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Biomedical subjects

N M White

Publications and source records attributed to N M White.

68 records · Page 4Linked to original sources
PubMed1985

Short- and long-term effectiveness of enteral and parenteral nutrition in reversing or preventing protein-energy malnutrition in advanced neuroblastoma. A prospective randomized study.

The effectiveness of enteral and parenteral nutrition regimens in preventing or reversing protein-energy malnutrition (PEM) and in preventing treatment delays was evaluated in 32 children receiving treatment for newly diagnosed Stage III (3 patients) and IV (29 patients) neuroblastoma. Ten of 18 malnourished patients were randomized to central parenteral nutrition (CPN) and 8 to peripheral parenteral nutrition (PPN) plus enteral nutrition for 4 weeks and then received enteral nutrition (EN: intense nutrition counselling, oral foods and supplements) for weeks 5 through 10. Ten of 14 nourished patients received EN and 4 CPN for 4 weeks and EN thereafter. Dietary, anthropometric and biochemical measurements were determined for weeks 0, 1, 2, 3, 4, 7, and 10 for 24 patients who completed the protocols. In malnourished patients, both CPN (seven patients) and PPN (seven patients) were effective in reversing PEM in the first 4 weeks; thereafter, EN effectively maintained nutritional gains in both groups. In nourished patients, EN (seven patients) was not as effective as CPN (three patients) in preventing PEM during the first 4 weeks; afterwards, EN maintained gains in the CPN group but did not promote needed increases in weight nor fat reserves in the EN group. Patients supported by parenteral nutrition (PN, weeks 1-4) had fewer treatment delays (2/17, 12%) than EN patients (4/7, 57%, P less than 0.05). These data indicate that PN reverses or prevents PEM and prevents treatment delays during the first 4 weeks of intense oncologic treatment and provides nutritional benefits which can be maintained with EN thereafter.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

The conditioned place preference is affected by two independent reinforcement processes.

The conditioned place preference method for measuring the affective properties of reinforcing events was studied using treatments of known affective value. The size of the place aversion observed increased with dose when the reinforcer was injections of lithium chloride. The size of the place preference observed increased with concentration when the reinforcer was drinking sucrose solutions. However, when the reinforcer was solutions of saccharin (that were consumed in the same amounts as the sucrose solutions) no place preferences were observed. This finding was explained in terms of the dual reinforcement hypothesis [20] which postulates that although sucrose and saccharin both have positive affective properties (based on their tastes) only sucrose has memory improving properties (based on its post-ingestive action). It was therefore proposed that conditioned place preferences depend on the activation of both affective and memory improving processes. This hypothesis was confirmed by the observation of place preferences with a saccharin solution as the reinforcer when the pairing trials were followed by non-contingent, post-pairing injections of glucose or amphetamine (both of which are known to improve memory). Therefore, behavior in the place preference method depends upon both the affective and the memory improving properties of the reinforcers under test.

Affect↗
PubMed1984

The relationship between stereotypy and memory improvement produced by amphetamine.

This study examined the possibility that amphetamine-induced stereotypy and facilitation of memory consolidation are both mediated by amphetamine's stimulation of dopaminergic activity in the caudate nucleus. In the first experiment, rats were given pairings of a tone and a shock followed by SC amphetamine (2 mg/kg). The amount of stereotypy and increased locomotor activity produced by the injection were measured immediately. Retention of the tone-shock association was evaluated 48 h later by observing the ability of the tone to suppress drinking. The degree of retention was significantly correlated with the amount of stereotypy but not with the amount of locomotion previously measured. In the second experiment, amphetamine was microinjected into the caudate nucleus (10 micrograms/microliters) and its ability to produce the same three behavioral effects was examined. These injections produced increased stereotypy and improved retention, but no increase in locomotion. The correlation of memory facilitation with stereotypy and the fact that both were produced by intracaudate amphetamine suggest that they may be mediated by the same neuropharmacological substrate, namely amphetamine-induced release of dopamine in the caudate.

Amphetamine↗
PubMed1984

Contingent and non-contingent actions of sucrose and saccharin reinforcers: effects on taste preference and memory.

Preference curves were generated by comparing 14 concentrations each of sucrose and saccharin in a 20-minute test in which rats were presented with a choice of a sweet solution and water. The most preferred concentration and one concentration above and one below the most preferred for both substances were studied further. The sucrose and saccharin solutions were contingently paired with novel flavors in a conditioned taste preference (CTP) paradigm. All of the sweet solutions enhanced the animals' subsequent conditioned taste preferences for the flavors. The lack of difference between the effects of the solutions in this paradigm suggest that they had similar rewarding values and that CTP's are established mainly on the basis of taste cues. In another experiment, post-training ingestion of sucrose solutions, injection of glucose and, to a much lesser extent, ingestion of saccharin solutions retroactively and non- contingently improved retention of a previously formed, classically conditioned association. The results indicated that this effect was mainly due to the post- ingestional effects of the sucrose solutions, although taste factors also had a slight influence. This series of experiments parallels previous findings with self-stimulation as the reinforcer. The results support the hypothesis that reinforcers have a dual action on behavior: the elicitation of affective states that, when paired with environmental stimuli, can influence future behavior towards those stimuli; and a non-contingent retroactive enhancement of retention of previously formed associations.

Animals↗
PubMed1983

Conditioned place preference from intra-accumbens but not intra-caudate amphetamine injections.

Rats received injections of d-amphetamine sulphate (10 micrograms in 0.5 ul) in nucleus accumbens and were placed into one of two (randomly assigned) distinctive environments. The next day the rats were placed into the other environment and received either a saline injection or no treatment. This procedure was repeated six times. When the rats were allowed a free choice between the two environments they showed a significant preference for the one that had been paired with amphetamine. This finding suggests that amphetamine-stimulated release of dopamine in nucleus accumbens can increase the incentive value of neutral stimuli with which it is paired. When the same procedure was carried out with a group of rats that received amphetamine injections in the dorsolateral caudate nucleus, no preference for the side paired with the drug was evident. This suggests that there is functional differentiation between different parts of the dopaminergic terminal system.

Animals↗
PubMed1983

Effect of nutrition staging on treatment delays and outcome in Stage IV neuroblastoma.

The effect of the state of nutrition of 18 children with Stage IV neuroblastoma at diagnosis and during initial therapy, was evaluated with respect to treatment delays, drug dosage alterations, tumor response, days to first event (relapse or death), and survival. All patients received similar therapy (CCSG protocol CCG 371). Based on nutrition staging at diagnosis, nine were classified as malnourished; four were randomized to receive total parenteral nutrition (TPN) and four peripheral parenteral nutrition plus enteral nutrition for 28 days (through 2 chemotherapy courses), and one died before randomization. Nine were nourished at diagnosis; seven received a comprehensive enteral nutrition program and two received TPN. By life-table analysis, the duration of remission was significantly greater in the nourished than the malnourished (P less than 0.01) and a trend towards improved survival was evident at one year (P = 0.08). The median length of survival for children nourished at diagnosis was approximately 12 months, whereas those malnourished had a median survival of only 5 months. Nine children remained nourished or were becoming renourished during the first 21 days of therapy, and one of these had treatment delays and decreased drug dosages. Seven were becoming malnourished or remained malnourished during this period and six had treatment delays (P less than 0.01). These data support the idea that nutrition staging at diagnosis and during initial treatment should be an integral part of protocol design and initial evaluation of children with Stage IV neuroblastoma.

Abdominal Neoplasms↗
PubMed1983

Effectiveness of central parenteral nutrition versus peripheral parenteral nutrition plus enteral nutrition in reversing protein-energy malnutrition in children with advanced neuroblastoma and Wilms' tumor: a prospective randomized study.

The effectiveness of central parenteral nutrition (CPN) versus peripheral parenteral nutrition (PPN) plus enteral nutrition in reversing protein-energy malnutrition was evaluated in 19 children (nine CPN, 10 PPN) with advanced neuroblastoma or Wilms' tumor. Weekly dietary, anthropometric, and biochemical measurements were compared for 15 patients (eight CPN, seven PPN) who completed more than 25 days of nutrition support. The groups had similar mean energy and protein intakes (CPN: 95 +/- 5% of healthy children, 2.5 +/- 0.3 g/kg; PPN: 102 +/- 5% of healthy children, 2.9 +/- 0.3 g/kg). Increases in weight (p less than 0.001), subscapular skinfold thickness (p less than 0.001), albumin (p less than 0.05), and transferrin (p less than 0.05) for the first 28 days were significant and did not differ between groups. Fever, sepsis, elevated SGOT, and severe anemia occurred with both CPN and PPN. PPN resulted in subcutaneous infiltrations and more psychological trauma. PPN with enteral nutrition seems most appropriate for short term intravenous nutrition support or as a temporary substitute for CPN; CPN is preferred for long-term support.

Body Weight↗
PubMed1973

Mobile coronary care provided by ambulance personnel.

Mobile coronary care has been provided in Brighton by ambulance personnel without immediate help from physicians or nurses. No additional vehicles or staff were required. The capital cost of the experiment was therefore small and additional running costs were negligible. The results have been monitored by retrospective analysis of electrocardiograms recorded in the ambulance and stored on magnetic tape. In the first 12 months of operation to July 1972, 1,082 patients with suspected cardiac emergencies were carried in two vehicles. Subsequent analysis showed that 76% of these patients had acute symptoms from ischaemic heart disease or had circulatory arrest. Eighty-six per cent. of arrhythmias were diagnosed correctly by the ambulance attendants. Though only eight cases of primary ventricular fibrillation occurred during or shortly before transit all were successfully reversed, and five of these patients subsequently left hospital alive. Other benefits of the scheme have included an appreciable reduction in the median delay between onset of presenting symptoms in patients with acute myocardial ischaemia and their admission to hospital.

Allied Health Personnel↗
PubMedDate not supplied

Reward or reinforcement: what's the difference?

The histories of the terms "reward" and "reinforcement" are reviewed to show the difference in their origins. Reward refers to the fact that certain environmental stimuli have the property of eliciting approach responses. Evidence suggests that the ventral striatum (nucleus accumbens area) is central to the mediation of this behavior. Reinforcement refers to the tendency of certain stimuli to strengthen learned stimulus-response tendencies. The dorsolateral striatum appears to be central to the mediation of this behavior. Neuroanatomical and neurochemical data are adduced suggesting that reward may be mediated by a neural circuit including the neostriatal patch system, together with the hippocampus, limbic system (amygdala, prefrontal cortex) and ventral pallidum. The evidence also suggests that reinforcement, in the form of dopamine release in the striatal matrix, acts to promote the consolidation of sensori-motor associations. Thus, the matrix may mediate stimulus-response memory as part of a circuit including the cerebral cortex, substantia nigra pars reticulata and its projections to thalamic and brainstem motor areas.

Animals↗
PubMedDate not supplied

Alcohol plus cocaine prenatally is more deleterious than either drug alone.

A C57BL/6J mouse model was used to examine the coteratology of alcohol and cocaine. Plugged female mice were assigned to one of four treatment groups: control, cocaine only, alcohol only, or alcohol-cocaine. Experimental animals were treated from gestation day (GD) 6-18 and were killed the morning of GD 19. Alcohol was administered in a liquid diet containing 25% ethanol-derived calories (25% EDC), and cocaine was administered daily in subcutaneous injections of 60 mg/kg. All groups were pair-fed to the alcohol-cocaine group. The results showed that the cocaine-only and the alcohol-cocaine group had fewer successful pregnancies. The alcohol-only group had the lowest maternal weight gain from GD 1-19. There were no treatment group effects on litter size, sex ratio, or prenatal mortality. Importantly, fetuses in the alcohol-cocaine group weighed less than all other groups and had the greatest occurrence of fetal anomalies. These data confirm the teratogenic effects of alcohol and cocaine and suggest that the combination of the two drugs, if administered chronically, is more deleterious to pregnancy and fetal outcome than either drug alone.

Abnormalities, Drug-Induced↗