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Biomedical subjects

D Williams

Publications and source records attributed to D Williams.

At least 181 records · Page 10Linked to original sources
PubMed1998

PET scanning in head and neck oncology: a review.

BACKGROUND: The objective of this study was to review and describe the usage of fluorine-labeled deoxyglucose (FDG) and positron emission tomography (PET) in the diagnosis and management of head and neck cancer. METHODS: Several prospective series,-including 159 newly diagnosed and previously untreated and 23 previously irradiated head and neck squamous cell carcinoma patients initially seen at the Wake Forest University Medical Center and evaluated by clinical examination, conventional computed tomography/ magnetic resonance imaging (CT/MRI) scans, PET scans, and histopathologic studies,-were reviewed and the findings summarized for comparison of the correct differentiation of primary and metastatic cancers and for postirradiation tumor clearance in a subsegment of those cases. RESULTS: Positron emission tomography scanning using a fluorine-labeled deoxyglucose (FDG) radiotracer proved as reliable as conventional scanning for primary and metastatic tumor identification. Compared with clinical examination, PET was better for identification of nodal metastatic tumors but poorer for small primary tumors. For previously irradiated patients treated at least 4 months before the test, PET scanning was clearly superior to clinical examination and conventional imaging in differentiating tumor recurrence from soft-tissue irradiation effects. CONCLUSIONS: Fluorine-labeled deoxyglucose-PET scanning is comparable to conventional imaging of head and neck cancers in detecting primary and metastatic carcinoma. Lack of anatomic detail remains its major drawback. Currently, its greatest role is in the evaluation of the postradiotherapy patient.

Fluorodeoxyglucose F18↗
PubMed1998

Safety of trovafloxacin in treatment of lower respiratory tract infections.

Safety and toleration of oral trovafloxacin has been assessed in Phase III trials in patients with acute lower respiratory tract infections. Patients were treated orally with either trovafloxacin 100 or 200 mg (n=881) or a comparator (500 or 1000 mg amoxicillin, or 625 mg amoxicillin/clavulanic acid; n = 593). Adverse events were recorded in 112 (12.7%) trovafloxacin- and 74 (12.5%) comparator-treated patients. Frequency of effects on the autonomic nervous, musculoskeletal, respiratory, special senses, urinary and reproductive systems was <1%. Photosensitivity reactions were not reported in trovafloxacin-treated patients. Central or peripheral nervous system adverse effects (headache and dizziness) were slightly more common in trovafloxacin-treated patients (4.4% vs 1.9%). Patients treated with comparators experienced gastrointestinal events more frequently (6.1% vs 8.3%). Comparable incidences of adverse events were reported in patients > or = 65-years-old. Most events were mild to moderate in severity. Treatment was discontinued because of an adverse event in 18 (2%) trovafloxacin- and four (0.7%) comparator-treated patients. Despite the high prevalence of risk factors, serious adverse events were rare and the mortality rate over the 35-day study period was low: trovafloxacin 0.8%, comparator agents 1.5%. Laboratory test abnormalities were recorded in less than 1% of patients in either treatment group.

Acute Disease↗
PubMed1998

Visual field defect after pars plana vitrectomy.

OBJECTIVE: This study aimed to report the occurrence of visual field defects after pars plana vitrectomy (PPV) for the treatment of each of the following conditions: macular hole (MH), subretinal neovascular membrane (SRNVM), and epiretinal membrane proliferation (EMP). This study also aimed to speculate on the pathogenic mechanisms for the observed field defects. DESIGN: Noncomparative case series. PARTICIPANTS: The study included 48 subjects (50 eyes). Twenty-one of the 50 eyes had stage III MH, 13 eyes had SRNVM, and 16 eyes had EMP. TESTING: Goldmann kinetic perimetry was performed postoperatively. MAIN OUTCOME MEASURE: Visual field defects. RESULTS: Nine (18%) of the 50 eyes had visual field defects. Four (19%) of the 21 eyes with MH and 5 (38%) of the 13 eyes with SRNVM had visual field defects. Of the 16 patients who had epiretinal membrane peeling, none had a visual field defect. An air-fluid exchange had been performed in all patients found to have a postvitrectomy field defect. The difference in rate of visual field defects in eyes that had air-fluid exchange (EMP group) was statistically significant (P < 0.05, chi-square). No significant correlation was found between visual field defect and preoperative intraocular pressure, postoperative intraocular pressure, patient's age, and iatrogenic detachment of the vitreous cortex. The field defects identified were altitudinal (2 eyes), baring of the blind spot (1 eye), inferotemporal (3 eyes), inferonasal (2 eyes), and superonasal (1 eye). CONCLUSIONS: Central and peripheral visual field defects may occur after PPV for the treatment of MHs or SRNVMs. Air-fluid exchange procedure was the common denominator in all of the patients found to have visual field deficit. The etiology is likely to be trauma to the optic nerve region during the air-fluid exchange procedure.

Adult↗
PubMed1998

A case controlled comparison of open and laparoscopic splenectomy in children.

BACKGROUND: This case controlled study compares the efficacy, safety, and cost of laparoscopic splenectomy (LS) and open splenectomy (OS) for hematologic disorders in children. METHODS: The records of 82 consecutive children and adolescents undergoing splenectomy for hematologic disorders between August 1994 and September 1997 were reviewed retrospectively. RESULTS: Fifty patients underwent LS by a lateral approach and 32 underwent OS through a left subcostal incision. Mean age was 7.76 years for LS and 6.9 years for OS. Patient weights were similar: (LS, mean 30.5 kg; OS, mean 27.6 kg). Hematologic indications included hereditary spherocytosis in 43 children (LS 26, OS 17), sickle cell anemia with sequestration in 13 (LS 7, OS 6), immune thrombocytopenic purpura in 14 (LS 8, OS 6), and 12 with other disorders (LS 9, OS 3). Concomitant cholecystectomy was performed in 10 of 50 LS and 6 of 32 OS cases. Accessory spleens were identified in 8 of 32 (25%) OS and 9 of 50 (18%) LS cases (P = .578). No LS procedures required conversion to OS. The mean estimated blood loss was 54.4 mL for LS and 49.0 mL for OS (P = .233). LS required a longer operative time (115 vs 83 minutes, P = .002), less need for postoperative intravenous narcotic (51% vs 100%, P < .0001), lower total narcotic doses (0.239 vs 0.480 mg/kg morphine, P = .006), shorter length of hospital stay (1.4 +/- 0.97 vs 2.5 +/- 1.43 days, P = .0001), and lower average total hospital charges ($5713 vs $6564) than OS. There were no deaths or major complications in either group. CONCLUSIONS: Laparoscopic splenectomy is a safe and effective procedure in children with hematologic disorders resulting in longer operative times, less narcotic administration, shorter length of stay, and lower total hospital charge.

Adolescent↗
PubMed1998

Immunogenicity of two efficacious outer membrane protein-based serogroup B meningococcal vaccines among young adults in Iceland.

Serum bactericidal activity (SBA) and ELISA antibody levels elicited by two efficacious serogroup B meningococcal vaccines were measured in a controlled trial involving 408 15- to 20-year-olds. Subjects were given two doses at a 6-week interval of a serogroup B or control vaccine. Response was defined as > or = 4-fold rise in antibody level. After two doses of the Finlay Institute (Havana) vaccine at 12 months, the proportions of SBA and ELISA responders were not different from those of the control group (15% and 17% [vaccine] vs. 13% and 9% [control], P > .05). After two doses of the National Institute of Public Health (Oslo) vaccine, there were more SBA and ELISA responders than in the control group (47% and 34% [vaccine] vs. 10% and 1% [control]) or the Finlay Institute vaccine group (P < .05 for both). SBA and ELISA may be insensitive correlates for protective efficacy for some outer membrane protein-based serogroup B meningococcal vaccines.

Adolescent↗
PubMed1998

Induction of the antigen 85 complex of Mycobacterium tuberculosis in sputum: a determinant of outcome in pulmonary tuberculosis treatment.

Sputum quantitative culture, acid-fast smear, days-to-positive by BACTEC, and Mycobacterium tuberculosis antigen 85 complex were monitored during therapy in 42 patients with pulmonary tuberculosis (TB). By BACTEC, 4 patients were persistently positive on days 90-180, and treatment ultimately failed in 2 of these. Antigen 85 expression increased in subjects in whom disease persisted (persisters) from days 0 to 14 when the difference between persisters and nonpersisters was statistically significant (P = .002). Only antigen 85 complex values at day 14 suggested TB persistence at or after day 90. All subjects with day 14 antigen 85 complex values < 60 pg/mL responded rapidly to treatment and were cured. Of those with values > 60 pg/mL, in 33% TB persisted at or after day 90 and treatment failed in 17%. Biologic factors expressed early in therapy, not related to compliance or resistance, may exert a substantial influence on outcome. The antigen 85 complex is critical in cell wall biosynthesis and is induced by isoniazid in vitro. Its induction may represent an adaptive transition to a persistent state during therapy.

Adult↗
PubMed1998

The special prenatal clinic: one approach to women and substance abuse.

We aimed to determine if the trend in substance use in this central core of a large inner-city area confirmed an increase in marijuana use among young women < 22 years of age as childbearing years were beginning or if marijuana use and harder drug use were greatest among women beyond the teens and the early second decade of life and to describe one prenatal care intervention. Statistical reports for the Special Prenatal Clinic, a Harlem clinic for women with a current or past history of substance use, were reviewed from 1985 (the clinic's inception) through March 1996 to determine the trends, patterns, and types of drug use. Findings chronicled the beginning and rise in crack cocaine use, especially after 1986, confirmed an increase in marijuana use by adolescents since 1992, and suggest that the risk for use of hard drugs increases with age, predominantly in the childbearing years. Intervention by the Special Prenatal Clinic aided case-finding, allowed for comprehensive care, offered women opportunities for behavior change, and increased their chances of keeping their babies after delivery.

Adolescent↗
PubMed1998

Mortality and rebleeding following Transjugular Intrahepatic Portosystemic Stent Shunt for variceal haemorrhage.

The present study investigates clinical factors associated with decreased survival following Transjugular Intrahepatic Portosystemic Stent Shunt (TIPSS). Sixty-seven patients underwent TIPSS for bleeding related to portal hypertension, 42 (63%) on an urgent basis. TIPSS was successfully placed in 65 (97%) patients with no fatal procedural complications. Thirty day mortality was 21%, there being several predictive factors: transfer from another institution, urgency of procedure, sepsis, encephalopathy, higher mean serum bilirubin and low serum albumin. However, using regression analysis, 30 day mortality was predicted independently only by severe liver disease (Child-Pugh C, P= 0.003) and older age (P= 0.003). When stratified by Child-Pugh class, cumulative survival rates at 1 year for class A, B and C were 100, 90 and 34%, respectively. Only three of 25 patient deaths were due to variceal rebleeding. Thirty (46%) patients had a total of 41 rebleeding episodes, with mean time to first rebleed of 4.8 months (range, 3 days-38 months). Cumulative rebleeding rate at 1 year was 25%. Log-rank analysis did not reveal a significant difference in overall survival between rebleeders and non-rebleeders (P= 0.125). When investigated, shunt abnormalities (stenosis, occlusion) were identified in all cases of rebleeding. Our findings confirm TIPSS can be safe and effective in the control of refractory variceal haemorrhage. However, prognosis remains poor for patients with advanced liver disease, particularly if older and in the emergency setting. Vigilant surveillance and high rate of intervention is necessary to maintain shunt patency. Consideration could be given to elective shunt surgery instead of TIPSS for patients with recurrent bleeding and good prognosis liver disease.

Esophageal and Gastric Varices↗
PubMed1998

Comparison of the efficacy of free and non-ionic-surfactant vesicular formulations of paromomycin in a murine model of visceral leishmaniasis.

Non-ionic-surfactant vesicular (NIV) formulations of paromomycin have been tested in-vitro and in-vivo for their activity against Leishmania donovani. Production of NIV was dependent both on the surfactant used and on the concentration of paromomycin; only two of the surfactants studied formed vesicles at the highest paromomycin concentration (9 mg mL(-1)). At surfactant-lipid concentrations > or = 1.5 mM, suspensions of NIV (drug- or glucose-loaded) were cytotoxic to macrophages infected with L. donovani; high levels of nitrite were produced in cell supernatants. At surfactant-lipid concentrations < 1.5 mM, drug-loaded NIV were more effective than the same dose of free drug, in terms of the percentage of cells infected and the number of parasites/cell. At surfactant-lipid concentrations < or = 0.15 mM, drug-loaded NIV were ineffective in-vitro. In-vivo, treatment with decaethylene glycol mono n-hexadecyl ether paromomycin NIV was more effective than hexaethylene glycol mono n-hexadecyl ether paromomycin NIV, in terms of suppression of liver and spleen parasite burdens. Against liver parasites, both types of paromomycin-loaded NIV were more effective than free drug. Neither the NIV nor free forms of paromomycin caused significant suppression of bone-marrow parasites. The study shows that entrapment of paromomycin in NIV can be used to increase its antileishmanial activity in-vitro and in-vivo.

Animals↗
PubMed1998

Differential regulation of the interleukin-12 receptor during the innate immune response to Leishmania major.

Previous studies have shown the central role of interleukin 12 (IL-12) in the development of resistance to Leishmania major infection in C3H mice. We now show that during the innate immune response the lymph node cells of L. major-infected C3H mice upregulate the IL-12 receptor on CD4(+), CD8(+), and B220(+) cells. An increase in the ability of the lymph node cells to bind IL-12 correlates with 9.3- and 4.6-fold increases in the mRNA expression levels of the IL-12Rbeta1 and -beta2 subunits, respectively. In contrast, BALB/c mice, which are susceptible to L. major infection, have no increase in the ability of the lymph node cells to bind IL-12 and correspondingly smaller increases in the mRNA expression levels of the IL-12Rbeta1 and -beta2 subunits of 2- and 1.5-fold, respectively. Neutralizing IL-4 and the administration of exogenous IL-12 upregulate IL-12R expression in BALB/c mice, while the neutralization of IL-12 in C3H mice blocks increased IL-12 receptor expression. These experiments reveal an important role for the regulation of the IL-12 receptor during the innate immune response after infection of mice with a pathogen.

Animals↗
PubMed1998

Mitochondrial redox state as a potential detector of liver dysoxia in vivo.

Dysoxia can be defined as ATP flux decreasing in proportion to O2 availability with preserved ATP demand. Hepatic venous beta-hydroxybutyrate-to-acetoacetate ratio (beta-OHB/AcAc) estimates liver mitochondrial NADH/NAD and may detect the onset of dysoxia. During partial dysoxia (as opposed to anoxia), however, flow may be adequate in some liver regions, diluting effluent from dysoxic regions, thereby rendering venous beta-OHB/AcAc unreliable. To address this concern, we estimated tissue ATP while gradually reducing liver blood flow of swine to zero in a nuclear magnetic resonance spectrometer. ATP flux decreasing with O2 availability was taken as O2 uptake (VO2) decreasing in proportion to O2 delivery (QO2); and preserved ATP demand was taken as increasing Pi/ATP. VO2, tissue Pi/ATP, and venous beta-OHB/AcAc were plotted against QO2 to identify critical inflection points. Tissue dysoxia required mean QO2 for the group to be critical for both VO2 and for Pi/ATP. Critical QO2 values for VO2 and Pi/ATP of 4.07 +/- 1.07 and 2.39 +/- 1.18 (SE) ml . 100 g-1 . min-1, respectively, were not statistically significantly different but not clearly the same, suggesting the possibility that dysoxia might have commenced after VO2 began decreasing, i.e., that there could have been "O2 conformity." Critical QO2 for venous beta-OHB/AcAc was 2.44 +/- 0.46 ml . 100 g-1 . min-1 (P = NS), nearly the same as that for Pi/ATP, supporting venous beta-OHB/AcAc as a detector of dysoxia. All issues considered, tissue mitochondrial redox state seems to be an appropriate detector of dysoxia in liver.

Acetoacetates↗
PubMed1998

The effects of antivenom and verapamil on the haemodynamic actions of Chironex fleckeri (box jellyfish) venom.

The efficacy of antivenom and verapamil against Chironex fleckeri (box jellyfish) venom was investigated in monitored mechanically ventilated piglets. Chironex fleckeri tentacle extract alone, a mixture of tentacle extract with antivenom, and verapamil before tentacle extract were administered intravenously to groups of animals. Tentacle extract caused severe systemic hypotension, cardiac dysrrhythmias, pulmonary hypertension, haemolysis and hyperkalaemia. These effects were prevented by pre-incubation of tentacle extract with antivenom. Verapamil did not prevent any effect of venom, exacerbated cardiovascular collapse and increased mortality. We conclude that antivenom neutralizes the cardiovascular, haemolytic and hyperkalaemic effects of box jellyfish venom. Verapamil does not prevent any of these effects and is contra-indicated for treatment of envenomation.

Animals↗
PubMed1998

Mental disorder and violence. A special (high security) hospital study.

BACKGROUND: From a first clinical description of a complete resident sample of special (high security) hospital patients, we examined the association between mental disorder and violence. METHOD: A record survey of all 1740 patients resident at any time between 1 January and 30 June 1993, inclusive, and, for most, the official criminal record. RESULTS: 1015 patients (58%) had functional psychosis, one-quarter of whom also had an independent personality disorder; 461 (26%) had personality disorders uncomplicated by psychosis, and 264 (16%) had learning disabilities. Pre-admission substance misuse, which was probably under-recorded, had been most common among those with psychosis and an independent personality disorder. Less than 10% had never been convicted of a criminal offence, although 25% had been admitted directly from other hospitals. Direct personal violence was more common among men, and fire-setting among women. Schizophrenia was most strongly associated with personal violence. More than 75% of those with a psychosis were recorded as being driven to offend by their delusions. In the absence of delusions, hallucinations had no such effect. CONCLUSIONS: For people with personality disorder better clinical descriptions seem essential. For people with a pure psychosis, as symptoms were usually a factor driving the index offence, treatment appears as important for public safety as for personal health.

Adult↗
PubMed1998

The use of cold compression dressings after total knee replacement: a randomized controlled trial.

This prospective, controlled study compared cold compressive dressings with wool and crepe in the postoperative management of patients undergoing total knee replacement (TKR). Forty TKR patients were assessed for blood loss, pain, swelling, and range of motion. Patients in the cold compression group had less blood loss through suction drainage (982 mL versus 768 mL). A higher proportion of patients in the treatment group did not require blood transfusion postoperatively. Mean opiate requirements were lower in the cold compression group (0.57 versus 0.71 mg/kg/48 hours). The cold compression device appeared to reduce blood loss and pain following TKR.

Aged↗
PubMed1998

Effect of the British warning on contraceptive use in the General Medical Service in Ireland.

In October 1995 the UK Committee of Safety of Medicine (CSM) issued a warning about the safety (thromboembolic disease) of the third generation oral contraceptive steroids (OCS) recommending a switch to older agents except where women were intolerant of first and second generation OCS. Advice by the Irish regulatory authority (Irish Medicines Board) did not recommend such a switch. This pill scare lead to some UK users stopping OCS mid-cycle and a rise subsequently in abortions and pregnancies was noted. To determine whether local or UK advice was followed we obtained data from the General Medical Service (GMS) Scheme on the use of contraceptive steroids prescribed before and after the CSM's warning. The results show a clear shift from usage of the third generation OCS to the second generation OCS and norgestimate-containing OCS. We have also noted a marked fall in the overall use of the combined OCS, a trend that was noted in the U.K. It is clear that prescribers and pill users were influenced more by advice from the UK than by Irish regulatory authority. There is now a centralised European mechanism to licence drugs in the European Union (EU). We need to develop an EU perspective to issues of drug safety, as constituent nations are no longer isolated islands.

Adolescent↗
PubMed1998

Trial by media: the case of the worn hip prostheses.

Another example of a medical device failing to produce a uniformly satisfactory performance is being widely discussed in the media. The controversy it arouses reduces patient confidence in the industry and calls into question the value of some technical developments and the effectiveness of regulatory procedures. Some of the generic issues arising from this case are discussed in this article.

Health Education↗