A simple stochastic model of spatially complex neurons

A method for studying the coding properties of a multicompartmental integrate-and-fire neuron of arbitrary geometry is presented. Depolarization at each compartment evolves like a leaky integrator with an after-firing reset imposed only at the trigger zone. The frequency of firing at the steady-state regime is related to the properties of the multidimensional input. The decreasing variability of subthreshold depolarization from the dendritic tree to the trigger zone is shown for an input that is corrupted by a white noise. The role of a Poissonian noise is also investigated. The proposed method gives an estimate of the mean interspike interval that can be used to study the input output transfer function of the system. Both types of the stochastic inputs result in broadening the transfer function with respect to the deterministic case.

Effects of acute alcohol intoxication on pituitary-gonadal axis hormones, pituitary-adrenal axis hormones, beta-endorphin and prolactin in human adolescents of both sexes

Teenage drinking continues to be a major problem in industrialized countries, where almost 35% of alcohol drinkers are under 16 years old. In the present paper we studied the effects of acute alcohol intoxication (AAI) on the pituitary-gonadal (PG) axis hormones, and the possible contribution of pituitary-adrenal (PA) axis hormones, beta-endorphin (BEND), and prolactin (PRL) to the alcohol-induced dysfunction of PG axis hormones. Blood samples were drawn from adolescents that arrived at the emergency department with evident behavioral symptoms of drunkenness (AAI) or with nil consumption of alcohol (controls [C]). Our results demonstrated that AAI produces in adolescents a high increase in plasma PRL, ACTH, and cortisol (F), and a contradictory behavior of testosterone (T) according to gender: plasma T was increased in females and decreased in males. ACTH and PRL correlated positively with F, dehydroepiandrosterone-sulphate (DHEAS) and T in females, which suggests that PRL and ACTH could synergistically stimulate adrenal androgen production. In contrast, the decrease in T and increase in BEND in males suggests that AAI could have an inhibitory effect on testicular T, perhaps mediated by BEND. The hormones studied are involved in the development of secondary sexual characteristics and the growth axis during adolescence. The deleterious effects of alcohol abuse should be made known to adolescents and the appropriate authorities.

The developmental transition to flowering represses ascorbate peroxidase activity and induces enzymatic lipid peroxidation in leaf tissue in Arabidopsis thaliana

Leaf senescence in many plant species is associated with increased oxidative damage to cellular macromolecules by reactive oxygen species (ROS). Since ROS levels and their damage products in many plants are known to increase during senescence, it is possible that these changes are due to a decline in the levels of certain antioxidant enzymes. Using specific assays, we find that the developmental transition to bolting and flowering is associated with up to a 5-fold decline in ascorbate peroxidase activity and an increase in chloroplastid superoxide dismutase. As expected, these changes are associated with a measured increase in lipid peroxidation products. By HPLC separation of the products, we identified the different positional isomers and find that stereospecific lipid peroxidation occurs after the bolting transition. The product distribution suggests that enzyme-mediated lipid peroxidation, via a lipoxygenase, is responsible for the observed increase. Surprisingly, though consistent with the known induction of antioxidant defenses by hydrogen peroxide, the activity of APX rebounds with further development (reproduction and seed setting) and this increase (up to 5-fold) is associated with declines in lipid peroxidation and with the onset of visible senescence symptoms. Thus, in Arabidopsis, ROS increases are associated with the developmental transition to flowering, perhaps due to programmed declines in APX activity, and apparently lead to the oxidative activation of lipoxygenase and subsequent lipid peroxidation. The reactivation of APX at later stages appears to help reduce the lipid peroxidation rate, although the senescence program continues unabated.

A sensitive monoclonal antibody sandwich ELISA for the measurement of the major olive pollen allergen Ole e 1

BACKGROUND

Olive pollen is a major cause of inhalant allergy in countries around the Mediterranean sea. The major allergen of olive pollen is Ole e 1. Measurement of the major allergen content of allergen products for diagnosis and therapy is becoming an essential element of standardization protocols. This study aimed at the development of a monoclonal antibody (mAb) sandwich ELISA for Ole e 1.

METHODS

Balb/c mice immunized with Ole e 1 were used for the production of mAbs. Screening of mice and hybridomas was performed in a RIA with radiolabeled purified Ole e 1. Purified mAbs were used as catching and/or (biotinylated) detecting antibodies in sandwich ELISA.

RESULTS

Four mAbs (IgG1kappa) directed to nonoverlapping epitopes on Ole e 1 were obtained: 1A12, 5C1, 10A12 and 3H8. Both 1A12 and 10A12 were successfully used for affinity purification of Ole e 1 from olive pollen extract. Two sandwich ELISAs were developed, with 1A12 and 10A12 as catching, and 5C1 and 3H8 as detecting antibodies, respectively. Both catching and detecting antibodies were used in similar concentrations, ranging from 60 to 100 ng/well. For both ELISAs, the sensitivity was approximately 1 ng/ml of Ole e 1. The measuring range was from 1 to 25 ng/ml. No significant differences were observed, when the performance of both ELISAs in standardization of olive pollen extracts was compared.

CONCLUSIONS

Two sensitive sandwich ELISAs for the major olive pollen allergen Ole e 1 were developed. They will prove to be useful tools in allergen standardization protocols.

Ability of the 1992 and 1997 American Joint Committee on Cancer staging systems for prostate cancer to predict progression-free survival after radical prostatectomy for stage T2 disease

PURPOSE

In a revised 1997 edition the American Joint Committee on Cancer (AJCC) staging for prostate cancer reduced the subdivision of T2 disease from 3 (T2a, T2b and T2c) to 2 substages by combining single lobe disease (T2a and T2b) into a single stage, now termed T2a. We retrospectively reviewed a large series of men with clinically organ confined prostate cancer who underwent surgery by a single surgeon to determine how this change affected the ability of the staging system to predict outcome.

MATERIALS AND METHODS

Of 2, 293 cases treated with radical prostatectomy from 1982 to 1998, 1, 314 were clinically staged to have T2 disease. We analyzed the freedom from biochemical prostate specific antigen (PSA) progression after radical prostatectomy according to the 1992 and 1997 AJCC staging criteria.

RESULTS

Overall the actuarial 5 and 10-year biochemical progression-free survival rates for the whole group were 82% and 71%, respectively. The actuarial recurrence-free rate was significantly different for patients with 1992 AJCC T2a (T2a92) versus T2b (T2b92) disease (p <0.0001) but similar for those with 1992 T2b versus T2c (T2c92) disease (p = 0.1165). The actuarial recurrence-free rate was significantly different for patients with 1997 AJCC T2a (T2a97) versus T2b (T2b97) disease (p = 0.0001). However, the overall recurrence-free rate was lower in the T2a97 group compared with the T2a92 group.

CONCLUSIONS

The 1992 AJCC staging of T2 prostate cancer yielded a significant difference in the outcome of patients with single lobe disease (T2a92 and T2b92), which is obscured by the 1997 staging criteria. Therefore, we believe that the next revision of the AJCC staging system should revert back to the 1992 AJCC system of subdividing a single lobe disease category into T2a and T2b. Alternatively the committee may want to merge T2b92 and T2c92 stages into a new staging entity, since there was no statistical difference in the outcome of these 2 groups.

Catheter ablation of repetitive monomorphic ventricular tachycardia from left ventricular outflow tract guided by unipolar mapping

Repetitive monomorphic ventricular tachycardia from the left ventricular outflow tract is an uncommon arrhythmia. Successful catheter ablation has been previously reported in a few cases, but a large number of applications were usually needed when an approach based on either activation mapping or pace mapping was used. In our patient, the selection of the target point for application was based exclusively on unipolar mapping criteria of the ectopic beats, resulting in a short procedure with successful outcome.

Sequence and diversity of MHC DQA and DQB genes of the owl monkey Aotus nancymaae

The New World primate Aotus nancymaae has been recommended by the World Health Organization (WHO) as a model for evaluation of malaria vaccine candidates, given its susceptibility to experimental infection with the human malaria parasites Plasmodium falciparum and Plasmodium vivax. We present here the nucleotide sequences of the complete cDNA of MHC-DQA1 and of the polymorphic exon 2 segments of MHC-DQB1/DQB2. In a group of three nonrelated animals captured in the wild, five alleles of MHC-DQA1 could be identified. They all belong to one lineage, namely Aona-DQA1*27. This lineage has not been described in any other New World monkey species studied. In a group of 19 unrelated animals, 14 Aona-DQB1 alleles could be identified which are grouped into the two lineages Aona-DQB1*22 and Aona-DQB1*23. These lineages have been described previously in the common marmoset and cotton-top tamarin. In addition, two Aona-DQB2 sequences could be identified which are highly similar to HLA-DQB2 sequences. Essential amino acid residues contributing to MHC DQ peptide binding pockets number 1 and 4 are conserved or semi-conserved between HLA-DQ and Aona-DQ molecules, indicating a capacity to bind similar peptide repertoires. These results fully support the use of Aotus monkeys as an animal model for evaluation of future subunit vaccine candidates.

The effects of Tribulus terrestris on body composition and exercise performance in resistance-trained males

The purpose of this study was to determine the effects of the herbal preparation Tribulus terrestris (tribulus) on body composition and exercise performance in resistance-trained males. Fifteen subjects were randomly assigned to a placebo or tribulus (3.21 mg per kg body weight daily) group. Body weight, body composition, maximal strength, dietary intake, and mood states were determined before and after an 8-week exercise (periodized resistance training) and supplementation period. There were no changes in body weight, percentage fat, total body water, dietary intake, or mood states in either group. Muscle endurance (determined by the maximal number of repetitions at 100-200% of body weight) increased for the bench and leg press exercises in the placebo group (p <.05; bench press +/-28.4%, leg press +/-28.6%), while the tribulus group experienced an increase in leg press strength only (bench press +/-3.1%, not significant; leg press +/-28.6%, p <.05). Supplementation with tribulus does not enhance body composition or exercise performance in resistance-trained males.

Beta(1,2)-xylose and alpha(1,3)-fucose residues have a strong contribution in IgE binding to plant glycoallergens

Primary structures of the N-glycans of two major pollen allergens (Lol p 11 and Ole e 1) and a major peanut allergen (Ara h 1) were determined. Ole e 1 and Ara h 1 carried high mannose and complex N-glycans, whereas Lol p 11 carried only the complex. The complex structures all had a beta(1,2)-xylose linked to the core mannose. Substitution of the proximal N-acetylglucosamine with an alpha(1, 3)-fucose was observed on Lol p 11 and a minor fraction of Ole e 1 but not on Ara h 1. To elucidate the structural basis for IgE recognition of plant N-glycans, radioallergosorbent test analysis with protease digests of the three allergens and a panel of glycoproteins with known N-glycan structures was performed. It was demonstrated that both alpha(1,3)-fucose and beta(1,2)-xylose are involved in IgE binding. Surprisingly, xylose-specific IgE antibodies that bound to Lol p 11 and bromelain did not recognize closely related xylose-containing structures on horseradish peroxidase, phytohemeagglutinin, Ole e 1, and Ara h 1. On Lol p 11 and bromelain, the core beta-mannose is substituted with just an alpha(1,6)-mannose. On the other xylose-containing N-glycans, an additional alpha(1,3)-mannose is present. These observations indicate that IgE binding to xylose is sterically hampered by the presence of an alpha(1,3)-antenna.

Immunoglobulin kappa light-chain V, J, and C gene sequences of the owl monkey Aotus nancymaae

Sequences of Aotus nancymaae immunoglobulin kappa light-chain rearrangements were analyzed after reverse transcription polymerase chain reaction. Among 22 in-frame rearrangements analyzed, 12 IGKV genes belonging to the families 1, 2, or 3 were identified. Aotus counterparts for all five human IGKJ genes were found. The identity of the deduced human and Aotus amino acid sequences was between 83% and 92% for junctional regions and 74% for the constant region. Sequence comparisons between rearrangements indicated that somatic mutations, the addition of nongermline-encoded nucleotides, and exonuclease trimming contribute to the generation of diversity of Aotus immunoglobulin kappa chains. The high identity of Aotus and human IGK genes is comparable to that of T-cell receptor genes and further supports the proposal to use the Aotus Plasmodium falciparum infection model for the evaluation of malaria vaccine candidates.

Sequence and diversity of DRB genes of Aotus nancymaae, a primate model for human malaria parasites

The New World primate Aotus nancymaae is susceptible to infection with the human malaria parasite Plasmodium falciparum and Plasmodium vivax and has therefore been recommended by the World Health Organization as a model for evaluation of malaria vaccine candidates. We present here a first step in the molecular characterization of the major histocompatibility complex (MHC) class II DRB genes of Aotus nancymaae (owl monkey or night monkey) by nucleotide sequence analysis of the polymorphic exon 2 segments. In a group of 15 nonrelated animals captivated in the wild, 34 MHC DRB alleles could be identified. Six allelic lineages were detected, two of them having human counterparts, while two other lineages have not been described in any other New World monkey species studied. As in the common marmoset, the diversity of DRB alleles appears to have arisen largely by point mutations in the beta-pleated sheets and by frequent exchange of fixed sequence motifs in the alpha-helical portion. Pairs of alleles differing only at amino acid position b86 by an exchange of valine to glycine are present in Aotus, as in humans. Essential amino acid residues contributing to MHC DR peptide binding pockets number 1 and 4 are conserved or semiconserved between HLA-DR and Aona-DRB molecules, indicating a capacity to bind similar peptide repertoires. These results support fully our using Aotus monkeys as an animal model for evaluation of future subunit vaccine candidates.

Rib metastasis revealing hepatocellular carcinoma

Bone metastasis infrequently appears as the first manifestation of hepatocellular calcinoma (HCC), and in any case in most patients the primary tumour is detected a few months after its development. We report the case of a patient with alcoholic liver disease, increased levels of alpha-fetoprotein, and no evidence of hepatic lesion in the different imaging modalities, in whom metastasis of HCC was detected in the ribs, whereas the primary tumour was not diagnosed until 15 months later. We believe that all patients with increased levels of alpha-fetoprotein should be tested in an intensified search for HCC and possible metastases, given that hepatic lesions may not be detected until many months alter the diagnosis of metastatic disease.

Renal ablative cryosurgery in selected patients with peripheral renal masses

OBJECTIVES

To present the preliminary results of renal ablative cryosurgery in selected patients.

METHODS

Seven patients were treated, all of whom had small peripheral tumors and chose not to undergo partial or radical nephrectomy. Four patients underwent a rib-sparing flank incision; the remaining three underwent laparoscopy. All tumors were biopsied before cryoablation. Intraoperative ultrasound was used to monitor the cryolesion.

RESULTS

There were no intraoperative complications. The estimated blood loss averaged 111 mL. To date, 6 of the 7 patients have undergone at least one follow-up computed tomography scan (14.2 months average follow-up); all these scans demonstrated partial resolution of the lesion. Clinically, the patients tolerated the procedure without any renal complications or significant changes in creatinine.

CONCLUSIONS

This limited clinical trial has demonstrated the feasibility of treating small peripherally located renal tumors with cryosurgery with minimal morbidity and a favorable outcome. Further studies are necessary to determine the long-term efficacy of this treatment modality.

Fungi from geothermal soils in Yellowstone National Park

Geothermal soils near Amphitheater Springs in Yellowstone National Park were characterized by high temperatures (up to 70 degrees C), high heavy metal content, low pH values (down to pH 2.7), sparse vegetation, and limited organic carbon. From these soils we cultured 16 fungal species. Two of these species were thermophilic, and six were thermotolerant. We cultured only three of these species from nearby cool (0 to 22 degrees C) soils. Transect studies revealed that higher numbers of CFUs occurred in and below the root zone of the perennial plant Dichanthelium lanuginosum (hot springs panic grass). The dynamics of fungal CFUs in geothermal soil and nearby nongeothermal soil were investigated for 12 months by examining soil cores and in situ mesocosms. For all of the fungal species studied, the temperature of the soil from which the organisms were cultured corresponded with their optimum axenic growth temperature.

Evidence for early hematopoietic progenitor cell involvement in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) represents a subtype of acute myeloid leukemia with characteristic morphologic, molecular, and immunophenotypic features. Previous immunophenotypic analyses have shown that leukemic cells in APL typically express the myeloid markers CD33 and CD13 but lack expression of the early hematopoietic progenitor cell antigens CD34 and HLA-DR. We analyzed selected immunophenotypic features of APL by flow cytometry and showed that 7 (41%) of 17 cases contained significant subsets of CD34+ leukemic cells: CD34+ myeloid cells predominated in 2 APL cases. By using a fluorescence-activated cell sorter-fluorescence in situ hybridization approach, we confirmed that the CD34+ cells harbored the t(15;17) translocation characteristic of APL. By using the same experimental approach, CD34+ populations were stratified into primitive CD34+ CD38- and committed CD34+ CD38+ progenitor cell subpopulations; cells in both subsets contained the t(15;17) translocation. The knowledge that APL may be partly or largely CD34+ is important for proper diagnosis. Furthermore, identification of the t(15;17) translocation in CD34+ CD38- blasts indicates that, in at least some cases, the leukemogenic mutation in APL occurs within primitive hematopoietic progenitor cells.

Complex associations between HLA-DRB1 genes and female rheumatoid arthritis: results from a prospective study

We followed 138 Spanish patients (37 men and 101 women) with rheumatoid arthritis (RA) to analyze whether patient sex influenced the HLA-DRB1 associations with disease susceptibility. Results showed that, although a high increase of the shared epitope (SE) was observed in both genders, distribution of HLA-DRB1 specificities differs from males to females: DR1 was increased among male patients, whereas DR4 as well as DR10 were preferentially associated with female RA. To further explore whether this phenomenon operates either on susceptibility or on disease progression, 82 patients (25 males and 57 females) among the whole group were followed during the first 8 to 10 years of their disease. Results from this prospective study showed that the association of the SE with radiological disease severity was found in both male and female patients, although it was stronger among the latter group. Interestingly, DR1- as well as DR4-related alleles contributed to the high frequency of SE among female patients with early small-joints severe RA and/or long-term large-joint erosions. These results suggest that HLA polymorphism might be involved in RA pathogenesis through two mechanisms: (a) in combination with patient sex, operating in disease induction; and (b) independent of patient sex, influencing disease severity and progression.