PubMed Health⌕ Search

Biomedical subjects

A Vargas

Publications and source records attributed to A Vargas.

At least 19 recordsLinked to original sources
PubMed1997

Effect of single point mutations of the human tachykinin NK1 receptor on antagonist affinity.

Molecular modelling and site-directed mutagenesis were used to identify eleven amino acid residues which may be involved in antagonist binding of the human tachykinin NK1 receptor. Recombinant receptors were expressed in mammalian cells using the Semliki Forest virus system. Wild type and mutant receptors showed similar expression levels in BHK and CHO cells, verified by metabolic labelling. Binding affinities were determined for a variety of tachykinin NK1 receptor antagonists in SFV-infected CHO cells. The binding affinity for GR203040, CP 99,994 and CP 96,345 was significantly reduced by mutant Q165A. The mutant F268A significantly reduced the affinity for GR203040 and CP 99,994 and the mutant H197A had reduced affinity for CP 96,345. All antagonists seemed to bind in a similar region of the receptor, but do not all rely on the same binding site interactions. Functional coupling to G-proteins was assayed by intracellular Ca2+ release in SFV-infected CHO cells. The wild type receptor and all mutants except A162L and F268A responded to substance P stimulation.

Animals↗
PubMed1997

Calcium pyrophosphate dihydrate crystal deposition disease presenting as a pseudotumor of the temporomandibular joint.

We report a case of a 66-year-old white woman with calcium pyrophosphate dihydrate (CPPD) crystal deposition disease. The patient related a 2-month history of swelling with tenderness over the left pre-auricular region. A CT scan suggested a synovial chondromatosis. Surgical removal was done and histologic study showed CPPD crystals. This disease rarely involves the temporomandibular joint (TMJ) and is not usually considered in the differential diagnosis. To our knowledge, only 14 cases have been reported in the literature.

Aged↗
PubMed1995

Functional activity of a biotinylated human neurokinin 1 receptor fusion expressed in the Semliki Forest virus system.

The 1.3 S biotinylatable subunit of Proprionibacterium shermanii transcarboxylase complex was fused to the C-terminus of the human neurokinin 1 receptor gene and introduced into the Semliki Forest virus expression vector pSFV1. RNA transcribed from pSFV1-NK1-biot and pSFV-Helper2 was coelectroporated into BHK cells permitting in vivo packaging of recombinant virus. Infection of BHK and CHO cells with SFV-NK1-biot virus yielded high level of the fusion receptor as detected by metabolic labeling, immunoblotting with streptavidin alkaline phosphatase and binding to substance P. Like native receptor, the biotinylated receptor fusion was able to stimulate Ca2+ mobilization in infected CHO cells, indicating functional coupling to guanine-nucleotide-binding proteins.

Animals↗
PubMed1995

Role of metallothionein and cysteine-rich intestinal protein in the regulation of zinc absorption by diabetic rats.

Hyperzincuria and low Zn absorption in diabetic animals and humans have prompted speculation that diabetics are more susceptible to Zn deficiency. There is little information, however, describing the effects of diabetes on the biochemical mechanisms of intestinal Zn transport. We evaluated Zn absorption in streptozotocin-induced diabetic rats based on a model of Zn transport in which cysteine-rich intestinal protein serves as an intracellular carrier that is inhibited by metallothionein (MT). Apparent absorption and retention of Zn and Cu in rats fed a purified diet were measured in a balance study 15-17 d after induction of diabetes. The rate of 65Zn absorption from isolated intestinal segments, molecular distribution of 65Zn in mucosal cytosol, and tissue MT levels were measured on d 20-22. Food consumption, and thus Zn and Cu intake, by diabetic rats was twice that of controls. Although fractional absorption (percent) of Zn and Cu was lower in the diabetic rats, net absorption (micrograms/100 g body weight/d) was higher. The higher net absorption in the diabetic group was offset, however, by higher urinary excretion, so that Zn and Cu retention was similar in both groups of animals. Low fractional absorption is attributable to the down-regulation of intestinal Zn transport, as indicated by the lower rate of 65Zn absorption from isolated intestinal segments in the diabetic rats. Down-regulation of intestinal transport is in turn attributable to higher concentrations of intestinal MT, which resulted in more 65Zn in the mucosal cytosol bound to MT, an inhibitor of Zn transport, and less to cysteine-rich intestinal protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Citrate inhibition of rat-kidney cortex phosphofructokinase.

The regulatory properties of citrate on the activity of phosphofructokinase (PFK) purified from rat-kidney cortex has been studied. Citrate produces increases in the K0.5 for Fru-6-P and in the Hill coefficient as well as a decrease in the Vmax of the reaction without affecting the kinetic parameters for ATP as substrate. ATP potentiates synergistically the effects of citrate as an inhibitor of the enzyme. Fru-2,6-P2 and AMP at concentrations equal to Ka were not able to completely prevent citrate inhibition of the enzyme. Physiological concentrations of ATP and citrate produce a strong inhibition of renal PFK suggesting that may participate in the control of glycolysis in vivo.

Adenosine Triphosphate↗
PubMed1994

Oxidant-mediated ciliary dysfunction in human respiratory epithelium.

Exposure of human nasal ciliated epithelium to reactive oxidants generated by the enzymatic xanthine-xanthine oxidase superoxide/hydrogen peroxide (H2O2) and glucose-glucose oxidase H2O2-generating systems, or to reagent H2O2 or hypochlorous acid (HOCl) resulted in significant alterations in ciliary beating. The earliest change noted was the presence of ciliary slowing, progressing eventually to complete ciliary stasis in some areas. Ciliary dyskinesia was seen within the first hour, often from as early as 15 min after exposure of the cells to reactive oxidants. Using peroxidases, various antioxidant enzymes, and oxidant scavengers, we confirmed that these detrimental effects on ciliary function were mediated primarily by H2O2 and HOCl. Moreover, 3-aminobenzamide (3-ABA), an inhibitor of the DNA repair enzyme poly ADP ribose polymerase, prevented H2O2-mediated inhibition of ciliary function, indicating that oxidant-mediated damage to DNA may well be the basis of the effects of H2O2 on ciliated epithelium. Acute and chronic inflammatory responses may therefore present the possible threat of H2O2- or HOCl-inflicted injury on bystander respiratory epithelium, leading to ciliary dyskinesia and slowing.

Catalase↗
PubMed1994

Spontaneous pneumothorax. Long-term results with tetracycline pleurodesis.

The aim of this prospective study was to determine the rate of recurrence for spontaneous pneumothorax (SP) after tetracycline pleurodesis (TCP), using that of observation, tube thoracostomy alone, and thoracotomy as references. From 1985 to the end of 1991, 78 patients were treated with tetracycline pleurodesis and 135 patients served as control subjects. Pleurodesis was induced by instillation of tetracycline and ascorbic acid through the pleural drain. The indication was any SP treated with tube thoracostomy, without active pulmonary infection. Follow-up period was from 13 to 95 months (mean, 45 months); follow-up rate was 94 percent. Post-therapy surgery was necessary for eight patients in whom pleurodesis failed due to presence of a persistent air leak. The ipsilateral recurrence rate of patients treated with TCP was 9 percent (6/66) and recurrence time ranged from 2 days to 9 months. The recurrence rate for patients treated with observation was 36 percent, 35 percent for those having chest tube alone, and none for those undergoing surgery. No death occurred as a direct result of this procedure and all patients could be released from the hospital. Eleven subjects died during the follow-up period; the mean follow-up until death was 37 months (range, 2 to 87 months). Five deaths were due to respiratory causes and six were due to extrapulmonary causes. Tetracycline pleurodesis has been shown to be a good alternative for the prevention of recurrence of SP. Its recurrence rate is lower than that of tube drainage but higher than that of surgical treatment.

Adolescent↗
PubMed1993

Recent advances in the treatment of childhood obesity.

The multidisciplinary, four-phase approach, which includes PSMF, BEM, and MPE is successful in treating mild, moderate, and severe degrees of childhood and adolescent obesity. The MPE program is appropriate for use with PSMF and BEM due to its progressive nature, variety of options, and moderate intensity level. In addition, the MPE program is of sufficient intensity, duration, and frequency to promote a significant increase in estimated aerobic capacity (VO2max) and to promote the maintenance of lean body mass and resting energy expenditure. The short-term intervention of PSMF, BEM, and MPE also results in an improvement in body composition, lipid profiles, and IGF-1 and T3 levels. The 1200-calorie balanced diet, MPE, and BEM also provide a successful method of weight maintenance in children and adolescents, as indicated by further improvement in body composition at the 26-week measure. Additional studies are needed to assess the contribution of exercise to the maintenance of lean body mass and resting energy expenditure in obese children and adolescents. In addition, it will be important to assess long-term weight maintenance in obese adolescents who effectively lose weight in this multidisciplinary program.

Adolescent↗
PubMed1993

Circannual inter-relationships among reproductive hormones, gross morphometry, behaviour, ejaculate characteristics and testicular histology in Eld's deer stags (Cervus eldi thamin).

Blood samples, morphometric measurements and behavioural data were collected weekly for 52 weeks from six adult Eld's deer stags exposed to natural fluctuations in photoperiod (38 degrees N latitude). Mean (+/- SEM) serum LH concentrations reached peak values in the autumn (October), three months before FSH and testosterone concentrations reached peak values in early winter (January). Prolactin concentrations were inversely related (r = -0.733, P < 0.001) to LH and directly related to daylength, and maximal concentrations were observed during mid-summer (July) and minimal concentrations during early winter (January). The temporal pattern of circulating inhibin was positively correlated with FSH (r = 0.88, P < 0.001), but lagged behind the seasonal FSH increase by 1-3 weeks. Antler length, body weight and chest girth were maximal during pre-rut (December-January). Maximal scrotal circumference and combined testes volume were observed in mid-winter (February), whereas peak neck girth and behavioural aggression occurred 1-3 months later (March-May). On the basis of quarterly electroejaculation results, motile spermatozoa were produced in all seasons. However, the greatest number of motile spermatozoa per ejaculate was observed during the winter and spring, whereas the highest incidence of sperm pleiomorphisms (> 80%) was detected in the autumn. Histological assessments of the regressed testis (July) revealed fewer germ cells undergoing spermatogenesis and an increased incidence of degenerating and abnormal cell types. In summary, Eld's deer exhibit a circannual hypothalamic-pituitary-gonadal cycle with onset of pituitary activation occurring during the autumn and winter, whereas gonadal activity peaks during the winter and spring as daylengths are increasing. Marked circannual variations in circulating prolactin suggest that Eld's deer may use photoperiodic cues to modulate seasonal fertility; however, the existence of an endogenous seasonal rhythm operating independently of photoperiod cannot be excluded.

Animals↗
PubMed1993

Seasonal patterns of basal and GnRH-induced LH, FSH and testosterone secretion in Eld's deer stags (Cervus eldi thamin).

Plasma LH, FSH and testosterone were measured in blood samples collected via remote catheterization from six adult Eld's deer stags every 10 min for 8 h before and 2 h after GnRH (1 microgram kg-1, i.v.) administration. Blood samples were collected within 2 weeks of the summer solstice (21 June), autumn equinox (22 September), winter solstice (21 December) and spring equinox (20 March). Marked seasonal variations in basal LH, FSH and testosterone concentrations were observed. From autumn, well-defined LH pulses were temporally associated with small, but detectable pulses in testosterone. During the winter transition into the breeding season, episodic LH pulses were also temporally associated with corresponding testosterone surges that lasted 2-3 h. High amplitude, low frequency testosterone surges were also observed during the spring, but often in the absence of detectable LH pulses. Basal LH and testosterone concentrations decreased during the summer and, although LH pulses were detected, associated testosterone pulses were absent. Only 37% of LH pulses occurred coincidentally with FSH pulses, and FSH pulses were generally less prominent. The increases in LH and FSH above basal concentrations after GnRH treatment were significant (P < 0.05) for all seasons. Increases in testosterone after GnRH treatment were greatest during the winter and spring, but testosterone also increased to a lesser extent during the autumn (P < 0.05). In contrast, testosterone concentrations were not different before and after GnRH treatment during summer.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Immunocytochemical detection of amylase, carboxypeptidase A, carcinoembryonic antigen and alpha 1-antitrypsin in carcinomas of the exocrine pancreas of the dog.

The immunocytochemical detection of amylase, carboxypeptidase A, alpha 1-antitrypsin, carcinoembryonic antigen (CEA) and keratin in normal canine pancreatic tissue and in carcinomas of the exocrine pancreas of the dog is described. In the normal pancreas, the acinar cells contain amylase, carboxypeptidase and alpha 1-antitrypsin. The pancreatic ducts react with the antikeratin antibody. Twelve out of 14 pancreatic exocrine carcinomas showed immunoreaction with antiamylase antibody, and 10 with anticarboxypeptidase antibody. Five neoplasms reacted with anti-CEA antibody and three with the anti-alpha 1-antitrypsin antibody. It was not possible to find any systematic difference in the immunocytochemical profiles of acinar, tubular and undifferentiated carcinomas. These results indicate that immunocytochemical marking of amylase and carboxypeptidase is of value in the diagnosis of pancreatic neoplasms in the dog, especially if metastasis is the only material available for study and the tumour does not show any diagnostic feature on routine light microscope preparations.

Adenocarcinoma↗
PubMed1992

Photoprotective effects of sunscreens in cosmetics on sunburn and Langerhans cell photodamage.

It has become common practice to add sunscreening agents of variable potency to cosmetics to protect against the adverse effects of ultraviolet (UV) radiation exposure. The purpose of this study was to determine whether cosmetic preparations containing sunscreening agents protected against the adverse effects of acute UV radiation exposure and, if so, to identify the components responsible for the photoprotective effects. Pretreatment of skin with one such cosmetic product provided complete protection against UV-induced erythema, sunburn cell formation and Langerhans cell damage in volunteers, skin types II and III, whose skin was exposed to a 1.5 minimal erythema dose daily for 4 consecutive days. When individual components of the cosmetic preparation were analyzed for their photoprotective activities, it was found that both the cinnamate and benzophenone sunscreen combination and an extract of baker's yeast present in the preparation had photoprotective properties. These studies indicate that incorporation of photoprotective agents into cosmetic preparations provides a beneficial function and should therefore be encouraged.

Adolescent↗
PubMed1991

Pathological changes in the lungs and mammary glands of sheep and their relationship with maedi-visna infection.

Maedi-visna, a multisystemic disease of adult sheep, was first described in Spain in 1984. To get an idea of the seroprevalence of the disease locally and to estimate the number of seropositive animals with lesions, samples of blood, lungs and mammary glands were taken from 124 randomly selected sheep killed in the main slaughterhouse of Zaragoza. In the agar gel immunodiffusion test, 74 (59.7 per cent) of the sheep were positive and 50 were negative. Among the 74 seropositive animals, 19 (25.6 per cent) had no lesions in any organ, 12 (16.2 per cent) had lesions in the lungs only, 15 (20.2 per cent) had lesions in the mammary glands and 28 (37.8 per cent) had lesions in both organs. In the lungs hyperplasia of lymphoid follicles was more evident than an interstitial infiltrate but in the mammary glands this relationship was not observed. Even when the lesions occurred in both organs, they did not show the expected proportion in terms of either type or severity. Among the 50 seronegative sheep, eight (16 per cent) showed maedi-like lesions, formed exclusively by the hyperplasia of lymphoid follicles.

Animals↗
PubMed1991

Canine leishmaniasis associated with systemic vasculitis in two dogs.

Two cases of canine leishmaniasis associated with systemic necrotizing vasculitis are described. The main macroscopic lesions were haemorrhagic in type; histopathological changes confirmed a vascular lesion affecting small arteries of several organs (skin, intestinal tract, kidney, urinary bladder, mesenteric lymph nodes, adrenal gland, myocardium, lung, eye and choroid plexus). The presence of the parasite was confirmed with a specific immunocytochemical stain. The possibility of an immunological aetiology of the vasculitis and its classification is discussed.

Animals↗
PubMed1987

Primary malignant fibrous histiocytoma of the mandible: surgical approach and report of a case.

A case of histologically proven malignant fibrous histiocytoma (MFH) of the mandible is presented. This tumor rarely occurs as a primary neoplasm of the mandible. An intraoral block resection of the mandible, including adjacent clinically normal soft tissue was performed. To maintain the soft tissue bed and esthetics, and to preserve mandibular function, immediate reconstruction was carried out with methyl methacrylate, the anatomical configuration of which was derived from the resected specimen.

Female↗
PubMed1986

Hypercalciuria, hyperphosphaturia, and growth retardation in children with diabetes mellitus.

The role of hypercalciuria and hyperphosphaturia in the growth retardation of children with diabetes mellitus was investigated in 157 children with diabetes whose mean height was less than that of 37 nondiabetic siblings of similar age (P less than .025). Hyperglycemia, hypercalciuria, and hyperphosphaturia were assessed coincident with the height measurement of each child in a cross-sectional survey. The distribution of height percentiles of the children with diabetes was skewed to the left with 61% at or below the 50th percentile. Eleven percent of the insulin-dependent children with diabetes mellitus were shorter than would be anticipated by a normal distribution of the 157 children. The duration of diabetes (hyperglycemia) had the greatest influence upon the children's height. Children with diabetes were shorter than the nondiabetic subjects by the fourth year of hyperglycemia, and this difference in height became statistically significant after 7 years or more of diabetes. The degree of hypercalciuria and hyperphosphaturia was more closely associated with reduced height in children with diabetes than was the degree of hyperglycemia, although the renal wastage of calcium and phosphorus seemed to be the result of glucosuria. Because hypercalciuria and hyperphosphaturia impair growth in nondiabetic children, they may also play an important role in the poor growth of children with diabetes mellitus.

Adolescent↗