Biomedical subjects

O Bolaños

Publications and source records attributed to O Bolaños.

14 recordsLinked to original sources

PubMed2001

Neuroendocrine differentiation of the LNCaP prostate cancer cell line maintains the expression and function of VIP and PACAP receptors.

The molecular mechanisms involved in differentiation of prostate cancer cells to a neuroendocrine (NE) cell phenotype are not well understood. Here we used the androgen-dependent human prostate cancer cell line LNCaP to perform a systematic and broad analysis of the expression, pharmacology, and functionality of vasoactive intestinal peptide (VIP)/pituitary adenylate cyclase-activating peptide (PACAP) receptors. Reverse transcription polymerase chain reaction experiments, together with pharmacological approaches with a set of specific agonists and antagonists, demonstrated the presence of the three VIP/PACAP receptor subtypes (PAC1, VPAC1, and VPAC2 with a major role for VPAC1, acting through adenylate cyclase (AC) stimulation. An essentially similar pattern was observed by NE differentiated cells (4 days after serum deprivation) in spite of the important morphological changes observed. However, the expression of the prostate-specific antigen (PSA) decreased in NE cells (and increased again by dihydrotestosterone, DHT, treatment). The present demonstration of the induction of NE transdifferentiation in LNCaP cells by increasing concentrations of VIP adds value to previous observations on the role of cAMP in this process, an interesting topic in the comprehension of the molecular changes that are involved in the progression of prostate cancer to androgen independence.

Adenylyl Cyclases↗

PubMed1983

Diet and gastric cancer: nutrition survey in a high-risk area.

A nutrition survey was done in four Colombian villages situated in the rural area of Nariño, previously identified as exhibiting different levels of risk for gastric cancer and its precursor lesions. The survey was based on personal visits by trained interviewers to a random sample of families in each village. The major findings of the survey reflected a higher consumption of fava beans in villages with high indices of gastric cancer risk and a higher consumption of fresh fruits and vegetables in villages where such indices were lower. Excessive salt intake and lower potassium intake in villages with a high risk of gastric cancer were suggested, but further work is required to test this preliminary observation. A generally low intake of animal proteins and a high intake of cereals in Nariño did not discriminate between villages at different levels of risk to gastric cancer and its precursors.

Adolescent↗

PubMed1977

Intestinal function and morphology in strongyloidiasis.

Divergent available information on the capability of Strongyloides stercoralis to cause malabsorption prompted a long-term observation in which the nutritional state of the subjects was carefully defined. In spite of moderate to severe symptoms, well nourished patients, even with segmental jejunitis, did not show malabsorption. All patients presenting this parasitic infection with concomitant malnutrition showed absorptive defects. Abnormal absorption persisted in spite of parasitic cure when malnutrition was not immediately corrected, and disappeared with correction of the malnutrition even if parasitic infection was allowed to continue. The present experience indicates that the malabsorption syndrome seen in some cases of S. stercoralis infection is secondary to the concomitant malnutrition and not to the parasite per se.

Duodenum↗

PubMed1975

Enteropathy in adult protein malnutrition: a review of the Cali experience.

Since 1964, 41 patients with strictly defined, severe primary (dietetic) protein malnutrition have been studied under metabolic ward conditions during prolonged periods, initially on a low (20 g) and later on a high (100 g) protein diet. Clinical, nutritional, hematological, intestinal absorptive and histological studies were performed in the malnourished state, during and after protein repletion. Classical signs and symptoms of malnutrition, lasting for at least 4 months, were present in most patients. Mild diarrhea was frequent. All were normoblastically anemic, hypoproteinemic, and hypocholesterolemic; serum folate values were normal or low but serum B12 values were normal or high. Liver biopsy showed fatty liver in the cases where it was performed. Mild malabsorption was detected in over one-half of the patients, with moderate intestinal radiological abnormalities. Malabsorption was independent of concomitant folate deficiency. All the clinical, absorptive and histological abnormalities reversed with treatment consisting only of a high protein diet. In addition to protein lack, another factor has to be invoked in the pathogenesis of the intestinal abnormalities present in severely malnourished adults from rural areas in the tropics.

Adolescent↗

PubMed1975

Enteropathy in adult protein malnutrition: light microscopic findings.

Light microscopy evaluation of the intestinal abnormalities seen in 35 severely malnourished adults revealed changes which are common to other well-documented enteropathies. These included shortening, widening and fusion of the villi, lost convolution of the nuclear line, and diminished epithelial cell height. With Masson's trichrome stain, dense material was seen to have accumulated in a subepthelial location in villi (as described in other enteropathies), in crypts, and perivascularly around the capillaries of the lamina propria. Two findings however appear to characterize the severely malnourished state: a consistent, significant reduction of intestinal mucosal thickness, and in many cases atrophy of the crypts. Statistical analysis of the total mucosal thickness data does not justify five but rather three histological categories. With protein repletion as the sole therapeutic modality, 17 patients in which adequate biopsy samples were available at its completion showed significant amelioration of the aforementioned histological abnormalities, as well as normalization of their previous absorptive defects. The mild enteropathy of severe protein malnutrition must be considered in the differential diagnosis of malabsorption in a tropical setting.

Adolescent↗

PubMed1975

Enteropathy in adult protein malnutrition: ultrastructural findings.

As part of a comprehensive study in adult patients with severe primary protein malnutrition, jejunal ultrastructural studies have been performed in nine adults in the malnourished state. Malnutrition was severe in all. D-Xylose malabsorption and abnormal fecal fat excretion were present in most. The main ultrastructural abnormalities encountered were: microvillar abnormalities such as shortening, diminished numbers, abnormal positioning, branching, and mesalike fusion of the microvilli; and abnormalities in the lamina propria characterized by deposits of osmiodense material and collagen fibers below the basement membrane of the epithelial cells and of the capillaries. None of the aforementioned findings were noted in our control cases. These ultrastructural alterations of severely malnourished adults are nonspecific, since they have already been described in other enteropathies frequently encountered in the tropics.

Adult↗

PubMed1974