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Biomedical subjects

P A Adam

Publications and source records attributed to P A Adam.

At least 19 recordsLinked to original sources
PubMed1996

Pyomyositis revisited.

Pyomyositis, purportedly a common tropical infection affecting mainly healthy adults and children, appears to be most uncommon in this region. We report a case of pyomyositis caused by a Methicillin-resistant Staphylococcus aureus (MRSA) in a previously healthy army officer. This case serves to illustrate the difficulty in recognising this disease entity, which is why many cases may have been missed. With the increasing incidence of MRSA nosocomial infections, the emergence of MRSA in a hitherto community-acquired infection poses a major concern especially since intravenous drug abuse and acquired immune deficiency syndrome (AIDS) are on the rise in our country. We hope to inculcate greater awareness of this infection.

Adult↗
PubMed1981

The effect of enteric galactose on neonatal canine carbohydrate metabolism.

Newborn pups were assigned to a fasting group or to a group receiving intravenous glucose alimentation. Glucose turnover was determined during steady state equilibration of simultaneously infused [6-3H] glucose. Thereafter, pups from each group received 0.625 g/Kg of either oral [U-14C] galactose or [U-14C] glucose. In fasted or intravenously alimented pups enteric glucose resulted in a rapid and sustained elevation of blood glucose concentrations. Systemic appearance of carbon-14 label from enteric glucose increased rapidly as did the enrichment of blood [14C] glucose specific activity. In those pups given enteric galactose, blood glucose values were equivalent to that in the glucose fed groups, however carbon-14 appearing in blood glucose and blood glucose specific activity was significantly lower. The peak values for rates of appearance and disappearance of systemic glucose were significantly lower in pups fed galactose than among pups fed glucose. Glucose clearance was also significantly lower in these pups despite equivalent plasma insulin responses. Among fasting pups hepatic glycogen content was significantly higher in those given either oral glucose or galactose when compared to a completely starved control group. In contrast, among alimented pups galactose administration significantly enhanced hepatic glycogen content compared to those fed glucose. Similarly, enteric substrate label incorporation into hepatic glycogen was enhanced in both groups given oral labeled galactose. In addition, hepatic glycogen synthase (glucose-6-phosphate independent) activity was increased only among alimented pups fed galactose when compared to completely fasted pups. In conclusion these data suggest that following gastrointestinal galactose administration, hepatic carbohydrate uptake is augmented while glycogen synthesis may be enhanced. Augmented glycogen synthesis following galactose administration may reflect alterations in hepatic glycogen synthase activity or enhanced hepatic carbohydrate uptake.

Animals↗
PubMed1981

Fetal and neonatal cerebral metabolism following maternal canine starvation.

Pregnant dogs were starved for 72 hr before a term delivery. Maternal (1.68 +/- 0.39 versus 0.74 +/- 0.20 mM) and fetal (0.39 +/- 0.03 versus 0.22 +/- 0.07) circulating free fatty acids and maternal (2.99 +/- 0.79 versus 1.04 +/- 0.84) and fetal (2.53 +/- 0.35 versus 1.01 +/- 0.32) ketones were elevated whereas blood glucose values remained unchanged at the time of delivery. After birth, pups born to starved mothers had significantly lower blood glucose values during 3, 6, 9, and 24 hours of neonatal fasting. Intracerebral glucose concentrations paralleled those in the blood as they were depressed at 3, 6, and 9 hours of age. Cerebral glycogen content was lower in pups born to starved mothers at 6 (2.72 +/- 0.43 versus 4.32 +/- 0.56 mumoles/g) and 24 (2.31 +/- 0.17 versus 3.48 +/- 0.39 mumoles/g) hr, whereas UDP-glucose concentrations were significantly elevated in these pups during fetal, 3, 9, and 24 hr of age. Phosphoenolpyruvate was higher after maternal starvation in the fetus and at 6 and 9 hr, whereas cerebral pyruvate concentrations were elevated at 3, 6, and 9 hr of age. The elevation of pyruvate with no alteration of lactate concentration resulted in an elevated cytoplasmic NAD/NADH ratio at 3 hr of age (1381 +/- 194 versus 792 +/- 198). Cerebral alpha-ketoglutarate and calculated oxaloacetate concentrations were elevated throughout the day after maternal starvation whereas malate concentrations were depressed at 3 and 9 hr of age. Cerebral energy charge was unaffected, whereas the calculated energy reserve was lower at 3, 6, and 24 hours. Cerebral amino acids demonstrated elevated aspartate concentrations at 3 and 6 hr. Cerebral glutamine concentrations were lower during fetal stage (7.86 +/- 0.52 versus 10.01 +/- 0.41 mumoles/g) and 3, 6, and 9 hr of life.

Adenine Nucleotides↗
PubMed1981

Fetal and neonatal responses to maternal canine starvation: circulating fuels and neonatal glucose production.

Pregnant dogs were starved for 72 hr while controls were fasted overnight. Maternal starvation significantly reduced fetal birth weight (269 +/- 7.2 versus 294 +/- 4.4 g). Total caloric deprivation had no effect on maternal or fetal blood glucose concentration at the time of delivery; however, fasting neonatal blood glucose levels were depressed during the first 9 hr of life. Starvation produced a large elevation of maternal free fatty acids (1.68 +/- 0.39 versus 0.74 +/- 0.2 mM) and ketone bodies (2.99 +/- 0.70 versus 1.04 +/- 0.48). Although fetal free fatty acids increased minimally (0.39 +/- 0.03 versus 0.22 +/- 0.07), ketone body levels were markedly elevated (2.53 +/- 0.35 versus 1.01 +/- 0.32). After birth, plasma-free fatty acid and beta-hydroxybutyrate levels were lower in pups of starved mothers at 3 hr, and acetoacetate was lower at 6 and 9 hr. Other alternate fuels such as amino acids demonstrated lower levels of glutamine in pups of starved mothers throughout the day (except 3 hr), whereas alanine levels declined significantly only at 24 hr (114.9 +/- 15 versus 187.6 +/- 26 microM. Glucose production was significantly depressed in pups of starved mothers at 3 (13.7 +/- 1.4 versus 22.7 +/- 3) and 9 hr (17.5 +/- 2.2 versus 26.0 +/- 2.8 mumoles/kg/min), whereas glucose clearance rates were elevated at 3, 6 and 9 hr of age. Lactate carbon incorporation into glucose increased throughout the day but was not significantly affected by prior maternal starvation.

Amino Acids↗
PubMed1980

Substrate-turnover interrelationships in fasting neonatal dogs.

Substrate-turnover relationships were determined in unanesthetized healthy fasted neonatal dogs during the first day of life. Pups were born at term by cesarean section to starved or control mothers. Pups born to starved mothers developed significantly lower blood glucose concentrations during neonatal fasting. In all pups, blood glucose concentrations during neonatal fasting. In all pups, blood glucose concentrations correlated to glucose utilization (r = 0.462, P < 0.001). Blood lactate concentration was significantly related to its turnover. The relationship between lactate turnover and lactate carbon appearance into glucose was significantly correlated. However, the relationship between lactate concentration and its carbon incorporation into glucose was only significant at 24 h of age in pups born to starved mothers. These data suggest that the neonatal dog is capable of regulating its glucose and lactate utilization by the availability of substrate. Because peripheral insulin levels correlated poorly to fasting blood glucose and glucose turnover; it is doubtful whether insulin secretion plays a significant role in fasting neonatal canine glucose homeostasis.

Animals↗
PubMed1980

Estimation of glucose turnover and 13C recycling in the human newborn by simultaneous [1-13C]glucose and [6,6-1H2]glucose tracers.

To compare two methods of estimating systemic glucose production rates and to quantify carbon tracer recycling, six newborn infants, aged 2 h to 3 days, were infused simultaneously with [1-13C]glucose and [6,6-2H2]glucose tracers. The older infants were studied 6 h after a meal. [1-13C]Glucose was infused at 6 microgram/kg.min. Systemic glucose production rates were calculated from tracer dilution, assuming steady state kinetics. Although 13C was expected to randomize away from the C-1 of glucose, recycling occurred and was estimated from the difference in the rate of systemic glucose production quantified by the dilution of the two tracers. Systemic glucose production rates ranged from 4.2--5.4 mg/kg.min. Recycling on the glucose C-1 was 3--20% of the systemic glucose production rate and did not change with the age of the infant. Because recycling of glucose carbon signifies gluconeogenesis from lactate or pyruvate, it is concluded that the human newborn is able to initiate gluconeogenesis soon after birth.

Blood Glucose↗
PubMed1979

Glucose production in pregnant women at term gestation. Sources of glucose for human fetus.

The effects of pregnancy and diabetes on systemic glucose production rates and the sources of glucose for the human fetus in utero were evaluated in five normal, four gestationally diabetic, and one insulin-dependent diabetic subject undergoing elective caesarean section at term gestation. Five normal nonpregnant women were studied for comparison. Systemic glucose production rates were measured with stable tracer [1-(13)C]glucose according to the prime-constant rate infusion technique. Even though the plasma glucose concentration during normal pregnancy had declined as compared with the nonpregnant subjects (P < 0.0005), the systemic glucose production rate was 16% greater, a rate sufficient to provide the glucose requirement of the fetus at term gestation. The decline in glucose concentration could be the result of an increase in apparent volume of distribution of glucose. Systemic glucose production rates in well-controlled, gestationally diabetic subjects were similar to those in normal pregnant subjects (2.07+/-0.53 vs. 2.42+/-0.51 mg/kg.min). The sources of glucose for the human fetus at term gestation were evaluated by comparing (a) natural variation in (13)C:(12)C ratio of plasma glucose and (b) enriched (13)C:(12)C ratio of plasma glucose during [1-(13)C]glucose infusion in maternal and fetal blood at delivery in both normal and diabetic subjects. These data showed that the fetal glucose pool was in equilibrium with the maternal glucose pool in both normal and diabetic subjects, indicating that a brief maternal fast did not initiate systemic glucose production in human fetus. A materno-fetal gradient was observed for betahydroxybutyrate.

Adolescent↗
PubMed1977

Lack of gastrointestinal enhancement of the insulin response to glucose in newborn infants.

Forty-five normal newborn infants were infused with glucose at constant rates by intravenous or nasogastric routes. Blood glucose rose to higher levels during IV than during NG infusions at identical rates; however, the glycemic responses were similar when NG glucose infusions at 12 mg/minute/kg were compared with IV infusions at 6 mg/minute/kg. The plasma insulin responses to glucose were not enhanced by NG administration. Thus, enterohormonal responses to glucose may not affect pancreatic beta cell regulation of glucose assimilation in the newborn period.

Administration, Oral↗
PubMed1977

Estimation of glucose turnover with stable tracer glucose-1-13C.

Glucose turnover was measured in normal and disbetic dogs by the dilution of glucose-1-13C and glucose-1-14C tracers infused simultaneously at constant rates. In order to quantify the stable isotope, an enzymatic assay for the analysis of glucose-1-13C was developed and evaluated. CO2 from C-1 glucose was evolved by coupling hexokinase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconic dehydrogenase activities. The 13C/12C ratio of the CO2 was measured with a high-precision magnetic-deflection double-collector mass spectrometer, and the radioactivity of 14CO2 was quantified by liquid scintillation. The ratio of 13C/12C was reproducible in assays of CO2 evolved from either naturally occurring or 13C-enriched glucose. Furthermore, systemic glucose production rates measured with 13C- and 14C-labeled tracers were similar over a wide range from 2 to 12 mg./kg.-min. Thus, glucose-1-13C may be employed as a tracer for glucose metabolism in human subjects without incurring the risk of radiation.

Animals↗
PubMed1976

Measurement of glucose turnover in the human newborn with glucose-1-13C.

Systemic glucose production rates were measured in 6 normal newborn infants by dilution of glucose-1-13C tracer according to the prime constant-rate infusion technique. Glucose production rates were 4.4 +/- 0.39 mg/kg. min. (Mean +/- S.D.) in 4 infants at 2 hours of age, and were 3.83 and 3.86 mg/kg. min. in 2 infants at 1 day of age. Systemic glucose production accounts for 50% of the substrate utilized for oxidative metabolism in newborn infants.

Blood Glucose↗
PubMed1975

Oxidation of glucose and D-B-OH-butyrate by the early human fetal brain.

The isolated brains of 12 previable human fetuses obtained at 12 to 21 weeks' gestation, were perfused through the interval carotid artery with glucose (3 mM) and/or DL-B-OH-butyrate (DL-BOHB), 4.5 MM, plus tracer quantities of either glucose-6-14C (G6-14C) or beta-OH-butyrate-3-14C (BOHB3-14C). Oxidative metabolism was demonstrated by serial collection of gaseous 14CO2 from the closed perfusion system, and from the recirculating medium. Glucose and BOHB were utilized at physiological rates as indicated (mean plus or minus SEM): G6-14C at 0.10 plus or minus 0.01 mumoles/min g brain (n equal 7) or 17.5 plus or minus 1.9 mumoles/min kg fetus; and BOHB3-14C at 0.16 plus or minus 0.05 mumoles/min g (n equal to 5) or 27.3 plus or minus 7.4 mumoles/min kg. Based on fetal weight, glucose metabolism by brain apparently accounted for about 1/3 of basal glucose utilization in the fetus. On a molar basis BOHB3-14C was taken up at 1.47 times the rate of G6-14C. Both BOHB3-14C and G6 14C were converted to 14CO2. The rate of BOHB3-14C conversion to 14CO2 was equal to its rate of consumption, and exceeded the conversion of glucose to CO2 because 45% of the G6-14C was incorporated into lactate-14C. Accordingly, both substrates support oxidative metabolism by brain; and BOHB is a major potential alternate fuel which can replace glucose early in human development.

Blood Glucose↗
PubMed1975

Glucose production in the newborn dog. I. Effects of glucagon in vivo.

Systemic glucose production rates were evaluated 4 hr after feeding in 14 newborn beagle dogs at ages between 1 and 5 days. After a prime injection of radioisotopic tracers, glucose production was determined during infusion of intermixed tracer [2-3H] glucose and [1-14C] glucose at a constant rate. Seven of the new born dogs served as controls throughout the 3-hr period of infusion, while seven of their littermates, infused simultaneously, received glucagon at a constant rate of 3.3 mug/min between 90 and 180 min of study. In control dogs, mean glucose production, determined by dilution of [2-3H] glucose, was 55 +/- 3 mumol/min-kg body weight. During the control period, their littermates produced glucose at a similar rate; however, glucagon infusion raised glucose production to 81 +/- 4 mumol/min-kg. The average glucose production rate estimated with [1-14C]glucose was 88% of that with 3H tracer during the initial control period and 77% during the glucagon injusion. In order to confirm that this discrepancy reflected the recycling of 14C and the early development of gluconeogenesis, and additional 14 new born dogs were infused with potential substrates for [14C] glucose. In separate studies, [U-14C] lactate, [3-14C] lactate, [U-14C] alanine, and [6-14C]- glucose were incorporated into glucose and [1-14C] glucose. Quantification of gluconeogenesis by simultaneous infusion of [6-3H] glucose and [3-14C] lactate in a 5-day-old dog demonstrated that 25% of the glucose produced originated from lactate, whereas 10% was incorporated into carbon 1. Thus, systemic glucose production was established rapidly in newborn dogs and responded to stimulation with glucagon. A significant proportion of the glucose originated from recycling via the gluconeogenic pathway.

Animals↗
PubMed1975

Glucose production in the newborn dog. II. Evaluation of autonomic and enzymatic control in the isolated perfused canine liver.

The effects of birth and morepinephrine on hepatic glucose production, glycogenolysis, and gluconeogenesis were examined in livers isolated from fetal dogs at term, littermates 3 hr after delivery, and newborn dogs 1-5 days old. Livers were perfused in pairs with medium containing (6-3H)glucose (6 mM) and (3-14C)lactate (10 mM +/- a pharmacologic amount of norepinephrine (10(-6)M). Changes in glucose production rates were correlated with changes in the enzymatic activities controlling gluconeogenesis. Net glucose production was less than 0.48 mumol/min-g liver both fetal and 3 hr liver but stablized above 1 mumol/min-g later during the first day. Initially, mobilization of the fetal hepatic glycogen accounted for glucose output. Subsequently, incorporation of lactate into glucose rose from negligible fetal rates to 0.19 mumol/min-g and accounted for 21% of net glucose production on day 3. Mazimal pyruvate carboxylase activity and mitochondrial CO2 fixation increased postnatally and correlated directly with net glucose production, glucose production from glycogen, and glucose production from lactate. Fetal liver did not respond to norepinephrine. Thereafter, norepinephrine increase hepatic glucose production by stimulating glycogen breakdown. Postnatal acceleration of glucose production and the response to norepinephrine occurred only after indiction of mitochondrial CO3 fixation. During day 1 the decline of hepatic glycogen in response to norepinephrine correlated with both CO2 fixation and lactate incorporation into glucose. Thus, initiation of gluconegenesis after birth may have been required for the postnatal acceration of hepatic glucose production and for the regulation of glycogenolysis by norpinephrine.

Animals↗
PubMed1975

Inhibitory effect of prednisone on insulin secretion in man: model for duplication of blood glucose concentration.

Treatment with oral prednisone (15 mg every 6 h) for 1 day plus a 4-h glucose infusion at 2.8 mg/min kg body weight to 5 normal, healthy individuals raised their blood glucose to 137 +/- 4.5 mg per 100 ml (mean +/- SEM). In order to evaluate the effects of steroid-induced hyperglycemia on insulin responses, a model for the duplication of blood glucose concentration in serial studies was developed. During glucose infusion at 5.7 mg/min kg body weight, the fractional uptake of glucose at the end of infusion (KG) was 2.08 +/- 0.2%/min and the apparent volume of distribution (V) was 285 +/- 10.5 ml/kg. Further increase in the rate of glucose infusion did not affect KG and V. Based on these parameters, KG and V, the stable blood glucose achieved during the prednisone study (C) was duplicated both after short (4 h) and prolonged (28 h) glucose infusions (138 +/- 4.5 and 146 +/- 4.5 mg/100 ml, respectively) at rates calculated as the product of KG.C.V. The effects of prednisone treatment on insulin secretion were examined (1) during fasting, (2) at identical glucose concentrations during glucose infusions at constant rates, and (3) in response to glucose pulse (0.1 g/kg) during the infusions. During fasting, there was a significant elevation of mean blood glucose with prednisone (99 +/- 1.8 mg/100 ml) compared with that in the control study (88 +/- 1.7 mg/100 ml). The plasma IRI, however, remained unchanged (10 +/- 2.3 vs 10 +/- 1.6 muU/ml). During glucose infusions in the presence of similar blood glucose levels, the IRI was lower after prednisone treatment (18 +/- 1.5 muU/ml) than during the short and prolonged glucose infusions (42 +/- 5.1 and 63 +/- 7.0 muU/ml). The insulin response to the glucose pulse also was significantly lower during steroid treatment. Thus, prednisone apparently has an early inhibitory effect on the insulin response to glucose.

Blood Glucose↗