Accuracy of a smartphone application for triage of skin lesions based on machine learning algorithms.

BACKGROUND: Machine learning algorithms achieve expert-level accuracy in skin lesion classification based on clinical images. However, it is not yet shown whether these algorithms could have high accuracy when embedded in a smartphone app, where image quality is lower and there is high variability in image taking scenarios by users. In the past, these applications were criticized due to lack of accuracy. OBJECTIVE: In this study, we evaluate the accuracy of the newest version of a smartphone application (SA) for risk assessment of skin lesions. METHODS: This SA uses a machine learning algorithm to compute a risk rating. The algorithm is trained on 131 873 images taken by 31 449 users in multiple countries between January 2016 and August 2018 and rated for risk by dermatologists. To evaluate the sensitivity of the algorithm, we use 285 histopathologically validated skin cancer cases (including 138 malignant melanomas), from two previously published clinical studies (195 cases) and from the SA user database (90 cases). We calculate the specificity on a separate set from the SA user database containing 6000 clinically validated benign cases. RESULTS: The algorithm scored a 95.1% (95% CI, 91.9-97.3%) sensitivity in detecting (pre)malignant conditions (93% for malignant melanoma and 97% for keratinocyte carcinomas and precursors). This level of sensitivity was achieved with a 78.3% (95% CI, 77.2-79.3%) specificity. CONCLUSIONS: This SA provides a high sensitivity to detect skin cancer; however, there is still room for improvement in terms of specificity. Future studies are needed to assess the impact of this SA on the health systems and its users.

Signature of a zonally symmetric semidiurnal tide during major sudden stratospheric warmings and plausible mechanisms: a case study.

Sudden Stratospheric Warming (SSW) is a winter phenomenon initiated primarily by the enhanced stationary planetary waves (SPWs), characterized by an increase in polar stratospheric temperature by a few tens of kelvin for a few days. Wave-wave non-linear interaction can produce secondary waves, with sum and difference frequencies of the primary wave frequencies. The sun-synchronous semidiurnal tide is a major component at mid and high latitude middle atmosphere, which non-linearly interacts with the dominant SPW in the stratosphere to produce the zonally symmetric semidiurnal tide component (S0), as observed during two boreal SSWs. The zonally symmetric distribution of ozone has also potential to excite the S0 component by absorption of solar ultraviolet radiation as evident during a rare Austral SSW. Overall, the present study sheds light on the dominant generation mechanisms involved in the S0 enhancement during the SSW.

Detection of constitutive and inducible clindamycin resistance of staphlococcus in a rural tertiary care hospital.

Clindamycin has gained immense importance in the treatment of Staphylococcal infections following resistance to Beta-lactam antibiotics, especially after emergence of Methicillin Resistant Staphylococcus aureus. Clindamycin is a valuable treatment option for Staphylococcal isolates that are erythromycin resistant and clindamycin sensitive. However following exposure to erythromycin, clindamycin sensitive strains may lead to constitutive clindamycin resistance and treatment failure. But labeling all erythromycin resistant Staphylococci as clindamycin resistant strain prevents its use in infections caused by true clindamycin sensitive strains. This study aims to detect the presence of inducible clindamycin resistance among clinical isolates of Staphylococci. The detection of inducible clindamycin resistance was performed by D-Test as per the NCCLS guidelines. Among two hundred clinical isolates of Staphylococci studied, there was 24% inducible Clindamycin resistance among all the Staphylococci isolates: 29.4% among Methicillin Resistant Staphylococcus aureus and 21% among Methicillin Sensitive Staphylococcus aureus. It is advisable to include inducible clindamycin resistance testing as part of routine antimicrobial susceptibility testing.

Glutathionyl hemoglobin is elevated in iron deficiency anemia.

There are few good biomarkers of iron deficiency anemia (IDA). Since IDA patients have evidence for increased oxidative stress, we used mass spectrometry (MS) [i.e. matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization] to identify novel biomarkers. Using MALDI-MS, the following oxidative modifications of hemoglobin with the following mass-to-charge ratios were identified: 1,087.5 (α32-40), 1,545.7 (α17-31), 1,290.0 (ß31-40) and 2,076.1 (ß41-59). On electrospray ionization MS, the IDA patients had significantly elevated glutathionyl hemoglobin (GSHb) compared with the controls (16.9 ± 9.6 vs. 7.7 ± 3.7%; p = 0.002). GSHb levels correlated inversely with serum ferritin (Spearman rho -0.485; p = 0.003) and positively with serum transferrin receptor (0.460; p = 0.002). GSHb also demonstrated inverse correlations with hemoglobin (-0.512; p = 0.001), mean cell volume (-0.419; p = 0.026), serum iron (-0.446; p = 0.008) and transferrin saturation (-0.460; p = 0.008). For the first time, we show that GSHb is elevated in patients with IDA and has potential as a biomarker of this form of anemia.

Ontogeny of the digestive tract in butter catfish Ompok bimaculatus (Bloch) larvae.

The ontogeny of the digestive tract was studied histologically in butter catfish Ompok bimaculatus from hatching to 30 days post-hatching (dph). At hatching, the digestive tract of butter catfish consisted of a straight tube with a smooth lumen dorsally attached to the yolk sac. Between 1 and 2 dph, the mouth opened, oral valves were visible and canine-like teeth and taste buds were detected. During this period, intestine was differentiated into the anterior and posterior intestine, and the digestive accessory glands were also developed. Exogenous feeding started at 2 dph, and there was a 2-day mixed endogenous-exogenous feeding period. Most of the yolk sac reserves were consumed between 2 and 3 dph, and by 5 dph, the yolk sac was completely depleted and no longer visible in histological sections. Between 3 and 4 dph, several vacuoles (neutral lipids) were observed in the intestine and also in hepatocytes, indicating a functional absorption of nutrients from food. At 8 dph, differentiation of gastric glands was noticed, and by 9-11 dph, there were abundant gastric tubular glands arranged along numerous longitudinal folds. During the same period, pyloric sphincter appeared as an epithelial fold that separated the stomach from the anterior intestine. From 12 dph to the end of the study at 30 dph, no noticeable histological modifications were observed. The development of gastric glands is considered as the last major events in digestive tract development and their presence designates the end of larval period and the onset of the juvenile period. Hence, it is suggested that, butter catfish larvae have a morphologically complete digestive tract by 12 dph. These findings on the development of the digestive system in butter catfish may lead to a better understanding of the ontogeny and would be useful to improve the larval rearing techniques of this promising catfish species for freshwater aquaculture diversification.

Molecular and biochemical characterization of the human trk proto-oncogene.

Molecular analysis of the human trk oncogene, a transforming gene isolated from a colon carcinoma biopsy, revealed the existence of a novel member of the tyrosine kinase gene family. This locus, which we now designate the trk proto-oncogene, codes for a protein of 790 amino acid residues that has several features characteristic of cell surface receptors. They include (i) a 32-amino-acid-long putative signal peptide, (ii) an amino-terminal moiety (residues 33 to 407) rich in consensus sites for N-glycosylation, (iii) a transmembrane domain, (iv) a kinase catalytic region highly related to that of other tyrosine kinases, and (v) a very short (15 residue) carboxy-terminal tail. Residues 1 to 392 were absent in the trk oncogene, as they were replaced by tropomyosin sequences. However, no other differences were found between the transforming and nontransforming trk alleles (residues 392 to 790), suggesting that no additional mutations are required to activate the transforming potential of this gene. The human trk proto-oncogene codes for a 140,000-dalton glycoprotein, designated gp140proto-trk. However, its primary translational product is a 110,000-dalton glycoprotein which becomes immediately glycosylated, presumably during its translocation into the endoplasmic reticulum. This molecule, designated gp110proto-trk, is further glycosylated to yield the mature form, gp140proto-trk. Both gp110proto-trk and gp140proto-trk proteins possess in vitro kinase activity specific for tyrosine residues. Finally, iodination of intact NIH 3T3 cells expressing trk proto-oncogene products indicated that only the mature form, gp140proto-trk, cross the plasma membrane, becoming exposed to the outside of the cell. These results indicate that the product of the human trk locus is a novel tyrosine kinase cell surface receptor for an as yet unknown ligand.

Saccharomyces cerevisiae coordinates accumulation of yeast ribosomal proteins by modulating mRNA splicing, translational initiation, and protein turnover.

The rate of accumulation of each ribosomal protein is carefully regulated by the yeast cell to provide the equimolar ratio necessary for the assembly of the ribosome. The mechanisms responsible for this regulation have been examined by introducing into the yeast cell extra copies of seven individual ribosomal protein genes carried on autonomously replicating plasmids. In each case studied the plasmid-borne gene was transcribed to the same degree as the genomic gene. Nevertheless, the cell maintained a balanced accumulation of ribosomal proteins, using a variety of methods other than transcription. (i) Several ribosomal proteins were synthesized in substantial excess. However, the excess ribosomal protein was rapidly degraded. (ii) The excess mRNA for two of the ribosomal protein genes was translated inefficiently. We provide evidence that this was due to inefficient initiation of translation. (iii) The transcripts derived from two of the ribosomal protein genes were spliced inefficiently, leading to an accumulation of precursor RNA. We present a model which proposes the autogenous regulation of mRNA splicing as a eucaryotic parallel of the autogenous regulation of mRNA translation in procaryotes. Finally, the accumulation of each ribosomal protein was regulated independently. In no instance did the presence of excess copies of the gene for one ribosomal protein affect the synthesis of another ribosomal protein.

Pharmacovigilance in kala-azar patients with severe thrombocytopenia caused by sodium antimony gluconate & miltefosine.

Sodium antimony gluconate (SAG) and miltefosine used in the treatment of kala-azar are known to cause several side effects but severe thrombocytopenia has not been reported. Four cases of severe thrombocytopenia, two caused by SAG and two by miltefosine were promptly detected and treated by immediate withdrawal of the offending drugs, platelet and blood transfusions and dexamethasone. After improvement Leishman-Donovan (LD) bodies were demonstrated in splenic aspirates of both patients of SAG group and one of miltefosine and they were treated with 1 mg/kg body wt of amphotericin B for 20 days and cured. One patient of miltefosine group treated outside only on the basis of rK-39 positivity did not show LD bodies in splenic aspirates and improved without any antikala- azar drug. None of the patients relapsed within 6 months of follow up. Prompt detection of side effects under the concept of pharmacovigilance can save life of such patients.

Mutational analysis of conserved residues in the tyrosine kinase domain of the human trk oncogene.

The human trk oncogene (originally identified in a colon carcinoma) was activated by a genetic rearrangement which resulted in replacement of the extracellular ligand-binding domain of the proto-trk transmembrane receptor by non-muscle tropomyosin sequences. The product of the trk oncogene, a protein of 70 kDa (p70trk), possesses tyrosine-specific protein kinase activity, is autophosphorylated in vitro on tyrosine and is phosphorylated on serine, threonine and tyrosine residues in trk-transformed cells. By site-directed mutagenesis of trk oncogene cDNA, the codon for lysine (367) at the putative ATP-binding site was changed to that for methionine and the codons for tyrosines (503 and 504) at the putative autophosphorylation sites were changed to those for phenylalanine. Replacement of Lys-367 by methionine results in a biologically inactive, kinase-negative mutant. Phe-ala mutants of trk showed drastically reduced ability to induce morphologic transformation, anchorage-independent growth and tumorigenicity in mouse NIH3T3 cells and showed reduced in vitro tyrosine kinase activity when assayed by autophosphorylation and phosphorylation of histone as exogenous substrate. The present study indicates the role of these specific conserved residues in regulating the biochemical and biological properties of p70trk oncoprotein.

Stimulated human leukocytes cause activating mutations in the K-ras protooncogene.

Human tissues which are chronically infiltrated with inflammatory leukocytes are more likely to develop malignancies than non-inflamed tissues, however the mechanism(s) by which leukocytes contribute to carcinogenesis is unknown. Stimulated human leukocytes release superoxide anion and hydrogen peroxide which, in the presence of iron, can be converted into the potent oxidant, hydroxyl radical (.OH). Previous studies have shown that leukocyte-derived .OH (or a .OH-like species) can cause DNA damage, however a relationship between leukocyte-induced DNA damage and carcinogenesis has not been established. The present report demonstrates that leukocyte-derived .OH-induced DNA damage can cause K-ras oncogene activation, and suggests that there may be a characteristic pattern of .OH-induced K-ras oncogene activation. Since activation of the K-ras oncogene is believed to play a crucial role in the pathogenesis of many human malignancies, .OH-induced K-ras oncogene activation could be an important mechanism by which human leukocytes contribute to carcinogenesis.

Detection and reduction of protein A contamination in immobilized protein A purified monoclonal antibody preparations.

Protein A chromatography is an excellent technique for the purification of monoclonal antibodies. However, the presence of Protein A in therapeutic monoclonal antibody preparations due to leaching has been linked with toxicity in animals and humans. Two sandwich ELISAs were developed to monitor Protein A column leaching: (1) rabbit anti-Protein A for capture and anti-Protein A F(ab')2-HRP for detection; and (2) rabbit anti-Protein A for capture and anti-Protein A-biotin for detection. The biotin ELISA is sensitive to the subnanogram range. In addition, these assays were used to develop DEAE and gel filtration chromatography techniques that substantially reduce Protein A levels in monoclonal antibodies purified by Protein A chromatography.

Monoclonal anti-tumor necrosis factor (TNF) antibodies protect mouse and human cells from TNF cytotoxicity.

Tumor necrosis factor (TNF) is a cytokine produced by macrophages which mediates septic shock. TNF is also associated with anti-tumor activity and is cytotoxic to many cell lines in vitro. While the clinical efficacy of anti-TNF antibodies has yet to be established, such antibodies may prevent TNF action. We have evaluated three murine monoclonal anti-TNF antibodies for their capacity to protect mouse and human cells from the cytotoxic effects of human TNF. Mouse WEHI 164 cells were tested because of their known high sensitivity to TNF. Several human cells lines were also examined: U937, HeLa, MRC5, and ME180. Two antibodies protected mouse and human cells from the cytotoxic action of TNF. The neutralizing activity was also present in the Fab fragment and insensitive to the presence of carbohydrate on the antibody. The third antibody had substantially less TNF-neutralizing activity. The relative ability of these monoclonal antibodies to protect both mouse and human cell lines from TNF-induced cell death may be an effective indicator of their in vivo efficacy.

Inactivation of viruses in therapeutic products derived from human plasma.

Alpha-1-proteinase inhibitor concentrates have been prepared from pooled human plasma for therapeutic applications. Pasteurization (60 degrees C, 10 hours) conditions have been defined to reduce risks of transmission of viral agents without significant loss of biologic activity of the purified product. Human clinical data collected to date support the model virus inactivation studies regarding viral safety.

Monoclonal antibody binding to factor VIII:c.

The interactions of human blood clotting Factor VIII:c with 2 monoclonal antibodies, C7F7 and BD10, were examined with an enzyme-linked immunosorbent assay (ELISA) method. A Scatchard-Sips plot approach to data analysis was used to calculate an average affinity (Ko), valence (n), and heterogeneity index (a) for each interaction. Using a Factor VIII:c coating ELISA method, the following constants were determined: BD10: Ko = 5.48 X 10(8) M-1; n = 0.31; a = 0.97; C7F7: Ko = 2.3 X 10(11) M-1; n = 0.018; a = 0.77.

Hepatitis B virus associated DNA polymerase inactivation in factor IX concentrates.

Inactivation of Hepatitis B virus associated DNA polymerase was studied in factor IX concentrate (coagulation factors II, VII, IX and X) by heat pasteurization (60 degrees C, 10 hr) and by alkylating agents iodoacetic acid and iodoacetamide. DNA polymerase appeared to reach a residual level which occurred in human serum albumin at 60 degrees C, 10 hr under comparable spike level of hepatitis B virus. Of the four coagulation factors, factor IX activity was most susceptible to inactivation procedures with 40-50% recovery across heat pasteurization and approximately 70% recovery across iodoacetic acid treatment. Factor IX specific activities of the treated concentrates were greater than or equal to 70% of the untreated controls with no appreciable change of corresponding NAPTT values. Factor IX concentrates subjected to such inactivation procedures should reduce the potential for hepatitis B virus transmission.

Preparation of high purity factor VIII concentrates.

An improved process for producing high purity Factor VIII concentrate has been developed. The improvement was based on the combination of three precipitating agents (polyethylene glycol, glycine and sodium chloride) which heretofore have been used alone in a single step or in separate and distinct steps in a multi-step process. The product was pasteurized in solution (60 degrees C, 10 hrs) to reduce possible risks of virus transmission. The purified product has significantly higher specific activity and lower fibrinogen and immunoglobulin levels when compared to other commercial concentrates.

Removal of DNA contaminants from therapeutic protein preparations.

Mammalian cell culture-derived biotechnical products for therapeutic use have risks associated with cell substrate DNA. Regulatory authorities in the USA and Europe have set stringent limits for this contaminant, requiring orders of magnitude reduction from fermenter harvests to purified products. This paper addresses the relevant unit processes (e.g., cell separation, affinity chromatography and ion-exchange chromatography) utilized for purification of mammalian cell culture-derived products as they pertain to removal of DNA contaminants.

A synthesis of 7alpha-hydroxyandrost-4-ene-3,17-dione.

The first convenient chemical synthesis of 7alpha-hydroxyandrost-4-ene-3,17-dione is reported. Androsta-4,6-diene3, 17-dione was converted into its 6alpha, 7alpha-epoxy-derivative; reduction of the epoxide with aluminum amalgam gave 7alpha-hydroxyandrost-4-ene-3,17-dione. This reducing agent is more efficient than chromous acetate for the purpose.

Enhanced 3D PET OSEM reconstruction using inter-update Metz filtering.

We present an enhancement of the OSEM (ordered set expectation maximization) algorithm for 3D PET reconstruction, which we call the inter-update Metz filtered OSEM (IMF-OSEM). The IMF-OSEM algorithm incorporates filtering action into the image updating process in order to improve the quality of the reconstruction. With this technique, the multiplicative correction image--ordinarily used to update image estimates in plain OSEM--is applied to a Metz-filtered version of the image estimate at certain intervals. In addition, we present a software implementation that employs several high-speed features to accelerate reconstruction. These features include, firstly, forward and back projection functions which make full use of symmetry as well as a fast incremental computation technique. Secondly, the software has the capability of running in parallel mode on several processors. The parallelization approach employed yields a significant speed-up, which is nearly independent of the amount of data. Together, these features lead to reasonable reconstruction times even when using large image arrays and non-axially compressed projection data. The performance of IMF-OSEM was tested on phantom data acquired on the GE Advance scanner. Our results demonstrate that an appropriate choice of Metz filter parameters can improve the contrast-noise balance of certain regions of interest relative to both plain and post-filtered OSEM, and to the GE commercial reprojection algorithm software.