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Biomedical subjects

J D Miller

Publications and source records attributed to J D Miller.

At least 271 records · Page 15Linked to original sources
PubMed1988

Transfusion therapy in emergency medicine.

Volume replacement is critical to the resuscitation of the hemorrhaging patient, but this usually can be accomplished quickly and safely with crystalloid and/or colloid solutions. Red cells should be used in addition to asanguinous fluids in the treatment of tissue hypoxia due to anemia. The need for whole blood as opposed to packed red blood cells is controversial. However, plasma should not be used as a volume expander, and its use to supplement coagulation factors during the massive transfusion of red cells should be guided by laboratory tests that document a coagulopathy. Similarly, platelet transfusions are indicated to correct documented thrombocytopenia or platelet dysfunction, and routine prophylaxis after fixed volumes of red cells results is unwarranted. Many anticipated complications of massive transfusions, including hemostatic abnormalities, acid-base imbalances, hyperkalemia, and hypocalcemia, are uncommon or of limited clinical significance. The risks of immune hemolysis and transfusion-transmitted diseases, on the other hand, are significant, and argue for judicious use of blood components. In emergencies in which blood is required immediately before compatibility testing can be completed, O-negative uncrossmatched blood can be requested. Careful blood specimen collection and patient identification prior to transfusion are critical. Practices that emphasize blood conservation, including the use of autologous salvaged blood, are always to the patient's advantage.

Blood Grouping and Crossmatching↗
PubMed1988

Elevated cerebellar glucose metabolism in microvascular white matter disease: normal aging and Alzheimer's disease.

Young normal, elderly, and clinically diagnosed Alzheimer disease subjects who had undergone positron emission tomography (PET) and computed tomography (CT) examinations were studied to determine the effect of periventricular white matter lesions on cerebellar glucose metabolic rates. PET-determined cerebellar metabolic rates were elevated in subjects with periventricular white matter lesions. These results suggest the cautious use of cortical-to-cerebellar ratios in future PET or single-photon-emission CT (SPECT) studies.

Adult↗
PubMed1988

Other potential clinical uses of oral rehydration.

An increasing awareness that bowel absorptive function can be maintained or returned to normal soon after trauma or abdominal injury and the formulation of glucose/electrolyte solutions specifically designed to be rapidly absorbed from the small bowel are responsible for the current trend of early oral rehydration and decreasing use of intravenous fluids in surgical patients. Much of this article is devoted to observations and results of clinical trials on surgical patients in Aberdeen Royal Infirmary and Dr Gray's Hospital, Elgin. To date, the results of early oral rehydration after surgery have been sufficiently encouraging to create changes in the routine fluid resuscitation and management protocols in several areas of surgical practice at these centres.

Adolescent↗
PubMed1988

Epidermal growth factor binding in intracranial neoplasms: preliminary biochemical and clinicopathological findings.

The binding capacity for epidermal growth factor (EGF) was determined in 34 intracranial neoplasms (14 glioblastoma, seven low-grade gliomas, six meningiomas, and seven others) and four specimens of normal brain by using [I125]EGF. EGF binding and binding affinity of the sites in the tumour and brain samples were compared to placenta and rat liver. All specimens of normal brain were negative. Ten of 14 glioblastoma specimens contained EGF binding (level range 10-39,660 fmol/mg protein), however, ligand binding affinity was high in only three tumours. Only one of nine low-grade gliomas contained EGF binding activity. Five of six meningiomas contained EGF binding sites (level range 49-776 fmol/mg protein) and binding affinity was high in two. When present EGF binding activity was found in all cellular fractions except the cytosol. There were no clinical or histopathological features within major tumour groups that were predictive of either high or specific EGF binding activity. These preliminary studies have confirmed that EGF receptor-like activity is present in the particulate fractions of intracranial neoplasms of both mesenchymal and neuroctodermal origin. In a large proportion of these tumours the EGF binding affinity is low, suggesting either a less specific or truncated EGF binding site.

Brain Neoplasms↗
PubMed1988

Head injury rehabilitation: 4 years' experience in Edinburgh.

A survey was done of all cases of head injury admitted to a neurorehabilitation unit which, while mainly servicing the regional acute head injury unit, receives patients from throughout Scotland. During the 4 calendar years 1983-1986, 183 new cases of head injury were treated. The patients were predominantly young adult males the great majority of whom had suffered severe head injuries. Most were directly transferred from neurosurgical units within 6 months of injury. The length of stay in the unit varied from less than 1 month for half of the patients to as long as 10 months. Eighty-four per cent of patients were discharged home. The limitations and constraints upon the service are described and the need for a rational approach to the development of head injury rehabilitation facilities in the United Kingdom are discussed.

Adolescent↗
PubMed1988

Information explosion in radiology.

We studied the increase in the number of articles in the radiologic literature in the years 1970, 1978, and 1985 using the Medlars program which provides reproducibility, a recognized bibliographic pool, and a wide coverage of the medical literature. A dramatic increase in the number of articles was found; the increase has both positive and negative implications for the profession. A similar analysis of monographs using the Catline file and the same subject headings also showed a significant increase in the volume of material relating to certain radiologic subspecialties. The problems arising from the attempt to identify and extract relevant information from this overwhelming mass of radiological data should be addressed.

Books↗
PubMed1988

Cardiovascular effects of fentanyl reversal by naloxone at varying arterial carbon dioxide tensions in dogs.

Clinical reports, as well as animal studies, have described cardiovascular and sympathetic stimulation after the administration of naloxone (NX) to reverse opioid-induced respiratory depression. This investigation examines the effect of PaCO2 on hemodynamic and adrenergic responses to NX, by means of 24 experiments carried out in six dogs. Each dog underwent NX reversal of fentanyl (FEN) at three different PaCO2 levels: 20, 35, and 60 mm Hg. In a final series of six experiments, the dogs were exposed to increasing PaCO2 after autonomic block by total spinal anesthesia and vagotomy. During enflurane anesthesia, 50 micrograms/kg FEN decreased mean arterial blood pressure (MAP), heart rate (HR), and plasma concentrations of norepinephrine (NE) and epinephrine (EPI) significantly. NX 0.4 mg promptly returned HR and MAP to baseline or above in all experiments; catecholamine (CA) levels increased only in hypercapnic dogs. Increases in HR were the same in all series. MAP, EPI, and NE levels were significantly greater than pre-FEN baseline values only in hypercapnic dogs 1 minute after NX and were also significantly higher in hypercapnic than in hypocapnic dogs at this time. NE levels were greater in hypercapnic dogs at all time periods after NX. In blocked dogs, neither F nor NX had any effects on hemodynamic functions or plasma CA levels; the institution of hypercapnia caused significant decreases in HR, MAP, and systemic vascular resistance. This direct circulatory depressant action of an elevated PCO2 may have attenuated the indirectly mediated excitatory hemodynamic effects of NX in intact dogs, thus explaining the relatively greater effect of hypercapnia on adrenergic than on hemodynamic responses to reversal.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

The anti-emetic properties of 1-sulpiride in a ground-based model of space motion sickness.

L-sulpiride, at a dose of 4 mg/kg, essentially abolished motion-induced emesis in a group of 6 squirrel monkeys undergoing horizontal rotation at 25 rpm, a terrestrial model of space motion sickness (SMS). Extrapyramidal side effects were not observed. In the absence of the drug, the usual emetic response returned. In comparison while typical neuroleptics were also strongly anti-emetic, they produced a considerable degree of rigidity and akinesia.

Animals↗
PubMed1987

The binding of Ca2+ to Ca2+-transporting microsomes derived from bovine uterine sarcoplasmic reticulum.

An obligatory early step in the transport of calcium across the internal membranes of smooth muscle cells is the binding of calcium to the Ca,Mg-ATPase. The characterization of calcium binding to sarcoplasmic reticulum from smooth muscle has not been reported. Calcium binding to a bovine myometrium preparation was investigated using Scatchard analysis and a computer program utilizing weighted least squares curve fitting and an exact mathematical model of binding. This permitted objective measurement of goodness of fit and showed that best fit was obtained using a two site model. Magnesium did not change the affinity for calcium of the two sites; but reduced the number of low affinity sites to half.

Animals↗
PubMed1987

What follows diagnosis by computed tomography of solitary brain tumour? Audit of one year's experience in South East Scotland.

The referral rate to neurosurgeons after diagnosis by computed tomography (CT) of solitary brain tumour (SBT) was audited for South East Scotland in 1985. 142 patients had SBT diagnosed by CT, but histological confirmation by biopsy or open operation was sought in only 67. Among these the CT diagnosis of glioma proved to be incorrect in 3 of 44 cases and that of solitary metastasis in 4 of 8 cases. Since CT diagnosis of SBT is not fully reliable, biopsy should be considered in all cases.

Adult↗
PubMed1987

Clinical usefulness of the palmomental reflex.

The palmomental reflex was elicited, unilaterally or bilaterally, in 28% of a series of 121 patients with neurological disorders. There was no significant variation in the prevalence of the palmomental reflex with the age and the sex of patients, with the cause of the neurological disorder, or with the site of cerebral lesions. However, the reflex was found to be significantly more common among patients with signs of focal or generalized brain dysfunction than among patients with normal cerebral function (P less than 0.001). The side of the body on which the reflex was elicited was no indication of the side on which the cerebral lesion was situated. In three patients, who were examined on several occasions, the reflex disappeared as the psychomotor function of the patients improved. On the basis of the results, the nature of the palmomental reflex and the reasons why its presence is difficult to interpret are discussed.

Adult↗
PubMed1987

Brain water measured by magnetic resonance imaging. Correlation with direct estimation and changes after mannitol and dexamethasone.

Brain water content was measured in tissue samples taken at operation from 19 patients with intrinsic cerebral tumours imaged preoperatively by magnetic resonance. A high correlation (r = 0.94, p less than 0.0001) between white matter water content and the longitudinal relaxation time (T1) enabled water content to be estimated from T1 to within 4%. 11 patients received dexamethasone and improved clinically but their T1, and thus brain water content, was unchanged an average of 6 days later. Intravenous infusion of 20% mannitol in 11 patients significantly reduced T1 in oedematous white matter and tumour within 15 min of administration, and by 30 min the T1 of oedematous white matter had fallen to a mean of 32.4 (SEM 7.1) ms, corresponding to a reduction in water content of 1.4 (0.3)%.

Adult↗
PubMed1987

ICP monitoring--current status and future directions.

Continuous monitoring of intracranial pressure (ICP) is now an accepted part of neurosurgical practice, used in the management of patients with severe head injury, coma-producing subarachnoid haemorrhage, hydrocephalus, intracranial infection and following hypoxic or ischaemic insults to the brain. The pressure is measured from the lateral ventricle or from the subarachnoid space, and each neurosurgical department should establish criteria for determining what level of increased ICP should be acted upon and how it should be managed. This review favours a three stage approach: a) determining that ICP is truly elevated and correcting any immediately remediable causes, such as airway obstruction, then b) first-line measures, which consist of hyperventilation, osmotherapy and controlled CSF drainage, then c) second-line measures, consisting of short-acting anaesthetic agents--thiopentone and gammahydroxybutyrate. Future refinements of ICP monitoring will include improved understanding and better methods of measuring intracranial pressure-volume relationships and more detailed analysis of intracranial pulse pressure and the pressure waveform, its changes with mean ICP and its relationship with the arterial pressure waveform.

Biomechanical Phenomena↗
PubMed1987

CT guided functional stereotaxic surgery.

One of the major problems in stereotaxic surgery is to identify the brain target. Since these do not show on any of the usual radiological studies they have to be located with reference to observable structures. Initially bony landmarks were used but later either positive or negative contrast ventriculograms were found to be more accurate. Often this involves additional needling of the brain or a spinal puncture with the added mortality and morbidity associated with these procedures. We have extended the use of CT guided stereotaxic surgery to functional conditions by measuring the target position in relation to the third ventricle and the AC-PC line as seen on the unaugmented CT scan. Our experience with 27 procedures in 23 patients (9 movement disorders, 13 pain and 1 insertion of depth electrode) would indicate it is at least as accurate as other techniques. The surgical time is usually shorter and patient tolerance is better.

Adult↗
PubMed1987

A new look at uterine muscle contraction.

Recent progress in our understanding of uterine smooth muscle contraction is reviewed. We no longer believe that actin-myosin interaction in the myometrium occurs through activation of the thin filament; but it is triggered by calcium-dependent phosphorylation of myosin in the thick filament. Calcium is now thought to originate from both extracellular and intracellular sources. Calcium can enter the cell through either a voltage- or a hormone-controlled calcium channel. The intracellular source of calcium is the sarcoplasmic reticulum. The effect of oxytocin in human labor is no longer considered the result of increased circulating oxytocin but rather of increased oxytocin receptors. In contrast, the contractile action of some prostaglandins is related to increased prostaglandin formation at human parturition. The step between hormone binding and cellular action is mediated by second messengers. The uterine-relaxing action of cyclic adenosine monophosphate is now thought to be limited to the inhibition of myosin phosphorylation. Recently discovered second messengers for contraction of the myometrium are phosphoinositides; their turnover causes calcium release from the sarcoplasmic reticulum. Guanine nucleotides are thought to be modulators of these two second messengers.

Adenosine Triphosphatases↗
PubMed1987

The effects of dialysis on brain water and EEG in stable chronic uremia.

Cerebral edema in uremic animals and humans, as well as an EEG deterioration in humans, has been reported after dialysis. Both are manifestations of the dialysis disequilibrium syndrome (DDS). This study was designed to analyze the changes induced by dialysis in the EEG pattern (spectral analysis), in the cerebral hydration, and ventricular size (computed tomography [CT] of the brain) in a group of 11 stable uremic patients. They volunteered for a randomized crossover study of 4 months each of standard hemodialysis (HD) and hypertonic hemodiafiltration (H HDF). H HDF is a dialysis technique that is shorter and more efficient than HD. An EEG recording, a CT scan of the brain, and blood biochemistry were performed before and after a HD (four hours, blood flow rate 250 mL/min) and a H HDF run (three hours, blood flow rate 400 mL/min). Approximately 6 weeks of stabilization on each treatment were allowed before these studies. No difference was found in the density of seven specific brain structures (base and apical cuts), when comparing pre- v post-HD, pre- v post-H HDF, pre- HD v pre-H HDF, and post-HD v post-H HDF. Furthermore, no difference was evident either in the bicaudate diameter of the lateral ventricles or in the transverse diameter of the third ventricle. In addition, no significant in-between- and within-treatment difference was observed when analyzing the EEG% power (3-7/7-13 Hz) data. In conclusion, this study shows neither a postdialysis change in brain density and ventricular size nor a postdialysis EEG deterioration in a group of stable uremic patients undergoing both a rapid and a standard dialysis treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗