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Biomedical subjects

D Williams

Publications and source records attributed to D Williams.

At least 145 records · Page 8Linked to original sources
PubMed1999

Comparison of the angiojet rheolytic catheter to surgical thrombectomy for the treatment of thrombosed hemodialysis grafts. Peripheral AngioJet Clinical Trial.

PURPOSE: To compare the clinical effectiveness of the AngioJet F105 rheolytic catheter to that of surgical thrombectomy for the treatment of thrombosed hemodialysis grafts. MATERIALS AND METHODS: This was a multicenter, prospective, randomized trial comparing technical success, primary patency, and complication rates. A total of 153 patients were enrolled: 82 patients in the AngioJet group and 71 patients in the surgical thrombectomy group. Patient follow-up was performed 24-48 hours, 1 month, and 6 months after the procedures. RESULTS: Technical success, as defined by the patient's ability to undergo hemodialysis treatment, was 73.2% for the AngioJet group and 78.8% for the surgical thrombectomy group (P = .41). The primary patency rates of the AngioJet group were 32%, 21%, and 15% at 1, 2, and 3 months, respectively. The primary patency rates for the surgical group were 41%, 32%, and 26% at 1, 2, and 3 months, respectively. This difference approached statistical significance (P = .053). The groups had similar complication rates-14.6% in the AngioJet group and 14.1% in the surgery group-although the surgery group had more major complications (11.3%). In the AngioJet group, there was a transient increase in plasma-free hemoglobin, which normalized within 24-48 hours. CONCLUSIONS: The AngioJet F105 catheter provides similar clinical results when compared to surgical thrombectomy for the treatment of thrombosed hemodialysis grafts. The difference in patency rates between these two techniques approached statistical significance. In addition, results of both thrombectomy methods were inferior to those suggested by the Dialysis Outcomes Quality Initiative guidelines.

Adult↗
PubMed1999

Accessing data from external centralized sources to enhance analysis of a completed clinical trial.

After the data collection phase of a clinical trial has been completed, new hypotheses may surface which require additional data before they can be tested. In the Veterans Affairs Cooperative Study on Single Drug Therapy of Hypertension, we investigated the relationship between location of the participating center, race and ability to control blood pressure. The analysis indicated poorer blood pressure control among sites located in the "stroke belt" (southeastern United States), especially among African-Americans. We sought to determine whether the effect was attributable to socioeconomic patterns; however, income data were not collected as part of the original study. Therefore, we accessed centralized data bases to obtain zipcode-level income information for the randomized study patients. This approach yielded estimates of income data for 94.3% of the patients and compared favorably to data acquisition rates for variables which were collected prospectively in the study.

Antihypertensive Agents↗
PubMed1999

Immunosuppressive therapy for ulcerative colitis: results of a nation-wide survey among consultant physician members of the British Society of Gastroenterology.

BACKGROUND: The role of immunosuppressive therapy in ulcerative colitis remains controversial. There is little information available on how frequently immunosuppressives are used, the circumstances, dose and duration of use and perceived benefit. METHODS: A postal survey was sent to consultant gastroenterologist members of the British Society of Gastroenterology. RESULTS: Questionnaires were returned by 81% of the 496 UK consultants approached. Azathioprine use was frequent, with 93% reporting previous use and 86% use within the past year. Although 95% usually prescribed a < or =2 mg/kg dose, only 39% were prepared to prescribe higher doses. There was marked variation in duration of use, with 46% using azathioprine for <2 years and 17% continuing it for 4 years or longer. Consultants with more experience of azathioprine in ulcerative colitis used it at higher maintenance doses for longer periods, and in patients with less extensive disease. Cyclosporin use was reported by 47% of those caring for ulcerative colitis patients, with 36% having used it at least once in the past year. However, 65% of users estimated that fewer than 50% of patients subsequently avoided colectomy. On stopping cyclosporin only 21% always introduced an alternative immunosuppressive, while 23% never did so. Potentially serious side-effects attributable to azathioprine and cyclosporin were reported by 36% and 45% of users of each drug, respectively. CONCLUSIONS: This survey reveals considerable variation in the amount and pattern of immunosuppressive use in ulcerative colitis, with serious side-effects commonly seen. There is a pressing need for further randomized controlled trials to provide reliable evidence as to how immunosuppressive therapy should be used in ulcerative colitis.

Azathioprine↗
PubMed1999

Fluorescein kinetics in interstitial fluid harvested from diabetic skin during fluorescein angiography: implications for glucose monitoring.

BACKGROUND: Glucose monitoring based on sampling skin interstitial fluid (ISF) is being developed as an alternative to fingerstick blood glucose monitoring. Time delays between rapidly changing levels of glucose in blood and interstitial fluid have been reported in the literature to be between 5 and 20 minutes. This study investigated the time delay between the injection of a small molecular weight fluorescent tracer into the circulation and interstitial fluid. METHODS: Diabetic subjects undergoing fluorescein angiography were studied. Skin ISF was sampled using a proprietary microporation and harvesting process. ISF was drawn through micropores created in the stratum corneum. After intravenous injection of sodium fluorescein, samples of ISF were drawn from 2 sites for 30 seconds over a period of 20 minutes. Fluorescence levels in ISF were measured with a fluorometer and used to create ISF fluorescein concentration versus time profiles. RESULTS: The ISF fluorescein versus time profiles were characterized by a rapid rise followed by a slow decay. The time to peak of the ISF fluorescein concentration ranged from 2-4 minutes for the patients studied. CONCLUSIONS: Intravenous injection of a bolus of low molecular weight fluorescent tracer was used to estimate the time delay between changing glucose levels in blood and ISF. The results indicate that the ISF sampling technology utilized here is capable of tracking rapidly rising levels of blood glucose.

Adult↗
PubMed1999

Functional outcome of plate fusions for disorders of the occipitocervical junction.

Twenty-eight patients with average followup of 27 months (range, 12-51 months) required occipitocervical fusion with plates. A 1992 to 1996 consecutive case series enrolled patients prospectively from two institutions. Five surgeons participated. Sixteen patients had inflammatory arthritis; four, osteogenesis imperfecta; three, tumors; three, congenital anomalies; one, pseudarthrosis after odontoid fracture; and one, osteoarthritis. Twenty-two of 28 (78.6%) patients had serious comorbid medical conditions. Additional halo immobilization of 6 weeks was used in 16 of 27 patients. Four patients required revision surgery. No patients showed a decline in neurologic status and average neurologic improvement was one Nurick grade. Two-year followup showed 13 (50%) excellent, nine (34.6%) good, two (7.7%) fair, and two (7.7%) poor outcomes based on a functional outcome scale. There were three deaths during the followup period (overall mortality rate of 10.7%). One death was attributable to airway obstruction, one death 14 months postoperatively was attributable to late Methicillin resistant Staphylococcus aureus sepsis at the bone graft donor site, and one death 41 months postoperatively was attributable to a stroke. The overall fusion rate was 85.2% (23 of 27 patients), with a 96.3% (26 of 27 patients) occipitocervical fusion rate. Three patients had a possible asymptomatic end segment pseudarthrosis with screw loosening. Twenty-two of 26 (84.6%) interviewed patients would choose the surgery again if given the choice.

Adolescent↗
PubMed1999

Intraoperative acetazolamide in the prevention of intraocular pressure rise after pars plana vitrectomy with fluid-gas exchange.

PURPOSE: To assess the effect of intraoperative acetazolamide (Diamox) on postoperative intraocular pressure (IOP) in gas-filled, vitrectomized eyes. METHODS: We conducted a prospective randomized clinical trial of 63 consecutive patients undergoing pars plana vitrectomy with total fluid-gas exchange and long-acting intraocular gas tamponade. Patients were randomized by a blind draw to receive either intravenous 500 mg acetazolamide (Diamox) (Group 1) or no treatment (Group 2) at the conclusion of the operative procedure. Intraocular pressures at the conclusion of surgery (IOP-1), 4-8 hours following surgery (IOP-2), and on the first postoperative day (IOP-3) were measured using an Oculab Tono-Pen. RESULTS: Patients in Groups 1 and 2 showed similar mean IOP on postoperative day 1 (20.48+/-7.84 mmHg versus 19.89+/-7.89 mmHg). A similar incidence of IOP-2 greater than 30 mmHg (1 versus 3 patients with high IOP) and IOP-3 greater than 30 mmHg (4 versus 3 patients with high IOP) was seen. Patients in Group 1 had a lower mean IOP at 4-8 hours postoperatively (16.25+/-6.47 mmHg) than those in Group 2 (20.13+/-6.33 mmHg). No correlation could be demonstrated between IOP-1 and subsequent IOP. However, IOP on the first postoperative day (IOP-3) was strongly correlated with IOP 4-8 hours after surgery (IOP-2) (P = 0.0001). No protective effect of Diamox could be demonstrated on either IOP-2 or IOP-3. CONCLUSIONS: No protective effect against pressure rise could be demonstrated for intraoperative acetazolamide (Diamox) in the prophylaxis of IOP rise following pars plana vitrectomy and total fluid-gas exchange with long-acting intraocular gas.

Acetazolamide↗
PubMed1999

Facial burns in children: a series analysis with implications for resuscitation and forensic odontology.

This study comprises a continuous (1981-1995) unselected series of all children who died from thermal injuries in the State of Queensland, Australia. One hundred and six children, so identified, died from incineration (35 per cent), respiratory burns with smoke or carbon monoxide inhalation (33 per cent), body surface area burns comprising greater than 60 per cent (9 per cent) and electrocution (20 per cent). The burn fatality rate was 0.98 per hundred thousand children (0-14 years) per year, with no secular trend and, specifically, no reduction in the annual rate of such fatalities. Eighty-two children (49 males) had concomitant facial injuries, both thermal and nonthermal; of whom 55 per cent were under the age of five years. Sixty (73 per cent) child burn victims died in house fires. Forensic odontology is important in confirming the age of such victims in single incinerations but is of limited value when larger numbers of children are incinerated, because of the relative lack of dental restorations in the infant and pre-school age group. Of the 82 children with facial and airway injuries, 12 per cent had only mild or superficial facial damage and only seven (8 per cent) were alive or resuscitable at the time of rescue from the conflagration or burning injury. child deaths from burns contributed an annual loss rate of 506 years of potential life lost (YPLL) in a population of 3 million of whom 21.5 per cent were children under the age of 15 years. Airway management and resuscitation, in the context of managing surviving burn victims of any age with facial injuries, pose special difficulties. Inhalational burns (smoke and the gases of conflagration) result in a mortality greater than 60 per cent. Although 81 per cent of children showed evidence of airway obstruction, analysis of current data indicates that a maximum of 8 per cent could have survived with airway maintenance and protection. Inhalational burns (to both upper and lower airways) grossly reduce survivability. Primary prevention would seem vital and thus remains a major challenge to reduce the incidence of such deaths. Some strategies include advocacy to promote the compulsory installation of smoke alarms, family drills to practise escape and the teaching of 'first aid for all'

Adolescent↗
PubMed1999

The prevalence of dental erosion in the maxillary incisors of 14-year-old schoolchildren living in Tower Hamlets and Hackney, London, UK.

The purpose of this study was to assess the prevalence of dental erosion in the maxillary incisors of a sample of 14-year-old schoolchildren and to explore the aetiological factors responsible for that erosion. The cross-sectionally design study took place in secondary schools in inner-city London, UK and involved 525, 14-year-old schoolchildren selected at random in a clinical examination and a self-completed questionnaire. The outcomes measures for dental erosion were; the prevalence, the area and depth of lesions and the risk factors. The prevalence of labial and palatal erosion was 16.9 per cent and 12 per cent respectively. Risk factors and behaviours including daily frequency of ingestion of acidic fruits and drinks, food vomiting, toothbrushing frequency, and swimming habits were not shown to have any relationship with the presence of erosion. It was concluded that the prevalence of erosion in the maxillary incisors of this sample was higher labially and lower palatally than in previously reported national figures. The risk factors which were investigated were not shown to have any relationship with the presence of erosion. Further investigations of these issues are necessary to establish whether or not dental erosion is a public health problem in the UK.

Acids↗
PubMed1999

Inducible nitric oxide synthase is an endogenous neuroprotectant after traumatic brain injury in rats and mice.

Nitric oxide (NO) derived from the inducible isoform of NO synthase (iNOS) is an inflammatory product implicated both in secondary damage and in recovery from brain injury. To address the role of iNOS in experimental traumatic brain injury (TBI), we used 2 paradigms in 2 species. In a model of controlled cortical impact (CCI) with secondary hypoxemia, rats were treated with vehicle or with 1 of 2 iNOS inhibitors (aminoguanidine and L-N-iminoethyl-lysine), administered by Alzet pump for 5 days and 1. 5 days after injury, respectively. In a model of CCI, knockout mice lacking the iNOS gene (iNOS(-/-)) were compared with wild-type (iNOS(+/+)) mice. Functional outcome (motor and cognitive) during the first 20 days after injury, and histopathology at 21 days, were assessed in both studies. Treatment of rats with either of the iNOS inhibitors after TBI significantly exacerbated deficits in cognitive performance, as assessed by Morris water maze (MWM) and increased neuron loss in vulnerable regions (CA3 and CA1) of hippocampus. Uninjured iNOS(+/+) and iNOS(-/-) mice performed equally well in both motor and cognitive tasks. However, after TBI, iNOS(-/-) mice showed markedly worse performance in the MWM task than iNOS(+/+) mice. A beneficial role for iNOS in TBI is supported.

Animals↗
PubMed1999

Levels of high energy phosphate in the dorsal skin of the foot in normal and diabetic adults: the role of 31P magnetic resonance spectroscopy and direct quantification with high pressure liquid chromatography.

Determining viability of tissues and wound-healing potential in diabetic patients remains a significant challenge. Current methods for preoperative assessment of wound-healing potential (pressures in the ankle, temperature of tissues, transcutaneous measurements of oxygen, and systemic nutritional status) are indirect, in that they characterize the delivery of oxygen or other nutrients to the cells. A noninvasive means to measure adenosine triphosphate (ATP) and phosphocreatine (PCr), the fundamental high energy phosphate substrates of oxidative energy-metabolism in the skin, has been devised by using magnetic resonance spectroscopy (MRS). The signal-to-noise ratio of bioenergetic metabolites in the skin was 86% lower in five patients with diabetes who had ischemia of the lower extremity compared with five control subjects (P < 0.0001), suggesting that the concentration of high energy metabolites in diabetic patients was reduced. The ratio of ATP/phosphocreatine (PCr) in patients with diabetes was also significantly lower than in controls (P < 0.01). Chewing a single piece of nicotine gum reduced the measured concentrations of ATP and PCr in control subjects by an average of 18% and by an average of 75% in subjects with diabetes. To verify these results in a second experiment, skin was harvested from the surgical wound sites in eight patients with diabetes undergoing elective amputation, eight patients with diabetes undergoing elective foot surgery, and ten age-matched control (nondiabetic) patients undergoing elective foot surgery. Analysis of ATP and PCr using high pressure liquid chromatography corroborated MRS findings, showing a significant reduction in ATP and PCr in diabetic skin. Depression of metabolites was more severe in the patients with diabetes undergoing amputation than in the ones undergoing elective surgery. Results demonstrate depression of metabolites in the skin of patients with diabetes and suggest that MRS with 31p may be useful in characterizing metabolites in the skin.

Adenosine Triphosphate↗
PubMed1999

The collaboration process in HIV prevention and evaluation in an urban American Indian clinic for women.

Collaboration between providers and researchers can be key to doing women's HIV prevention that is holistic, gender sensitive, and responsive to communities. This report centers on providers' and evaluators' experiences in developing and implementing a project promoting "healthy relationships" with low-income women from different ethnicities at an urban American Indian clinic. During planning, decisions on the health problems to be targeted, division of labor, program goals, resource allocation, evaluation design, and outcome measures were jointly made. Other factors were the input of participants and the influence of American Indian values at the clinic. The implementation process was fully collaborative. There are implications for creating conditions for successful collaborations in health education.

Community Networks↗
PubMed1999

Pregnancy and the heart.

Pregnancy places a huge demand on the heart. Such a burden cannot always be met by women with pre-existing heart disease. This article covers the important physiological changes of healthy pregnancy, and discusses how to assess and manage heart disease during pregnancy.

Anti-Arrhythmia Agents↗
PubMed1999

Medical missions.

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Delivery of Health Care↗