Biomedical subjects

R Milroy

Publications and source records attributed to R Milroy.

58 records · Page 4Linked to original sources

PubMed1978

Amplitude-modulated noise: the detection of modulation versus the detection of modulation rate.

Modulation threshold, that is, the modulation depth required to discriminate a sample of amplitude-modulated (AM) noise from a sample of unmodulated noise, was measured as a function of modulation rate (16--320 Hz), modulator waveform (sine or square), and the bandwidth of the AM noise (0.5--8.0 kHz). Modulation threshold increases monotonically with modulation rate, sine-wave thresholds are greater than square-wave thresholds, and threshold rises as the bandwith of the AM stimulus decreases. These effects all support the use of some form of energy detection model to explain modulation threshold. The modulation thresholds were compared with pitch thresholds gathered under precisely the same conditions. Pitch threshold or, alternatively, rate threshold was taken to be the modulation depth required to decide which of two samples had the higher modulation; the rate difference was 20%--just over three semitones. In the region above about 70 Hz, rate threshold is essentially a constant multiple of modulation threshold, indicating that the primary constraint on rate threshold is the audibility of the modulation. Below 70 Hz, rate and modulation threshold diverge; it is argued that the limit on rate threshold in this region is probably the length of the correlation required to extract the periodicity.

Adult↗

PubMedDate not supplied

Quality of life in lung cancer patients: as an important prognostic factor.

Given that lung cancer is one of the common cancers world-wide, the implications of focusing on quality of life as well as survival require to be understood. We have carried out a study of the relationship between survival and quality of life in patients with lung cancer comparing patients those who lived with those who died within 3 months. The design of the study allowed every patient in a defined geographical area with a potential diagnosis of lung cancer to be studied from first outpatient consultation till after a definitive treatment has been given. Quality of life was measured using three standard questionnaires: the Nottingham Health Profile (NHP), the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) and its lung cancer supplementary questionnaire (QLQ-LC13) in addition to a study specific questionnaire collecting data on demographic, social, clinical and performance status. The contribution of quality of life in relation to survival adjusted for known prognostic factors was determined using Cox's proportional hazard model. In all 129 lung cancer patients were interviewed, and 96 patients were alive at 3-months follow-up. Only 90 of 96 patients alive at 3-months follow-up were assessable. Descriptive analyses showed that those who were dead had more perceived health problems, greater level of symptoms and significant lower physical and role functioning and global quality of life at presentation. On the other hand, univariate analyses showed that patients' aggregate scores on the NHP, the functioning scores, and global quality of life scores alone were significant predictors of survival (P<0.03, P<0.04, P<0.04, respectively ). The multivariate analyses showed that pre-diagnosis global quality of life was the most significant predictor of the length of survival even after adjusting for known prognostic factors (age, P<0.04; extent of disease, P<0.03; global quality of life, P<0.02), while performance status, sex and weight loss were not. This study confirmed that pre-diagnosis quality of life was a significant predictor of survival. Indeed, pre-diagnosis quality of life should be considered as a clinical status which has to be established by physicians before treatment starts as it is such an important predictor of survival.

Adult↗

PubMedDate not supplied

Lack of expression of P-glycoprotein in 7 small cell lung cancer cell lines established both from untreated and from treated patients.

The establishment and characterisation of 7 small cell lung cancer cell lines is described. Four cell lines were established from biopsies taken from untreated patients and one of these was from primary tumour taken via the fibreoptic bronchoscope. The other three were from biopsies taken from patients who had relapsed after chemotherapy. All grow as non-adherent aggregates of cell and express a range of neuroendocrine and epithelial features characteristics of small cell lung cancer cell lines. No relationship was observed between the characteristics of the cell line in vitro and the treatment status of the patient from whom the biopsy was taken. Furthermore, none of the cell lines expressed p-glycoprotein even though 3 were derived from relapse biopsies where chemotherapy included drugs associated with the multidrug resistance phenotype.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

In vitro formation of a toxic aglycone metabolite of 4-demethoxydaunorubicin in conditions that parallel the stomach.

4-Demethoxydaunorubicin is a new anthracycline anticancer drug administered orally to cancer patients. In vitro chemical stability has been studied in conditions that parallel the stomach (pH 1, dark, 37 degrees C) by HPLC. The drug was converted to its aglycone form at a rate of 3% (total starting amount) per hour. Thus, after only 3 to 4 hours significant aglycone formation had occurred (greater than 10%). The aglycone was detected to be present in patient urine in significant amount. Anthracycline aglycones lack cytotoxicity but retain toxic potential to host tissues. Formation in vivo in the stomach would result in a reduction in the therapeutic index of the drug.

Chromatography, High Pressure Liquid↗