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Biomedical subjects

L Adams

Publications and source records attributed to L Adams.

At least 127 records · Page 7Linked to original sources
PubMed1991

Altered gastric emptying in the head-injured patient: relationship to feeding intolerance.

Most patients with moderate to severe head injury initially do not tolerate enteral feedings postinjury. This intolerance is more prolonged than that found in patients suffering other types of trauma. The authors prospectively evaluated 12 patients with moderate to severe head injury (Glasgow Coma Scale score between 4 and 10) throughout their hospitalization for liquid gastric emptying as a possible mechanism for intolerance to enteral feeding. During Week 1, the majority of patients displayed a delay in gastric emptying. Patients also displayed an abnormal biphasic response (gastric emptying faster than normal during the early stage but prolonged later). By Week 2, many patients still had delayed and abnormal biphasic responses to gastric emptying. By Week 3, an improvement was observed with the majority of patients exhibiting rapid gastric emptying, but delays and abnormal biphasic responses were still seen. Patients who initially had rapid or normal gastric emptying tolerated full-strength full-rate feedings significantly earlier compared with those who experienced delayed gastric emptying (8.5 +/- 0.5 days vs. 13.7 +/- 3.2 days, p less than 0.001). All patients tolerated full-strength full-rate feedings by Day 16 postinjury (range 7 to 16 days) except the two patients who displayed delayed gastric emptying for prolonged periods of time (mean 25 days). This is the first study to longitudinally evaluate gastric emptying following head injury. The authors suggest that patients with moderate to severe head injury often experience alterations in gastric emptying which may affect their ability to tolerate enteral feedings.

Adolescent↗
PubMed1990

Interferon alpha-2a and 5-fluorouracil for advanced colorectal carcinoma. Assessment of activity and toxicity.

Preclinical data showed that the cytotoxic effects of 5-fluorouracil (5-FU) are augmented by interferon (IFN). In a small study, 13 of 17 patients with advanced colorectal cancer responded to a regimen of 5-FU with IFN. Using the same dose and schedule as in this pilot study, 38 previously untreated patients with metastatic colorectal carcinoma were treated with continuous intravenous (IV) infusion of 5-FU 750 mg/m2 daily for 5 days, followed by weekly bolus 5-FU at 750 mg/m2 and subcutaneous IFN at 9 million units three times per week. Of 35 evaluable patients, nine (26%) had a partial response (95% confidence limit, 11% to 41%), with a median response duration of 7.5 months (range, 4.4 to greater than 11.7 months). Seven patients (20%) had a minor response, and ten (28%) had stable disease. The most common toxicities observed were stomatitis (52%) and diarrhea (43%). Neurotoxicity was seen in 34% of patients and consisted of gait disturbance, dizziness, confusion, memory loss, and dementia. Because of toxicity, 84% of patients required a reduction of the IFN dose by at least 50%, and 63% required reduction of the 5-FU dose by at least 25%. Although the combination of 5-FU and IFN in patients with advanced colorectal carcinoma has some activity, the regimen was toxic, and the observed response rate (26%) was not substantially superior to alternative 5-FU programs.

Adult↗
PubMed1990

'Air hunger' from increased PCO2 persists after complete neuromuscular block in humans.

The tolerance of totally curarized subjects for prolonged breath hold is viewed by many as evidence that respiratory muscle contraction is essential to generate the sensation of breathlessness. Although conflicting evidence exists, none of it was obtained during total neuromuscular block. We completely paralyzed four normal, unsedated subjects with vecuronium (a non-depolarizing neuromuscular blocker). Subjects were mechanically ventilated with hyperoxic gas mixtures at fixed rate and tidal volume. End-expiratory PCO2 (PETCO2) was varied surreptitiously by changing inspired PCO2. Subjects rated their respiratory discomfort or 'air hunger' every 45 sec. At low PETCO2 (median 35 Torr) they felt little or no air hunger. When PETCO2 was raised (median 44 Torr) all subjects reported severe air hunger. They had reported the same degree of air hunger at essentially the same PETCO2 before paralysis. When questioned afterwards all subjects said the sensation could be described by the terms 'air hunger', 'urge to breathe', and 'shortness of breath', and that is was like breath holding. They reported no fundamental difference in the sensation before and after paralysis. We conclude that respiratory muscle contraction is not important in the genesis of air hunger evoked by hypercapnia.

Adult↗
PubMed1990

Exclusion of the autosomal dominant retinitis pigmentosa gene from a substantial region of chromosome 1: study of a large Australian family.

In an attempt to map the gene(s) responsible for autosomal dominant retinitis pigmentosa (ADRP), the technique of reverse genetics was used on a large multigenerational Australian pedigree. The family demonstrated a form of the disease which appears to be less severe than that observed in the Irish pedigree. It was typed for 10 restriction fragment length polymorphism (RFLP) markers on chromosome 1. The data from the linkage study was analysed using the programs LIPED 3; six markers gave informative results. The ADRP gene was excluded from this family from 102 cM using previously prepared chromosome 1 maps. This accounts for 36% of chromosome 1 which is estimated to be the longest human chromosome.

Adolescent↗
PubMed1990

Putative cerebral cortical involvement in the ventilatory response to inhaled CO2 in conscious man.

1. The response of the diaphragm to both transcranial magnetic stimulation and electrical phrenic nerve stimulation was studied in thirteen normal subjects under conditions of either a 'reflex' drive to ventilation with inhaled CO2 or during volitional ventilation of similar magnitude. 2. The induced compound action potential in the diaphragm was recorded using an oesophageal electrode, and in some cases transdiaphragmatic pressure was recorded using oesophageal and gastric balloon catheters. 3. The response of the diaphragm to transcranial magnetic stimulation was invariably facilitated with volitional inspiration; there was either minimal or no response at functional residual capacity. 4. Facilitation with inspiration was also seen during a 'reflex' drive to ventilation with inhaled CO2 in the presumed absence of any volitional contribution to ventilation. A similar degree of facilitation was seen with voluntary ventilation of similar magnitude and pattern. 5. If the facilitation is predominantly a cortical phenomenon, then these results imply that there is a behavioural component in the previously supposed purely 'reflex' drive to ventilation with inhaled CO2. We also discuss the interpretation of these results if some of the facilitation occurs at the phrenic motoneurone.

Action Potentials↗
PubMed1990

The effects of hypoxia and hypercapnia on perceived breathlessness during exercise in humans.

1. The sensation of breathlessness increases when ventilation is reflexly stimulated but it is not clear whether different stimuli have specific effects in the genesis of this sensation. 2. Our aim was to compare subjective assessments of the intensity of breathlessness at the same levels of ventilation induced by different combinations of reflex ventilatory stimuli. 3. Against a background of progressive exercise (maximum workload 170 W) in 'blinded' normal naive subjects, normoxic hypercapnia (maximum end-tidal CO2, PET, CO2, 56 mmHg) or isocapnic hypoxia (minimum O2 saturation 88%) was induced to achieve levels of ventilation (maximum 60 l min-1) 'matched' with those resulting from a higher intensity of exercise alone. Subjective breathlessness was rated with a visual analogue scale. 4. For a given ventilation, compared with exercise alone, breathlessness scores were similar during hypercapnia and were lower during hypoxia. 5. These results do not support the idea that during exercise, hypercapnia or hypoxia has a specific role in the genesis of the sensation of breathlessness. 6. The findings are consistent with the hypothesis that the degree of reflex ventilatory activation, however achieved, is an important determinant of the intensity of perceived breathlessness in healthy humans.

Adult↗
PubMed1990

Dyskinetic movements, cognitive impairment, and negative symptoms in elderly neuropsychiatric patients.

The presence or absence of tardive dyskinesia, cognitive status, and psychopathology were assessed in a group of elderly male psychiatric patients (N = 49) in a nursing home setting. Twenty-five patients were found to have tardive dyskinesia, which was associated with a greater degree of cognitive impairment and negative symptoms. This finding was not related to obvious macroscopic organic pathologies, which were less prevalent in the dyskinetic patients. In fact, patients with frontal lesions (primarily lobotomies) had a significantly lower prevalence of tardive dyskinesia.

Aged↗
PubMed1990

The myth of Athena and Arachne: some oedipal and pre-oedipal aspects of creative challenge in women and their implications for the interpretation of Las Meninas by Velazquez.

This paper interprets the myth of Athena and Arachne, as told by Ovid, as a metaphor for mother-daughter conflict. It discusses pre-oedipal and oedipal aspects of the myth with particular focus on creative challenge and artistic competition. A fragment of a clinical case in which the transference exhibited dynamics inherent in the myth is presented. It is proposed that the analyst's knowledge of myth can be helpful in understanding transference manifestations. Finally, Velazquez's Las Meninas is discussed in the light of the myth, which is the subject of the small painting on the back wall above and to the left of the mirror. The author argues that, just as myth can elucidate psychoanalysis, so psychoanalysis can elucidate myth and its inclusion in an artist's iconography.

Aptitude↗
PubMed1989

Phase I clinical and pharmacokinetic study of LY 195448.

LY 195448 is a phenethanolamine that has shown anti-tumour activity in a range of murine tumour models, although its mechanism of action is unknown. Pre-clinical studies have indicated the absence of "standard" side effects such as myelosuppression and gastrointestinal toxicity. The present phase I trial was carried out in nine patients at doses ranging up to 133 mg/m2. The major toxicities up to that dose were mild, reversible hypotension, tachycardia and tremor. No haematological or biochemical toxicity was observed. Murine pharmacokinetics were assessed at a dose level that was effective in experimental tumours and compared with human pharmacokinetic parameters derived from this study. The results indicated the clinical possibility of reaching peak drug levels associated with experimental activity. However, no responses were seen at the doses used. This study was terminated prior to its completion due to an unexplained loss of activity against murine tumours since September 1987. No significant loss of the in vitro anti-mitotic activity originally reported by Boder et al. [3] was observed. Possible reasons for the apparent loss of in vivo activity have been intensively investigated, but no cause has been determined. Therefore, clinical trials with LY 195448 have been discontinued.

Adult↗
PubMed1989

'Air hunger' arising from increased PCO2 in mechanically ventilated quadriplegics.

A number of investigators have proposed that the sense of respiratory discomfort accompanying hypercapnia depends on respiratory mechanoreceptors which inform the sensory cortex of reflex increases in breathing. To test this hypothesis, we studied subjects whose respiratory muscles were paralyzed, and who were thus unable to increase breathing in response to hypercapnia. We gradually elevated inspired PCO2 in four tracheostomized quadriplegic subjects supported by constant mechanical ventilation. These subjects reported sensations of 'air hunger' (e.g., "short of breath", "air-starved") when end-tidal PCO2 increased 10 Torr (mean) above their resting levels. In a second experiment we used the forced-choice technique to determine the ability of three of these subjects to detect repeated changes of end-tidal PCO2. Two detected 7 Torr changes, the third detected 11 Torr changes. These data suggest that changes in breathing are not necessary to evoke the sense of 'air hunger'. We conclude that the likely mechanisms are (1) projection of chemoreceptor afferent traffic to the sensory cortex, and (2) projection of corollary discharge from brainstem respiratory centers to the sensory cortex.

Adult↗
PubMed1989

Identification of blast cells in the peripheral blood of patients with acute leukaemia using the Technicon H-1.

The Technicon H-1 counter represents a refinement of the cytochemistry-based technology of its predecessors, the H6000 and the Hemalog-D. It also has a new channel, the basophil-lobularity channel, which is said to enhance the sensitivity of leukaemic blast detection in comparison with previous instruments. To evaluate this facility, 35 adult patients with acute leukaemia at different phases of their disease were monitored for the presence of circulating leukaemic blasts during a 4-week period. The ability of the H-1 to detect blasts was compared to a careful manual review of a blood and bone marrow smear. Using the latter review as the standard, the sensitivity was 83.8% with a specificity of 78%. Exclusion of patients with severe leucopenia (less than 1.0 x 10(9)/l) increased the specificity to 89%, with little alteration in the sensitivity. We were unable to confirm the high degree of sensitivity claimed in previous reports. The H-1 blast flag, however, would appear useful for screening patients who are off therapy or on maintenance regimens.

Blast Crisis↗
PubMed1989

Synchronization of motor unit firing during different respiratory and postural tasks in human sternocleidomastoid muscle.

1. Motor unit firing has been studied in human sternocleidomastoid muscle. 2. Two needle electrodes were inserted into the muscle and the activity of pairs of motor units recorded during (a) reflex hypercapnic obstructed breathing, (b) eucapnic voluntary copying of (a) against the same inspiratory resistance and (c) voluntary copying of (a) without any resistance, accompanied by isometric neck rotation. 3. Cross-correlation histograms of the firing of unit pairs showed a clear central peak, indicative of synchronization. The mean duration of the peak during voluntary breathing was 25 ms (range 9-40 ms). There was no difference in duration of synchronization during the different tasks. 4. For the duration of the synchronization peak, the mean strength of synchronization expressed as the number of concomitant discharges of the two units as a proportion of the total number of discharges was 0.026 (range 0.011-0.058) for reflex hypercapnic obstructed breathing. For the same unit pairs the strength of synchronization for isometric neck rotation was the same as that during reflex hypercapnic breathing but for voluntary obstructed breathing it was, on average, threefold greater. 5. In three out of twenty-two motor units studied, 'discharge' occurred with an interval of less than 10 ms ('doublet' firing) at the onset of each inspiration during both types of obstructed breathing; this was rarely observed during neck rotation. 6. The results are interpreted in terms of different synaptic drives to the motor units during the three different tasks.

Adult↗
PubMed1989

Nutritional support in the critical care setting (Part 1).

Over the past two decades nutritional support has rapidly become an integral part of the medical care of critically ill patients. As scientific evidence accumulates supporting the important role of underlying nutritional status in determining the eventual outcome of many illnesses, aggressive nutritional intervention has become commonplace in our medical and surgical ICUs. However, nutritional support, particularly parenteral alimentation, is expensive and associated with important morbidity and even mortality. Furthermore, definite evidence of its clinical efficacy under certain specific conditions is often lacking and in need of properly done prospective studies. This review summarizes the basic principles of nutrition as applied to the critically ill patient in the clinical setting. Special emphasis is on practical considerations regarding cost, efficacy (or lack thereof), and potential advantages, disadvantages, and risk of complications of each proposed approach.

Costs and Cost Analysis↗
PubMed1989

Assessment of breathlessness.

In summary, breathlessness is an important symptom in a number of disease states. The most appropriate techniques for assessment of the symptom depend on the circumstances, ranging from the time-honoured clinical interview by a skilled observer, through questionnaires for epidemiological use, to direct scaling of the sensation by subjects under experimental conditions. The use of direct scaling techniques has enabled researching into mechanisms of breathlessness in recent years, resulting in an increased understanding of the sensation, but no significant therapeutic advances as yet. An area of current research interest is study of the different descriptors for the sensation used by different subjects. This may have great practical importance because it may be that, as with pain, different types of breathlessness will respond to different types of treatment.

Dyspnea↗
PubMed1989

[CAS (computer assisted surgery). A new procedure in head and neck surgery].

Computer assisted surgery (CAS) is a new imaging technique designed to assist the head and neck surgeon during surgery. This method is based upon a three-dimensional volume model of the patient's skull generated by computer tomographic imaging procedures such as CT and MR. Body points can be marked in the 3-D model by intra-operative correlation of model and patient using a volume digitizer. Real-time positioning of surgical instruments without visual control can be achieved. The use of the system in surgery of the skull base, orbit and the paranasal sinuses is demonstrated.

Computer Simulation↗