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Biomedical subjects

D Potter

Publications and source records attributed to D Potter.

At least 55 records · Page 3Linked to original sources
PubMed1993

A multicenter, randomized, double-blind, placebo-controlled, dose-titration study of oral pilocarpine for treatment of radiation-induced xerostomia in head and neck cancer patients.

PURPOSE: To determine the efficacy and safety of pilocarpine hydrochloride for symptomatic relief of postradiation xerostomia symptoms and for saliva production in patients with head and neck cancer. PATIENTS AND METHODS: One hundred sixty-two head and neck cancer patients who had received at least 40 Gy of radiation (117 patients had received > 60 Gy) with clinically significant xerostomia were enrolled onto a randomized, double-blind, placebo-controlled, multi-center clinical investigation. Patients received 2.5-mg tablets for the first 4 weeks, 5.0-mg tablets for the second 4 weeks, and 10.0-mg tablets for the last 4 weeks of the 12-week study. Patients were allowed to titrate pilocarpine or placebo for improvement in symptoms or to reduce side effects. Patients were evaluated for symptomatic relief by questionnaires and visual analog scales (VAS), and for saliva production by sialometry. RESULTS: Pilocarpine produced a significant improvement (P = .035) in overall global assessments compared with placebo. There was a statistically significant (P = .020) decreased use of oral comfort agents such as artificial saliva, hard candy, and water. Values for symptomatic improvement in dryness approached significance (P = .057). There were statistically significant postdose improvements in whole and parotid salivary flow in pilocarpine treatment groups versus placebo. All pilocarpine dosages tested were judged to be safe. Adverse experiences were primarily sweating, rhinitis, headache, nausea, and urinary frequency, with the most common side effect being mild to moderate sweating. There were no serious drug-related adverse experiences in any of the pilocarpine treatment groups. CONCLUSION: It is concluded that pilocarpine produces clinically significant benefits for the symptomatic treatment of postradiation xerostomia. Best results were obtained with continuous treatment for 8 to 12 weeks with doses greater than 2.5 mg three times per day.

Administration, Oral↗
PubMed1993

Modification of catalytic properties of chicken liver fructose 1,6-bisphosphatase by allicin.

The activity of chicken liver fructose 1,6-bisphosphatase increases dramatically after incubation with allicin, a major biologically active compound produced by garlic. Activation is more pronounced when the enzyme is assayed with Mn2+ than Mg2+. Maximum activation is accompanied by the disappearance of 4 highly reactive sulfhydryl groups per molecule of enzyme. This modification also leads to loss of activation by K+, and reduced sensitivity to inhibition by AMP, fructose 2,6-bisphosphate, and high concentration of fructose 1,6-bisphosphate. All the altered properties induced by allicin can be reversed by dithiothreitol or tris(2-carboxyethyl)phosphine, the latter being much more effective.

Animals↗
PubMed1991

Liver transplantation after paracetamol overdose.

OBJECTIVE: To evaluate the role of liver transplantation after paracetamol overdose. DESIGN: Prospective study of consecutive candidates for transplantation and performance of transplantation over 18 months. SETTING: Liver unit, King's College Hospital, London. MAIN OUTCOME MEASURES: Fulfilment of indicators of poor prognosis, selection for transplantation, transplantation, survival. RESULTS: 30 of 37 patients considered to have a reasonable prognosis with intensive medical care survived. Of 14 of 29 patients considered to have a very poor prognosis and registered for urgent liver transplantation, six received liver transplants, four of whom survived, while seven died and one survived without a transplant. Three of 15 patients with poor prognostic indicators but not selected for transplantation survived. CONCLUSION: Liver transplantation will have a definite but limited role in the management of fulminant hepatic failure induced by paracetamol.

Acetaminophen↗
PubMed1991

Uterine rupture during trial of labor after previous cesarean section.

This study was undertaken to determine the incidence and associations of uterine rupture and dehiscence with an attempted vaginal birth after cesarean section. The charts from 137 patients who had uterine scar separation after a previous cesarean section from 1983 to 1989 were examined. Approximately 9.3% of the 119,395 women who were delivered in that interval had a prior cesarean section. Of those, 68.8% underwent a trial of labor with a 79.2% success rate. The uterine rupture rate in this latter group was 0.8%, while an additional 0.7% had a bloodless dehiscence. Bleeding and pain were unlikely findings with a uterine scar separation (3.4% and 7.6%, respectively). The most common manifestation of a scar separation was a prolonged fetal heart rate deceleration leading to operative intervention (70.3%). We conclude that, although the incidence of uterine rupture was low, the event is most often seen as an acute emergency. Prevention should be directed toward timely diagnosis and prompt management of labor dystocias. Staff and facilities for safe management of a uterine scar separation are a requisite for the conduct of a vaginal birth after previous cesarean section.

Adult↗
PubMed1991

Intracranial and cerebral perfusion pressure changes before, during and immediately after orthotopic liver transplantation for fulminant hepatic failure.

Several centres that perform liver transplantation for fulminant hepatic failure have experience of patients who have not regained consciousness despite adequate graft function. In some of these, decerebration because of elevation in intracranial pressure was thought to have occurred intraoperatively or in the early post-operative period. In the present study six patients with fulminant hepatic failure who were transplanted had extradural monitors inserted before operation. Intracranial pressure had been controlled prior to transplantation and rose during the pre-clamp phase of the operation. Levels fell during the anhepatic phase but rose again during the reperfusion phase (p = 0.033). Overall, from the induction of anaesthesia to the reperfusion phase there was a significant increase in mean intracranial pressure (p less than 0.01). The cerebral perfusion pressure fell after induction of anaesthesia from a median 54 mmHg (range 46-62) to a median 35 mmHg (range 19-49, p less than 0.001) in the pre-clamp phase and remained low throughout the operation. During the first 10 hours after transplantation, three patients had further episodes of intracranial hypertension requiring treatment and it is important that monitoring should be continued through this period.

Adolescent↗
PubMed1990

Rearing in darkness changes visually-guided choice behavior in Drosophila.

To test whether visual experience can affect development of visual behavior in the fruitfly, Drosophila, we measured the visually-guided choice behavior of groups of flies reared in complete darkness, compared with controls reared in a normal light/dark cycle. We used a simple visual preference test, i.e. choice among four different visual targets each consisting of vertical black lines of a particular width on a white background, using a blind testing procedure so that the individual rearing histories were not known by the tester. Both groups of flies were strongly attracted to the vertical lines; however, generally the dark-reared flies were more attracted to the wider stimulus lines than were the control flies. Control experiments in which normally reared adults were kept for several days in darkness showed that the effects of dark-rearing were not simply due to being in darkness, but depended upon the timing of the deprivation. The results indicate that the development of visual behavior can be affected by visual experience in Drosophila and thus open the possibility of using Drosophila for genetic dissection of mechanisms of visual plasticity.

Animals↗
PubMed1990

A randomized trial of open lung biopsy versus empiric antimicrobial therapy in cancer patients with diffuse pulmonary infiltrates.

Twenty-four cancer patients with diffuse interstitial pneumonitis (DIP) were randomized to undergo an open lung biopsy (OLB) within 8 hours of presentation (12 patients) or to receive empiric antimicrobial therapy (ET) with trimethoprim-sulfamethoxazole (TMP-SMX) erythromycin for a minimum of 4 days (12 patients). Patients whose condition deteriorated underwent an OLB on day 4. Eight of 12 patients (67%) having OLB survived versus 10 of 12 (83%) receiving ET (P = .64). Morbidity occurred in nine of 12 (75%) having OLB versus eight of 12 (67%) receiving ET (P = 1.0). Concurrently, there were 14 additional cancer patients with DIP who were not randomized (nine refused, three had a coagulopathy contraindicating surgery, two were excluded by primary care physicians) and who were comparable demographically to the randomized group. Two received OLB and 12 ET. Combining the randomized and nonrandomized groups, eight of 14 (57%) having an initial OLB survived versus 18 of 24 (75%) of ET-treated patients (P2 = .19). Results of the OLB were seven Pneumocystis carinii pneumonia (PCP), five nonspecific pneumonitis (NSP), one cytomegalovirus, and one lymphoma. Results of OLB led to discontinuation of antibiotics in three patients. Of the 24 ET patients, eight failed to improve by day 4 and had an OLB. Results were two NSP, two PCP, two cancer, one blastomycosis, and one Candida pneumonia. Complications were seen in 10 of 14 (72%) initial OLB patients versus 14 of 24 (58%) patients on the ET arm (P = .65). When the complication rate between patients receiving only empiric antibiotics was compared with all patients having an OLB (initially or on day 4), the difference was greater in patients undergoing OLB (37% v 72%, respectively) (P2 = .14). ET with TMP-SMX plus erythromycin and broad spectrum antibiotics in granulocytopenic patients appeared to be as successful and potentially less toxic than an OLB in this study. Although the number of patients in this study was small, these data suggest that a trial of empiric antibiotic management may be reasonable in cancer patients presenting with DIP, especially if they are nonneutropenic.

Adult↗
PubMed1989

Ida Mann--her wartime career, 1939-1949.

Ida Mann's wartime accomplishments were most remarkable. Besides her Harley Street practice and her senior appointment at Moorfields (The Royal London Ophthalmic Hospital), she prevented its closure to ophthalmic patients and chaired the Hospital Management Committee; she investigated the pathology of mustard gas keratitis and formed a Chemical Defence Research Team to study ocular effects of warfare chemicals; she was appointed Margaret Ogilvie Reader in Ophthalmology and senior surgeon to the Oxford Eye Hospital; she established the Nuffield Research Laboratory and was awarded a personal professorship, the first in ophthalmology in Britain, the first professorship given to a woman and the only one in ophthalmology by the University of Oxford. Late in the war she married a cancer research pathologist in whose laboratory she cultured a malignant tumour of the lens. Furthermore, she produced a vast number of outstanding research papers, most notably the authoritative monograph on chemical injury to the anterior segment of the eye.

England↗
PubMed1989

Can UK-14, 304-18 lower IOP in rabbits by a peripheral mechanism?

Unilateral topical administration of alpha 2 adrenoceptor agonists lowers intraocular pressure (IOP) bilaterally in laboratory animals and man. Investigators have suggested that this decrease in IOP is mediated, in part, by alpha 2 adrenoceptors in the central nervous system (CNS). In the present study, the hypotensive activity of the alpha 2 agonist, UK-14,304-18 (UK), was evaluated following topical and intracameral administration. The unilateral administration of a relatively selective alpha 2 adrenoceptor agonist, UK (50 micrograms), lowered IOP bilaterally when applied topically to the eyes of rabbits. Intracamerally administered UK (0.05-50 ug) lowered IOP unilaterally in a dose-related manner with minimal pupillary and cardiovascular changes. The ocular hypotensive action of UK administered intracamerally was absent in rabbits that had been surgically sympathectomized. While these data demonstrate that UK can lower IOP in the rabbit independent of alpha 2 adrenoceptor stimulation in the CNS and other systemic sites, the expression of this response is dependent upon the presence of intact sympathetic innervation.

Administration, Topical↗