Acoustic biomarkers in asthma: a systematic review

OBJECTIVE

Current monitoring methods of asthma, such as peak expiratory flow testing, have important limitations. The emergence of automated acoustic sound analysis, capturing cough, wheeze, and inhaler use, offers a promising avenue for improving asthma diagnosis and monitoring. This systematic review evaluated the validity of acoustic biomarkers in supporting the diagnosis of asthma and its monitoring.

DATA SOURCES

A search was performed using two databases (PubMed and Embase) for all relevant studies published before November 2023.

STUDY SELECTION

27 studies were included for analysis. Eligible studies focused on acoustic signals as digital biomarkers in asthma, utilizing recording devices to register or analyze sound.

RESULTS

Various respiratory acoustic signal types were analyzed, with cough and wheeze being predominant. Data collection methods included smartphones, custom sensors and digital stethoscopes. Across all studies, automated acoustic algorithms achieved average accuracy of cough and wheeze detection of 88.7% (range: 61.0 - 100.0%) with a median of 92.0%. The sensitivity of sound detection ranged from 54.0 to 100.0%, with a median of 90.3%; specificity ranged from 67.0 to 99.7%, with a median of 95.0%. Moreover, 70.4% (19/27) studies had a risk of bias identified.

CONCLUSIONS

This systematic review establishes the promising role of acoustic biomarkers, particularly cough and wheeze, in supporting the diagnosis of asthma and monitoring. The evidence suggests the potential for clinical integration of acoustic biomarkers, emphasizing the need for further validation in larger, clinically-diverse populations.

ERS International Congress 2023: highlights from the Basic and Translational Sciences Assembly

Early career members of Assembly 3 (Basic and Translational Sciences) of the European Respiratory Society (ERS) summarise the key messages discussed during six selected sessions that took place at the ERS International Congress 2023 in Milan, Italy. Aligned with the theme of the congress, the first session covered is "Micro- and macro-environments and respiratory health", which is followed by a summary of the "Scientific year in review" session. Next, recent advances in experimental methodologies and new technologies are discussed from the "Tissue modelling and remodelling" session and a summary provided of the translational science session, "What did you always want to know about omics analyses for clinical practice?", which was organised as part of the ERS Translational Science initiative's aims. The "Lost in translation: new insights into cell-to-cell crosstalk in lung disease" session highlighted how next-generation sequencing can be integrated with laboratory methods, and a final summary of studies is presented from the "From the transcriptome landscape to innovative preclinical models in lung diseases" session, which links the transcriptome landscape with innovative preclinical models. The wide range of topics covered in the selected sessions and the high quality of the research discussed demonstrate the strength of the basic and translational science being presented at the international respiratory conference organised by the ERS.

Prevalence and clinical implications of respiratory viruses in asthma during stable disease state and acute attacks: Protocol for a meta-analysis

INTRODUCTION

Viruses are detected in over 50% of acute asthma attacks and in a notable proportion of patients with asthma during stable disease state They are associated with worse outcomes. We will conduct a series of systematic reviews and meta-analyses to quantify the prevalence and clinical burden of various respiratory viruses in stable asthma and acute asthma attacks. In addition, we will assess the viral loads of respiratory viruses during stable and acute asthma, to explore whether viral load could differentiate attacks triggered by viruses versus those where viruses are present as "innocent bystanders".

MATERIALS AND METHODS

Based on a prospectively registered protocol (PROSPERO, ID: CRD42023375108) and following standard methodology recommended by Cochrane, we will systematically search Medline/PubMed, EMBASE, the Cochrane Library and relevant conference proceedings for studies assessing the prevalence or clinical burden of respiratory viruses in asthma. Methodological rigour of the included studies will be appraised using a tool specific for prevalence studies and the Newcastle-Ottawa Scale respectively. In anticipation of significant clinical and methodological heterogeneity, we will conduct random effect meta-analyses. For evaluating the prevalence of viruses, we will perform meta-analyses of proportions using the inverse variance method, and the Freeman-Tukey transformation. We will conduct meta-regression analyses for exploring heterogeneity.

CONCLUSION

We envisage that these systematic reviews and meta-analyses will quantify the prevalence and burden of respiratory viruses in stable and acute asthma and will drive future research and clinical practice.

ERS International Congress 2022: highlights from the Airway Diseases Assembly

The European Respiratory Society (ERS) celebrated the return of an in-person meeting in Barcelona, Spain, after 2 years of virtual congresses. The ERS Congress 2022 programme was replete with symposia, skills workshops and abstract presentations from all 14 assemblies, encompassing over 3000 abstracts presented in the form of thematic poster discussion and oral presentations. In this article, highlights from the ERS Congress 2022 (including from thematic poster sessions, oral presentations and symposia from keynote speakers), presented by Assembly 5 (Airway diseases, asthma, COPD and chronic cough), are reviewed by Early Career Members and experts in the field, with the aim of presenting key recent findings in the field.

ERS statement: a core outcome set for clinical trials evaluating the management of COPD exacerbations

Clinical trials evaluating the management of acute exacerbations of COPD assess heterogeneous outcomes, often omitting those that are clinically relevant or more important to patients. We have developed a core outcome set, a consensus-based minimum set of important outcomes that we recommend are evaluated in all future clinical trials on exacerbations management, to improve their quality and comparability. COPD exacerbations outcomes were identified through methodological systematic reviews and qualitative interviews with 86 patients from 11 countries globally. The most critical outcomes were prioritised for inclusion in the core outcome set through a two-round Delphi survey completed by 1063 participants (256 patients, 488 health professionals and 319 clinical academics) from 88 countries in five continents. Two global, multi-stakeholder, virtual consensus meetings were conducted to 1) finalise the core outcome set and 2) prioritise a single measurement instrument to be used for evaluating each of the prioritised outcomes. Consensus was informed by rigorous methodological systematic reviews. The views of patients with COPD were accounted for at all stages of the project. Survival, treatment success, breathlessness, quality of life, activities of daily living, the need for a higher level of care, arterial blood gases, disease progression, future exacerbations and hospital admissions, treatment safety and adherence were all included in the core outcome set. Focused methodological research was recommended to further validate and optimise some of the selected measurement instruments. The panel did not consider the prioritised set of outcomes and associated measurement instruments to be burdensome for patients and health professionals to use.

Impact of polystyrene microplastics on major marine primary (phytoplankton) and secondary producers (copepod)

The effect of microplastic adsorption on marine microalgae Tetraselmis suecica, Amphora subtropica, and copepod Pseudodiaptomus annandalei was investigated in the present study. Fluorescence microscopic images were used to evaluate MP interactions with algae and copepods. T. suecica growth rate decreased with effects of 0.1 µm polystyrene exposure to 75 µl/100 ml (0.899 to 0.601 abs), 50 µl/100 ml (0.996 to 0.632 abs) and 25 µl/100 ml (0.996 to 0.632 abs), respectively. On the other hand, at 10th day of experiment, the control T. suecica showed the highest growth rate (0.965 abs), chlorophyll concentration (Chl-'a' = 21.36 µg/L; Chl-'b' = 13.65 µg/L), and cell density (3.3 × 10⁶ cells/ml). A marine diatom A. subtropica absorbed 2.0 μm microplastics, and the maximal inhibition rate increased at higher MP concentration until 10th day. The highest MPs (75 μl/100 ml) treatment resulted in decreased growth rate of A. subtropica from 0.163 to 0.096 abs. A. subtropica (without MPs) had the highest lipid concentration of 27.15%, whereas T. suecica had the lowest lipid concentration of 11.2% (without MP). The maximum survival (80%) of P. annandalei was found in control on 15th day whereas on 12th day, the microplastics ingested copepod had the lowest survival rate (0%). On 15th day, the maximum Nauplii Production Rate (NPR) (19.33) female^-1 was observed in control, whereas the minimum (17.33) female^-1 NPR was observed in copepod ingested with MPs. The maximum lipid production (17.33% without MPs) was reported in control, whereas MPs fed copepods had the lowest lipid production (16%). Long-term exposure to polystyrene microplastics significantly reduced algae growth and chlorophyll concentration and also NPR and lipid concentration rate of copepod. We inferred that microplastic exposure of algae and copepods might results in persistent decreases in ingested carbon biomass over time.

Assessing Treatment Success or Failure as an Outcome in Randomised Clinical Trials of COPD Exacerbations. A Meta-Epidemiological Study

A recently published ERS core outcome set recommends that all trials of COPD exacerbation management should assess the treatment success (or “cure” of the exacerbation), defined as a dichotomous measure of the overall outcome of an exacerbation. This methodological systematic review describes and compares the instruments that were used to assess treatment success or failure in 54 such RCTs, published between 2006–2020. Twenty-three RCTs used composite measures consisting of several undesirable outcomes of an exacerbation, together defining an overall unfavourable outcome, to define treatment failure. Thirty-four RCTs used descriptive instruments that used qualitative or semi-quantitative descriptions to define cure, marked improvement, improvement of the exacerbation, or treatment failure. Treatment success and failure rates among patients receiving guidelines-directed treatments at different settings and timepoints are described and could be used to inform power calculations in future trials. Descriptive instruments appeared more sensitive to treatment effects compared to composite instruments. Further methodological studies are needed to optimise the evaluation of treatment success/failure. In the meantime, based on the findings of this systematic review, the ERS core outcome set recommends that cure should be defined as sufficient improvement of the signs and symptoms of the exacerbation such that no additional systemic treatments are required.

Obese, non-eosinophilic asthma: frequent exacerbators in a real-world setting

OBJECTIVE

In the UK, asthma deaths are at their highest level this century. Increased recognition of at-risk patients is needed. This study phenotyped frequent asthma exacerbators and used machine learning to predict frequent exacerbators.

METHODS

Patients admitted to a district general hospital with an asthma exacerbation between 1st March 2018 and 1st March 2020 were included. Patients were organized into two groups: "Infrequent Exacerbators" (1 admission in the previous 12 months) and "Frequent Exacerbators" (≥2 admissions in the previous 12 months). Patient data were retrospectively collected from hospital and primary care records. Machine learning models were used to predict frequent exacerbators.

RESULTS

200 patients admitted for asthma exacerbations were randomly selected (73% female; mean age 47.8 years). Peripheral eosinophilia was uncommon in either group (21% vs 19%). More frequent exacerbators were being treated with high-dose ICS than infrequent exacerbators (46.5% vs 23.2%; P < 0.001), and frequent exacerbators used more SABA inhalers (10.9 vs 7.40; P = 0.01) in the year preceding the current admission. BMI was raised in both groups (34.2 vs 30.9). Logistic regression was the most accurate machine learning model for predicting frequent exacerbators (AUC = 0.80).

CONCLUSIONS

Patients admitted for asthma are predominately female, obese and non-eosinophilic. Patients who require multiple admissions per year have poorer asthma control at baseline. Machine learning algorithms can predict frequent exacerbators using clinical data available in primary care. Instead of simply increasing the dose of corticosteroids, multidisciplinary management targeting Th2-low inflammation should be considered for these patients.

ERS Statement: A core outcome set for clinical trials evaluating the management of chronic obstructive pulmonary disease (COPD) exacerbations

Clinical trials evaluating the management of acute exacerbations of COPD assess heterogeneous outcomes, often omitting those that are clinically relevant or more important to patients. We have developed a core outcome set, a consensus-based minimum set of important outcomes that we recommend are evaluated in all future clinical trials on exacerbations management, to improve their quality and comparability. COPD exacerbations outcomes were identified through methodological systematic reviews and qualitative interviews with 86 patients from 11 countries globally. The most critical outcomes were prioritized for inclusion in the core outcome set through a two-round Delphi survey that was completed by 1,063 participants (256 patients, 488 health professionals and 319 clinical academics) from 88 countries in 5 continents. Two global, multi-stakeholder, virtual consensus meetings were conducted to (i) finalize the core outcome set and (ii) prioritize a single measurement instrument to be used for evaluating each of the prioritized outcomes. Consensus was informed by rigorous methodological systematic reviews. The views of patients with COPD were accounted for in all stages of the project. Survival, treatment success, breathlessness, quality of life, activities of daily living, need for higher level of care, arterial blood gases, disease progression, future exacerbations and hospital admissions, treatment safety and adherence were all included in the core outcome set. Focused methodological research was recommended to further validate and optimize some of the selected measurement instruments. The panel did not consider the prioritized set of outcomes and associated measurement instruments burdensome for patients and health professionals to use.

887 Suspected malignancy and unusual pathology in a severe case of Lemierre’s syndrome

Lemierre’s syndrome, although rare, is a potentially fatal condition, usually associated with the anaerobic bacterium, Fusobacterium necrophorum. This case describes a previously healthy 59-year-old female, who had a three-week history of pharyngitis and dysphagia. She presented to the emergency department with a left neck swelling and fever. A CT scan showed a 3 cm left level IV low-density suspected neck mass or necrotic node. There were multiple pulmonary nodules raising suspicion for metastases. Blood cultures were positive for Streptococcus constellatus and Dialister pneumosintes. The scan was further reviewed by a Head and Neck specialist radiologist and an Oral and Maxillofacial consultant, which highlighted a peritonsillar abscess and filling defect in the left internal jugular vein. A conclusive diagnosis of Lemierre’s syndrome with septic pulmonary emboli was established. She improved clinically with IV antibiotics in conjunction with daily enoxaparin injections. We believe that this is the first reported case of Lemierre’s syndrome associated with Dialister pneumosintes. A high index of suspicion is essential in cases of persistent pharyngitis and sepsis in an otherwise healthy individual, in order to promptly diagnose the condition and initiate treatment.

Recurrent Severe Preschool Wheeze: From Pre-Specified Diagnostic Labels to Underlying Endotypes

Rationale: Preschool wheezing is heterogeneous, but the underlying mechanisms are poorly understood.

Objectives: To investigate lower airway inflammation and infection in preschool children with different clinical diagnoses undergoing elective bronchoscopy and BAL.

Methods: We recruited 136 children aged 1–5 years (105 with recurrent severe wheeze [RSW]; 31 with nonwheezing respiratory disease [NWRD]). Children with RSW were assigned as having episodic viral wheeze (EVW) or multiple-trigger wheeze (MTW). We compared lower airway inflammation and infection in different clinical diagnoses and undertook data-driven analyses to determine clusters of pathophysiological features, and we investigated their relationships with prespecified diagnostic labels.

Measurements and Main Results: Blood eosinophil counts and percentages and allergic sensitization were significantly higher in children with RSW than in children with a NWRD. Blood neutrophil counts and percentages, BAL eosinophil and neutrophil percentages, and positive bacterial culture and virus detection rates were similar between groups. However, pathogen distribution differed significantly, with higher detection of rhinovirus in children with RSW and higher detection of Moraxella in sensitized children with RSW. Children with EVW and children with MTW did not differ in terms of blood or BAL-sample inflammation, or bacteria or virus detection. The Partition around Medoids algorithm revealed four clusters of pathophysiological features: 1) atopic (17.9%), 2) nonatopic with a low infection rate and high use of inhaled corticosteroids (31.3%), 3) nonatopic with a high infection rate (23.1%), and 4) nonatopic with a low infection rate and no use of inhaled corticosteroids (27.6%). Cluster allocation differed significantly between the RSW and NWRD groups (RSW was evenly distributed across clusters, and 60% of the NWRD group was assigned to cluster 4; P < 0.001). There was no difference in cluster membership between the EVW and MTW groups. Cluster 1 was dominated by Moraxella detection (P = 0.04), and cluster 3 was dominated by Haemophilus or Staphylococcus or Streptococcus detection (P = 0.02).

Conclusions: We identified four clusters of severe preschool wheeze, which were distinguished by using sensitization, peripheral eosinophilia, lower airway neutrophilia, and bacteriology.

Sleep apps: current limitations and challenges

Sleep app ownership is increasing exponentially, due to their accessibility and ease-of-use. However, there are several concerns regarding the use of sleep apps. Few sleep apps demonstrate empirical evidence to support their claims, and if they do, this evidence can be based on significant methodological limitations. In addition, there are data privacy concerns with regards to sleep apps, which share sensitive user data with business and marketing partners, unbeknownst to their users. Moreover, sleep apps may increase engagement with healthcare professionals, which may place additional strain on under-pressure sleep services. This would be compounded by the fact that some sleep apps produce many false positives, and clinicians would need more time to analyze the data provided by these apps. In the future, sleep apps must undergo rigorous validation studies and grant more autonomy to their users over how their data is shared.

Systematic review of thromboprophylaxis in patients having orthognathic surgery

Orthognathic surgery is an elective procedure that is done in healthy individuals so complications such as thromboembolic events are rare. Pharmacological thromboprophylaxis, which reduces the risk of these events, may also increase blood loss and potentially the risk of life-threatening haemorrhage, so a state of clinical equipoise exists about whether it should be given routinely. We systematically reviewed published papers to identify the incidence of venous thromboembolism and haemorrhage in patients treated by orthognathic surgery who were, and were not, given pharmacological thromboprophylaxis. The pooled incidence of thromboembolic events was 0% in those who were, and 0.19% in those who were not. Return to theatre to control bleeding was required in 2.72% of the patients treated at centres where it was given, and in 0.55% at those where it was not. Small sample sizes, the heterogeneity of treatment protocols, and incomplete reporting made further statistical analysis impossible. The incidence of venous thromboembolism in patients who have orthognathic surgery is low when compared with the rest of the hospital population. Although pharmacological thromboprophylaxis may further reduce this, it can also increase blood loss, and uncertainty therefore remains over the best protocol for its routine use. The risk stratification of individual patients, and large randomised controlled trials are now required to establish the best treatment.

The role of thyrostimulin and its potential clinical significance

Thyrostimulin is a glycoprotein heterodimer of GPA2 and GPB5, first described in 2002. It is involved in the physiological function of several tissues. Moreover, evidence points towards the ability of thyrostimulin's individual monomers to induce a biological effect, which could denote the circulatory/systemic effects of the molecule when found in higher concentrations. From the evolutionary point of view, thyrostimulin shares a binding epitope with the thyroid-stimulating hormone for the thyroid stimulating hormone receptor, whilst possessing affinity for another unique binding site on the same receptor. Although thyrostimulin can be involved in the hypothalamicpituitary- thyroid axis, its presence in various tissues in an eclectic array of different species renders it multifunctional. From weight loss via increasing metabolic rate to progression of cancer in human ovaries, it is certainly not a signaling molecule to overlook. Furthermore, thyrostimulin has been implicated in bone metabolism, acute illness, and reproductive function. In summary, to our knowledge, this is the first review dealing with the physiological role of thyrostimulin and its potential applications in the clinical practice.

Occupational exposure to photocopiers and their toners cause genotoxicity

Photocopier machines are inevitable office equipment, but they are also sources of air pollution. Millions of people across the world are involved in the operation and maintenance of photocopiers. We aimed to evaluate the potential genotoxic effects of exposure to photocopiers in photocopier operators and maintenance personnel by Comet assay. This study involved 50 photocopier operators, 61 maintenance personnel and 52 controls. Both the photocopier exposed groups exhibited significantly increased DNA damage when compared to controls. Cumulative exposure to photocopiers was the most significant contributor for genotoxicity ( p < 0.001). Genotoxicity among photocopier maintenance personnel may be due to the presence of carbon black, iron, silicon, magnetite and the high levels of other elements in the photocopier toners. Genotoxicity among photocopier operators might be due to exposure to high levels of particulate matter and volatile organic compounds emitted by photocopiers during operation. Research is essential to improve toner manufacturing processes and chemical composition of toners to reduce genotoxicity. Clean technologies are the need of the day to cut down on particulate matter and volatile organic compound emissions from photocopiers.

Performance of Caesalpinia sappan heartwood extract as photo sensitizer for dye sensitized solar cells

A natural dye extracted from Caesalpinia sappan heartwood was used as photo sensitizer for the first time to fabricate titanium dioxide (TiO2) nanoparticles based dye sensitized solar cells. Brazilin and brazilein are the major pigments present in the natural dye and their optimized molecular structure were calculated using Density functional theory (DFT) at 6-31G (d) level. The HOMO-LUMO were performed to reveal the energy gap using optimized structure. Pure TiO2 nanoparticles in anatase phase were synthesized by sol-gel technique. The pure and natural dye sensitized TiO2 nanoparticles were subjected to structural, optical, spectral and morphological studies. Low cost and environment friendly dye sensitized solar cells were fabricated using natural dye sensitized TiO2 based photo anode. The solar light to electron conversion efficiency of Caesalpinia sappan heartwood extract sensitized dye sensitized solar cell is 1.1%.

Natural dye extract of lawsonia inermis seed as photo sensitizer for titanium dioxide based dye sensitized solar cells

Natural dye extract of lawsonia inermis seed were used as photo sensitizer to fabricate titanium dioxide nanoparticles based dye sensitized solar cells. Pure titanium dioxide (TiO2) nanoparticles in anatase phase were synthesized by sol-gel technique and pre dye treated TiO2 nanoparticles were synthesized using modified sol-gel technique by mixing lawsone pigment rich natural dye during the synthesis itself. This pre dye treatment with natural dye has yielded colored TiO2 nanoparticles with uniform adsorption of natural dye, reduced agglomeration, less dye aggregation and improved morphology. The pure and pre dye treated TiO2 nanoparticles were subjected to structural, optical, spectral and morphological studies. Dye sensitized solar cells (DSSC) fabricated using the pre dye treated and pure TiO2 nanoparticles sensitized by natural dye extract of lawsonia inermis seed showed a promising solar light to electron conversion efficiency of 1.47% and 1% respectively. The pre dye treated TiO2 based DSSC showed an improved efficiency of 47% when compared to that of conventional DSSC.

Seasonal variations in physico-chemical characteristics of pond and ground water of Tiruchirapalli, India

The aim of this study was to assess the open pond and groundwater quality of Tiruchirapalli city of Tamil Nadu, India. The groundwater quality viz., pH, electrical conductivity, total hardness, calcium ion, magnesium ion, chloride, carbonate, bicarbonate, inorganic nitrate, nitrite, phosphate, ammonia and reactive silicate were analysed with respect to various seasons and recorded in the range of 7.1 to 8.1, 97.67 to 533.67 mhos cm(-1), 7.07 to 186 mg l(-1), 4.67 and 112.0 mg l(-1), 2.40 to 92.80 mg l(-1), 15.23 to 661.73 mg l(-1), 60 to 480 mg l(-1), 22.7 to 544.9 mg l(-1), 15.33 to 68.00 mg l(-1), 0.001 to 0.480 mg l(-1), 0.01 to 0.42 mg l(-1), 0.02 to 0.75 mg l(-1) and 1.1 to 2.96 mg l(-1) respectively. The present findings concluded that the quality of ground waters can be considered suitable for human consumption. But the pond water available in and around Tiruchirappalli city was not fit for human usage, agricultural or industrial purposes.

Copepod population in Vellar estuary, Parangipettai coast in relation to environmental conditions

Distribution and abundance of copepods were studied in relation to environmental conditions at two different ecosystems viz: Neritic (Bay of Bengal) and estuarine (Vellar estuary) of Parangipettai coast from September, 1998 toAugust, 2000. Over the study period, total 85 species of copepods were reported. Among these, the calanoid copepods constituted the major component with 63.52% followed by cyclopoids (29.41%) and harpacticoids (7.05%). The copepods population density was found to be high (2, 53,000 org l(-1)) in estuarine water, while the species diversity was higher (5.47) in neritic water. The observed spatio-temporal variations in the population density and species diversity of copepods were more related to the environmental state of respective study area.

Studies on growth, spectral, optical and mechanical properties of new organic NLO crystal: guanidinium L-glutamate (GuGL)

Good optical quality single crystal of guanidinium l-glutamate is grown by slow evaporation solution growth technique. The cell parameters and crystallinity are determined from the single crystal and powder X-ray diffraction analysis. The formation of synthesized compound was confirmed by FT-IR and FT-Raman spectroscopic analysis. Wide band gap of 4.98eV with high transmittance up to 2000 nm is observed for the grown crystal in UV-Vis-NIR spectral analysis. The optical constants such as refractive index and extinction coefficient of the grown crystal are obtained as 2.1 and 8.64×10(-6) respectively. The nonlinear optical study reveals that the second harmonic generation efficiency of guanidinium l-glutamate is 2.8 times that of potassium dihydrogen phosphate (KDP). The mechanical stability of the grown crystal was analyzed by Vickers microhardness test and the results are discussed.

Cloning and functional characterization of human SMCT2 (SLC5A12) and expression pattern of the transporter in kidney

Recently, we cloned two Na(+)-coupled lactate transporters from mouse kidney, a high-affinity transporter (SMCT1 or slc5a8) and a low-affinity transporter (SMCT2 or slc5a12). Here we report on the cloning and functional characterization of human SMCT2 (SLC5A12) and compare the immunolocalization patterns of slc5a12 and slc5a8 in mouse kidney. The human SMCT2 cDNA codes for a protein consisting of 618 amino acids. When expressed in mammalian cells or Xenopus oocytes, human SMCT2 mediates Na(+) -coupled transport of lactate, pyruvate and nicotinate. The affinities of the transporter for these substrates are lower than those reported for human SMCT1. Several non-steroidal anti-inflammatory drugs inhibit human SMCT2-mediated nicotinate transport, suggesting that NSAIDs interact with the transporter as they do with human SMCT1. Immunofluorescence microscopy of mouse kidney sections with an antibody specific for SMCT2 shows that the transporter is expressed predominantly in the cortex. Similar studies with an anti-SMCT1 antibody demonstrate that SMCT1 is also expressed mostly in the cortex. Dual-labeling of SMCT1 and SMCT2 with 4F2hc (CD98), a marker for basolateral membrane of proximal tubular cells in the S1 and S2 segments of the nephron, shows that both SMCT1 and SMCT2 are expressed in the apical membrane of the tubular cells. These studies also show that while SMCT2 is broadly expressed along the entire length of the proximal tubule (S1/S2/S3 segments), the expression of SMCT1 is mostly limited to the S3 segment. These studies suggest that the low-affinity transporter SMCT2 initiates lactate absorption in the early parts of the proximal tubule followed by the participation of the high-affinity transporter SMCT1 in the latter parts of the proximal tubule.

Implantation of oral squamous cell carcinoma at the site of a percutaneous endoscopic gastrostomy: a case report

A 55-year-old man had an operation and radiotherapy for a squamous cell carcinoma of the oral cavity and developed a metastatic deposit at the site of a percutaneous endoscopic gastrostomy, with no other evidence of systemic spread. Treatment of the metastasis was by neo-adjuvant chemotherapy with cisplatin and 5-fluorouracil (5-FU) followed by en bloc resection of the stomal recurrence on the anterior abdominal wall. There has been no evidence of recurrence to date. Only 17 other cases of metastasis to this site from a primary tumour in the upper aerodigestive tract have been reported. We review the relevant publications and discuss the techniques, complications and possible mechanisms of spread and their implications for the use of percutaneous endoscopic gastrostomy in head and neck cancer surgery.

Transforming growth factor beta1 is a target for the von Hippel-Lindau tumor suppressor and a critical growth factor for clear cell renal carcinoma

The von Hippel-Lindau (VHL) tumor suppressor gene is mutated in patients with VHL disease and in the majority of patients with sporadic clear cell renal carcinoma (RCC). Overexpression of transforming growth factor (TGF) beta1 has been observed in patients with several cancers, including RCCs, with serum and urine levels correlating inversely with prognosis. We have demonstrated that the VHL tumor suppressor gene product represses TGF-beta1 mRNA and protein levels (approximately 3-4-fold) in 786-O RCC cells by decreasing the TGF-beta1 mRNA half-life. Exogenously added TGF-beta1 did not suppress the growth of 786-O cells in vitro, nor did the addition of neutralizing antibody (Ab) against TGF-beta have any effect. Indeed, 786-O cells were found to express no TGF-beta type II receptor protein, thus allowing them to escape from the negative growth control of TGF-beta1. In contrast to the in vitro data, neutralizing Ab to TGF-beta inhibited tumorigenesis and, in some cases, regressed established 786-O tumors in athymic mice. Immunohistochemistry for von Willebrand's factor revealed a 3-4-fold lower tumor microvessel count in the mice treated with TGF-beta Ab compared to controls, suggesting that the Ab was inhibiting angiogenesis. Our findings indicate that TGF-beta1 is a novel target for the VHL tumor suppressor and that antagonizing its paracrine action may provide novel avenues for treatment of RCCs as well as other tumors that secrete TGF-beta1.

Modulation of renal tubular cell function by RGS3

The recently discovered family of regulators of G protein signaling (RGS) accelerates the intrinsic GTPase activity of certain Galpha subunits, thereby terminating G protein signaling. Particularly high mRNA levels of one family member, RGS3, are found in the adult kidney. To establish the temporal and spatial renal expression pattern of RGS3, a polyclonal antiserum was raised against the COOH terminus of RGS3. Staining of mouse renal tissue at different gestational stages revealed high levels of RGS3 within the developing and mature tubular epithelial cells. We tested whether RGS3 can modulate tubular migration, an important aspect of tubular development, in response to G protein-mediated signaling. Several mouse intermedullary collecting duct (mIMCD-3) cell lines were generated that expressed RGS3 under the control of an inducible promoter. Lysophosphatidic acid (LPA) is a potent chemoattractant that mediates its effects through heterotrimeric G proteins. We found that induction of RGS3 significantly reduced LPA-mediated cell migration in RGS3-expressing mIMCD-3 clones, whereas chemotaxis induced by hepatocyte growth factor remained unaffected by RGS3. Our findings suggest that RGS3 modulates tubular functions during renal development and in the adult kidney.

Decreased expression of the pro-apoptotic protein Par-4 in renal cell carcinoma

Par-4 is a widely expressed leucine zipper protein that confers sensitization to apoptosis induced by exogenous insults. Because the expression of genes that promote apoptosis may be down-regulated during tumorigenesis, we sought to examine the expression of Par-4 in human tumors. We present here evidence that Par-4 protein levels were severely decreased in human renal cell carcinoma specimens relative to normal tubular cells. Replenishment of Par-4 protein levels in renal cell carcinoma cell lines conferred sensitivity to apoptosis. Because apoptosis may serve as a defense mechanism against malignant transformation or progression, decreased expression of Par-4 may contribute to the pathophysiology of renal cell carcinoma.

Imaging spectroscopy for two-dimensional characterization of auroral emissions

A large throughput transmission spectrometer, with a grating on a prism as the diffraction element, has been developed to study altitude distributions of auroral emissions. The imaging spectrometer disperses spectrally in one dimension while spatial information is preserved in the orthogonal direction. The image is projected onto a CCD array detector. Image processing methods have been developed to calibrate for wavelength, uniform field, spectral sensitivity, curvature of field, and spatial mapping. Single images are processed to represent a measured signal brightness in a unit of Rayleighs/pixel, from which area integrations can be made for desired spatial-spectral resolution. System performance is ~1.5-nm resolution over a 450-nm bandwidth (420-870 nm). Two spectrometer systems of this design were operated simultaneously, one with additional optical instruments and an incoherent scatter radar at Sondrestrom, Greenland, and the other at Godhavn, Greenland, which lies 290 km to the northwest and nearly in the magnetic meridian of Sondrestrom. The developed system, calibration method, and examples of performance results are presented.

Transforming growth factor alpha is a target for the von Hippel-Lindau tumor suppressor

The von Hippel-Lindau (VHL) tumor suppressor gene has a critical role in the pathogenesis of clear cell renal cell carcinoma (RCC), because VHL mutations have been found in both VHL disease-associated and sporadic RCC. Overexpression of transforming growth factor (TGF)-alpha has been observed in numerous RCC tumors and cell lines, and TGF-alpha has been demonstrated to support RCC cell growth through an autocrine loop. We demonstrate here that VHL substantially decreases TGF-alpha message and protein by shortening TGF-alpha mRNA half-life. By Northern analysis TGF-alpha mRNA steady-state levels were suppressed 5-fold in permanent 786-0 RCC cell lines expressing wild-type VHL compared with 786-0 cells expressing an empty vector or a mutant VHL protein lacking COOH-terminal residues 116-213 (deltaVHL). By Western analysis, VHL also substantially down-regulated the unprocessed, cell-associated Mr 20,000 TGF-alpha protein. Moreover, secreted TGF-alpha was undetectable in VHL-expressing cells. In contrast, VHL did not down-regulate the TGF-alpha receptor, epidermal growth factor receptor, either at the mRNA or protein level. Nuclear run-on in vitro transcription experiments in 786-0 cells showed that VHL did not affect transcriptional control of the endogenous TGF-alpha gene. However, actinomycin D experiments revealed a long TGF-alpha mRNA half-life in 786-0 cells that was significantly decreased by wild-type VHL but not by deltaVHL. We have, therefore, identified TGF-alpha, an important growth factor for RCC, as a new target gene for VHL and demonstrated that VHL acts by decreasing TGF-alpha mRNA stability.

The von Hippel-Lindau tumor suppressor gene product interacts with Sp1 to repress vascular endothelial growth factor promoter activity

The von Hippel-Lindau tumor suppressor gene (VHL) has a critical role in the pathogenesis of clear-cell renal cell carcinoma (RCC), as VHL mutations have been found in both von Hippel-Lindau disease-associated and sporadic RCCs. Recent studies suggest that vascular endothelial growth factor (VEGF) mRNA is upregulated in RCC- and von Hippel-Lindau disease-associated tumors. We have therefore assessed the effect of the VHL gene product on VEGF expression. VEGF promoter-luciferase constructs were transiently cotransfected with a wild-type VHL (wt-VHL) vector in several cell lines, including 293 embryonic kidney and RCC cell lines. wt-VHL protein inhibited VEGF promoter activity in a dose-dependent manner up to 5- to 10-fold. Deletion analysis defined a 144-bp region of the VEGF promoter necessary for VHL repression. This VHL-responsive element is GC rich and specifically binds the transcription factor Sp1 in crude nuclear extracts. In Drosophila cells, cotransfected VHL represses Sp1-mediated activation but not basal activity of the VEGF promoter. We next demonstrated in coimmunoprecipitates that VHL and Sp1 were part of the same complex and, by using a glutathione-S-transferase-VHL fusion protein and purified Sp1, that VHL and Sp1 directly interact. Furthermore, endogenous VEGF mRNA levels were suppressed in permanent RCC cell lines expressing wt-VHL, and nuclear run-on studies indicated that VHL regulation of VEGF occurs at least partly at the transcriptional level. These observations support a new mechanism for VHL-mediated transcriptional repression via a direct inhibitory action on Sp1 and suggest that loss of Sp1 inhibition may be important in the pathogenesis of von Hippel-Lindau disease and RCC.

Inhibition of glycogenin-catalyzed glucosyl and xylosyl transfer by cytidine 5'-diphosphate and related compounds

The self-glucosylation of beef kidney glycogenin was inhibited by the following pyrimidine nucleotides and nucleotide sugars, listed in order of decreasing effectiveness: CDP-glucose, CDP, UDP-xylose, UDP-N-acetylglucosamine, UDP-galactose, UDP, CTP, CDP-choline, UDP-glucuronic acid, beta-S-UDP-glucose, and CMP. In contrast, the purine nucleotide sugars, ADP-glucose and GDP-glucose, were essentially ineffective, as was the pyrimidine nucleoside, cytidine. UDP-Xylose may be utilized by glycogenin as an alternative sugar donor instead of UDP-glucose (Rodén, L., Ananth, S., Campbell, P., Manzella, S., and Meezan, E. (1994) J. Biol. Chem. 269, 11509-11513) and therefore presumably inhibited the glucosyl transfer reaction by being a competitive substrate. Like glucosyl transfer, xylosyl incorporation into glycogenin was also inhibited effectively by CDP. On the other hand, UDP-xylose:proteoglycan core protein xylosyltransferase (EC 2.4.2.26) was not affected by CDP, nor was it inhibited by UDP-glucose. Addition of CDP or UDP-glucose to reaction mixtures containing both enzymes therefore made it possible to assay xylosyltransferase EC 2.4.2.26 reliably without the extensive product characterization that is otherwise necessary. The CDP effect on glycogenin further allowed the development of an improved procedure for the purification of this enzyme, in which specific elution of an affinity matrix (UDP-glucuronic acid-agarose) was carried out with CDP as the eluant.

Vesicular-Arbuscular Endomycorrhizal Colonization of Wetland Plants

Mycorrhizal fungi colonize many terrestrial plants and often result in an increased uptake of P and several micronutrients. Little information is available on the relationships among vesicular-arbuscular endomycorrhizae (VAM), aquatic plants, and plant P concentrations. The major objectives of this study were to measure the degree of VAM colonization of wetland plants, and to determine the relationship between colonization and plant P concentrations when sampled from two contrasting water regimes (hydric soil with no surface water and hydric soil with a minimum of 10 cm of surface water). Two semipermanent wetlands in Lake County, South Dakota, were chosen for the study. Water regime did not have a significant effect on total or organic soil P concentration. Vesicular-arbuscular endomycorrhizal spore samples collected from wet soils averaged 5000 spores kg^-1 compared with 2740 spores kg^-1 in dry soils. The eight plant species evaluated to determine VAM colonization were reed canarygrass (Phalaris arundinacea L.), slough sedge (Carex atherodes Spreng.), river bulrush [Scirpus fluviatilis (Torr.) Gray], slender rush (Juncus tenuis Willd.), dogbane (Apocynum cannabinum L.), water smartweed (Polygonum amphibium L.), cattail (Typha X glauca Godr.), and wild licorice (Glycyrrhiza lepidota (Nutt.) Pursh). Vescular-arbuscular endomycorrhizal colonization ranged from 78% (wild licorice) to none (slough sedge and slender rush). Roots from dry areas averaged 27% colonization compared with less than 1% in wet areas. Colonization levels of dogbane and reed canarygrass in dry zones were highly correlated to plant P concentrations. The results of this study indicate that several wetland plant species develop substantial mycorrhizal associations, particularly in relatively dry environments.