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Biomedical subjects

C G Fowler

Publications and source records attributed to C G Fowler.

At least 55 records · Page 3Linked to original sources
PubMed1989

The bifrequency binaural interaction component of the auditory brainstem response.

The binaural interaction component of the auditory brainstem response was investigated in three stimulus conditions, 1000-Hz tone pips to both ears, 3000-Hz tone pips to both ears, and 1000-Hz tone pips to the left ear and 3000-Hz tone pips to the right ear. A binaural interaction component was produced in all conditions in which the stimuli were presented in quiet and in broadband noise, suggesting that a frequency separation of 2000 Hz between ears can produce a fused image. Responses to the bifrequency stimuli in noise indicated the peak A of the binaural interaction component is not dependent solely on the slope of wave V because when the noise caused a dissociated binaural wave V, peak A was associated only with the trailing wave V.

Acoustic Stimulation↗
PubMed1989

Transitional cell carcinoma of the renal pelvis and ureter.

In a retrospective study of 185 patients with transitional cell carcinoma of the renal pelvis and ureter, of whom 127 were treated by total nephroureterectomy and 58 by conservative resection, the survival of those with superficial well differentiated tumours was greater than 90% in each group. When urothelium was left behind after conservative resection, there was a 22% rate of recurrence on the same side but this almost only occurred when the original tumour had been multifocal. Post-operative radiotherapy did not improve survival.

Adult↗
PubMed1989

The fate of G3pT1 bladder cancer.

Poorly differentiated (G3) cancers are known to have a worse prognosis than other superficial bladder tumours. In the period 1976 to 1987, 53 patients with G3pT1 disease were treated by radical radiotherapy with a 5-year survival rate of 64%. Thirteen patients (25%) developed an invasive tumour during the follow-up period. The presence of secondary carcinoma in situ was associated with a poor prognosis. These results are better than those reported for transurethral resection alone and suggest that radiotherapy is the treatment of choice in G3 superficial tumours.

Adult↗
PubMed1989

The 40-Hz potential and SN10 as measures of low-frequency thresholds.

This study investigated the accuracy of threshold estimates using the 40-Hz Potential and the SN10 in the presence of elevated low-frequency thresholds. In Experiment 1, subjects with normal hearing were evaluated with ipsilateral low-pass masking to elevate low-frequency thresholds and in Experiment 2, subjects with low-frequency sensory hearing losses were evaluated. The stimuli were 500-, 1500-, and 3,000-Hz tone pips. The 40-Hz Potential and the SN10 were equally good predictors of the behavioral threshold when the low-frequency, pure-tone thresholds were elevated.

Adult↗
PubMed1989

Urothelial malignancy.

Urothelial malignancy fascinates the urologist by the range of problems it presents. In superficial bladder cancer, we have reduced the demands of treatment by using fibrescopic technology to make outpatient treatment comfortable and acceptable to our patients. We have adopted a policy of radiotherapy and salvage cystectomy to try to preserve bladder and sexual function in our patients with invasive bladder cancer. The results of recent histological studies may help us to predict which patients will respond to radiotherapy so that we can offer alternative treatment to those who will not. At present, the endoscopic management of tumours of the upper urinary tract poses technical difficulties which will resolved only after further advances in technique and instrumentation.

Carcinoma, Transitional Cell↗
PubMed1988

Low-frequency activity in the binaural interaction component of the auditory brain stem response.

The purpose of this study were to determine (1) the contribution of low-frequency activity in the auditory brain stem response (ABR) to the binaural interaction component, and (2) an optimal set of parameters for recording the binaural interaction component. ABRs were recorded from 12 adult subjects with normal hearing using 1000 Hz tone pips at three stimulation rates (10, 25, and 50/sec) and two physiological filters (150-3000 and 30-3000 Hz). The latencies of wave V in the sum of the left and right monaural responses [V(L + R)] were shorter with the 150 to 3000 Hz filter than with the 30 to 3000 Hz filter, whereas the amplitudes of V(L + R) and peak A of the binaural interaction component were similar. The amplitudes of V(L + R) and A were larger for 50/sec than for 10 or 25/sec, but the amplitude ratio of peak A to wave V(L + R) was not different. In conclusion, (1) the activity between 30 to 150 Hz did not enhance the binaural interaction component, and (2) the largest and most reliable binaural interaction component was recorded with a rate of 50/sec and a filter setting of 150 to 3000 Hz.

Acoustic Stimulation↗
PubMed1988

Reappraisal of the role of radical radiotherapy and salvage cystectomy in the treatment of invasive (T2/T3) bladder cancer.

One hundred and eighty-two patients with invasive (T2/T3) bladder cancer were treated by radical radiotherapy at the London Hospital between 1974 and December 1985. Cystectomy was reserved for patients whose tumours either did not respond completely to radiation or recurred later, provided they were fit for surgery and had not developed distant metastases. The overall corrected 5-year survival rate was 40%; 75 patients responded to radiation and did not relapse during the period of follow-up; 20 patients had an initial response to radiation but subsequently relapsed, with a 5-year survival rate following relapse of 20%. Of these, 11 patients had a cystectomy with a 5-year survival following relapse of 36%, whereas all 9 patients who did not have a cystectomy died within 3 years; 87 patients who did not respond to radiation had a 5-year survival rate of 18%. Of these, 22 patients underwent salvage cystectomy with a 5-year survival of 47%, whereas the 65 patients who did not have a cystectomy had a 5-year survival of 3%. These results justify a policy of radical radiotherapy and salvage cystectomy rather than elective cystectomy in the treatment of invasive bladder cancer.

Adult↗
PubMed1988

Chemotherapy for carcinoma in situ of the bladder.

In an 8-year period, 71 patients were diagnosed as having carcinoma in situ of the bladder. Twenty patients with primary carcinoma in situ were treated with systemic cyclophosphamide or intravesical mitomycin C and 19 of them survived 3 years. Three patients required cystectomy: 1 for invasive cancer and 2 for intractable symptoms in the absence of tumour. Fifty-one patients had either secondary or concomitant carcinoma in situ. Systemic or intravesical chemotherapy was given to 28 patients in whom carcinoma in situ was associated with G1 or G2 exophytic superficial tumour: there was only one cancer death in 3 years. Fifteen patients with G3 carcinoma in situ associated with a G3 or invasive exophytic tumour were treated with radiotherapy: 9 responded but 4 of the 6 with radio-insensitive tumours died of cancer within 3 years. Eight patients with secondary carcinoma in situ were managed by transurethral resection alone: in 6 there was spontaneous regression and 2 developed muscle invasion within 1 year. These results compare well with those of immunotherapy or early radical surgery and suggest that chemotherapy should be given a trial in patients with carcinoma in situ.

Administration, Intravesical↗
PubMed1988

Validation of addition and subtraction of ABR waveforms.

Procedures that use the auditory brainstem response (ABR) to demonstrate binaural interaction, phasic differences, narrow-band derived responses, and adaptation rely on additions and subtractions of waveforms to demonstrate effects that are not evident in the raw waveforms. The purpose of this study was to validate these data manipulations by performing additions and subtractions of waveforms in cases in which the theoretical result should be no difference potential and in cases in which the theoretical result should be a difference potential. The results indicate that additions and subtractions of ABR waveforms are valid data manipulations.

Adult↗
PubMed1987

Early repair of accidental injury to the ureter or bladder following gynaecological surgery.

Operative injury to the ureter or bladder in 59 women who had received no previous pelvic radiotherapy was repaired as soon as possible after referral. In 32, this was less than 6 weeks from the injury, while in 27 patients the delay in referral was greater than 6 weeks. Ureteric injuries in 40 patients (43 ureters) were repaired by the Boari-Ockerblad technique. Post-operative vesicovaginal fistulae in 19 women were repaired transvesically with an omental patch. Primary healing was obtained in all cases whether early or late. These results support our recommendation for early intervention in these injuries.

Female↗
PubMed1986

Effects of signal duration on the 500-Hz masking-level difference.

Two experiments were conducted to study the masking-level difference (SoNo-S pi No thresholds) for 2-128-ms, 500-Hz tones in 32-dB pressure-spectrum level, continuous broadband noise. In Experiment 1 (N = 8) the Békésy tracking procedure was used, whereas in Experiment 2 (N = 3) an adaptive, two-interval forced-choice (2IFC) psychophysical procedure was used. The data from both experiments indicated that as the signal duration was shortened from greater than or equal to 100 to approximately 10 ms the SoNo and S pi No threshold integration functions diverged, thereby producing an increase in the masking-level difference. For signal durations less than 10 ms, however, the SoNo and S pi No threshold functions converged and the masking-level difference decreased. In Experiment 2, the mean masking-level difference decreased significantly by 1.7 dB as the signal duration was shortened from 10 to 2 ms. This new finding, which was not anticipated, has recently been confirmed in another laboratory (Cokely & Hall, 1985).

Acoustic Stimulation↗
PubMed1985

DNA content of human semen--an objective measurement of sperm density.

In this study we have adapted a well tried and sensitive fluorometric assay for DNA that uses m-diamino benzoic acid (DABA) for its reaction with deoxyribose which is cleaved by perchloric acid from DNA. We have confirmed that this is easily measured in human semen. The method has been used on 200 samples of semen from patients attending the Infertility Clinic and men attending before and after vasectomy to give a wide range of sperm density. The objective DNA estimation has been compared with sperm density measurement made by an experienced laboratory observer using the Makler chamber and making his observations in ignorance of the DNA estimations. There was good correlation between DNA concentration and sperm density. The experimental accuracy of the two methods was found to be comparable. The advantage of the method is its objectivity. However, its disadvantages are its cost in terms of time and material and it cannot be used to confirm post-vasectomy azoospermia because the method also measures DNA in leucocytes.

DNA↗