Biomedical subjects

K A Heller

Publications and source records attributed to K A Heller.

6 recordsLinked to original sources

PubMed1993

Scientific ability.

Following an introductory definition of scientific ability, product-oriented, personality and social psychological approaches to studying scientific ability are examined with reference to competence and performance. Studies in the psychometric versus cognitive psychological paradigms are dealt with in more detail. These two research strategies complement each other excellently in describing and explaining scientific ability and achievement or expertise in the field of science and technology. Whereas psychometric studies seem to be essential for diagnostic and prognostic purposes, cognitive psychological studies help to explain excellent performance. Finally, various possibilities for nurturing scientifically gifted adolescents are discussed, with sex-related problems being touched upon.

Adolescent↗

PubMed1991

Placenta previa percreta involving the urinary bladder: a report of two cases and review of the literature.

The incidences of both placenta previa and placenta accreta are increased in patients with scarred uteri, and patients with uterine scars and placenta previa are at increased risk for also having placenta accreta. Two cases are presented of placenta previa percreta with involvement of the urinary bladder necessitating cesarean hysterectomy, partial cystectomy, and, in one case, bilateral ureteral reimplantation. Both patients had two previous cesarean deliveries. Serious hemorrhage is common in patients with placenta percreta. The primary goal of surgical management must be to control bleeding, which usually requires resection of all tissue involved by the infiltrating placenta. After hemorrhage is controlled, the surgeon must reestablish the integrity of the urinary system and reconstruct the pelvis as necessary.

Adult↗

PubMed1983

Prediction of serous versus purulent otitis media by otoscopy and tympanometry in an animal model.

Non-invasive methods for distinguishing different types of otitis media would have clinical value in predicting otologic morbidity. Two such methods, otoscopy and tympanometry, were used in two experimental models of otitis media to determine whether there are unique otoscopic and tympanometric characteristics of serous and purulent otitis media. A flat (type B or B+) tympanogram and yellow tympanic membrane each had a high likelihood of predicting middle ear effusion in these models, and the best prediction was obtained using both parameters simultaneously. A yellow tympanic membrane color predicted purulent otitis media in one model but did not distinguish purulent from serous ears in the other model. In one model, serous otitis media was frequently associated with a type C (negative pressure) tympanogram. Tympanometry provided a valuable adjunct to otoscopy in detecting effusion and in distinguishing serous and purulent disease. These observations may apply to otitis media in humans, although the variable etiologies of otitis media in humans may confound the ability of otoscopy and tympanometry to distinguish middle ear effusion types.

Acoustic Impedance Tests↗

PubMed1982

Influenza A virus-induced polymorphonuclear leukocyte dysfunction.

Previous studies have shown that influenza A virus can activate the polymorphonuclear leukocyte (PMN) respiratory burst and that upon subsequent stimulation of the cell there is depressed metabolic function. We examined the mechanism by which influenza virus causes PMN dysfunction by measuring the effect upon the chemiluminescent activity of cells of varying the type of influenza virus used, the period of time that cells were exposed to virus, and the secondary stimulus that was used. The various types of intact influenza virus elicited different amounts of chemiluminescent activity, but when cells were subsequently stimulated with phorbol myristate acetate, each virus caused equivalent depression of the PMN response. Purified glycoproteins incorporated into a liposome structure similarly stimulated the PMN chemiluminescence, yet did not induce PMN dysfunction. Depressed PMN function was noted after as little as 5 min of incubation of cells with virus and occurred to both receptor-dependent (zymosan, N-formylmethionyl-leucyl-phenylalanine, and phorbol myristate acetate) and -independent (calcium ionophore A23187) stimuli.

Humans↗

PubMed1982

Inhibition of neutrophil lysosome-phagosome fusion associated with influenza virus infection in vitro. Role in depressed bactericidal activity.

The present study examined the effect of various unopsonized strains of influenza A virus on release of myeloperoxidase (MPO) and acid phosphatase in polymorphonuclear leukocytes (PMNL). These results were correlated with the effect that these same viruses had on bactericidal activity in PMNL. Several strains of virus inhibited the fusion of azurophil granules with phagosomes containing Staphylococcus aureus. These same strains inhibited the extracellular release of MPO from PMNL (39-59%) and caused depressed killing (42-77%). In contrast, one of the influenza viruses (X-47a) did not inhibit PMNL MPO release or killing. The data indicate a close relationship between the ability of influenza virus to ablate normal intracellular lysosome-phagosome fusion with subsequent depression of bactericidal functions of PMNL.

Blood Bactericidal Activity↗

PubMedDate not supplied

Tympanometric configurations and middle ear findings in experimental otitis media.

Relationships between ventilation of the middle ear (ME) system and pathogenic bacteria in the upper respiratory tract were explored in an animal model to better understand the etiopathogenesis of otitis media. Otitis media developed in 12 of 18 chinchillas inoculated intranasally with Streptococcus pneumoniae followed by bilateral ME deflation (negative pressure). Otitis media with effusion developed in 19 of 36 ears examined ten days after inoculation. The development of purulent effusion after ten days was highly correlated with persistent negative ME pressure for at least 48 hours after deflation, while most ears that developed serous effusion after ten days had normal ME pressure 48 hours after deflation. Tympanometric validation of the presence of absence of effusion and type of effusion was obtained ten days after inoculation. A low compliance tympanogram detected 90% of the purulent effusions and was 100% specific for this type of effusion. In contrast. three of four serous effusions were associated with normal pressure/normal compliance tracings suggesting that the physical characteristics or volume of ME effusion and/or the histopathology of the ME cleft are reflected i the tympanometric configuration.

Acoustic Impedance Tests↗