The FTA-ABS test: a diagnostic help or hindrance?

The fluorescent treponemal antibody absorption (FTA-ABS) test, an excellent confirmatory treponemal test, has been used increasingly for syphilis screening and case detection. To evaluate its performance as an initial test, we did Venereal Disease Research Laboratory (VDRL) slide and FTA-ABS tests on 1,043 patients suspected of having syphilis. When retested in both a local and a reference laboratory, sera from 226 patients with borderline or reactive results demonstrated interlaboratory consistency for the VDRL but not the FTA-ABS. Borderline FTA-ABS results correlated poorly with the diagnosis of syphilis in both laboratories; a reactive FTA-ABS test correlated well only in the reference laboratory. Performance of the test appeared to be diminished by its use in a low-prevalence population and by seemingly minor alterations in the test procedure at the local laboratory.     

Triiodothyronine and Thyroxine in Hyperthyroidism COMPARISON OF THE ACUTE CHANGES DURING THERAPY WITH ANTITHYROID AGENTS

In 66 untreated patients with hyperthyroidism, serum triiodothyronine (T(3)) and thyroxine (T(4)) concentrations were measured by immunoassay. The mean T(3) level was 478+/-28 ng/100 ml (all values mean+/-SEM) and the T(4) was 20.6+/-0.6 mug/100 ml. The serum T(4)/T(3) ratio by weight was 48+/-2 as opposed to a value of 71+/-3 in euthyroid adults. There was a significant inverse correlation of the T(4)/T(3) ratios with serum T(3) (r=0.77; P<0.01) but not with serum T(4)(r=0.21). These results suggested that relative overproduction of T(3) is consistently present in patients with hyperthyroidism.To examine the acute effects of various antithyroid agents on serum T(3) and T(4) concentrations, iodide, propylthiouracil (PTU), and methylmercaptoimidazole (MMI) were given alone to mine patients, and serial T(3) and T(4) measurements were made. There was an acute decrease in serum T(3) over the first 5 days in the three iodide and three PTU-treated patients which was greater than that seen in the MMI group. This suggested that PTU and MMI had different effects on T(3) production.To compare the effects of PTU and MMI under conditions in which thyroidal hormone release was minimized, these drugs were given in combination with iodide. The mean daily dosage of PTU was 827 (n=11) and of MMI was 88 (n=8). In the PTU+iodide group, the initial serum T(3) concentration was 586+/-61 ng/100 ml and decreased significantly to 326+/-41 on day 1 and to 248+/-21 on days 2 and 3, respectively, and did not change further on days 4 and 5. In the MMI + iodide group, basal serum T(3) was 645+/-90 ng/100 ml and decreased to 568+/-81, 452+/-73, and 344+/-51 on days 1, 2, and 3, respectively, and did not change thereafter. While the initial T(3) concentrations in serum were not different in the PTU and MMI groups, the T(3) concentrations in the PTU patients were significantly lower on days 1 and 2 and during the apparent plateau period on days 3-5. Serum T(4) concentrations decreased gradually in both groups, from 23.9+/-2.0 mug/100 ml, initially, to 17.5+/-1.6 on day 5 in the PTU group and from 22.0+/-2.6 to 14.6+/-2.0 in the MMI-treated patients. The T(4) values were not significantly different at any time. These changes resulted in increases in the serum T(4)/T(3) ratios in both groups, but these ratios were substantially higher in the patients treated with PTU + iodide. The initial serum T(4)/T(3) ratio was 43+/-3 and increased to 74+/-7 and 88+/-7 on days 1 and 2 in the PTU group, reaching a plateau value of 91+/-7 during days 3-5. Comparable values for MMI-treated patients were 35+/-2, 42+/-3, 52+/-6, and 54+/-3 during the plateau period.Previous investigations have shown that PTU inhibits T(4) deiodination in hyperthyroid patients and decreases T(3) production from T(4) in animals. The greater acute decrease in serum T(3) and the higher serum T(4)/T(3) ratios in the PTU-treated patients seems best explained by an inhibition of peripheral T(3) production by this agent. This conclusion is further supported by a direct relationship between the T(4)/T(3) ratio on days 3-5 and the dose of PTU administered. These results further suggest that both thyroidal and extrathyroidal pathways contribute substantially to the apparent overproduction of T(3) in hyperthyroidism.     

Plasma concentrations of inhaled budesonide and its effects on plasma cortisol are increased by the cytochrome P4503A4 inhibitor itraconazole

OBJECTIVE: Our objective was to examine the effects of itraconazole on the pharmacokinetics and cortisol-suppressant activity of budesonide administered by inhalation. METHODS: In a randomized, double-blind, 2-phase crossover study, 10 healthy subjects took 200 mg itraconazole or placebo orally once a day for 5 days. On day 5, 1 hour after the last dose of itraconazole or placebo, 1000 microg budesonide was administered by inhalation. Plasma budesonide and cortisol concentrations were measured up to 23 hours. RESULTS: Itraconazole increased the mean total area under the plasma concentration-time curve of inhaled budesonide 4.2-fold (range, 1.7-fold to 9.8-fold; P <.01) and the peak plasma concentration 1.6-fold (P <.01) compared with placebo. The mean terminal half-life of budesonide was prolonged from 1.6 to 6.2 hours (ie, 3.7-fold; range, 1.5-fold to 9.3-fold; P <.001) by itraconazole. The suppression of cortisol production after inhalation of budesonide was significantly increased by itraconazole as compared with placebo, as shown by a 43% reduction in the area under the plasma cortisol concentration-time curve from 0.5 to 10 hours (P <.001) and a 12% decrease in the cortisol concentration measured 23 hours after administration of budesonide, at 8 am (P <.05). CONCLUSIONS: Itraconazole markedly increased systemic exposure to inhaled budesonide, probably by inhibiting the cytochrome P4503A4-mediated metabolism of budesonide during both the first-pass and the elimination phases. This interaction resulted in enhanced systemic effects of budesonide, as shown by suppression of cortisol production. Long-term coadministration of budesonide and a potent CYP3A4 inhibitor may be associated with an increased risk of adverse effects of budesonide.     

Prediction of unfavorable outcomes in cryptococcal meningitis: results of the multicenter Infectious Diseases International Research Initiative (ID-IRI) cryptococcal meningitis study

Cryptococcal meningitis (CM) is mostly seen in immunocompromised patients, particularly human immunodeficiency virus (HIV)-positive patients, but CM may also occur in apparently immunocompetent individuals. Outcome analyses have been performed in such patients but, due to the high prevalence of HIV infection worldwide, CM patients today may be admitted to hospitals with unknown HIV status, particularly in underdeveloped countries. The objective of this multicenter study was to analyze all types of CM cases in an aggregate cohort to disclose unfavorable outcomes. We retrospectively reviewed the hospitalized CM patients from 2000 to 2015 in 26 medical centers from 11 countries. Demographics, clinical, microbiological, radiological, therapeutic data, and outcomes were included. Death, neurological sequelae, or relapse were unfavorable outcomes. Seventy (43.8%) out of 160 study cases were identified as unfavorable and 104 (65%) were HIV infected. On multivariate analysis, the higher Glasgow Coma Scale (GCS) scores (p?=?0.021), cerebrospinal fluid (CSF) leukocyte counts > 20 (p?=?0.038), and higher CSF glucose levels (p?=?0.048) were associated with favorable outcomes. On the other hand, malignancy (p?=?0.026) was associated with poor outcomes. Although all CM patients require prompt and rational fungal management, those with significant risks for poor outcomes need to be closely monitored.     

Left ventricular mechanical dispersion is associated with nonsustained ventricular tachycardia in hypertrophic cardiomyopathy

Objective: We assessed the value of speckle tracking two-dimensional (2D) strain echocardiography (2DSE) measured mechanical dispersion (MD) with other imaging and electrocardiographic parameters in differentiating hypertrophic cardiomyopathy (HCM) patients with and without nonsustained ventricular tachycardia (NSVT) on 24-h ambulatory ECG monitoring.

Methods and results: We studied 31 patients with HCM caused by the Finnish founder mutation MYBPC3-Q1061X and 20 control subjects with comprehensive 2DSE echocardiography and cardiac magnetic resonance imaging (CMRI). The presence of NSVT was assessed from ambulatory 24-h ECG monitoring.

NSVT episodes were recorded in 11 (35%) patients with HCM. MD was significantly higher in HCM patients with NSVT (93?±?41?ms) compared to HCM patients without NSVT (50?±?18?ms, p?=?0.012) and control subjects (41?±?16?ms, p?Conclusions: Increased mechanical dispersion was associated with NSVT in HCM patients on 24-h ambulatory ECG monitoring.

• Key messages

• The prediction of sudden cardiac death in hypertrophic cardiomyopathy remains a challenge and novel imaging methods are required to identify individuals at risk of malignant ventricular arrhythmias.

• Mechanical dispersion by speckle tracking echocardiography is associated with NSVT on 24-h ambulatory ECG monitoring in patients with hypertrophic cardiomyopathy

     

Triiodothyronine and Thyroxine in the Serum and Thyroid Glands of Iodine-Deficient Rats

Triiodothyronine (T(3)) and thyroxine (T(4)) were measured by immunoassay in the serum and thyroid hydrolysates of control (group A), mildly iodine-deficient (group B), and severely iodine-deficient rats (group C). These results were correlated with changes in thyroidal weight, (131)I uptake and (127)I content as well as with the distribution of (131)I in Pronase digests of the thyroid. There was a progressive increase in thyroid weight and (131)I uptake at 24 h with decrease in iodine intake. The (127)I content of the thyroids of the group B animals was 44% and that of the group C animals 2% of that in group A. The mean labeled monoiodotyrosine/diiodotyrosine (MIT/DIT) and T(3)/T(4) ratios in group A were 0.42+/-0.07 (SD) and 0.12+/-0.01, 0.59+/-0.06 and 0.11+/-0.03 in group B, and 2.0+/-0.3 and 1.8+/-0.9 in the group thyroid digests.Mean serum T(4) concentration in the control rats was 4.2+/-0.6 (SD) mug T(4)/100 ml, 4.5+/-0.3 mug/100 ml in group B animals, and undectectable (<0.5 mu(4)/100 ml) in group C animals. There was no effect of iodine deficiency on serum T(3) concentrations, which were 44+/-9 (Mean+/-SD) ng/100 ml in A animals, 48+/-6 ng/100 ml n B animals, and 43+/-6 ng/100 ml in the C group. Thyroidal digest T(3) and T(4) concentrations were 39 and 400 ng/mg in group A animals and were reduced to 5 and 1% of this, respectively, in group C. The molar ratio of T(3)/T(4) in the thyroid digests of the groups A and B animals was identical to the ratio of labeled T(3)/T(4) and was slightly less (1.0+/-0.9) than the labeled T(3)/T(4) ratio in the group C animals.The mean ratio of labeled T(4) to labeled T(3) in the serum of the severely iodine-deficient animals 24 h after isotope injection was 11+/-1 (SEM). With previously published values, it was possible to correlate the ratio of labeled T(4)/T(3) in the thyroid digest with the labeled T(4)/T(3) ratio in the serum of each iodine-deficient animal. This analysis suggested that the labeled thyroid hormones in the severely iodine-deficient rat were secreted in the ratio in which they are present in the gland.Kinetic analysis of total iodothyronine turnover indicated that two-thirds of the T(3) utilized per day by the iodine-sufficient rat arises from T(4). If the T(4)-T(3) conversion ratio remains the same in iodine deficiency, then the analysis suggests that about 90% of the T(3) arises directly from the thyroid. Therefore, it would appear that absolute T(3) secretion by the thyroid increases severalfold during iodine deficiency. The fact that serum T(3) remains constant and T(4) decreases to extremely low levels, combined with previous observations that iodine-deficient animals appear to be euthyroid, is compatible with the hypothesis that T(4) in the normal rat serves primarily as a precursor of T(3).     

A fusidic acid-resistant epidemic strain of Staphylococcus aureus carries the fusB determinant, whereas fusA mutations are prevalent in other resistant isolates

Fusidic acid-resistant epidemic Staphylococcus aureus strains causing impetigo bullosa have been reported in Scandinavia. We show that these strains form part of a European epidemic clonotype that carries the fusB determinant. In contrast, resistance to fusidic acid in a collection of nonepidemic strains resulted primarily from mutations in fusA.     

Engineering anthracycline biosynthesis toward angucyclines

The biosynthesis pathways of two anthracyclines, nogalamycin and aclacinomycin, were directed toward angucyclines by using an angucycline-specific cyclase, pgaF, isolated from a silent antibiotic biosynthesis gene cluster. Addition of pgaF to a gene cassette that harbored the early biosynthesis genes of nogalamycin resulted in the production of two known angucyclinone metabolites, rabelomycin and its precursor, UWM6. Substrate flexibility of pgaF was demonstrated by replacement of the nogalamycin minimal polyketide synthase genes in the gene cassette with the equivalent aclacinomycin genes together with aknE2 and aknF, which specify the unusual propionate starter unit in aclacinomycin biosynthesis. This modification led to the production of a novel angucyclinone, MM2002, in which the expected ethyl side chain was incorporated into the fourth ring.