animals↗
PubMedDate not supplied

Effect of hyaluronic acid on corneal haze in a photorefractive keratectomy experimental model.

PURPOSE: To evaluate the ability of topical hyaluronic acid to decrease corneal opacity after excimer laser photorefractive keratectomy (PRK) in hens. METHODS: Twenty-four white hens underwent bilateral 193-nm excimer laser PRK to correct -9.00 D of myopia. One eye received postoperative treatment with topical 1% hyaluronic acid six times daily for 3 days; the other eye received phosphate buffered saline. Slit-lamp evaluation by a masked observer was performed for 6 months after PRK, and electron microscopy was carried out at the end of the study. RESULTS: There were no significant differences in postoperative haze between the eyes treated with hyaluronic acid and those treated with phosphate buffered saline. CONCLUSION: Topical administration of hyaluronic acid had no effect on the development of corneal haze following PRK in hens.

Administration, Topical↗
PubMedDate not supplied

An extract of the fern Polypodium leucotomos (Difur) modulates Th1/Th2 cytokines balance in vitro and appears to exhibit anti-angiogenic activities in vivo: pathogenic relationships and therapeutic implications.

In the present study we show the capacity of an extract of the fern Polypodium leucotomos (PLE) to partially inhibit the production of cytokines showing a Th1 pattern (IL-2, IFN-gamma and TNF-alpha) in human PHA-stimulated peripheral blood mononuclear cells. The percentage of inhibition was 24% for IL-2, 72% for INF-gamma and 53% for TNF-alpha. With regard to Th2 cytokines, the addition of PLE resulted in a significant increase (33%) in IL-10 production. Surprisingly, the production of the inflammatory cytokine IL-6 was completely abolished (100% inhibition) by PLE at all doses tested. In a second experiment in vivo we show that, the topical application of PLE to the skin of hairless albino mice (Skh-1) significantly diminished the mast cell infiltrate as well as the number of blood vessels triggered by chronic ultraviolet B (UVB) irradiation. These data show that PLE moderately inhibits the immunological Th1 responses, thus explaining the immunosuppressive as well as the anti-inflammatory and antioxidant activities reported in other studies carried out with PLE. The clear inhibitory effect on TFN-alpha and IL-6 production strongly suggest that this may be the mechanism by which PLE: (a) inhibits angiogenesis in vivo in the mouse model described here, and (b) prevents Langerhans' cells depletion caused by solar irradiation in humans. Taken together, these data suggest that PLE works through the induction of suppressive/anti-inflammatory cytokines such as IL-10 and/or TGF-beta which in turn appear to allow the partial deactivation of macrophages or other accessory cells. These features suggest that PLE could be useful in the treatment of autoaggressive/inflammatory conditions due to an exacerbation of Th1 responses.

Angiogenesis Inhibitors↗
PubMedDate not supplied

[IgG- and IgA-antibodies to the Epstein-Barr virus in the sera of patients with nasopharyngeal carcinoma in Cuba].

Sera from 24 patients with nasopharyngeal carcinoma (NPC) and from 60 normal subjects were examined for the presence of IgG and IgA antibody to various antigens associated with Epstein-Barr virus (EBV). The results indicate that NPC in Cuba, like in other countries, was accompanied by high titers of EBV-specific IgG antibody the levels of which differed markedly from those in normal subjects. Serological activity of the patients differed depending on the stage of the illness and its duration. Geometric mean antibody titers to the capsid antigen (VCA), D and R components of early antigen (EA) of EBV complex were higher in patients with extensive tumour process (III--IV stages) and in patients with the duration of the disease since the onset less than 3 years. Sera of the most patients contained EBV-specific IgA antibody which were practically completely absent in sera of the control subjects. Alongside with characteristic manifestations of responsiveness to EBV observed by other workers, patients with NPC in Cuba had specific features: higher antibody titers to VCA than in Caucasian subjects in the countries where this disease occurred sporadically, like in Cuba; high levels of antibody to EA, frequently exceeding those in patients with NPC from endemic zones (for instance in Chinese patients); prevalence of EBV-specific antibody to the R component of EA complex.

Adolescent↗
PubMedDate not supplied

Seasonal and diurnal variation of pollen from Gramineae in the atmosphere of Córdoba Spain.

We have carried out a study on the annual and diurnal variation of pollen from the Gramineae family in the atmosphere of Córdoba (Southern Spain) during three consecutive years. This family, according to its high sensitizing capacity and to data from allergologists, is responsible for most of the pollenoses diagnosed in the city. Pollen grains from Gramineae were found to occur in the atmosphere virtually throughout the year, starting in February. Yet, they reach their highest levels in spring, particularly in May and the first fortnight of June. Such levels decrease gradually during the summer and become virtually imperceptible from October. The concentration of pollen grains from Gramineae were found to be positively correlated with the average temperature, and negatively correlated with the average humidity. The diurnal variation pattern of the concentration of pollen grains from this family was rather homogeneous throughout the three years studied, with a marked increase early in the morning, a moderate decrease in the afternoon and stable values throughout the night.

Air↗
PubMedDate not supplied

[Chondrosarcoma of the sinuses: an infrequent tumor].

The case of 69 year old male patient who developed sinusal mesenchymal chondrosarcoma is presented. At the time of diagnosis the tumor had spread into the intracranial cavity, which explains why no surgical treatment was carried out. A combined palliative treatment of chemotherapy and radiotherapy was used which did not improve the course of the tumor. The rare location of this form of tumor is discussed. Also commented on are the therapeutic--both surgical and other modalities (chemotherapy and radiotherapy)--difficulties encountered with this condition, given the little experience accumulated with it and its habitual resistance to the therapeutical regimens employed.

Aged↗
PubMedDate not supplied

[Furosemide in the early diagnosis of acute renal insufficiency in the newborn infant].

The study included 13 infants under one year complaining of acute gastroenteritis and dehydration who were still in oliguria or anuria 6 hours after rehydration was initiated. They were given a single dose of furosemide at the rate of 1 mg/kg and indices of U/P of urea and osmolarity, ratio urea/plasmatic creatinine, urinary volume, natriuresis and evolution of urea plasmatic figures and of creatinine were determined. Four patients showed no response to the diuretic; all of them died and through clinical and histopathologic evaluation they were classified as having acute renal insufficiency (IRA). The nine patients showing response to the drug with an increase of 5 to 30 times the control figure for urine and natriuresis showed an index U/P of urea of 5.52 +/- 3.82, U/P of osmolarity of 1.32 +/- 09, ratio urea/plasmatic creatinine of 58.7 +/- 19.8 and the figures for urea and creatinine in blood turned normal within 2 to 4 days. This was classed as prerenal azotemia (APR). It is thus concluded that furosemide appears to be a good parameter to make an early differentiation of cases with IRA, but that this measure, the same as the rest of the indices cannot show an absolute value since there are important variations in each individual.

Acute Kidney Injury↗