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Biomedical subjects

J Planas

Publications and source records attributed to J Planas.

At least 37 records · Page 2Linked to original sources
PubMed1992

Glucose metabolism by trout (Salmo trutta) red blood cells.

Glucose metabolism has been studied in Salmo trutta red blood cells. From non-metabolizable analogue (3-O-methyl glucose and L-glucose) uptake experiments it is concluded that there is no counterpart to the membrane transport system for glucose found in mammalian red blood cells. Once within the cells, glucose is directed to CO2 and lactate formation through both the Embden-Meyerhoff and hexose monophosphate shunts; lactate appears as the most important end-product of glucose metabolism in these cells. From experiments under anaerobic conditions, and in the presence of an inhibitor of pyruvate transfer to mitochondria, most of the CO2 formed appears to derive from the hexose monophosphate pathway. Appreciable O2 consumption has been detected, but there is no clear relationship between this and substrate metabolism. Key enzymes of glucose metabolism, hexokinase, fructose-6-phosphate kinase and, probably, pyruvate kinase are out of equilibrium, confirming their regulatory activity in Salmo trutta red blood cells. The presence of isoproterenol, a catecholamine analogue, induces important changes in glucose metabolism under both aerobic and anaerobic conditions, and increases the production of both CO2 and lactate. From the data presented, glucose appears to be the major fuel for Salmo trutta red blood cells, showing a slightly different pattern of glucose metabolism from rainbow trout red blood cells.

3-O-Methylglucose↗
PubMed1992

Twenty years of experience with particulate silicone in plastic surgery.

The use of particulate silicone in plastic surgery involves the introduction of solid silicone into the body. The silicone is in small pieces in order for it to adapt to the shape of the defect. This way large quantities can be introduced through small incisions. It is also possible to distribute the silicone particles from outside the skin to make the corrections more regular. This method has been very useful for correcting post-traumatic depressions in the face and all areas where the depression has a rigid back support. We consider it the treatment of choice for correcting the funnel chest deformity.

Face↗
PubMed1992

Changes in plasma glucagon, insulin and tissue metabolites associated with prolonged fasting in brown trout (Salmo trutta fario) during two different seasons of the year.

1. Pyrenean brown trout juveniles (Salmo trutta fario) were fasted for 50 days in late winter (experiment 1) and summer (experiment 2). Plasma insulin, glucagon and glucose and some metabolites in plasma and in tissues were analysed. 2. Glucagon increased significantly on the 3rd day of fasting in the winter experiment (controls 653.7 +/- 92.4 pg/ml, fasted 912.7 +/- 135.2 pg/ml), and the same tendency was observed on the 5th day in the summer experiment (controls 430.5 +/- 56.2 pg/ml, fasted 555.5 +/- 95.3 pg/ml). During this initial period of fasting, plasma glucose was maintained in both experiments (75.5 +/- 4.7-67.6 +/- 4.1 mg/100 ml), but from day 8, glucose and glucagon decreased simultaneously. 3. Insulin decreased from the beginning of fasting, reaching lowest values after 50 days of fasting (winter experiment: controls 6.4 +/- 0.3 ng/ml, fasted 1.6 +/- 0.1 ng/ml; summer experiment: controls 4.8 +/- 0.1 ng/ml, fasted 1.2 +/- 0.2 ng/ml). Glucagon/insulin molar ratio (G/I) increased after 3 days in the winter experiment (controls 0.21 +/- 0.02, fasted 0.39 +/- 0.05), while in the summer experiment, the ratio rose from day 5 and reached a peak at day 30 (controls 0.16 +/- 0.02, fasted 0.48 +/- 0.07). 4. Muscle proteins were significantly mobilized after 50 days of fasting. Visceral index decreased significantly after day 15 while liver glycogen was already significantly lower at day 8. However, in the summer experiment, a transitory increase of liver glycogen was observed at day 30, coinciding with the peak of G/I.

Animals↗
PubMed1991

Full length mouse glycophorin gene constructed using recombinant polymerase chain reaction.

Recently, an incomplete cDNA clone for a major mouse glycophorin gene, pGP315, and a genomic clone, pGX7 (which contains the first exon and nucleotide sequences around the transcription start sites) was isolated and sequenced by Matsui et al. (1). Since there were no available restriction sites for the construction of a full length mouse glycophorin A gene, the recombinant PCR technique was adapted to splice together the above two partial sequence clone inserts to obtain a full length recombinant DNA fragment (1053 bp) containing the proper sequence of mouse glycophorin A cDNA. The PCR reconstructed DNA fragments were verified by: gel electrophoresis to contain the expected sizes, hybridization to probes made from the DNA components before recombination, and confirmed by the restoration of a previously destroyed restriction enzyme site. The corrected gene sequence for pGP315 is also reported.

Animals↗
PubMed1991

Isolation and primary structure of glucagon from the endocrine pancreas of Thunnus obesus.

Glucagon has been isolated from the endocrine pancreas of a tunid, Thunnus obesus. The primary structure of the glucagon molecule was established as H S E G T F S N D Y S K Y L E T R R A Q D F V Q W L K N S. The sequence is identical to those of sculpin and flounder glucagon and glucagon II from anglerfish. It also shows high homology to the mammalian hormone (76%). The mass determined by fast-atom bombardment (3508) was consistent with the proposed structure. Immunological properties of the tuna glucagon were analyzed by radioimmunoassay, showing a high degree of cross-reactivity with the 30K antibody.

Amino Acid Sequence↗
PubMed1991

Some plasma hormones and metabolites in the Pyrenean brown trout (Salmo trutta fario).

1. Pyrenean brown trout (Salmo trutta fario) from 200 to 1700 g were analysed in lots of 12 specimens in March, April, July and October 1988, and in January 1989. 2. Hormones (insulin, glucagon, cortisol) and metabolites (glucose, lactate, proteins, triglycerides) were determined in plasma. 3. Body parameters (length and weight) increased progressively, while plasma metabolites and hormones were more dependent on seasonal and sexual conditions. 4. Plasma insulin presented a maximum in spring (11 ng/ml) and a minimum in January (5 ng/ml). A clear relationship between insulin and annual growth rates was established. Plasma glucagon showed annual values between 700 and 1500 pg/ml, with significant seasonal variations. The molar ratio glucagon/insulin oscillated from 0.21 in January to 0.38 in July. 5. Plasma glucose variations agreed with those of pancreatic hormones, especially evident with glucagon levels. Proteins were more uniform throughout year, and plasma lipids were especially associated to the reproductive state in females.

Animals↗
PubMed1991

Influence of "diagnostic delay" upon cancer survival: an analysis of five tumour sites.

STUDY OBJECTIVE: The aim was to assess the relationship between survival, tumour stage, and the interval from first symptom to diagnosis (SDI, or duration of symptoms). DESIGN: This was a retrospective follow up study of a cohort of patients registered in the tumour registry of the Hospital del Mar (Barcelona). SETTING: Hospital based tumour registry, with patients derived mainly from the City of Barcelona. PARTICIPANTS: 1247 cases of lung, breast, stomach, colon, or rectal cancer were analysed using survival curves and Cox proportional hazards regression. Subjects (mean age 63.6 years) were followed for a median length of 12.9 months after diagnosis. At the time of diagnosis one fourth of patients had disseminated disease. MEASUREMENTS AND MAIN RESULTS: Based on clinical records, a physician registered the onset time of the first symptom attributable to cancer (from which the SDI is computed), as well as the tumour stage at diagnosis. Other measurements followed standard tumour registry procedures. Overall, the crude mean SDI was 5.15 months (SD 8.03, median 2.03); only 24.5% of cases had an SDI less than a month. Crude mean SDIs by anatomical site were as follows: lung cancer 3.07 months; breast 7.44; stomach 5.34; colon 5.74; rectum 5.03. Tumour extension did not appear to be significantly influenced by SDI, only breast cancer showing a distinct pattern of increased extension with increasing SDI. As expected, the probability of survival decreased monotonically with increasing stage in all sites. Tumour site was also a significant predictor of survival, which at one year ranged from 93% for breast cancer to 28% for lung cancer. However, a longer SDI tended sometimes to be associated with a better chance of survival, a fact that was most apparent in colon cancer. All Cox proportional hazards models showed a consistent picture: SDI was not a significant predictor of survival (age and sex adjusted hazard ratios ranging from 0.97 to 1.01), neither was sex; age did predict survival, and so did site and stage. CONCLUSIONS: The results provide further evidence of a very weak relationship between SDI and tumour stage at diagnosis (except for breast cancer), and between SDI and survival, thus emphasising some limitations within which early clinical detection operates. They also suggest that in addition to reflecting patient and physician behaviour, as well as the functioning of the health system, SDI may be influenced by the biological behaviour of the tumour.

Adult↗
PubMed1991

Cadmium induction of metallothioneins in several dogfish organs.

Dogfish Scyliorhinus canicula were exposed to 50 mg/l Cd for 4 days for inducing metallothionein synthesis. Spleen, pancreas, kidney and gonads were dissected out and metallothionein presence was checked by means of gel filtration chromatography in Sephadex G-75 and sodium dodecyl sulphate polyacrylamide electrophoresis. In pancreas and kidney, a cadmium-binding protein with spectroscopical and electrophoretic properties similar to those of dogfish liver metallothionein was found. In the other organs, the existence of an analogue protein but at very low concentrations is feasible.

Animals↗
PubMed1990

Organ iron content in New Hampshire chickens.

We have studied some hematological parameters and iron and ferritin iron contents in different organs of New Hampshire chickens at the ages of 4, 8, 13, and 18 wk for both sexes, as well as 24 wk for laying hens, in order to study the variations with age, the existence of sex differences, and the accommodations to laying. The hematocrit and hemoglobin levels did not show important variations, but plasma iron increased at laying. The iron and ferritin iron concentrations in liver and spleen increased more slowly during growth than the total iron and ferritin iron contents, and no significant decline was observed at laying. The iron concentration in the heart and pectoral muscle stayed constant throughout the period studied, and kidneys showed slight increase with age. However, the iron concentration in the intestine decreased from the proximal to the distal segments and also increased in the duodenum at laying. No differences caused by sex have been detected in the organs studied. The absence of differences caused by sex in the organ iron stores in favor of females, especially in liver, and the lack of influence of the laying process in iron stores could be a consequence of the low laying frequency of this strain.

Aging↗
PubMed1990

Effects of GnRH-associated peptide and its component peptides on prolactin secretion from the tilapia pituitary in vitro.

The rostral pars distalis (RPD), containing mainly prolactin (PRL)-secreting cells, of the pituitary from immature and mature tilapia was incubated for 16 hr at 27 degrees in hypoosmotic medium (300 mOsm/kg) in the presence (10(-8) and 10(-11) M) or absence of the human GnRH-associated peptide (GAP) molecule, a potent PRL-inhibiting factor in mammals (Nikolics et al., Nature (London) 316, 511, 1985), and of a series of its component peptides. The release of the two forms of PRL in tilapia into the medium was measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by densitometry. The variability inherent in this method was normalized by calculating PRL release as the percentage of the total hormone present in both tissue and medium. Newly synthesized PRL was detected by incorporation of [35S]methionine, introduced into the culture medium, by the PRL molecules. In immature tilapia, GAP inhibited the release of total PRL while stimulating the release of newly synthesized large PRL. Among the GAP fragments tested, 28-36 was the fragment that most significantly affected PRL secretion. Both concentrations of fragment 28-36 stimulated the release of newly synthesized PRL from immature rostral pars distalis (RPDs). This stimulation appears to be dependent on the osmotic pressure of the medium since this fragment did not affect PRL secretion in hyperosmotic medium (340 mOsm/kg). Fragment 38-49 inhibited total PRL release from mature RPDs. Fragment 51-66 stimulated the release of total PRL from mature RPDs. Examination of tissue and medium values in densitometric units after incubation with fragments 28-36 and 51-66 indicated that while the tissue content of PRL was decreased, the medium content of PRL was not affected. This suggests that fragments 28-36 and 51-66, in opposition to the situation found when the data are expressed as percentage release of PRL, may not stimulate PRL release but may instead decrease the tissue content of PRL. These results suggest that the entire human GAP molecule, as well as some of its fragments, may have direct effects on the PRL cells in the tilapia pituitary.

Animals↗
PubMed1990

Sexual and age variations of organ iron content in Shaver chickens.

1. Haematological values and iron content in liver, spleen, kidneys and intestine were determined in Shaver chickens of both sexes at 4, 8, 13 and 18 weeks and in females at 24 weeks (the beginning of the laying period). 2. The haematocrit decreased significantly in laying compared with non-laying females and the haemoglobin concentration was similar to that in the prelaying state. Plasma iron in laying females increased to four times the basal value at 13 weeks. 3. Females of 13 and 18 weeks (prelaying state) stored more iron than males at the same age. A simultaneous liver and spleen mobilisation of stored iron and increased intestinal iron accumulation took place in the laying process. The haematological variables examined were minimally altered. 4. The iron contents of both heart and kidneys were influenced by age and followed a linear trend, except that in the heart of females where a quadratic response was observed.

Age Factors↗
PubMed1989

Body and egg iron content in shaver and New Hampshire chickens.

1. A comparative study on the iron content in internal organs (blood, liver, spleen, kidneys and heart), carcass and feathers, as well as on the whole iron content has been carried out at different ages (4, 8, 13, 18 and 24 weeks), on two chicken breeds (shaver and New Hampshire). 2. The iron content in internal organs in shaver was higher than in New Hampshire. 3. A tendency of the iron content in the carcass to decrease with age has been observed for both breeds; values were higher for laying shaver hens. 4. The egg-producing strain, shaver, showed a greater iron status with a stable body iron content from 13 weeks on (53-55 ppm), permitting a constant laying frequency (90%) during an 18-month period, with only a small reduction of egg iron content from 33.8 to 31 ppm. 5. The whole body iron decreased progressively with age in the New Hampshire broiler strain to 42-49 ppm iron, and the laying process sharpened this tendency. A drastic reduction in laying, accompanied by a lower egg iron content (28.9 ppm iron), was observed. 6. Iron data obtained in the present paper reflect the specific genetic adaptation to egg production of the shaver strain.

Animal Husbandry↗
PubMed1989

Vitellogenin-iron and hemoglobin synthesis in avian reticulocytes.

Avian vitellogenin has been studied as an iron carrier for hemoglobin synthesis by reticulocytes. The Fe-vitellogenin uptake by the immature red cells is progressive with time, following an unspecific iron uptake process. The iron uptake from Fe-vitellogenin was in proportion to the immature red cells present and the radioactive iron was found in the hemoglobin synthesized by these cells. These results open up the possibility of assigning a secondary role to the Fe-vitellogenin in the avian erythropoiesis, added to the classical iron transport function for egg production.

Animals↗