Phosphorus availability drives mycorrhiza induced resistance in tomato

Arbuscular mycorrhizal (AM) symbiosis can provide multiple benefits to the host plant, including improved nutrition and protection against biotic stress. Mycorrhiza induced resistance (MIR) against pathogens and insect herbivores has been reported in different plant systems, but nutrient availability may influence the outcome of the interaction. Phosphorus (P) is a key nutrient for plants and insects, but also a regulatory factor for AM establishment and functioning. However, little is known about how AM symbiosis and P interact to regulate plant resistance to pests. Here, using the tomato-Funneliformis mosseae mycorrhizal system, we analyzed the effect of moderate differences in P fertilization on plant and pest performance, and on MIR against biotic stressors including the fungal pathogen Botrytis cinerea and the insect herbivore Spodoperta exigua. P fertilization impacted plant nutritional value, plant defenses, disease development and caterpillar survival, but these effects were modulated by the mycorrhizal status of the plant. Enhanced resistance of F. mosseae-inoculated plants against B. cinerea and S. exigua depended on P availability, as no protection was observed under the most P-limiting conditions. MIR was not directly explained by changes in the plant nutritional status nor to basal differences in defense-related phytohormones. Analysis of early plant defense responses to the damage associated molecules oligogalacturonides showed primed transcriptional activation of plant defenses occurring at intermediate P levels, but not under severe P limitation. The results show that P influences mycorrhizal priming of plant defenses and the resulting induced-resistance is dependent on P availability, and suggest that mycorrhiza fine-tunes the plant growth vs defense prioritization depending on P availability. Our results highlight how MIR is context dependent, thus unravel molecular mechanism based on plant defence in will contribute to improve the efficacy of mycorrhizal inoculants in crop protection.

Compatibility of mycorrhiza-induced resistance with viral and bacterial entomopathogens in the control of Spodoptera exigua in tomato

BACKGROUND

Arbuscular mycorrhizal fungi (AMF) are soil-borne microorganisms that establish mutualistic associations with roots of most terrestrial plants. This symbiosis results in nutritional and defensive benefits to the host plant, usually conferring protection against biotic stresses, but its indirect impact on third trophic levels is still unknown. In the present work, we explore whether the symbiosis of tomato plants with Funneliformis mosseae (and/or exposition to herbivory) influences the interaction of the generalist pest Spodoptera exigua (Lepidoptera: Noctuidae) with bacterial (Bacillus thuringiensis) and viral (baculovirus, SeMNPV) natural entomopathogens.

RESULTS

Symbiosis with AMF and previous herbivory reduces the relative growth of S. exigua, increases its susceptibility to a sublethal dose of B. thuringiensis and has positive or neutral impact on the lethality of SeMNPV. Reduction of the phenoloxidase activity, a marker of the insect immune response, was associated with the larval feeding on plant material previously exposed to herbivory but not to the AMF. In addition, no changes in the insect gut microbiota could be associated with the observed changes in larval growth and susceptibility to the entomopathogens.

CONCLUSION

Our findings provide the first evidence of compatibility of AMF symbiosis in tomato with the use of bacterial and viral entomopathogens, contributing to the development of novel approaches to combine the beneficial effect of AMF and entomopathogens in biological pest control. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Mycorrhizal symbiosis primes the accumulation of antiherbivore compounds and enhances herbivore mortality in tomato

Plant association with arbuscular mycorrhizal fungi (AMF) can increase their ability to overcome multiple stresses, but their impact on plant interactions with herbivorous insects is controversial. Here we show higher mortality of the leaf-chewer Spodoptera exigua when fed on tomato plants colonized by the AMF Funneliformis mosseae, evidencing mycorrhiza-induced resistance. In search of the underlying mechanisms, an untargeted metabolomic analysis through ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS) was performed. The results showed that mycorrhizal symbiosis had a very limited impact on the leaf metabolome in the absence of stress, but significantly modulated the response to herbivory in the damaged area. A cluster of over accumulated metabolites was identified in those leaflets damaged by S. exigua feeding in mycorrhizal plants, while unwounded distal leaflets responded similar to those from non-mycorrhizal plants. These primed-compounds were mostly related to alkaloids, fatty acid derivatives and phenylpropanoid-polyamine conjugates. The deleterious effect on larval survival of some of these compounds, including the alkaloid physostigmine, the fatty acid derivatives 4-oxododecanedioic acid and azelaic acid, was confirmed. Thus, our results evidence the impact of AMF on metabolic reprograming upon herbivory that leads to a primed accumulation of defensive compounds.

Mycorrhiza-Induced Resistance against Foliar Pathogens Is Uncoupled of Nutritional Effects under Different Light Intensities

The use of microbial inoculants, particularly arbuscular mycorrhizal fungi, has great potential for sustainable crop management, which aims to reduce the use of chemical fertilizers and pesticides. However, one of the major challenges of their use in agriculture is the variability of the inoculation effects in the field, partly because of the varying environmental conditions. Light intensity and quality affect plant growth and defense, but little is known about their impacts on the benefits of mycorrhizal symbioses. We tested the effects of five different light intensities on plant nutrition and resistance to the necrotrophic foliar pathogen Botrytis cinerea in mycorrhizal and non-mycorrhizal lettuce plants. Our results evidence that mycorrhiza establishment is strongly influenced by light intensity, both regarding the extension of root colonization and the abundance of fungal vesicles within the roots. Light intensity also had significant effects on plant growth, nutrient content, and resistance to the pathogen. The effect of the mycorrhizal symbiosis on plant growth and nutrient content depended on the light intensity, and mycorrhiza efficiently reduced disease incidence and severity under all light intensities. Thus, mycorrhiza-induced resistance can be uncoupled from mycorrhizal effects on plant nutrition. Therefore, mycorrhizal symbioses can be beneficial by providing biotic stress protection even in the absence of nutritional or growth benefits.

Differentiation of Trichuris species using a morphometric approach

Trichuris trichiura is a nematode considered as the whipworm present in humans and primates. The systematics of the genus Trichuris is complex. Morphological studies of Trichuris isolated from primates and humans conclude that the species infecting these hosts is the same. Furthermore, numerous molecular studies have been carried out so far to discriminate parasite species from humans and Non-Human Primates using molecular techniques, but these studies were not performed in combination with a parallel morphological study. The hypothesised existence of more species of Trichuris in primates opens the possibility to revise the zoonotic potential and host specificity of T. trichiura and other putative new species of whipworms.

In the present work, a study of Trichuris Roederer, 1761 (Nematoda:Trichuridae) parasitizing C. g. kikuyensis, P. ursinus, Macaca sylvanus, Pan troglodytes, and Sus scrofa domestica has been carried out using modern morphometric techniques in order to differentiate populations of Trichuris isolated from four species of captive NHP from different geographical regions, and swine, respectively.

The results obtained revealed strong support for geometrical morphometrics as a useful tool to differentiate male Trichuris populations. Therefore, morphometrics in combination with other techniques, such as molecular biology analyses, ought to be applied to further the differentiation of male populations.

On the other hand, morphometrics applied to female Trichuris species does not seem to contribute new information as all the measurements combinations of obtained from females always showed similar results.

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Geometrical morphometrics is an useful tool to differentiate male Trichuris populations.

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Geometrical morphometrics results are in agreement with the molecular biology analysis applied to the adult male samples that allow the identification of different species of Trichuris.

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The hypothesised existence of different species of Trichuris in primates opens the possibility to revise the zoonotic potential and host specificity of T. trichiura and other putative new species of whipworms.

Abstract P3-03-15: Patient reported outcomes in women undergoing sentinel lymph node biopsy in the SUNrISE randomized trial evaluating different doses of superparamagnetic iron oxide

Background. Sentinel lymph node biopsy (SLNB) with 2 mL of superparamagnetic iron oxide (SPIO) tracer has shown to be non-inferior to the standard radioisotope technique in several studies. The SUNrISE randomized trial has shown non inferiority of 1mL vs. 1.5 mL vs. 2 mL dose of SPIO with the standard use of radioisotope 99m Tc. We present patient reported outcomes from this randomized trial.

Material and methods. Patients with stage I breast cancer who underwent breast conservative surgery and sentinel lymph node biopsy were assigned consecutively (1:1:1) to one of the three groups defined by the different SPIO dose, group 1 (1mL), group 2 (1.5 mL) and group 3 (2 mL). Patients filled a questionnaire related to the presence of skin staining, staining intensity ( mild, moderate, intense) and whether the stain worried them. Patient also completed a quality of life (QoL) EORTC C30 questionnaire at 1 month postoperative visit, at 6 months and at 12 months. First analysis from the 1 month postoperative outcomes are reported here. Follow up on the 6 months will be available for the meeting.

Results. One hundred and thirty five patients were included in the trial, 45 in each group. Median age in group 1 was 58 years old, 63 y/o in group 2 and 65 y/o in group 3. (p=0.03) At 1 month follow up, patients in group 1 had less skin tattoo when compared with patients in group 2 and 3 (p= 0.02). There were no significant differences related to skin staining intensity by doses. Seventy percent of patients felt no concern about the tattoo.

On the multivariate analysis including age, SPIO dose, body mass index and breast density, only younger age (p = 0.037), and higher SPIO doses (p= 0.029) were significantly associated with increased skin staining.

There were no statistically significant differences in responses in the QoL questionnaire at 1 month postoperative visit. There were no severe reactions to the procedure or complications in any patient.

Conclusions. SLN with 1mL dose of SPIO has shown non-inferiority in the detection of SLN when compared to 1.5 and 2 mL. Being young and the use of 1.5 and 2 mL increased the risk of developing skin staining. Even though, most of the patients were not concern about the skin staining. Rates of discontinuation of skin discoloration will be assessed at 6 months follow up.

Citation Format: Rubio IT, Esgueva A, Espinosa-Bravo M, Rodriguez-Revuelto R, Siso C, Rivero J. Patient reported outcomes in women undergoing sentinel lymph node biopsy in the SUNrISE randomized trial evaluating different doses of superparamagnetic iron oxide [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-15.

Root metabolic plasticity underlies functional diversity in mycorrhiza-enhanced stress tolerance in tomato

Arbuscular mycorrhizal (AM) symbioses can improve plant tolerance to multiple stresses. We compared three AM fungi (AMF) from different genera, one of them isolated from a dry and saline environment, in terms of their ability to increase tomato tolerance to moderate or severe drought or salt stress. Plant physiological parameters and metabolic profiles were compared in order to find the molecular mechanisms underlying plant protection against stress. Mycorrhizal growth response was determined, and ultrahigh-performance LC-MS was used to compare the metabolic profile of plants under the different treatments. All AMF increased plant tolerance to stress, and the positive effects of the symbiosis were correlated with the severity of the stress. The AMF isolated from the stressful environment was the most effective in improving plant tolerance to salt stress. Differentially accumulated compounds were identified and the antistress properties of some of them were confirmed. We demonstrate that AM symbioses increase plant metabolic plasticity to cope with stress. Some responses were common to all AMF tested, while others were specifically related to particular isolates. Important metabolism reprograming was evidenced upon salt stress, and we identified metabolic pathways and compounds differentially accumulated in mycorrhizas that may underlie their enhanced tolerance to stress.

Safety and Immunogenicity of a Human Epidermal Growth Factor Receptor 1 (HER1)-Based Vaccine in Prostate Castration-Resistant Carcinoma Patients: A Dose-Escalation Phase I Study Trial

Metastatic castration-resistant prostate cancer (CRPC) remains incurable due to the lack of effective therapies. Activation of the human epidermal growth factor receptor 1 (HER1) in prostate cancer contributes to metastatic progression as well as to disease relapse. Here, we determined the toxicity and immunogenicity of a HER1-based cancer vaccine in CRPC patients included in a phase I clinical trial. CRPC patients (n = 24) were intramuscularly vaccinated with HER1 vaccine consisting of the extracellular domain of HER1 molecule (ECD) and very small size proteoliposome from Neisseria meningitidis (VSSP) and Montanide ISA-51 VG as adjuvants. Patients were included in five groups according to the vaccine dose (100, 200, 400, 600, and 800 μg). The primary endpoints were safety and immunogenicity. The anti-HER1 antibodies were measured by an ELISA, the recognition of an HER1 positive tumor cell line and the inhibition of HER1 phosphorylation by sera were determined by flow cytometry and western blot analysis, respectively. The HER1-specific T cell response was assessed by determination of IFN-γ-producing T cells using ELISpot assay. The vaccine was well tolerated. No grade III or IV adverse events were reported. High titers of anti-HER1 antibodies were observed in most of the evaluated patients. There were no significant differences regarding the geometric means of the anti-HER1 titers among the dose groups except the group of 100 μg in which antibody titers were significantly lower. A Th1-type IgG subclasses pattern was predominant in most patients. Only patients receiving the higher doses of vaccine showed significant tumor cell recognition and HER1 phosphorylation inhibition by hyperimmune sera. Forty two percent of the patients showed a specific T cell response against HER1 peptides pool in post-treatment samples. There was a trend toward survival benefit in those patients showing high anti-HER1 specific antibody titers and a significant association between cellular immune response and clinical outcome.

Avaliação da progênie de ovelhas Merino Australiano cruzadas com carneiro Dorper ou Southdown

O presente estudo objetivou avaliar o efeito do genótipo do carneiro (Dorper ou Southdown), do sexo e do tipo de parto sobre características de crescimento de 268 cordeiros filhos de ovelhas Merino Australiano. Até o desmame, todos os animais permaneceram sobre pastagem de trevo-vermelho (Trifolium pratense ), chicória (Cychorium intibus ), trevo-branco (Trifolium repens ), festuca (Festuca arundinacea ) e azevém (Lolium multiflorum ), com carga animal de 10 ovelhas com seus cordeiros/ha. A partir do desmame (29,95±4,94kg de peso vivo e 109,45±7,41 dias de idade), os cordeiros permaneceram sobre a mesma pastagem utilizada durante a lactação, sendo terminados posteriormente sobre um cultivo de soja (Glycine max) , com carga animal de 30 cordeiros/ha. Não foi verificado efeito do genótipo do carneiro (P>0,05) sobre nenhuma das variáveis analisadas. Por outro lado, do nascimento ao desmame e do desmame até o embarque dos cordeiros para abate, os machos (criptorquidas) apresentaram ganhos de peso diário superiores (241 e 212g/dia; 121 e 94g/dia, para machos e fêmeas, respectivamente; P≤0,001), o que proporcionou um peso vivo ao embarque 14,9% superior em relação às fêmeas (40,89 e 35,59kg, para machos e fêmeas, respectivamente; P≤0,001). Os cordeiros de parto simples apresentaram maiores (P≤0,001) pesos vivos e medidas corporais ao nascimento, bem como maior velocidade de crescimento até o desmame (239 e 214g/dia, parto simples e duplo, respectivamente; P≤0,001). Porém, após o desmame, os cordeiros de parto duplo apresentaram maior ganho de peso (98 e 117g/dia) (P≤0,05) e uma superioridade (P≤0,001) em quilogramas de cordeiros desmamados (26,80 e 49,61kg) ou embarcados (33,91 e 64,69kg) por ovelha parida. Independentemente do sexo e do tipo de parto, todos os cordeiros superaram as exigências de peso e condição corporal mínima requerida para comercialização de cordeiros pesados no Uruguai, na metade do tempo que em média ocorre com os genótipos tradicionais.

In vitro evaluation of oestrogenic/androgenic activity of the serum organochlorine pesticide mixtures previously described in a breast cancer case-control study

Some organochlorine pesticides (OCs) have been individually linked to breast cancer (BC) because they exert oestrogenic effects on mammary cells. However, humans are environmentally exposed to more or less complex mixtures of these organochlorines, and the biological effects of these mixtures must be elucidated. In this work we evaluated the in vitro effects exerted on human BC cells by the OC mixtures that were most frequently detected in two groups of women who participated in a BC case-control study developed in Spain: healthy women and women diagnosed with BC. The cytotoxicity, oestrogenicity, and androgenicity of the most prevalent OC mixtures found in healthy women (H-mixture) and in BC patients (BC-mixture) were tested at concentrations that resembled those found in the serum of the evaluated women. Our results showed that both OC mixtures presented a similar oestrogenic activity and effect on cell viability, but BC-mixture showed an additional anti-androgenic effect. These results indicate that although the proliferative effect exerted by these mixtures on human breast cells seems to depend mainly on their oestrogenic action, the BC-mixture might additionally induce cell proliferation due to its anti-androgenic activity, therefore increasing the carcinogenic potential of this mixture. The findings of this study demonstrate that subtle variations in the composition of a mixture may induce relevant changes in its biological action.

Matrizes ovinas cruzadas são sempre mais eficientes do que as matrizes puras?

Foi estudado o desempenho reprodutivo de 482 ovelhas multíparas (3/4 Texel x 1/4 Corriedale: TXC, 1/2 Romney Marsh x 1/2 Corriedale: RMC, 3/4 Poll Dorset x 1/4 Corriedale: PDC, 1/2 Finnish Landrace x 1/2 Merino Australiano: FLMA e Merino Australiano puras: MA), as características do crescimento de 585 cordeiros provenientes de carneiros Dorper e ovelhas: TXC (n = 68); RMC (n = 64); PDC (n = 68); FLMA (n = 183) e MA (n = 202) e os quilogramas de carne de cordeiros produzidos/kg de ovelha colocadas em cobertura (como indicador de eficiência), pastoreando campo natural e pastagens cultivadas. As ovelhas FLMA e TXC apresentaram as maiores taxas de parição (167,89 e 174,36%, respectivamente) em relação às demais cruzas, as quais não diferiram entre si (121,43 e 125,49%, PDC e RMC, respectivamente; P>0,05), porém foram superiores as MA (88,99%), sendo esse resultado uma consequência da maior quantidade de cordeiros nascidos/ovelha parida, que influenciou mais do que sua maior taxa de fertilidade. O genótipo da ovelha também afetou (P<0,0001) o crescimento dos cordeiros até o momento da sua venda com 41,6 ±6,7kg aos 206±7,25 dias de idade. Os cordeiros filhos das ovelhas TXC, PDC e RMC apresentaram maiores ganhos de peso diário que os filhos de FLMA, e esses maiores do que os MA. No entanto, de todas as cruzas avaliadas, somente a FLMA foi mais eficiente que a MA.

Metabolic transition in mycorrhizal tomato roots

Beneficial plant-microorganism interactions are widespread in nature. Among them, the symbiosis between plant roots and arbuscular mycorrhizal fungi (AMF) is of major importance, commonly improving host nutrition and tolerance against environmental and biotic challenges. Metabolic changes were observed in a well-established symbiosis between tomato and two common AMF: Rhizophagus irregularis and Funneliformis mosseae. Principal component analysis of metabolites, determined by non-targeted liquid chromatography-mass spectrometry, showed a strong metabolic rearrangement in mycorrhizal roots. There was generally a negative impact of mycorrhizal symbiosis on amino acid content, mainly on those involved in the biosynthesis of phenylpropanoids. On the other hand, many intermediaries in amino acid and sugar metabolism and the oxylipin pathway were among the compounds accumulating more in mycorrhizal roots. The metabolic reprogramming also affected other pathways in the secondary metabolism, mainly phenyl alcohols (lignins and lignans) and vitamins. The results showed that source metabolites of these pathways decreased in mycorrhizal roots, whilst the products derived from α-linolenic and amino acids presented higher concentrations in AMF-colonized roots. Mycorrhization therefore increased the flux into those pathways. Venn-diagram analysis showed that there are many induced signals shared by both mycorrhizal interactions, pointing to general mycorrhiza-associated changes in the tomato metabolome. Moreover, fungus-specific fingerprints were also found, suggesting that specific molecular alterations may underlie the reported functional diversity of the symbiosis. Since most positively regulated pathways were related to stress response mechanisms, their potential contribution to improved host stress tolerance is discussed.

Comparison of surface integral equation formulations for electromagnetic analysis of plasmonic nanoscatterers

The performance of most widespread surface integral equation (SIE) formulations with the method of moments (MoM) are studied in the context of plasmonic materials. Although not yet widespread in optics, SIE-MoM approaches bring important advantages for the rigorous analysis of penetrable plasmonic bodies. Criteria such as accuracy in near and far field calculations, iterative convergence and reliability are addressed to assess the suitability of these formulations in the field of plasmonics.

Solution of large-scale plasmonic problems with the multilevel fast multipole algorithm

A surface integral equation together with the multilevel fast multipole algorithm is successfully applied to fast and accurate resolution of plasmonic problems involving a large number of unknowns. The absorption, scattering, and extinction efficiencies of several plasmonic gold spheres of increasing size are efficiently obtained solving the electric and magnetic current combined-field integral equation. The numerical predictions are compared with reference analytic results to demonstrate the accuracy, suitability, and capabilities of this approach when dealing with large-scale plasmonic problems.

Method-of-moments formulation for the analysis of plasmonic nano-optical antennas

We present a surface integral equation (SIE) to model the electromagnetic behavior of metallic objects at optical frequencies. The electric and magnetic current combined field integral equation considering both tangential and normal equations is applied. The SIE is solved by using a method-of-moments (MoM) formulation. The SIE-MoM approach is applied only on the material boundary surfaces and interfaces, avoiding the cumbersome volumetric discretization of the objects and the surrounding space required in differential-equation formulations. Some canonical examples have been analyzed, and the results have been compared with analytical reference solutions in order to prove the accuracy of the proposed method. Finally, two plasmonic Yagi-Uda nanoantennas have been analyzed, illustrating the applicability of the method to the solution of real plasmonic problems.

Surface integral equation formulation for the analysis of left-handed metamaterials

A surface integral equation (SIE) formulation is applied to the analysis of electromagnetic problems involving three-dimensional (3D) piecewise homogenized left-handed metamaterials (LHM). The resulting integral equations are discretized by the well-known method of moments (MoM) and solved via an iterative process. The unknowns are defined only on the interfaces between different media, avoiding the discretization of volumes and surrounding space, which entails a drastic reduction in the number of unknowns arising in the numerical discretization of the equations. Besides, the SIE-MoM formulation inherently includes the radiation condition at infinity, so it is not necessary to artificially include termination absorbing boundary conditions. Some 3D numerical examples are presented to confirm the validity and versatility of this approach on dealing with LHM, also providing some intuitive verifications of the singular properties of these amazing materials.

Predictive factors in advanced head and neck cancer treated by radio-chemotherapy and hypoxia modification

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Background: Anemia and tumor hypoxia are known factors for resistance to radio-chemotherapy (RT-CT). In a previous report we have suggested that spinal cord stimulation (SCS) can modify tumor oxygenation and regional blood flow in head and neck cancer (HNC). The aim of the present prospective study was to test the predictive value of pO2 measurement in HNC treated by RT-CT and hypoxia modification using SCS. Methods: Twelve male patients with advanced HNC were analyzed. Stage IVb-IVa: 8–4; mean age 58 + 7.6 years (46–70). Scheduled therapy was hyperfractionated RT (120 cGy/fraction, two fractions/day, total dose 81.6 Gy) from a Co- 60 source, and tegafur 800 mg/day. SCS devices were placed before RT-CT under local anesthesia. During treatment, SCS was connected from 20–30 min before to 20–30 min after each radiotherapy session. Before treatment, they were assessed: Hemoglobin levels and tumor oxygenation pre-SCS and pos-SCS (measured by a polarographic probe system ‘pO2 Histograph‘), expressed as median-pO2, and the fraction of pO2 values less than 5 mmHg (HF5) and less than 2.5 mmHg (HF2.5). Correlations were assessed using Pearson and Spearman tests, and actuarial survival using Kaplan-Meier estimates and Log-rank test. Results: Hemoglobin levels were correlated with oxygenation pre-SCS and pos-SCS: median-pO2 (p=0.005 and p=0.011), HF5 (p=0.048 and p=0.005) respectively. Anemia was associated with more advanced stage (IVb vs IVa, p=0.022), higher HF5 pos-SCS (p=0.028) and lower disease-free survival (p=0.019). The HF2.5 pos-SCS was adversely correlated with the 2 years actuarial: disease-free survival (p=0.027), cause-specific survival (p=0.008) and overall survival (p=0.008). HF2.5 was also correlated with hematocrit (p=0.044). Conclusions: Low hemoglobin levels and anemia are associated with more hypoxic and more advanced tumors. Pre-treatment tumor hypoxia (assessed by the fraction of pO2 values less than 2.5 mmHg during-SCS) is a strong predictive factor for survival in advanced HNC. Patients with highly hypoxic tumors should be selected for more aggressive treatments. Partially supported by: Grant ‘FUNCIS: PI 31–98‘. Scientific supervision was carried out by GICOR.

No significant financial relationships to disclose.

Effect of cervical spinal cord stimulation on regional blood flow and oxygenation in advanced head and neck tumours

BACKGROUND

Tumour ischaemia leads to decreased delivery of oxygen, chemotherapy and radiosensitisers. Hypoxia in head and neck (H&N) tumours is an important adverse prognostic factor. Spinal cord stimulation (SCS) is a well-established neurosurgical technique in the treatment of several ischaemic syndromes. This prospective study evaluated the effect of cervical-SCS on common carotid artery (CCA) blood flow and tumour oxygenation in patients with advanced H&N cancer.

PATIENTS AND METHODS

Sixteen patients with advanced H&N tumours were enrolled. Cervical-SCS devices were inserted subcutaneously prior to commencement of scheduled chemoradiotherapy. Pre- and post-SCS measurements were as follows: (i) tumour oxygenation (mmHg) using polarographic probes; (ii) blood flow quantification (ml/min) and diastolic and systolic velocimetry (cm/s) in the CCA using colour Doppler.

RESULTS

After SCS, median tumour oxygenation increased in two-thirds of patients (34%; P = 0.023), all patients had improved CCA blood flow (50%; P <0.001) and almost all patients showed an increased CCA diastolic velocity (26%; P = 0.003) and systolic velocity (20%; P = 0.011).

CONCLUSIONS

Cervical-SCS increased tumour oxygenation and CCA blood flow, and could enhance the loco-regional delivery of oxygen, radiosensitising and chemotherapeutic drugs. Cervical-SCS as adjuvant in chemoradiotherapy of these tumours warrants further investigation.

Chimeric synthetic peptides from the nucleocapsid p24 protein of human immunodeficiency virus type-1

Two chimeric synthetic peptides incorporating antigenic sequences from N-terminal (peptide C14) (134-163) and C-terminal (peptide C15) (335-364) of the p24 protein of human immunodefiency virus (HIV- 1), were synthesized. Peptides C14-GG-C15 and C15-GG-C14 represented sequences from the p24 protein in both possible orders, separated by two glycine residues as arm spacers. These peptides were evaluated as antigen in an Ultramicroenzyme-linked immunosorbent assay (UMELISA) using sera of HIV-1-infected individuals (n = 16) with different titers of antibodies and the specificity was evaluated with healthy blood donors (n = 20). The results were compared to plates coated with monomeric peptides C14 and C15. The chimeric peptide C14-GG-C15 was the most antigenic. Those results may be related to the peptide structure, the sequence order in the chimeric peptide, and epitope accessibility to the antibodies. This chimeric peptide would be very useful for HIV-1 diagnostics.

Hepatitis B virus exposure in human immunodeficiency virus seropositive Cuban patients

In order to estimate the prevalence of serological markers of exposure to Hepatitis B Virus (HBV), 295 subjects were selected at random from the National Registry of human immunodeficiency virus positive subjects. Evidence of exposure to HBV was defined as: testing Hepatitis B surface antigen (HBsAg) and anti-Hepatitis B core antigen (anti-HBc) positive or anti-HBc positive only. Overall, 133 (45.5%) were positive for anti-HBc and 15 (5.1%) resulted positive to HBsAg. Significant statistical association was found between male sex and exposure to HBV (p<0.01). Homosexual or bisexual behavior was found to be strongly associated to HBV exposure (p<0.001). In conclusion, the prevalence of HBV serological markers is higher in Cuban HIV positive subjects compared to the Cuban general population.

[Facial nerve anomaly. A morphohistological study. Apropos a case]

A malformation of the facial nerve in the temporal bone of an otherwise normal adult is reported. The abnormality consisted in the facial nerve obstructing the oval window in the second part of its intrapetrosal section.

[Polyps, nodules, and Reinke edema. An epidemiological and histopathological study]

A retrospective epidemiological and histopathological review was made of 258 patients. Forty had laryngeal polyps, 35 vocal fold nodules, and 41 Reinke edema. One hundred forty-two records were excluded for lack of epidemiological or histopathological data. No dysplastic changes were observed in nodules or polyps. One patient with edema had mild dysplasia. The epidemiological data showed that voice abuse or misuse was the main factor in patients with vocal fold nodules; smoking was the main factor in polyps and edema.

Circulating cell adhesion molecules are correlated with ultrasound-based assessment of carotid atherosclerosis

Although cellular adhesion molecules (CAMs) are hypothesized to play an important role in atherogenesis, the relationship between CAMs and systemic atherosclerosis is uncertain. Among 92 outpatients (48 men; mean+/-SD age, 65+/-9 years), we evaluated the association of soluble vascular CAM-1 (sVCAM-1) and intercellular adhesion molecule-1 (sICAM-1) with carotid intimal-medial thickness (IMT), an index of early atherosclerosis. All subjects underwent a 2-dimensional ultrasound examination of both carotid arteries at the distal common carotid arteries and bifurcation. sVCAM-1 and sICAM-1 levels measured by enzyme-linked immunosorbent assay were significantly correlated with mean IMT of the common carotid artery (r=0.34 and r=0.30, respectively; P<0.01) and carotid bifurcation (r=0.31 and r=0.26, respectively; P<0.05), whereas sVCAM-1 was also positively associated with maximal carotid IMT (r=0.35, P<0.01). Adjustment for age attenuated the association between sVCAM-1 and common (r=0.16, P=0.13) and bifurcation (r=0.18, P=0.07) carotid IMT but had minimal effect on the associations between sICAM-1 and carotid measurements (r=0.32, P<0.01; r=0.23, P<0.05; for common and bifurcation IMT, respectively). Age-adjusted sICAM-1 levels increased in a stepwise fashion across common carotid IMT tertiles (253+/-27 versus 275+/-24 versus 384+/-26 pg/mL for the lowest, intermediate, and highest IMT tertiles, respectively; P<0.01). A similar trend was also found between sVCAM-1 levels and common carotid IMT tertiles (625+/-60 versus 650+/-53 versus 714+/-58 pg/mL; P<0.15). These associations were minimally affected in analyses adjusting for hypertension, diabetes, smoking, low and high density lipoprotein cholesterol, lipoprotein(a), and homocysteine, or in a subgroup analysis limited to those with no prior history of atherothrombotic disease. These data demonstrate a positive association between serum CAMs with carotid IMT and further support the hypothesis that systemic inflammation may have a role in atherosclerotic lesion development.

Influence of mechanical ventilation on blood lactate in patients with acute respiratory failure

OBJECTIVES

To determine whether mechanical ventilation (MV) may affect blood lactate concentration in patients with acute respiratory failure.

DESIGN

Prospective observational study with follow-up to hospital discharge.

SETTING

A 17-bed medical and coronary intensive care unit in a 650-bed general hospital.

PATIENTS

55 adult patients mechanically ventilated for acute respiratory failure between May 1996 and April 1997 were recruited.

MEASUREMENTS AND RESULTS

Arterial blood samples for determination of plasma lactate and blood gas analysis were taken just before tracheal intubation on spontaneous breathing, and 20 and 60 min after the initiation of controlled MV. Cuff systemic arterial pressure was measured before tracheal intubation and every 10 min during the first h of MV. Hyperlactatemia (arterial blood lactate > or = 2 mmol/l) was present in 21 of the 55 patients studied. After 20 min of MV, there was a decrease in blood lactate from 4.74 +/- 1.78 to 3.07 +/- 1.69 mmol/l (p < 0.01); 40 min later there was a further decrease to 2.63 +/- 1.35 mmol/l (p < 0.05). The decrease in blood lactate was also observed in those patients who after starting MV developed systemic arterial hypotension (p < 0.01). In patients with a normal lactate concentration at the entry to the study, lactate remained the same after 60 min on MV (NS).

CONCLUSIONS

Controlled MV decreases substantially the severity of hyperlactatemia in patients with acute respiratory failure, and any adverse circulatory effects of MV do not alter this beneficial outcome.

[Follow-up serological study of herpes simplex and cytomegalovirus in Cuban patients infected with human immunodeficiency virus (HIV)]

The evolution serological response against the herpes simplex virus and citomegalovirus in HIV infected patients grouped into different stages of the disease was studied. Fluctuations in the TPG of antibodies were observed in these values in a cyclical way through time. There was a greater significant difference among the TPG of antibodies against HSV in the group of asymptomatic patients compared with AIDS patients and with those who died. There is a marked decrease in the TPG of antibodies against HSV and CMV approximately one year before the death of patients.

Evaluation of the serologic response against two consensus V3 loop peptides from human immunodeficiency virus-1 in Cuban patients

OBJECTIVES

A retrospective study was conducted to evaluate the antibody response of Cuban patients infected with human immunodeficiency virus (HIV)-1 against two consensus peptides from the third variable domain (V3) loop of glycoprotein gp120.

METHODS

The study included sera from 10 individuals at different stages of disease. Two 15-meric synthetic peptides designed from a consensus sequence, belonging to group B or C of HIV-1, were used to determine antibody titers and avidity indexes in an indirect enzyme-linked immunoassay.

RESULTS

A high reactivity against both peptides was detected, with 80% of the sera reacting with at least one of the peptides. The antibody titers and avidity indexes did not correlate with disease progression. Additionally, for one of the patients from whom the virus had been isolated, a higher avidity index was found against the homologous peptide.

CONCLUSIONS

This study showed high reactivity against two consensus peptides from the V3 loop of gp120 among patients with HIV. Large scale studies are needed to determine whether the titers or avidity of anti-V3 antibodies, at the early stages of infection, are predictive of disease progression. Both peptides are candidates for inclusion in experimental vaccines.

Use of antipsychotic drugs in nursing homes: current compliance with OBRA regulations

OBJECTIVE

To examine the degree and patterns of compliance with the Omnibus Budget Reconciliation Act (OBRA) regulations regarding the use of antipsychotic drugs in nursing homes.

DESIGN

Retrospective chart review of all resident records.

PARTICIPANTS

Eight nursing homes: five community, two county-owned, and one university-affiliated Veterans Administration facility.

MEASUREMENTS

A structured assessment instrument to track compliance with each aspect of the OBRA regulations regarding antipsychotic drug use.

RESULTS

A total of 1573 nursing home residents' pharmacy records were reviewed between August 1994 and March 1996. Two hundred seventy-nine residents were actively taking antipsychotic medications (prevalence = 17.7%). Mean compliance greater than 70% was found for (1) appropriate diagnostic indication (mean = 70.9%), (2) dosage within recommended limits (mean = 90.1%), and 3) documented appropriate target symptoms (mean = 90.4%). Dosages were more likely to exceed limits in those patients with histories of major mental illness, particularly schizophrenia.

CONCLUSIONS

Nursing homes were better able to comply with those guidelines that are most specific. Educational interventions now need to focus on behavioral interventions, monitoring of adverse effects, and efficacy. These data are useful in establishing threshold levels of performance and can be used by nursing homes for continuous quality improvement. OBRA continues to impact neuroleptic drug prescribing practices in nursing homes significantly.

A recombinant protein based immunoassay for the combined detection of antibodies to HIV-1, HIV-2 and HTLV-I

The aim of this study was to develop and evaluate a combined assay for the detection of antibodies to HIV-1, HIV-2 and HTLV-I (human T-cell leukemia virus type I). A mixture of recombinant proteins and synthetic peptides was fixed to the surface of microELISA wells and a protein A peroxidase conjugate was used as tracer. The combined assay was compared to specific HIV-1/2 and HTLV-I commercial ELISAs. The sensitivity was studied with a panel of 158 HIV-1, 82 HIV-2 and 48 HTLV-I positive sera, all of which were reactive in the combined assay. The analytical sensitivity was studied with a panel of serially diluted sera and was similar to that obtained for the specific ELISAs. The specificity of the test was 99.78% against a panel of 466 negative sera collected from voluntary donors that included HBsAg, HCV, and VDRL positive sera. The false positive serum was borderline in the HTLV-I specific ELISA. The new combined ELISA can be used as an efficient initial screening assay, avoiding the cost of individual tests for HIV and HTLV.

Long-term treatment with recombinant interferon alpha-2b prolongs survival of asymptomatic HIV-infected individuals

RATIONALE AND OBJECTIVE

Early long-term treatment with recombinant interferon (IFN) alpha-2b delayed disease progression in asymptomatic Human Immunodeficiency Virus (HIV) carriers in a randomized trial that lasted from October 1987 to February 1992 (14). The aim of the work reported in this paper was to observe if there was also an effect on survival when the same patients were followed-up further.

DESIGN AND INTERVENTIONS

IFN alpha-2b was given 3 x 10(6) IU, 3 times weekly. The control group did not receive any treatment. The main end-point for this evaluation was death due to any cause. The deadline was August 1995.

POPULATION

Subjects were anti-HIV-1 seropositive, Western blot-confirmed, asymptomatic (CDC group II), or with generalized lymphadenopathies (CDC group III). The groups had 79 (control) and 83 (IFN) patients.

MAIN RESULTS

Mean survival was longer in the IFN group (95% CI: 127-152 vs. 101-120 months since infection or 80-90 vs. 70-82 months since the start of treatment). Survival rates were higher in IFN-treated individuals (61-77% vs. 24-54% at 10 years of infection or 53-69% vs. 34-52% at 7 years of treatment or follow-up). It was also confirmed that disease progression is significantly slower in IFN-treated patients. There were 23.4 vs. 3.2% long-term survivors in the IFN and control groups, respectively (p = 0.005). IFN-treated patients had fewer AIDS-related malignancies (5 vs. 11), mainly Kaposi's sarcomas (1 vs. 5). This difference was not statistically significant, but clinically interesting. There was no difference in survival if measured since the onset of AIDS.

CONCLUSION

IFN alpha treatment given from the early stages of infection, but not after the appearance of AIDS symptoms, can prolong survival.

Single point dilution method for the quantitative analysis of antibodies to the gag24 protein of HIV-1

In the present work a concept proposed in 1992 by Dopotka and Giesendorf was applied to the quantitative analysis of antibodies to the p24 protein of HIV-1 in infected asymptomatic individuals and AIDS patients. Two approaches were analyzed, a linear model OD = b0 + b1.log(titer) and a nonlinear log(titer) = alpha.OD beta, similar to the Dopotka-Giesendorf's model. The above two proposed models adequately fit the dependence of the optical density values at a single point dilution, and titers achieved by the end point dilution method (EPDM). Nevertheless, the nonlinear model better fits the experimental data, according to residuals analysis. Classical EPDM was compared with the new single point dilution method (SPDM) using both models. The best correlation between titers calculated using both models and titers achieved by EPDM was obtained with the nonlinear model. The correlation coefficients for the nonlinear and linear models were r = 0.85 and r = 0.77, respectively. A new correction factor was introduced into the nonlinear model and this reduced the day-to-day variation of titer values. In general, SPDM saves time, reagents and is more precise and sensitive to changes in antibody levels, and therefore has a higher resolution than EPDM.

Cytotoxicity of a low molecular weight fraction from Aloe vera (Aloe barbadensis Miller) gel

The cytotoxicity of a low mol. wt fraction (LMWF) obtained from Aloe vera gel was determined by two different assays. Firstly, exposure of monolayers of chicken fibroblasts to LMWF induced disruption of intercellular junctions and detachment of individual cells from the bottom of the flask, with formation of cell-free gaps in the monolayer. Secondly, LMWF inhibited the production of reactive oxygen species by human polymorphonuclear leukocytes stimulated by zymosan, as followed by luminol-dependent chemiluminescence. The toxic activity of LMWF was compared to that of sodium dodecyl sulfate (a well-known toxic substance), aloe-emodin and aloin (an anthraquinone and its precursor present in Aloe vera cortex) using the chemilumescence assay, and was found to be of similar potency to these toxic substances on a weight-to-weight basis. These results confirm that Aloe vera gel contains toxic low mol. wt compounds, and every effort must be made to limit the amount of these toxins in the commercially prepared Aloe vera gel products.

Incidence of dehiscences in the fallopian canal

Fifty human temporal bones from necropsies were used to study the frequency of canal dehiscences in detail along the course of the facial nerve. Specifically, the study focused on bony dehiscences in the fallopian canal and vascular communications between the facial nerve and the surrounding bone. High frequency of dehiscences at the oval window (60%) and in the pyramidal segment (54%) were found. These dehiscence rates are in agreement with published reports. A 20% rate of dehiscences at the most anterior segment of the tympanic segment was noted and a non-reported high rate (20%) of multiple dehiscences along the course of the fallopian canal in the same temporal bone in specimens of newborns and young children. The significance of these findings in terms of clinical implications is discussed.

Multiparametric bifurcations for a model in epidemiology

In the present paper we make a bifurcation analysis of an SIRS epidemiological model depending on all parameters. In particular we are interested in codimension-2 bifurcations.

Histological structure of the vocal fold in the human larynx

Histological analysis of the human vocal folds, focused particularly on the lamina propria of the vocal muscle of fetuses, infants, and adults in horizontal laryngeal sections, allowed us to show the differences in morphology and composition according to the laryngeal development. Our results indicate that the origin of the vocal fold is independent of the origin of the other portions of the larynx, and the influence of the zone known as macula flava in the maturation of the vocal fold is an age-related process.