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Biomedical subjects

T Lowe

Publications and source records attributed to T Lowe.

36 records · Page 2Linked to original sources
PubMed1991

Oxygen saturation during third molar removal with local anaesthetic alone and in combination with intravenous sedation.

Oxygen saturation was recorded in 96 adults undergoing removal of third molar teeth in the dental surgery. Half the patients received local anaesthetic alone; the remainder received, in addition, intravenous midazolam. Patients receiving sedation sustained the greatest falls in oxygen saturation. However, in 10 out of 48 patients undergoing third molar removal with LA alone, oxygen saturations in the range of 93-89% were recorded. The results of this study suggest that all patients undergoing removal of third molars are at risk of hypoxia. Short episodes of hypoxia may be of little consequence in healthy patients, but in compromised patients early detection may avoid serious complications.

Adult↗
PubMed1991

Anomalous kinetic visual fields found in family members of patients with a confirmed diagnosis of Gilles de la Tourette syndrome.

Three visual manifestations of Gilles de la Tourette syndrome (TS), a neuropsychiatric disorder, have been previously reported. In this paper we report anomalies in the measured kinetic paracentral visual field of TS patients and their family members. We found that 96% of TS patients exhibited paracentral kinetic visual field defects (nasal and temporal steps, enlargement, "ringing," and/or baring of the blind spot). Ninety-three percent of fathers of TS children and, surprisingly, about 80% of mothers exhibit these characteristic visual field anomalies. Sample data and examples of family studies are reported.

Adolescent↗
PubMed1990

A computer program for selection of oligonucleotide primers for polymerase chain reactions.

We have designed a computer program which rapidly scans nucleic acid sequences to select all possible pairs of oligonucleotides suitable for use as primers to direct efficient DNA amplification by the polymerase chain reaction. This program is based on a set of rules which define in generic terms both the sequence composition of the primers and the amplified region of DNA. These rules (1) enhance primer-to-target sequence hybridization avidity at critical 3'-end extension initiation sites, (2) facilitate attainment of full length extension during the 72 degrees C phase, by minimizing generation of incomplete or nonspecific product and (3) limit primer losses occurring from primer-self or primer-primer homologies. Three examples of primer sets chosen by the program that correctly amplified the target regions starting from RNA are shown. This program should facilitate the rapid selection of effective and specific primers from long gene sequences while providing a flexible choice of various primers to focus study on particular regions of interest.

Algorithms↗
PubMed1990

Breastfeeding: attitudes and knowledge of health professionals.

In this study a questionnaire was used to survey the attitudes towards and knowledge of breastfeeding of 300 health professionals working in Gippsland, Victoria. All groups investigated showed a decrease in knowledge with advancing age and years since training. Female health professionals who reported a positive experience of breastfeeding had a higher average score than those who had never breastfed and those who reported a negative experience of breastfeeding.

Attitude of Health Personnel↗
PubMed1988

Delayed improvement in exercise capacity after cardioversion of atrial fibrillation to sinus rhythm.

In some patients symptoms improve after the restoration of sinus rhythm from atrial fibrillation. To assess the size and mechanism of such change, exercise capacity and pulsed Doppler left ventricular inflow velocities were assessed in 20 patients with established atrial fibrillation. Treadmill exercise capacity was assessed by measuring maximal oxygen consumption and anaerobic threshold before and on day 1 and 28 days after elective DC cardioversion. The relative contribution of atrial contraction to left ventricular filling was determined by relating the maximum height of the A wave to the maximum height of the E wave (A/E) of the Doppler velocity time curve. Cardioversion was successful in 14 patients. Maximal oxygen consumption and anaerobic threshold were unchanged on day 1 and increased by day 28 in all 14 patients. The percentage improvement was inversely related to the baseline values; however, the absolute improvement was small in all patients. The mean A/E ratio increased significantly from day 1 to day 28 in all 14 patients. Thus the restoration of sinus rhythm was associated with a delayed improvement in exercise capacity that may in part be due to a slow improvement in atrial contractility and peak cardiac output after cardioversion.

Aged↗
PubMed1987

Randomised crossover trial of rate responsive Activitrax and conventional fixed rate ventricular pacing.

Atrial tracking pacemakers may improve exercise capacity and symptoms because they maintain atrioventricular synchrony and preserve the physiological response of heart rate to exercise. A rate responsive pacemaker which reacts to physical activity may be effective in patients with sinus node disease who are unsuitable for VDD pacing. At least three months after implant a double blind randomised short and long term crossover study was performed in ten patients with complete heart block: block was present at rest and during exercise on a modified Bruce protocol. Symptoms were assessed on a visual analogue scale and exercise capacity (maximal oxygen consumption and anaerobic threshold) was measured during rate responsive (peak rate 125/min) and conventional fixed rate (VVI) pacing (70/min). One month after randomisation treadmill exercise was performed. The mode was then changed to the other pacing mode and exercise was repeated three hours later. After another month the process was repeated but in the reverse order. During long term assessment there was subjective improvement in the sensation of breathlessness with rate responsive pacing. During short term assessment maximal oxygen consumption increased and the benefit was maintained during long term rate responsive compared with long term VVI pacing; oxygen consumption at the anaerobic threshold was similarly improved. Activity detecting rate responsive pacing is better than fixed rate ventricular pacing in patients with complete atrioventricular block.

Adult↗
PubMed1985

Erythrocyte morphology in women with severe preeclampsia and eclampsia. Preliminary observations with scanning electron microscopy.

Scanning electron microscopy was used to study the morphologic characteristics of erythrocytes in women with preeclampsia and eclampsia. In nine nulliparous women with eclampsia, the proportion of abnormal red cells (schistocytes, echinocytes, and spherocytes) was significantly greater than in 12 normally pregnant control women (p less than 0.001). Likewise, the proportion of these abnormal erythrocyte forms was significantly greater in 12 nulliparous women with preeclampsia than in 25 normally pregnant control women (p = 0.009). Six women with mild pregnancy-induced hypertension without proteinuria were studied before and after magnesium sulfate therapy had been given, and no differences in the proportion of abnormal erythrocyte forms were found. Evidence for microangiopathic hemolysis, manifest by reticulocytosis and thrombocytopenia, was apparent with eclampsia, although only reticulocytosis was identified in women with preeclampsia. There was evidence for hepatic dysfunction in more than half of the women with eclampsia, and in nearly one third of those with preeclampsia. We speculate that compositional changes in the membrane, induced by plasma/erythrocyte lipid interchanges, which are predisposed by normal pregnancy and amplified by severe preeclampsia, especially in the presence of liver dysfunction, may have participated in the genesis of the red cell abnormalities observed. Furthermore, these abnormalities in the cell membrane may increase erythrocyte susceptibility to microangiopathic hemolysis.

Eclampsia↗
PubMed1985

pH profile of the adsorption of nucleotides onto montmorillonite. I. Selected homoionic clays.

The effect of adsorbed ions and pH on the adsorption of several purine and pyrimidine nucleotides on montmorillonite was studied. The cations used to prepare homoionic montmorillonite was Na+, Mn2+, Fe3+, Co2+, Ni+, Cu2+, and Zn2+. The nucleotides studied were 5'-,3'-, and 2'-AMP, and 5'-CMP in the pH range 2 through 12. The results show that preferential adsorption amongst nucleotides and similar molecules is dependent upon pH and the nature of the substituted metal cation in the clay. At neutral pH, it was observed that 5'-AMP was more strongly adsorbed than 2'AMP, 3'-AMP, and 5'-CMP. Cu2+ and Zn2+ clays showed enhanced adsorption of 5'-AMP compared to the other cation clays studied in the pH range 4-8. Below pH 4, the adsorption is attributed to cation and anion exchange adsorption mechanisms: above pH 4, anion exchange may also occur, but the adsorption (when it occurs) likely depends on a complexation mechanism occurring between metal cation in the clay exchange site the biomolecule. It is thus proposed that homoionic clays may have played a significant role in the concentration mechanism of biomonomers in the prebiotic environment, a prerequisite step necessary for the formation of biopolymers in the remaining steps leading to the origin of life.

Adenosine Monophosphate↗
PubMed1985

Human fetal anatomy: MR imaging.

Twenty-four pregnant women carrying 26 fetuses (two sets of twins) were imaged with magnetic resonance (MR) imaging at 0.35 T following sonographic evaluation. Each study was retrospectively evaluated to determine which of 33 normal fetal structures were visible on the images and which imaging parameters were most useful for depicting fetal anatomy. Fetal motion degraded fetal images in all but two cases, both with oligohydramnios and in the third trimester of gestation. Nevertheless, many fetal structures were identifiable, particularly in the third trimester. Visualization of fetal anatomy improved with intravenous maternal sedation in five cases. Relatively T1-weighted images occasionally offered the advantage of less image degradation owing to fetal motion and improved contrast between different fetal structures. More T2 weighting was believed to be advantageous in one case for outlining the fetal head and in one case for delineation of the brain. In many cases, structures were similarly identifiable (though with different signal intensities) regardless of the parameters selected. The authors conclude that MR imaging of many fetal structures is currently unsatisfactory and is probably of limited value, particularly in the first and second trimesters. However, the relative frequency and detail with which the fetal head and liver can be depicted indicate that these may be areas for further investigation, and the potential utility of imaging fetal fat warrants further investigation.

Amniotic Fluid↗
PubMed1980

Gas-chromatographic method of analysis for urinary organic acids. II. Description of the procedure, and its application to diagnosis of patients with organic acidurias.

A gas-chromatographic method for urinary organic acid analysis is described, designed to be used routinely for the diagnosis of organic aciduria. It involves extraction of urine with ethyl acetate, dehydration of extract residues, and trimethylsilylation. Organic acids are identified by using an extensive list of retention indices published in the accompanying paper (this issue). Quantitative values are given for organic acids in urines from 50 ostensibly normal subjects. Typical chromatograms of urinary organic acids from patients with eight well-established organic acidurias are also shown.

Acids↗
PubMedDate not supplied

Adenosinergic modulation of homocysteine-induced seizures in mice.

Homocysteine thiolactone (HTL) elicits seizures in mice at a dose of 850 mg/kg (95-100% of animals) with an average latency time of 19.5 min. These seizures are reversed by both 5' N-ethylcarboximide adenosine (NECA) and flunitrazepam, with respective ED50 doses of 0.025 and 0.20 mg/kg. NECA was approximately four-fold more potent as an inhibitor of HTL-induced seizures than of seizures induced by pentylenetetrazol (PTZ, 75 mg/kg). Flunitrazepam was equipotent in both seizure paradigms. The purine precursor 5-amino-4-imidazole carboxamide riboside, (AICAr), although virtually ineffective against PTZ-induced seizures at doses greater than 1 g/kg, was able to inhibit HTL-induced seizures with an ED50 of approximately 350 mg/kg. The anticonvulsant effect of AICAr was dose and time dependent. The anticonvulsant potency of AICAr was increased by simultaneous administration of the adenosine uptake blocker Mioflazine, whereas the central nervous system (CNS)-impermeable adenosine uptake blocker dipyridamole had no effect. The ability of AICAr to permeate the blood-brain barrier (BBB) is limited (less than 1%) and may explain its low potency as an anticonvulsant. AICAr also has very low potency at brain adenosine A1 and A2 receptors as well as adenosine uptake sites (IC50 greater than 10(-3) M), suggesting that its anticonvulsant properties are not mediated by direct action at these sites. The results indicate that AICAr does have frank anticonvulsant effects and further suggest that HTL-induced seizures may represent a useful paradigm for evaluation of adenosinergic agents. AICAr or more potent derivatives thereof may represent a new class of anticonvulsants with the ability to target seizure foci selectively.

Adenosine↗
PubMedDate not supplied

Aggressive incidents on a psychiatric intensive care unit.

AIM: Although factors related to inpatient aggression have been extensively studied, there is relatively little specific information about violence in intensive care, so the authors decided to conduct their own research into the subject. METHOD: The authors studied the behaviours of the small number of patients who are involved in most of the aggressive incidents in a psychiatric intensive care unit (PICU) over 15 months. RESULTS: The study found that female patients were significantly more likely to be involved in aggressive incidents, but that most of these incidents involved self-harm. Patients with a diagnosis of schizophrenia were more likely to display violent behaviour than those from other diagnostic categories. Patients with a personality disorder were more likely to inflict violence against themselves. CONCLUSION: The authors concluded that all the research on patient violence needs to be standardised to inform practice properly. Nurses need to be aware that relatively few patients are responsible for most of the violent incidents that occur.

Aggression↗
PubMedDate not supplied

Filipino GN to Filipino RN. A well-developed plan leads to success.

This article describes the authors' experience in designing a hospital orientation program for newly recruited Filipino nurses. The nursing department's educational and administrative efforts helped to orient the newly recruited nurses to the hospital and to nursing practice in the United States and prepared them to pass the NCLEX examination. Specific classes included in the orientation are presented. Topic title, time frame, facilitator, components, and rationale for each class are discussed. Suggestions for timing of recruitment and clinical orientation assignments are given. Staff preparation to Philippine culture and nursing practice is also reviewed. The authors believe this information would assist other nursing departments prepare for recruited Filipino nurses on their staff.

Humans↗
PubMedDate not supplied

Metallic postoperative artifacts on cervical MR.

Spectroscopy of cervical diskectomy specimens obtained from sheep demonstrated that metallic susceptibility artifacts are produced by microscopic amounts of nickel, copper, and zinc. Sufficient quantities of metals to produce artifacts are deposited only by contact of metal drill bits and suction tips. If these instruments do not come in contact during surgery, susceptibility artifacts are not observed.

Animals↗