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Biomedical subjects

L Fox

Publications and source records attributed to L Fox.

At least 73 records · Page 4Linked to original sources

Mechanism of aluminum-induced inhibition of hepatic glycolysis: inactivation of phosphofructokinase.

Aluminum, an abundant element in the earth's crust, has been implicated in various pathological disorders and low concentrations of this element have recently been shown to inhibit brain glycolysis. However, despite the fact that aluminum accumulates in high concentrations in the liver, potential effects of this metal on hepatic intermediary metabolism have not been explored. In perfused livers from untreated rats, maximal rates of production of lactate plus pyruvate (glycolysis) were 93 +/- 15 mumols/g/hr. Glycolysis was severely inhibited in livers from aluminum-treated rats (0.5 mg/kg, 6 hr before experiment) with maximal rates of only 23 +/- 4 mumols/g/hr. In contrast, glucose production (glycogenolysis) and hepatic oxygen uptake were not altered significantly by prior treatment with aluminum. In livers from fasted rats, pretreatment with aluminum did not influence gluconeogenesis or production of lactate and pyruvate from fructose (5 mM). This finding indicates that pyruvate kinase is not inhibited by aluminum and implicates phosphofructokinase, hexokinase and/or glucokinase as sites for the inhibitory effect of aluminum on glycolysis. In liver homogenates from untreated rats, increasing concentrations of aluminum did not show any appreciable effect on hexokinase or glucokinase activity but did cause progressive decreases in phosphofructokinase activity. Therefore, aluminum-induced inhibition of liver phosphofructokinase, an important control site in the glycolytic pathway, is most likely responsible for aluminum-induced inhibition of hepatic glycolysis.

Adenosine Triphosphate↗

Patterns of language comprehension deficit in abused and neglected children.

The similarity between factors associated with child abuse/neglect and those associated with language disability suggests that maltreated children are a population at risk for language problems. This study investigated the performance of three groups of abused/neglected children and a matched group of nonmaltreated subjects on three tests of language comprehension. Results revealed significant differences among groups for all measures. Severely neglected children obtained the lowest scores on all tests; the abused children consistently obtained lower scores than the controls; and generally neglected children showed the smallest difference in performance from the control group. These findings suggest a model for understanding relationships between abuse/neglect and language disability.

Child↗

Ten-year experience with extracorporeal membrane oxygenation for severe respiratory failure.

In the last ten years, 17 patients with respiratory failure refractory to standard ventilator therapy have been treated with extracorporeal membrane oxygenation (ECMO) at the Toronto General Hospital. One patient was treated with ECMO twice. Four perfusions were veno-arterial, the remainder veno-venous. Perfusions ranged from 1 1/2 to 19 days, with a mean of six days. Ten patients died during treatment or soon after it was discontinued. Eight patients improved enough to allow resumption of standard ventilation, and four patients recovered sufficiently to have normal arterial blood gas levels on room air. Three are long-term survivors. Multiple surgical procedures have been performed successfully during use of ECMO including lung lavage, open lung biopsy and three lung transplants. Major complications include hemorrhagic diatheses and sepsis. The technique involves a substantial commitment of time and personnel but remains a tenable option for presumed reversible life-threatening respiratory failure.

Adolescent↗

Personalising the service--the Trent initiative.

Liz Fox, who has been working with Trent RHA as its external consultant, describes its campaign to introduce the philosophy of personal service throughout the region, providing opportunities for NHS management and staff to personalise the service they provide.

Consumer Behavior↗

Enhancing cancer pain control regimens through patient education.

The problem of cancer-related pain afflicts millions of people annually. The study described here was aimed at improving cancer patients' pain control through a planned patient education program. A randomized clinical trial with a Solomon Four-Group design was used to assess the effectiveness of a patient education intervention consisting of nurse counseling and printed materials. The sample included 230 cancer patients. One month later, patients in the experimental group were more likely to have taken their pain medicine on the correct schedule and to have taken the correct dosage. The experimental group also was significantly less likely to report stopping the medicine when they felt better. In addition, they were significantly less worried about tolerance and addiction to pain medicines. Forty-four percent of the experimental group compared to 24% of the control group reported no or mild pain at the posttest.

Aged↗

Synaptic ribbon populations in the pineal gland of the rhesus monkey (Macaca mulatta).

Pinealocytes of rhesus monkeys that had been ovariectomized and given intramuscular injections of 250 micrograms estradiol-benzoate for 3 consecutive days tended to have more synaptic ribbons (SR) and exhibited a significantly greater size of ribbon fields (RF) compared to untreated animals. These data are consistent with hypotheses that pinealocyte function in primates is altered by hormonal imbalances and that the SR participates in this response. RF were positioned in various parts of the cytoplasm and along the plasma membrane. Participation of SR in direct cell-to-cell contacts was suggested by the formation of densities along the plasma membrane. It is postulated that large RF serve as storage organelles and that the formation of RF results from division of pre-existing SR in each field. Reconstructions made from serial thin sections revealed that profiles of RF comprised separate SR that were not folded and sectioned along various planes.

Animals↗

Prolonged cardiac arrest and resuscitation in dogs: brain mitochondrial function with different artificial perfusion methods.

Clinical techniques for artificial perfusion have not previously been examined directly for their effects on brain high-energy metabolism. Our study involved 24 large mongrel dogs that were anesthetized, instrumented for central venous intravenous access, and subjected to craniotomy to expose the dura and underlying parietal cortex. The animals were divided into the following six experimental groups of four animals each: nonischemic controls; 15-minute cardiac arrest without resuscitation; 45-minute cardiac arrest without resuscitation; 15-minute cardiac arrest plus 30 minutes resuscitation with conventional cardiopulmonary resuscitation (CPR); 15-minute cardiac arrest plus 30 minutes resuscitation with interposed abdominal compression (IAC) CPR; and 15-minute cardiac arrest plus 30 minutes resuscitation with internal cardiac massage. Cardiac arrest was induced by central venous injection of KCl 0.6 mEq/kg, and it was confirmed by continuous ECG monitoring. The three active resuscitation models included administration of NaHCO3 and epinephrine, but no attempt was made to restart the heart by defibrillation during resuscitation. At the indicated time in each group, a 4- to 5-g sample of brain was removed through the craniotomy, immediately cooled to 0 C and processed for isolation of mitochondria. The mitochondria were studied for their content of superoxide dismutase and for quantitative oxygen consumption with glutamate/malate substrate during resting and ADP-stimulated respiration. Our results show a significant drop in brain mitochondrial superoxide dismutase activity during the first 15 minutes of cardiac arrest. There is minimal injury to brain mitochondrial oxygen consumption during both 15 and 45 minutes of complete ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Antiserum to lens antigens immunostains Müller glia cells in the neural retina.

Antiserum to a lens fraction enriched for alpha-crystallin selectively immunostains Müller glia cells in the neural retina of several vertebrate species. Also, in embryonic retina (chicken), this antiserum reacts with Müller cells and, at early stages of development, with their apparent precursors. Thus, antibodies to a lens product(s) detect a Müller glia cell marker that begins to be expressed very early in their ontogeny and can be useful in studies on differentiation, function, and pathologies of this cell type.

Animals↗

Pineal ultrastructure and indole profiles spanning the summer rise in arginine vasotocin immunoactivity.

A correlative radioimmunological-biochemical-ultrastructural study of the rat pineal gland was undertaken during the summer months when pineal arginine vasotocin (AVT) immunoactivity increases up to 200-fold. RIA confirmed a rapid rise in AVT activity during mid-August regardless of the time of day sampled. Pineal indoles were separated by HPLC and measured using electrochemical detection. Serotonin (5-HT) and 5-hydroxyindoleacetic acid levels were consistently elevated in daytime samples, and there was a significant trend for increased day and nighttime levels of 5-HT from July to September. Mid-dark levels of melatonin also exhibited a significant increase over the sample period. Nighttime levels of N-acetylserotonin mirrored fluctuations in 5-HT in the preceding photoperiod. Ultrastructural components implicated in peptide/protein and/or indole biosynthesis were quantified by stereological morphometry. The greatest amounts of rough endoplasmic reticulum stacks, lipid droplets, and annulate lamellae-like bodies coincided with peak AVT activity. Dense-cored vesicles and synaptic ribbons were consistently more frequent during the dark period. The number of dense-cored vesicles and nucleolar size tended to be greatest before and after the peak in AVT immunoactivity. These observations are consistent with the hypotheses that endoplasmic reticulum and lipid are functionally related to the synthesis and/or storage of peptide/protein factors and that numerical changes in synaptic ribbons and dense-cored vesicles are more closely related to day/night differences in indole metabolism.

5-Hydroxytryptophan↗

Fulminant meningococcemia in children.

In all respects, the child with fulminant meningococcemia presents a formidable challenge to those who care for him/her. Only with prompt recognition of the disease and immediate institution of intensive treatment can the likelihood of survival be improved and morbidity minimized.

Anti-Bacterial Agents↗