Distributional and stylistic variation in /r/-misarticulations: a case study.

This article describes the case of a client who displayed some interesting patterns of realization of the target English phoneme /r/. These varied according to both distribution within the word, and style of utterance. We speculate as to the cause of some of these forms, and on possible therapy strategies.

Effect of centrifugation at 2G for 14 days on metabolic enzymes of the tibialis anterior and soleus muscles.

Background: The enzyme composition of different muscle types vary greatly, leading to different changes of enzyme level caused by exposure to various stimuli.

Methods: Male Wistar rats were centrifuged at 2G in a 12-ft radius centrifuge for 14 d. Tibialis anterior (TA) and soleus muscles from four centrifuge and four control rats were analyzed for three enzymes characteristic of fast twitch muscles (phosphofructokinase, glycerol-3-phosphate dehydrogenase, and pyruvate kinase), and four enzymes characteristic of slow twitch muscles (hexokinase, mitochondrial thiolase, B-hydroxyacyl CoA dehydrogenase, and citrate synthase).

Myogenin induces a shift of enzyme activity from glycolytic to oxidative metabolism in muscles of transgenic mice.

Physical training regulates muscle metabolic and contractile properties by altering gene expression. Electrical activity evoked in muscle fiber membrane during physical activity is crucial for such regulation, but the subsequent intracellular pathway is virtually unmapped. Here we investigate the ability of myogenin, a muscle-specific transcription factor strongly regulated by electrical activity, to alter muscle phenotype.

Glutamate and potassium stimulation of hippocampal slices metabolizing glucose or glucose and pyruvate.

Using 2-deoxyglucose phosphorylation as an index of glucose use and concentrations of selected intermediates to monitor metabolic pathways, responses of rat hippocampal slices to glutamate and K+ stimulation were examined. With glutamate, the glucose phosphorylation rate (GPR) increased, and the slices accumulated glutamate at a constant rate, for 10 min. The uptake rate at each glutamate level was matched, approximately, by the increase in GPR at that level, with 4 or 5 glutamate molecules accumulated for every glucose molecule phosphorylated.

Metabolite changes associated with heat shocked avian fibroblast mitochondria.

A previous report from our laboratory (Collier et al 1993) showed that the elongated tubules of mitochondria in the cytoplasm of cultured chicken embryo fibroblasts collapsed to irregularly shaped structures surrounding the nuclear membrane after a 1 h heat shock treatment. The normal mitochondrial morphology reappeared upon removal of the thermal stress. We have now determined that several changes occurred in mitochondrial-related metabolites under these same heat shock and recovery conditions.

Changes in ATP, phosphocreatine, and 16 metabolites in muscle stimulated for up to 96 hours.

Rabbit tibialis anterior muscles were stimulated continuously at 10 Hz for periods ranging from 2 min to 96 h and were analyzed for energy reserves and metabolic intermediates. Glycogen, ATP and phosphocreatine fell rapidly during the first 5 min of stimulation. Glycogen continued to fall to very low levels, whereas ATP and phosphocreatine rose, reaching 70% of control by 1 h, despite ongoing stimulation.

Mitochondrial enzymes increase in muscle in response to 7-10 days of cycle exercise.

Endurance exercise training induces a significant increase in the respiratory capacity of skeletal muscle. This is reflected by a training-induced increase in mitochondrial enzyme activity. One consequence of this adaptation is that there is a decreased reliance on carbohydrate utilization with a concomitant increase in fat utilization, resulting in an improvement in endurance capacity.

Alterations of intraembryonic metabolites in preimplantation mouse embryos exposed to elevated concentrations of glucose: a metabolic explanation for the developmental retardation seen in preimplantation embryos from diabetic animals.

Preimplantation mouse embryos exposed to hyperglycemia, whether in vivo or in vitro, experience delayed development from the 2-cell to blastocyst stage. By comparing metabolites from embryos exposed to high vs. normal glucose conditions, a metabolic explanation for the delayed growth pattern was sought.

Administration of prostaglandin E1 after lung transplantation improves early graft function.

Early graft dysfunction continues to be a major clinical problem after lung transplantation. The objective of this experiment was to determine whether continuous administration of prostaglandin E1 (PGE1) after lung transplantation has a beneficial effect on early graft function. Left lung allotransplantation was performed in 10 size-matched mongrel dogs (weight, 24.

Effects of tetrodotoxin-induced neural inactivation on single muscle fiber metabolic enzymes.

Selected enzymes were measured in mixed-fiber bundles and individual fibers from rat plantaris (PL) and soleus (Sol) muscles that had undergone either 2 wk of tetrodotoxin (TTX) inactivation of the sciatic nerve, a sham operation, or were contralateral to the TTX limb. TTX disuse caused severe wasting of PL (46%) and Sol (26%) muscles and of single fibers (50% and 40%, respectively). TTX PL and Sol also had reduced (50%) glycogen content.

Ras signaling in the activation of glucose transport by insulin.

An approach involving microinjection and microanalysis has been developed to investigate signal-transduction pathways involved in the hormonal control of metabolism. We have applied this strategy to investigate the role of Ras signaling in the acute activation of glucose transport by insulin in cardiac myocytes. Glucose transport activity was assessed by measuring the initial rate of accumulation of 2-deoxyglucose 6-phosphate (dGlc6P) in individual cells after incubation in 2-deoxyglucose.

Glucose transport and phosphorylation in single cardiac myocytes: rate-limiting steps in glucose metabolism.

Microanalytic methods were used to investigate the regulation of glucose metabolism by insulin in single myocytes isolated from adult rat ventricles. Cultured myocytes were incubated with or without insulin and, with either glucose or 2-deoxyglucose (2-DG), rinsed, and freeze-dried. Individual cells were weighed and levels of 2-DG-6-phosphate (2-DG-6-P) or glucose and glucose 6-phosphate (G-6-P) were determined after enzymatic amplification.

An unusual active hexose transport system in human and mouse preimplantation embryos.

In a metabolic study of human and mouse preimplantation embryos (preembryos), we measured glucose uptake and phosphorylation with nonradioactive 2-deoxyglucose (DG) as tracer. Initial experiments indicated an active hexose transport capacity, a property thought to be restricted in mammals to intestinal villi and kidney tubules [Baly, D. L.

Enzyme activities and maturation in unstimulated and exogenous gonadotropin-stimulated human oocytes.

With the advent of new techniques of human in vitro fertilization (IVF), identifying parameters of oocyte quality to allow selection of those most likely to fertilize becomes crucial. Morphology of oocytes, which correlates positively with biological performance, is the currently utilized classification criterion. However, biological links between form and function are tenuous, and underlying mechanisms remain elusive.

A refinement of the Akabayashi-Saito-Kato modification of the enzymatic methods for 2-deoxyglucose and 2-deoxyglucose 6-phosphate.

Akabayashi et al. made a valuable modification of the enzymatic methods from our laboratory for measuring 2-deoxyglucose and 2-deoxyglucose 6-phosphate. Their modified procedure eliminates glucose and glucose 6-phosphate by conversion to fructose-1,6-bisphosphate, thereby saving two analytical steps.

Changes in alveolar oxygen and carbon dioxide concentration and oxygen consumption during lung preservation. The maintenance of aerobic metabolism during lung preservation.

The lung is the only organ to which oxygen may be supplied after its blood supply is stopped. Before this study, we were not certain whether lung cells were able to maintain aerobic metabolism with the oxygen in the alveoli during preservation. Excised rabbit lungs were used to measure changes in the concentration of oxygen and carbon dioxide in the airway and changes in glucose, glucose-6-phosphate, lactate, adenosine triphosphate, and phosphocreatine levels in the lung tissue during preservation under different conditions.

Evaluation of lung metabolism during successful twenty-four-hour canine lung preservation.

We used a canine left lung allotransplantation model to evaluate 24-hour lung preservation with two different electrolyte solutions, low-potassium dextran and low-potassium dextran with 1% glucose. To investigate changes in the energy status during preservation, we analyzed the lungs for adenosine triphosphate, phosphocreatine, and several metabolites of the glycolysis pathway and the citric acid cycle: glucose, glucose-6-phosphate, lactate, citrate, and malate. We also devised and evaluated a pulmonary cooling jacket to prevent rewarming of the lung during implantation.

Glucose metabolism assessed with 2-deoxyglucose and the effect of glutamate in subdivisions of rat hippocampal slices.

A new approach to the study of glucose phosphorylation in brain slices is described. It is based on timed incubation with nonradioactive 2-deoxyglucose (DG), after which the tissue levels of DG and 2-deoxyglucose-6-phosphate (DG6P) are measured separately with sensitive enzymatic methods applied to specific small subregions. The smallest samples had dry weights of approximately 0.

Effects of microgravity and tail suspension on enzymes of individual soleus and tibialis anterior fibers.

Selected enzymes of energy metabolism were measured in random individual fibers of soleus and tibialis anterior (TA) muscles from rats exposed for 2 wk to spaceflight (F) aboard COSMOS 2044 or tail suspension (T) and from synchronous controls. Average size of soleus fibers (dry weight per unit length) was reduced 37% in F and T fibers; there was little change in TA fibers. Enzyme changes were more pronounced in soleus than in TA fibers.

Enzyme levels in cultured astrocytes, oligodendrocytes and Schwann cells, and neurons from the cerebral cortex and superior cervical ganglia of the rat.

Data are presented for 16 enzymes from 8 metabolic systems in cell cultures consisting of approximately 95% astrocytes and 5% oligodendrocytes. Nine of these enzymes were also measured in cultures of oligodendrocytes, Schwann cells, and neurons prepared from both cerebral cortex and superior cervical ganglia. Activities, in mature astrocyte cultures, expressed as percentage of their activity in brain, ranged from 9% for glycerol-3-phosphate dehydrogenase to over 300% for glucose-6-phosphate dehydrogenase.

Distribution in brain and retina of four enzymes of acetyl CoA synthesis in relation to choline acetyl transferase and acetylcholine esterase.

Eleven regions of mouse brain and twelve layers of monkey retina were assayed for choline acetyl transferase (ChAT), acetylcholine esterase (AChE), and 4 enzymes that synthesize acetyl CoA. The purpose was to seek evidence concerning the source of acetyl CoA for acetylcholine generation. In brain ATP citrate lyase was strongly correlated with ChAT as well as AChE (r = 0.

Sepsis does not impair tricarboxylic acid cycle in the heart.

Sepsis has been reported to cause mitochondrial dysfunction and inhibition of key enzymes that regulate the tricarboxylic acid (TCA) cycle. We investigated the effect of sepsis on high-energy phosphates, glycolytic and TCA cycle intermediates, and specific amino acids that are involved in regulating the size of the TCA cycle pool during changes in metabolic state of the heart. Sepsis was induced in 12 female rats by the cecal ligation and perforation technique under halothane anesthesia; seven control rats underwent cecal manipulation without ligation.

Measurement of 2-deoxyglucose and 2-deoxyglucose 6-phosphate in tissues.

The enzymatic methods previously described for 2-deoxyglucose (DG) and 2-deoxyglucose 6-phosphate have been refined and adapted to measurements of brain samples ranging from 50 mg wet weight to less than a microgram dry weight. Procedures for preparing such samples for assay are described. Analytical properties of the enzymes employed are given together with means for overcoming their possible short comings.