Search PubMed⌕ Search

Biomedical subjects

D Segura

Publications and source records attributed to D Segura.

26 records · Page 2Linked to original sources
PubMed1993

Muscle carnitine deficiency and lipid storage myopathy in patients with mitochondrial myopathy.

Abnormal carnitine distribution in muscle was found in 22 of 77 patients (29%), with mitochondrial myopathy. Furthermore, total (TC) and free (FC) carnitine levels in muscle were lower in patients than in controls (P < 0.01). Muscle long-chain acylcarnitines (LCAC) were significantly increased in these patients (P < 0.01). Muscle carnitine deficiency was found in 31.5% of patients with lipid storage myopathy (LSM) and in 25.6% of patients with ragged-red fibers (RRF). Therefore, carnitine deficiency can be found in patients with mitochondrial myopathy even in the absence of LSM. Muscle levels of TC and FC were lower in patients with respiratory chain defects than in those with normal respiratory chain (P < 0.01). In contrast, LCAC levels were significantly increased (P < 0.05). Carnitine levels did not differ significantly, among patients with different respiratory-chain defects. Consequently, these patients, owing to their biochemical block, reduce progressively the muscle carnitine pool and subsequent LCAC rise, due to long-chain fatty acid (LCFA) accumulation.

Adolescent↗
PubMed1991

[Complex I (NADH coenzyme-Q-reductase) deficiency, MELAS syndrome and hypertrophic cardiomyopathy].

A 24-year-old male had a deficiency of the complex I (NADH coenzyme-Q-reductase) of the mitochondrial respiratory chain, which clinically presented as a mitochondrial encephalomyopathy, with lactic acidosis and stroke-like episodes (MELAS syndrome). The encephalopathic episodes were preceded by migraine and were characterized by focal deficit signs, motor partial seizures and hypodense areas in the CT scan. An echocardiographic diagnosis of hypertrophic cardiomyopathy without intracavitary thrombi was made. It is suggested that hypertrophic cardiomyopathy is caused by the mitochondrial abnormalities that have been reported in the myocardium, and that migraine and cerebral infarctions are associated with abnormalities in the mitochondria from the endothelium and smooth muscle fibres of the cerebral small arteries and arterioles.

Acidosis, Lactic↗
PubMed1984

Sequential morphological and functional changes in kaolin-induced hydrocephalus.

An experimental model of kaolin-induced hydrocephalus in the dog was studied in order to evaluate the progress of ventricular dilatation and the communications between the ventricular system and the subarachnoid space. Skull and spine radiological studies were obtained after metrizamide intraventricular injection, and the baseline ventricular pressure and cerebral pulse pressure amplitude were measured in anesthetized animals. Intracranial compliance and resistance to drainage of cerebrospinal fluid were calculated by means of bolus injection test. Light and scanning electron microscope studies were done at different developmental stages of hydrocephalus. With these experimental parameters, two successive phases were seen: an initial acute hypertensive hydrocephalus (H1) with high resistance, low compliance, severe ependymal damage, and subependymal edema; and a late chronic normotensive hydrocephalus (H2) with little resistance increase, normal compliance, epithelial regeneration, and subependymal gliosis. Both the H1 and H2 stages showed an increase in the cerebral pulse pressure amplitude.

Animals↗
PubMedDate not supplied

[Comparative study between propofol and thiopental for anesthesia induction in surgery of short duration].

To compare anesthetic characteristics of thiopental and propofol in short duration surgical interventions, we have studied 40 patients undergoing gynecologic and proctologic surgery. Patients were randomly assigned to two groups receiving 2.5 mg/kg of propofol or 5 mg/kg of thiopental. In both groups, arterial hypotension of comparable intensity occurred. Heart rate was significantly higher in thiopental anesthesia. Postanesthesia recovery was significantly more rapid with propofol. Some of these results can be influenced by the different immediate premedication (atropine and diazepam in thiopental group) and duration of anesthesia.

Adult↗
PubMedDate not supplied

[Synthesis, function, and evolutionary origin of secondary metabolites produced by micro-organisms].

The microbial secondary metabolites are compounds with a wide range of chemical structures, produced mainly by actinomycetales and some fungi, usually in the late growth phase. Although a high proportion of this metabolites are antibiotics, there are also examples with pigment, herbicide and surfactant properties. Its function has been correlated to bacterial pathogenicity and cellular differentiation, however, properties dealing with chelation, hormonal and antitumor activities as well as nutritional reserve have been also reported. As in other examples of cellular compounds, the secondary metabolites are produced from low molecular weight precursors. For this purpose, specific biosynthetic pathways are utilized and regulated by processes which generally affect either the activity or the synthesis of the enzymes involved in it. Considering the secondary metabolites apparently are dispensable compounds, there are difficulties to explain their existence from an evolutionary point of view. Explanations to their existence have gone from laboratory artifacts to those conferring them an adaptative value in the past. It seems that they were maintained due to selective advantages to the producer microorganisms and probably, their sometimes complex biosynthetic pathways, have emerged from primary metabolites and evolved later independently by random mutation, amplification and genetic transfer.

Adaptation, Physiological↗
PubMedDate not supplied

[Comparative study of intravenous anesthesia with propofol in continuous perfusion and neuroleptanalgesia in traumatology surgery].

OBJECTIVE. To study propofol as the single agent for both anesthetic induction and maintenance with respect to quality of anesthesia, hemodynamic effects, quality of recovery and analgesic requirements in comparison with neuroleptoanesthesia as the technique of reference. PATIENTS AND METHODS. We selected 2 homogeneous groups of 15 ASA I-III patients undergoing traumatological surgery. Patients were premedicated with bromazepam 3 mg p.o. and droperidol 0.03 mg/kg prior to induction. Induction was achieved with propofol 1.5-2.5 mg/kg in group I (GI) and with sodium thiopental 4-5 mg/kg in group II (GII). Maintenance was by continuous infusion of propofol 6-12 mg/kg in GI and with droperidol 0.15 microgram/kg/h and 50% N2O/O2 in GII. Both groups received fentanyl 4 micrograms/kg/h. Neither analgesia nor curarization were antagonized pharmacologically. Variables recorded were time and quality of anesthetic induction, mean duration of anesthesia, anesthetic education time, time until orientation and time of residual analgesia. Hemodynamic parameters were recorded for both groups at baseline, after induction, at intubation, at 2 and 5 min after intubation, at the start of surgical incision, 30 min after start of incision, and at the end of surgery. Results for the two groups were compared, as were results at the various moments of measurement within groups.

Adult↗