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Biomedical subjects

J C Sinclair

Publications and source records attributed to J C Sinclair.

At least 37 records · Page 2Linked to original sources
PubMed1988

The neonatal intensive care unit: organization of care of the low-birthweight infant.

A large and growing body of evidence based in large part on randomized clinical trials of therapy has established the efficacy of neonatal intensive care. The efficacy of neonatal intensive care is "leveraged" by highly efficient regional programs for ascertainment and referral of patients at risk. Thus the impact of neonatal ICUs is keenly felt in the community. The population incidence of ROP and its sequelae may be expected to rise as infants at highest risk--those at the border of viability--survive in increasing numbers.

Community Health Services↗
PubMed1986

Energy balance in low birth weight infants fed formula of high or low medium-chain triglyceride content.

We tested the effect on energy balance of the partial substitution of medium-chain for long-chain triglycerides in the diet of growing low birth weight infants. Fifteen infants were studied in a randomized double-blind crossover clinical trial in which each infant was fed each of two formulas, which were of equal gross energy and protein content but differed in fat composition. The high medium-chain triglyceride (MCT) formula contained medium- and long-chain triglycerides in a weight/weight ratio of 46:54; in the low MCT formula the ratio was 4:96. The hypothesis tested was that under conditions of equal gross energy intake the two diets would differ in their digestible and metabolizable energy contents and would produce differences in the infants' rates of energy expenditure and energy storage. Gross energy intakes averaged 562 and 555 kJ/kg/day (134 and 133 kcal/kg/day) with the high and low MCT formulas, respectively. With each diet, coefficients of energy digestibility (0.93) and metabolizability (0.91) were identical; the rates of energy expenditure were 262 (high MCT) and 265 (low MCT) kJ/kg/day (63 kcal/kg/day for both diets), and of energy storage were 246 (high MCT) and 239 (low MCT) kJ/kg/day (59 and 57 kcal/day). These differences were not significant. There were also no significant differences between the two diets in coefficients of nitrogen retention (mean 0.70) or in rate of weight gain (mean 21.5 gm/kg/day). The use of high MCT content in infant formula neither provided a nutritional advantage in energy digestibility or metabolizability nor resulted in an increased rate of energy expenditure or of energy storage.

Body Weight↗
PubMed1985

Energy intake and the nature of growth in low birth weight infants.

Growth is accompanied by and depends on energy storage in growing tissue. The rate of energy storage in growing low birth weight infants depends on the rate of energy intake and on the rates of energy excretion and expenditure, both of which (on a body weight basis) are much higher than in adults, and both of which increase with increments of gross energy intake. Energy-balance studies of growing low birth weight infants on gross energy intakes approximating 500 kJ X kg-1 X d-1 of mothers' milk or of infant formula indicate that the composition of extrauterine weight gain of the low birth weight infant differs from that of the fetus of similar gestation, in that the energy storage cost of growth is much higher. Attempts to increase metabolizable energy intake beyond 500 kJ X kg-1 X d-1 by energy supplementation alone do not result in proportionately increased rates of weight gain; low birth weight formulae, in which energy, protein, and mineral contents are all increased can result in large weight gains with proportionate increases in rates of protein and fat accretion.

Body Temperature↗
PubMed1985

Association between indicators of perinatal asphyxia and adverse outcome in the term infant: a methodological review.

There are conflicting opinions about the significance of 5 perinatal findings felt to be indicators of asphyxia (meconium staining of the amniotic fluid, abnormal fetal heart rate patterns, acidotic fetal scalp blood gases, low Apgar scores, and acidotic cord blood gases). A review of the literature was undertaken to determine the strength of association of each of these findings with adverse outcomes. Although all studies contained methodological problems, these indicators were found to have strong associations with one or more adverse outcomes such as perinatal death, low Apgar scores or cerebral palsy. The strength of the association (relative risk) was found to vary inversely with the prevalence of the outcome.

Acidosis↗
PubMed1984

Determinants of size at birth in a Canadian population.

Anthropometric, medical, and sociodemographic characteristics and smoking habit of a random sample of postpartum women in a Canadian population were determined. These characteristics were analyzed in relation to the birth size of their babies. With controls for gestational age and fetal sex, the following maternal variables were positively correlated with birth weight: prepregnant weight, weight gain in pregnancy, stature, bicristal and biacromial diameter, calf and upper arm circumference, and triceps and subscapular skinfold thickness. Smoking during pregnancy reduced birth weight by 13 gm per cigarette smoked daily. Similar associations of maternal size and smoking habit were observed with respect to infant length, head circumference, and chest circumference. The predictors of birth weight are proposed for use in adjusting upward or downward the population distribution of birth weight to reflect the individual characteristics of the mother.

Adrenal Cortex Hormones↗
PubMed1984

Size-at-birth standards for an urban Canadian population.

By random sampling of all births occurring in Hamilton, Ont. over an 18-month period the percentile distributions of the newborn infants' weight, length, and head and chest circumferences were determined. The resulting standards may be used in the clinical evaluation of size for gestational age. The smoothed 50th percentile values for newborns of 40 weeks gestational age were as follows for boys and girls respectively: birth weight 3530 and 3355 g, crown-heel length 52.0 and 51.3 cm, head circumference 35.2 and 34.4 cm, and chest circumference 33.4 and 32.8 cm. The mother's height averaged 160.8 +/- 6.1 cm and her weight before the pregnancy 59.2 +/- 10.5 kg. The prevalence of cigarette smoking during pregnancy was 34.8%.

Birth Weight↗
PubMed1984

Outcome in infants 501 to 1000 gm birth weight delivered to residents of the McMaster Health Region.

The mortality and morbidity for all 255 live births of infants with birth weight 501 to 1000 gm and delivered to residents of a geographically defined region between 1977 and 1980 are reported. In all, 117 (46%) infants were discharged alive; there were four postdischarge deaths, and three infants were lost to follow-up. The mean birth weight and gestational age of the survivors was 850 +/- 118 gm and 27.1 +/- 2 weeks, respectively. Neurosensory handicaps were detected in 26 (24%) of 110 survivors followed for a minimum of 2 years corrected age. In addition, 29 (26%) infants had nonneurologic problems and 55 (50%) were considered apparently normal. Within 100 gm birth weight groups, survival improved significantly with increasing birth weight, but the handicap rate among survivors remained relatively constant. These figures are proposed for use in describing the current prognosis at birth for liveborn tiny infants from comparable unselected populations.

Anthropometry↗
PubMed1983

Economic evaluation of neonatal intensive care of very-low-birth-weight infants.

We evaluated the economic aspects of neonatal intensive care of very-low-birth-weight infants, using outcomes and costs of care before and after the introduction of a regional neonatal-intensive-care program. Neonatal intensive care increased both survival rates and costs. For newborns weighing 1000 to 1499 g, the cost (in 1978 Canadian dollars) was $59,500 per additional survivor, $2,900 per life-year gained, and $3,200 per quality-adjusted life-year gained; intensive care resulted in a net economic gain when figures were undiscounted but a net economic loss when future costs, effects, and earnings were discounted at 5 per cent per annum. For infants weighing 500 to 999 g, the corresponding costs were $102,500 per additional survivor, $9,300 per life-year gained, and $22,400 per quality-adjusted life-year gained; intensive care resulted in a net economic loss. By every measure of economic evaluation, the impact of neonatal intensive care was more favorable among infants weighing 1000 to 1499 g than among those weighing 500 to 999 g. A judgment concerning the relative economic value of neonatal intensive care of very-low-birth-weight infants requires a comparison with other health programs.

Adolescent↗
PubMed1983

Regional cerebral glucose metabolism of newborn infants measured by positron emission tomography.

The new diagnostic technique, positron emission tomography with 18F-2-fluoro-2-deoxy-D-glucose (18FDG), was used to measure regional cerebral glucose metabolism in five newborn infants with demonstrated structural abnormalities of the brain. 18FDG was synthesized, diluted in normal saline and injected intravenously. After one hour, tomographic slices of the brain were obtained, the level of the slices being defined relative to the cerebral ventricles. Glucose metabolism of grey- and white-matter structures in the brain could be differentiated clearly. Decreased glucose metabolism was identified in regions of the brain shown by computerized axial tomography to be structurally abnormal. Positron emission tomography is a promising new diagnostic tool for the study of newborn infants with suspected abnormalities of brain function.

Brain↗
PubMed1983

Energy balance and nitrogen balance in growing low birthweight infants fed human milk or formula.

Energy and nitrogen balances were measured in growing low birthweight infants fed either mother's expressed breast milk or a 20 kcal per ounce formula to determine whether or not there were differences between the two dietary groups in (1) the partition of energy among excretion, expenditure, and storage and (2) the relation of energy storage and nitrogen retention to weight gain. There were no significant differences between the human milk fed infants and formula fed infants in gross energy intake, metabolizable energy intake, nitrogen intake, or nitrogen retention. Energy expenditure was significantly lower in the human milk fed infants than in formula fed infants (221 kJ/(kg. day) and 244 kJ/(kg. day), respectively). There was no difference in mean energy storage between the two groups. Although weight gains were similar in both dietary groups, the ratio of energy storage to weight gain was significantly greater in infants fed with human milk (15.3 kJ/g, S.D. 2.0) than in infants fed formula (13.2 kJ/g S.D. 1.8). There was no significant difference between the two groups in the ratio of nitrogen stored to weight gain.

Body Weight↗
PubMed1982

Effectiveness of intensive care of very low birth-weight infants.

Perinatal/neonatal intensive care can be evaluated in terms of its efficacy, effectiveness and efficiency. There is good experimental evidence from randomized controlled clinical trials that intensive-care interventions in the perinatal period are efficacious in reducing perinatal/neonatal mortality and fetal/neonatal morbidity. The effectiveness of intensive care programs in large populations has not been tested experimentally. However, population surveys show that perinatal/neonatal mortality is declining and it is likely that this is due in large part to improved perinatal care. Moreover, low birth-weight infants born in Level 3 hospitals have a lower neonatal mortality rate than LBW infants born in hospitals that are less well staffed and equipped. The true size of the reduction in fetal/neonatal mortality that is attributable to perinatal interventions is difficult to estimate from the experience of referral hospitals because of selection bias (both postnatal and prenatal). Thus, the size of the reduction in mortality resulting from the intensive care of VLBW infants is quite striking in hospital-based studies, but more modest in area-based studies. The efficiency of perinatal interventions in reducing death and disability takes into consideration both the health outcomes and the costs attributable to perinatal intensive care. Although neonatal intensive care saves lives, it is doubtful that the rate of handicap in very low birth-weight infants has been much affected. The immediate and long-term costs of neonatal intensive care are high, but a systematic economic evaluation has not yet been published.

Persons with Disabilities↗
PubMed1982

Insensible water loss in newborn infants.

In this review we have described, in some detail, the physical processes involved in water loss from both the skin and lungs. Although at first glance these physical processes may seem complex and confusing, once the basic concepts are grasped, the effect of the many variables in both the babies and their environment on IWL can be seen more clearly. Measurement of IWL, or its components, TEWL and RWL, is difficult in newborn infants. Some of the difficulties arise because of the nature of the subject being studied, and because of inaccuracy in the measuring apparatus. The difficulties in the subjects include lack of cooperation, and the presence of severe illness, both of which may limit the representativeness of any sample of babies that is eventually studied successfully. The size of the subjects studied means that small amounts of water are given off in any fixed period of time. Consequently, the accuracy of the measuring instruments has to be high. As we have discussed, each of the methods used to estimate IWL, TEWL, or RWL has limitations and potential inaccuracies. Despite the difficulties in obtaining estimates of IWL in newborn infants, there have been many studies over the years that have provided clinically useful data. More recently, improved survival of VLBW infants has lead to an awareness that IWL is substantially increased in these tiny babies. The best way to manage the problems of water and heat balance associated with increased IWL in VLBW infants remains to be determined.

Adult↗
PubMed1982

Mortality and morbidity of 500- to 1,499-gram birth weight infants live-born to residents of a defined geographic region before and after neonatal intensive care.

All very low-birth-weight infants live-born to residents of an urban southern Ontario county were studied before (1964 to 1969) and after (1973 to 1977) the introduction of neonatal intensive care. Mortality at hospital discharge decreased from 89.4% to 77.6% among infants whose birth weights were 500 to 999 gm and from 37.6% to 22.8% among infants with birth weights of 1,000 to 1,499 gm. The families of 121/150 (81%) and 134/151 (89%) of all children from the two cohorts who were discharged from the hospital alive were surveyed. At follow-up 7/121 (6%) and 4/134 (4%) had died. Major damage was reported for 13/121 (11%) and 18/134 (13%) of the children. Neonatal intensive care was associated with a significant reduction in mortality but there has not been a significant change in morbidity.

Adolescent↗
PubMed1982

Results of long-term prospective study of the hepatitis B surface antigen (HBsAg) carrier state.

In a prospective study of 180 HBsAg carriers, excluding patients from renal units or active drug users, excluding were followed by up to 8 years (mean 4 years). Four became HGsAg negative. SGPT was normal throughout in 70.6%. The rest had either intermittent, persistent or occasional elevations. The commonest pattern of SGPT abnormally was the intermittent one lasting weeks or months. Serial liver biopsies in carriers with normal SGPT showed mainly lobular infiltrates which reverted to normal. In carriers with elevated SGPT, portal infiltrates were found which persisted, compatible with a clinico-pathologic diagnosis of chronic persisting hepatitis (CPH). One patient progressed to liver cirrhosis and one developed CAH and cirrhosis. No patient developed hepatocellular carcinoma. HBsAg carriers can be divided into 2 groups: a) healthy, b) with asymptomatic chronic hepatitis B. Liver biopsy is recommended in group b, but not in group a.

Adult↗
PubMed1982

Energy cost of growth of premature infants.

The objective of this paper is to review approaches to the determination of the energy cost of growth in premature infants. Two approaches are compared: one based on the composition of weight gain, and one based on the determination of energy balance. Data are lacking on the composition of weight gained by the premature infant after birth, while the composition of fetal weight gain and its energy cost can be calculated from data on fetal body composition. These calculations show that energy storage amounts to less than 8.4 kJ/g weight gain below a body weight of 2 kg; the total energy cost of growth is less than 10.5 kJ/g. Estimates twice as high have been obtained from energy balance studies of growing premature infants and older infants. We conclude that the energy cost of growth in premature infants is still uncertain and requires further study.

Body Composition↗