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Biomedical subjects

M Aguilar

Publications and source records attributed to M Aguilar.

At least 73 records · Page 4Linked to original sources
PubMed1996

GH response to GH-releasing hormone (GHRH) in Alzheimer and vascular dementia. Relation with somatostatin cerebrospinal levels.

OBJECTIVE: To clarify the functional state of the somatotropinergic system in patients with Alzheimer's disease (AD) and in patients with vascular dementia (VD) in relation with somatostatin cerebrospinal levels. DESIGN We studied the GH response to GHRH in controls and in AD and VD patients and correlated their responses with somatostatin cerebrospinal levels. PATIENTS: Twelve control subjects and 56 patients, 28 with AD and 28 with VD, were studied. A GHRH test was performed in every case. One hundred mcg of GHRH was administered as a intravenous bolus and blood samples were drawn at -15, 0, 30, 60, 90 and 120 minutes. Cerebrospinal fluid was obtained after lumbar puncture. Measurements of GH and somatostatin were determined by specific radioimmunoassay. RESULTS: The GH response to GHRH exhibited no difference between AD and VD patients (12.2 +/- 2 mcg/l vs 9.9 +/- 1.8). There were 17 AD patients and 16 VD patients with exaggerated GH response to GHRH. There was no difference between cerebrospinal levels of somatostatin (30 +/- 2.1 pg/mL in AD patients vs 42 +/- 2.4 in VD patients), and there was no correlation among GH response to GHRH and cerebrospinal levels. CONCLUSION: In our study we observed no difference between the AD and VD patients in GH response to GHRH and no difference in somatostatin cerebrospinal levels in these patients.

Aged↗
PubMed1995

The impact of previous abdominal surgery on outcome following laparoscopic cholecystectomy.

The first 1000 patients undergoing laparoscopic cholecystectomy (LC) at our institution were reviewed to investigate the impact of previous abdominal surgery on LC. The 454 patients having no previous abdominal surgery (NS) were compared to the 541 patients who had previous surgery (PS). PS patients were older, more likely to be female, and had a higher ASA risk category. PS patients had a higher incidence of wound infection, but in all other parameters of outcome, including operative duration and completion, length of hospitalization, and morbidity, there were no significant differences between PS and NS. When PS patients with previous upper abdominal surgery (PUAS, n = 59) were separately compared to the remainder of the entire patient group (NUAS, n = 936), the PUAS group was found to be older, to be more likely to be male, and to have a higher ASA risk category. PUAS patients had a longer postoperative hospitalization, and an increased incidence of intraoperative, postoperative, and total complications, readmissions to the hospital, and unrelated deaths. We conclude previous lower abdominal surgery has little impact on the outcome of patients undergoing LC while previous upper abdominal surgery is associated with increased morbidity.

Abdomen↗
PubMed1995

[Early gastric cancer as a metachronic or synchronic tumor. Report of 6 cases].

Through a period of 16 years, 108 cases of early gastric cancer (EGC) were diagnosed at Hospital Mexico, a leading teaching hospital of Costa Rica's social security system and the University of Costa Rica. It was found that in four cases, the gastric neoplasia was a second primary tumor, and in the two remaining cases, the EGC developed synchronously to another neoplasm. Two of the four metachronic EGC were preceded by a uterine cervix neoplasm on stage lla; the third one was preceded by a breast adenocarcinoma, and the fourth one by a larynx cancer in a heavy male smoker. The treatment received for the first cancer was radiation therapy only, except for the breast cancer patient in whom surgery was employed as well. One of the patients with uterine cervix cancer developed an epidermoid bronchogenic cancer 17 years after the first tumor and 8 years after her EGC. In the two male patients with synchro tumors, the EGC developed together with a squasmous cell carcinoma of esophagus, and in the remaining one the EGC appeared simultaneously with a peritoneal mesothelioma. It is important to emphasize the presence of radiation therapy in the metachronous tumors, as well as the antecedent of smoking in the patient with three primary cancers, the esophagus one, and the larynx cancer patient.

Aged↗
PubMed1995

Relationship between P-glycoprotein expression and cyclosporin A in kidney. An immunohistological and cell culture study.

P-glycoprotein (P-gp), encoded in humans by the mdr-1 gene, acts physiologically as an efflux pump to expel hydrophobic substances from cells. This glycoprotein is closely related to multidrug resistance in tumor cells and can be modulated by cyclosporin A (CsA). We investigated the relationship between CsA and P-gp in 52 renal allograft biopsies and in cultures of Madin-Darby canine kidney (MDCK) renal tubule cells to determine whether the intrarenal accumulation of CsA or chronic stimulation with the drug modified the expression of P-gp. Expression of P-gp and CsA was analyzed by immunohistochemistry. Immunostaining was evaluated semiquantitatively. Modulation of P-gp in MDCK cells after chronic stimulation with CsA for 7, 30, and 60 days was analyzed by flow cytometry. P-gp and CsA immunostaining in renal post-transplant biopsies showed considerable overlap in all cases (Spearman's test, r = 0.577, P < 0.001). After 7 days in vitro, the number of cells expressing P-gp increased progressively; a further increase in mean fluorescence was found after 60 days (P < 0.001, Student's t-test). Our findings suggest that in non-neoplastic cells, CsA may stimulate P-gp as a mechanism of detoxification. Individual differences in the adaptive responses to glycoprotein may be responsible for the appearance of nephrotoxicity or a CsA-resistant rejection reaction in cases of overexpression on lymphocytes and macrophages.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Secretion of growth hormone and thyroid-stimulating hormone in patients with dementia.

We studied the growth hormone (GH) response to GH-releasing hormone (GHRH) and the thyroid-stimulating hormone (TSH) response to thyrotropin-releasing hormone (TRH) in four groups of patients with dementia and examined whether GH and TSH secretion is altered in patients with Alzheimer's disease. The four groups included those with Alzheimer's disease (n = 28), parkinsonism with dementia (n = 10), progressive supranuclear palsy with dementia (n = 10), and dementia of vascular origin (n = 28). The results showed no differences among the four groups in GH response to GHRH (12.2 +/- 2, 10.7 +/- 2, 8.9 +/- 1.1, and 9.9 +/- 1.9 micrograms/ml, respectively); there was no correlation between GH response to GHRH and sex, stage of the disease, or cerebral atrophy. The proportion of patients with exaggerated, normal, or lower GH response was similar in the four groups in terms of TSH response to TRH (9.2 +/- 0.9, 11.1 +/- 1, 11.1 +/- 1, and 10.3 +/- 1 mU/ml, respectively), nor was there a correlation between TSH response to TRH and sex, stage of the disease, cerebral atrophy, or GH response to GHRH. The proportion of those with exaggerated, normal, or lower TSH response was similar in the four groups. Cerebrospinal somatostatin levels were similar in Alzheimer's disease and vascular dementia patients. These findings indicate that neither GH response to GHRH nor TSH response to TRH provides a useful diagnostic adjunct in Alzheimer's disease patients.

Aged↗
PubMed1994

Pseudocysts of the pancreas, a review of 97 cases.

Pseudocysts represent a relatively common problem in the management of patients with pancreatic disease. In evaluating the outcome of treatment, many authors have failed to differentiate between those pseudocysts that follow an attack of acute pancreatitis and those that occur with established chronic disease. We retrospectively reviewed the outcome of treatment in 97 patients admitted to the University of Virginia Hospital in Charlottesville over a 6-year period with a diagnosis of pancreatitis pseudocyst. In 50 of the 97 patients (52%), the pancreatic pseudocyst followed an attack of acute pancreatitis, and 47 (48%) patients had chronic disease. The mean age at presentation was 48.6 +/- 16.4 years for the entire group. Twenty-four patients (25%) were black, and 73 (75%) were white. Sixty-four patients were male (66%), and 33 were female (34%). Alcohol was the important etiological agent in 30 of the 47 patients with chronic pancreatitis (64%), but only 13 of the 50 patients (26%) with acute pancreatitis. By comparison, gallstones were the precipitating cause in 13 of the 50 patients with acute pancreatitis (26%), but only 5 of the 47 patients (11%) with chronic pancreatitis. Thirty-one patients (32%) were treated by observation, 37 patients (36%) by percutaneous aspiration or drainage, and 46 patients (47%) by surgical drainage or resection. Some patients fell into more than one category. Our findings suggested that many patients with small cysts (less than 6 cm) can be managed by a period of observation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1993

High-performance liquid chromatography of amino acids, peptides and proteins. CXXIX. Ceramic-based particles as chemically stable chromatographic supports.

Porous zirconia based particles have been modified using different derivatisation procedures. The modified particles were characterised in terms of their accessible surface areas and degree of surface coverage of the bounded or physicoated phases utilising the strong and specific adsorption of phosphate ions to the zirconia surface. The hydroxyl group density was determined by a 1H NMR technique. The particles were modified by immobilising different silanes to introduce either hydrophobic ligands or reactive groups onto the zirconia surface. In the latter case, various ligands were then covalently attached to the activated supports. Using this type of modification, n-octadecyl- (C18), carbohydrate- and Cibacron Blue F3GA-modified zirconia particles were produced. Furthermore, polymeric coated particles were prepared either by using polybutadiene or by cross-linking the carbohydrate modified sorbents. The pH stability of the different sorbents were determined in batch experiments and under chromatographic conditions. The leakage of ligands was monitored by UV absorption and by employing radioactively labelled ligands. The performance of the C18 reversed-phase modified zirconia in packed columns was also used as an indicator of changes in the surface chemistry following pH stability tests. The experimental results indicate that the Cibacron Blue F3GA dye-modified sorbent was stable up to pH 10.5, the C18 reversed-phase packing up to pH 13 and the carbohydrate-bonded phase up to pH 12. These investigations substantiate the favourable chemical and physical characteristics anticipated for surface modified zirconias for potential use as chromatographic adsorbents.

Carbohydrates↗
PubMed1993

Red-green flicker resolution as a function of heterochromatic luminous modulation.

Critical fusion frequencies have been evaluated in heterochromatic red-green flicker as a function of red-green luminous modulation defined by mL = (R-G)/(R+G)%, at five different mean luminance levels, two test sizes (2 degrees and 5 degrees) and square wave stimuli. The extreme values mL = +/- 100 correspond to ordinary light-dark flicker (red or green); mL = 0 corresponds to pure chromatic flicker, and any other values correspond to simultaneous luminous and chromatic flicker. To implement the stimuli we have developed a new stimuli generator (AVICO, colour vision analyser) using bicolour LEDs as the light source and electronic control of the luminances and frequencies. The results for any luminance level and both test sizes show a minimum critical fusion frequency in the case of pure chromatic flicker (photometric match condition) and a critical fusion frequency which is slightly higher in the green extreme (mL = -100) than in the red (mL = +100). The shape of the variation between the minimum and the extremes is consistent with the results recently reported by Swanson and the theoretical models for the luminance channel response to heterochromatic flicker.

Color Perception↗
PubMed1993

[Pancoast's syndrome: difficulties in its diagnosis].

We present four patients with pancoast tumor diagnosed between 6 to 13 months after the appearance of symptoms. In three of the patients, the presence of old pulmonary apical fibrous lesions complicated diagnosis by simple radiology. Clinical suspicion of the tumor provided the basis for further complementary explorations which confirmed the apical lesion: TC in two patients and RM in the third. Three patients histological diagnosis was obtained by aspirative transthoracic punction. The late diagnosis resulted in the treatment being purely palliative in three cases. It should be stressed that when presented with persistent shoulder pain, clinicoradiological assessment need to be exhaustive in order to make an early diagnosis.

Adult↗
PubMed1993

[The Griscelli-Prunieras syndrome: a case report].

It is presented a six-year-old girl with silvered hair syndrome, of Griscelli-Prunieras variety; hereditary sickness with regressive autosomic and distinguished by partial albinism and leukocytic alterations. She presented the acute phase of the sickness distinguished by: hepatosplenomegaly, thrombocytopenia, lymphadenopathy generalized, and systematic infection; it is corroborated how a hemophagocytic syndrome; during her evolution developed pancerebellar syndrome. By laboratory were corroborated: decrease phagocytosis, degranulation 0%, decrease of globulins gamma, neutropenia, skin test of PPD and Candidin negatives, there were not find the giant inclusions in bone marrow leukocyte and peripheric blood that are feature of Chediak-Higashi syndrome. Another alteration that was the distribution of mote of melanin on the hair that in the Griscelli-Prunieras syndrome are six times bigger in the Chediak-Higashi syndrome.

Acute Disease↗
PubMed1992

Quantitation of molybdopterin oxidation product in wild-type and molybdenum cofactor deficient mutants of Chlamydomonas reinhardtii.

A simple and reliable procedure of oxidation of molybdenum cofactor (MoCo) from molybdoenzymes by autoclaving samples at 120 degrees C for 20 min yielded a single predominant fluorescent species that could be quantitatively determined by reverse phase high performance liquid chromatography. This method allowed detection and quantitation of molybdopterin in cell-free extracts of the green alga Chlamydomonas reinhardtii. The MoCo oxidation product from C. reinhardtii has the same chromatographic and spectral properties as that of milk xanthine oxidase and chicken liver sulfite oxidase. The oxidized species was also detected in molybdenum cofactor mutants of Chlamydomonas reinhardtii defective at the nit-3, nit-4, nit-5/nit-6 and nit-7 loci, which strongly suggests that active molybdenum cofactor itself is not directly involved in the control of its own biosynthetic pathway.

Animals↗
PubMed1992

Direct transfer of molybdopterin cofactor to aponitrate reductase from a carrier protein in Chlamydomonas reinhardtii.

A Chlamydomonas reinhardtii molybdenum cofactor (MoCo)-carrier protein (CP), capable of reconstituting nitrate reductase activity with apoprotein from the Neurospora crassa mutant nit-1, was subjected to experiments of diffusion through a dialysis membrane and gel filtration. CP bonded firmly MoCo and did not release it efficiently unless aponitrate reductase was present in the incubation mixture. Stability of MoCo bound to CP against air and heat was very similar to that of free-MoCo released from milk xanthine oxidase. Our data strongly suggest that MoCo is directly transferred from CP to aponitrate reductase to form an active enzyme.

Animals↗
PubMed1992

Laparoscopic cholecystectomy in the obese patient.

The authors' experience with laparoscopic cholecystectomy (LC) in obese (O, n = 96) and morbidly obese (MO, n = 27) patient groups was compared with that in the normal weight (NW, n = 174) group of patients as well as the whole group (WG). There were no operative deaths. There were no significant differences between groups for any of the following: successful intraoperative cholangiography (WG, 52.2%; NW, 52.9%; O, 51.1%; MO, 55.6%), conversion to open cholecystectomy (WG, 9.6%; NW, 9.2%; O, 10.4%; MO, 11.1%), incidence of major complications (WG, 4.1%; NW, 3.4%, O, 5.2%; MO, 0%), incidence of minor complications (WG, 7.4%, NW, 7.5%; O, 6.3%; MO, 3.7%), and length of hospitalization after successful LC (WG, 1.25 days; NW, 1.31 days; O, 1.16 days; MO, 1.13 days). Duration of operation did not differ except LC in the MO group (136.4 +/- 6.9 minutes) was longer when compared with NW patients (123.0 +/- 2.9 minutes, p less than 0.05). The authors conclude LC is a safe and effective treatment for obese patients with symptomatic cholelithiasis.

Adult↗
PubMed1991

[Pleural effusion and constrictive pericarditis secondary to bromocriptine treatment].

The case of a 60 year old patient with Parkinson's disease is reported, who, following 2 years of treatment with bromocriptine, presented a left pleural effusion in which chronic constrictive pericarditis was demonstrated. Studies aimed at establishing the etiology were negative. Upon withdrawal of bromocriptine, the pleural effusion disappeared and the patient remained asymptomatic, with only pleural thickening persisting in the thoracic radiography. The appearance of polyserositis as an undesirable effect of the use of bromocriptine is discussed. The first case associated to chronic pericarditis is reported.

Bromocriptine↗
PubMed1990

Standard breakfast test: an alternative to glucagon testing for C-peptide reserve?

We measured C-peptide after glucagon and breakfast tests to compare the effectiveness of both tests in evaluating residual beta cell function in normal and diabetic subjects. A significantly higher C-peptide response was elicited after standard breakfast in patients with insulin-dependent diabetes mellitus of less than two years' evolution, ranging from 0.12 +/- 0.07 to 0.83 +/- 0.18 ng/ml (P less than 0.05). In nonobese noninsulin-dependent diabetes mellitus the response ranged from 0.86 +/- 0.02 to 1.89 +/- 0.48 ng/ml (P less than 0.0025); in obese NIDDM from 1.02 +/- 0.37 to 1.55 +/- 0.46 ng/ml (P less than 0.05), and in normal subjects from 0.77 +/- 0.23 to 2.11 +/- 1.22 ng/ml (P less than 0.0025). We conclude that the standard breakfast test is a useful and practical approach to the study of residual beta cell function.

Adolescent↗