Prevalence of primary HIV-1 drug resistance in pregnant women and in newly diagnosed adults at Tijuana General Hospital, Baja California, Mexico

At Tijuana General Hospital, between March 2003 and June 2005, pregnant women and other adults, recently identified as HIV infected, antiretroviral naïve, were enrolled to examine the prevalence of primary HIV drug resistance. All subjects had the Calypte® HIV-1 BED Incidence enzyme immunoassay test to identify recent infection. Genotypic analysis of HIV-1 protease and reverse transcriptase regions in plasma was performed. Forty-six subjects participated, eight (17%) men, 38 (83%) women. Ten (22%) subjects were classified as having recent HIV infection. HIV genotype was performed in 41 subjects. One subject (2.5%) had a major mutation in the reverse transcriptase region (K219Q) conferring zidovudine resistance, one had a minor mutation at V118I (2.5%) and two subjects (5%) had minor mutation (V179D) associated with non-nucleoside reverse transcriptase inhibitor resistance. There were no major protease inhibitor-associated mutations but minor mutations were common. The prevalence of primary HIV drug resistance in Baja California is low.

Assessing crop N status of fertigated vegetable crops using plant and soil monitoring techniques

Evaluation of crop N status will assist optimal N management of intensive vegetable production. Simple procedures for monitoring crop N status such as petiole sap [NO ₃^--N], leaf N content and soil solution [NO ₃^-] were evaluated with indeterminate tomato and muskmelon. Their sensitivity to assess crop N status throughout each crop was evaluated using linear regression analysis against nitrogen nutrition index (NNI) and crop N content. NNI is the ratio between the actual and the critical crop N contents (critical N content is the minimum N content necessary to achieve maximum growth), and is an established indicator of crop N status. Nutrient solutions with four different N concentrations (treatments N1-N4) were applied throughout each crop. Average applied N concentrations were 1, 5, 13 and 22 mmol L^-1 in tomato, and 2, 7, 13 and 21 mmol L^-1 in muskmelon. Respective rates of N were 23, 147, 421 and 672 kg N ha^-1 in tomato, and 28, 124, 245 and 380 kg N ha^-1 in muskmelon. For each N treatment in each crop, petiole sap [NO ₃^--N] was relatively constant throughout the crop. During both crops, there were very significant (P < 0.001) linear relationships between both petiole sap [NO ₃^--N] and leaf N content with NNI and with crop N content. In indeterminate tomato, petiole sap [NO ₃^--N] was very strongly linearly related to NNI (R² = 0.88-0.95, P < 0.001) with very similar slope and intercept values on all dates. Very similar relationships were obtained from published data of processing tomato. A single linear regression (R² = 0.77, P < 0.001) described the relationship between sap [NO ₃^--N] and NNI for both indeterminate and processing tomato, each grown under very different conditions. A single sap [NO ₃^--N] sufficiency value of 1050 mg N L^-1 was subsequently derived for optimal crop N nutrition (at NNI = 1) of tomato grown under different conditions. In muskmelon, petiole sap [NO ₃^--N] was strongly linearly related to NNI (R² = 0.75 - 0.88, P < 0.001) with very similar slope and intercept values for much of the crop (44-72 DAT, days after transplanting). A single linear relationship between sap [NO ₃^--N] and NNI (R² = 0.77, P < 0.001) was derived for this period, but sap sufficiency values could not be derived for muskmelon as NNI values were >1. Relationships between petiole sap [NO ₃^--N] with crop N content, and leaf N content with both NNI and crop N content had variable slopes and intercept values during the indeterminate tomato and the muskmelon crops. Soil solution [NO ₃^-] in the root zone was not a sensitive indicator of crop N status. Of the three systems examined for monitoring crop/soil N status, petiole sap [NO ₃^--N] is suggested to be the most useful because of its sensitivity to crop N status and because it can be rapidly analysed on the farm.

Impact of chemotherapy on telomere length in sporadic and familial breast cancer patients

Recently, we observed that telomeres of BRCA1/2 mutation carriers were shorter than those of controls or sporadic breast cancer patients, suggesting that mutations in these genes might be responsible for this event. Given the contradictory results reported in the literature, we tested whether other parameters, such as chemotherapy, could be modifying telomere length (TL). We performed a cross-sectional study measuring leukocyte TL of 266 sporadic breasts cancer patients treated with first-line chemotherapy, with a median follow-up of 240 days. Additionally, we performed both cross-sectional and longitudinal studies in a series of 236 familial breast cancer patients that included affected and non-affected BRCA1/2 mutation carriers. We have measured in leukocytes from peripheral blood: the TL, percentage of short telomeres (<3 kb), telomerase activity levels and the annual telomere shortening speed. In sporadic cases we found that chemotherapy exerts a transient telomere shortening effect (around 2 years) that varies depending on the drug combination. In familial cases, only patients receiving treatment were associated with telomere shortening but they recovered normal TL after a period of 2 years. Chemotherapy affects TL and should be considered in the studies that correlate TL with disease susceptibility.

Epigenomic profiling in polycythaemia vera and essential thrombocythaemia shows low levels of aberrant DNA methylation

AIMS

The purpose of this study was to compare the DNA-methylation signature in classic chronic Philadelphia negative myeloproliferative neoplasms (MPN), polycythaemia vera (PV) and essential thrombocythaemia (ET), in order to obtain a global insight into DNA-methylation changes associated with these malignancies.

METHODS

Thirty-five MPN samples from 11 ET JAK2 V617F, 12 ET JAK2 wild type (WT) and 12 PV JAK2 V617F patients as well as 12 from healthy donors were analysed. DNA samples extracted from whole peripheral blood were hybridised to the 'HumanMethylation27 DNA Analysis BeadChip.'

RESULTS

All groups showed a very homogeneous methylation pattern. Only the ZNF577 gene showed a differential methylation profile between PV JAK2 V617F positive and controls. This aberrant methylation was correlated with a differential gene expression of ZNF577. No aberrant hypermethylation was found in the SOCS-1 and SOCS-3 genes.

CONCLUSIONS

According to our results, an aberrant methylation pattern does not seem to play a crucial role in MPN pathogenesis; nor does it justify phenotypical differences between PV and ET.

[Lemierre's syndrome]

Lemierre's syndrome is a rare disease, mostly affecting young adults in good health, which can lead to significant morbidity and mortality. We report one case with favourable outcome and clinical features stereotypics: angina, septic thrombosis of the internal jugular vein, pulmonary septic metastasis, Fusobacterium necrophorum on blood cultures. Antibiotic therapy targeting anaerobes has been rapidly initiated and maintained 4-6 weeks. The anticoagulation has been maintained 4 weeks.

Psychological variables and reality judgment in virtual environments: the roles of absorption and dissociation

Literature on virtual reality (VR) and psychology has focused on the influence that some basic psychological processes have on VR. Although psychological processes may be defined as common to all humans, there are individual differences that might make it difficult to provide the same VR experience for everyone. Of the several personality and psychological variables that might be relevant to the VR field, this study focuses on two: absorption and dissociation. Both psychological dimensions are deeply interrelated and might play an important role in the immersion of subjects in virtual environments and in the reality attributions they make. Thus, the purpose of this study was to ascertain personality correlates on differences regarding the VR experience. The subjects were 39 psychology undergraduate students who were immersed in a VR environment for 15 minutes. Our data suggest that both absorption and dissociation influenced central issues regarding reality judgment in VR.

International study on the psychometric attributes of the non-motor symptoms scale in Parkinson disease

BACKGROUND

Nonmotor symptoms (NMS) have a great impact on patients with Parkinson disease (PD). The Non-Motor Symptoms Scale (NMSS) is an instrument specifically designed for the comprehensive assessment of NMS in patients with PD. NMSS psychometric properties have been tested in this study.

METHODS

Data were collected in 12 centers across 10 countries in America, Asia, and Europe. In addition to the NMSS, the following measures were applied: Scales for Outcomes in Parkinson's Disease (SCOPA)-Motor, SCOPA-Psychiatric Complications (SCOPA-PC), SCOPA-Cognition, Hoehn and Yahr Staging (HY), Clinical Impression of Severity Index for Parkinson's Disease (CISI-PD), SCOPA-Autonomic, Parkinson's Disease Sleep Scale (PDSS), Parkinson's Disease Questionnaire-39 items (PDQ-39), and EuroQol-5 dimensions (EQ-5D). NMSS acceptability, reliability, validity, and precision were analyzed.

RESULTS

Four hundred eleven patients with PD, 61.3% men, were recruited. The mean age was 64.5 +/- 9.9 years, and mean disease duration was 8.1 +/- 5.7 years. The NMSS score was 57.1 +/- 44.0 points. The scale was free of floor or ceiling effects. For domains, the Cronbach alpha coefficient ranged from 0.44 to 0.85. The intraclass correlation coefficient (0.90 for the total score, 0.67-0.91 for domains) and Lin concordance coefficient (0.88) suggested satisfactory reproducibility. The NMSS total score correlated significantly with SCOPA-Autonomic, PDQ-39, and EQ-5D (r(S) = 0.57-0.70). Association was close between NMSS domains and the corresponding SCOPA-Autonomic domains (r(S) = 0.51-0.65) and also with scales measuring related constructs (PDSS, SCOPA-PC) (all p < 0.0001). The NMSS total score was higher for women (p < 0.02) and for increasing disease duration, HY, and CISI-PD severity level (p < 0.001). The SEM was 13.91 for total score and 1.71 to 4.73 for domains.

CONCLUSION

The Non-Motor Symptoms Scale is an acceptable, reproducible, valid, and precise assessment instrument for nonmotor symptoms in Parkinson disease.

SNCA multiplication is not a common cause of Parkinson disease or dementia with Lewy bodies

The authors recently have shown that triplication of the alpha-synuclein gene (SNCA) can cause Parkinson disease (PD) and diffuse Lewy body disease within the same kindred. The authors assessed 101 familial PD probands, 325 sporadic PD cases, 65 patients with dementia with Lewy bodies, and 366 neurologically normal control subjects for SNCA multiplication. The authors did not identify any subjects with multiplication of SNCA and conclude this mutation is a rare cause of disease.

[Purulent meningitis and bacteremia from Bacteroides fragilis revealing a meningioma]

We report the case of a 78-year-old-woman with a meningitis caused by Bacteroides fragilis revealing a malignant tumor. The epidemiologic, etiologic and therapeutic features of these meningitis are reviewed.

Location of Pinacyanol in Micellar Solutions of N-Alkyl Trimethylammonium Bromide Surfactants

The interaction of pinacyanol (PIN), a cationic dye formed by monomer and dimer species, with three cationic surfactants (DTAB, TTAB, and HTAB) has been studied spectroscopically and by acid-base equilibrium in the micellar concentration range. In the presence of surfactants, the absorption maximum of the two main peaks undergoes bathochromic shifts. The spectral shifts suggest a hydrophobic environment of the chromophore. The presence of micelles favors the monomer species; i.e., it reduces the extent of dimerization. The pK(a) of PIN in micellar medium is similar to the value in pure water. When acid-base equilibrium was considered, the changes in the interfacial pK(a) allowed to us to determine the constant dielectric for the interfacial region (epsilon=69). This led to the conclusion that the dye must be solubilized between the solution and the hydrocarbon chain core, i.e., in the aqueous micellar interface. This location can be explained by a cation-pi interaction between the uncharged ring system of the dye and the cationic headgroups of the surfactants. Copyright 2001 Academic Press.

A new hyperrecombination mutation identifies a novel yeast gene, THP1, connecting transcription elongation with mitotic recombination

Given the importance of the incidence of recombination in genomic instability, it is of great interest to know the elements or processes controlling recombination in mitosis. One such process is transcription, which has been shown to induce recombination in bacteria, yeast, and mammals. To further investigate the genetic control of the incidence of recombination and genetic instability and, in particular, its connection with transcription, we have undertaken a search for hyperrecombination mutants among a large number of strains deleted in genes of unknown function. We have identified a new gene, THP1 (YOL072w), whose deletion mutation strongly stimulates recombination between repeats. In addition, thp1 Delta impairs transcription, a defect that is particularly strong at the level of elongation through particular DNA sequences such as lacZ. The hyperrecombination phenotype of thp1 Delta cells is fully dependent on transcription elongation of the repeat construct. When transcription is impeded either by shutting off the promoter or by using a premature transcription terminator, hyperrecombination between repeats is abolished, providing new evidence that transcription-elongation impairment may be a source of recombinogenic substrates in mitosis. We show that Thp1p and two other proteins previously shown to control transcription-associated recombination, Hpr1p and Tho2p, act in the same "pathway" connecting transcription elongation with the incidence of mitotic recombination.

Electrophoretic properties of dodecyltrimethylammonium bromide micelles in KBr solution

Charge in ionic micelles determines the trends of their stability and their practical applications. Charge can be calculated from zeta potential (zeta) measurements, which, in turn, can be obtained by Doppler microelectrophoresis. In this study, the electrophoretic properties of dodecyltrimethylammonium bromide (DTAB) in KBr aqueous solution (0-6 mM) were determined by Doppler microelectrophoresis. At very low surfactant concentrations (up to 6 mM), zeta potential was quite constant and due to the ionized monomers (DTA+). Above 6 mM, zeta potential increased to a maximum at surfactant concentrations still below the critical micellar concentration (CMC). This increase could be explained by a formation of nonmicellar aggregates of DTAB. Then, above the CMC, zeta potential underwent an abrupt reduction, which was dependent qualitatively and quantitatively on KBr concentration, and which could be due to an increase of the number of counterions adsorbed on the micelle surface. Calculation of effective micellar charge from zeta potential gave the surface charge density. Comparing this value with the theoretical, obtained from geometrical considerations, a fraction of 0.29 of charged micellar headgroups was obtained when DTAB was in aqueous solution, which is consistent with the value obtained by conductivity measurements.

Involvement of calcium in ACC-oxidase activity from Cicer arietinum seed embryonic axes

Both in vivo and in vitro ACC-oxidase activities as well as ethylene production from embryonic axes of chickpea seeds were strongly inhibited by EGTA, a selective extracellular Ca2+ ion chelator, indicating that the influx of Ca2+ is important for enzymatic activity. EGTA inhibition was restored by exogenous Ca2+. Treatments of embryonic axes with either Verapamil and LaCl3 (both Ca2+ channel blockers) or TMB-8 (an intracellular Ca2+ antagonist) provoked an inhibition of both ACC-oxidase activity and ethylene production. These results suggest an involvement of calcium fluxes and intracellular calcium levels in the activity of the last step of the ethylene biosynthetic pathway, which is, in turn, intimately correlated with germination of Cicer arietinum seeds.

Influence of Size on Electrokinetic Behavior of Phosphatidylserine and Phosphatidylethanolamine Lipid Vesicles

The aim of this study was to examine the electrokinetic properties of liposomes containing either phosphatidylethanolamine (PE) or phosphatidylserine (PS). Zeta potential was determined by laser-Doppler microelectrophoresis. The presence of PE enhanced the slight negative charge on the phosphate group of phosphatidylcholine. A linear relation between zeta potential and PE concentration was found. Absolute values of zeta potential were higher in PS liposomes and showed an exponential dependence on the PS content. The electrophoretic mobility depended not only on the percentage of aminophospholipid but also on the size of vesicles. This behavior can be explained by the relaxation effect. From geometrical considerations, it was possible to calculate the theoretical surface charge densities. Comparing experimental with theoretical values, an underestimation of zeta potential was found by the electrokinetic classic theory in the experimental conditions used. Copyright 1998 Academic Press.

Determination of polyethylene glycol activated with cyanuric chloride in liposomes

A simple method was developed for the determination of polyethylene glycol (PEG) 5000 activated with cyanuric chloride attached or adsorbed to the liposome membrane. The procedure is based in the measurement of the absorbance at 234 nm of the triazine ring of cyanuric chloride after disrupting the liposomal structure with CHCl3/MeOH (1/8, v/v). In this medium, the molar absorptivity of the molecule is the highest, and lipid does not interfere with the measurement. This procedure results in a convenient, sensitive, and rapid method for the determination of this kind of activated polyethylene glycol in liposomes. The minimal concentration of PEG measured is 50 microM, and so the method is sufficiently sensitive to quantify PEG 5000 in the minimal amounts used for protecting the liposomes from the action of serum. Values calculated by this method have been compared with those obtained by 1H NMR, and a good correlation between them has been obtained.

Bilayer distribution of phosphatidylserine and phosphatidylethanolamine in lipid vesicles

The distribution of phosphatidylethanolamine (PE) and phosphatydilserine (PS) in liposomes was studied as a function of aminophospholipid concentration using fluorescamine as labeling reagent. The method is suitable for such determination since, in the assay conditions, fluorescamine does not penetrate the vesicles nor does it disrupt them. The liposomes were obtained by sonication, extrusion, or mechanical dispersion (MLV). For any kind of vesicle, the percentage of PS in the external monolayer is higher than that obtained for PE in the corresponding vesicles. In extruded PS liposomes, this aminophospholipid is located preferentially in the outer layer, while for PE liposomes the localization depends on the size of vesicle. Sonicated liposomes present an asymmetrical distribution of both aminophospholipids, and the external location of PS or PE always predominates. In contrast, in MLV, aminophospholipids are mainly found in the inner layers of the vesicles, except for liposomes formed by the lowest PS proportion. A remarkable feature of PS liposomes is the reduction of vesicle size, especially in MLV liposomes, in comparison with neutral liposomes.

Physicochemical properties of enrofloxacin

The physicochemical properties of enrofloxacin, a fluoroquinolone that inhibits the activity of bacterial DNA gyrase, are described. Its spectral, solubility and related physicochemical characteristics are discussed. The dissociation behaviour of enrofloxacin was examined by UV spectrophotometry at 25 degrees C in a series of buffers ranging from pH 1 to 10. The corresponding macro- and microscopic dissociation constants were calculated. The apparent n-octanol-water partition coefficients were measured from pH 2 to 10.

Inhibition of xylazine induced uterine contractility by clenbuterol and nifedipine

A study was undertaken in order to determine the effects of xylazine on uterine contractility in goats premedicated with clenbuterol or nifedipine. These drugs inhibit uterine activity by acting as potent tocolytic or uterine relaxant agents. A balloon-tipped catheter was inserted under sedation and local anaesthesia on to a uterine horn in 15 cycling goats in order to record intrauterine pressure changes. Three groups of five goats were used: group I was treated with an intravenous dose of 0.1 mg kg-1 of xylazine. Groups II and III were pretreated with 4 micrograms kg-1 of clenbuterol and 80 micrograms kg-1 of nifedipine, respectively, before administrating the same dose of zylazine. Xylazine increased the frequency and intensity of uterine contractions significantly and the value of the area under the contraction curves was significantly higher than that observed under basal conditions i.e. before drug treatment. In goats premedicated with clenbuterol or nifedipine, the uterotonic effects of xylazine (2858 +/- 217 versus basal contractility: 1241 +/- 173 mm2.5 min-1, P < 0.05) were inhibited for the 30 minutes recording period. These data indicate that clenbuterol and nifedipine can be used as potent tocolytic agents in order to prevent the uterine side effects of xylazine.

Regulation of the ASC system and Na+/K + pump activities in brown trout (Salmo trutta) hepatocytes

The present study investigates the regulation of Na+/K+ pump activity and alanine uptake in trout hepatocytes. Pump activity increased when cells were incubated in an amino-acid-free medium, while it was reduced in cells from fasted animals. Short-term exposure (3 h) to glucagon modified the activity of the pump in a complex seasonally dependent pattern: in experiments carried out in autumn and winter there was some inhibition, while in spring the pump was activated by this hormone. Pharmacological modification of levels of two intracellular signal transducers, namely cyclic AMP and Ca2+, always led to a reduction in pump activity. These experiments were conducted in May, when activation of the pump by glucagon exposure occurred. There is no apparent explanation for the mechanism by which this hormone modifies the activity of the pump. Glucagon also regulates the activity of system ASC (a Na+-dependent amino acid carrier with short-chain neutral amino acids as preferred substrates). This regulation also showed a seasonally dependent pattern, although the pattern was opposite to that found for the regulation of Na+/K+ pump activity.

[Lithium poisoning]

A case of therapeutic overdosage in a 58-year-old woman is reported. Lithium plasma level was 3.7 mmol.l. All clinical and biological disturbances regressed in 3 days after controlled rehydration only. Aetiology, clinical picture, biological characteristics and treatment according to the severity of the lithium poisoning are discussed.

Angina pectoris following cisplatin, etoposide, and bleomycin in a patient with advanced testicular cancer

OBJECTIVE

To report a case of angina pectoris associated with chemotherapy for testicular cancer.

CASE SUMMARY

An HIV-infected patient with massive retroperitoneal metastases of a mixed embryonal and undifferentiated teratocarcinoma was treated with cisplatin, etoposide, and bleomycin. While the patient was receiving the second course of chemotherapy, he developed several episodes of angina pectoris that responded to nitroglycerin. Coronary angiography excluded structural abnormalities in the coronary arteries. The patient was treated prophylactically with nifedipine during the 2 following courses of chemotherapy with no new ischemic events.

DISCUSSION

Coronary vasospasm seemed to be responsible for the angina in this patient. Several pathogenetic mechanisms that could explain these vascular events are discussed, including the possible role of bulky metastatic disease.

CONCLUSIONS

The combination of cisplatin, etoposide, and bleomycin for testicular cancer, perhaps associated with bulky metastatic disease, can induce vasospastic phenomena that might be life-threatening.

Design and applications of a new fluorimetric assay of thioguanine in liposomes

This paper describes the systematic design of a modification that overcomes the difficulties encountered with the original fluorimetric method for thioguanine. It allows the determination of thioguanine alone, as well as in a lipid medium (specifically in liposomes). It consists of an earlier lipid extraction based on liquid-solid extraction cartridges; then the oxidation of thioguanine in the lipid-free solution is performed by adding hydrogen peroxide in pH 4.7 acetate buffer at 50 degrees C for 30 min. A central composite design was used to finally optimize the method. The assay is precise (RSD values were 1.8 and 2.1% for intra-day and between-day precision, respectively). The detection limit was 0.05 microM and the limit of quantitation 0.08 microM.

Ethylene Production and 1-Aminocyclopropane-1-Carboxylic Acid Conjugation in Thermoinhibited Cicer arietinum L. Seeds

The effect of supraoptimal temperatures (30 degrees C, 35 degrees C) on germination and ethylene production of Cicer arietinum (chick-pea) seeds was measured. Compared with a 25 degrees C control, these temperatures inhibited both germination and ethylene production. The effect of supraoptimal temperatures could be alleviated by treating the seeds with ethylene. It was concluded that one effect of high temperature on germination was due to its negative effect on ethylene production. This inhibitory effect of high temperature was due to increased conjugation of 1-aminocyclopropane-1-carboxylic acid to 1-(malonylamino)cyclopropane-1-carboxylic acid and to an inhibition of ethylene-forming enzyme activity.

Quantitative determinations of chemical compounds with nutritional value from Inca crops: Chenopodium quinoa ('quinoa')

Quantitative determinations of total and soluble proteins, total and free sugars, starch, total lipids, tanins, ash (Ca, Na, K, Fe, and P), and caloric value were carried out on quinoa flour. Results show that the amount of soluble proteins was higher than the standard value for wheat and maize and was very close to that of barley's. The yield of free sugars like glucose (4.55%), fructose (2.41%) and sucrose (2.39%) were also of importance. Iron and calcium levels were higher than the reported values for maize and barley. The same occurred for the caloric value (435.5 Kcal/100 g). The content of saponins was also examined since its effect on red blood cells of group A and O has been related as a potential problem of the Andes population. From the chemical analysis a more complete view about quinoa as human food was presented.

New spectroscopic results in Kr VIII

New Kr VIII spectroscopic results between 280 and 2000 A using a theta-pinch and a discharge tube are presented, including one new energy level and two new classified lines. The previous analysis was also revised, and the uncertainty in the resulting level values is now <10 cm(-1).

Light source for obtaining spectra of highly ionized gases

Characteristics of a simple and compact spectral light source for obtaining the spectra of highly ionized gases are presented. Krypton and xenon spectrograms have been produced which show spectral lines belonging to a high degree of ionization.