Biomedical subjects

A Linares

Publications and source records attributed to A Linares.

At least 55 records · Page 3Linked to original sources

PubMed1993

Response related factors in recombinant interferon alfa-2b treatment of chronic hepatitis C.

In an analysis of the clinical and laboratory variables that can influence the response to interferon alfa-2b treatment, 48 patients with chronic hepatitis C virus infection received interferon 5 million units (MU) subcutaneously three times weekly for eight weeks followed by 3 MU three times weekly for seven months. Response related factors on univariate analysis were found to be age > 40 years, non-parenteral source of infection, pretreatment positive antinuclear antibodies (ANA), cirrhosis, and high serum iron, ferritin, gamma glutamyl transferase, and IgM. An independent predictive value (multivariate analysis) was also found for cirrhosis, ANA, serum iron, and ferritin. A baseline aspartate aminotransferase/alanine aminotransferase ratio of 0.5 and a striking increase during interferon treatment were associated with a complete response.

Adolescent↗

PubMed1993

A comparative study of the in vitro and in vivo formation of lanosterol derivatives from acetate by different chick tissues.

The optimal conditions for the synthesis of lanosterol derivatives, previously demonstrated as inhibitors of cholesterogenesis, have been studied in 14-day-old chicks using acetate as precursor. In experiments carried out in vitro, the relative percentage of lanosterol derivatives in the total nonsaponifiable fraction was practically similar in each tissue at any incubation time considered (15-120 min). This percentage was higher in kidney and duodenal mucosa than in liver. The percentage of lanosterol derivatives was constant at any acetate concentration assayed (1-12 mM) in liver and duodenal mucosa, while in kidney this percentage increased at high acetate concentration (8-12 mM). In experiments carried out in vivo, the relative percentage of lanosterol derivatives was lower than that found in each tissue in the in vitro conditions. This behaviour was opposed to the acetate incorporation into cholesterol in the same experimental conditions. No significant differences were observed in the in vivo acetate incorporation into lanosterol derivatives by chick brain at different times of day. However, in duodenal mucosa and kidney maximal values were found during the dark period, on the contrary to that previously observed in the percentage of cholesterol. Our results demonstrated that kidney and duodenal mucosa were the chick tissues in which the higher percentage of lanosterol derivatives was accumulated.

Acetates↗

PubMed1992

Perinatal outcome of very low birthweight infants by mode of delivery.

In order to evaluate the influence of mode of delivery on perinatal morbidity and mortality in vertex infants weighing less than 1500 g (VLBW), we made a retrospective study of 152 singleton newborns, in vertex presentation, with a birthweight of less than 1500 g, delivered in the Cruces Hospital (Vizcaya, Spain), a major perinatal referral center, between 1 January 1987 and 31 December 1989. Twins and infants with lethal congenital anomalies or gross intrauterine growth deviations were excluded from the study (n = 71). Of the infants studied (n = 81), 37 were delivered by cesarean section (mean weight 1120 +/- 206 g, range: 680-1495 g) and 44 were delivered vaginally (mean weight 1029 +/- 283 g, range: 530-1475 g). The patients were divided into four groups: Group A: 500-749 g (n = 10); Group B: 750-999 g (n = 21); Group C: 1000-1249 g (n = 27); and Group D: 1250-1499 g (n = 23). The percentages of cesarean sections in each group were 10%, 42%, 66% and 39%, respectively. A comparison within each group of immediate perinatal outcome (Apgar score and umbilical vein cord pH), as well as mortality and sequelae up to 1 year of age did not yield any significant differences between cesarean and vaginal birth. We conclude that cesarean delivery does not appear to offer improved outcome over vaginal delivery in live births without congenital anomalies. For this reason, we believe that fetal weight should not be the only obstetrical variable considered when deciding whether or not to perform a cesarean section in these circumstances.

Adult↗

PubMed1992

[Ulcerative colitis and amyloidosis. Presentation of a case and review of the literature].

A case of ulcerative colitis associated with secondary amyloidosis in a 62-year-old man who died from septic shock and pneumonia complicating head injury is reported. Amyloid deposition was incidentally found at autopsy. Proteinuria and hepatomegaly discovered a few days before his death were the only signs of amyloidosis. The postmortem examination showed chronic ulcerative colitis (remitting form) with pseudo-polyps and amyloid deposition in the liver, spleen, pancreas, rectum, adrenals and kidneys. Although secondary amyloidosis complicating with Crohn's disease has been frequently reported, amyloidosis associated with ulcerative colitis has been exceptionally described and only 10 cases have been collected from the literature.

Amyloidosis↗

PubMed1992

Comparative effect of fasting on acetoacetate and D-3-hydroxybutyrate metabolism in the newborn chick.

The effect of 24 h fasting on ketone body utilization by three extranervous tissues, liver, duodenum and kidney, was studied in two critical ages of neonatal chick: 4 and 9 days. In 4-day-old chick, plasma concentration of 3-hydroxybutyrate increased about 9-fold after 24 h starvation, while in 9-day-old chick this parameter increased about 23-fold in the same conditions. Hepatic lipogenesis from both precursors sharply decreased by fasting. Changes in the lipogenic activity of duodenum were less patent. However, we have found a clear increase in lipogenesis in chick kidney after 24 h starvation. CO2 production from acetoacetate was higher than that found from hydroxybutyrate. No significant differences in the acetoacetate oxidation to CO2 was observed in any tissue assayed after 24 h fasting. 14C incorporation from ketone bodies into amino acids was clearly decreased in kidney from 9-day-old chick by fasting. In liver and duodenum, acetoacetate incorporation into amino acids was higher than that from hydroxybutyrate.

3-Hydroxybutyric Acid↗

PubMed1991

Influence of fibric acid derivatives on intermediate filament proteins in myocardiocyte cultures.

We analyzed desmin and vimentin accumulation in chick myocardiocyte cultures treated with the fibric acid derivatives bezafibrate, fenofibrate and gemfibrozil. The most noteworthy finding was the 50% decrease in the cytoplasmic desmin fraction in cells treated with gemfibrozil in comparison to control cultures, and the 19% increase in the cytoskeletal fraction in cultures treated with gemfibrozil and with bezafibrate. Vimentin accumulation by cells treated with bezafibrate was similar to that in control cultures, however the cytoskeletal vimentin fraction rose by 26% after treatment with gemfibrozil, and fell 13% after treatment with fenofibrate. No vimentin was found in the cytoplasmic fraction of cell treated with bezafibrate. Given the role of intermediate filaments in heart muscle contraction, fibric acid derivative- induced changes in the cytoplasmic and cytoskeletal concentrations of intermediate filament proteins may be related with the secondary effects of these drugs on heart rate.

Animals↗

PubMed1991

[Crohn's disease and amyloidosis. An association to be considered].

Two instances of Crohn's disease and amyloidosis are presented. The time elapsed between the diagnosis of Crohn's disease and that of amyloidosis was 2 and 8 years respectively. The first case had hepatosplenomegaly and moderate proteinuria; the other one, severe proteinuria in the nephrotic syndrome range. One patient had ileocolic disease and the other disease limited to the terminal ileum. In both cases renal functional was normal. The diagnosis was made by liver biopsy in one patient and by repeated renal biopsy in the one with nephrotic syndrome. Ileocolic resection was undertaken in one patient without complications. Screening for amyloidosis is important in patients with Crohn's disease.

Adult↗

PubMed1990

In vivo utilization of D(-)-3-hydroxybutyrate by chick brain and spinal cord.

The in vivo utilization of D-3-hydroxy[3-14C]butyrate for oxidation in the whole animal and for lipid and amino acid synthesis in brain and spinal cord of overnight-fasted 15-day-old chicks has been measured. Appreciable amounts of injected 3-hydroxy[3-14C]butyrate were expired as 14CO2 one hour after injection, the total amount of which increased with increasing dosages. Lipid synthesis was high in both brain and spinal cord. Free cholesterol and phospholipids were the main lipids labeled in both tissues, increasing with time after injection up to 120 min. The incorporation of radioactivity into triglycerides, esterified cholesterol and free fatty acids was not time-dependent. Increased concentrations of 3-hydroxybutyrate gave rise to higher synthetic rates both in brain and spinal cord. The rate of amino acid synthesis was slightly higher in brain than in spinal cord. Glutamate was always the major amino acid formed.

3-Hydroxybutyric Acid↗

PubMed1990

In vivo lipid and amino acid synthesis from 3-hydroxybutyrate in 15-day-old chick.

The in vivo utilization of 3-hydroxybutyrate for lipid and amino acid synthesis in liver, kidney and duodenal mucosa of overnight-starved 15-day-old chicks has been investigated. Lipid synthesis was higher in liver and duodenal mucosa than in kidney. Triglycerides were the main lipids synthesized from 3-hydroxybutyrate in liver and kidney, while in duodenal mucosa a higher amount of phospholipids was observed. This tissue utilized a high percentage of 3-hydroxybutyrate for the synthesis of free cholesterol, in agreement with the major role of intestine in body cholesterogenesis. All of the assayed tissues synthesized amino acids from 3-hydroxybutyrate at a similar rate, glutamate being always the main amino acid formed.

3-Hydroxybutyric Acid↗

PubMed1989

Ketone body utilization in duodenum. Differential effect of fasting on lipogenesis from acetoacetate and 3-hydroxybutyrate.

The effect of fasting and refeeding on oxidation, lipogenesis and amino acid synthesis from ketone bodies has been studied in neonatal chick duodenal mucosa. Oxidation and amino acid synthesis were higher from acetoacetate and were stimulated by fasting from both 3-hydroxybutyrate and acetoacetate. On the contrary, lipogenesis was always higher from 3-hydroxybutyrate and fasting reduced lipogenesis rate from acetoacetate (by 66%) but not from 3-hydroxybutyrate. Results suggests the existence of a cytosolic fast-dependent acetoacetyl-CoA synthetase in chick duodenal mucosa which is involved in phospholipid synthesis.

3-Hydroxybutyric Acid↗

PubMed1988

In vivo utilization of [3-14C]acetoacetate for lipid and amino acid synthesis in the 15-day-old chick.

1. The utilization of different concentrations of acetoacetate for the in vivo synthesis of lipids and amino acids has been studied in brain, spinal cord, liver, small intestine and kidney of 15-day-old chicks. Both lipid and amino acid synthesis increased in an almost linear fashion with precursor concentration in the five tissues mentioned. 2. Lipid synthesis was very high in spinal cord, followed in decreasing order by brain, small intestine, liver and kidney. At the highest concentration assayed (48 mM) the main lipids synthesized were triglycerides in liver (75%) and kidney (52%) and cholesterol in brain (47%), spinal cord (47%) and small intestine (42%). 3. Amino acid synthesis from acetoacetate did not vary markedly among the five organs, although brain and spinal cord showed higher rates at the maximal concentrations of precursor. Glutamate was always the main amino acid formed.

Acetoacetates↗

PubMed1988

Age-related changes in the mevalonate metabolism in vivo in chick kidneys.

The mevalonate incorporation in vivo into total nonsaponifiable lipids by chick kidneys drastically increased after hatching, reaching similar levels to those previously observed in liver. Cholesterol was the major sterol formed from mevalonate from 11 days onward, while a fraction of polar nonsaponifiable lipid(s) was observed as the major compound(s) synthesized at 5-8 days. Relative percentages of squalene, squalene oxide(s) and lanosterol synthesized from mevalonate also increased between 11-18 days after hatching. Results in this paper demonstrate for the first time the accumulation of a fraction of nonsaponifiable lipid(s) identified as lanosterol derivatives and cholesterol precursors formed by kidneys from [5-14C]mevalonate in experiments carried out in vivo, as well as their evolution during postnatal period.

Aging↗

PubMed1987

Posthatching evolution of in vivo mevalonate metabolism in chick liver.

The in vivo mevalonate incorporation into total nonsaponifiable lipids by chick liver was minimal after hatching and drastically increased between 1-5 days. The hepatic synthesis of different cholesterol precursors emerged sequentially after hatching. Between 1-5 days increased strongly the conversion of mevalonate into squalene and also the formation of oxygenated lanosterol derivatives from squalene. The conversion of squalene became completely active at day 8. Cholesterol formation from lanosterol derivatives was completely activated between 8-11 days. Results in this paper demonstrate for the first time the accumulation of a fraction of nonsaponifiable lipids identified as lanosterol derivatives and cholesterol precursors formed from [5-14C]mevalonate in experiments carried out in vivo. Postnatal evolution of these oxysterols may explain the great increase of 3-hydroxy-3-methylglutaryl-CoA reductase activity found in chick liver between 5-11 days, simultaneous or posterior to the diminution of the oxygenated cholesterol precursors.

Age Factors↗

PubMed1986

[Regional organization of a neonatal transportation system].

Organization, operational plans, and initial experience of a Regional Neonatal Transport System is described. The system covers provinces of Bizcaia, and Alava in Northern Spain, with a total of 17,500 annual deliveries. In the first 10 months 31 newborn infants were transported. Their mean birth weight was 2,066 +/- +/- 931 Gm. Ten infants had a birth weight less than 1,500 Gm, and in 22 (71%) of them gestational age was under 37 weeks. Some types of respiratory distress was present in 71% of them, and 25.8% required mechanical ventilation during transport. Hypothermia was present in 36% of the infants at referral center, percentage that decreased to only 9% at their arrival to the NICU. During transport mean body temperature increased from 35.33 +/- 1.07 degrees to 35.84 +/- 0.9 degrees C (p less than 0.01). Infants condition was judged to improve in 13% of them. Overall survival rate was 74.2%, being 80.9% in those weighting from 1,000 to 1,500 Gm. Infants who were hypothermic had a lower survival (45.5%) than those who were not (90%) (p less than 0.05).

Birth Weight↗

PubMed1985

Studies on the diurnal rhythm of mevalonate metabolism by sterol and nonsterol pathways and of mevalonate-activating enzymes.

Both in vivo and in vitro incorporation of mevalonic acid into nonsaponifiable lipids by 17-day-old chick liver and kidney did not show diurnal rhythm. Using 14CO2 production from MVA as an index of the shunt pathway not leading to sterols, we have demonstrated for the first time that there is no diurnal rhythm in this pathway. No significant differences were found in the specific activities of mevalonate kinase, mevalonate-5-phosphate kinase and mevalonate-5-pyrophosphate decarboxylase from chick liver and kidney throughout a period of 24 hr, using [1-14C]mevalonate as substrate. The absence of diurnal rhythm in the decarboxylase activity was corroborated by further experiments carried out using [2-14C]mevalonate-5-pyrophosphate as specific substrate of this enzyme.

Animals↗

PubMed1984

Effect of dietary cholesterol on mevalonate metabolism by sterol and nonsterol pathways.

Results in the present communication demonstrate for the first time that the shunt pathway of mevalonate not leading to sterols is regulated by cholesterol feeding in a reverse fashion to the sterol pathway. Mevalonate incorporation into nonsaponifiable lipids by liver slices was inhibited by cholesterol feeding while the shunt pathway was clearly enhanced. Moreover, inhibition of renal sterologenesis by dietary cholesterol is also reported. These changes in the mevalonate metabolism are closely correlated with the increase observed in the esterified cholesterol content in neonatal chick liver and kidneys after 10 days of 2% cholesterol supplementation of the diet.

Animals↗

PubMed1984

The in vivo incorporation of acetate into different non-saponifiable lipids by neonatal chick tissues.

The in vivo incorporation of [l-14C]acetate into non-saponifiable lipids was higher in neonatal chick liver than in intestinal mucosa, brain and kidneys, and proportional to the amount of substrate injected (2-20 mumole). 14CO2 expired in the breath was also proportional to the dose of acetate. Radioactivity from [l-14C]acetate accumulated by liver was maximal 30 min after the injection of acetate and decreased afterwards. Acetate was mainly incorporated into cholesterol by all the tissues assayed, although small percentages of lanosterol and squalene were obtained in liver. In this tissue, distribution of radioactivity was practically independent from the dose of substrate injected while in intestinal mucosa, brain and kidneys the percentage of cholesterol increased with this dose. The time course of the in vivo formation of different non-saponifiable lipids by neonatal chick tissues was also studied. More than 90% of radioactivity in this fraction obtained 15 min after the acetate injection was recovered as cholesterol in liver and kidneys, while in brain and intestinal mucosa this percentage was about 50% at this time, increasing afterwards. A high percentage of lanosterol was found in brain and intestinal mucosa 15 min after the injection of acetate.

Acetates↗

PubMed1984

Postnatal development of the sterol and nonsterol mevalonate metabolism in chick liver and kidneys. Effect of cholesterol feeding.

The effect of 2% cholesterol feeding on changes throughout postnatal development of total, free, and esterified cholesterol in neonatal chick liver and kidneys was studied. The increase observed in the hepatic cholesterol content after supplementation of the diet with 2% cholesterol was mainly due to the accumulation of esterified cholesterol. Small but significant differences were also found in the esterified cholesterol content in kidneys between control and cholesterol-fed animals. In normally fed chicks, the hepatic percentage of squalene synthesized from mevalonate decreased during the first days of independent life while cholesterol percentage increased. On the contrary, the percentage of squalene recovered in kidneys immediately after hatching was minimal, increasing during postnatal development. Addition of 2% cholesterol to the diet produced a clear inhibition in the mevalonate incorporation into nonsaponifiable lipids by liver slices, especially from 4 days onwards. This inhibition was particularly clear in the percentage of cholesterol synthesized. Mevalonate incorporation by kidney slices was higher than in liver, although cholesterol supplementation had little influence on the percentage of each nonsaponifiable lipid formed. In normally fed chicks, kidneys metabolized mevalonate by the shunt pathway not leading to sterols at a rate more than 50 times that of liver. Cholesterol feeding produced a clear enhancement of the hepatic shunt pathway while in kidneys it had practically no effect.

Aging↗