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Biomedical subjects

P Howell

Publications and source records attributed to P Howell.

At least 73 records · Page 4Linked to original sources
PubMed1981

Automated screening of antenatal samples using a low ionic strength polybrene system.

The use of a two-channel AutoAnalyzer II system in the routine screening of antenatal sera is described. A low ionic strength polybrene method has been used to give optimum detection of IgG antibodies, and hence the system provides a valuable early detection of such antibodies in pregnancy. Of 88 Rhesus antibodies initially detected on the AutoAnalyzer only and followed up later in pregnancy, 18 (20.45%) were later detected by manual methods and were considered to be of potential clinical significance, whilst the remainder were detectable by the AutoAnalyzer only and occurred with a similar frequency as AutoAnalyzer only Rh antibodies in non-immunized males. The sensitivity of the method can provide interpretational difficulties, revealing many apparent "non-specific' reactions as well as detecting low levels of specific antibodies of debatable clinical significance. An approach to dealing with these problems without compromising the benefits of the system is discussed.

Antibodies↗
PubMed1980

Isotonic vocalis contraction as a means of producing rapid decreases in Fo.

In a first experiment, subjects were presented with frequency modulated tones and instructed to vary their own vocal pitch to match what they were hearing. It was found that the faster a subject modulated his voice, the higher the carrier frequency he produced became relative to that specified as his target. In a second experiment, subjects were presented with one or two target tones. After one was presented, they were required to reproduce its pitch with their own voice. They did so accurately. After two were presented, they were asked to oscillate the pitch of their voice as rapidly as possible between them. In this case, it was found that the tones which were produced were higher than those specified by the targets. It is argued that the results from both experiments indicate that fast decreases in voice pitch are produced by isotonic contraction of the vocalis muscles.

Adult↗
PubMed1976

The rare blood group antigen, Wu.

The inheritance of the Wu antigen in three families is described. The observations suggest that the antigen is inherited as a Mendelian dominant character. Wu segregates independently of sex and of the ABO, MNSs, Rh, Lutheran, Duffy and Kidd blood group systems. Independence of Kell is also quite likely. Wu is a very rare antigen. The corresponding antibody is not as infrequent. Anti-Wu occurs as a 'naturally occurring' antibody, often together with antibodies against other rare antigens.

Blood Group Antigens↗
PubMed1969

Haemolytic disease of the newborn caused by anti-Lan antibody.

The first recorded example of anti-Lan associated with haemolytic disease of the newborn is reported. This emphasizes the importance of screening for atypical antibodies early in pregnancy, even though prophylactic use of anti-D immunoglobulin will eventually reduce the incidence of haemolytic disease due to anti-D antibody.

Adult↗
PubMedDate not supplied

Oxaprozin cross-reactivity in three commercial immunoassays for benzodiazepines in urine.

Immunoassay methods are commonly used to screen for drugs of abuse and some prescription drug classes as part of drug-testing programs in clinical and forensic toxicology. Oxaprozin (Daypro) is a new nonsteroidal anti-inflammatory drug that is widely prescribed in North America and has been reported to cross-react for benzodiazepines in several different immunoassay methods. The first objective of this study was to characterize the immunoreactivity of oxaprozin standards over a wide concentration range when analyzed by the EMIT dau, Abbott FPIA, and BMC CEDIA urine benzodiazepine assays. The second objective was to measure the immunoreactivity of urine specimens obtained from 12 subjects after receiving a single oral dose (1200 mg) of oxaprozin. Urine oxaprozin standards were prepared in drug-free urine at seven concentrations ranging from 500 to 100,000 ng/mL. The standards gave presumptive positive benzodiazepine results between 5000 and 10,000 ng/mL (EMIT dau) and approximately 10,000 ng/mL (FPIA, CEDIA). With a 200-ng/mL cutoff for benzodiazepines in these assays, all 36 urine specimens collected from the 12 subjects gave positive results by EMIT and CEDIA, and 35 of 36 urine specimens were positive by FPIA. It was concluded that presumptive positive benzodiazepine results by these immunoassays may be due to the presence of oxaprozin or oxaprozin metabolites. It is recommended that all positive immunoassay screening tests for benzodiazepines be confirmed by another technique based upon a different principle of analysis.

Administration, Oral↗
PubMedDate not supplied

Relationship of pain to the radiological anatomy of the hip joint in adults treated for congenital dislocation of the hip as infants: a long-term follow-up of patients treated by three methods.

Sixty female patients with congenital dislocation of the hip treated by three methods were followed up to a mean age of 27.3 years. Standard radiographic measurements of hip joint morphology, including stereoscopic measurements of acetabular and femoral neck anteversion, were made. The Severin score of the hip joint, but not acetabular or femoral neck anteversion, was related to symptoms. Hips treated by femoral derotation osteotomy had superior results to hips treated by traction reduction alone. Both of these methods gave much better results than treatment by closed manipulative reduction. The "normal" opposite hip was morphologically abnormal, although usually asymptomatic.

Female↗
PubMedDate not supplied

Perceptual and acoustic evidence for reduced fluency in the vicinity of stuttering episodes.

A perceptual experiment and acoustic analyses were conducted to address the question whether stuttering occurs only at specific "moments" or whether it also affects the surrounding speech. Sections of stutterers' speech were extracted from clauses which were spoken completely fluently (control) or contained one stutter (experimental). In the experimental sections, only speech up to or following the stuttered word was employed. All sections were rated by independent groups of subjects for fluency, the nature of the excised stutter (repetition or prolongation), and the temporal position of the stutter relative to the fluent section that they heard (before or after). Two additional groups of listeners were asked to select from experimental-control pairs the section that had been drawn from near a stutter, and to indicate type and position of the stutter. Listeners could reliably judge which sections had been near a stutter and the type of that stutter, but not its position. Acoustic analyses showed that there were no differences in duration, rate, number of pauses, and average intensity between the experimental and control sections. However, there were significant differences in terms of the drop in intensity between the syllables in the respective sections. The perceptual identification of experimental versus control sections showed a significant relationship with this acoustic measure and with speech rate. The judgments about the type of stutter only correlated with drop in intensity. We conclude that stuttering episodes affect the intensity-time profile of the speech in their vicinity, and that listeners can use this acoustic information to infer the presence and type of the stutter.

Humans↗