Meta-analysis of the Microbial Diversity Cultured in Bioreactors Simulating the Gut Microbiome

Understanding the intricate ecological interactions within the gut microbiome and unravelling its impact on human health is a challenging task. Bioreactors are valuable tools that have contributed to our understanding of gut microbial ecology. However, there is a lack of studies describing and comparing the microbial diversity cultivated in these models. This knowledge is crucial for refining current models to reflect the gastrointestinal microbiome accurately. In this study, we analysed the microbial diversity of 1512 samples from 18 studies available in public repositories that employed cultures performed in batches and various bioreactor models to cultivate faecal microbiota. Community structure comparison between samples using t-distributed stochastic neighbour embedding and the Hellinger distance revealed a high variation between projects. The main driver of these differences was the inter-individual variation between the donor faecal inocula. Moreover, there was no overlap in the structure of the microbial communities between studies using the same bioreactor platform. In addition, α-diversity analysis using Hill numbers showed that highly complex bioreactors did not exhibit higher diversities than simpler designs. However, analyses of five projects in which the samples from the faecal inoculum were also provided revealed an amplicon sequence variants enrichment in bioreactors compared to the inoculum. Finally, a comparative analysis of the taxonomy of the families detected in the projects and the GMRepo database revealed bacterial families exclusively found in the bioreactor models. These findings highlight the potential of bioreactors to enrich low-abundance microorganisms from faecal samples, contributing to uncovering the gut microbial "dark matter".

Effect of Ecuadorian natural zeolite on the performance of anaerobic digestion of swine waste in semicontinuous regime

This study explores the potential of zeolite as an amendment to mitigate ammonium inhibition in the anaerobic digestion of swine waste. Two 50 L reactors, one with and one without zeolite amendment were operated at an OLR of 3.0 g VS L-1d-1 for 130 days, and fed with swine waste from a full-scale pig farm. Under these conditions, zeolite doses of 4 g L-1 allowed total ammonia nitrogen (TAN) concentrations to be kept below 1000 mgNH3-N L-1. The zeolite-amended reactor not only showed an average increase of 8% in methane production under stable conditions but also exhibited 34% reduction in H2S concentrations in the biogas, compared to the reactor without zeolite. The community of archaea originating from the inoculum was conserved in the reactor with zeolite amendment, particularly the acetoclastic methanogens of the genus Methanosaeta. On the other hand, in the reactor without zeolite addition, the microbial community went from being dominated by the acetoclastic methanogen Methanosaeta to having a high relative abundance of hydrogenotrophic methanogens. The zeolite addition also favoured the reactor stability, prevented foaming, and produced an enriched natural zeolite with N, P and K. However, additional studies on the potential of enriched zeolite as a fertilizer are required, which could make the use of zeolite in Anaerobic Digestion of swine waste not only energetically favourable but also economically feasible.

Effect of Operational Parameters on the Cultivation of the Gut Microbiome in Continuous Bioreactors Inoculated with Feces: A Systematic Review

Since the early 1980s, multiple researchers have contributed to the development of in vitro models of the human gastrointestinal system for the mechanistic interrogation of the gut microbiome ecology. Using a bioreactor for simulating all the features and conditions of the gastrointestinal system is a massive challenge. Some conditions, such as temperature and pH, are readily controlled, but a more challenging feature to simulate is that both may vary in different regions of the gastrointestinal tract. Promising solutions have been developed for simulating other functionalities, such as dialysis capabilities, peristaltic movements, and biofilm growth. This research field is under constant development, and further efforts are needed to drive these models closer to in vivo conditions, thereby increasing their usefulness for studying the gut microbiome impact on human health. Therefore, understanding the influence of key operational parameters is fundamental for the refinement of the current bioreactors and for guiding the development of more complex models. In this review, we performed a systematic search for operational parameters in 229 papers that used continuous bioreactors seeded with human feces. Despite the reporting of operational parameters for the various bioreactor models being variable, as a result of a lack of standardization, the impact of specific operational parameters on gut microbial ecology is discussed, highlighting the advantages and limitations of the current bioreactor systems.

Overview of the Nomenclature and Network of Contributors to the Development of Bioreactors for Human Gut Simulation Using Bibliometric Tools: A Fragmented Landscape

The evolution of complex in vitro models of the human gastrointestinal system to interrogate the biochemical functionality of the gut microbiome has augmented our understanding of its role in human physiology and pathology. With 5718 authors from 52 countries, gut bioreactor research reflects the growing awareness of our need to understand the contribution of the gut microbiome to human health. Although a large body of knowledge has been generated from in vitro models, it is scattered and defined by application-specific terminologies. To better grasp the capacity of bioreactors and further our knowledge of the human gastrointestinal system, we have conducted a cross-field bibliometric search and mapped the evolution of human gastrointestinal in vitro research. We present reference material with the aim of identifying key authors and bioreactor types to enable researchers to make decisions regarding the choice of method for simulating the human gut in the context of microbiome functionality.

Metagenomic Analysis of Biochemical Passive Reactors During Acid Mine Drainage Bioremediation Reveals Key Co-selected Metabolic Functions

Acid mine drainage (AMD) is the major pollutant generated by the mining industry, and it is characterized by low pH and high concentration of metals and sulfate. The use of biochemical passive reactors (BPRs) is a promising strategy for its bioremediation. To date, there are various studies describing the taxonomical composition of BPR microbial communities, generally consisting of an assemblage of sulfate-reducing organisms inside Deltaproteobacteria, and a diverse set of anaerobic (ligno)cellulolytic bacteria; however, insights about its functional metagenomic content are still scarce. In previous studies, a laboratory-scale AMD bioremediation using biochemical passive reactors was designed and performed, tracking operation parameters, chemical composition, and changes, together with taxonomic composition of the microbiomes harbored in these systems. In order to reveal the main functional content of these communities, we used shotgun metagenomics analyses to explore genes of higher relative frequencies and their inferred functions during the AMD bioremediation from three BPRs representing the main microbiome compositions detected in the system. Remarkably, genes encoding for two-component regulatory systems and ABC transporters related to metal and inorganic ions, cellulose degradation enzymes, dicarboxylic acid production, and sulfite reduction complex were all detected at increased frequency. Our results evidenced that higher taxonomic diversity of the microbiome was arising together with a functional redundancy of the specific metabolic roles, indicating its co-selection and suggesting that its enrichment on BPRs may be implicated in the cumulative efficiency of these systems.

Exploiting the Potential of Bioreactors for Creating Spatial Organization in the Soil Microbiome: A Strategy for Increasing Sustainable Agricultural Practices

Industrial production of synthetic nitrogen fertilizers and their crop application have caused considerable environmental impacts. Some eco-friendly alternatives try to solve them but raise some restrictions. We tested a novel method to produce a nitrogen bioinoculant by enriching a soil microbial community in bioreactors supplying N2 by air pumping. The biomass enriched with diazotrophic bacteria was diluted and applied to N-depleted and sterilized soil of tomato plants. We estimated microbial composition and diversity by 16S rRNA metabarcoding from soil and bioreactors at different run times and during plant uprooting. Bioreactors promoted the N-fixing microbial community and revealed a hided diversity. One hundred twenty-four (124) operational taxonomic units (OTUs) were assigned to bacteria with a greater Shannon diversity during the reactor’s steady state. A total of 753 OTUs were found in the rhizospheres with higher biodiversity when the lowest concentration of bacteria was applied. The apparent bacterial abundance in the batch and continuous bioreactors suggested a more specific functional ecological organization. We demonstrate the usefulness of bioreactors to evidence hidden diversity in the soil when it passes through bioreactors. By obtaining the same growth of inoculated plants and the control with chemical synthesis fertilizers, we evidence the potential of the methodology that we have called directed bioprospecting to grow a complex nitrogen-fixing microbial community. The simplicity of the reactor’s operation makes its application promising for developing countries with low technological progress.

Valorization of pulp and paper industry wastewater using sludge enriched with nitrogen-fixing bacteria

Nitrogen-fixing bacteria (NFB) can reduce nitrogen at ambient pressure and temperature. In this study, we treated effluent from a paper mill in sequencing batch reactors (SBRs) and monitored the abundance and activity of NFB with a view to producing a sludge that could work as a biofertilizer. Four reactors were inoculated with activated sludge enriched with NFB and fed with a high C/N waste (100:0.5) from a paper mill. Though the reactors were able to reduce the organic load of the wastewater by up to 89%, they did not have any nitrogen-fixing activity and showed a decrease in the putative number of NFB (quantified with qPCR). The most abundant species in the reactors treating high C/N paper mill wastewater was identified by Illumina MiSeq 16S rRNA gene amplicon sequencing as Methyloversatilis sp. (relative abundance of 4.4%). Nitrogen fixation was observed when the C/N ratio was increased by adding sucrose. We suspect that real-world biological nitrogen fixation (BNF) will only occur where there is a C/N ratio ≤100:0.07. Consequently, operators should actively avoid adding or allowing nitrogen in the waste streams if they wish to valorize their sludge and reduce running costs. PRACTITIONER POINTS: Efficient biological wastewater treatment of low nitrogen paper mill effluent was achieved without nutrient supplementation. The sludge was still capable of fixing nitrogen although this process was not observed in the wastewater treatment system. This high C/N wastewater treatment technology could be used with effluents from cassava flour, olive oil, wine and dairy industries.

High Resistance of a Sludge Enriched with Nitrogen-Fixing Bacteria to Ammonium Salts and Its Potential as a Biofertilizer

The increasing use of chemical fertilizers causes the loss of natural biological nitrogen fixation in soils, water eutrophication and emits more than 300 Mton CO₂ per year. It also limits the success of external bacterial inoculation in the soil. Nitrogen fixing bacteria can be inhibited by the presence of ammonia as its presence can inhibit biological nitrogen fixation. Two aerobic sludges from wastewater treatment plants (WWTP) were exposed to high ammonium salts concentrations (>450 mg L⁻¹ and >2 dS m⁻¹). Microbial analysis after treatment through 16S pyrosequencing showed the presence of Fluviicola sp. (17.70%), a genus of the Clostridiaceae family (11.17%), and Azospirillum sp. (10.42%), which were present at the beginning with lower abundance. Denaturing gradient gel electrophoresis (DGGE) analysis based on nifH genes did not show changes in the nitrogen-fixing population. Nitrogen-Fixing Bacteria (NFB) were identified and associated with other microorganisms involved in the nitrogen cycle, presumably for survival at extreme conditions. The potential use of aerobic sludges enriched with NFB is proposed as an alternative to chemical fertilizer as this bacteria could supplement nitrogen to the plant showing competitive results with chemical fertilization.

Resistance and induction of viable but non culturable states (VBNC) during inactivation of E. coli and Klebsiella pneumoniae by addition of H2O2 to natural well water under simulated solar irradiation

Inactivation of E. coli and Klebsiella pneumoniae by addition of H₂O₂ 10 mg L^-1 into natural well water samples containing natural total iron concentrations (around 0.3 mg L^-1) under simulated solar light was followed by bacterial culturability (plate count) and viability (DVC-FISH). Results showed that culturability of both bacteria was totally reduced while viability was only completely depleted for E. coli in well water samples depending of total iron concentration. Post-irradiation effects in presence of residual H₂O₂ showed that viability of both bacteria kept dropping being totally reduced for E. coli cells while K. pneumoniae decreased only 1-log. SEM micrographs showed that E. coli and K. pneumoniae cells underwent morphological changes and size reduction according to VBNC states. Different dark and photo-induced processes where physical-chemical features of groundwater samples play an important role could be responsible of bacteria abatement.

Enrichment of Nitrogen-Fixing Bacteria in a Nitrogen-Deficient Wastewater Treatment System

Anthropogenic nitrogen fixation is essential to sustain a global population of 7.7 billion. However, there has been a long-standing desire to find cheaper and more environmentally friendly alternatives to the Haber-Bosch process. In this study, we developed a new strategy of nitrogen fixation by enriching free-living N₂-fixing bacteria (NFB) in reactors fed with low nitrogen wastewater, analogous to those usually found in certain industrial effluents such as paper mills. Our reactors fixed appreciable quantities of nitrogen with a rate of 11.8 mg N L^-1 day^-1. This rate is comparable to recent "breakthrough" nitrogen-fixing technologies and far higher than observed in low C/N reactors (fed with organic matter and nitrogen). NFB were quantified using quantitative polymerase chain reaction (qPCR) of the nifH (marker gene used to identify biological nitrogen fixation) and 16S rRNA genes. The nifH gene was enriched by a factor of 10 in the nitrogen-fixing reactors (compared to controls) attaining 13% of the bacterial population (1:4.2 copies of nifH to 16S rRNA). The Illumina MiSeq 16S rRNA gene amplicon sequencing of reactors showed that the microbial community was dominated (19%) by Clostridium pasteurianum. We envisage that nitrogen-enriched biomass could potentially be used as a biofertilizer and that the treated wastewater could be released to the environment with very little post-treatment.

Photo-Fenton process at natural conditions of pH, iron, ions, and humic acids for degradation of diuron and amoxicillin

Effect of ferric ions at concentrations typically found in natural waters (0.05 to 1.06 mg L^-1) and low H₂O₂ concentrations (between 0.5 and 17.9 mg L^-1) on simulated sunlight-induced (300 W m^-2) photo-Fenton degradation at initial neutral pH (7.0) of amoxicillin and diuron in Milli-Q water was studied using an rotatable central composite experimental design 2² with a central and two axial points. H₂O₂ concentration was the parameter playing the key role on the degradation of both pollutants. Despite that initial pH was 7.0 in Milli-Q water, this latter decreased rapidly in the first minutes, reaching values of 3.5 and 5.0 for diuron and amoxicillin respectively after 15 min of simulated sunlight irradiation. In contrast, in presence of bicarbonate/carbonate (HCO₃^-/CO₃⁼), fluoride (F^-), and humic acids (HAs) at concentrations found often in surface and well waters with ferric ion and H₂O₂ concentrations of 0.3 and 9.7 and 15.2 mg L^-1 respectively, both pollutants exhibited a strong degradation keeping the circumneutral pH. Amoxicillin and diuron degradation byproducts found by HPLC/MS were compatible with HO^• and/or CO₃^-• radical attack. Several photo-induced processes such as photo-Fenton (by dissolved ferric-HA complexes), heterogeneous photocatalysis (by colloidal iron), UV-B H₂O₂ photolysis, irradiated-dissolved organic matter, and their reactions with pollutants would be the main oxidative route responsible of degradations. These findings demonstrated that it could be possible using iron concentrations often found in natural waters to oxidize via photo-Fenton processes among other events, organic pollutants at natural pH conditions.

A composite taxonomical and functional framework of microbiomes under acid mine drainage bioremediation systems

Mining-industry is one of the most important activities in the economic development of many countries and produces highly significant alterations on the environment, mainly due to the release of a strong acidic metal-rich wastewater called acid mine drainage (AMD). Consequently, the establishment of multiple wastewater treatment strategies remains as a fundamental challenge in AMD research. Bioremediation, as a constantly-evolving multidisciplinary endeavor had been complemented during the last decades by novel tools of increasingly higher resolution such as those based on omics approaches, which are providing detailed insights into the ecology, evolution and mechanisms of microbial communities acting in bioremediation processes. This review specifically addresses, reanalyzes and reexamines in a composite comparative manner, the available sequence information and associated metadata available in public databases about AMD impacted microbial communities; summarizing our understanding of its composition and functions, and proposing potential genetic enhancements for improved bioremediation strategies. 16 S rRNA gene-targeted sequencing data from 9 studies previously published including AMD systems reported and studied around the world, were collected and reanalyzed to compare and identify the core and most abundant genera in four distinct AMD ecosystems: surface biofilm, water, impacted soils/sediments and bioreactor microbiomes. We determined that the microbial communities of bioreactors were the most diverse in bacterial types detected. The metabolic pathways predicted strongly suggest the key role of syntrophic communities with denitrification, methanogenesis, manganese, sulfate and iron reduction. The perspectives to explore the dynamics of engineering systems by high-throughput sequencing and biochemical techniques are discussed and foreseen application of synthetic biology and omics exploration on improved AMD biotransformation are proposed.

Multiple Submucosal Out-Fracture of the Inferior Turbinates: Evaluation of the Results by Acoustic Rhinometry

A multiple submucosal out-fracture of the inferior turbinates was made in 21 patients with nasal obstruction due to hypertrophy of the inferior turbinates. Before surgery, an endoscopic evaluation and an acoustic rhinometry was performed in all the cases. The operation was done under general anesthesia and bilaterally in all the patients. Three months after surgery, a postoperative acoustic rhinometry was done and an increase of the minimal cross-section area was achieved in all the cases. Acoustic rhinometry performed in 100 normal cases was used as a control group.

2,4-D abatement from groundwater samples by photo-Fenton processes at circumneutral pH using naturally iron present. Effect of inorganic ions

This study evaluated, at laboratory scale, if the using iron naturally present (0.3 mg L^-1) and adding 10 mg L^-1 of hydrogen peroxide was effective to remove 24.3 mgL^-1 of 2,4-dichlorophenoxyacetic acid (2,4-D) from groundwater samples by simulated solar irradiation (global intensity = 300 W m^-2). Under these conditions, the degradation of 2,4-D reached 75.2 % and the apparition of its main oxidation byproduct 2,4-dichlorophenol (DCP) was observed. On the other hand, pH exhibited an increasing from 7.0 to 8.3 during the experiment. Experiments using Milli-Q water at pH 7.0, iron, and H₂O₂ concentrations of 0.3 and 10 mg L^-1, respectively, were carried out in order to study the effect of ions such as carbonate species, phosphate, and fluoride in typical concentrations often found in groundwater. Ion concentrations were combined by using a factorial experimental design 2³. Results showed that carbonates and fluoride did not produce a detrimental effect on the 2,4-D degradation, while phosphate inhibited the process. In this case, the pH increased also from 7.0 to 7.95 and 8.99. Effect of parameters such as pH, iron concentration, and hydrogen peroxide concentration on the 2,4-D degradation by the photo-Fenton process in groundwater was evaluated by using a factorial experimental design 2³. Results showed that the pH was the main parameter affecting the process. This study shows for the first time that using the photo-Fenton process at circumneutral pH and iron naturally present seems to be a promising process to remove pesticides from groundwater.

The detrimental influence of bacteria (E. coli, Shigella and Salmonella) on the degradation of organic compounds (and vice versa) in TiO2 photocatalysis and near-neutral photo-Fenton processes under simulated solar light

TiO2 photocatalytic and near-neutral photo-Fenton processes were tested under simulated solar light to degrade two models of natural organic matter - resorcinol (R) (which should interact strongly with TiO2 surfaces) and hydroquinone (H) - separately or in the presence of bacteria. Under similar oxidative conditions, inactivation of Escherichia coli, Shigella sonnei and Salmonella typhimurium was carried out in the absence and in the presence of 10 mg L(-1) of R and H. The 100% abatement of R and H by using a TiO2 photocatalytic process in the absence of bacteria was observed in 90 min for R and in 120 min for H, while in the presence of microorganisms abatement was only of 55% and 35% for R and H, respectively. Photo-Fenton reagent at pH 5.0 completely removed R and H in 40 min, whereas in the presence of microorganisms their degradation was of 60% to 80%. On the other hand, 2 h of TiO2 photocatalytic process inactivated S. typhimurium and E. coli cells in three and six orders of magnitude, respectively, while S. sonnei was completely inactivated in 10 min. In the presence of R or H, the bacterial inactivation via TiO2 photocatalysis was significantly decreased. With photo-Fenton reagent at pH 5 all the microorganisms tested were completely inactivated in 40 min of simulated solar light irradiation in the absence of organics. When R and H were present, bacterial photo-Fenton inactivation was less affected. The obtained results suggest that in both TiO2 and iron photo-assisted processes, there is competition between organic substances and bacteria simultaneously present for generated reactive oxygen species (ROS). This competition is most important in heterogeneous systems, mainly when there are strong organic-TiO2 surface interactions, as in the resorcinol case, suggesting that bacteria-TiO2 interactions could play a key role in photocatalytic cell inactivation processes.

Simultaneous E. coli inactivation and NOM degradation in river water via photo-Fenton process at natural pH in solar CPC reactor. A new way for enhancing solar disinfection of natural water

Bacteria inactivation and natural organic matter oxidation in river water was simultaneously conducted via photo-Fenton reaction at "natural" pH ( approximately 6.5) containing 0.6 mg L(-1) of Fe(3+) and 10 mg L(-1) of H(2)O(2). The experiments were carried out by using a solar compound parabolic collector on river water previously filtered by a slow sand filtration system and voluntarily spiked with Escherichia coli. Fifty five percent of 5.3 mg L(-1) of dissolved organic carbon was mineralized whereas total disinfection was observed without re-growth after 24h in the dark.

Characterization of human skeletal muscle in weight-losing pancreatic cancer patients

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Background: Decreased body mass (cachexia) is a common cause of functional decline in pancreas carcinoma (PC) and other malignancies. The etiology is unknown. Characterization of human PC skeletal muscle, in regard to proteolysis and gene expression, compared to control muscle may reveal information about pathophysiology. Methods: Biopsies of rectus abdominus muscle were performed in weight-losing PC patients all stages (A) during cancer-related surgery and in cancer-free controls undergoing ventral hernia repair (B). Caspase-3, pAkt, and urinary 3-methylhistidine (u3-MH) were assessed by Western blot and high-performance liquid chromatography. Fat-free mass (FFM), body mass index (BMI), and time to progression were recorded. Muscle from five patients (median weight loss 21%) and five controls were analyzed for gene expression patterns using Affymetrix Human Genome U133 A 2.0 array chip. Two hundred differentially over- and under-expressed genes were examined in group A for potential association with cachexia. RT-PCR confirmation of six candidate genes was performed. Results: Thirty-eight patients were enrolled. Median weight loss in group A (N=27) was 14.5% (5% - 34%). No differences were noted between groups in caspase-3 and pAkt expression. Baseline u3-MH (p=0.86) and FFM (p= 0.28) did not differ; baseline BMI was lower in group A (p=0.04). BMI follow-up measurements (N=17) were significantly decreased (p=0.0005). In 65% patients, progressive disease was noted within median time of 3 months. RT-PCR established up-regulation of CHRNA1 and LMO7, but not GDF8. mRNA down-regulation for TRIM63, IGF-BP6, and MYH-1 was confirmed. Conclusions: Muscle proteolysis in human PC skeletal muscle was not demonstrated, perhaps due to unmeasurable proteolysis or use of non-informative endpoints. BMI decreased in group A with PD; further studies need tight control of BMI variables. New hypotheses about cachexia include neuromuscular junction dysfunction, as CHRNA1 has specific role in ion channel gating; this is disrupted in the paraneoplastic Eaton-Lambert syndrome. This is first study analyzing human muscle in weight-losing PC and proves symptom management multidisciplinary research is feasible in academic setting. Supported by American Cancer Society pilot grant.

No significant financial relationships to disclose.

Development of a swine model of secondary liver tumor from a genetically induced swine fibroblast cell line

AIM

Metastatic disease is the most common liver tumor. Although alternative therapies have been developed for non-surgical candidates, those therapies lacked ideal testing prior to clinical application because of a paucity of large animal models. The purpose of the present study was to develop a model for secondary liver tumor in a large animal.

MATERIAL AND METHODS

Fibroblasts were isolated from swine ear lobules and then transfected with amphotrophic retroviruses encoding human or murine genetic material (hTERT, p53(DD), cyclinD-1, CDK4(R24C), Myc (T58A), Ras(G12V)). Transformed cell lines were finally inoculated subcutaneously (s.c.) into: 1) immunodeficient mice (nude), 2) immunocompetent mice (wild type), 3) immunosuppressed swine (under tacrolimus or corticosteroids), 4) immunocompetent swine, and 5) into the liver and portal circulation of swine under steroid-based immunosuppression.

RESULTS

In the murine model, tumor growth was evident in 100% of the nude mice (n=5), with a peak size of 20 mm (15.22+/-4.5 mm; mean+/-SD) at the time of sacrifice (3 weeks). Tumor growth was evident in 71% of the wild mice (n=21), with a peak size of 7.8 mm (4.19+/-1.1 mm) by the third week of growth. In the swine model, tumor growth was evident in 75% (3/4 ears; n=2) of swine under tacrolimus-based immunosuppression versus 50% of swine under steroids-based immunosuppression (n=2). Tumor growth was slow in two animals, while in one animal the tumor was larger with a peak growth of 42 mm at 3 weeks. The tumor pattern in the ear lobules was characterized by slow growth, with a peak size of 6-8 mm in the immunocompetent swine at 3 weeks. All tumors were shown to be malignant by histology. In contrast, inoculums of the transformed fibroblast cell line in swine livers showed no evidence of tumor growth at 3 weeks.

CONCLUSIONS

Development of a transformed swine fibroblast cell line was successful, resulting in an in vivo malignant tumor. Cell line inoculums had tumorigenic properties in nude mice, wild-type mice, and immunosuppressed swine, as judged by uncontrolled cell growth, invasion of surrounding tissue, neoangiogenesis, and invasion of normal vasculature, resulting in the formation of tumor nodules. Such properties were not observed in swine upon inoculation into the liver/portal circulation.

Feline penile erection induced by topical glans penis application of combination alprostadil and SEPA (Topiglan)

The objective of this study was to evaluate the efficacy of topically applied prostaglandin E1 (PGE(1))+5% SEPA (soft enhancement of percutaneous absorption) on the glans penis in a feline erection model. Erectile response after glans penis administration of PGE(1)+5% SEPA cream (Topiglan, MacroChem Co., Lexington, MA, USA) was compared to the erectile response after intracavernosal administration of the triple-drug combination (1.65 mg papaverine, 25 microg phentolamine, and 0.5 microg PGE(1)). The placebo cream and increasing concentrations (0.25%, 2.5 mg/ml; 0.5%, 5 mg/ml; and 1%, 10 mg/ml) of PGE(1)+5% SEPA were applied in a total volume of 0.1 ml via a plastic needle-less syringe. The control triple-drug combination was administrated intracavernosally via a 30-gauge needle at the completion of each experiment to serve as a control reference. With each application of placebo, PGE(1)+SEPA, and the triple-drug combination, changes in intracavernosal pressure and systemic blood pressure were continuously monitored. Topical application of PGE(1)+SEPA induced increases in intracavernosal pressure in a dose-dependent manner, with minimal effects on systemic blood pressure. The increases obtained with 1% PGE(1) Topiglan cream were similar to the intracavernosal pressure values elicited by the standard intracavernosal triple-drug combination. These data demonstrate that topical glans penis application of PGE(1)+SEPA can induce an erectile response in cats with minimal systemic adverse effects. Oral pharmacological agents are the first-line treatment for male ED. Studies investigating the effectiveness of noninvasive modalities such as topical therapy should continue, because these agents have the potential to avoid the systemic effects commonly seen with oral therapies. Additionally, topical therapy may also benefit patients who are unresponsive to oral agents or have explicit contraindications. Topical PGE(1) application to the glans penis may become an important treatment option in selected patients suffering from erectile dysfunction.

Mucus physiopathology, update and new therapeutic tendencies

The knowledge of mucous secretions has advanced considerably with respect to their altered physiological properties in various ear, nose and throat disorders. We review the physicochemical properties of normal mucus and abnormal mucus present in the airways during sinusitis, otitis media with effusion, etc. We have adapted the mucoactive drugs classification to the up-to-date european situation, presenting a bibliographic review. We have attempted to reconcile the agreed findings in the literature with the most recent advances in research that have resulted in new therapeutic strategies for the treatment of pathological hypersecretion in the airways.

[Lymphoma of the nasal cavity, clinical and anatomo-pathologic considerations]

Six cases of high-grade lymphoma affecting the nasal cavity are presented. Their main symptoms were nasal obstruction, epistaxis and rhinorrea. Clinical exploration showed an ulcerated lesion in four patients (all of them T/NK cell lymphomas) and an exofitic tumour in the other two (B cell lymphomas). Pathology was diagnostic for high grade lymphoma in all the six cases, immunohistochemical studies revealed that the atypical cells were T/NK in 4 cases and B in the other two cases. Genotypic analysis was done looking for rearrangement of the genes for Ig H or T-cell receptors. In situ hybridisation was done to detect Epstein-Barr virus RNA. Malignant lymphomas arising in the nasal cavity are unusual, its major prognostic factor is the clinical stage at presentation. To perform an early diagnosis this neoplasia must be suspected in the presence of an exofitic tumour (B cell lymphoma) or necrotic and ulcerated lesion (T/NK cell lymphoma).

The effect of levodopa on vocal function in Parkinson's disease

Phonatory and articulatory dysfunctions are frequent observations in Parkinson's disease. We have investigated, using acoustic measures, the effects of levodopa treatment on vocal function in 20 patients with Parkinson's disease before and after levodopa. These patients were also compared with a matched control group. The mean age was 63.5 +/- 9.66 years, Hoehn-Yahr stage was 2.38 +/- 0.45, and onset mean age was 56.5 +/- 10.36 years. Paired Wilcoxon tests were performed to compare measurements before and after levodopa. The acoustic analysis using Computerized Speech Lab and MultiDimensional Voice Program software programs (Kay Elemetrics, Lincoln Park, NJ, USA) showed that measurements of fundamental frequency (p < 0.017) were significantly increased after medication, whereas short-term frequency perturbation jitter (p < 0.033), soft phonation index (noise parameter) (p < 0.015 ), and frequency tremor intensity index (p < 0.018) were significantly decreased after medication. The objective measurements of acoustic analysis are useful in evaluating the dopaminergic pharmacologic response in Parkinson's disease. The improvement in fundamental frequency and other vocal parameters may be a result of decrease in laryngeal hypokinesia and rigidity.

[Giant ethmoid neurinoma with intracranial extension]

The schwannomas are tumors arising from nervous tissue. It appears very rarely in the nose and paranasal sinuses. Intra and extracraneal extension of these tumors are even more uncommon. In this paper we report a case of a esfeno-ethmoidal schwannoma with anterior skull fossa extension. We describe the CT scan and magnetic resonance imaging and the histological features. Surgical resection was carried through a craniofacial approach. Some data about diagnosis, treatment and outcome of these tumors are revised.

Nasal hyperreactivity to methacholine measured by acoustic rhinometry in asymptomatic allergic and perennial nonallergic rhinitis

This study was carried out to assess nasal response to different doses of methacholine and to evaluate the diagnostic possibilities of this test. Thirty-seven patients with allergic rhinitis induced by pollen (out of season), 16 with nonallergic rhinitis, and 25 normal subjects were evaluated. After provocation with saline, increasing doses of methacholine, ranging from 0.5 to 16 mg/mL, were applied. Nasal obstruction was assessed by acoustic rhinometry 10 minutes after each dose, the minimum cross-sectional area and the nasal volume in both fossae were obtained. Ipratropium bromide was applied after the last dose of methacholine to evaluate reversibility. After methacholine challenge with 0.5, 1, 2, and 4 mg/mL there was a statistically significant decrease (p < 0.05) in nasal area and volume in a dose-dependent manner in patients with allergic and nonallergic rhinitis in comparison with controls. A ROC (receiver-operating characteristic) analysis showed that a decrease in nasal volume > or = 20% at methacholine concentration of 2 mg/mL is able to predict the presence of rhinitis (positive predicted value 93%, negative predicted value 79%) in 75% of subjects. The clinical relevance of this finding suggests that patients with symptomatic nonallergic rhinitis or even asymptomatic patients with allergic rhinitis out of pollen season present a nasal hyperreactivity to methacholine, and that a decrease of nasal volume > 20% by acoustic rhinometry after challenge with methacholine at 2 mg/mL is able to discriminate these patients from normal subjects. This method seems to be a suitable tool in the diagnosis of rhinitis.

Predicting infection in localized intraabdominal fluid collections: value of pH and pO2 measurements

PURPOSE

To evaluate the use of pH, pO2, and the subjective opinion of the radiologist compared with bacterial culture in accurate diagnoses of bacterial infection in intraabdominal fluid collections.

MATERIALS AND METHODS

Prospectively, 79 patients who were suspected of having an intraabdominal fluid collection underwent diagnostic fluid aspiration. The aspirate was cultured and measured for pH and pO2. A pH < or = 7.1 and a PO2 < or = 49 mm Hg were threshold values used to separate infected from sterile fluid collections.

RESULTS

pH alone had a 92% sensitivity and 79% specificity, whereas PO2 alone had a 51% sensitivity and 79% specificity. pH or pO2 combined yielded a 92% sensitivity and 60% specificity. The radiologist's opinion produced a 83% sensitivity and 92% specificity. pH and the radiologist's opinion combined produced a 78% sensitivity and 96% specificity. pH or the radiologist's opinion combined had a 95% sensitivity and a 63% specificity.

CONCLUSION

pH is the most sensitive indicator of infection and the radiologist's opinion is the most specific. We recommend proceeding to drainage if the radiologist believes the collection to be infected and performing pH analysis if not. If the pH < or = 7.04, proceed to drainage. If neither of the above criteria are met, drainage could be delayed, pending the results of culture.

Clearance of Pneumocystis carinii cysts in acute P carinii pneumonia: assessment by serial sputum induction

STUDY OBJECTIVES

To determine the feasibility of repeat sputum induction in acute Pneumocystis carinii pneumonia (PCP) and to define the rate of clearance of P carinii cysts from the respiratory tract of HIV-seropositive patients with acute PCP.

DESIGN

Prospective cohort evaluation.

SETTING

University medical center.

PARTICIPANTS

Twenty-four HIV-seropositive subjects with acute PCP.

MEASUREMENTS

Sputum induction for P carinii 2, 3, 4, and 6 weeks after initial diagnosis, and follow-up for 1 year.

RESULTS

Eighty-eight percent of subjects had residual cysts at 2 weeks, 76% at 3 weeks, 29% at 4 weeks, and 24% at 6 weeks postdiagnosis. A prior AIDS-defining illness (p = 0.033) or prior PCP (p = 0.004) predicted relapse within 6 months, but persistent cysts at 3 weeks did not; 8 of 16 sputum-positive subjects and 1 of 5 sputum-negative subjects experienced a relapse within 6 months (p = 0.34). Secondary prophylaxis with trimethoprim-sulfamethoxazole was associated with a reduced risk of relapse.

CONCLUSIONS

Serial sputum induction coupled with direct fluorescent antibody staining is a feasible, noninvasive method of respiratory tract surveillance for the eradication of P carinii during and after acute PCP. Three-quarters of HIV-seropositive patients with acute PCP have persistent cysts in their lungs at the end of antimicrobial treatment, despite clinical recuperation, but only one quarter have residual cysts 6 weeks postdiagnosis. A prior AIDS-defining illness and prior PCP are positively associated, and subsequent trimethoprim-sulfamethoxazole prophylaxis is negatively associated, with relapse within 6 months, while persistent organisms at 3 weeks do not appear to be a significant predictor of relapse risk.

Botulinum toxin treatment for spasmodic dysphonia: percutaneous versus transoral approach

Spasmodic dysphonia (SD) is at present defined as focal dystonia. Botulinum toxin (BT) injection is the treatment of choice for SD. BT is usually injected by a percutaneous route, but a direct, visually guided transoral approach has also been successful. It is not known whether percutaneous injection is as effective as the transoral approach. This article reviews our experience with both techniques of injection on 29 patients with adductor type SD. Since 1992, we have carried out 48 treatment sessions with the transoral technique and 76 treatment sessions with the percutaneous technique. Two patients did not respond to the percutaneous technique despite several attempts, but they did respond to the transoral approach. Globally, transoral technique was superior to percutaneous technique in terms of effectiveness (48 of 48 responses with transoral technique versus 61 of 76 responses with percutaneous approach, p < 0.01). Dosage of BT, duration, and side effects were similar with both techniques. This article also describes a simple, inexpensive device, composed of materials on hand at every hospital, that facilitates the transoral approach.

[Immunohistochemistry: another criterion for typing oncocytomas of the salivary gland. A case report]

Oncocytoma of the salivary gland is uncommon and its histogenesis and pattern of evolution are debated. The criteria for malignancy are not well established. We report a morphologically benign oncocytoma of the parotid gland that was studied using various cell proliferation and tumor markers. These markers may have prognostic value and correlate with the aggressiveness of the tumor.

[Morphological changes in the respiratory tract of guinea pigs exposed to kerosene aerosol]

It's well known that there exists a high correlation between daily usage of Kerosene and the appearance of dyspnea in healthy humans and in asthmatic patients. Our aim is to study the histological alterations of the respiratory tract of guinea pigs submitted to Kerosene aerosol. It was administered to male guinea pigs fifteen minutes daily for a month. Fragments of trachea and lungs were processed for histological studies. Erosion of tracheal epithelium and inflammatory infiltration were observed. Lungs presented with thickening of the interalveolar septa. The eosinophilic infiltration may represent an immunological response resembling reactions of immediate hypersensitivity. The morphological alterations may be induced by toxic products of Kerosene such as sulphur impurities that act as mucosal irritants which damage defense mechanisms of the organism.

Tracheal ultrastructure in kerosene treated guinea pigs. A preliminary report

p6high correlation between the usage of kerosene and the appearance of asthmatic crises has been demonstrated. The ultrastructure of the upper respiratory tract of animals treated with kerosene has not been previously reported. Kerosene aerosol was administered for 15 minutes daily during 21 days to adult male guinea pigs with fragments of trachea being processed for ultrathin electron microscopical studies. Controls did not receive any treatment. Trachea of guinea pigs submitted to kerosene aerosols showed swelling, ruffling and breakdown of the ciliary membrane. The regularly arranged ciliary border was disturbed to a certain degree in some areas by the development of cytoplasmatic protrusions at the apical part of the ciliated cells. An eosinophilic infiltrate was observed deep inside the epithelium and into the lamina propria. Therefore, these ciliary alterations can be considered as one of the most important changes induced by kerosene in tracheal epithelial cells. The protrusions may represent a sign of cell alteration produced by kerosene aerosol inhalation in the guinea pig.

Prevalence of oral leukoplakia in Havana City, Cuba

A survey related to the detection of precancerous lesions of the oral cavity has been done in Cuba for the first time. The sample comprised 749 randomly selected workers from Havana City Province, taking into account the census records of the Cuban population up to 1979. Prevalence of lesions and their relation to age, sex and predisposing factors, such as smoking, alcohol habits and mechanical trauma were studied. 4.4% of leukoplakia and preleukoplakia considered together and 2.1% leukoplakia alone, and two cases of oral lichen planus and leukokeratosis nicotina palati (0.1% of each) were found. The former lesions were more frequently encountered in people above 50 years old, specially in males and specifically among those who had smoked for more than 10 years. Sites of location most frequently encountered were the buccal mucosa and the labial commissures.