Biomedical subjects
Publications and source records attributed to D Allen.
A survey was carried out of 102 members of the general public, asking for their views of the recent changes in the government funding of NHS dentistry. Approximately 80% of those surveyed had heard about the changes. The majority thought that the implications of the change would be a rise in costs to patients and a fall in the number of NHS dentists.
A 2-year-old Arabian filly was referred for evaluation of a serosanguineous vaginal discharge. Palpation per rectum revealed a large, fluid-filled uterus and a uterine mass. The filly developed septic metritis and secondary laminitis as a result of torsion and necrosis of a pedunculated uterine mass. Ovariohysterectomy was performed. The entire cervix was removed with the uterus. Gross examination of the excised uterus revealed 3 intraluminal masses. Histologic evaluation identified the tumors as fibroleiomyoma. The filly recovered completely, and there was no recurrence of the tumor.
The area postrema (AP), a chemoreceptor trigger zone for nausea and vomiting, has been implicated in taste aversion conditioning with LiCl. In addition to taste aversion acquisition, the present studies indicate that a number of other responses to LiCl administration are eliminated by lesions of the AP. These include a behavioral response, 'lying-on-belly' as well as two physiological responses, delayed stomach emptying and hypothermia. These findings suggest that the area postrema is critically involved in the detection of LiCl and in a wide range of responses to this toxin. They also provide strong evidence that the failure to acquire conditioned taste aversions to LiCl-paired flavors after AP lesions can be attributed to the absence of a significant 'illness' response in lesioned animals.
The effects of diazepam (5 mg t.i.d.), suriclone (0.2 and 0.4 mg t.i.d.) and placebo (t.i.d.) were assessed in 12 normal, healthy volunteer subjects after a single dose and after treatment for a period of 8 days. A battery of physiological, psychomotor and subjective tests was administered on days 1 and 8 both before and after drug and after a measured dose of ethanol. The effects of diazepam on the EEG were characteristic of benzodiazepines-a decrease in the slow frequency wave-bands, an increase in fast frequency wave-band and diminished evoked response amplitude. Suriclone had similar effects on fast frequency activity and evoked response amplitude but, in contrast to diazepam, also increased the slow frequency wave-bands after 7 days treatment. Some improvements in performance were seen with suriclone on critical flicker fusion, tapping speed, spiral maze and digit cancellation. In contrast, suriclone impaired performance to a greater extent than diazepam on digit symbol substitution and symbol copying. Body sway was also enhanced by suriclone to a greater extent than diazepam. Subjective ratings for mood and adverse-effects showed few differences between suriclone or diazepam. However, suriclone caused greater gastro-intestinal disturbances than diazepam, especially after ethanol, and subjects rated themselves as more antagonistic and more irritable on suriclone. Ratings for calmness suggested that in contrast to diazepam, suriclone had no anxiolytic effect. Several of the parameters tested showed a build up of effect with diazepam over the treatment period which was not seen with suriclone. It is suggested that this difference may be due to differences in elimination rate.(ABSTRACT TRUNCATED AT 250 WORDS)
We asked the question "is the visual field temporally homogeneous when the well known spatial inhomogeneity is taken into account?" Our results show that the visual field exhibits inhomogeneity for stimuli of low spatial frequency for which the spatial inhomogeneity is minimal. This inhomogeneity takes the form of a reduction in sensitivity for stimuli of low temporal frequency in the periphery and an enhancement of sensitivity for stimuli of high temporal frequency in the periphery. The low temporal frequency loss in the periphery is post-receptoral and must involve a selective loss of sensitivity of the low pass filter. The enhanced high frequency sensitivity may be post-receptoral or purely receptoral. The consequence of such an inhomogeneity for subsequent stages of visual processing is discussed.
Grating acuity was measured in 16-week-old human infants. Three measurement techniques were used: forced-choice preferential-looking (FPL), and two visual-evoked-potential (VEP) techniques. The stimuli were counterphase flickering sinewave gratings with a space-average luminance of -1.0 or 2.0 log cd/m2. Slightly different luminance-dependent changes occur between FPL and VEP acuities, suggesting that some factor influences the two methods differently as stimulus luminance varies. A comparison between FPL acuities and VEP acuities within infants suggests a quantitative relationship between techniques. Infant's acuity for sinewave gratings with a space-average luminance of -2.0, -1.0, 0.0, 1.0 and 2.0 log cd/m2 was also measured using a single VEP paradigm. The results are compared to the same measurements in adults and to infant and adult ideal observers. VEP acuity in this group of infants improves by about 0.5 log units between -2.0 and 0.0 log cd/m2 and remains asymptotic between 0.0 and 2.0 log cd/m2. This result suggests that luminance-dependent changes in infant acuity cannot be fully accounted for by immaturities in the optics and photoreceptor spacing and efficiency.
From 1984-1990, 143 patients with squamous cell or adenocarcinoma of the esophagus were enrolled in a Phase I/II study of neoadjuvant chemotherapy followed by concurrent chemotherapy plus radiotherapy with or without subsequent esophagectomy. Patients received one cycle of Cisplatin or Carboplatin plus Etoposide for squamous cell carcinoma, or Cisplatin or Carboplatin plus 5FU for adenocarcinoma, followed by two cycles of the same chemotherapy given concurrently with 44-46 Gy over 5 weeks. Operable patients then underwent esophagectomy. Inoperable patients and those with positive surgical margins received additional irradiation (16-18 Gy). Twelve percent of the surgical group received preoperative radiotherapy doses > or = 50 Gy. Seventy-two percent (103) had clinical Stage I-III tumors and 28% (40) were clinical Stage IV (1983 American Joint Committee on Cancer criteria). Only clinical Stage I-III patients were analyzed with respect to patterns of failure. Isolated local failure occurred in 19/103 (18%) of clinical Stage I-III patients. Both local and distant relapse occurred in 15/103 (15%), and distant metastases alone occurred in 25/103 (24%). The 3-year actuarial rates of local and distant failures were 45% and 60%, respectively. Among the clinical Stage I-III patients who underwent surgery (n = 58) versus those who did not (n = 45), the 3-year actuarial local and distant failure rates were 30% versus 60% and 45% versus 45%, respectively. Multivariate analysis was performed to identify significant predictors of local control. For all clinical Stage I-III patients, treatment with surgery (p = 0.001) and with three or more cycles of chemotherapy (p = 0.02) were significant predictors of improved local control. Patients who underwent surgery were significantly younger and had a better performance status than those who did not. The improvement in local control with surgery did not translate into better survival, likely on account of a high operative mortality rate in older patients and those receiving > or = 50 Gy preoperatively. We conclude that local control remains poor with concurrent chemotherapy + radiotherapy for esophageal cancer. The addition of surgery improved local control, but distant metastases remain a problem both in this group of patients as well as those treated without esophagectomy. Efforts to improve local control appear warranted, but it remains to be demonstrated that improved local control translates into improved survival in esophageal cancer because of a high rate of distant metastases in patients whose disease is controlled in the esophagus.
A total of 153 breast cancer patients who participated in two trials of adjuvant tamoxifen and who had not recurred were recruited into a study of the long term effects of tamoxifen. There were 60 controls (no tamoxifen), 73 ex-users (mostly for 2 years) and 20 current users (median treatment duration 72 months) and the median follow-up time was 7 years. A wide ranging study of lipids, hormones, bone density and haemostasis was undertaken. When compared with controls, current users had lower cholesterol levels (especially low density cholesterol), and increased triglyceride levels. Thyroid hormones were higher and sex hormone binding globulin was almost doubled. Bone density was non-significantly higher, clotting times were slightly shorter and fibrinogen and antithrombin III levels were reduced. However few of these changes persisted in ex-users, suggesting that most of the biological effects of treatment are reversible on cessation of treatment. This is reassuring for potentially negative side-effects, but also indicates that potentially positive 'side-effects' such as cholesterol lowering only occur while on active treatment.
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In one practice with 14,000 patients an advice line was set aside at designated times to enable patients to speak directly to a doctor on the telephone. The aim of this study was to determine who used the line, why they called, the conditions callers presented with, the action taken by the doctor and whether patients and doctors thought the service was a good idea. A total of 277 calls were made during the five month study period. Responses to a questionnaire were received from doctors for all 277 calls and from 152 patients. It was found that most calls lasted about three minutes. Most of the callers (59%) were known to the doctor taking the call. Users of the advice line were most likely to be women, married people and people with children. Equal numbers of calls were received about new and existing problems. The most frequent reason for calling was to obtain the result of a test (21% of calls). The most frequent diagnosis by the doctors was chronic complaints for which the patient was already receiving treatment (19%). The data from patients and doctors were similar. In 30% of cases callers were advised to take medicine, mostly a prescription to be collected (16%), while a few callers received a home visit (7%). Doctors thought they provided reassurance in 26% of cases while callers thought they had received reassurance in 43% of cases. If the advice line had not been available three quarters of the respondents would have made an appointment and 13% would have asked the doctor to make a home visit.(ABSTRACT TRUNCATED AT 250 WORDS)
Tuberculosis is a common cause of cavitating pneumonia in Singapore. In patients with the human immunodeficiency virus (HIV), cavitary pneumonias mimicking tuberculosis can mislead the clinician, delaying diagnosis, resulting in increased morbidity. We describe a HIV seropositive patient with cavitating pneumonia in whom the diagnosis of Pneumocystis carinii pneumonia (PCP) was ultimately established only on bronchoscopy.
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Response to endocrine therapy and its relationship to the clinical features of the disease were studied in 84 Egyptian patients with inoperable, locally advanced or metastatic breast cancer. Twenty-four premenopausal patients were treated by oophorectomy with or without concurrent prednisolone. Only one of 20 evaluable patients achieved an objective response. Median time to progression for premenopausal patients was 3 months. Sixty postmenopausal patients received tamoxifen 10 mg twice daily either alone or with prednisolone. Fourteen of 57 (25%) evaluable patients achieved an objective response (four complete remission, 10 partial remission). Median duration of response was 13 months and median time to progression for all postmenopausal patients was 5 months (range 1-30 months). The outcome for postmenopausal patients was similar to that found in a parallel study at Guy's Hospital, London. The response rate for premenopausal Egyptian patients was, however, disappointing and lends support to the claim that breast cancer in Egyptian women is particularly aggressive.
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Traumatic rupture of the calcaneal tendon was diagnosed in a 3-year-old female goat. Clinical features included tarsal hyperflexion and diffuse swelling in the area of the calcaneal tendon. Surgical repair consisted of debridement of devitalized tissue and transposition of the tendon of the peroneus longus muscle to bridge the calcaneal tendon defect. Adequate postoperative immobilization followed by gradual introduction of tendon loading allowed a favorable outcome.
An 8-year-old Arabian stallion had signs of severe tailhead pruritus and slowly progressive loss of tail tone for 3 months. Palpation per rectum and radiography of the sacrocaudal region revealed a transverse, ventrally displaced fracture of the caudal portion of the sacrum. Surgical decompression and tail amputation resulted in complete recovery of athletic and reproductive function. Evidence of cauda equina neuritis was not seen on histologic examination of nerve roots obtained at surgery.
The effects of a 10 day administration of clomipramine (25-50 mg t.i.d.), alprazolam (0.25-0.75 mg t.i.d.) and placebo were assessed in normal volunteers in a double-blind cross-over study. A battery of physiological, psychomotor and cognitive tests was administered both before and 3 h after drug on days 1, 5 and 10. The effects of alprazolam on EEG and evoked potentials were characteristic of benzodiazepines; clomipramine had little effect. In contrast, reaction speed was markedly slowed by clomipramine but little affected by alprazolam. Neither drug produced any accumulation of effect on a verbal recall task but neither did tolerance develop to the acute impairments produced by active treatments. Alprazolam produced an increase in levels of forgetting, especially on day 5. Subjective ratings for mood and bodily symptoms were adversely affected by clomipramine but little altered by alprazolam. It is suggested that some of the differences between drug treatments may be due to differences in the speed of onset of tolerance.