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Biomedical subjects

A Lucas

Publications and source records attributed to A Lucas.

At least 181 records · Page 10Linked to original sources
PubMed1994

Does early nutrition in infants born before term programme later blood pressure?

OBJECTIVES: To test whether nutrition early in infants' development programmes later blood pressure and whether the reported relation between low birth weight and later high blood pressure is due to poor nutrition or growth before full term. DESIGN: Prospective randomisation of preterm infants to early diets differing greatly in nutrient content in four parallel multicentre trials, with blinded follow up 7.5-8 years later. SETTING: Neonatal units at Cambridge, Ipswich, King's Lynn, Norwich, and Sheffield. SUBJECTS: 758 children weighing under 1850 g at birth. MAIN OUTCOME MEASURE: Blood pressure at age of 7.5-8 years. RESULTS: There were major differences in nutrient intake from randomised diets (preterm formula v standard formula and preterm formula v donor breast milk; in each case with or without mother's milk), but follow up showed no differences in later blood pressure. Individual subjects showed large variation in protein and energy intakes and in growth performance, including degrees of growth failure seldom seen in utero, but these factors were also unrelated to later blood pressure. CONCLUSION: Extremes of nutritional intake and growth performance in preterm infants do not programme later blood pressure at 7.5-8 years of age. These findings do not support the hypothesis that high blood pressure has early nutritional origins. We suggest that the long term rise in blood pressure reported in individuals who had low birthweight (at full term) is not, as previously speculated, due to poor fetal nutrition or growth as such.

Blood Pressure↗
PubMed1994

Iliac aneurysm in a child complicating umbilical artery catheterization.

We report a case of an iliac artery aneurysm in a 9-year-old girl due to Staphylococcus aureus infection of an umbilical arterial catheter inserted at birth. After resection-anastomosis of the iliac artery the postoperative course was uneventful and hemodynamic data remain normal at 2 years. A review of the literature indicates that the prognosis of infective aortoiliac aneurysm is poor in children, except when the aneurysm is located solely in the iliac artery. Arterial continuity should be restored as late as possible after infection using a technique consistent with normal growth of the artery in the child.

Catheterization, Peripheral↗
PubMed1994

A prospective randomized double-blind trial of bolus urokinase in the treatment of established Hickman catheter sepsis in children.

BACKGROUND: The incidence of Hickman catheter sepsis is 10% to 40%, with resultant catheter loss in one third of infections. Urokinase causes dissolution of colonized intracatheter fibrin thrombi and may improve salvage. STUDY AIMS: To evaluate the efficacy of 12-hour-interval slow-push urokinase infusion in addition to standard antibiotic therapy in the treatment of catheter sepsis in a pediatric oncology population. METHODS: A two-arm randomized double-blind trial was undertaken, with catheter salvage rate as the end point. Patients with Hickman catheter sepsis were randomized after culture data confirmed the diagnosis. The study drug was administered by a slow intravenous push and given at 12-hour intervals for a total of four doses. The catheters were aspirated after 1 hour. RESULTS AND CONCLUSIONS: The trial was stopped after 41 patients were entered into the study; 18 patients received a placebo, and 23 received the urokinase. In the placebo group, six catheters were lost; in the urokinase group, eight were lost. The rate of bacterial clearance was equivalent for both. After administration of the study drug, each group had three episodes of fever and chills; two of these resulted in hypotension (one in each group). The authors conclude that slow-push urokinase infusion during established Hickman catheter sepsis does not result in improved catheter salvage or bacterial clearance. Slow intravenous push infusions in this setting may provoke hemodynamic instability even after initiation of antibiotics.

Bacteria↗
PubMed1994

Adjusting milk intake for body size in early infancy.

Energy intake and expenditure are related to body size and body composition and therefore must be taken into consideration when comparing individuals. Previous work has typically expressed energy metabolism variables per kilogram body weight or per kilogram fat-free mass. However this may not remove the effect of body size entirely. In infancy milk volume intake is usually expressed in a similar manner which may not be entirely appropriate. The most appropriate method of expressing milk volume intake relative to body weight and fat-free mass was investigated in 20 normal breast-fed infants at 6 weeks of age. Regression analysis revealed that the relationship between milk intake and body weight could be adjusted for by expressing milk intake per kg0.68, and that the relationship between milk intake and fat-free mass could be adjusted for by expressing milk intake per kg0.54. These values are not significantly different to 0.50 which is the square root of body weight. It is suggested that in studies of energy metabolism in infancy the expression of milk intake per kg0.50 should be used as the most appropriate adjustment for removing the influence of body size upon milk intake, in the first few months of life.

Body Constitution↗
PubMed1994

Influence of early diet on outcome in preterm infants.

Despite intensive research in infant nutrition over the past 50 years, uncertainty exists in nearly every major area of practice. A key factor in this uncertainty has been the lack of knowledge on whether diet or nutritional status in early life has a long-term or permanent influence on health, growth or performance. The possibility that early nutrition has long-term consequences in man has been much debated. There have been limited opportunities to perform formal randomized studies on the effect of early nutrition in humans and many studies have been flawed by problems with study design. Infants born preterm are a special group. At the start of our study in 1982, evidence on which to base choice of diet was inconsistent and related only to short-term outcome, and diets available for such babies differed greatly in nutrient content. In this group it was both ethical and practical to conduct a formal, randomized trial of early diet and outcome and the results were clearly needed for management decisions. We have undertaken a long-term prospective outcome study on 926 preterm infants randomly assigned to the diet received in the neonatal period. Surviving children have been followed at 9 months, 18 months and now 7.5-8 years of age. Our findings suggest that human milk may contain factors which promote brain growth or development and also bone mineralization later in childhood. Outcome data from the randomized trials show that a very brief period of dietary manipulation (on average for the first 4 weeks of life) influences later development.

Bone Density↗
PubMed1994

Size at birth and later blood pressure.

Adults who were small at birth have been reported to have higher systolic blood pressure and risk of ischaemic heart disease in later life. Conversely, in 616 subjects of less than 34 weeks' gestation and 1850 g birth weight, systolic and diastolic blood pressures at 7.5 to 8 years of age decreased with decreasing weight for gestational age and were not related to birth weight. These data do not support the view that fetal growth retardation before 34 weeks programmes for increased blood pressure in later life.

Blood Pressure↗
PubMed1994

A randomised multicentre study of human milk versus formula and later development in preterm infants.

Whether breast milk influences later neurodevelopment has been explored in non-randomised studies, potentially confounded by social and demographic differences between feed groups. Here in a strictly randomised prospective multicentre trial, Bayley psychomotor and mental development indices (PDI and MDI) were assessed at 18 months postterm in survivors of 502 preterm infants assigned to receive, during their early weeks, mature donor breast milk or a preterm formula. These diets were compared as sole enteral feeds or as supplements to the mother's expressed breast milk. No differences in outcome at 18 months were seen between the two diet groups despite the low nutrient content of donor milk in relation to the preterm formula and to the estimated needs of preterm infants. These results contrast with those reported from our parallel two centre study that compared infants randomly assigned a standard term formula or the preterm formula during their early weeks; those fed standard formula, now regarded as nutritionally insufficient for preterm infants, were substantially disadvantaged in PDI and MDI at 18 months post-term. It is shown here that infants from that study fed solely on standard formula had significantly lower developmental scores at 18 months than those fed on donor breast milk in the present study; yet the standard formula had a higher nutrient content than the donor milk. Thus, donor milk feeding was associated with advantages for later development that may have offset any potentially deleterious effects of its low nutrient content for preterm infants. As these outcome advantages were not confounded by the social and educational biases usually associated with mothers' choice to breast feed, our data add significant support to the view that breast milk promotes neurodevelopment.

Child Development↗
PubMed1994

Relationship between lipoprotein profile and urinary albumin excretion in type II diabetic patients with stable metabolic control.

OBJECTIVE: To assess lipids and lipoprotein composition and the relationship between lipoprotein abnormalities and urinary albumin excretion (UAE) in select type II diabetic patients with stable metabolic control. RESEARCH DESIGN AND METHODS: Fifty-five type II diabetic patients and 55 healthy control subjects both with a body mass index < 30 kg/m2 were studied. Patients were classified according to their level of UAE as normoalbuminuric (n = 37), microalbuminuric (n = 11), and macroalbuminuric (n = 7). In all cases, serum creatinine and albumin concentrations were in the normal range. RESULTS: Normoalbuminuric patients showed increased triglyceride (TG) contents in intermediate-density lipoprotein (IDL) (P < 0.01), low-density lipoprotein (LDL) (P < 0.001), and high-density lipoprotein (HDL) (P < 0.001) compared with control subjects. Lipoprotein concentration in microalbuminuric patients did not differ from that of normoalbuminuric patients. On the other hand, patients with macroalbuminuria showed a significant increase in IDL cholesterol (P < 0.01) and IDL (P < 0.01), LDL (P < 0.05), and HDL TGs (P < 0.01) compared with the other groups. Diabetic patients with nephropathy, both microalbuminuric and macroalbuminuric, tended to have higher mean lipoprotein(a) (Lp[a]) concentrations than normoalbuminuric patients and control subjects. A strongly positive correlation was observed between UAE and serum TGs (r = 0.56) and very-low-density lipoprotein (r = 0.55), IDL (r = 0.52), LDL (r = 0.54), and HDL TGs (r = 0.52). CONCLUSIONS: Lipoprotein alterations observed in diabetic patients, specifically IDL abnormalities and a tendency toward high Lp(a) levels, which are more marked in those with increased UAE, may contribute to the excess of cardiovascular disease in type II diabetic patients, particularly those with nephropathy.

Aged↗
PubMed1994

[Free latissimus dorsi flap revascularized by double venous graft on the femoral trifurcation in the treatment of lumbar radionecrosis. Apropos of 2 cases].

Two patients were operated in 1989 and 1992 for lumbar chronic osteoradionecrosis (toxi-infection collapsus in one of the two cases). Conventional coverage procedures (skin graft, local flaps) or distally based latissimus dorsi musculo-cutaneous flap (second case) were attempted but failed. So we realised in a one stage procedure a free musculo-cutaneous flap in the case no. 1 and a free muscular flap, later skin grafted, in the case no. 2. Venous and arterial bypass were provided by 40 cm long saphenous veins harvested from the thighs, and allowed to reach the lumbar site with proximal anastomosis performed on the femoral artery. The results were considered to be excellent. That short experience shows that long venous bypass with microsurgical free transfer can be safely performed. This results in an extremely high flow shunt.

Adult↗
PubMed1993

Lipoprotein composition in the insulin-deficient non-acidotic phase of type I diabetic patients and early evolution after the start of insulin therapy.

Lipoproteins, including intermediate density lipoproteins and lipoprotein(a), and apolipoproteins A-I, B, C-II, C-III and E, were studied in 13 newly-diagnosed type I diabetic patients with severe insulinopenia without dehydration or acidosis. At baseline, the main finding was a significant increase in serum triglycerides due to raised triglyceride concentrations in all lipoproteins, particularly triglyceride-rich lipoproteins. Cholesterol concentrations were slightly increased in lipoproteins and led to a significant increase in serum cholesterol. Two days after the start of insulin therapy, lipoprotein profiles had normalized except for the LDL triglyceride contents, which remained significantly increased on the fifth day of treatment. No significant modifications were observed in lipoprotein(a), apolipoproteins A-I and E concentrations throughout the study. However, serum apolipoproteins B, C-II and C-III were increased at baseline and fell to normal levels 2 days after the start of insulin therapy. On the other hand, apolipoprotein C-II/C-III ratios in high and very low density lipoprotein, showed no significant differences at baseline compared with controls, suggesting that an apolipoprotein C-II deficiency or apolipoproteins Cs imbalance can be ruled out. In conclusion, significant lipoprotein abnormalities were observed in the insulin-deficient state of type I diabetes mellitus; insulin therapy normalizes the lipoprotein profile in two days, except for low density lipoprotein triglyceride contents which remain increased at the fifth day.

Adolescent↗
PubMed1993

[The usefulness of the teriparatide acetate (Parathar) infusion test in the diagnosis of pseudohypoparathyroidism].

In pseudohypoparathyroidism there is a resistance to the action of the parathormone in its target organs. Patients with this disease show clinical and laboratory data of hypoparathyroidism with normal or high levels of parathormone. Three types of pseudohypoparathyroidism are known according to the site in which the disorder is localized, within the complex formed by the cell receptor for the hormone and the adenylate cyclase systems of the cell membrane: Ia, Ib and II. The response of plasmatic and urinary cyclic AMP to the administration of parathyroid hormone may be useful to establish the type of pseudohypoparathyroidism presented in determined patients. Three cases of pseudohypoparathyroidism in whom an intravenous stimulation test with the synthetic 1-34 fragment of the human parathormone [teriparatid acetate (PARATHAR)] are presented. These patients were diagnosed according to the responses of cyclic AMP of type I pseudohypoparathyroidism. The methodology followed for the study and the results obtained are commented.

Adult↗
PubMed1993

Development of surrogate substrates for juvenile hormone esterase.

Twenty-nine thioester compounds were synthesized to test their effectiveness as surrogate substrates for the insect enzyme, juvenile hormone esterase (JHE). Substrates were designed that resembled the endogenous substrate juvenile hormone (JH), with one common factor being a thioester instead of carboxyl ester found in JH. The principle of the spectrophotometric assay is based on a modification of Ellman's method. Characterization of the substrates showed that replacement of the carbon atom by a sulfur or oxygen beta to the carbonyl of the acyl group of the substrates resulted in an approximate five- to sixfold increase in the rate of hydrolysis by JHE. The specific activities of JHE, porcine liver carboxylesterase, and acetylcholinesterase were determined for the surrogate substrates. While JHE and porcine liver carboxylesterase hydrolyzed several of the substrates, acetylcholinesterase did not produce any detectable hydrolysis of the substrates. Michaelis-Menten kinetic parameters of the surrogate substrates when compared to a previously reported partition assay, utilizing radiolabeled [3H]JH III, indicated that the surrogate substrates have lower affinity as indicated by higher Km values but are more easily hydrolyzed (Vmax) by JHE. Furthermore, optimal reaction conditions for substrate hydrolysis and the spectrophotometric reaction were determined. In addition, first order rate constants for base hydrolysis and critical micelle concentrations were determined for several surrogate substrates. The spectrophotometric assay was also compared with a Vmax and research spectrophotometer, and these two instruments produced almost identical slopes. The relative potency of four transition state inhibitors of JHE was found to be similar with those of the surrogate substrates and the [3H]JH III substrate.

Acetylcholinesterase↗
PubMed1993

Laser induced fluorescence identification of sinoatrial and atrioventricular nodal conduction tissue.

UNLABELLED: Transcatheter ablation of nodal tissue is used for the treatment of arrhythmia resistant to medical therapy. We have investigated the use of laser induced fluorescence spectroscopy for the in vitro recognition of nodal conduction tissue. Twelve fresh human necropsy specimens (< 48 hours) were obtained from sinoatrial node and atrioventricular node areas. Spectra were recorded during excitation at 308 nm (XeCl excimer laser, 1.5-2.0 mJ/pulse, 10 Hz). Ech area examined was marked for subsequent histologic examination. Four hundred eleven spectra were obtained, of which 37 contained nodal conduction tissue (21 sinoatrial, 16 atrioventricular node). Normalized fluorescence emission intensity from these areas was compared with that of surrounding endomyocardial tissue at 18 wavelengths and 35 ratios of fluorescence intensity at selected wavelengths. Spectra recorded from nodal tissue could be clearly distinguished by a visible decrease in fluorescence emission intensity at wavelengths from 440 to 500 nm (P < 0.0006 at 450 nm), peak area, and peak width when compared to that of adjacent atrial endomyocardial tissue. Nodal conduction tissue was also distinguished from ventricular endocardium (14 spectra) by an increase in fluorescence emission at 430 to 550 nm (P < 0.0001). The specificity was 73% and 88% and the sensitivity was 73% and 60% for sinus nodal and atrioventricular nodal conduction tissue identification, respectively. A ratio of fluorescence emission intensity > 1.3 for 380/475 nm was able to detect nodal conduction tissue (P < 0.001). CONCLUSION: Laser induced fluorescence can differentiate nodal conduction tissue from atrial and ventricular endocardium and may provide a new diagnostic tool for the recognition and subsequent ablation of nodal conduction tissue.

Adolescent↗