Performance of a deep neural network in teledermatology: a single-centre prospective diagnostic study

BACKGROUND

The use of artificial intelligence (AI) algorithms for the diagnosis of skin diseases has shown promise in experimental settings but has not been yet tested in real-life conditions.

OBJECTIVE

To assess the diagnostic performance and potential clinical utility of a 174-multiclass AI algorithm in a real-life telemedicine setting.

METHODS

Prospective, diagnostic accuracy study including consecutive patients who submitted images for teledermatology evaluation. The treating dermatologist chose a single image to upload to a web application during teleconsultation. A follow-up reader study including nine healthcare providers (3 dermatologists, 3 dermatology residents and 3 general practitioners) was performed.

RESULTS

A total of 340 cases from 281 patients met study inclusion criteria. The mean (SD) age of patients was 33.7 (17.5) years; 63% (n = 177) were female. Exposure to the AI algorithm results was considered useful in 11.8% of visits (n = 40) and the teledermatologist correctly modified the real-time diagnosis in 0.6% (n = 2) of cases. The overall top-1 accuracy of the algorithm (41.2%) was lower than that of the dermatologists (60.1%), residents (57.8%) and general practitioners (49.3%) (all comparisons P < 0.05, in the reader study). When the analysis was limited to the diagnoses on which the algorithm had been explicitly trained, the balanced top-1 accuracy of the algorithm (47.6%) was comparable to the dermatologists (49.7%) and residents (47.7%) but superior to the general practitioners (39.7%; P = 0.049). Algorithm performance was associated with patient skin type and image quality.

CONCLUSIONS

A 174-disease class AI algorithm appears to be a promising tool in the triage and evaluation of lesions with patient-taken photographs via telemedicine.

Use of the fluorescent dye tetramethylrhodamine methyl ester perchlorate for mitochondrial membrane potential assessment in human spermatozoa

Mitochondrial membrane potential (ΔΨm) is an indicator of sperm quality and its evaluation complements the standard semen analysis. The fluorescent dye JC-1 has been widely used to assess sperm ΔΨm; however, some problems have been detected under certain experimental conditions. Another fluorescent compound, tetramethylrhodamine methyl ester perchlorate (TMRM), has been used in somatic cells and bovine spermatozoa but not in human spermatozoa. TMRM accumulates in hyperpolarised mitochondria and the fluorescence intensity of this compound correlates with ΔΨm. Thus, the aim of this study was to evaluate and validate the usefulness of the fluorescent dye TMRM for measuring sperm ΔΨm. The results showed that TMRM accurately detects sperm populations displaying either high or low ΔΨm. Moreover, TMRM was able to measure sperm ΔΨm under the experimental conditions in which JC-1 had previously presented difficulties. Differences in ΔΨm according to sperm and semen quality were properly detected and a positive correlation between ΔΨm and conventional semen parameters was observed. Finally, a positive correlation was found between the ΔΨm measurement by TMRM and by the widely used JC-1. In conclusion, TMRM is a simple, time-effective method, easy to set in laboratories equipped with flow cytometry technology, and can accurately detect changes in ΔΨm with efficiency comparable to JC-1 without its limitations.

Nitrosative stress by peroxynitrite impairs ATP production in human spermatozoa

The most toxic species in live systems include reactive nitrogen species such as peroxynitrite, which at high levels induces nitrosative stress. In human spermatozoa, the negative effect of peroxynitrite on motility and mitochondrial membrane potential was recently demonstrated, and the hypothesis of this work is that impairment of ATP production could be one cause of the effect on motility. Therefore, the aim here was to evaluate ATP production by both glycolysis and oxidative phosphorylation (OXPHOS) in spermatozoa exposed to peroxynitrite in vitro. Human spermatozoa were incubated with SIN-1, a molecule which generates peroxynitrite, and the ATP level was evaluated. Then, to inactivate glycolysis or OXPHOS, spermatozoa were incubated with pharmacological inhibitors of these pathways. Spermatozoa treated for inactivating one or the other pathway were exposed to SIN-1, and the ATP level was compared to the control without SIN-1 in each condition. The ATP level fell after peroxynitrite exposure. The ATP in spermatozoa treated for inactivating one or the other metabolic pathway and subsequently exposed to peroxynitrite was reduced compared with the control. These results show for the first time that an important mechanism by which peroxynitrite reduces sperm function is the inhibition of ATP production, affecting both glycolysis and OXPHOS.

Mitochondrial outer membrane permeabilization increases reactive oxygen species production and decreases mean sperm velocity but is not associated with DNA fragmentation in human sperm

STUDY HYPOTHESIS

Does induction of mitochondrial outer membrane permeabilization (MOMP) in vitro affect specific functional parameters of human spermatozoa?

STUDY FINDING

Our findings show that MOMP induction increases intracellular reactive oxygen species (ROS) and decreases mean sperm velocity but does not alter DNA integrity.

WHAT IS KNOWN ALREADY

MOMP in somatic cells is related to a variety of apoptotic traits, such as alteration of mitochondrial membrane potential (ΔΨm), and increase in ROS production and DNA fragmentation. Although the presence of these apoptotic features has been reported in spermatozoa, to date the effects of MOMP on sperm function and DNA integrity have not been analysed.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

The study included spermatozoa from fertile donors. Motile sperm were obtained using the swim-up method. The highly motile sperm were collected and diluted with human tubal fluid to a final cell concentration of 5 × 10(6) ml(-1). To induce MOMP, selected sperm were treated at 37°C for 4 h with a mimetic of a Bcl-2 pro-apoptotic protein, ABT-737. MOMP was evaluated by relocating of cytochrome c. In addition, the effect of ABT-737 on mitochondrial inner membrane permeabilization was assessed using the calcein-AM/cobalt chloride method. In turn, ΔΨm was evaluated with JC-1 staining, intracellular ROS production with dihydroethidium, sperm motility was analysed by computer-assisted sperm analysis and DNA fragmentation by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay. Measurements were performed by flow cytometry.

MAIN RESULTS AND THE ROLE OF CHANCE

MOMP was associated with ΔΨm dissipation (P < 0.05), increased ROS production (P < 0.05) and decreased mean sperm velocity (P < 0.05), but it was not associated with DNA fragmentation. MOMP did not induce a large increase in ROS, which could explain the negligible effect of MOMP on sperm DNA fragmentation under our experimental conditions.

LIMITATIONS, REASONS FOR CAUTION

The study was carried out in vitro using highly motile sperm, selected by swim-up, from healthy donors.

WIDER IMPLICATIONS OF THE FINDINGS

The results obtained in this study reveal that the alterations of sperm functions caused by MOMP are sufficiently relevant to justify its future study in male infertility.

LARGE SCALE DATA

None.

STUDY FUNDING AND COMPETING INTERESTS

The study was funded by grant DI12-0102 from the Universidad de La Frontera (J.V.V.) and a doctoral scholarship from CONICYT (F.T.). The authors declare no conflict of interest.

Effect of mitochondrial calcium uniporter blocking on human spermatozoa

Calcium (Ca(2+) ) regulates a number of essential processes in spermatozoa. Ca(2+) is taken up by mitochondria via the mitochondrial calcium uniporter (mCU). Oxygen-bridged dinuclear ruthenium amine complex (Ru360) has been used to study mCU because it is a potent and specific inhibitor of this channel. In bovine spermatozoa, it has been demonstrated that mitochondrial calcium uptake inhibition adversely affects the capacitation process. It has been demonstrated in human spermatozoa that mCU blocking, through Ru360, prevents apoptosis; however, the contribution of the mCU to normal human sperm function has not been studied. Therefore, the aim of this study was to evaluate the effect of mCU blocking on human sperm function. Spermatozoa obtained from apparently healthy donors were incubated with 5 and 10 μm Ru360 for 4 h at 37 °C. Viability was assessed using propidium iodide staining; motility was determined by computer-aided sperm analysis, adenosine triphosphate (ATP) levels using a luminescence-based method, mitochondrial membrane potential (ΔΨm) using JC-1 staining and reactive oxygen species (ROS) production using dihydroethidium dye. Our results show that mCU blocking significantly reduced total sperm motility and ATP levels without affecting sperm viability, ΔΨm and ROS production. In conclusion, mCU contributes to the maintenance of sperm motility and ATP levels in human spermatozoa.

[Eosinophils in induced sputum versus nitric oxide in exhaled air: clinical utility in bronchial asthma]

BACKGROUND

Assessment of eosinophils in induced sputum can help to optimize anti-inflammatory therapy in bronchial asthma, but this is a very demanding technique. The aim of the study is to compare nitric oxide in exhaled air (FeNO), an easy to measure inflammatory biomarker, with eosinophils in sputum in terms of relationship with clinical and functional parameters.

METHODS

106 asthmatic patients (50 in anti-inflammatory therapy [AB+] and 56 without it [AB-]) and 15 controls were included. After filling a clinical questionnaire, FeNO measurement, forced spirometry and sputum induction by bronchial challenge with hypertonic saline solution were performed.

RESULTS

Adequate measurements of FeNO and eosinophils were obtained in 100% and 81% of the patients, respectively. FENO w were higher for AB- compared to AB+ and controls. The percentage of eosinophils in sputum was higher in asthmatic patients compared to controls but without differences between both asthmatics groups and was well correlated with the slope of the dose-response curve of bronchial challenge. In the AB- group, FeNO and eosinophils were well correlated with asthma control level.

CONCLUSION

FENO measurement is readily available and well correlated with clinical and functional markers asthma expression. Anti-inflammatory therapy blunts FeNO levels compromising its utility in the long-term follow-up of asthma patients.

Molecular Detection of Phytophthora ramorum by Real-Time Polymerase Chain Reaction Using TaqMan, SYBR Green, and Molecular Beacons

ABSTRACT Sudden oak death, caused by Phytophthora ramorum, is a severe disease that affects many species of trees and shrubs. This pathogen is spreading rapidly and quarantine measures are currently in place to prevent dissemination to areas that were previously free of the pathogen. Molecular assays that rapidly detect and identify P. ramorum frequently fail to reliably distinguish between P. ramorum and closely related species. To overcome this problem and to provide additional assays to increase confidence, internal transcribed spacer (ITS), beta-tubulin, and elicitin gene regions were sequenced and searched for polymorphisms in a collection of Phytophthora spp. Three different reporter technologies were compared: molecular beacons, TaqMan, and SYBR Green. The assays differentiated P. ramorum from the 65 species of Phytophthora tested. The assays developed were also used with DNA extracts from 48 infected and uninfected plant samples. All environmental samples from which P. ramorum was isolated by PARP-V8 were detected using all three real-time PCR assays. However, 24% of the samples yielded positive real-time PCR assays but no P. ramorum cultures, but sequence analysis of the coxI and II spacer region confirmed the presence of the pathogen in most samples. The assays based on detection of the ITS and elicitin regions using TaqMan tended to have lower cycle threshold values than those using beta-tubulin and seemed to be more sensitive.

[New techniques in the study of asthma]

Asthma is a chronic inflammatory disease of the airways that is functionally characterized by variability of lung function and bronchial hyper-responsiveness. Its diagnosis and management is commonly hampered by the lack of objective parameters. This article reviews additional techniques for evaluating both, lung function (bronchial challenge with adenosin-monophosphate, lung resistance measurement by either the impulse oscillometry system or whole body pletismography) and bronchial immuno-inflammatory response (induced sputum, condensates of exhaled air, monitoring of nitric oxide in exhaled air), as well as our experience with them.

Comparative studies of two-times-daily versus three-times-daily indinavir in combination with zidovudine and lamivudine

OBJECTIVES

To compare the efficacy and safety of two-times-daily versus three-times-daily indinavir in combination with zidovudine and lamivudine.

DESIGN

Two multicenter, open-label, randomized 24-week studies.

METHODS

Adults HIV-1 infection, HIV-1 RNA greater than 10000 copies/ml, and no prior lamivudine or protease inhibitor therapy were eligible. In a pilot study (Study A), patients received indinavir at 800 mg every 8 h, 1000 mg every 12 h, or 1200 mg every 12 h. In a subsequent study (Study B), patients received indinavir at 800 mg every 8 h or 1200 mg every 12 h. All subjects received zidovudine (300 mg) and lamivudine (150 mg) every 12 h. An intent-to-treat analysis was used.

RESULTS

In Study A, which enrolled 88 patients, neither HIV-1 RNA nor CD4 cell responses differed significantly between treatment groups at 24 weeks when corrected for multiple comparisons. Study B enrolled 433 patients, but was prematurely discontinued when interim analysis suggested greater efficacy of three-times-daily indinavir. Of the first 87 patients reaching week 24, HIV-1 RNA was less than 400 copies/ml in 91% receiving three-times-daily versus 64% receiving two-times-daily indinavir (P < 0.01).

CONCLUSION

Three-times-daily indinavir appears more efficacious than two-times-daily dosing when administered with zidovudine and lamivudine. Two-times-daily indinavir dosing should only be considered in situations characterized by favorable pharmacokinetic drug-drug interactions.

Functional cross talk after activation of P2 and P1 receptors in oviductal ciliated cells

The presence of ATP and adenosine receptors and their role in controlling ciliary activity in oviductal ciliated cells was studied by measuring the ciliary beat frequency (CBF) in oviductal tissue cultures. ATP, adenosine, and related compounds increased the CBF in a dose-dependent manner. We established that P2 receptors of subtype 2Y(2) and P1 receptors of subtype A(2a) mediated the responses to ATP and adenosine, respectively. We found evidence to suggest that stimulation of ciliary activity by ATP requires D-myo-inositol 1,4, 5-trisphosphate [Ins(1,4,5)P(3)] metabolism, intracellular Ca(2+) mobilization, and protein kinase C activation. On the other hand, the adenosine effect is mediated by activation of a G(s) protein-dependent pathway that enhances cAMP intracellular levels. To study the interaction between P2 and P1 receptors, cells were stimulated simultaneously with both agonists. We observed a synergistic increase of the CBF even at agonist concentrations (100 nM) that did not produce a significant response when added separately to the culture. Furthermore, a blocker of the cAMP pathway produced a reduction of the ATP response, whereas a blocker of the Ins(1,4,5)P(3) pathway also produced an inhibition of the adenosine response. Our evidence demonstrates that both ATP and adenosine receptors are present in a single ciliated cell and that a mechanism of cross talk could operate in the transduction pathways to control ciliary activity.

[Progression of viral infection in twins born from a mother infected with human immunodeficiency virus]

We studied the evolution of HIV-1 infection and immune response during six years in two twins born from an infected mother. The children had a continuous progression of the infection, proved by CD4+ cell count, serum anti-HIV antibodies, cultivable virus and proviral load. Now, both children are on antiviral treatment. The analysis of serum antibodies showed a different immune response in both children. One of them developed higher levels of antibodies directed against viral proteins and synthetic peptides derived from their aminoacid sequence. In this child, the amount of cultivable virus increased less than in his twin. Nucleotide sequencing of a part of viral genoma, showed that the virus belonged to the B subtype, prevalent in America and Europe. The observed differences in viral sequences suggest a different selective pressure in both twins. This phenomenon could be related to the observed differences in immune response.

Sexual behavior and status for human immunodeficiency virus type 1 among homosexual and bisexual males in Mexico City

The authors examined sexual behaviors, the seroprevalence of human immunodeficiency virus type 1 (HIV-1), and condom use among 2,314 homosexual and bisexual men tested during 1988-1989 at the AIDS (acquired immunodeficiency syndrome) National Center in Mexico City. Bisexuals constituted 24% of the sample; the seroprevalence rate was lower for bisexuals than homosexuals (21 vs. 34%). In logistic regressions, HIV-1 seropositivity was independently related to age, education, pattern of insertive/receptive behavior in anal sex, lifetime number of male sex partners, having sex with someone with AIDS, homosexual versus bisexual behavior, and a history of condyloma. The same logistic regressions were found to fit bisexuals and homosexuals. The rate of HIV-1 was reduced in individuals who indicated always requiring their partners to use a condom when practicing receptive anal sex (1% of the total). The most common practice for both homosexuals and bisexuals was "mixed" behavior (i.e., both insertive and receptive anal sex); this was also the practice with the highest risk. Bisexuals practiced both vaginal and anal sex with women and reported little condom use. The substantial seroprevalence among bisexuals, their frequent sexual contact with women, and their low rate of condom use imply a continuing role as a bridge of infection to females. Whether this risk will lead to a sustained heterosexual epidemic remains to be determined.

Reactivity patterns and infection status of serum samples with indeterminate Western immunoblot tests for antibody to human immunodeficiency virus type 1

Serum samples with indeterminate Western blot (WB) tests from 61 individuals whose sera were positive by enzyme-linked immunosorbent assay (ELISA) were studied in order to characterize their putative reactions with the human immunodeficiency virus (HIV) proteins and to resolve the HIV infection status of these individuals. The reaction observed by WB could not be confirmed either by radioimmunoprecipitation assay and subsequent electrophoresis (RIPA) or by use of LiaTek (Organon Teknika, Turnbout, The Netherlands) in 28% of the samples. Of the 86 samples that were indeterminate by WB, 66 reacted with p24 by WB; this reaction was confirmed by RIPA in only 21 (32%) and by LiaTek in 49 (74%) of the 66 samples. On the other hand, none of the indeterminate samples that reacted with HIV envelope proteins by WB did so by LiaTek, while 50% precipitated at least some of these proteins in the RIPA. The sensitivities of the three methods for detecting the antibody reaction with the different HIV proteins, which were studied with serial dilutions of positive serum samples, were similar. Thus, a lower sensitivity of RIPA or LiaTek does not seem to be the cause for the lack of reaction of the WB-indeterminate samples by these two methods. Sequential samples from individuals whose serum samples reacted by the three methods gave reproducible results, but all showed low antibody titers. Peripheral blood mononuclear cells obtained from three of the four individuals with sequential samples that reacted with HIV env proteins by WB and RIPA were negative for HIV provirus DNA after amplification by the polymerase chain reaction.

[Hospital personnel who are nasal carriers of methicillin-resistant Staphylococcus aureus. Usefulness of treatment with mupirocin]

BACKGROUND

The evaluation of health care workers role in methicillin-resistant Staphylococcus aureus outbreaks and the efficacy of mupirocin as a topical agent for nasal carriers.

METHOD

Microbiologic study of nasal microflora of 1547 health care workers from the San Carlos University Hospital and 108 health care workers from related hospitals while an outbreak of methicillin-resistant Staphylococcus aureus nosocomial infections is in progress at San Carlos University Hospital. Assessment of the efficacy of mupirocin nasal ointment for nasal carriers using microbiologic controls of nasal and pharyngeal swabs at the end of treatment and two weeks after.

RESULTS

In San Carlos University Hospital a total of 53 health care workers with nasal carriage of methicillin-resistant Staphylococcus aureus were found. That figure represents a 3.4% of all health care workers studied and also a 15.4% of methicillin-resistance among all S. aureus isolated. Among health care workers from related hospitals, only one nasal carrier was found. Forty-seven of all 53 methicillin-resistant Staphylococcus aureus isolated from San Carlos University Hospital health care workers and the strain isolated from the related hospitals health care worker were similar to the epidemic strain responsible for the outbreak. Mupirocin, as nasal ointment, was useful in eliminating nasal colonization in all cases.

CONCLUSIONS

When a nosocomial outbreak of methicillin-resistant Staphylococcus aureus infections is detected, health care workers are one of the most important reservoirs. Topical treatment with mupirocin (nasal ointment) is useful for eliminating the nasal carrier status.

Immunoprecipitation of human immunodeficiency virus type 2 glycoproteins by sera positive for human immunodeficiency virus type 1

Analysis by radioimmunoprecipitation of serum samples from 27 different human immunodeficiency virus type 1 (HIV-1)-infected individuals residing in Chile showed that the sera of 26% of these individuals also react with glycoprotein gp125 of HIV type 2 (HIV-2). This cross-reaction seems to reflect a qualitative difference among infected individuals, because the titer of antibodies against gp120 of HIV-1 in the cross-reacting samples did not differ significantly from that in the non-cross-reacting samples. Most of the HIV-1-seropositive sera, including many that did not react with gp125 of HIV-2, reacted with gp140, the precursor of HIV-2 glycoproteins. The observed cross-reactions allowed us to distinguish three groups of HIV-1-infected individuals: (i) those whose sera react with both gp140 and gp125, (ii) those whose sera react with gp140, and (iii) those whose sera react with neither of these glycoproteins. The possible cause and significance of these differences is under study.

Oxidation of Ferrous Iron and Elemental Sulfur by Thiobacillus ferrooxidans

The oxidation of ferrous iron and elemental sulfur by Thiobacillus ferrooxidans that was absorbed and unabsorbed onto the surface of sulfur prills was studied. Unadsorbed sulfur-grown cells oxidized ferrous iron at a rate that was 3 to 7 times slower than that of ferrous iron-grown cells, but sulfur-grown cells were able to reach the oxidation rate of the ferrous iron-adapted cells after only 1.5 generations in a medium containing ferrous iron. Bacteria that were adsorbed to sulfur prills oxidized ferrous iron at a rate similar to that of unadsorbed sulfur-grown bacteria. They also showed the enhancement of ferrous iron oxidation activity in the presence of ferrous iron, even though sulfur continued to be available to the bacteria in this case. An increase in the level of rusticyanin together with the enhancement of the ferrous iron oxidation rate were observed in both sulfur-adsorbed and unadsorbed cells. On the other hand, sulfur oxidation by the adsorbed bacteria was not affected by the presence of ferrous iron in the medium. When bacteria that were adsorbed to sulfur prills were grown at a higher pH (ca. 2.5) in the presence of ferrous iron, they rapidly lost both ferrous iron and sulfur oxidation capacities and became inactive, apparently because of the deposition of a jarosite-like precipitate onto the surface to which they were attached.

Bacteriology of the gallbladder bile in normal subjects

A bacteriologic analysis of the gallbladder bile in eighty patients who underwent operation was performed in a prospective study. In all twenty patients with a normal gallbladder as assessed by oral cholecystography and intraoperative palpation, cultured were negative. Among patients with chronic cholecystitis only 30 per cent had positive bile cultures and this rose to 47 per cent among patients with acute cholecystitis.

Alterations in normal esophageal motility in patients with Chagas' disease

Eight adult patients with visceral Chagas' disease were studied twice within an interval of 64 months. In each case the esophagus was evaluated radiologically and manometrically. None of the patients had esophageal symptoms and no significant change in resting gastroesophageal sphincter pressure was observed during the study. However in 3 patients incomplete sphincteric relaxation was noted. Normal progressive contractions did not change. The importance of these findings are discussed.