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Biomedical subjects

A Lucas

Publications and source records attributed to A Lucas.

At least 307 records · Page 17Linked to original sources
PubMed1986

[The development of tinnitus in the postoperative period of otospongiosis].

Correlation between tinnitus and audiometric loss, modification of tinnitus by medical or surgical treatment, allow to suspect the origin of tinnitus due to otospongiosis and to give the patient a practically always confirmed prognosis. Audiometric localization of tinnitus is essential, as it is the best clue to etiology, treatment and prognosis of otospongiosis tinnitus. As far as irreducible tinnitus are concerned, as anxiety is the most pejorative parameter, not discouraging the patient is very important.

Audiometry↗
PubMed1985

The stimulatory effects of prostaglandins on the melanophores of the lizard, Anolis carolinensis.

The melanosome dispersing activity of prostaglandins PGE1, PGE2, PGF1 alpha, PGF2 alpha, PGI2 and 6 beta PGI, was tested on the melanophores of Anolis carolinensis. Only PGE2 and PGE1 were active and while PGE2 was the most potent and acted synergistically with alpha-MSH, PGE1 was additive with alpha-MSH. Arachidonic acid also stimulated melanosome dispersion but its effect was blocked by indomethacin suggesting an action through its conversion to PGE1 or PGE2. The effect of alpha-MSH, on the other hand, was unaltered by indomethacin which suggests that alpha-MSH stimulated melanosome dispersion does not depend upon prostaglandin synthesis. Thus, while some prostaglandins may interact with alpha-MSH to stimulate melanosome dispersion they are unlikely to mediate its action.

Animals↗
PubMed1985

The effects of two extremes of dietary intake on protein accretion in preterm infants.

A comparison has been made of protein accretion and growth in premature infants fed banked drip breast milk (BBM) or a preterm formula (PF). Protein accretion was calculated from the difference between dietary nitrogen intake and output in urine and stools, measured in a nutrient balance study. As expected, only the infants fed PF achieved the intrauterine growth rate. However, whilst weight gain in infants fed BBM was 71% of that in the group fed PF, the rate of protein deposition was less than 50%. As a result, the protein concentration in new tissue of infants fed BBM averaged 32% less than in those fed PF and 21% less than the lower end of the range reported to occur in utero. We speculate that infants fed BBM have an abnormally low protein concentration in their lean body mass.

Growth↗
PubMed1985

Susceptibility of riboflavin and vitamin A in breast milk to photodegradation and its implications for the use of banked breast milk in infant feeding.

Up to 50% of the riboflavin and up to 70% of the vitamin A in human drip breast milk samples were destroyed during controlled exposure to daylight, either in translucent polythene bottles, or where the milk was pumped through naso-gastric tubing from a syringe to mimic the conditions of enteral feeding. Losses were also observed in milk which was exposed to standard phototherapy illumination under conditions similar to those encountered in the ward, and in this case riboflavin was destroyed to a greater extent than vitamin A. Photodegradation of riboflavin may contribute to the high incidence of biochemical riboflavin deficiency reported in preterm infants receiving breast milk without vitamin supplements. The implications of these findings for feeding high risk term and preterm infants on donor milk are discussed, and the use of low actinic vessels and tubing to minimise photodegradation is recommended.

Female↗
PubMed1985

Measurement of urinary constituents and output using disposable napkins.

A procedure for estimating 24 hour urine output in infants using disposable nappies has been validated. In addition, it has been shown experimentally that the urinary concentrations, and hence 24 hour outputs of a range of constituents (sodium, potassium, nitrogen, creatinine, urea, amino acids, and deuterium oxide), may be measured accurately using samples of urine obtained from nappies. It is concluded that the urine collection procedure described has several major advantages over traditional urine bag methods, and has a wide application in clinical practice and research.

Humans↗
PubMed1985

Gastrointestinal peptides and the adaptation to extrauterine nutrition.

The adaptation to extrauterine nutrition involves complex physiological changes at birth which may be regulated by genetic endowment; enteral nutrients, secretions, and bacteria; and endogenous hormones and exogenous hormones in breast milk. The hypothesis is explored that enteral feeding after birth may trigger key adaptations in the gut and in metabolism partly through the mediation of gastrointestinal hormone secretion. Gut peptides are found in the early human fetal gut and by the second trimester some are found in high concentrations in the fetal circulation and amniotic fluid. Major plasma hormonal surges occur during the neonatal period in term and preterm infants: notably in enteroglucagon, gastrin, motilin, neurotensin, gastrointestinal peptide, and pancreatic polypeptide. These events do not occur in neonates deprived of enteral feeding. A progressive development of dynamic gut hormonal responses to feeding is observed. The pattern of gut endocrine changes after birth is influenced by the type and route of feeding. Potential pathophysiological effects of depriving high risk neonates of enteral feeding are considered. It is speculated that infants committed to prolonged total parenteral nutrition from birth may benefit from the biological effects of intraluminal nutrients used in subnutritional quantities.

Adaptation, Physiological↗
PubMed1985

Utility of pneumonotomy in the treatment of cavitary lung disease.

Three patients were judged to be prohibitive operative risks despite the need for urgent drainage of cavitary pulmonary lesions. Cavernostomy was performed in each case, with a satisfactory long-term outcome in two patients. The third patient recovered from his pulmonary insult, but died much later, secondary to an unrelated illness. One patient had a purulent lung abscess due to aspiration, one had atypical tuberculosis resistant to all antibiotics, and the third patient experienced massive hemoptysis from a tuberculous cavity. Two-stage procedures were utilized in the first two patients, while urgent operation in the third patient was facilitated by adhesions from a previous thoracotomy and pleural infection. Care must be taken to minimize endobronchial and pleural contamination by meticulous attention to detail during the performance of percutaneous tube drainage. There are relatively few indications for percutaneous drainage of cavitary pulmonary lesions in this antibiotic era. However, certain clinical situations should prompt consideration for a pneumonotomy. These include a severely septic or debilitated patient who is unresponsive to medical management, the presence of resistant pathogens in a compromised host, and the presence of severe adhesive pleuritis which may prohibit an expeditious thoracotomy and resection for massive hemoptysis.

Adult↗
PubMed1985

Increased tolerance to cold induced by hyperoxia in hypothermic dogs.

In dogs acutely immersed in cold water (8-13 degrees C) oxygen uptake increased and rapidly reached a maximum value (CV02 Max). A few minutes after the start of immersion colonic temperature began to fall more or less rapidly depending on the dog but always in a linear fashion. Twenty min. after the start of immersion the inspired air was switched from air to a 60% O2/40% N2 gas mixture. The switch to the hyperoxia gas mixture slowed down or even stopped the fall in colonic temperature. Concomitantly a lowering of plasma lactate concentration was observed. It may be concluded that hyperoxia improves the cold tolerance of dogs exposed to a severe cold stress. This improvement may be due to a direct effect of hyperoxia on cellular metabolism. However other effects induced by hyperoxia cannot be ruled out.

Animals↗
PubMed1985

[Prognosis for tinnitus after surgery for otospongiosis].

Correlation between tinnitus and audiometric loss and modification of the former by both surgical and medical treatment provide sufficient data to suggest its origin and to give the patient a prognosis confirmed in practically every case. Audiometric localization of the tinnitus is essential, since this allows establishment of the etiology, treatment and prognosis of the symptom. When tinnitus is irreversible, the hope of a possible recovery must be given to the patient to avoid the inevitable anxiety produced.

Adjustment Disorders↗
PubMed1984

Latent anaphylactic sensitisation of infants of low birth weight to cows' milk proteins.

Latent systemic anaphylactic sensitisation to cows' milk was assessed in 61 preterm infants who were randomly assigned to receive either a special formula for preterm infants based on cows' milk or banked breast milk or one or other of these as a supplement to maternal milk. A single sample of venous blood was taken near to the time of discharge from the neonatal intensive care unit, and the histamine release by blood basophils in response to in vitro challenge with cows' milk and anti-IgE was measured. Compared with the blood from infants fed on human milk, that from infants fed on preterm formula showed a significant increase in histamine release to challenge with cows' milk, the response being greater in blood from infants of lower birth weight and gestational age. A smaller but significant increase in blood histamine release with anti-IgE challenge was observed in the group fed on preterm formula. Infants of low birth weight fed on preterm formula based on cows' milk may develop latent systemic sensitisation more rapidly than infants born at term. The clinical importance of this requires further investigation.

Anaphylaxis↗
PubMed1984

Multicentre trial on feeding low birthweight infants: effects of diet on early growth.

A large multicentre study on the short and long term clinical and developmental outcome of infants randomised to different diets is being undertaken. This report represents an interim analysis of the early postnatal growth performance of an unselected population of 194 preterm infants (gestation, mean (SD) 31 . 0 (2 . 9) weeks; birthweight, mean (SD) 1364 (294) g), both ill and well, examined in two (of four) parallel trials. One trial compared banked breast milk with a new preterm formula (primary trial); the other compared these diets as supplements to maternal milk (supplement trial). A major dietary effect on the number of days taken to regain birthweight and subsequent gains in weight, length, and head circumference was observed in the primary trial. Infants fed banked breast milk and weighing less than 1200 g at birth took a calculated additional three weeks to reach 2000 g compared with those fed on the preterm formula. A significant influence of diet on body proportions was seen in the relation between body weight, head circumference, and length. Similar though smaller differences in growth patterns were seen in the supplement trial. By the time they reach 2000 g, infants of birthweights 1200 to 1849 g fed on banked breast milk and infants below 1200 g fed on either banked breast milk or maternal milk supplemented (as necessary) with banked breast milk, fulfilled stringent criteria for failure to thrive (weight less than 2 SD below the mean for age). Only infants fed the preterm formula as their sole diet had maintained their birth centile by discharge from hospital. The misleading nature of comparisons between extrauterine and intrauterine steady state weight gains is emphasised.

Body Height↗
PubMed1984

Preterm milk as a source of protein for low birthweight infants.

A total of 588 samples of 24 hour collections of preterm milk obtained during the first month of lactation from 58 mothers of low birthweight infants have been analysed for total nitrogen content. In addition to the expected decline in milk protein content (total nitrogen X 6 X 38) seen with postnatal age, a strong negative correlation between milk protein and milk volume output has been shown. Thus, the greater the volume produced, the smaller the chance that preterm milk contains a sufficiently high protein concentration to meet the calculated requirements of low birthweight infants (given the constraints on the infant's volume intake). Postnatal age and the infant's body weight are identified as additional factors which influence the likelihood that theoretical protein needs will be met. It is speculated that the high protein content seen in preterm milk may not necessarily reflect a unique secretory ability of the mammary gland in mothers delivering preterm but may relate more to the low volume of milk produced by many donors.

Birth Weight↗
PubMed1984

Transient riboflavin depletion in preterm infants.

Biochemical riboflavin status was measured in 68 preterm infants who were receiving either human milk or a preterm infant formula (containing riboflavin, 1.8 mg/l) during the first few weeks of life. The relation between riboflavin status, type of diet, and time of introduction of a multivitamin supplement containing riboflavin was analysed and the duration of phototherapy was recorded. Those who received the multivitamin supplement on or before day 7 of life seldom became deficient and no significant difference between diets was seen in this group. Of those who received the supplement after day 7, human milk fed infants commonly developed abnormal riboflavin status (18 out of 23 infants) compared with a small and significantly lower incidence in the formula fed group. Dietary effects on riboflavin status seemed to outweigh in importance those of phototherapy. It is concluded that the riboflavin content of human milk, which may be lowered by photodegradation, is not sufficient to ensure normal biochemical status in preterm infants. The larger amounts provided by a multivitamin supplement or by a preterm infant formula may, however, prevent biochemical deficiency. The desirability (and safety) of routine riboflavin supplementation of preterm infants is discussed.

Age Factors↗