Search PubMed⌕ Search

Biomedical subjects

L Black

Publications and source records attributed to L Black.

At least 19 recordsLinked to original sources
PubMed2006

Predictive input parameters for enteric virus presence at the inlet of a potable water supply.

Kentucky river water samples were collected at the input of a potable water supply weekly, for a period of two years. Eighteen parameters were analysed and/or recorded for each weekly observation. The variables were of a physical, chemical and biological nature. Enteric virus presence was detected by cell culture analysis from approximately 200 L samples of river water. A database of 108 observations was assembled. Of these only 100 complete observations were used for the modelling analysis. Model input parameters were selected solely based on their statistical significance in forward, backward and stepwise selection procedures. Multivariate logistic regression (MLR) was used to determine the relative significance of the input parameters for predicting the presence or absence of enteric virus. The final, best-fit MLR model that used log-transformed values for enterococci, the AC/TC ratio, faecal coliforms (FC) and temperature demonstrated 82.5 and 81.4% sensitivity and specificity, respectively.

Enterovirus↗
PubMed2005

Racial disparities in the use of surgical treatment for intractable temporal lobe epilepsy.

OBJECTIVE: To compare the use of surgical treatment for epilepsy among different ethnic and racial groups with surgically remediable temporal lobe epilepsy (TLE). METHODS: The authors used multiple logistic regression analysis to model the use of anterior temporal lobectomy in a cross-sectional study of video-EEG monitoring discharge data among residents of Alabama and surrounding states discharged from the University of Alabama at Birmingham Hospital between July 1998 and January 2003 with a primary diagnosis of TLE. RESULTS: Of 432 patients diagnosed with TLE, 130 had evidence of mesial temporal sclerosis on MRI studies. Seventy patients underwent surgery; African Americans were less likely than non-Hispanic whites to undergo surgical treatment (odds ratio, 0.3; 95% CI, 0.2 to 0.8). After potential demographic (age, education, and sex), socioeconomic, medical insurance coverage, and clinical confounders (bitemporal seizure onset) were controlled, African Americans had a 60% less chance to receive surgery than non-Hispanic whites. CONCLUSIONS: There are disparities in the use of surgical treatment for temporal lobe epilepsy. Race appears to be an influential factor related to such disparities.

Adult↗
PubMed2004

ToF-SIMS depth profiling analysis of the uptake of Ba2+ and Co2+ ions by natural kaolinite clay.

The sorption behavior of Ba(2+) and Co(2+) ions on a natural clay sample rich in kaolinite was studied using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Depth profiling at 10-A steps was performed up to a 70-A matrix depth of the clay prior to and following sorption. The results showed that Co(2+) is sorbed in slightly larger quantities than Ba(2+), with significant numbers of ions fixed on the outermost surface of the clay. Depletion of the ions K(+), Mg(2+), and Ca(2+) from the clay lattice was observed to accompany enrichment with Co(2+) and Ba(2+) ions. The data obtained using X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM) indicated insignificant structural and morphological changes in the lattice of the clay upon sorption of both Ba(2+) and Co(2+) ions. Analysis using energy dispersive X-ray spectroscopy (EDS) showed that the average atomic percentage (+/-S.D.) of Ba and Co on kaolinite surface were 0.49 +/- 0.11 and 0.61 +/- 0.19 , respectively, indicating a limited uptake capacity of natural kaolinite for both ions.

Aluminum Silicates↗
PubMed2001

High levels of monoaromatic compounds limit the use of solid-phase microextraction of methyl tert-butyl ether and tert-butyl alcohol.

Recently, two papers reported the use of solid-phase microextraction (SPME) with poly(dimethylsiloxane)(PDMS)/Carboxen fibers to determine trace levels of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (tBA) in water. Attempts were made to apply this technique to the analysis of water samples containing high levels of benzene, toluene, ethylbenzene, xylenes, and trimethylbenzenes (BTEXsTMBs) as would be expected at leaking underground storage tank sites. It was found that when the sample contained total aromatic compounds above 1 ppm, the response of the internal standards, deuterated MTBE and tBA, dropped by more than 65%. As this decrease in internal standard peak area was unacceptable, a static headspace method was used instead. This headspace method was used successfully to analyze groundwater from 670 monitoring wells at 74 service stations located in the northeast United States. In these monitoring wells, 30% of the samples contained total BTEXsTMBs above 1 ppm. If the SPME method was used to analyze these samples, dilution of more than 200 samples would be required to minimize the adverse matrix effect that high aromatic content had on the internal standard peak area.

Carcinogens↗
PubMed2001

Efficacy, tolerability, and patient satisfaction with 50- and 100-mg sumatriptan tablets in those initially dissatisfied with the efficacy of 50-mg sumatriptan tablets.

BACKGROUND: Both 50- and 100-mg sumatriptan tablets are effective and well tolerated in the acute treatment of migraine. However, given a choice between the 2 doses, many patients in clinical practice and clinical studies prefer the 100-mg dose. OBJECTIVE: This study was designed to assess whether patients initially dissatisfied with the efficacy of 50-mg sumatriptan tablets would be satisfied with 100-mg sumatriptan tablets. METHODS: In phase 1 of the study, triptan-naive patients with migraine (International Headache Society diagnosis) received open-label treatment of 3 migraine attacks with 50-mg sumatriptan tablets. At the end of phase 1, those who were dissatisfied with the efficacy but satisfied with the tolerability of 50-mg sumatriptan tablets entered phase 2 and were randomized in a double-blind, parallel-group fashion to receive either 50- or 100-mg sumatriptan tablets for the treatment of 3 attacks. Patients who were satisfied with the efficacy or dissatisfied with the tolerability of the 50-mg tablets in phase 1 were given the option of continuing open-label treatment with 50-mg sumatriptan tablets in phase 2. The primary end point was the percentage of patients satisfied with medication at the end of phase 2 double-blind treatment. Patient satisfaction with specific medication attributes was assessed using the Patient Perception of Migraine Questionnaire. RESULTS: Seven hundred twenty-two patients were enrolled in phase 1 of the study (the intent-to-treat population), 609 of whom had evaluable satisfaction data at the end of open-label treatment. Three hundred twenty-six (54%) of these patients were satisfied with 50-mg sumatriptan tablets, whereas 283 (46%) were not satisfied. Among those who were dissatisfied, lack of efficacy was cited as the sole reason for dissatisfaction by 242 (86%). Two hundred thirty-one of those who were dissatisfied with efficacy only and wished to continue the study were randomized to double-blind treatment with either 50-mg sumatriptan tablets (n = 123; 82% female, 18% male; mean age, 37.6 years) or 100-mg sumatriptan tablets (n = 108; 86% female, 14% male; mean age, 36.0 years). The remaining 310 patients elected to continue open-label treatment with 50-mg sumatriptan tablets. At the end of double-blind treatment, 64 of 101 patients (63%) in the 100-mg group indicated that they were satisfied with treatment, compared with 55 of 113 (49%) in the 50-mg group (P = 0.031). Across the 3 attacks treated in the double-blind phase. headache relief 2 hours postdose was reported by 47% to 53% of patients in the 50-mg group and 45% to 60% of patients in the 100-mg group. The overall incidence of patients reporting > or =1 adverse event was 19% (23/123) in the 50-mg group and 22% (24/108) in the 100-mg group. CONCLUSIONS: For most patients, 50 mg is the appropriate starting dose of sumatriptan tablets. In patients who experience inadequate relief with 50 mg, increasing the dose to 100 mg is an appropriate therapeutic option.

Adult↗
PubMed2001

Sumatriptan: economic evidence for its use in the treatment of migraine, the Canadian comparative economic analysis.

The objective of this study was to evaluate economic and health effects of sumatriptan relative to customary therapy in Canada. The relationship between treatment and functionality was established based on analysis of existing data from a multinational study. A Monte Carlo model was developed to simulate 1 year for each of customary therapy and six sumatriptan formulations. Costs are expressed in 1998 Canadian dollars. Sumatriptan is expected to reduce the time spent with migraine symptoms and resulting time lost. Under customary therapy, the annual cost of lost time is estimated at pound908 ($1973). With sumatriptan, these costs ranged from pound406 ($882) with subcutaneous sumatriptan to pound577 ($1254) with nasal sumatriptan 10 mg, saving pound331-502 ($719-1091) in the annual cost of time lost. All these benefits are expected to be obtained at an additional drug cost ranging from pound869 ($1889) for subcutaneous sumatriptan to pound278 ($605) for sumatriptan suppository. The cost of sumatriptan treatment is significantly offset by a substantial reduction of costs associated with time lost due to migraine symptoms.

Canada↗
PubMed2001

Treatment of migraine in Canada with naratriptan: a cost-effectiveness analysis.

OBJECTIVE: To evaluate the cost-effectiveness of naratriptan for the treatment of migraine in Canada. BACKGROUND: The substantial disability brought on by migraine, coupled with the high prevalence of this disorder, leads to substantial costs. Naratriptan is a newly developed triptan shown to be effective in the treatment of migraine. METHODS: Monte Carlo modeling techniques were used to simulate the experience of Canadian migraineurs over the course of 1 year. Data from a multinational study comparing oral naratriptan 2.5 mg to customary therapies were used in the cost-effectiveness analysis. RESULTS: Naratriptan leads to an annual reduction in symptom duration of 225 hours compared to customary therapy not including other triptans. Reductions in lost productivity yield savings of Can $390 (1998 Canadian dollars) relative to customary therapy, which exceed the increase in drug costs resulting in overall savings of Can $109 per year. CONCLUSIONS: The use of naratriptan in the treatment of migraine is an economically attractive option, leading to savings in overall costs. Increases in drug costs seem acceptable in light of reductions in symptom duration.

Canada↗
PubMed2000

Homocysteine, folate, vitamin B-12 and vitamin B-6 in patients receiving antiepileptic drug monotherapy.

We hypothesized that elevated plasma homocysteine concentrations (hyperhomocysteinemia) exist in patients receiving antiepileptic drugs (AED), and a long-term administration of AED may result in an increased risk of occlusive vascular disease in these patients. A total of 62 patients who received AED monotherapy (phenytoin, lamotrigine, carbamazepine or valproate) participated in this study. Blood concentrations of homocysteine, folate, vitamin B-12 and pyridoxal-5'-phosphate (PLP, a coenzyme form of vitamin B-6) were measured, and thermolabile genotypes of 5, 10-methylenetetrahydrofolate reductase (MTHFR) were also determined. Of 62 patients, only seven (11.4%) had hyperhomocysteinemia. Of 20 patients who received phenytoin, three (15.0%) had hyperhomocysteinemia, whereas 85% of these had plasma folate concentrations below the normal range. However, erythrocyte folate concentrations were abnormally low in only 25% of the patients who received phenytoin. Valproate administration increased serum vitamin B-12 concentrations. Over 55% of the entire patients had PLP concentrations below the normal range, although the reason is unknown. Only three patients had the homozygous thermolabile genotype of MTHFR; therefore, meaningful statistical analysis was not possible in this study. However, one patient with homozygous genotype who received phenytoin therapy had hyperhomocysteinemia with poor folate nutritional status, and the other two had normal homocysteine concentrations with normal folate status. Our data suggest that hyperhomocysteinemia is not a serious clinical concern in epileptic patients when folate nutriture is adequate.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗
PubMed2000

The migraine ACE model: evaluating the impact on time lost and medical resource Use.

OBJECTIVE: To describe the Migraine Adaptive Cost-Effectiveness Model in the context of an analysis of a simulated population of Canadian patients with migraine. BACKGROUND: The high prevalence of migraine and its substantial impact on patients' ability to function normally present a significant economic burden to society. In light of the recent availability of improved pharmaceutical treatments, a model was developed to assess their economic impact. METHODS: The Migraine Adaptive Cost-Effectiveness Model incorporates the costs of time lost from both work and nonwork activities, as well as medical resource and medication use. Using Monte Carlo techniques, the model simulates the experience of a population of patients with migraine over the course of 1 year. As an example, analyses of a Canadian population were carried out using data from a multinational trial, surveys, national statistics, and the available literature. RESULTS: Using customary therapy, mean productivity losses (amounting to 84 hours of paid work time, 48 hours of unpaid work time, and 113 hours of leisure time lost) were estimated to cost $1949 (in 1997 Canadian dollars) per patient, with medical expenditures adding an average of $280 to the cost of illness. CONCLUSIONS: With customary treatment patterns, the costs of migraine associated with reduced functional capacity are substantial. The migraine model represents a flexible tool for the economic evaluation of different migraine treatments in various populations.

Adolescent↗
PubMed2000

Effect of the administration of recombinant activated factor VII (rFVIIa; NovoSeven) in the management of severe uncontrolled bleeding in patients undergoing heart valve replacement surgery.

Recombinant activated factor VII (rFVIIa; NovoSeven, Novo Nordisk A/S, Bagsvaerd, Denmark) is being increasingly used to secure haemostasis in difficult clinical situations. The role of rFVIIa in the treatment of patients undergoing open-heart surgery for valvular heart disease was evaluated in an open pilot study. Study objectives included evaluation of blood loss, haemostatic effect and safety and laboratory parameters following rFVIIa administration. To date, we have treated five patients (one child aged 2.5 years and four adults) undergoing surgical procedures including arterial switch, closure of atrial septal defect and De Vega's procedure (mitral valve replacement with tricuspid valve repair). Four patients received rFVIIa intraoperatively, while the fifth received it postoperatively. Satisfactory haemostasis was achieved with a single dose (30 microg/kg) of rFVIIa. Four hours after treatment mean blood loss was 262.5 ml for adults (220-334 ml) and 85 ml for the child. No significant adverse events were reported. Laboratory parameters indicated a mean 18.5-fold (range 3.7-42) increase in FVII levels at 30 min postinjection and a mean reduction of 12 s (range 3-39 s) in prothrombin time. In conclusion, rFVIIa represents an effective and well-tolerated treatment for serious bleeding episodes both during cardiac surgery and postoperatively.

Adult↗
PubMed1999

Indirect costs of migraine in a managed care population.

Migraine is a highly prevalent condition that commonly affects individuals during their most productive years. The aggregate cost of providing healthcare for persons with migraine is substantial, but the economic consequences of lost and reduced productivity among this population are greater. This paper presents estimates of the annual indirect costs associated with migraine in a managed-care population. Our estimates include workplace and domestic productivity losses for persons employed outside the home as well as those persons engaged exclusively in domestic production or who are unable to work. We find that migraine is associated with annual indirect costs for men and women, respectively, of $4,548 and $4,897 in 1990 dollars, and that indirect costs increase with headache severity. Further research should continue to emphasize headache's effect on domestic production in order to avoid bias in measuring the economic effect of headache on women.

Adult↗
PubMed1998

Thumb joint flexion. What is normal?

The purpose of this study was to measure the amount of active flexion from a neutral position in normal thumb metacarpophalangeal and interphalangeal joints and compare the results with previously published reports. One hundred and nineteen subjects (238 thumbs) volunteered to have active flexion of the metacarpophalangeal (MP) and interphalangeal (IP) joints of the thumb measured with a computerized Greenleaf goniometer by a certified hand therapist. The mean MP flexion was 59 degrees and IP flexion was 67 degrees. The results of this study suggest that the accepted normal values of thumb flexion should be reconsidered, particularly as a guide for determining impairment.

Adolescent↗
PubMed1997

Severe aquired haemophilia A treated with recombinant factor VIIa.

Acquired haemophilia can be associated with various conditions including pregnancy, autoimmune diseases and lymphoproliferative disorders, though often no underlying cause is found. It often presents with a rapid onset of muscle bleeding and involves the IgG antibody. It may be treated with human or porcine factor VIII (FVIII), prothrombin complex concentrates, factor IX (FIX) complex concentrates, factor VIIa (FVIIa) or by immunosuppression. We report a case of acquired haemophilia in a 40-year-old woman diagnosed following laparotomy. She was treated unsuccessfully using human FVIII and cryoprecipitate, porcine FVIII and FIX complex concentrate, before being treated with recombinant FVIIa (NovoSeven, Novo Nordisk). On treatment with recombinant FVIIa, bleeding stopped rapidly with no side-effects and the abdominal haematoma was evacuated with minimal post-operative bleeding.

Adult↗
PubMed1997

Occipital lobe developmental malformations and epilepsy: clinical spectrum, treatment, and outcome.

PURPOSE: Cortical developmental malformations (CDM) are increasingly recognized in association with epilepsy. We describe 10 patients (age range 14-35 years) with symptomatic occipital lobe epilepsy and CDM. METHODS: Neurologic, neuroophthalmologic and electrophysiologic studies were performed. Patients had MRI, SPECT, and in some cases intracranial EEG investigators. RESULTS: Mean age of seizure onset was 8 years. We noted strong correlations between the presence of visual auras, the scalp EEG pattern, and the subtype of underlying pathology. Magnetic resonance imaging (MRI) showed CDM in all patients, with polymicrogyria and focal dysplasia being the most frequent malformations. Despite the presence of occipital lobe structural malformations in all patients, visual field deficits were present in only 2. Those who underwent cortical resections were seizure-free or showed major improvement at a mean follow-up of 3.5 years. CONCLUSIONS: Intracranial stimulation studies and the low frequency of pre- and postoperative deficits suggest that some degree of cortical visual reorganization may occur in patients with occipital lobe malformations. Occipital lobe CDM should be sought as a cause of symptomatic occipital lobe epilepsy even though they may become symptomatic after childhood.

Adolescent↗
PubMed1997

Patient-validated content of epilepsy-specific quality-of-life measurement.

PURPOSE: To study the effects of epilepsy from the patients' perspective and assist determination of content validity of health-related quality-of-life (HRQOL) measures. METHODS: We asked 81 consecutive patients with moderately severe epilepsy to list in order of importance their concerns of living with recurrent seizures. To minimize investigator bias, patients completed the procedure in a private setting without staff involvement. RESULTS: Twenty-four distinct domains were generated by the patients. Concerns about driving (64%), independence (54%), employment (51%), social embarrassment (36%), medication dependence (33%), mood/stress (32%), and safety (31%) each were listed by > 30% of patients. Driving was listed as the most important concern by 28% of patients, followed by employment (21%), independence (9%), safety (6%), antiepileptic-drug side effects (5%), seizure unpredictability (5%), and seizure aversion (5%). CONCLUSIONS: The effect of epilepsy on HRQOL is not vague or obscure from the patients' perspective but is defined by a limited number of domains. Independence is an important concern that may not be evaluated adequately by currently available HRQOL instruments.

Activities of Daily Living↗
PubMed1996

Qualitative MRI segmentation in mesial temporal sclerosis: clinical correlations.

Magnetic resonance imaging (MRI) is reliable and sensitive in the detection of mesial temporal atrophy in patients with temporal lobe epilepsy. We investigated the MRI patterns of atrophy in 47 patients with histologically confirmed hippocampal sclerosis and correlated the imaging findings to the clinical features and surgical outcome. One hundred percent of patients had hippocampal body atrophy, 70% had hippocampal tail atrophy, 23% had amygdala atrophy, and 10% had focal hippocampal body atrophy without other segmental involvement. Correlative analysis of the segmented MRI findings with other clinical variables, including a previous history of childhood febrile convulsions, showed no significant associations except for younger age of seizure onset associated with hippocampal tail atrophy (p <0.03). No associations between surgical outcome and the patterns of mesial temporal atrophy were detected. Our results demonstrate that variable patterns of atrophy exist in mesial temporal atrophy, but invariably atrophy involves the hippocampal body segment. Segmental MRI analysis in mesial temporal atrophy provides added useful diagnostic information.

Adolescent↗
PubMed1996

Let us pray.

Explore the source record for details and available documents.

Female↗