TREATMENT OF SUPERFICIAL MYCOSES IN THE TROPICS: WHITFIELD'S OINTMENT VERSUS CLOTRIMAZOLE

Background. In tropical primary health care, essential drugs should be safe, effective, and as inexpensive as possible. To treat the very common dermatophyte infections of the skin, one may use inexpensive Whitfield's preparations, more expensive topical imidazole derivatives, or extremely expensive oral antifungals. Because a cream base is felt to be more appropriate than an ointment in tropical conditions, we wanted to compare the effectiveness of Whitfield's cream and a topical imidazole derivative in field conditions in the tropics. Methods. A double-blind trial was performed involving 153 patients with a dermatophyte infection of the skin in Karonga District, Northern Malawi, including 25 patients who were Hiv-i-seropositive, comparing Whitfieid's cream with clotrimazole cream. Results. 75 patients were treated with Whitfield's cream and 78 with clotrimazole cream for a period of 6 weeks. Cure rates ranged from 80% to over 90% depending on the definition of cure. If positive cultures after treatment were used as criterion for treatment failure, six were found in each treatment group. One in each treatment failure group was an mv-i-seropositive patient. Conclusions. The great majority of patients in the tropics with a dermatophyte infection of the skin can be cured with a topical antimycotic preparation and do not need expensive oral therapy. This also proved to be valid for HIV-I-seropositive patients. Whitfield's cream and clotrimazole cream are both very effective. The lower cost makes Whitfield's cream the treatment of choice in dermatophyte infections of the skin in tropical primary health care.     

Electrical Performance and Automatic Capture Characteristics of a 3.5-mm2 Passive Fixation Lead during 1-Year Follow-Up

Background: Bipolar low polarization electrodes are recommended for a regular AutoCapture™ (St. Jude Medical, Inc., Sylmar, CA, USA) function in order to effectively detect the evoked response (ER) signal. The objective of this national multicenter registry was to evaluate the electrical performance and the AutoCapture™ characteristics of the bipolar ventricular pacing lead IsoFlex S, model 1636T or 1646T (St. Jude Medical), in combination with single- and dual-chamber pacemakers.
Methods: Ventricular pacing and sensing thresholds, lead impedance, ER amplitude, and polarization signals were measured at discharge and routine follow-up visits after 1, 3, 6, 9, and 12 months. AutoCapture™ activation was recommended based on the results of the ER sensitivity test.
Results: Of the 252 patients initially included, 109 (43%) have completed the follow-up. The mean ventricular pacing threshold was 0.43 ± 0.19 V at discharge and 0.68 ± 0.32 V at 12 months postimplant. The values for the ventricular sensing threshold were between 9.51 ± 4.12 and 9.99 ± 4.09 mV at discharge and at the 12-month follow-up. The unipolar lead impedance decreased from 533 ± 94 to 476 ± 73 ohms during the follow-up. The mean ER amplitude was 16.47 ± 6.70 mV at discharge and 17.42 ± 7.43 mV after 12 months, and the corresponding mean polarization signals were 0.59 ± 1.00 and 0.74 ± 1.24 mV, respectively. AutoCapture™ activation was recommended in at least 95% of the patients investigated over the 12-month follow-up.
Conclusion: The bipolar ventricular pacing lead IsoFlex S 1636/1646T shows a good electrical performance and is mostly compatible with the AutoCapture™ algorithm.     

高三尖杉酯碱酰胺的结构测定

三尖杉树皮粗提取物中的一个新生物碱—高三尖杉酯碱酰胺(homoharringtonamide)的结构,经质谱—质谱分析,初步建议为16。类似的酰胺类生物碱,例如三尖杉碱酰胺(cephalotaxamide,6)、11-羟基三尖杉碱酰胺(11-hydroxycephalotaxamide,9)、三尖杉酯碱酰胺(harfingtonamide,14)或异三尖杉酯碱酰胺(isoharringtonamide,15)也可能存在,后三者(9,14,15)尚未见报道。     

Exonic MHC-DRB Polymorphisms and Intronic Simple Repeat Sequenees: Janus'Faces of DNA Sequence Evolution

The evolution of highly polymorphic gene loci is following routes that cannot be extrapolated from the existing knowledge of single copy genes. In addition, interpreting the evolution of the most polymorphic loci in vertebrates requires a plethora of data from different taxa. We evaluate here the rules for the evolution of Major Histocompatibility Complex (MHC-)DRB genes recently established in humans and other primates on the basis of sequences from several artiodactyl species. MHC genes encode essential molecules for self/altered-self/non-self discrimination in the interaction of the organism with its environment. The necessity to effectively present various different antigens to immunocompetent cells causes positive selection pressure on the variability of these genes in the population. Artiodactyls represent the third mammalian order in which this phenomenon was evidenced independently. A further incentive to investigate also the surroundings of MHC-DRB loci was the presence of a particular repetitive sequence stretch in the vicinity of the polymorphic exon - in addition to the evolutionarily old alleles, ancient polymorphisms and the mechanisms for their generation and/or maintenance. Besides their utility for indirect gene diagnosis (MHC-DRB typing), the closely linked stretches of simple repetitive DNA in the neighborhood of the highly polymorphic MHC-DRB genes are also interesting remains of the evolutionary history. Evolutionary developmenl is different in genetically inert intron-ic DNA compared to the exonic counterparts, despite their close vicinity. The persistence of these simple repeats over nearly 100 million years in one location preserving the same basic motif structure is startling. Indirect evidence is weighed that biological meaning should be considered for these elements. The combined analysis of the polymorphic DRB genes and the (highly variable but persistent) simple repeat stretches deepen our understanding of the complexities within a unique genomic compartment encoding essential molecules for self/non-self dif-ferentiation in the interaction of the organism with its environment.     

The thoracic aorta studied by MR imaging

Thirty-three patients with a variety of disorders of the thoracic aorta (aneurysm, dissection, Marfan syndrome, coarctation/pseudocoarctation, L-transposition, and Takayasu disease) were evaluated with magnetic resonance (MR) imaging. MR imaging delineated the presence and extent of thoracic aortic aneurysms and showed the relationship of the aneurysm to arch vessels; it also demonstrated intimal flaps and individual lumina in types A and B aortic dissection. Dilation of the ascending aorta in Marfan syndrome and focal narrowing of the aorta in coarctation were well visualized. The anteroposterior and side-to-side relationships of the aorta and pulmonary artery in L-transposition were demonstrated, as were aortic wall thickening and branch vessel narrowing in Takayasu arteritis. Initial experience suggests that MR imaging may provide a noninvasive method for evaluating thoracic aortic disease. Limitations include inferior spatial resolution, occasional difficulty in imaging the entire region of interest in one section, lack of signal from calcifications, and inability to monitor critically ill patients.