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Biomedical subjects

A Latorre

Publications and source records attributed to A Latorre.

67 records · Page 4Linked to original sources
PubMed1988

Mitochondrial DNA evolution in the Drosophila obscura group.

We report a restriction-site study of the mitochondrial DNA (mtDNA) of seven species of the Drosophila obscura group. One species (D. azteca) belongs to the affinis subgroup; the other six species are classified in the obscura subgroup, three of them being from the old-world species (D. obscura, D. ambigua, and D. subobscura) and three from the new-world species (D. pseudoobscura, D. persimilis, and D. miranda). The mtDNA patterns suggest that the phylogeny of the group needs to be revised. The Nearctic obscura species appear as more closely related to D. azteca (affinis subgroup) than to the Palearctic species. The three Palearctic species are, in turn, a very heterogeneous group, with D. obscura no more closely related to D. subobscura and D. ambigua than to D. affinis or the Nearctic obscura species. The rates of mtDNA evolution are variable: some lineages have evolved at rates two or three times greater than others. If an average rate of 0.5% nucleotide substitutions/Myr is assumed, the divergence among the four main lineages in the phylogeny would have occurred 12-15 Myr ago, during the Miocene, which is consistent with biogeographic information.

Animals↗
PubMed1987

Patterns of puffing activity and chromosomal polymorphism in Drosophila subobscura. IV. Position effect at the boundaries of the E12 inversion.

The puffing patterns in polytene E chromosomes of Drosophila subobscura were followed in third-instar larvae and throughout the prepupa period. Two gene arrangements, Est and E1+2+9+12 were studied. A majority of puffs exhibit a similar pattern, but the puffs 61AC and 67AB behave differently in the two chromosomal arrangements, both in homozygotes and in heterozygotes. These two puffs are located at the end of the E12 inversion. This position effect is an interesting phenomenon that probably is not due to a heterochromatinization effect.

Animals↗
PubMed1987

Stress response in Drosophila subobscura. III. Variability of heat shock puffs.

Variability in the heat shock response has been studied in D. subobscura, both in individuals from different strains at the same moment of development and in individuals belonging to the same strain at different moments of prepupal development. The heat shock response was independent of the genic background of the individuals, whereas a variability depending on the moment of development has been obtained. In relation to this variability two kinds of heat shock puffs have been found: those induced independently of the moment of development and those induced with a response dependent on it. In both cases a differential genic response that is dependent on the temperature of treatment has been detected.

Age Factors↗
PubMed1987

Parenteral nutrition via the peritoneum with dextrose and amino acids.

We filled the peritoneal cavity of 9 rabbits through a silastic pediatric Tenckhoff-type catheter with a volume 10% of the animal's weight of an isotonic 'absorption mass' made up by a hydroelectrolytic solution to which 535 mg/dl glucose and 2.53 g/l L-amino acids were added. Then we slowly and continuously infused into it a mixture of a 50% glucose solution with a 13.3% L-amino acid solution to provide 10 +/- 0.2 g glucose and 2.18 +/- 0.24 g L-amino acid (0.334 +/- 0.039 g nitrogen) per kilogram weight in 24 h. So we mimicked the scheme and quantities of total parenteral nutrition. Osmolarity and volume of peritoneal fluid were constant throughout the experiment. In the first 4 h, glucose concentration rose to 1,407 +/- 431 mg/dl and amino acids decreased to nearly two thirds of their initial concentrations. Thereafter, both amino acid and glucose concentrations stabilized. Blood sugar rose slightly from basal 145 +/- 16 mg/dl to a maximum of 200 +/- 59 mg/dl. Plasma amino acids showed a moderate but irregular variation with increases in proline, glutamic acid, methionine, lysine and arginine concentrations, a decline of isoleucine and tryptophan concentrations and no changes for the other amino acids given. There were no variations in plasma values of sodium, potassium, chloride, urea, creatinine, osmolarity, total proteins and hematocrit. We achieved a glucose absorption of 8.72 +/- 0.94 g/kg weight (87.07 +/- 10.11% of the administered amount) and a nitrogen absorption of 303 +/- 47 mg/kg/day (91.4 +/- 14% of administered amount).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1986

Evolution of mitochondrial DNA in Drosophila subobscura.

The colonization of the New World by the Palearctic species Drosophila subobscura was first detected in 1978 in South America and around 1982 in western North America. The ensuing dramatic expansion of the species, in territory as well as numbers, provides an opportunity for studying evolution in a scale rarely possible. We have used 10 restriction endonucleases to analyze the mitochondrial DNA (mtDNA) of individuals from 23 widely dispersed localities. Only two mtDNA composite morphs have been detected in the Americas. None of the two morphs has been found in Africa, and only one in the Atlantic islands; but both are widespread in Europe, which provides no clue of the precise geographic origin of the colonizers. The amount of nucleotide-substitution polymorphism detected in D. subobscura is typical for animals, but it is greater in the Old than in the New World, presumably due to the recent colonization by a limited number of colonizers. Assuming standard evolutionary rates of mtDNA base substitution, the mtDNA morphs found in D. subobscura can be traced to a single one that existed no less than one million years ago. We argue against the inference that the D. subobscura flies now living descend from only one or a few females that lived at that time. This type of inference, which we call the "Mother Eve hypothesis," has been made to conclude that the human population went through a severe constriction about 200,000 years ago, so that all living humans descend from only one or a few women who lived at that time. The Mother Eve hypothesis is fallacious.

Journal Article↗
PubMedDate not supplied

Mitoxantrone, L-leucovorin and 5-fluorouracil: an effective and well tolerated first-line treatment for advanced breast cancer.

AIMS AND BACKGROUND: The combination of mitoxantrone plus leucovorin/fluorouracil in heavily pretreated patients with advanced breast cancer has shown significant activity and extremely good tolerability. The aim of this study was to evaluate the activity of this combination in patients not previously submitted to chemotherapy. METHODS: From May 1993 to December 1995 we treated 80 patients with advanced breast cancer with a combination of mitoxantrone, l-leucovorin and 5-fluorouracil. All patients had histologically or cytologically proven breast cancer, WHO performance status 0-3, normal hematological parameters and normal serum bilirubin. Prior chemotherapy for metastatic disease was not allowed, whereas adjuvant CMF (cyclophosphamide, methotrexate and 5-fluorouracil) or adjuvant anthracycline (doxorubicin or epirubicin) therapy was allowed; a single prior hormone treatment was permitted. Chemotherapy consisted of mitoxantrone 12 mg/m2 i.v. day 1, l-leucovorin 150 mg/m2 i.v. days 1, 2 and 3 and 5-fluorouracil 350 mg/m2 i.v. days 1, 2 and 3. The courses were repeated every 3 weeks. RESULTS: Objective response (CR + PR) was observed in 46/80 (57%) patients (95% CI, 46%-68%). Complete response (CR) was observed in 21/80 cases (26%). Response was observed in 14/24 (58%) patients with soft tissues as the dominant site of disease, in 22/34 (65%) patients with visceral involvement and in 10/22 (45%) of those with bone as the dominant site of disease. The median duration of response and survival was 9 months (range, 3-16) and 22 months (range, 2-48+), respectively. Toxicity was very manageable, with grade 4 leukopenia and thrombocytopenia in 6/80 (7.5%) and 1/80 (1.25%) patients, respectively, and negligible non-hematological toxicity. CONCLUSIONS: The combination of mitoxantrone, 5-fluorouracil and high-dose l-leucovorin is a safe and effective regimen for first-line treatment of advanced breast cancer.

Adult↗
PubMedDate not supplied

[Hypoxic encephalopathy and cortical laminar necrosis].

INTRODUCTION: Cortical laminar necrosis is characterized by destruction of the cerebral cortex, mainly of the third layer, in situations of reduced energy supply to the brain. The cerebral lesions caused are known through studies made at autopsies, but there are few descriptions in the literature of the neuroimaging changes. We report the case of a patient who suffered hypoxic encephalopathy secondary to prolonged status epilepticus, and in whom cerebral MR showed changes compatible with cortical laminar necrosis. CLINICAL CASE: A 16 year old girl who had been epileptic since infancy presented with a state of generalized tonic-clonic convulsions followed by coma. Three weeks later she was mute, had a blink reflect to threats and followed visual stimuli with eye movements but no voluntary motor or verbal response. She also showed generalized hypertonia and fine tremor of her arms, which she moved spontaneously with no asymmetry. After two months her clinical condition became stable. Cerebral MR at this time showed diffuse hypersignal of the cortex and basal ganglia in T2 and FLAIR sequences and hyposignal of the subcortical white matter associated with a marked hypersignal delimiting the grooves of convexity in T1 sequences. CONCLUSIONS: Situations of prolonged hypoxia, such as in status epilepticus, lead to necrosis of layers of the cerebral cortex. Clinically this is seen as the appearance of hypoxic encephalopathy and radiologically as characteristic alterations of neuroimaging known as cortical laminar necrosis.

Basal Ganglia↗