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Biomedical subjects

A Houston

Publications and source records attributed to A Houston.

53 records · Page 3Linked to original sources
PubMed1989

Normal rat serum cytotoxicity against syngeneic oligodendrocytes. Complement activation and attack in the absence of anti-myelin antibodies.

The role of complement in mediating oligodendrocyte and myelin injury has been investigated by studying the effects of normal adult rat serum on syngeneic cultured neonatal glial cells. Rat serum has cytotoxic activity directed against oligodendrocytes but not astrocytes, the potency of which increases with cell maturation. The effects of heat inactivation, decomplemented rat serum, EGTA treatment, removal of any possible anti-myelin antibody by absorption using syngeneic myelin and absence of surface staining for immunoglobulins on serum-treated oligodendrocytes, C9 depletion and reconstitution, and oligodendrocyte staining for surface C9 demonstrate that this cytotoxicity is mediated by complement via antibody independent activation of the classical pathway and is membrane attack complex dependent. These findings significantly extend the previous demonstration of complement activation by extracted myelin, and may have significance for the pathogenesis of demyelinating diseases.

Animals↗
PubMed1989

Normal limits of the high-fidelity pediatric ECG. Preliminary observations.

A study of more than 1,780 neonates, infants, and children was carried out, using a digital electrocardiograph with a sampling rate of 500 per second, to revise the normal limits of the pediatric ECG. The 12-lead ECG was used with V4R replacing V3. All leads were recorded simultaneously off-line in digital form on magnetic tape and were subsequently analyzed using well-established computing techniques. The results showed that the upper 98 percentile limit of normal amplitudes could be up to 46% higher than previously published limits. Differences in some mean values were very much higher, though these are of less clinical significance. In addition, QRS durations were found to be wider than previously published data. Sex-related differences could be demonstrated in both amplitude and duration measurements, particularly in the early adolescent years. This study confirms that to record pediatric ECGs with high fidelity, it is necessary to use equipment that converts the ECG from analog to digital form at a rate of 500 samples/sec. Significant errors in amplitude and duration measurements may be expected if a much lower sampling rate is utilized.

Adolescent↗
PubMed1987

Psychiatric training for primary care residents: proposed standards.

Most of the nation's psychiatric care is provided by primary care physicians, and this trend is expected to continue. Primary care physicians see themselves as poorly trained in psychiatry, and evidence supports a high incidence of missed diagnosis and inadequate or inappropriate treatment. In addition, poor training may underlie the indifference to psychiatric problems often demonstrated by primary physicians. The Ohio Psychiatric Association Foundation has designated an annual award to be given to the primary care program which provides the best psychiatric training in the state, and the psychiatric training directors met to develop criteria for selecting the recipients. The resulting standards emphasize the importance of training which is relevant to a medical care setting, provided by psychiatrists, and supportive of the integration of psychiatric methods into medical care.

Curriculum↗
PubMed1986

The matching law applies to wagtails' foraging in the wild.

Field data concerning the time budgets and foraging success of pied wagtails (Motacilla alba yarrelli, Gould) are reanalyzed. It is found that the data are well described by the generalized matching law, with a marked bias towards spending time on the territory. In this case matching is not the result of maximizing reward rate, but it remains possible that it results from an allocation of time that maximizes survival.

Journal Article↗
PubMed1984

Mitral valve replacement in the first three months of life.

Two infants, aged 2 and 3 months, underwent mitral valve replacement with Björk-Shiley mechanical valves for severe congenital mitral regurgitation not amenable to valve repair. Both infants survived the operation and left hospital taking a low dose aspirin anticoagulant regimen. One child survived for three years without incident, but the other died at 11 months of pneumonia after valve replacement for tissue ingrowth and subsequent thrombosis.

Graft Occlusion, Vascular↗
PubMed1984

A simple separator to generate half micron aqueous particles for lung imaging.

An aerosol of a radionuclide may be used for ventilation imaging as an alternative to radioactive rare gases. For good-quality images as few particles as possible must be deposited in the trachea and bronchi, which means that no, or very few, particles should have aerodynamic diameter of more than 2 micron. We have developed a separator to modify the output of an Acorn jet nebuliser. It reduced the proportion of particles in the aerosol with aerodynamic diameters of more than 2 micron from 60% for the unmodified output of the nebuliser to only 6%; it consisted of a cylinder of perspex with two compartments containing inert spheres, either stainless steel or glass, of diameter 3 mm (the first compartment contained two layers of spheres, and the main section was packed with spheres). To examine the efficiency of the separator system for routine clinical use we compared the images produced and the deposition of the particles in the modified aerosol (using 99TcmDTPA) with the distribution of ventilation of 81Krm in eight subjects. Despite the theoretical differences between the behaviour of a gas molecule and of a particle in the respiratory tree, the images produced using the modified aerosol delivery system were as good as those produced with 81Krm in normal subjects. In abnormal subjects the images produced were only distinguished following the calculation of a penetration index.

Adult↗
PubMed1983

Acute chlormethiazole poisoning in patients notified to the Poisons Unit, Guy's Hospital, 1978--1981.

1 Out of 493 patients with suspected acute chlormethiazole poisoning notified to the Poisons Unit, Guy's Hospital during 1978--1981, the diagnosis was confirmed either analytically or by detailed clinical information in 108 patients, 40 of whom had ingested chlormethiazole alone. 2 The principal signs reported indicate that the clinical features of acute chlormethiazole poisoning resemble those of barbiturate poisoning, with deep coma (n = 66), respiratory depression (n = 26) and hypotension (n = 17) in the severe cases. Five patients died as a result of early, profound respiratory depression. 3 In 53 survivors in whom toxicological analyses were performed, poisoning with chlormethiazole alone had a better prognosis than when ethanol or other drugs were also present, except in patients with hepatic or pulmonary disease or in the elderly. 4 These results emphasise that although patients poisoned with chlormethiazole who survive to reach hospital generally have a good prognosis, fatal respiratory complications often occur before the patient can be treated.

Adolescent↗
PubMedDate not supplied

Vectorcardiograms synthesized from 12-lead ECGs: a new method applied in 1792 healthy children.

The conventional 12-lead electrocardiogram (ECG) is the completely dominating recording technique in electrocardiography despite the superiority of the Frank vectorcardiogram (VCG) in certain situations. In adult cardiology, methods for synthesizing the VCG from the 12-lead ECG have been introduced to improve the interpretation of the 12-lead ECG by permitting VCG analysis in addition. A new method for synthesizing VCGs from 12-lead ECGs is presented and the resulting "12-lead VCGs" compared to Frank VCGs in a group of 21 children. There was good agreement between the two VCG methods. In addition, the "12-lead VCG" was studied in a group of 1792 apparently healthy children. A clockwise inscription of the loop in the horizontal plane was found in less than 1% of children above 1 month of age. The maximal QRS vector in the frontal plane was directed inferiorly and to the left in children older than 1 month of age, while its direction was superior and to the left in only seven children (0.4%). The usefulness of the 12-lead VCG as a tool in ECG interpretation still has to be assessed, but the normal limits presented here represent an important base for further study.

Adolescent↗
PubMedDate not supplied

Susceptibility of nosocomial isolates of Candida species to LY121019 and other antifungal agents.

LY121019 is a novel analog of the polypeptide antifungal antibiotic echinocandin B. We investigated the in vitro activity of LY121019, amphotericin B, ketoconazole and 5-fluorocytosine against 131 nosocomial isolates of Candida species: C. albicans (n = 50), C. tropicalis (n = 30), C. rugosa (n = 12), C. parapsilosis (n = 11), C. lusitaniae (n = 10), C. guillermondii (n = 9), and C. krusei (n = 9). In vitro susceptibility testing was performed using a broth microdilution method. The minimal inhibitory concentrations (MIC) of LY121019 were less than or equal to that of the other antifungal agents against C. albicans and C. tropicalis but were generally higher for the other species of Candida. Paradoxical growth at high concentrations, but not at low concentrations, of LY121019 was observed with isolates of C. albicans and C. tropicalis.

Amphotericin B↗
PubMedDate not supplied

Teen empowerment movement to prevent tobacco use by North Carolina's youth.

Strong youth and adult leadership and exemplary policy and program interventions put a unique synergy to work in North Carolina. The state aspires to be a model for the nation in overcoming barriers related to tobacco use prevention by empowering its greatest resource--youth. New grant funding is building the foundation for youth empowerment programs, and increased and sustained funding is being sought to significantly expand these efforts. Youth speak with a fresh voice, bringing energy and conviction, as well as non-traditional ideas and strategies to the achievement of their goals. By changing public opinion and influencing the actions of leaders in the nation's leading tobacco state, the North Carolina Tobacco Prevention and Control Branch will develop leadership for tobacco use prevention that will serve the entire nation.

Adolescent↗