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Biomedical subjects

A Fernandes

Publications and source records attributed to A Fernandes.

At least 19 recordsLinked to original sources
PubMed1992

Reduced left ventricular diameters at onset of bradycardia during epidural anaesthesia.

Pathophysiologic mechanisms of bradycardia during epidural anaesthesia (L3-L4 with 1% lidocaine, 38 ml) were evaluated by studying changes in selected cardiovascular and hormonal parameters. Six of eight subjects (analgesia to T8-T10) remained circulatory stable with no significant changes in heart rate (HR), mean arterial pressure (MAP) and thoracic impedance (TI). In one of two subjects MAP decreased after 25 min from 85 to 50 mmHg (11.3 to 6.7 kPa), HR from 80 to 45 beats.min-1 while thoracic impedance increased from 25.5 to 26.5 ohm. End-systolic diameter (ESD) and end-diastolic diameter (EDD) of the left ventricle determined with echocardiography were reduced from 3.8 to 3.2 cm (17%) and 5.6 to 5.0 cm (11%), respectively. In the other subject MAP decreased after 25 min from 75 to 50 mmHg (10.0 to 6.7 kPa) and HR from 82 to 60 beats.min-1 while thoracic impedance increased from 28.8 to 29.6 ohm. ESD was reduced from 3.8 to 3.3 cm (13%), and EDD from 5.6 to 5.0 cm (11%). Both subjects recovered after infusion of saline and being placed in the head-down position. There were no consistent changes in plasma catecholamines, whereas pancreatic polypeptide increased from 5 and 3 to 152 and 69 pmol.l-1, vasopressin from 3 and 2 to 152 and 46 pmol.l-1, and aldosterone from 282 and 229 to 383 and 485 pmol.l-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Aeromonas hydrophila fulminant pneumonia in a fit young man.

A previously healthy 24 year old athletic man became ill suddenly with pneumonia the day after swimming in the sea. Despite intensive support measures in the intensive care unit he died three hours after admission and 21 hours after his first symptom. Necropsy showed bilateral haemorrhagic necrotising pneumonia. Aeromonas hydrophila was isolated from a blood culture taken at admission and from the lungs at necropsy. The infection may have come from contaminated sea water.

Adult↗
PubMed1992

[Neuroradiology in the physiopathologic diagnosis of subarachnoid hemorrhage--cerebral aneurysm].

The clinical importance of the cerebral aneurismatic lesion in well known. In Portugal we still do not have reliable statistics regarding the occurrence of the subarachnoid hemorrhage, however we can make a comparison through Kassel's and Drake's studies where they refer that annually 28,000 North-Americans suffer from subarachnoid hemorrhage attributed to the rupture of the cerebral aneurysm. This is a clinical situation that needs to be analyzed, more so because if it is not diagnosed and treated in time, it can cause a high level of morbidity and mortality. From 1984 to 1990, the authors studied 208 clinical cases of in-patients at the Santa Maria Hospital who had been diagnosed as having subarachnoid hemorrhage-cerebral aneurysm. They analyzed 172 cranium-encephalic Tomographies and 190 cerebral Angiographies. They found levels that overlapped the series already published with respect to the location of the lesion, dimensions and age groups involved. They tried to relate the presence aneurysm in the willis arterial circle with the occurrence of locoregional anatomic variants that were detected in 51% of the patients with aneurysm of the anterior communicating artery and in 33% of the cases in the posterior communicating artery. The high occurrence of serious forms of tomodensitrometric presentation should also be emphasized. As a matter of fact, 42.6% of the patients studied were grouped in degree IV of the Fisher Scale. This result translates the effort that is still required towards an early clinical and imaging diagnosis of warning hemorrhage to avoid or prevent a catastrophic hemorrhage recurrence.

Adult↗
PubMed1992

Halothane 2% for caesarean section.

During the induction-delivery interval for Caesarean section delivery, 2% halothane in pure oxygen was administered. The technique was compared to a 0.5% halothane in 50% oxygen/50% nitrous oxide anaesthesia. When a continuous infusion of oxytocin was administered, no excessive haemorrhage was seen. No maternal reminiscence was seen using 2% halothane, but awareness was recorded using 0.5% halothane in 50% nitrous oxide in 15% of the mothers. When there were no signs of preoperative fetal distress, the neonates were unaffected by the halothane concentration provided the induction-delivery interval was short. In cases of fetal distress, the administration of 2% halothane further aggravated the condition of the neonates, as indicated by lowered 1-min Apgar scores, umbilical oxygen tensions, pH and base excess values.

Adult↗
PubMed1991

A case of systemic mastocytosis; therapeutic efficacy of ketotifen.

A 68-year-old man presented with a 6-month history of fatigue, rhinorrhoea, pruritic skin lesions, left pleural effusion, ascites, oedema and weight loss of 10 kg. Investigations revealed hepatosplenomegaly, retroperitoneal lymphadenopathy, anaemia, leucocytosis with eosinophilia, hypoprothrombinaemia, hypocholesterolaemia and elevation of both gamma glutamyltransferase and alkaline phosphatase. Biopsies of a skin lesion, bone marrow and liver revealed mast cell infiltration, allowing the diagnosis of systemic mastocytosis (SM). Hydroxyzine plus ranitidine were given without success. Hydroxyzine treatment was stopped, and ketotifen was initiated; substantial symptomatic improvement was observed within 8 d. This case report indicates the effectiveness of ketotifen in the symptomatic treatment of SM.

Aged↗
PubMed1991

Squamous cell carcinoma arising in hidradenitis suppurativa.

The case reported concerns a 57-year-old man with a 35-year history of hidradenitis suppurativa lesions confined to his buttocks and recently complicated by a large, ulcerated, well-differentiated squamous cell carcinoma. Wide surgical excision and grafting, requiring temporary colostomy, were performed with no recurrence or metastasis during the following 12 months. The relevant literature is reviewed and discussed.

Buttocks↗
PubMed1990

Cardiovascular and ventilatory responses to dynamic exercise during epidural anaesthesia in man.

1. In order to evaluate the importance of afferent neural feedback from the working muscles for cardiovascular and ventilatory responses to dynamic exercise, epidural anaesthesia was induced at L3-L4. Six healthy males cycled for 20 min at 57% of maximum oxygen uptake and for 8-12 min at increasing work intensities until exhaustion at 238 +/- 30 W without as well as with epidural anaesthesia. 2. Presence of afferent neural blockade was verified by cutaneous sensory analgesia below T10-T11 and attenuated post-exercise ischaemic pressor response (45 +/- 8-24 +/- 6 mmHg). Efferent sympathetic nerves appear to be intact since basal heart rate and blood pressure as well as the cardiovascular responses to a Valsalva manoeuvre and to a cold pressor test were unchanged. 3. During dynamic exercise with epidural anaesthesia, blood pressure was lower than in control experiments; however, ventilation and heart rate were not affected. 4. The results indicate that afferent neural activity from the working muscles is important for blood pressure regulation during dynamic exercise in man but may not be necessary for eliciting the ventilatory and heart rate responses.

Adult↗
PubMed1990

Postnatal axial eye elongation in normal and visually deprived rhesus monkeys.

The influence of anomalous visual experience on the postnatal regulation of axial eye elongation was explored by raising newborn rhesus monkeys under different types of monocular and binocular deprivation and comparing their eye growth pattern with that of age-matched normal monkeys. Monocular manipulations included eyelid suture to eliminate pattern vision; continuous occlusion with an opaque lens to prevent visual experience; surgical removal of the natural lens to induce continuous blur; and correction of surgically induced aphakia with extended-wear contact lenses (EWCLs) to provide a focused image of near objects. Binocular manipulations involved correction of aphakia with an EWCL in one eye and continuous or partial occlusion of the phakic fellow eye. After monocular eyelid suture or occlusion, the deprived eyes were longer than the unmanipulated fellow eyes. Aphakic eyes, however, were shorter than their unmanipulated fellow eyes. The unmanipulated eyes followed the eye elongation pattern of age-matched normal monkeys. Binocular manipulations also resulted in differences in axial length between the two eyes. Aphakic eyes were shorter, and continuously occluded eyes were longer, than eyes of age-matched controls. After partial occlusion, however, the axial length of occluded eyes was similar to that of normal eyes. The finding that lid-sutured and occluded eyes become longer while aphakic eyes remain shorter than normal eyes suggests that additional factors besides retinal image quality control postnatal eye growth.

Animals↗
PubMed1989

Postnatal development of neuropeptide Y-like immunoreactivity in area 17 of normal and visually deprived rhesus monkeys.

Immunocytochemical methods were used to examine neuropeptide Y (NPY) immunoreactive neurons and fibers in area 17 of rhesus monkeys during the first year of life. NPY-immunoreactive (+) neurons are nonpyramidal cells which are either multipolar, bipolar, or bitufted in shape. They occur most frequently in layer 6 and the subjacent white matter, are sparser in the supragranular layers, and absent from layer 4C. Labeled somata in the supragranular layers are smaller compared to those in layer 6 and the white matter. A typical axon originates from the NPY+ soma or from a primary dendrite and frequently is varicose. Distribution and morphologies of NPY+ neurons in area 17 of infants are similar to those of adult monkeys. Thus, it seems that NPY+ neurons in rhesus monkeys are mature from birth. NPY+ fibers occur in area 17 from birth; however, they differ in density and distribution from those of older infant and adult monkeys. At birth, a prominent fiber plexus is found in the deepest part of layer 1, and another in the white matter. Immunoreactive processes are sparse in the remaining cortical gray, except for some vertical fibers extending from pia to white matter. By 4 months of age, labeled fibers form a coarse network in layers 2, 3, 5, and 6. In addition, a distinct plexus extends through layers 4B, 4A, and the lowest aspect of layer 3. Also, a thin immunoreactive fiber band is found at the bottom of layer 4C. In the remainder of layer 4C, NPY+ fibers are scant. The supragranular layers also exhibit a unique immunoreactive "snarl" of fibers. Increases in density of NPY+ processes in the older infants are gradual so that between 7 and 13 months of age, NPY+ fibers appear to have achieved adultlike densities. These observations indicate that NPY+ fibers in area 17 of newborn rhesus monkeys undergo postnatal maturation which reaches a plateau around 4 months of age. After monocular visual deprivation from birth to 4 months of age, either by eyelid suture or by occlusion with an opaque contact lens, density and distribution of NPY+ neurons and fibers, including snarls, appear similar to those of age-matched undeprived infants. Thus, disruption of the normal binocular input does not seem to arrest the maturation of the NPY system in area 17 of rhesus monkeys during a sensitive period of early postnatal development.

Animals↗
PubMed1989

Dopamine synthesis and metabolism in rhesus monkey retina: development, aging, and the effects of monocular visual deprivation.

The normal postnatal development, the influence of age, and the effects of visual deprivation on the dopamine system in the retina of rhesus monkeys were examined. The lowest level of retinal dopamine was found at birth. By 3-4 weeks of age, the dopamine concentration had more than doubled. This level remained relatively constant in the retinas of older infants and of adult monkeys up to 34 yr of age. The level of the dopamine metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) and the activity of tyrosine hydroxylase did not significantly change as a function of age during the postnatal life span. Monocular occlusion of newborn or infant monkeys for 1-15 months with opaque contact lenses resulted in decreases in the retinal concentrations of dopamine and DOPAC relative to the concentrations in the same animals' unoccluded eyes. Occlusion also resulted in a lower level of tyrosine hydroxylase activity in the retina. Monocular eyelid suture from birth to 15 months of age resulted in less consistent alterations of retinal dopamine and DOPAC levels; tyrosine hydroxylase activity, however, was consistently reduced by lid suture. Thus, dopamine synthesis and metabolism, and the ontogenetic increase of the retinal dopamine level of rhesus monkey are reduced by light deprivation.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

[Physiopathology of arterial hypertension. Significance of the renin-angiotensin-aldosterone system and structural changes].

It is presented a review of some recent aspects of the hypertension's physiopathology, namely those related with the renin-angiotensin-aldosterone system and with the cardiovascular structural changes. The large action range of the angiotensin is pointed out, in particular those actions related with the heart's and vessel's adaptation to a chronic load of pressure. In the end, the author stresses some recent references about the genetic's role on the pathogenesis of the structural changes.

Angiotensin II↗
PubMed1989

Corneal biometrics of the rhesus monkey (Macaca mulatta).

Keratometry, retinoscopy, horizontal diameter, and pachymetry were measured in adult and infant rhesus monkeys (Macaca mulatta). The adult monkeys had a mean corneal thickness of 0.47 +/- 0.03 mm (+/- standard deviation), corneal diameters of 10.6 +/- 0.5 mm, keratometry values of 51.90 +/- 1.61 diopters, and subjective refractions of 0.48 +/- 2.36 diopters. Female adult monkeys had smaller corneal diameters by 0.06 mm (P = .02) and steeper corneas by 0.77 diopters (P = .04). Infant female monkeys also had steeper corneas by 2.37 diopters (P = .05). No significant differences were found between right and left eyes in either adult or infant monkeys.

Animals↗
PubMed1989

Development of acuity in a primate model of human infantile unilateral aphakia.

We are studying infant rhesus monkeys that have been reared under various conditions of deprivation to model infantile unilateral aphakia. Grating acuity was assessed in these monkeys from birth to approximately 1 year of age using the quick acuity card procedure. We found that an uncorrected aphakic eye develops little or no pattern vision. Undercorrection or near point optical correction of an aphakic eye with an extended-wear contact lens coupled with continuous occlusion of the opposite eye sometimes results in normal development of acuity in the aphakic eye but does so only at the cost of loss of vision in the occluded eye. Fifty percent partial occlusion coupled with near-point correction of the aphakic eye results in similar development of acuity for both eyes during the time tested. Monkeys wearing near-point correction in the aphakic eye and without any occlusion of the other eye show surprisingly good residual acuities in their aphakic eyes. Based on these results we conclude that aphakic eyes should be treated by providing them with an optical correction, and that occlusion of the opposite eye should be used cautiously.

Animals↗
PubMed1988

The correction of aphakia in infants with hydrogel extended-wear contact lenses. Corneal studies.

Although hydrogel extended-wear contact lenses (EWCLs) have been used extensively in the correction of aphakia in neonates, little is known about the effects of these lenses on infant corneas. Recent studies have demonstrated that long-term contact lenses can induce endothelial morphometric changes, including an increased coefficient of variation (CV) of mean endothelial cell area. Using wide-field specular microscopy, the authors studied 11 eyes of 10 patients, 1 to 3 years of age who, after lensectomy for congenital cataracts, wore EWCLs for the correction of aphakia. Except for two corneas in which increased pachometric readings and CV developed after repeated episodes of lens loss and inflammation, the EWCL were well tolerated and associated with few complications in this study.

Aphakia, Postcataract↗
PubMed1988

Mechanisms of hemolysis induced by copper.

An excess of copper is the cause of hemolysis in a number of clinical conditions. Incubation of human erythrocyte (RBC) suspensions with copper (II) causes the formation of methemoglobin, lipid peroxidation and hemolysis. A new variant of the thiobarbituric acid (TBA) method, which minimizes the formation of interfering chromophores, was used to detect lipid peroxidation. Lipid peroxidation precedes hemolysis and the antioxidant vitamins C and E, which inhibit lipid peroxidation, also inhibit hemolysis. Consequently lipid peroxidation appears to be the cause of RBC destruction. Lipid peroxidation arises mostly from the oxidation of oxyhemoglobin by copper as it is inhibited in RBCs with carbon monoxyhemoglobin or methemoglobin. A direct interaction of copper with the red cell membrane seems to play only a minor role. Copper effects depend on the presence of free SH groups. Lipid peroxidation is probably initiated by activated forms of oxygen as it is increased by an inhibitor of catalase and reduced by hydroxyl radical scavengers. With higher copper concentrations hemolysis is greater: its mechanism appears different as lipid peroxidation is smaller but hemoglobin alterations, namely precipitation, are more pronounced.

Ascorbic Acid↗
PubMed1987

Alcohol interactions with lipids: a carbon-13 nuclear magnetic resonance study using butanol labeled at C-1.

The interactions of carbon-13 enriched butanol with dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) were studied using C-13 nuclear magnetic resonance. It was found that above the gel to liquid crystal phase transition the resonance from the butanol could be resolved into two signals with similar chemical shifts but different T1 values and line widths. In contrast, only one narrow resonance was observed for ethanol, which has considerably less solubility in the lipids than butanol. Thermodynamic analyses of the effects of butanol on the phase transition temperature predict much greater solubility or butanol when the lipid is above the phase transition temperature than when it is below. It was concluded that the two butanol resonances represent two slowly exchanging populations, the free butanol in the aqueous phase and butanol dissolved in the liquid crystalline region of the lipid. No bound butanol was detected below the gel to liquid crystal phase transition. Relaxation studies were performed on the resonance of the bound butanol in DPPC and DMPC, including measurements of T1, line width, and nuclear Overhauser enhancement. Theoretical analysis of the relaxation parameters indicates that the lipid-bound alcohol has very high mobility within the fluid lipid bilayer. The data are consistent with butanol being present at the aqueous boundary or head group region of the lipid.

1,2-Dipalmitoylphosphatidylcholine↗