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Biomedical subjects

D Smith

Publications and source records attributed to D Smith.

At least 1,333 records · Page 74Linked to original sources
PubMedDate not supplied

Impact of triiodothyronine on the survival of high-risk patients undergoing open heart surgery.

Experimental and clinical studies have shown the beneficial effects of triiodothyronine (T3) following myocardial revascularization on cardiopulmonary bypass (CPB). In this study, open-label T3 was administered to 68 high-risk patients undergoing open heart surgery. The New Jersey Risk Assessment was used to calculate the preoperative estimated surgical mortality. A loading dose of T3 was administered: (a) at release of the aortic cross-clamp, (b) whenever the patient became CPB dependent, (c) if the patient exhibited low cardiac output after discontinuing CPB and (d) as pretreatment before initiating CPB. All therapeutic modalities were followed by a continuous T3 infusion. Following T3 therapy, CPB was discontinued in all patients. Based upon discriminant analysis, a total of 26 deaths were expected from the entire group, but only 7 patients died, therefore, the observed mortality was reduced by 72% (p < 0.007). The use of T3 had a major impact on reducing surgical mortality, and may be advocated as a new therapeutic modality in patients with high estimated mortality undergoing open heart surgery.

Adult↗
PubMedDate not supplied

p53 gene product in pleural effusions. Practical use in distinguishing benign from malignant cells.

OBJECTIVE: To determine the utility of positive p53 immunostaining as an adjunct in the diagnosis of malignancy in pleural effusions, we reviewed 103 effusions representing the typical range of diagnoses encountered in the evaluation of pleural fluid cytology. STUDY DESIGN: Immunohistochemistry was performed on paraffin-embedded cell blocks using a monoclonal antibody to the p53 suppressor gene product clone BP53-12 and a standard avidin-biotin complex technique with a citrate buffer antigen retrieval solution. RESULTS: Forty-one of 75 effusions with an unequivocal cytologic diagnosis of malignancy were immunopositive for p53 protein (55%). One of nine effusions cytologically interpreted as showing reactive mesothelial cells showed immunopositivity; that case was subsequently diagnosed as a mesothelioma on pleural biopsy. Nineteen cases were interpreted as suspicious for malignancy. Of these, 16 were negative, and 3 were positive for p53 protein. Of the three positive cases, two showed the presence of non-small cell and poorly differentiated large cell carcinoma. CONCLUSION: These findings suggest that p53 protein immunostaining is relatively sensitive and highly specific in differentiating benign mesothelial cells from malignant cells in pleural effusions. While negative p53 protein immunostaining does not exclude malignancy, positive staining in reactive or suspicious cells warrants further diagnostic evaluation of the patient.

Evaluation Studies as Topic↗
PubMedDate not supplied

Ambulatory blood pressure comparison of the anti-hypertensive efficacy of fixed combinations of irbesartan/hydrochlorothiazide and losartan/hydrochlorothiazide in patients with mild-to-moderate hypertension.

This study examined whether the greater anti-hypertensive efficacy of irbesartan monotherapy over losartan monotherapy extends to the respective fixed-dose combinations with hydrochlorothiazide (HCTZ) in patients with mild-to-moderate hypertension. Patients were treated with either irbesartan 150 mg/HCTZ 12.5 mg or losartan 50 mg/HCTZ 12.5 mg over a 4-week period. Twenty-four hour daytime and night-time mean blood pressure (BP), BP load and duration of action were assessed using ambulatory BP monitoring. Both treatment regimens significantly reduced BP from baseline for all efficacy variables assessed. A significant difference was noted in adjusted mean changes from baseline in 24-h ambulatory diastolic BP with irbesartan/HCTZ versus losartan/HCTZ. Reduction in diastolic load was significantly greater with irbesartan/HCTZ than with losartan/HCTZ as was mean ambulatory systolic BP during the last 4 h of the dosing interval. Both regimens were well tolerated, with no significant differences in terms of adverse event profile observed. Irbesartan 150 mg/HCTZ 12.5 mg resulted in greater reductions in ambulatory BP than losartan 50 mg/HCTZ 12.5 mg.

Adult↗
PubMedDate not supplied

A randomized trial of nelfinavir, ritonavir, or delavirdine in combination with saquinavir-SGC and stavudine in treatment-experienced HIV-1-infected patients.

PURPOSE: To evaluate the 24-week impact of saquinavir-enhancing antiretroviral therapy on viral replication in patients previously treated with nucleoside analogues with or without prior saquinavir hard-gel capsules (HGC). METHOD: Patients were randomized in three groups to receive the following: Group 1-nelfinavir (750 mg tid), saquinavir soft-gel capsule (SGC) (800 mg tid), and stavudine (40 mg bid); Group II-ritonavir (400 mg bid), saquinavir-SGC (400 mg bid), and stavudine (40 mg bid); or Group III-delavirdine (400 mg tid), saquinavir-SGC (800 mg tid), and stavudine (40 mg bid). Viral loads, CD4 count, and safety were assessed over a 24-week period with an additional 6-month follow-up. RESULTS: 73 patients received randomized therapy; 14 of whom were SQV naïve, with a median baseline viral load of 3.6 log(10) and a CD4 count of 370 cells/mm(3). By 6 months, the median decreases in plasma viral loads were 0.26, 0.71, and 0.29 log(10) copies/mL for groups I, II, and III, respectively. The median increases in CD4 counts, for groups I, II, and III, were 52, 40, and 69 cells/mm(3) at 6 months, respectively. Changes in viral load and CD4 counts at 6 months and 1 year were not significantly different between the treatment groups. More patients discontinued therapy in the ritonavir arm (35%) for drug intolerance or toxicity compared to either the nelfinavir or delavirdine arms (15% and 5%, respectively). In a multivariate analysis, baseline viral load, younger age, and baseline saquinavir resistance were significantly associated with detectable viral load at 24 weeks. CONCLUSION: The use of antiretroviral agents that pharmacokinetically boost saquinavir levels has a modest benefit in saquinavir-experienced patients.

Adult↗
PubMedDate not supplied

Baseline antiretroviral drug susceptibility influences treatment response in patients receiving saquinavir-enhancing therapy.

PURPOSE: To relate baseline plasma HIV genotypic and virtual phenotypic antiretroviral drug susceptibility to subsequent virological response in patients receiving saquinavir (SQV)-enhancing therapy. Individuals were randomized to receive stavudine (d4T), SQV, and one of ritonavir, nelfinavir, or delavirdine to enhance SQV blood levels. METHOD: The protease and reverse transcriptase baseline sequences of 31 treatment-experienced patients were analyzed by genotype and virtual phenotype and were related to viral load at weeks 12 and 24. Genotypic resistance to SQV was defined by the presence of G48V and/or L90M mutations in the protease gene. Potential cross-resistance to d4T in zidovudine (ZDV)-experienced individuals was defined by the presence of thymidine-associated mutations in the reverse transcriptase gene. RESULTS: ZDV-associated mutations did not affect the virological response at 24 weeks. Individuals who were sensitive to SQV at baseline as determined by either genotyping or virtual phenotyping showed a greater decrease in viral load at week 24 than those resistant to SQV, irrespective of treatment arm. By genotyping, SQV-sensitive individuals had a median log decrease of 1.12 compared to 0.32 for those individuals who were SQV resistant. By virtual phenotyping, SQV-sensitive individuals had a median log decrease of 1.0 compared to a rise of 0.08 in resistant individuals. CONCLUSION: Thymidine analogue-associated mutations at baseline did not influence the response to subsequent therapy involving d4T. Individuals who were sensitive or resistant to SQV by genotyping or virtual phenotyping responded to SQV-enhancing regimens, but the virological response was greater in those who were sensitive.

Anti-HIV Agents↗
PubMedDate not supplied

Stereotactic computer-assisted navigational sinus surgery: accuracy of an electromagnetic tracking system with the tissue debrider and when utilizing different headsets for the same patient.

The InstaTrak system by Visualization Technologies, Inc. (Woburn, MA) has recently introduced attachments that can be utilized to localize the tip of the XPS Straightshot debrider (Xomed Industries, Jacksonville, FL) during image-guided surgery. The accuracy of these newer attachments has not been objectively tested in a clinical setting. Our primary objective was to compare the actual instrument (XPS debrider tip) location with its computer screen location in the coronal, sagittal, and axial views. This was considered to be the "accuracy" of the instrument being tested. We secondarily compared its accuracy with the accuracy of the 0 degree and 45 degrees curved localizing aspirators in a prospective study. The manufacturer also recommends that the same headset used during scanning be utilized during surgery. A second objective therefore was to determine if a headset other than the one used during CT scanning could be used intraoperatively with an acceptable level of accuracy. Accuracy of the instruments between the patients' own headset (used during CT scanning) and a generic or research headset (not used during scanning) was compared intraoperatively. The third and final objective was to determine if the same headset could be used repeatedly with an acceptable level of accuracy. Generic "research" headsets were therefore utilized for a total of five surgeries per headset and visual accuracy between the multiply utilized research headsets and the patients' own headsets was recorded and compared. Anatomic localization accuracy was 1.06 mm for the XPS debrider, 0.89 mm for the 0 degree aspirator, and 1.05 mm for the 45 aspirator when the patients own headset was utilized. When the research (generic) headset was utilized the respective values were 0.69 mm for the debrider, 0.77 mm for the 0 degree aspirator, and 0.99 mm for the 45 degrees aspirator. With multiple utilization of a single headset, there was no significant loss in accuracy. In conclusion, the accuracy of the newly marketed attachment for the debrider was found to be comparable to the standard aspirators. Accuracy remained acceptable when a headset other than the one used during CT scanning was used intraoperatively. No loss in accuracy was noted when a headset was utilized more than once.

Debridement↗
PubMedDate not supplied

A spatial arrangement memory testing unit.

The Spatial Arrangement Memory Testing Unit is a new apparatus which has been designed to provide a low-cost, portable instrument for assessing visuo-spatial memory performance. It is particularly useful for aiding diagnosis and planning rehabilitation programmes for patients that have suffered brain damage. The application of microprocessor technology has allowed a flexible programmable approach to the operation of the equipment. The system uses a dedicated Zilog Z80 microprocessor with associated software held in EPROM. An integral printer is used to provide a permanent record of patient performance.

Biomedical Engineering↗
PubMedDate not supplied

Lead poisoning from drinking Kombucha tea brewed in a ceramic pot.

Kombucha tea is an alternative therapy that is gaining popularity as a remedy for a diverse range of ailments. We report two cases of symptomatic lead poisoning requiring chelation therapy in a married couple who had been drinking Kombucha tea for six months, brewing the tea in a ceramic pot. We postulate that acids in the tea eluted lead from the glaze pigment used in the ceramic pot, in a manner analogous to elution of lead from crystal decanters by wine and spirits.

Ceramics↗
PubMedDate not supplied

A randomised, double-blind study of itraconazole versus placebo in the treatment and prevention of oral or oesophageal candidosis in patients with HIV infection.

HIV-infected patients presenting with oral or oesophageal candidosis were randomised to four weeks treatment with itraconazole 200 mg, followed by itraconazole or matching placebo for a prophylaxis phase of 24 weeks. Clinical and mycological evidence of candidosis infection was assessed on a four-weekly basis. Seventy patients were enrolled, of whom 50 completed 28 days of itraconazole therapy; 74% (37 patients) were clinically cured and 40% were also mycologically cured. Fifteen patients were withdrawn for a variety of reasons including non-compliance, adverse events and the use of excluded medications. Forty-four patients were enrolled in the prophylactic phase. There were significantly more relapses of candidosis, and time to candidosis was significantly shorter in the placebo group than in the itraconazole treated group (p = 0.0001). Itraconazole 200 mg daily is effective and well tolerated for the treatment and prevention of oral and oesophageal candidosis in HIV-infected patients.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Myocardial viability--mechanisms of reversible myocardial dysfunction and diagnosis in coronary artery disease.

The natural history of ischaemic myocardium and numerous revascularisation studies have proved that it is clinically important to distinguish viable but dysfunctional myocardium from irreversibly injured muscle in patients with coronary disease. A large variety of invasive and non-invasive methodologies are available for the detection of myocardial viability. This review focuses on the value and limitations of the current diagnostic approach to the recognition of stunned and hibernating myocardium in the light of the current understanding of their pathophysiological mechanisms.

Coronary Artery Disease↗