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A sensitive and nondestructive radiometric method has been applied to the detection of metabolism of Mycobacterium lepraemurium, as a model for the study of the metabolism and substrate requirements of M. leprae. The method is based on the measurement of the (14)CO(2) produced through the bacterial conversion of [U-(14)C]acetate or [U-(14)C]glycerol by 7 x 10(9) bacteria suspended in 10 ml of either a simple buffer system (K-36) or a complex medium (NC-5). Metabolism of the bacilli was easily detected within 3 days after inoculation and was measured daily. NC-5 medium supported metabolism of M. lepraemurium for several weeks longer than the simple K-36 buffer. The radiometric technique shows promise as a rapid and efficient system for evaluating the metabolism of mycobacteria without introducing any changes in the physiologic state of the organisms, studying their metabolic pathways, determining conditions potentially favorable for multiplication of these organisms in vitro, and studying their susceptibility to inhibition by drugs.

Both transport delay (DELAY) and dynamic response (RESPONSE) of a mass spectrometer would theoretically result in considerable errors in the breath-by-breath calculation of VCO2 and VO2. However, curiously, the contribution of RESPONSE has been ignored. The purpose of this study is to quantify the error caused by RESPONSE. We found that RESPONSE of a mass spectrometer was regarded as a first-order response. We determined DELAY and time constant (T) of RESPONSE and compensated the on-line calculation for both DELAY and RESPONSE and for DELAY only. With T of 150 and 100 ms, deviations of VCO2 from the gas-collection method were 8 +/- 6 and 8 +/- 6 ml/min with compensation for both DELAY and RESPONSE, and 69 +/- 10 and 50 +/- 5 ml/min with compensation for DELAY only, respectively (mean +/- SD). Similar results were obtained with VO2. A computer simulation of error caused by RESPONSE disclosed that the error linearly increased with increasing T. We conclude that to be accurate within +/- 5% of the exact value, compensation should be made when T exceeds 25 ms.

The processes concerned with the production and loss of body heat in sodium salicylate or acetylsalicylic acid antipyresis were investigated in adult rabbits at an ambient temperature of 21.5 +/- 0.5 degrees C. The experimental fever elicited by i.v. injection of lipopolysaccharide Escherichia coli (1 microgram/kg) was accompanied by increases in O2 consumption and CO2 production as well as decreases in convective heat loss. Pretreatment with 200 mg/kg of sodium salicylate (an hour's i.v. infusion) or with the same dose of acetylsalicylic acid (per os) significantly reduced pyrogen fever but the magnitude of O2 consumption and CO2 production remained at least at the febrile level. In the case of sodium salicylate, the level was even exceeded. At the same time both salicylates activated heat dissipation as manifested by decreases in vasomotor tone and tachypnea. Thus, it is apparent that the antipyretic effect of salicylates may develop without the inhibition of heat production. Heat loss processes initiated by these drugs are responsible for the antipyresis.

The acute metabolic response following experimentally induced sepsis can generally be classified as either hypodynamic ("low flow") or hyperdynamic ("high flow"). We have found that in conscious guinea pigs the bolus infusion of 10(10) live Escherichia coli bacteria can elicit either response, depending on the route of administration of the bacteria. Intravenous infusion results in the hypodynamic condition of septic shock in which oxygen consumption (VO2) is reduced to approximately 60% of the control level, plasma glucose is elevated 4 hr after infusion with a reversal to extreme hypoglycemia 12 hr after infusion, and body temperature is reduced by approximately 5 degrees C in 12 hr. In contrast, subcutaneous injection results in increased VO2, body temperature, and plasma glucose. In both models the concentration of cortisol, catecholamines and glucagon were elevated, but the responses were more pronounced in the hypodynamic model. In both cases, insulin concentration was decreased. These models of sepsis are useful because many aspects of response are comparable to man, they are simple to create, and they are consistent and reproducible.

Arginine has been considered as the major energy source of nonglycolytic arginine-utilizing mycoplasmata. When three strains of Mycoplasma arginini, and one strain each of Mycoplasma arthritidis, Mycoplasma fermentans, Mycoplasma gallinarum, Mycoplasma gallisepticum and Mycoplasma hominis were grown in the medium with high arginine concentration (34 mM) compared with low arginine (4 mM), both the protein content of the organisms and the specific activity of arginine deiminase increased. M. fermentans, the one arginine-utilizing species included in the survey which is also glycolytic, showed an increase in protein content but no increase in specific activity of the enzyme. The glycolytic non-arginine-utilizing M. gallisepticum did not show an increase in either parameter. The Km for arginine deiminase from crude cell extracts was 1.66 X 10(-4)M. The enzyme demonstrated a hyperbolic activation curve subject to substrate inhibition and was not affected by the presence of L-histidine. When mycoplasmic protein and arginine deiminase were determined for M. hominis under aerobic and anaerobic conditions, aerobically grown cells exhibited no detectable enzymatic increases until late in log phase. Higher levels of arginine deiminase were observed earlier in the anaerobic growth cycle. The rate of 14CO2 evolution from [guanido-14C]arginine was not altered in arginine-supplemented cells compared with cells grown in low arginine. In addition, CO2 production did not parallel increased arginine deiminase activity. These observations argue that arginine is used only as an alternate energy source in these organisms.

Reactive oxygen species, probably hydroxyl radicals (OH.), have been suggested to be generated during arachidonic acid (AA) metabolism and, once released, these species can modify the rate and extent of various reactions involved in AA metabolism. We have studied this phenomenon in washed human platelets. OH. generation was quantitated using 14C-benzoic acid as a specific trap in a continuous ionization chamber system. Resting platelets did not produce any detectable signal, whereas addition of AA resulted in gradual OH. production with peak values detected at approximately 20 min. Similar studies conducted under nitrogen or after boiling the platelets almost abolished OH. generation. Aspirin had no significant effect, whereas 5,8,11,14-eicosatetraynoic acid decreased the signal by greater than 90%, thus suggesting that OH. is produced primarily through the lipoxygenase pathway. Superoxide dismutase (SOD) and catalase had no effect and, as expected, phenol and mannitol decreased OH. production considerably, by greater than 50% and 90%, respectively. Azide and cyanide also reduced the OH. generation by about two thirds. We conclude that OH. is generated during AA metabolism by human platelets. It is primarily produced via the lipoxygenase pathway and may require a heme-dependent peroxidase. This highly reactive oxidant may play an important role in normal and abnormal hemostasis.

The development of methods for storing platelet concentrates (PCs) at 22 degrees C for transfusion has been predominantly empiric, with minimal knowledge of metabolic events occurring during storage. It is known that a decrease in pH due to accelerated production of lactic acid in hypoxic conditions is a major cause for loss of platelet viability. In the current studies, we have measured metabolic parameters such as O2 and glucose consumption rates and CO2 and lactic acid production rates. We have also determined the O2 and CO2 transport capacities of various containers and the buffering capacity of plasma. The O2 consumption rate was 1.10 +/- 0.16 (SD) nmol/min/10(9) platelets. In well-oxygenated systems, lactic acid formation was 1.74 +/- 0.12 nmol/min/mL PC for PCs with a platelet count of 1 to 2 X 10(9)/mL; and 0.52 mol of glucose was consumed per 1 mol lactic acid produced. In a completely oxygen-free system, lactic acid production increased 5-8-fold. These calculations suggest that 85% of energy generation is derived through oxidative metabolism and that glucose may not be the primary substrate for this metabolism. Bicarbonate concentration, initially 22.1 +/- 1.6 mEq/L, decreased 1.41 +/- 0.18 nEq/min/mL PC for PCs with counts 1 to 2 X 10(9) platelets/mL. The loss of bicarbonate was caused by displacement by lactic acid and as a consequence of spontaneous CO2 efflux from the container. CO2 production, 2.3 +/- 0.4 nmol/min/10(9) platelets, was derived from oxygen consumption and the CO2 liberated from bicarbonate as it was consumed. A rapid fall in pH to levels below 7.0 (22 degrees C) took place when the bicarbonate concentration fell below 5 mEq/L as lactate concentrations reached 20 to 25 mmol/L. A further increase in lactate concentration from 25 mmol/L to 40 mmol/L correlated with a further fall in pH to 5.8. Thus, the ultimate storage life of a PC is determined by continuous lactate production and the fixed buffering capacity of plasma and by the glucose concentration of the PC. With knowledge of these parameters, methods for predicting pH as a function of time, platelet count, and O2 and CO2 transport capability of the container have been developed as guidelines for future work.

The phosphoroclastic system was demonstrated in cell-free extracts of clostridium sporogenes by the production of carbon dioxide, acetyl phosphate, ATP and reduced NAD in the presence of pyruvate. The kinetics of acetyl phosphate production and NAD reduction were investigated. The addition of sodium nitrite to a suspension of C. sporogenes in glucose medium resulted in a rapid decrease in intracellular ATP concentration which was accompanied by an accumulation of pyruvate in the medium. This accumulation of pyruvate was caused by inhibition of phosphoroclastic system by nitrate. Nitrite inhibits this system by reaction of nitric oxide, formed from nitrate, with the non-haem iron of pyruvate:ferredoxin oxidoreductase.

The biodegradability of three aliphatic adipic acid diesters and a 1,3-butylene glycol adipic acid polyester was determined in acclimated, activated sludge systems. Rapid primary biodegradation from 67 to 99+% was observed at 3- and 13-mg/liter feed levels for di-n-hexyl adipate, di(2-ethylhexyl) adipate, and di(heptyl, nonyl) adipate in 24 h. When acclimated, activated sludge microorganisms were employed as the seed for two carbon dioxide evolution procedures, greater than 75% of the theoretical carbon dioxide was evolved for the three diesters and the polyester in a 35-day test period. The essentially complete biodegradation observed in these studies suggests that these esters would not persist when exposed to similar mixed microbial populations in the environment.

Rates of sodium absorption in the presence of bacterial fatty acids and bile salts are unknown along the length of the colon. Such information may guide resection of colon with a view to leaving colon most optimal for ion absorption. Absorption of sodium and permeability of the colonic mucosa to 51Cr EDTA was measured in the proximal (PC) and distal colon (DC) instilled with NaCl (120 mM), n-butyrate (40 mM) and chenodeoxycholic acid (1 or 2 mM) in varying combinations. Sodium absorption in the PC was 123.6 +/- 19 (nmoles/min/cm2)(n = 7) with saline alone and was doubled (P less than .001) when 40 mM n-butyrate replaced chloride anions. Sodium absorption in the DC with saline alone was 106.9 +/- 18 without significant alteration by addition of n-butyrate. CDC (1 mM) diminished sodium absorption in the PC and DC. Diminished sodium absorption induced by bile salts was significantly reversed by n-butyrate in the PC but not DC. Permeability of 51Cr EDTA was greatest with 2 mM CDC in the distal colon. Mucosal function--sodium absorption with SCFAs, permeability changes, and protection by bacterial fatty acids from sodium losses due to bile salts--was superior in the PC compared with DC. Our results suggest that it may be preferable to preserve the proximal rather than distal colon in operations of the colon to secure optimal absorption of sodium.

Large doses of cephaloridine (CER) cause acute necrosis of the proximal renal tubule in various species, as well as gentamicin (GM). However, administration of the two drugs simultaneously resulted in a protective effect of CER against GM related nephrotoxicity in rats. The present studies were designed to examine the mechanism of CER transport system into renal cells in vitro, using the rat kidney slices and 3H-CER, effects of transport system of CER by GM or cephalexin, and effects on CO2 production in rat kidney slices of CER and GM. The results were as follows: 1. CER was transported into cells actively and intracellular concentration of CER became to be equal to extracellular concentration on around 100 mcg/ml of extracellular concentration of CER. 2. GM and CEX inhibited intracellular active transport of CER. 3. CER had inhibitory effect on CO2 production in rat kidney slices and its effect was dose dependent. GM had no effect on CO2 production. The author concluded that intracellular transport system of CER, GM and CEX is the same, and competition may be present, if each drugs are administrated simultaneously. Different attitude on CO2 production of CER and GM does not explain the difference of the mechanism of renal toxicity of each drugs directly. However, it may explain that the mechanism of renal toxicity of CER is not the same as of GM in parts.

Uptake and intracellular transformation of pyrimidines supplying cells of the yeast Rhodotorula glutinis with nitrogen have been studied. The amine nitrogen of cytosine was found to be the easiest to utilize. The presence in the medium of inorganic ammonia along with cytosine had a slight effect on cytosine deaminase (EC 3.5.4.1) activity. The uracil produced entered into the nutrient medium with no fission break of the pyridmidine ring. In the absence of any other source of nitrogen, the cells of the yeast R. glutinis utilized nitrogen of the pyrimidine ring of oxypyrimidines. Catabolism of uracil followed the reductive pattern, with release of carbon dioxide; this was accompanied by synthesis of the key enzyme of pyrimidine catabolism, dihydrouracil dehydrogenase (EC 1.3.1.1), whose activity rose 10-fold. With thymidne as the sole source of nitrogen, the lag-phase growth of the yeast cells was maximum. Catabolism of the pyrimidine ring of thymine was possibly preceded by its transformation into uracil. With no source of nitrogen easily utilized, the uridine 5'-monophosphate content in the generally acid-soluble pool rose. Our discussion of the regulation of catabolism of exogenous pyrimidine bases by the yeast R. glutinis takes into account the fact that transformations of pyrimidine bases are determined by how easily the cells can use a particular base as a source of nitrogen.

An anaerobic population of bacteria became acclimated to catechol and phenol in 32 and 18 days, respectively. Evidence from carbon balance measurements indicates that the aromatic ring is cleaved and that the products are stoichiometrically fermentable to methane and carbon dioxide.

The major growth yield of a prototrophic strain of Bacillus stearothermophilus under aerobic conditions on salts medium containing ammonium nitrate as the nitrogen source and glucose or succinate as the carbon source was maximal at the lowest growth temperature employed and decreased steadily as the temperature was raised. The temperature optima for growth yield and for growth rate were thus different. The molar growth yield values of the thermophile, especially at the lower growth temperatures, were similar to those reported for aerobically grown mesophilic bacteria, both on glucose and on succinate. At the higher growth temperatures, a lower proportion of glucose carbon was incorporated into cells and a correspondingly greater proportion was left incompletely utilized in the medium, mostly as acetate. This suggests a greater inefficiency in the coordination of the nonoxidative and oxidative phases of glucose metabolism at the gigher temperatures. Another factor causing a decreased cell yield at higher temperatures was possibly an uncoupling of energy production from respiration. The rates of respiration by intact cells of the thermophile on glucose and on succinate followed the Arrhenius relationship from 55 C to 20 C, which is some 20 C below the minimal growth temperature of the organism. The Arrhenius constant was 17.1 kcal/mol for glucose oxidation and 13.5 kcal/mol for succinate oxidation. These results are comparable to those reported for some mesophiles, and they suggest that the inability of the thermophile to grow at temperatures below about 41 C is not due to an abnormally high temperature coefficient for the uptake and oxidation of the carbon source.

The acute effects of sodium clofibrate (NaCPIB) on the metabolism of [1-14C]palmitate, [1-14C]octanoate, [1-14C]butyrate, and [2-3H]glycerol by freshly isolated hepatocytes were tested to explore its mechanism of action. Labeled long-, medium-, and short-chain fatty acids were incorporated into all the major lipid classes and were oxidized to 14CO2 by the liver cells. The partitioning of labeled fatty acids from lipogenic towards oxidative pathways was inversely related to fatty acid chain length. [1-14C]Palmitate was incorporated mainly into cellular triglycerides and phospholipids; [1-14C]octanoate, mainly into triglycerides and free cholesterol; and [1-14C]butyrate, mainly into free cholesterol and phospholipids of the cells. NaCPIB (1-3 mM) rapidly stimulated the esterification of labeled palmitate or glycerol to triglycerides, but drug levels greater than 5 mM were inhibitory to esterification. NaCPIB (1 mM) increased the oxidation of [1-14C]palmitate to 14CO2 by either rat or monkey hepatocytes and enhanced the release of labeled lipids from [2-3H]glycerol-prelabeled cells into the extracellular medium. Accelerated [1-14C]octanoate incorporation into glycerolipids and sterols and increased [1-14C]octanoate conversion to 14CO2 were observed in rat liver cells incubated with 1 mM NaCPIB. In contrast, the same drug level stimulated the oxidation of [1-14C]butyrate to 14CO2 but greatly diminished its incorporation into hepatocellular sterols or glycerolipids. These results indicate that (a) NaCPIB acutely alters hepatic ultilization of fatty acids by actions at diverse loci; (b) these metabolic alterations vary with fatty acid chain length; and (c) these effects are probably due to rapid changes in biochemical regulatory mechanism and/or in substrate channelling within the cells. These data further suggest that the early hypolipidemic effect of the drug in rats and primates may be related to an enhanced hepatic oxidation of long-chain fatty acids, but cannot be attributed simply to a reduction in their esterification to complex lipids.

Regulation of intracellular proteolysis has been compared during amino acid deficiencies in seven double auxotrophs of Escherichia coli 9723f with a common phenylalanine requirement. Individual deficiencies were either more effective than, less effective, or equal to phenylalanine deficiency in stimulating intracellular proteolysis. For each amino acid, the same relationship prevailed in inhibiting uracil incorporation into nucleic acids, a reaction series regulated by the rel gene for stringent control. The three amino acids least abundant in the cellular protein were the least effective regulators. These findings are interpreted as supportive evidence for stringent control of intracellular proteolysis by the rel gene.

The metabolism of (U--14C) glucose and its incorporation into acetylcholine were determined in vitro in fresh cortical biopsy samples from patients with Alzheimer's disease and controls. Synthesis of 14C acetylcholine was significantly reduced (60% and 67% reduction under stimulated and resting conditions, respectively) without significant changes in the overall metabolism of glucose (as measured by 14CO2 production). Acetylcholine synthesis was directly related to the activity of choline acetyltransferase. The changes in cholinergic markers reflected the severity of psychological defects. Acetylcholine synthesis was not reduced in biopsy samples from patients suffering from presenile dementia with no histological evidence of Alzheimer's disease.

Although reptiles rely heavily on anaerobic metabolism and lactic acid production during activity, little is known concerning their ventilatory response to the attendant metabolic acidosis. We measured arterial PCO2, H+ and lactate (L)ion concentrations, and the rates of CO2 (MCO2) and O2 (MO2) exchange in Varanus salvator (n = 9) during intravenous infusions of lactic acid (HL) or sodium lactate (NaL; 250 mM) at rest. Two protocols were used: (1) 15 min infusions of 0.42 ml/min at both 25 and 35 degrees C with measurements every 5 min; (2) 4.5 min infusions of 1.73 ml/min at 35 degrees C with measurements at 4.5 min. At 35 degrees C, control pH decreased from its value at 25 degrees C with a slope of -0.007/degrees C and PaCO2 increased. The results of HL infusion were: (1) [L]a increased, (2) MCO2 increased, (3) R (MCO2/MO2) increased, (4) pHa decreased, and (5) PaCO2 remained unchanged from control at both temperatures and at both infusion rates. The only significant changes in PaCO2 observed were following the termination of fast HL infusions, when PaCO2 decreased. In NaL infusions, only small changes were observed except in [L]a. The results indicate that: (1) delta pH/delta T in V. salvator is less than in other poikilothermic vertebrates, but consistent with other varanid lizards, (2) respiratory compensation is slight in response to acute metabolic acidosis in this species, and (3) ventilation follows changes in MCO2 rather closely, accounting for precise regulation of PaCO2 despite 4-fold increases in MCO2 elicited by bicarbonate buffering and increased metabolic rate.

Cultures of Cooperia punctata, a nematode parasitic in cattle, were studied in Ae medium at a pH of 7.2 to 7.3 under air. In fourth and fifth stages of development, they absorbed or otherwise took into their free pool and tissues, carbon derived from 14C-labeled sodium propionate and converted, by pathways not elucidated, a portion of this carbon into protein and lipid fractions. Thirty minutes postincubation in balanced slat solution was adequate to reduce the amount of isotope in the nematode gut to a constant level. Activity from specifically-labeled 14C-propionate was recovered (as glucose pentaacetate) from worm glucose and from CO2 evolved from cultures consisting of L4 and adult stages. Use of propionate by these worms, for whatever metabolic purpose, would result in depriving the ruminant host of some of its necessary glucogenic precursors, and could account for a specific pathogenic mechanism attendant to heavy infections with this parasite.

Ventrilatory requirement was assessed in 15 critically ill neonates on a total of 31 occasions. All were either currently receiving mechanical ventilation or had had mechanical ventilation in the recent past. Minute ventilation, respiratory frequency, carbon dioxide production (VCO2) and arterial blood PaCO2 were measured. Dead space-to-tidal volume ratios (VD/VT) were calculated. The ventilatory requirements of the infants ranged from 1.16 to 4.30 times normal. Derived parameters related the increased ventilatory requirement to pulmonary (VD/VT) and metabolic (VCO2) factors. The increased requirement was not significantly related more often to either of these two factors, although one or the other was frequently predominant in individual cases. Data presented allow specification of the minute volume range needed for ventilators designed for neonates, and the maximal compressible volume that can be tolerated when expired volume monitoring is desired.

Oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory quotient were measured in rats given a high-fat cafeteria diet of the type that is said to promote diet-induced thermogenesis. No significant difference in the measurements as compared with controls was found at room temperature, at 5 degrees C, or in animals exposed to cold for several weeks. The result was the same whether open- or closed-circuit methods were used. The stimulatory effect of norepinephrine on the VO2 was identical in each dietary group. These results cast doubt on the alleged identity of diet-induced and nonshivering thermogenesis and may reflect the change in body composition of the animals rather than a primary response to dietary variation.

Glucose metabolism and respiration of Candida albicans were compared under conditions which permitted either maximal filamentous or maximal yeast growth. Changes in metabolism were monitored by comparing the quantities of ethanol produced, CO2 evolved, and oxygen consumed. Filamenting cultures produced more ethanol and less CO2 than yeasts, with oxygen consumption in the former concomitantly slower than that of the latter. Studies involving cofactors and inhibitors associated with electron transport imply that a transfer of electrons away from flavoprotein is required for maintenance of yeast morphology. Conditions consistent with a buildup of reduced flavoprotein, however, favored filament formation. These changes were expressed metabolically as a shift from an aerobic to a fermentative metabolism. The results presented are consistent with hypotheses correlating filament production with changes in carbohydrate metabolism and an interruption of electron transfer within the cell.

The Y-ATP (energy efficiency) of intraperiplasmic growth of Bdellovibrio bacteriovorus was determined from the distribution of radioactivity of the substrate organism ([U-14C]Escherichia coli) btween CO2 and bdellovibrio cells at the end of growth. A "best" Y-ATP value of 18.5 was obtained from single growth cycle experiments and an average value of 25.9 from multicycle experiments. Both values are much higher than the usual value of 10.5 for bacteria growing in rich media. The bases for the unusual energy efficiency for growth of B. bacteriovorus are discussed.

The direct effects of the glucocorticoids hydrocortisone and corticosterone on myocardial metabolism were studied in cultured heart cells by assessing several parameters previously unreported. Hormone and growth factor concentrations were carefully controlled by using a serum-free medium, which also allowed maintenance of cells in the absence of glucocorticoids. Heart cell beating rate, glucose uptake rate, and CO2 evolution from radioactively labeled glucose were increased by the addition of 0.03 microM corticosterone to the medium of cells maintained in culture for 11 days. There were no further changes in these parameters as steroid concentration was increased to 14.43 microM. The activity of NAD-linked sn-glycerol-3-phosphate dehydrogenase (EC 1.1.1.8) was increased by both corticosteroids and was dose dependent between 0.06 and 1.44 microM corticosterone. The difference between glycerol-3-phosphate dehydrogenase activity in cells maintained with hydrocortisone as compared to cells maintained without hydrocortisone increased with days in culture. The protein and DNA contents of dishes maintained with corticosteroid were depressed, demonstrating an inhibitory effect on cellular replication. Glucocorticoids have numerous direct effects on cardiac cell metabolism, and the nature of these effects suggests that secondary responses of the cell to chronic exposure are significant.

Several probes for measuring dissolved carbon dioxide (CO2) concentration were installed in a 68-litre fermentor and their effectiveness compared. Submerged silastic rubber tubing gave reproducible results over a wide range of operating conditions and was generally superior to all other probes evaluated. The silastic rubber probe was used to compare the partial pressure of CO2 in viscous fermentation media with that in the fermentor exhaust gas. No significant difference was found. Results show that determination of the CO2 partial pressure in the exhaust gas gives an excellent approximation of the partial pressure of dissolved CO2 in the liquid medium, eliminating the need for measurement of CO2 concentration in the broth.

1-Benzyl-1-(3-dimethylaminopropoxy)cycloheptane (bencyclane-hydrogen-fumarate; Fludilat) in a concentration of 10-2 M effects an increase in the O2 consumption and the formation of CO2 in a 10% bovine lens homogenate. This effect is even increased if the glucose-substrate supply is raised from 25 mM to 37 mM. Investigations on the concentrations at ATP, ADP and AMP show that bencyclane is able to stabilize the physiologic distribution pattern of the three free adenine nucleotides. Further, the observed changes in the distribution pattern indicated that the fumaric acid rest of bencyclane may serve as a substrate for this reaction in the same way as fumarate.

The radiometric method has been applied for studying the metabolism of M. lepraemurium and the conditions which might force or inhibit its metabolic activity in vitro. These organisms assimilate and oxidize (U-14C) glycerol, and (U-14C) acetate, but are unable to oxidize (U-14C) glucose, (U-14C) pyruvate, (U-14C) glycine and 14C-formate. When incubated at 30 degrees C M. lepraemurium oxidizes (U-14C) acetate to 14CO2 faster than 37 degrees C. The smae effect was observed with increasing concentrations of polysorbate 80 (Tween 80), or the 14C-substrate. No change in metabolic rate was observed when the organisms were kept at -20 degrees C for 12 days. Although tried several times, it was not possible to demonstrate any "inhibitors" of bacterial metabolism in the reaction system. The radiometric method seems to be an important tool for studying metabolic pathways and the influence of physical and biochemical factors on the metabolism of M. lepraemurium in vitro.

Human T-lymphocytes activated by phytohemagglutin acquire insulin receptors in culture. Saturation analysis of insulin-binding activity in the presence of competing ligand revealed curvilinear Scatchard plots. Insulin receptors were not regulated by insulin before mitogen activation and culture of T-lymphocytes. However, insulin-induced downregulation of insulin receptors was: (1) demonstrable in receptor-positive cells, (2) dependent on insulin concentration, (3) temporally unrelated to insulin internalization, and (4) prevented by culture at 4 degrees C but not by cycloheximide at 37 degrees C. Recovery of insulin receptors required further culture of cells in media depleted of insulin for 24 h. Scatchard analysis revealed loss of receptor number without changes in receptor affinity. Insulin-induced increases in glucose transport and oxidation were demonstrable in receptor-positive cells but not in receptor-negative cells. However, these effects were extremely time-dependent. After a 2-h exposure of cells to 10(-8) M insulin, increases in glucose transport were no longer demonstrable. Elution of bound insulin from these cells followed by re-exposure to insulin depressed glucose transport in them. Recovery from this hyporesponsive, desensitized state required a 6-h culture in insulin-depleted media. Glucose oxidation of desensitized cells could be stimulated by spermine but not by insulin. These studies demonstrate the activated human T-lymphocyte is an insulin-sensitive tissue that is capable of limiting its physiologic response to insulin by receptor- and postreceptor-mediated mechanisms.

Slices of rat caudate nuclei were incubated in saline media containing choline, paraoxon, unlabelled glucose, and [1,5-14C] citrate, [1-14C-acetyl]carnitine, [1-14C]acetate, [2-14C]pyruvate, or [U-14C]glucose. The synthesis of acetyl-labelled acetylcholine (ACh) was compared with the total synthesis of ACh. When related to the utilization of unlabelled glucose (responsible for the formation of unlabelled ACh), the utilization of labelled substrates for the synthesis of the acetyl moiety of ACh was found to decrease in the following order: [2-14C]pyruvate greater than [U-14C]glucose greater than [1-14C-acetyl]carnitine greater than [1,5-14C]citrate greater than [1-14C]acetate. The utilization of [1,5-14C]citrate and [1-14C]acetate for the synthesis of [14C]ACh was low, although it was apparent from the formation of 14CO2 and 14C-labelled lipid that the substrates entered the cells and were metabolized. The utilization of [1,5-14C]citrate for the synthesis of [14C]ACh was higher when the incubation was performed in a medium without calcium (with EGTA); that of glucose did not change, whereas the utilization of other substrates for the synthesis of ACh decreased. The results indicate that earlier (indirect) evidence led to an underestimation of acetylcarnitine as a potential source of acetyl groups for the synthesis of ACh in mammalian brian; they do not support (but do not disprove) the view that citrate is the main carrier of acetyl groups from the intramitochondrial acetyl-CoA to the extramitochondrial space in cerebral cholinergic neurons.

Mineralization of native organic matter and U-14C-glucose was followed by measuring the formation of CO2 and its radioactivity in chernozem soil presterilized by gamma-radiation and inoculated with a washed suspension of Cellulomonas sp. cells. The introduced bacteria mineralized the soil organic component to a higher extent in variants enriched with glucose. This so-called priming effect of glucose was observed also in the presence of chloramphenicol, inhibiting the growth of the bacteria. The increased mineralization of the native soil organic fraction was also detected in samples that were not enriched with glucose when the bacterial suspension was first disintegrated ultrasonically and the material then used for the inoculation. Possible participation of phenomena of the type of cometabolism and activation of cell membrane transport mechanisms on the occurrence of the priming effect of glucose in the soil is discussed.

Seven burn patients treated with silver nitrate dressings were studied during the first 10 days after injury. Minute ventilation, oxygen consumption, and ventilatory equivalent were measured. Minute ventilation was increased two- to threefold, as was oxygen consumption. Ventilatory equivalent was only slightly increased. THree patients were initially treated with silver nitrate, and then, when clinically stable, were switched to Sulfamylon. They showed a 50% rise in ventilation, tidal volume, ventilatory equivalent, and a slight increase in respiratory rate and VD/VT. In addition, their PO2 increased and base excess fell. Five normal subjects were then given Diamox, and their minute ventilation, O2 consumption, and ventilatory equivalent were measured at rest, with a standard exercise, and with an added dead space. Diamox produced only a 25% increase in minute ventilation and ventilatory equivalent. The results suggest that, although some of the increased ventilation of Sulfamylon is due to carbonic anhydrase inhibition, another factor, such as pain casued by the topical agent, also plays a role.

Changes in metabolic rates (oxygen consumption, ketogenesis, 14CO2 production from labelled fatty acids, glycolysis) following the addition of octanoate or oleate were studied in isolated livers from fed and starved rats perfused with Krebs-Henseleit bicarbonate buffer in a non-recirculating system. The following results were obtained. The infusion of fatty acids caused a large increase in the rate of oxygen consumption. The effect was greater with octanoate than with oleate and was half-maximal with fatty acid concentrations (free plus albumin bound) around 0.1 mM. The effects of oleate were only partially suppressed when the perfusate contained albumin concentrations near the physiological range. When fatty acids were oxidized at high rates, the glycolytic rate was diminished by 50%. The increase in oxygen consumption could not be explained fully by the increased ATP demand for fatty acid metabolism or by a compensation for the diminished extramitochondrial ATP generation. In the presence of phenylalkyl oxirane carboxylic acid, an inhibitor of the transport of long-chain acyl-CoA derivates into the mitochondria, ketogenesis and 14CO2 production from labelled oleate were strongly inhibited, whereas the increase in oxygen consumption was only slightly affected. In the presence of antimycin A, the increase in oxygen consumption due to fatty acids was totally abolished. Following pretreatment of rats with ciprofibrate (induction of enzymes for peroxisomal beta-oxidation of long-chain fatty acids), ketogenesis (but not 14CO2 production) from oleate was enhanced threefold. The increase in oxygen consumption, however, was not affected. In conclusion, the increase in hepatic oxygen consumption due to addition of fatty acids reflects a mitochondrial process; it is, in part, independent of the ATP demand of the cell. An uncoupling-like effect of fatty acids on the respiratory chain and its possible physiological significance in ketogenesis are discussed.

Radiorespirometric and enzyme analyses were used to reveal the glucose-catabolizing mechanisms functioning in single strains of seven presumed Agrobacterium species. The Entner-Doudoroff and pentose cycle pathways functioned in A. radiobacter, A. tumefaciens, A. rubi, and A. rhizogenes. Whereas both catabolic pathways were utilized to an almost equal degree in the A. radiobacter and A. tumefaciens strains, use of the Entner-Doudoroff pathway predominated in the A. rubi and A. rhizogenes strains. A stellulatum catabolized glucose almost solely through the Entner-Doudoroff pathway. In A. pseudotsugae and A. gypsophilae, glucose was metabolized mainly through the Emden-Meyerhof-Parnas pathway; the pentose phosphate pathway was also utilized.

Glucose metabolism in Mycobacterium smegmatis was investigated by the radiorespirometric method and by assaying for key enzymes of the major energy-yielding pathways. Glucose is oxidized in this organism mainly through the Embden-Meyerhof-Parnas pathway, irrespective of the carbon source used for growth. The pentose phosphate pathway plays only a minor role and its extent depends on the carbon source used for growth. Enzymes of glycolytic and oxidative pathways were detected in cells grown on glucose, glycerol, or pyruvate but enzymes of the Entner-Duodroff pathway could be detected only in glucose-grown cells. Labeled acetate is utilized by cells cultured on glucose, glycerol, and pyruvate. In all cases more of C1 of acetate was converted to CO2 while incorporation into cellular constituents was maximum from C2 of acetate.

1. The metabolism of the 3-halopropan-1,2-diols (alpha-halohydrins) has been investigated in rats and mice. Apart from 3-chloropropan-1,2-diol (I), of which some 10% is excreted unchanged by both species, the compounds are completely degraded following intraperitoneal administration. 2. The alpha-halohydrins are detoxicated by conjugation with glutathione and produce two urinary metabolites, isolated and identified as S-(2,3-dihydroxypropyl)cysteine (VII) and the corresponding mercapturic acid N-acetyl-S-(2,3-dihydroxypropyl)cysteine (VIII). 3. When incubated with rat liver supernatant, the compounds do not conjugate with glutathione and their general chemical reactivity suggests that they react via a common intermediate proposed to be glycidol (2,3-epoxypropanol, IV). As the epoxide produces the same urinary metabolites as the alpha-halo-hydrins, and conjugates with glutathione either with or without liver supernatant to form the primary metabolite S-(2,3-dihydroxypropyl)glutathione (VI), glycidol is also proposed to be the reactive intermediate in vivo. 4. The role of epoxides in intermediary metabolism is discussed.

Glucagon has been shown previously to increase further the enhanced tolerance for hypoxia observed in mice with elevated blood ketones. Glucagon is also known to increase blood glucose and to alter directly the metabolism of some (liver) cells. Both the increase in blood glucose and altered cellular metabolism could contribute to the increase in tolerance for hypoxia observed in mice given glucagon in combination with the ketone, beta-hydroxybutyrate. To evaluate the systemic component of this hypothesis, blood glucose, beta-hydroxybutyrate, and glucagon were elevated alone or simultaneously and hypoxic tolerance of mice was measured. To identify possible cellular effects of glucagon on glucose or ketone metabolism, we measured the incorporation of radiolabeled glucose or beta-hydroxybutyrate into CO2 or total lipid in isolated rat brain slices. Both glucagon and glucose increased hypoxic tolerance of ketotic mice but our data do not support the hypothesis that glucagon's action was only through an elevation of blood glucose. In brain slices glucagon stimulated the incorporation of beta-hydroxybutyrate into CO2 both in the presence or absence of additional glucose. These results demonstrate that glucagon has a direct effect on brain metabolism which may contribute to the increased tolerance for hypoxia. They, however, do not exclude the possibility that glucagon is working in addition to increase hypoxic survival in ketotic mice by increasing the availability of glucose to the brain.