PubMed Health⌕ Search

Biomedical subjects

M Castillo

Publications and source records attributed to M Castillo.

At least 19 recordsLinked to original sources

Postnatal developmental changes in CO2 sensitivity in rats.

Ventilatory sensitivity to CO(2) in awake adult Brown Norway (BN) rats is 50-75% lower than in adult Sprague-Dawley (SD) and salt-sensitive Dahl S (SS) rats. The purpose of the present study was to test the hypothesis that this difference would be apparent during the development of CO(2) sensitivity. Four litters of each strain were divided into four groups such that rats were exposed to 7% inspired CO(2) for 5 min in a plethysmograph every third day from postnatal day (P) 0 to P21 and again on P29 and P30. From P0 to P14, CO(2) exposure increased pulmonary ventilation (Ve) by 25-50% in the BN and SD strains and between 25 to over 200% in the SS strain. In all strains beginning around P15, the response to CO(2) increased progressively reaching a peak at P19-21 when Ve during hypercapnia was 175-225% above eucapnia. There were minimal changes in CO(2) sensitivity between P21 and P30, and at both ages there were minimal between-strain differences. At P30, the response to CO(2) in the SS and SD strains was near the adult response, but the response in the BN rats was 100% greater at P30 than in adults. We conclude that 1) CO(2)-sensing mechanisms, and/or mechanisms downstream from the chemoreceptors, change dramatically at the age in rats when other physiological systems are also maturing ( approximately P15), and 2) there is a high degree of age-dependent plasticity in CO(2) sensitivity in rats, which differs between strains.

Administration, Inhalation↗

Scarce influence of corticosteroid boluses on long-term viral load and liver histology in transplanted patients with recurrent hepatitis C.

Corticosteroid boluses, which are the treatment for acute rejection episodes, have been shown to produce transient increases in viremia. However, their effect on long-term viral load, histological activity index (HAI), and fibrosis has not been well established. The aim of our study was to compare late viral load, HAI, and fibrosis in patients with versus without steroid boluses in the immediate posttransplant period. We analyzed patients transplanted due to hepatitis C virus. Inclusion criteria were: no change in immunosuppression (cyclosporine or tacrolimus with/without mycophenolate); no steroids in the previous 4 months; no antiviral treatment; liver biopsy and viral load determination >12 months after transplantation. Exclusion criteria were HIV, hepatitis B, and active cytomegalovirus infection. Nonparametric tests were used to compare viral load, HAI, and fibrosis (Ishak-score) among patients who received steroid boluses for an acute rejection episode (group 1) versus those who did not (group 2). Among the 48 selected patients were 38 men with the overall mean age of the entire group of 55.6 +/- 10.9 years. The mean period from liver transplantation was 53.25 +/- 33.4 months. Thirty-four (70.1%) were treated with tacrolimus and the rest, cyclosporine. Eleven (22.9%) had and 37 (77.1%) had not received corticosteroid boluses. The viral load was similar in groups 1 and 2 (5.74 +/- 0.54 vs 5.98 +/- 0.53 Log(10) IU per mL, P = .32). Fibrosis was also similar (2.5 +/- 1.6 vs 2.2 +/- 1.7, P = .56). However, HAI was higher in group 1 (7.5 +/- 1.7 vs 6.0 +/- 1.7, P = .026). In conclusion, although long-term viral load was similar in patients who had versus had not received one cycle of steroid boluses, the HAI was significantly higher in the former cohort, but had not resulted in greater fibrosis during the study follow-up.

Adrenal Cortex Hormones↗

Hepatitis C virus recurrence after liver transplantation: influence of immunosuppressive regimens on viral load and liver histology.

Cyclosporine has recently been reported to produce in vitro suppression of hepatitis C virus replication driven by blockade of cyclophilins, an effect not shown for tacrolimus. However, the clinical consequence of this in vitro finding have not been well studied in vivo. We compared viral load and fibrosis in transplanted patients receiving monotherapy with tacrolimus or cyclosporine. Patients with recurrent hepatitis C after transplantation were selected from two tertiary centers with the following inclusion criteria: monotherapy with tacrolimus or cyclosporine for more than 12 months before viral load measurement, no antiviral treatment, corticosteroids stopped within 12 months after transplantation. HIV, hepatitis B, and active infection by cytomegalovirus were excluded. Patient characteristics, viral load, and fibrosis were compared by univariate analysis between the cyclosporine and tacrolimus groups. Significant variables, viral load, and fibrosis were included in a multivariate model. Sixty-six patients were included, 46 on tacrolimus and 20 on cyclosporine. Fifty-six were male, and the mean age was 55.3 +/- 10.1 years. Fibrosis (Ishak score) was 3.9 +/- 1.9 in the cyclosporine group and 2.7 +/- 1.9 in the tacrolimus group (P = .019). Viral load (log(10)IU/mL) was 5.8 +/- 0.5 and 5.9 +/- 0.5, respectively (P = .7) and time since liver transplantation was 95.3 +/- 47.7 and 41.1 +/- 16.8 months (P = .0001). In the multivariate model, viral load (P = .65) and fibrosis (P = .24) were not significantly different and only time since transplantation remained significant (P = .0001). In conclusion, viral load was not different in patients with tacrolimus as compared with cyclosporine, and the lower fibrosis observed in the cyclosporine group lacked significance when considered together with time since liver transplantation.

Aged↗

Fibrous Histiocytoma-like Spindle-Cell Proliferation in the Nipple After Body-Piercing.

We report the case of a 19-year-old pregnant woman who presented with a nipple tumor. The lesion consisted in a spindle-cell proliferation with histologic features similar to those of fibrous histiocytoma, with a highly vascularized stroma. Although it showed low mitotic activity, scattered marked atypical cells with prominent nucleoli were identified, thus raising concern about the benign nature of the tumor. Immunohistochemical evaluation revealed that the spindle cells were diffusely positive for vimentin, focally positive for CD68, and negative for all the other tested antibodies. The patient had a total excision of the lesion and she is free of disease after 30 months. To our knowledge this is the first reported case of a lesion of this type in the nipple after body-piercing.

Adult↗

Nutritional control, gene regulation, and transformation of vascular smooth muscle cells in atherosclerosis.

Contractile-state smooth muscle cells (SMC), the only cell type in the arterial media, undergoes migration to the intima, proliferation, and abundant extracellular matrix production during the early stages of atherosclerosis. This involves the ingestion of low-density lipoprotein (LDL) and modified or oxidised LDL by macrophages together with SMC by several pathways including a scavenger pathway leading to accumulation of cholesterol esters and formation of foam cells. High-plasma cholesterol levels constitute a major causative risk for atherosclerosis. The membrane-bound transcription factor called sterol regulatory element binding protein (SREBP) activates gene-encoding enzymes of cholesterol and fatty acid biosynthesis. The SREBP expression, in response to diet, shows that are involved in both lipogenesis and cholesterol homeostasis, moreover SREBPs are regulated directly by cholesterol. Animal models were used in trials of atherosclerosis, and cholesterol feeding has been described elsewhere as producing atherosclerotic lesions. We have examined the morphological, molecular and proliferative change in arterial SMC mimicking such a cholesterol diet, this transformed SMC is a good model to study the alterations of the differentiated state of SMC, and the transformation into foam cell, caused by cholesterol-rich diet. Despite the complexity of the interactions in atherosclerosis, there are many opportunities to affect the homeostatic balance of the artery wall at SMC levels. We have considered here some of the possible targets for intervention with promising strategies for the nutritional control of the genes, and, in a general way, the possibilities for modulating the expression of genes influencing atherosclerosis.

Animals↗

The response of gastrointestinal microbiota to avilamycin, butyrate, and plant extracts in early-weaned pigs.

An experiment was designed to evaluate the effects of 3 different additives on the gastrointestinal microbiota of early-weaned pigs. Early-weaned (18 to 22 d; n = 32) pigs (6.0 +/- 0.10 kg of BW) from 8 litters were randomly distributed into 8 pens. Each pen was assigned 1 of 4 dietary treatments: a prestarter or control diet, the control diet with 0.04% avilamycin (AB), with 0.3% sodium butyrate, or with 0.03% plant extract mixture (XT; standardized mixture with 5% (wt/wt) carvacrol extracted from Origanum spp., 3% cinnamaldehyde extracted from Cinnamonum spp., and 2% capsicum oleoresin from Capsicum annum). At the end of the experimental period, 8 pigs per treatment were killed, and samples of their intestinal content were taken. The total bacterial load along the gastrointestinal tract (GIT; stomach, jejunum, cecum, and distal colon) and the lactobacilli and enterobacteria in the jejunum and cecum were measured by quantitative PCR. The total microbial counts along the GIT did not differ among the diets, but there was an increase in the lactobacilli:enterobacteria ratio in the cecum of the piglets on the XT diet (P = 0.003). Restriction fragment length polymorphism of the PCR-amplified V3, V4, and V5 regions of the 16S rDNA gene showed changes in the structure of the microbial community in the jejunum. Dendrograms grouped animals by diets; control with 0.3% sodium butyrate was the treatment that promoted the biggest changes in the microbial ecosystem, followed by AB and then XT. Biodiversity increased when using additives compared with the control diet (P = 0.002). Microbial metabolic activity along the hindgut was studied using the concentration of purine bases and carbohydrase activities. Different patterns for purine bases were observed between diets (diet x intestinal section, P = 0.01). The control diet reached a maximum purine base concentration at the end of the colon, whereas that of the AB diet was reached at the cecum. We could not detect any cellulase or xylanase activities in animals of this age. Appreciable amylase and amylopectinase activities were found, but they did not differ between diets. The results suggest that the effects of avilamycin, butyrate, or the plant extract would not be related to a reduction in the number of total bacteria inhabiting different sections of the GIT but rather to changes in the ecological structure and metabolic activity of the microbial community.

Animal Feed↗

Effects of butyrate, avilamycin, and a plant extract combination on the intestinal equilibrium of early-weaned pigs.

We evaluated the effects of 3 additives, sodium butyrate (AC), avilamycin (AB), and a combination of plant extracts (XT), on the productive performance and the intestinal environment of the early-weaned pig. The XT was a standardized mixture with 5% (wt/wt) carvacrol (from Origanum spp.), 3% cinnamaldehyde (from Cinnamonum spp.), and 2% capsicum oleoresin (from Capsicum annum). Pigs (n = 32) weaned at 18 to 22 d of age with an initial BW of 6.0 +/- 0.10 kg were allocated to 8 pens that, in turn, were allocated to 4 treatments. The treatments included a basal diet (CT) or the basal diet supplemented with 0.3% of AC, 0.04% of AB, or 0.03% of XT. Productive performance was determined during the initial 14 d postweaning. On d 19 and 21 of the experiment, the pigs were killed to allow collection of digesta and intestinal tissue to evaluate variables indicative of aspects of the gastrointestinal environment. Treatments AB and AC improved G:F (P = 0.012 and 0.003, respectively) compared with the CT. Butyrate included in the diet was only detected in the stomach but not in cranial jejunum. When compared with CT, AC produced a lower ileal starch digestibility (P = 0.002) and a lower whole-tract OM and starch digestibility (P = 0.001 and 0.003, respectively), related to a lower VFA concentration in the cranial colon (P = 0.082) and a numerically reduced branched VFA percentage in the rectum. The AB treatment diminished propionate production in caudal colon (P = 0.002) and rectum (P = 0.012) compared with CT. The AC group exhibited deeper crypt depth in the jejunum without variations in villus height compared with CT (P = 0.042). The AC and AB groups also increased goblet cell presence in the colon (P = 0.001 and 0.032, respectively). On the other hand, AB and XT diminished intraepithelial lymphocytes in the jejunum (P = 0.003 and 0.034, respectively). The XT increased lymphocyte presence in the colon (P = 0.003). These results show the important influence of AB and AC on productive performance and on pig gut dynamics. The intestinal modifications observed for AB and AC compared with CT suggest distinct modes of action for each additive.

Animal Feed↗

Low-pressure DC air plasmas. investigation of neutral and ion chemistry.

The neutral and charged species present in a direct current (dc) hollow cathode, gas flow, air reactor are experimentally studied by quadrupole mass spectrometry. The degree of ionization of the plasma and the electron mean temperature with decreasing air pressure, for constant discharge current, are measured with a double Langmuir probe. The chemical composition of the plasma changes appreciably over the 3 x 10(-3) to 5 x 10(-2) mbar range investigated: at the lowest pressures studied, O2 dissociation is up to 60% and the concentration of NO is half that of N2; concerning ions, NO+ and N2+ are dominant for the whole pressure range. A kinetic model of the plasma including electrons, neutrals, and positive ions is developed to account for the experimental observations; it is consistent with energy balance and predicts that heterogeneous processes are the main source of NO and that the contribution of ions to the global chemistry of neutrals is of minor significance even for the lowest pressures.

Air↗

Diode laser spectroscopy of the fundamental bands of 12C14N, 13C14N, 12C15N, 13C15N free radicals in the ground 2 Sigma+ electronic state.

Rotationally resolved spectra of the fundamental band of the CN free radical in four isotopic forms have been measured using tunable diode laser absorption spectroscopy. The source of the radical was a microwave discharge in a mixture of isotopically selected methane and nitrogen diluted with argon. The lines were measured to an accuracy of 5 x 10(-4) cm(-1) and fitted to the formula for the vibration rotation spectrum of a diatomic molecule, including quartic distortion constants. The band origins of each of the isotopomers from the five parameter fits were found to be 12C14N: 2042.42115(38) cm(-1), 13C14N: 2000.08479(23) cm(-1), 12C15N: 2011.25594(25) cm(-1), 13C15N: 1968.22093(33) cm(-1) with one standard deviation from the fit given in parenthesis. Some of the lines showed a resolved splitting due to the spin rotation interaction. This was averaged for fitting purposes. The average equilibrium internuclear distance derived from the upsilon = 0 and 1 rotational constants of the four isotopomers is 1.171800(6) A which is in good agreement with the value determined from microwave spectroscopy.

Absorption↗

Transient edema of the spinal cord as a result of spontaneous acute epidural hematoma in the thoracic spine.

We present an unusual case of spontaneous epidural hemorrhage in the thoracic spine resulting in rapid onset of transient and extensive edema in the spinal cord. The patient presented with acute onset of midscapular back pain, bilateral lower extremity weakness, and bladder dysfunction. Repeat MRI 20 days after decompression of the hematoma showed residual hematoma and complete resolution of the spinal cord edema. The implications and differential diagnosis of spinal cord edema in this clinical setting are discussed.

Acute Disease↗

Normal age-related signal change in the laryngeal cartilages.

MRI may be used for detecting cartilage invasion in patients with laryngeal carcinoma. However, the normal laryngeal ossification pattern has not been studied. Our purpose was to examine the normal age-related signal patterns in the cricoid, thyroid and arytenoid cartilages on T1-weighted images. Signal in the cartilages was assessed by two radiologists in a blinded fashion using three-point scales for intensity and symmetry. Statistical analysis consisted of logistic and monotonic regression. There was excellent interobserver agreement (>85%) for all categories. The cartilages predominantly ossify symmetrically and the extent of high signal from all three increases with age. The latter may help in detection of cartilage invasion by tumor in older patients. Normal symmetry may be helpful when comparing sides for tumor invasion.

Adolescent↗

Follow-up study of renal transplant recipients treated at the Guatemalan Social Security Hospital.

Guatemala is Central America's westernmost country, with a ratio of 500,000 inhabitants per nephrologist. Yearly reports show an average of 150 new end-stage renal disease patients and 40 renal transplants, which are performed at two public health care facilities. The aim of this study was to describe the results of the transplant program at one of these centers (Social Security Hospital of Guatemala). Our program began in 1986, performing an average of 17 transplants per year. Cyclosporine has been used since 1992, and since 2001, C2 has been routinely monitored. Data on 255 patients (of 293) were available for analysis. Male-to-female ratio was 7:1, with 94% having received hemodialysis as their replacement therapy. The mean age at transplant was 35 years and living related donors used in 95%. The average duration of follow-up was 7 years. The mean creatinine and C2 level at most recent visit were 1.36 mg/dL and 864 ng/mL, respectively. A significant reduction in the incidence of acute rejection episodes was seen after the initiation of C2 monitoring (3% vs 1.2%). In general, these results are similar to data in other countries. The number of transplants performed must be increased to meet the current demand, and the cadaveric source of donation is the obvious way to do so. C2 monitoring is an example of technical improvements directed to optimize available resources.

Azathioprine↗

Adenosquamous carcinoma of the head and neck: criteria for diagnosis in a study of 12 cases.

AIMS: Adenosquamous carcinoma (ASC) of the head and neck is an unusual neoplasm in which a general consensus with regard to diagnostic criteria has not yet been reached. In this study we report the clinicopathological results of 12 ASCs, with special attention to their histological and immunohistochemical characteristics in order to define this neoplasm more precisely. METHODS AND RESULTS: All the patients were male with a peak incidence in the sixth decade of life. The tumours were located most frequently in the larynx and oral cavity, followed by the nasal cavity and pharynx. ASCs had two distinct histological components. The most extensive one was an usual keratinizing squamous cell carcinoma, arising from the surface epithelium, where characteristically severe dysplasia or carcinoma in situ was found in all cases. The second component was an adenocarcinoma, usually displayed in the deepest areas of the tumour. Evidence of origin from salivary or seromucinous glands was not found. Immunohistochemical studies demonstrated in most cases positivity of glandular differentiated areas for carcinoembryonic antigen (CEA) (11/12), CK7 (9/12) and CAM5.2 (7/12), whereas the squamous cell component was unreactive or reacted only focally for these markers. High-molecular-weight cytokeratin 34BE12 was positive in both components and CK20 was always negative. All cases showed high expression of Ki67 antigen. Most of them had overexpression of p53 (8/12) and DNA aneuploidy (10/12). Fifty percent of patients with ASC died of disease after a mean period of 23 months (range 12-35 months). CONCLUSIONS: ASC of the head and neck is an aggressive neoplasm that originates in the surface epithelium of the upper respiratory tract. Severe dysplasia or carcinoma in situ is usually found and its recognition helps to make the diagnosis. In addition to mucin stains, positive immunoreactivity for CEA, CK7 and CAM5.2 helps to identify the glandular component.

Adult↗

A longitudinal neuropsychological study of partial brain radiation in adults with brain tumors.

OBJECTIVE: To investigate longitudinal cognitive functioning in patients with brain tumor treated with modern highly conformal fractionated partial brain radiation therapy (RT). METHODS: Seventeen (of 22 initial consecutive patients) adults with primarily low-grade brain neoplasms who underwent either biopsy or tumor resection were tested at pre-RT baseline and at 3, 6, 12, and 24 months after baseline. Participants were classified as RT-treated nonprogressors (n = 12) or progressors (n = 3) based on serial follow-up structural imaging. Two patients received surgery only and served as controls to help minimize surgical, practice, test form, or other potential non-RT effects. Serial neuropsychological assessments were conducted using alternate forms of the Selective Reminding Test, 10/36 Spatial Recall Test, and Symbol Digit Modality Test (oral, written) as well as the Shipley Scale (baseline only), Wechsler Adult Intelligence Scale-Revised Digit Span, Trail Making Test, and the Symptom Checklist-90-Revised Global Severity Index scale. RESULTS: There was evidence of subtle attention and memory improvement in RT-treated nonprogressors throughout the 2-year period, with no evidence of cognitive decline. In contrast, patients with disease progression evidenced more substantial decline in memory and attention. CONCLUSIONS: Partial brain fractionated RT was not associated with adverse neuropsychological effects through the first 2 years following therapy.

Adult↗

Proton magnetic resonance spectroscopy of brain-stem lesions.

The imaging findings of brain-stem lesions are often nonspecific and histological diagnosis is limited because of fear of complications associated with biopsy. A noninvasive method for tissue characterization is therefore highly desirable. We undertook a review of proton magnetic resonance spectroscopy (MRS) of patients with solitary brain-stem lesions to determine if MRS could characterize them. We carried out single- or multivoxel proton MRS using long echo times (135 or 270 ms) on 34 patients with solitary brain-stem lesions. We analyzed the following peaks: choline (Cho), creatine (Cr), N-acetylaspartate (NAA), and lipids/lactate (Lip) and calculated peak height ratios for Cho/Cr, NAA/Cr and Lip/Cr. The results were compared with histology in nine patients and with the presumptive diagnosis in 25. We also performed single-voxel proton MRS on the brain stem of five normal volunteers. There were differences in all ratios between controls and the patients with neoplastic and non-neoplastic lesions: Cho/Cr was low in non-neoplastic and high in neoplastic lesions (control: 1.8+/-0.1; non-neoplastic: 1.4+/-0.2; neoplastic: 2.0+/-0.2); NAA/Cr was low in non-neoplastic, and lower in neoplastic lesions (control: 2.3+/-0.1; non-neoplastic: 1.4+/-0.2; neoplastic: 1.2+/-0.1), and Lip/Cr was elevated in both neoplastic and non-neoplastic lesions (control: 0.04+/-0.02; nonneoplastic: 1.9+/-0.7; neoplastic:1.9+/-0.7).

Aspartic Acid↗

Lead intoxication in gestational and lactation periods alters the development of male reproductive organs.

The effect of lead (Pb) intoxication during pregnancy and lactation on the male reproductive system was studied to evaluate the alterations caused by Pb in the development of pups. The investigations covered the effect of lead on the course of spermatogenesis and the development of the epididymis and reproductive glands. For this purpose, dams were intoxicated with 300 mg/L Pb during the gestational period and through lactation. Pups were sacrificed on Postnatal (PN) Days 12 and 21. Blood lead (PbB) and plasma iron concentrations were measured, and blood cells counted. Biochemical studies as well as histochemical analyses were performed on testes and accessory glands of the reproductive system. Lead intoxication resulted in a decrease in testis and seminal vesicle weights and an increase in DNA and RNA levels on PN Day 21. Total protein was significantly decreased by the toxicant, and alkaline and acid phosphatase levels of the gonads were reduced. Effects were also reflected in the reduction of the thickness of epithelium and of seminiferous tubule diameter (STD) as a consequence of the action of lead in the reduction in numbers of prospermatogonia and spermatocytes. Results indicate that the reproductive system targets of lead intoxication are not only the testes; lead intoxication results in the inhibition of testicular, epididymal, and seminal vesicle function, altering the biochemical composition of these organs, and consequently, affecting the normal development of germinal cells.

Animals↗

Effects of dietary fish oil on the fatty acid composition of the main lipid classes of chick plasma lipoproteins.

We have studied the effects of diet supplementation with 10% fish oil on fatty acid composition of the main lipid classes of chick plasma lipoproteins bearing in mind the relationship between platelet aggregation and eicosanoid production from arachidonic acid. Fish oil drastically increased the percentages of 20:5 n-3 and 22:6 n-3 acids in the high density lipoprotein lipids. The 20:5/22:6 ratio increased in triacylglycerol fraction whereas in phospholipids and cholesterol esters both 20:5 and 22:6 acids increased in a similar proportion. The percentage of arachidonic acid was higher in phospholipids than in the other lipid classes from this lipoprotein fraction and was significantly reduced by fish oil feeding. Linoleic acid, which was the most abundant fatty acid in cholesterol esters, strongly decreased after fish oil consumption. Changes induced in low- and very low density lipoproteins were similar to that observed in the high density lipoproteins. However, in the very low density lipoproteins, the 20:5/22:6 ratio was not increased in triacylglycerols, in contrast to that found in the high- and low density fractions. Our results suggest that decreases observed by fish oil feeding in the percentages of arachidonic acid in phospholipids and linoleic acid in cholesterol esters in the three lipoprotein fractions may be of importance to explain some pharmacological effects of n-3 PUFA with regard to vascular diseases.

Animals↗

HPV types and cofactors causing cervical cancer in Peru.

We conducted a hospital-based case-control study in Peru of 198 women with histologically confirmed cervical cancer (173 squamous cell carcinomas and 25 cases of adenocarcinoma/adenosquamous carcinoma) and 196 control women. Information on risk factors was obtained by personal interview. Using PCR-based assays on exfoliated cervical cells and biopsy specimens, HPV DNA was detected in 95.3% of women with squamous cell carcinoma and in 92.0% of women with adenocarcinoma/adenosquamous carcinoma compared with 17.7% in control women. The age-adjusted odds ratio was 116.0 (95% Cl = 48.6-276.0) for squamous cell carcinoma and 51.4 (95% Cl = 11.4-232.0) for adenocarcinoma/adenosquamous carcinoma. The commonest types in women with cervical cancer were HPV 16, 18, 31, 52 and 35. The association with the various HPV types was equally strong for the two most common types (HPV 16 and 18) as for the other less common types. In addition to HPV, long-term use of oral contraceptives and smoking were associated with an increased risk. HPV is the main cause of both squamous cell carcinoma and adenocarcinoma in Peruvian women.

Adenocarcinoma↗