New indices for quantification of the power spectrum of heart rate variability time series without the need of any frequency band definition

This paper presents a new family of indices for the frequency domain analysis of heart rate variability time series that do not need any frequency band definition. After proper detrending of the time series, a cumulated power spectrum is obtained and frequencies that contain a certain percentage of the power below them are identified, so median frequency, bandwidth and a measure of the power spectrum asymmetry are proposed to complement or improve the classical spectral indices as the ratio of the powers of LF and HF bands (LF/HF). In normal conditions the median frequency provides similar information as the classical indices, while the bandwidth and asymmetry can be complementary measures of the physiological state of the tested subject. The proposed indices seem to be a good choice for tracking changes in the power spectrum in exercise stress, and they can guide in the determination of frequency band limits in other animal species.

Monitoring hand flexor fatigue in a 24-h motorcycle endurance race

Motorcycle riders must endure high levels of muscle tension for long periods of time, especially in their arms and forearms, when steering and using handlebar controls. Because the right hand operates the gas handle and front brakes, the present research focuses on fatigue in the right hand flexors. Ten adult riders, aged 32.5±5.5years, volunteered to participate in this study. During the 24h race each rider, on completion of a relay stage, visited the assessment box to do the following handgrip test sequence: (1) 10s of EMG recording at rest, (2) one 3-s maximal voluntary contraction (MVC), (3) 1min rest interval and (4) 50% MVC maintained during 10s. EMG amplitude (MP: μV) and median and mean frequency (MF and MPF: Hz) over the superficial finger flexors were recorded during the whole handgrip test sequence with adhesive surface electrodes. MVC values were maintained during the first two relays (50-60min duration in total) and dropped gradually thereafter (p<0.01). During the monitoring of the 50% MVC, mean amplitude increased (p=0.024) while median and mean frequency tended to decrease. These results suggest fatigue is produced in motorcycle riders in a 24h race. However, the expected reduction of EMG frequency was not confirmed given to a potentially large variability.

The application of a PCR technique for the detection of immunoglobulin heavy chain gene rearrangements in fresh or paraffin-embedded skin tissue

Although detection of a clonal sequence of the heavy chain gene of immunoglobulin by the polymerase chain reaction (PCR) is frequently used to assess lymphoid infiltrates in skin biopsy specimens, there are no data on the sensitivity and specificity of this test in detecting clonal B cell populations. Having refined a PCR technique for the detection of immunoglobulin heavy chain (IgH) gene rearrangement in both fresh and formalin-fixed, paraffin-embedded skin samples, we undertook to define the role of this assay in the diagnostic setting. Thirty-one cases of cutaneous B cell lymphoma (CBCL), 19 cases of B cell pseudolymphoma (lymphocytoma cutis), 34 cases of benign lymphocytic infiltrates of the skin and one case of cutaneous T cell lymphoma (CTCL) were studied using the polymerase chain reaction assay. All biopsies were formalin-fixed, paraffin-embedded skin sections apart from 13 of the 31 CBCL specimens which were fresh skin specimens. DNA from the framework region 3 (FR3) sequence of the IgH genes was amplified to ascertain the presence of a clonal IgH gene rearrangement. The findings were correlated with histological and immunophenotyping results on all samples. The assay performed with 73% sensitivity and 100% specificity, comparable to results obtained examining fresh lymphoid tissue specimens from patients with B cell tumours. The results indicate that this technique is a useful tool in the work up of suspected CBCL and in differentiating between CBCL and mixed lymphocytic infiltrates, a clearly important distinction with regards to prognosis and treatment.

PCB congeners transferred by human milk, with an estimate of their daily intake

The degree of exposure by nursing mothers to individual polychronated biphenyl (PCB) congeners was studied and an estimate made of the daily intake by their infants. Epidemiological data from 100 nursing mothers were collected; 11 individual PCB congeners were determined in samples of the mothers' milk and the toxicity equivalent (TEQ) calculated. The mothers' data and the congener levels were statistically correlated. In over 80% of the samples, PCB congeners nos 180, 28, 138 and 170 were identified, and in over 70%, PCB congeners nos 188, 52, 187 and 153. PCB congeners nos 183, 101 and 118 were identified in percentages of between 39 and 15% of the samples. The highest levels detected were those in PCB no. 28 (1.626 ppb), and the lowest concentrations corresponded to PCB no. 183 (0.109 ppb). The toxicity equivalent (TEQ) was calculated from the toxic equivalent factor (TEF) of the congeners studied. There were no statistical differences between the geographical place of residence, age, occupation, and the congeners studied. There was a significant differentiation with respect to the birthplace, the location of industrial estates and the irrigation facilities in the area of residence, to smoking, the consumption of a varied diet, meat, fish or industrially processed foods, the physical constitution of the mothers, number of children and lactation periods, and PCB congener levels. The total PCB daily intake estimate was under the acceptable daily intake (ADI) limits of tolerance (WHO, 1988), and it was not possible to come to any conclusions for the estimated daily intake (EDI) of the 11 congeners studied since these have not yet been established. It was thus proposed to use the EDIs obtained in order to establish the ADIs of the individual PCB congeners.

Measurement of Candida-specific blastogenesis: comparison of carboxyfluorescein succinimidyl ester labelling of T cells, thymidine incorporation, and CD69 expression

Measurement of the T cell blastogenic response to Candida may be useful in the evaluation of patients with suspected immunodeficiency. The classic blastogenesis assay is based on uptake of [3H]thymidine by peripheral blood lymphocytes stimulated with Candida antigens for 5 days. An alternative approach involves staining peripheral blood lymphocytes with the intracellular fluorescent dye carboxyfluorescein succinimidyl ester (CFSE) and measuring mitotic activity by the successive twofold reductions in fluorescent intensity using flow cytometry (FCM). The two approaches were compared in 16 subjects who demonstrated various proliferative responses to Candida. FCM-derived indices all involved initial gating on CD3+ T cells and included 1) blastic transformation as measured by changes in light scatter, 2) cell division, measured by CFSE fluorescence, and 3) CD69 expression. A good correlation was found between [3H]thymidine uptake and CFSE-derived indices, irrespective of the analysis algorithm used to interpret CFSE division profiles. Furthermore, significant T cell proliferation occurred only in subjects who had had one or more symptomatic episodes of vaginal candidiasis whereas controls with no such history, and patients with chronic vaginal infection, showed minimal proliferation. The increase in proportion of CD69+ T cells in culture also correlated with the blastogenic response to Candida, but less well than mitotic indices. CFSE-derived indices of T cell blastogenesis to Candida are equivalent to [3H]thymidine-based assays and may allow useful laboratory distinction between subjects who have been exposed to and recovered from vaginal Candida infection, who have a strong proliferative response, from those with no exposure or chronic infection who demonstrate a poor response.

Organochlorine pesticides in pasteurized milk and associated health risks

The presence of organochlorine pesticides (alpha-HCH, beta-HCH, lindane, aldrin, dieldrin, heptachlor, heptachlor epoxide, chlordane and the isomers and metabolites of DDT) in Spanish pasteurized milk were investigated. 95% of the samples contained one of the isomers of the HCH group and 12.9% of them exceeded the maximum residue limit permitted by the European Union; six samples went over that limit for heptachlor epoxide and 74.63% of the samples contained chlordane at higher concentrations than those permitted by the legislation. None of the samples exceeded the limit for the DDT group. The mean concentrations detected for each pesticide were as follows (mg/kg): alpha-HCH = 0.015; beta-HCH = 0.039; lindane = 0.007; delta-HCH = 0.07; aldrin = 0.002; dieldrin = 0.028; chlordane = 0.101; heptachlor = 0.011; heptachlor epoxide = 0.021; o.p'-DDD = 0.016; p.p'-DDD = 0.009; p.p'-DDE = 0.045 (DDT + metabolites = 0.067).

Aflatoxin-producing strains of Aspergillus flavus in the mould flora of the different greenhouse substrates for the cultivation of cucumber (Cucumis sativus, L.)

Fungal contamination in a greenhouse for production of cucumbers (Cucumis sativus, L.) was studied. 158 samples of water, sand, air, leaves and fruits were analyzed. 25 different genera were isolated, the most frequent ones being Pullularia, Aspergillus, Paecilomyces, Alternaria, Fusarium, Rhizopus and Penicillium. Pullularia, Aspergillus, Paecilomyces and Penicillium were present in all types of samples studied. Twenty-one strains of A. flavus were identified and only eight of those produced aflatoxins "in vitro".

Sporotrichosis in the Orinoco river basin of Venezuela and Colombia

Six cases of sporotrichosis from the Orinoco river basin of Venezuela and Colombia are described; two are of the localized cutaneous type and four are lymphocutaneous. Diagnosis was based on the patient's clinical history and mycological culture. Epidemiology and distinctive cultural habits of the patients are discussed in connection with disease etiology.

Bilateral seminoma 34 years after orchiopexy

A case of bilateral seminoma in a 59-year-old patient who had undergone bilateral orchiopexy 34 years previously is presented. To our knowledge this is the longest interval between an orchiopexy and diagnosis of bilateral malignancy.