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Biomedical subjects

B Alexander

Publications and source records attributed to B Alexander.

At least 127 records · Page 7Linked to original sources
PubMed1988

Antacids reduce Campylobacter pylori colonization without healing the gastritis in patients with nonulcer dyspepsia and erosive prepyloric changes.

Antral biopsy specimens from 89 consecutive patients with nonulcer dyspepsia and erosive prepyloric changes included in a prospective, randomized, double-blind 4-wk study of the effect of an aluminum-magnesium antacid (120 mmol/day) or pirenzepine (50 mg b.i.d.) vs. placebo were examined histologically. Campylobacter pylori (CP) was found by light microscopy of silver-stained sections in 25 patients (28%). Campylobacter pylori-positive patients were on average older than CP-negative patients (p = 0.02). There was a strong association between CP colonization and acute inflammation (p less than 0.001), both being rare in the absence of chronic inflammation. During treatment with antacids, the density of CP decreased (p less than 0.001) without any improvement of the inflammatory reaction. On the contrary, the number of patients with gastritis tended to increase after antacids as compared with placebo (p less than 0.10). A separate analysis showed no symptomatic effect of the drugs. Thus, neither nonulcer dyspepsia nor erosive prepyloric changes are strongly associated with antral CP colonization or acute inflammation. Aluminum-magnesium antacids may suppress antral CP infection without healing the gastritis or relieving symptoms.

Adult↗
PubMed1988

A frequency matrix for probabilistic identification of some bacilli.

A matrix comprising frequencies for positive results for 44 Bacillus taxa for 30 characters has been constructed. The 44 taxa include most of the common species and several clusters of environmental isolates including those described as B. firmus-B. lentus intermediates. The tests, which were chosen for their high diagnostic value, included some of the traditional tests used for identification of bacilli supplemented with a range of sugar fermentations and other characterization tests. The matrix was evaluated by identifying hypothetical median organisms, cluster representatives and a panel of 23 reference strains. All reference strains achieved Willcox probabilities above 0.995. Fifty-eight environmental isolates were also subjected to the 30 tests and identification was attempted. Forty-one strains (70%) achieved a Willcox probability greater than 0.95, which was considered an acceptable identification, and were assigned to 12 taxa. If the SE of taxonomic distance was also considered in the identification score (an acceptable value being less than 7.0), the number of acceptable identifications was reduced to 34 (59%). It was encouraging that bacteria from garden soils identified to the common species such as B. subtilis, B. cereus and B. licheniformis whereas some of the bacteria from an estuarine habitat were identified as species such as B. firmus which are normally identified with that habitat.

Bacillus↗
PubMed1988

Antipsychotics: how strict the formulary?

Seventeen antipsychotic medications are available in the U.S. Antipsychotic formulary considerations include relative efficacy, individual patient response, relative differences in adverse effects, dosage form availability, blood level monitoring, and generic availability. Chlorpromazine, thioridazine, haloperidol, and fluphenazine are recommended for formulary inclusion based on research and clinical considerations. A recommendation for managing a patient receiving a nonformulary antipsychotic is presented.

Antipsychotic Agents↗
PubMed1987

Rational use of antidepressants.

The key to the proper treatment of affective illness is a correct diagnosis of the subtype of depressive illness. Thus, primary treatment recommendations include the tricyclic antidepressants for a major depressive episode, electroconvulsive therapy for a major depressive episode with psychotic features, and monoamine oxidase inhibitors for dysthymic disorder and atypical depressive episodes. Nonresponding patients are treated with either lithium augmentation of TCA therapy or ECT. Second-generation antidepressants are recommended in situations where their adverse effect profiles offer significant advantages over TCAs in an individual patient. Maintenance antidepressant treatment may be necessary to prevent recurrent depressive episodes.

Antidepressive Agents↗
PubMed1986

Effects of smoking on nortriptyline plasma concentrations in depressed patients.

The pharmacokinetic parameters of half-life, volume of distribution, and steady-state nortriptyline plasma concentration normalized to a 100-mg/day maintenance dose were calculated in nine smokers and 15 nonsmokers. The mean normalized total nortriptyline concentration for the smokers of 118 +/- 33 ng/ml was significantly lower than the nonsmokers' mean value of 158 +/- 35 ng/ml. The mean normalized free plasma concentrations for the smokers of 11.4 +/- 3.5 ng/ml was not different from the nonsmokers' mean concentrations of 11.5 +/- 2.6 ng/ml. The smokers had a slightly higher percentage free drug values of 10.2 +/- 4.0% (p = 0.08) as contrasted to 7.4 +/- 1.5% free nortriptyline for the nonsmokers. The nortriptyline half-life figures for both the free and total drug concentrations did not differ. Multiple linear regression analysis utilizing age, smoking status, sex, liver function, and the presence or absence of enzyme-inducing or -inhibiting drugs as the potential independent variables and percentage free nortriptyline or total nortriptyline concentration as the dependent variable, found that smoking status explained 21% of the variation in the percentage free nortriptyline in the patients and 26% of the variation in the total nortriptyline concentrations. These preliminary data suggest that smokers ideally should be dosed at the lower end of the nortriptyline therapeutic range, whereas nonsmokers should be dosed at the upper end to maximize the antidepressant effect and minimize adverse effects.

Adolescent↗
PubMed1986

The utility of a single-point dosing protocol for predicting steady-state lithium levels.

Two methods for predicting steady-state serum lithium level were compared prospectively in in-patients suffering from affective disorder. A single-point prospective administration model that required a single 24-hour serum lithium level, following a test dose produced statistically similar predictions of the observed steady-state lithium levels as did a model that required 12- and 36-hour levels. However, the latter two-point method produced significantly more accurate predictions from clinical interpretation. Although the two-point approach is preferable, the single-point method is clinically acceptable if its limitations of accuracy are taken into consideration.

Adult↗
PubMed1986

Potential value of digital radiography. Preliminary observations on the use of dual-energy subtraction in the evaluation of pulmonary nodules.

The radiographic demonstration of calcification in a solitary pulmonary nodule renders the possibility of malignancy extremely unlikely, although rare exceptions have been reported. Conventional roentgenograms and tomograms sometimes provide inconclusive evidence although CT can be highly accurate in both identifying and quantifying calcium content. An alternative method is dual-energy subtraction utilizing scanned projection digital radiography. Forty-one patients with solitary (occasionally multiple) pulmonary nodules were examined with the technique, employing second-generation fan-beam equipment: 28 nodules or masses were noncalcified and 13 calcified. Of the former, 20 were pathologically proved, 16 being malignant and 4 benign (2 granulomas, 2 bronchiectasis); in 3 of the remaining 8, a presumptive diagnosis was reasonably certain (1 granuloma, 2 metastases), while in 5 the diagnosis was not made. In 8 of the 13 calcified lesions, the diagnosis can reasonably be regarded as confirmed as granulomas; 5 are being followed up with that presumptive diagnosis.

Adult↗
PubMed1986

Reliability of stroke volume to pulse pressure ratio for estimating and detecting changes in arterial compliance.

Total arterial compliance is an important haemodynamic variable which is difficult to measure in vivo. Using a Windkessel model, it can be determined from the ratio of the diastolic-decay time constant (tau) of the arterial system and the peripheral resistance. Using this technique, paired estimates of arterial compliance were determined in control and in mechanically produced low-compliance steady states. Since determination of compliance based on the three-element Windkessel model is tedious the same data were retrospectively analysed to evaluate the reliability of the stroke volume to pulse pressure ratio (SV:PP) for estimating and predicting changes in compliance. The linear correlation coefficient for 148 paired values of compliance determined by the two methods was r = 0.85, P less than 0.001. Both methods indicated similar values (mean +/- s.e.m.) for compliance in the control steady state: 0.35 +/- 0.01 ml/mmHg (using tau/R) versus 0.36 +/- 0.01 ml/mmHg (using SV:PP), P was NS, and both methods detected a significant decrease in compliance, P less than 0.001, in the low-compliance steady state: 0.18 +/- 0.01 ml/mmHg (using tau/R) and 0.21 +/- 0.01 ml/mmHg (using SV:PP). Thus, SV:PP compared with (tau/R) was a good index of compliance and changes in compliance and may prove to be a useful index for estimating compliance clinically.

Animals↗
PubMed1985

Malignant melanoma presenting as a mass obstructing the common bile duct.

Pathologic and computed tomographic correlation of an obstructing common bile duct mass, found to be malignant melanoma, is presented. No tumour was demonstrated elsewhere. Such a pattern of presentation has not previously been described in this condition. Malignant melanoma, even in the absence of disease elsewhere, should be considered in the differential diagnosis of such lesions seen on computed tomography.

Cholestasis, Intrahepatic↗
PubMed1985

Relationship of free nortriptyline levels to therapeutic response.

The relationship between the free plasma concentration of nortriptyline and therapeutic response was examined. Eighteen depressed inpatients were treated for 21 days with steady state total nortriptyline plasma concentrations between 50-150 ng/ml. Steady state free nortriptyline concentrations were measured. The therapeutic nortriptyline response was measured by administering the Hamilton and the Carroll Rating scales at day zero and day 21. Statistical relationships between free levels of drug and clinical response were found to be insignificant. Qualitative assessment of the data suggest that free serum levels of nortriptyline in excess of 10 ng/ml may have an inhibitory effect on clinical response.

Adolescent↗
PubMed1985

Switching monoamine oxidase inhibitors.

Substituting one monoamine oxidase inhibitor for another is recommended only after a drug-free interval to avoid hypertensive emergencies. The evidence and mechanism firmly supporting this caution is lacking. We report a case where monoamine oxidase inhibitors were substituted without apparent adverse consequences.

Adult↗
PubMed1984

Collaborative evaluation of the Abbott yeast identification system.

The Abbott yeast identification system (Abbott Laboratories, Diagnostics Division, Irving, Tex.) is a 24-h, instrumental method for identifying medically important yeasts, based on matrix analysis of 19 biochemical reactions and the germ tube test. The system was evaluated in two clinical laboratories by using 179 coded isolates, which included a high percentage of the less frequently encountered species. Based upon results with these coded isolates and from previously obtained laboratory data, the system software was adjusted and accuracy of the yeast identification system was further evaluated with 378 isolates from clinical sources. Of the 378 clinical yeast isolates tested, 364 (96%) were correctly identified with the Abbott system. Isolates were deliberately selected so that germ tube-positive isolates made up less than 10% of the clinical isolates tested.

Candida↗
PubMed1984

Reversible steroid dementia in patients without steroid psychosis.

Six patients developed dementia-like cognitive changes that appeared to result from administration of steroid medications. Four of the patients never showed symptoms of steroid psychosis; the remaining two continued to show steroid dementia well after their steroid psychoses had resolved. The dementia was characterized by deficits in memory retention, attention, concentration, mental speed and efficiency, and occupational performance. All six patients eventually recovered normal mental status following discontinuation or reduction of steroid medications. Larger prospective studies are needed to determine the prevalence and nature of the syndrome.

Adult↗
PubMed1984

Prospective evaluation of two lithium maintenance dose schedules.

A prospective method for recommending lithium carbonate maintenance doses for patients requiring the drug either prophylactically or for acute mania has been previously described. Of 18 patients who required prophylactic lithium levels between 0.40 and 0.89 mEq/liter, the maintenance dose equation achieved the predefined therapeutic range in 15 (83%) cases. Of 20 patients requiring lithium concentrations between 0.90 and 1.30 mEq/liter for the treatment of acute mania, 17 (85%) attained the therapeutic range after receiving the recommended maintenance dose. The authors discuss the factors that limit the usefulness of this prospective dosing protocol.

Adult↗