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Biomedical subjects

G G Harrison

Publications and source records attributed to G G Harrison.

At least 37 records · Page 2Linked to original sources
PubMed1994

Onset and evolution of stunting in infants and children. Examples from the Human Nutrition Collaborative Research Support Program. Kenya and Egypt studies.

The etiology of the early onset of stunting is diverse among populations of varying biological, environmental and cultural circumstances. This is exemplified within the Nutrition CRSP project, which took place in three different populations and ecological conditions. Within each study area a different mix and varying proportions of causative factors were identified. At least in Kenya, and probably in Mexico, the problem has its antecedents in prepregnancy and pregnancy. Powerful determinants of the infants' size at birth and during the first 6 months of life are maternal size upon entry into pregnancy, and weight and fat gain during pregnancy and lactation. In all three countries a low pregnancy weight gain was observed. Notably in Kenya, where the energy intake of the mother decreases progressively throughout pregnancy, not only do mothers gain only half as much as European or North American women, but they even lose weight and fat in the last month of pregnancy, and some mothers gain no weight or lose weight during the whole of pregnancy. Mothers in Kenya start lactation with relatively poor fat stores. Although their energy intake increases somewhat during lactation, preliminary estimates suggest that these increases may be insufficient to maintain their bodily integrity, to carry out their normal tasks of daily living, and to produce a sufficient amount of milk for optimal infant growth. In addition to an energy deficit, diet quality is a problem, particularly in Kenya and Mexico and less so in Egypt. Intakes of animal products and animal protein are very low. Zinc and iron intakes are not only low, but the bioavailability of these nutrients is poor because of the high phytate, fiber and tea content of the diet. Also vitamin B12 intake is extremely low, and at least mild-to-moderate iodine deficiency (IDD) is present in Kenya. The above micronutrients have been demonstrated to affect the linear growth of the Kenyan children, even after confounding factors have been controlled. The early use of supplemental feeding in Kenya is a double-edged sword. On the one hand, there is a slight increase in febrile illness and possible displacement of breast milk intake in the supplemented infants, although mothers do not decrease breast feeding frequency and duration. On the other hand, even the modest amounts of available zinc and B12 in supplemental foods appear to have a positive effect on linear growth.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1993

Breastfeeding and weaning in a poor urban neighborhood in Cairo, Egypt: maternal beliefs and perceptions.

Maternal beliefs and perceptions about breastfeeding and weaning were investigated in a series of in-depth, open-ended interviews with 20 mothers of infants aged 2-12 months in a poor neighborhood of metropolitan Cairo during July-September 1990. The traditional pattern of breastfeeding well into or through the second year of life is changing rapidly, although essentially all mothers still wish to breastfeed and do so at least initially. Beliefs and behaviors reported varied somewhat by rural/urban origins of the mother herself, but exhibited consensus on many issues. The ability to breastfeed successfully is perceived to be a blessing, and to require maturity, patience and a sense of responsibility. The quantity and quality of breast milk are believed to be influenced by a wide variety of factors including the childs age and individual characteristics, the psychological and physical state of the mother, and her diet. Mothers reported a number of behaviors that are perceived to influence the quality of breast milk including changes in their diet when the infant was ill and behaviors designed to optimize the humoral qualities (hot/cold, light/heavy) of the milk. Supplementation with sugar water beings very early, and gradual introduction of other foods generally is begun soon after 40 days of age. Mixed formula and breastfeeding is commonly perceived to increase the nutritional quality of the childs diet. Weaning is ideally related to developmental milestones (walking, complete dentition) but often occurs early due to a variety of factors including maternal illness, desire for another pregnancy, and perceptions that breast milk may be inadequate. Weaning is perceived to be a difficult and dangerous transition.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Diet during lactation associated with infant behavior and caregiver-infant interaction in a semirural Egyptian village.

Potential processes through which nutritional and non-nutritional factors can relate to infant state and behavior and mother-infant interactions were examined in 41 mother-infant pairs from semirural Egyptian households. All infants were breast-fed, and breast milk was the main source of their nutrient intake. Median birth weight was close to reference median; however, most infants showed growth faltering when they were 3-6 mo of age. Among the infant behavioral and state variables, only drowsiness (a proxy for activity and alertness) was significantly associated with the nutritional and non-nutritional factors examined. Among these factors, mothers' intakes of animal source foods and certain B vitamins were the strongest predictors of drowsiness. The nature of the association between maternal diet and drowsiness, examined by multiple regression analysis, showed clearly that inadequate diet of the mother was the major risk factor. Alertness of infants was further compromised when there were several children in the households. The small, less vocal and less alert infants received less vocalization from their mothers. In this environment, infants of undernourished mothers may not receive the extra care and stimulation needed and are at risk for subsequent developmental disabilities.

Behavior↗
PubMed1992

Method for the safe and rapid pretransfusion warming of stored blood: an in vitro and in vivo evaluation of a radiofrequency (RF) instrument.

Inadvertent hypothermia due to massive infusion of stored blood can be prevented by pretransfusion warming. One approach is the heating of individual packs by means of electromagnetic conduction, which is a method safely used over the last 25 years. The prototype instrument, which has now been re-engineered, can effectively raise the temperature of a unit of blood to approximately 33 degrees C in less than 3 minutes. Using this new model, we found, in vitro, a modest increase in free plasma haemoglobin, but this was not accompanied by any change in potassium or lactic dehydrogenase levels and the mean red cell fragility was unaltered. In vivo, the survival of autologous red cells that had been stored for 33 days and then infused as a concentrate, having a mean haematocrit of 0.60, was measured at 24 hours and 21 days. Each donor acted as his own control. In paired studies, pretransfusion radiofrequency heating was shown to have no deleterious effect when compared to measurements using the unwarmed blood pack. It is concluded that this method can be recommended as safe.

Adult↗
PubMed1992

Malignant hyperthermia. An historical vignette.

This paper reports previously unpublished accounts of the deaths in 1915 and 1919 of two members of the same family during general anaesthesia. The deaths were subsequently ascribed to a 'hereditary susceptibility' to chloroform. Contemporary evidence is presented which suggests that these deaths were among the very earliest examples of malignant hyperthermia to be described.

Child, Preschool↗
PubMed1991

Plasma response to oral beta-carotene in Guatemalan schoolchildren.

The response to oral doses of beta-carotene (0 mg, n = 10; 15 mg, n = 20; and 30 mg, n = 21) was studied in 51 Guatemalan children aged 8-15 y, with mean fasting plasma retinol concentrations of 1.72 +/- 0.38 mumol/L. Beta-carotene was delivered with a chocolate drink containing 8.4 g fat. Serial blood sampling was performed at intervals up to 48 h. Circulating retinol concentrations remained relatively constant. The maximum increases in plasma beta-carotene after the 30- and 15-mg doses for all subjects occurred at 24 h and were 0.29 and 0.23 mumol/L, respectively. Time of maximum increase for individuals varied and average maxima over the 48-h period for individuals were 0.13 and 0.26 mumol/L for the 15- and 30-mg-treatment groups, respectively. Increased plasma beta-carotene concentrations were not predicted by recent intake of dietary vitamin A, fasting plasma concentrations, or anthropometric measurements.

Administration, Oral↗
PubMed1991

Determinants of pregnancy outcome and newborn behavior of a semirural Egyptian population.

Several potential determinants of birth weight and neonatal behavioral organization, ie, maternal anthropometry, food intake (energy, protein, and plant- and animal-source foods), morbidity, and household socioeconomic status, were followed systematically in a semirural Egyptian population during greater than or equal to 6 mo of pregnancy. In early pregnancy mothers were generally normal weight to moderately overweight. Their mean energy intake, largely from plant sources, was approximately 8.37 MJ/d (2000 kcal/d) during trimesters 2 and 3. Early (3 mo) pregnancy weight and weight gain during trimesters 2 and 3 were significantly positively related to birth weight Z scores. The best predictor model examined for birth weight included early pregnancy weight, weight gain, and length of gestation (R2 = 0.45). Early pregnancy weight and maternal intake of animal-source foods were significant positive predictors of the newborn's orientation and habituation behavior, respectively. Habituation and orientation measures assess the infant's early ability to process information.

Adult↗
PubMed1991

Propofol as an i.v. anaesthetic induction agent in variegate porphyria.

The choice of an i.v. anaesthetic induction poses problems for the anaesthetist confronted with a patient with one of the acute porphyrias. We undertook a prospective clinical trial in 13 variegate porphyric subjects using propofol as an anaesthetic induction agent. Urinary porphyrin precursors and porphyrins were measured before operation and 1-5 days after operation. Stool and plasma porphyrin concentrations were measured over the same period. Comparison of these data in the porphyric patients and in 21 control subjects over the trial period revealed no significant change in porphyrin or porphyrin precursor output after operation. Urinary porphyrin precursor concentrations did not exceed the limits established for variegate porphyric patients in remission, and there were no changes in the stool and plasma porphyrin profiles or any symptoms of an acute porphyric attack. We conclude that propofol did not appear to be porphyrinogenic when used for the induction of anaesthesia in 13 patients with variegate porphyria.

Adolescent↗
PubMed1990

Death due to anaesthesia at Groote Schuur Hospital, Cape Town--1956-1987. Part I. Incidence.

The data from a 30-year surveillance study of anaesthetic mortality associated with 0.75 million anaesthetics administered at Groote Schuur Hospital, Cape Town, from 1956 to 1987 are presented. Behind an overall mortality rate of 0.19 deaths per 1,000 anaesthetics attributable to anaesthesia, lies a 6-fold decrease in the incidence, computed quinquennially, from 0.43 per 1,000 anaesthetics in the first quinquennium to 0.07 per 1,000 anaesthetics in the last. The latter figure portrays a standard of safety in anaesthesia for the patient equal to anywhere in the world.

Anesthesia↗
PubMed1990

Death due to anaesthesia at Groote Schuur Hospital, Cape Town--1956-1987. Part II. Causes and changes in aetiological pattern of anaesthetic-contributory death.

A general analysis of the clinical failures that were responsible for deaths attributable to anaesthesia over a 30-year period, 1956-1987, is presented. Four particular general failures in clinical management were responsible for 80% of anaesthetic-contributory deaths (ACD). These were in descending order of frequency: (i) failures in airway management, of which the majority were associated with the complications of endotracheal intubation (27% of ACD); (ii) failures in pulmonary ventilation management (20% of ACD); (iii) failures in blood volume control (19% of ACD); and (iv) failures in arrhythmia control (17% of ACD). Computation of these groups of causes by the decade reveals a distinct and progressive change in the aetiological pattern of these deaths with time. While the incidence of ACD over the period decreased 6-fold from 0.43 to 0.07/1,000 anaesthetics, that proportion due to failures in airway management, in general, and complications of intubation, in particular, has progressively increased. This has been accompanied by a reciprocal decrease in deaths due to circulatory factors. It is postulated that this change arises from the fact that the physical skills, manual dexterity and clinical judgement demanded by the former have not changed with time, whereas the latter depend on intellectual responses to information derived from ever-improving vital function monitoring.

Anesthesia↗
PubMed1990

Vitamin B-6 status of Egyptian mothers: relation to infant behavior and maternal-infant interactions.

Functional consequences of marginal maternal vitamin B-6 status for behavior of the neonate and for mother-infant interactions at age 3-6 mo were assessed by a double-blind procedure. In 27 of 70 Egyptian village women studied, vitamin B-6 concentration of their milk was considered indicative of poor maternal vitamin B-6 nutriture. Neonatal behavior, quantified by the Brazelton Neonatal Behavioral Assessment Scale, showed that consolability, appropriate build-up to a crying state, and response to aversive stimuli were significantly correlated with maternal vitamin B-6 nutriture. Naturalistic observational procedures, used twice monthly with infants aged 3-6 mo, indicated that mothers assessed as having marginal vitamin B-6 status were less responsive to their infants' vocalizations, showed less effective intervention to infant distress, and were more likely to use older siblings as care-givers than were mothers of better vitamin status. We conclude that vitamin B-6 was a factor influencing both the behavior of the mother and her infant.

Adult↗
PubMed1990

Comparison of methods for estimating body composition in young and elderly women.

Estimates of percent body fat and fat-free mass (FFM) were made in healthy young and elderly female subjects using five different methods: bioelectrical impedance analysis (BIA); regression equations involving skinfold measurements at two (Durnin and Womersley; SKF-DW) or three (Jackson and Pollack; SKF-JP) sites; the body mass index (BMI); and an equation relating height and weight to total body water (TBW). Three of the five methods indicated that the percent body fat was significantly greater in the elderly age group. Similarly, three methods estimated FFM values that were significantly lower in the elderly group. In the young group the SKF-DW and TBW methods produced percent fat estimates significantly higher than the other three methods. In the elderly group the percent fat estimates were as follows: SKF-DW greater than BIA greater than SKF-JP = TBW greater than BMI. FFM estimates in both age groups were in inverse rank order to the percent fat estimates. In elderly subjects SKF-DW produced results closest to those from BIA, whereas in young subjects SKF-JP provided the best agreement with the BIA procedure.

Adipose Tissue↗
PubMed1989

Development and evaluation of a colour-coded scale for birthweight surveillance in rural Egypt.

Birthweight surveillance is an important epidemiologic tool, yet it is largely unattainable in locales where most births occur at home attended by traditional midwives. A tempered-steel hand-held scale developed by Program for Appropriate Technology in Health (PATH, Seattle, USA) was adapted for use by Egyptian traditional midwives; it identified newborns weighing less than 2.5 kg by a colour code (yellow versus blue). The scale and reporting system were field tested in a rural Egyptian village. Traditional midwives reported 98% of 299 livebirths attended and 85% were reweighed by Salter scale within 48 hours. Sensitivity of the scale was 100%, specificity 94%. Field conditions are specified for incorporating this method into a surveillance system.

Adult↗
PubMed1989

The screening of propofol in MHS swine.

This study investigated the use of propofol in swine genetically susceptible to malignant hyperthermia (MH). Thirteen animals were exposed to 2% halothane in inspired air, a propofol infusion of 12 mg.kg-1.hr-1 for up to 45 min, or a combination of both. When MH was triggered the animals were treated with dantrolene. Mean onset time of malignant hyperthermia on exposure to halothane alone was 7.2 min +/- 3.0 min and onset with propofol and halothane was 5.0 +/- 2.5 min. In no instance did propofol alone trigger the syndrome nor was there a statistical difference (P less than 0.05) in onset time when the drug was used in conjunction with halothane. On the basis of these results, we conclude that propofol is almost certainly safe for use in humans who are susceptible to MH.

Anesthetics↗
PubMed1988

Halothane: inhibition and activation of rat hepatic glutathione S-transferases.

Multiple halothane anesthesias (1.25 MAC for 1 hr on 3 alternate days) of male Long-Evans rats initially decreased by up to 30% and subsequently increased to up to 185% liver cytosolic glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene, 3,4-dichloro-1-nitrobenzene and trans-4-phenyl-3-buten-2-one and glutathione peroxidase activity. Halothane rapidly and reversibly activated hepatic cytosolic glutathione S-transferases and purified isoenzyme 1-2 but not isoenzymes 1-1 and 3-3. At high concentrations of halothane (ca. 22 mM), maximal activation was ca. 25%. Halothane, enflurane, isoflurane and methoxyflurane, but not the halothane metabolite 1-chloro-2,2-difluoroethylene, inhibited a mixture of liver cytosolic glutathione S-transferases with time (ca. 30% inhibition/15 min). The inhibition exhibited pseudo-first order kinetics (kobs = 0.13 min-1) and an I50 for halothane of greater than or equal to 15 mM. Halothane inhibited glutathione S-transferases 3-3, 3-4, and 4-4 by 50-60%, but did not affect isoenzymes 1-1 and 1-2. The ability of halothane to diminish hepatic glutathione S-transferase activity in vivo may in part reflect the time-dependent inhibition of glutathione S-transferase isoenzymes containing the 3- and 4-subunits.

Anesthesia↗