Deep-learning-based, computer-aided classifier developed with a small dataset of clinical images surpasses board-certified dermatologists in skin tumour diagnosis

BACKGROUND

Application of deep-learning technology to skin cancer classification can potentially improve the sensitivity and specificity of skin cancer screening, but the number of training images required for such a system is thought to be extremely large.

OBJECTIVES

To determine whether deep-learning technology could be used to develop an efficient skin cancer classification system with a relatively small dataset of clinical images.

METHODS

A deep convolutional neural network (DCNN) was trained using a dataset of 4867 clinical images obtained from 1842 patients diagnosed with skin tumours at the University of Tsukuba Hospital from 2003 to 2016. The images consisted of 14 diagnoses, including both malignant and benign conditions. Its performance was tested against 13 board-certified dermatologists and nine dermatology trainees.

RESULTS

The overall classification accuracy of the trained DCNN was 76·5%. The DCNN achieved 96·3% sensitivity (correctly classified malignant as malignant) and 89·5% specificity (correctly classified benign as benign). Although the accuracy of malignant or benign classification by the board-certified dermatologists was statistically higher than that of the dermatology trainees (85·3% ± 3·7% and 74·4% ± 6·8%, P < 0·01), the DCNN achieved even greater accuracy, as high as 92·4% ± 2·1% (P < 0·001).

CONCLUSIONS

We have developed an efficient skin tumour classifier using a DCNN trained on a relatively small dataset. The DCNN classified images of skin tumours more accurately than board-certified dermatologists. Collectively, the current system may have capabilities for screening purposes in general medical practice, particularly because it requires only a single clinical image for classification.

164 The Origin of Oocyte, In Vitro-Matured Oocyte With/Without Super-Stimulation, and In Vivo-Matured Oocyte Influence the Timing of Cleavage in Early Embryo and Oxygen Consumption of Blastocyst After IVF in Japanese Black Cow

It has been reported that in vitro- and in vivo-matured oocyte obtained from fully growth follicles have high developmental competence. Furthermore, the timing of cleavage in early embryo after IVF affect pregnancy success after embryo transfer. It is still unknown whether origin of oocyte affects the timing of cleavage. In this study, we examined the influence of oocyte origin on cleavage timing of early embryo after IVF. Japanese Black cows were used as donors. Oocytes derived from non-stimulation follicles (control: CON), fully grown follicles after super-stimulation treatment (SST) and follicles just before ovulation after ovulation-induction treatment (in vivo-matured oocyte: VIVO) were obtained by ovum pick-up (OPU). In the CON group, OPU was conducted on arbitrary days except oestrus. In SST group, dominant follicles were aspirated and a CIDR was inserted into the vagina on Day 0, and then FSH was injected twice a day from the evening of Day 1 to the morning of Day 5 with decreasing doses in total 20 AU. In the evening of Day 4, prostaglandin F2α (0.5 mg of cloprostenol) was administered. On Day 6, SST oocytes were collected after CIDR withdrawl. In the VIVO group, the treatment was carried out as SST until prostaglandin F2α administration, and then CIDR withdrawal and administration of gonadotropin-releasing hormone (GnRH, 0.2 mg of fertirelin acetate) performed on the evening of Day 4 and morning of Day 5, respectively. The VIVO oocytes were collected at 25 to 26 h after GnRH. The CON and SST oocytes were inseminated after 20 to 22 h of IVM, and VIVO oocytes were inseminated at 30 h after GnRH, with 3 × 106 sperm mL−1, respectively. After 6 h of IVF, presumptive zygotes were individually cultured for 168 h, using a well-of-the-well dish (Dai-Nippon-Print, Japan) and were observed by time-lapse cinematography (CCM-4MZS; Astec, Japan) to analyse the cleavage timing of embryos. Oxygen consumption (O2) was measured in blastocysts on 168 hpi with a scaning electrochemical microscopy system (HV-405SP; Hokuto Denko, Japan). Statistical analysis was carried out by Steel-Dwass test for the timing of cleavage and Tukey-Kramer test for O2. In CON (n = 15), SST (n = 25), and VIVO (n = 36), the time of first cleavage was 27.5, 29.1, and 26.1 hpi, that of second cleavage was 38.9, 40.3, and 36.0 hpi, and that of third cleavage was 48.5, 46.1, and 45.9 hpi, respectively. These cleavage times were shorter in VIVO than in CON and SST (P < 0.01). The time interval between first and second cleavage (2nd cell cycle) was shorter in VIVO (10.1; P < 0.01) than CON (11.4) and SST (11.2). The time interval between second and third (3rd cell cycle) were shorter (P < 0.01) in SST (9.4) than in VIVO (10.1), and in VIVO than in CON (10.2), respectively. Consumption of O2 was lower (P < 0.01) in CON (0.61 × 10−14 mol s−1) than in SST (0.94 × 10−14 mol s−1) and VIVO (0.94 × 10−14 mol s−1). These results suggest that the origin of oocyte influences the length of cell cycle and O2 consumption of blastocyst producted in vitro.

Estimation of 134Cs activity by a new approximation referred to the sum-peak method via a well-type Ge detector

The activity of a sample containing ¹³⁴Cs and ¹³⁷Cs was estimated by means of a new approximation referred to the sum-peak method using a well-type Ge detector. The contribution of ¹³⁷Cs to the total count rate was estimated from its peak count rate, and subtracted from the total count rate. Then the total count rate originating from ¹³⁴Cs was estimated. Finally, the new method was applied and the ¹³⁴Cs activity was estimated.

Enhanced biomass production of duckweeds by inoculating a plant growth-promoting bacterium, Acinetobacter calcoaceticus P23, in sterile medium and non-sterile environmental waters

Duckweed offers the promise of a co-benefit culture combining water purification with biomass production. Acinetobacter calcoaceticus P23 is a plant growth-promoting bacterium isolated from a duckweed, Lemna aequinoctialis. This study quantified its growth-promoting effect on three duckweeds (L. aoukikusa, L. minor, and Spirodela polyrhiza) in sterile Hoagland solution and evaluated its usefulness in duckweed culture under non-sterile conditions. P23 promoted growth of three duckweeds in sterile Hoagland solution at low to high nutrient concentrations (1.25-10 mg NO₃-N/L and 0.25-2.0 mg PO₄-P/L). It increased the biomass production of L. aequinoctialis 3.8-4.3-fold, of L. minor 2.3-3.3-fold, and of S. polyrhiza 1.4-1.5-fold after 7 days compared with noninoculated controls. P23 also increased the biomass production of L. minor 2.4-fold in pond water and 1.7-fold in secondary effluent of a sewage treatment plant under non-sterile conditions at laboratory-scale experiments. P23 rescued L. minor from growth inhibition caused by microorganisms indigenous to the pond water. The results demonstrate that the use of P23 in duckweed culture can improve the efficiency of duckweed biomass production, and a positive effect of P23 on duckweed-based wastewater treatment can be assumed.

Reassessment of the clinical significance of portal-superior mesenteric vein invasion in borderline resectable pancreatic cancer

OBJECTIVE

The principal objective of this study is to clarify the prognostic significance of borderline resectable pancreatic cancer (BRPC). The second objective is to evaluate the prognostic impact of the depth of pathological venous invasion.

METHODS

The study included 122 pancreatic cancer patients who underwent curative surgery. All computed tomography scans of the patients were retrospectively interpreted and classified according to the NCCN guidelines, version 1.2016, as resectable (-) or borderline resectable (+) in each arterial (BR-A) and venous (BR-PV) involvement.

RESULTS

The overall survival (OS) rate was significantly higher in BR-A(-) patients (n = 94) than in BR-A(+) patients (n = 28) (P = 0.001), whereas there was no difference between BR-PV(-) (n = 101) and BR-PV(+) patients (n = 21) (P = 0.257). In a multivariate analysis, the independent predictors of OS included BR-A(+) (P = 0.002), lymph node metastasis (P = 0.008), pathological venous invasion (P = 0.003), and adjuvant chemotherapy (P = 0.001). Of 39 patients who underwent venous resection, no significant difference was observed between BR-PV(-) (n = 20) and BR-PV(+) patients (n = 19) in resection rate, lymph node metastasis, the presence of extrapancreatic nerve invasion, recurrence rate, frequency of initial recurrence at a liver or local site, and OS. Pathological venous invasion was significantly deeper in BR-PV(+) patients. However, the depth of invasion was not associated with OS.

CONCLUSION

The definition of venous involvement in the current guidelines predicted the depth of pathological venous invasion but not OS in BRPC patients. Further prospective, randomized studies are needed to establish treatment strategies for BRPC patients with isolated venous involvement.

Assessing the progression of chronic periodontitis using subgingival pathogen levels: a 24-month prospective multicenter cohort study

BACKGROUND

The diagnosis of the progression of periodontitis presently depends on the use of clinical symptoms (such as attachment loss) and radiographic imaging. The aim of the multicenter study described here was to evaluate the diagnostic use of the bacterial content of subgingival plaque recovered from the deepest pockets in assessing disease progression in chronic periodontitis patients.

METHODS

This study consisted of a 24-month investigation of a total of 163 patients with chronic periodontitis who received trimonthly follow-up care. Subgingival plaque from the deepest pockets was recovered and assessed for bacterial content of Porphyromonas gingivalis, Prevotella intermedia, and Aggregatibacter actinomycetemcomitans using the modified Invader PLUS assay. The corresponding serum IgG titers were measured using ELISA. Changes in clinical parameters were evaluated over the course of 24 months. The sensitivity, specificity, and prediction values were calculated and used to determine cutoff points for prediction of the progression of chronic periodontitis.

RESULTS

Of the 124 individuals who completed the 24-month monitoring phase, 62 exhibited progression of periodontitis, whereas 62 demonstrated stable disease. The P. gingivalis counts of subgingival plaque from the deepest pockets was significantly associated with the progression of periodontitis (p < 0.001, positive predictive value = 0.708).

CONCLUSIONS

The P. gingivalis counts of subgingival plaque from the deepest pockets may be associated with the progression of periodontitis.

Differential Diagnosis of Gastric Adenoma and Type IIA Early Gastric Cancer

The endoscopic and radiographic findings of 45 gastric adenomas in 39 patients were followed for 6 months to 13 years and compared with type IIa early gastric cancer observed in 9 patients. Difficulties in the differential diagnosis of these disorders were evaluated. The following features were suggestive of gastric adenomas: clustered lesions; protuberance with gentle slope; smooth surface; and relatively young patients. Discrimination of adenoma from type IIa early gastric cancer is often difficult by visual observation alone; biopsy was essential in most patients. A group III adenoma verified on biopsy should be followed closely because the lesion may harbor a cancer (so-called carcinoma-in-adenoma) or a cancer may later develop.

On the moments of a self-correcting process

The existence of ordinary and exponential moments of a point process with conditional intensity of the formis deduced from a Markov chain representation fort – ρN(t). These results form an application of recent theorems of Tweedie (1983a, b) and are used to obtain laws of large numbers for a range of functionals of the process.

Salivary pathogen and serum antibody to assess the progression of chronic periodontitis: a 24-mo prospective multicenter cohort study

BACKGROUND AND OBJECTIVE

A diagnosis of periodontitis progression is presently limited to clinical parameters such as attachment loss and radiographic imaging. The aim of this multicenter study was to monitor disease progression in patients with chronic periodontitis during a 24-mo follow-up program and to evaluate the amount of bacteria in saliva and corresponding IgG titers in serum for determining the diagnostic usefulness of each in indicating disease progression and stability.

MATERIAL AND METHODS

A total of 163 patients with chronic periodontitis who received trimonthly follow-up care were observed for 24 mo. The clinical parameters and salivary content of Porphyromonas gingivalis, Prevotella intermedia and Aggregatibacter actinomycetemcomitans were assessed using the modified Invader PLUS assay, and the corresponding serum IgG titers were measured using ELISA. The changes through 24 mo were analyzed using cut-off values calculated for each factor. One-way ANOVA or Fisher's exact test was used to perform between-group comparison for the data collected. Diagnostic values were calculated using Fisher's exact test.

RESULTS

Of the 124 individuals who completed the 24-mo monitoring phase, 62 exhibited periodontitis progression, whereas 62 demonstrated stable disease. Seven patients withdrew because of acute periodontal abscess. The ratio of P. gingivalis to total bacteria and the combination of P. gingivalis counts and IgG titers against P. gingivalis were significantly related to the progression of periodontitis. The combination of P. gingivalis ratio and P. gingivalis IgG titers was significantly associated with the progression of periodontitis (p = 0.001, sensitivity = 0.339, specificity = 0.790).

CONCLUSIONS

It is suggested that the combination of P. gingivalis ratio in saliva and serum IgG titers against P. gingivalis may be associated with the progression of periodontitis.

Evaluation of a novel immunochromatographic device for rapid and accurate clinical detection of Porphyromonas gingivalis in subgingival plaque

An important goal for the improved diagnosis and management of infectious and inflammatory diseases, such as periodontitis, is the development of rapid and accurate technologies for the decentralized detection of bacterial pathogens. The aim of this prospective multicenter study was to evaluate the clinical use of a novel immunochromatographic device with monoclonal antibodies for the rapid point-of-care detection and semi-quantification of Porphyromonas gingivalis in subgingival plaque. Sixty-three patients with chronic periodontitis and 28 periodontally healthy volunteers were subjected to clinical and microbiological examinations. Subgingival plaque samples were analyzed for the presence of P. gingivalis using a novel immunochromatography based device DK13-PG-001, designed to detect the 40k-outer membrane protein of P. gingivalis, and compared with a PCR-Invader method. In the periodontitis group, a significant strong positive correlation in detection results was found between the test device score and the PCR-Invader method (Spearman rank correlation, r=0.737, p<0.0001). The sensitivity, specificity, and positive and negative predictive values of the test device were 96.2%, 91.8%, 90.4% and 96.7%, respectively. The detection threshold of the test device was determined to be approximately 10(4) (per two paper points). There were significant differences in the bacterial counts by the PCR-Invader method among groups with different ranges of device scores. With a cut-off value of ≥0.25 in device score, none of periodontally healthy volunteers were tested positive for the subgingival presence of P. gingivalis, whereas 76% (n=48) of periodontitis subjects were tested positive. There was a significant positive correlation between device scores for P. gingivalis and periodontal parameters including probing pocket depth and clinical attachment level (r=0.317 and 0.281, respectively, p<0.01). The results suggested that the DK13-PG-001 device kit can be effectively used for rapid, chair-side detection and semi-quantification of P. gingivalis in subgingival plaque.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (UMIN-CTR) UMIN000011943.

Angiotensin (1-7) prevents angiotensin II-induced nociceptive behaviour via inhibition of p38 MAPK phosphorylation mediated through spinal Mas receptors in mice

BACKGROUND

We have recently demonstrated that intrathecal (i.t.) administration of angiotensin II (Ang II) induces nociceptive behaviour in mice accompanied by a phosphorylation of p38 mitogen-activated protein kinase (MAPK) mediated through Ang II type 1 (AT1 ) receptors. The N-terminal fragment of Ang II, Ang (1-7), plays a pivotal role in counterbalancing many of the well-established actions induced by Ang II. However, the role of Ang (1-7) in spinal nociceptive transmission remains unclear. Therefore, we examined whether i.t. administration of Ang (1-7) can inhibit the Ang II-induced nociceptive behaviour in mice.

METHODS

In the behavioural experiments, the accumulated response time of nociceptive behaviour consisting of scratching, biting and licking in conscious mice was determined during a 25-min period starting after i.t. injection. The distribution and localization of AT1 or Mas receptors were analysed using a MapAnalyzer and confocal microscope, respectively. Phosphorylation of p38 MAPK in the dorsal spinal cord was measured by Western blotting.

RESULTS

The nociceptive behaviour induced by Ang II was dose-dependently inhibited by the co-administration of Ang (1-7). The inhibitory effect of Ang (1-7) was reversed by the co-administration of A779, a Mas receptor antagonist. Western blot analysis showed that the increase in spinal p38 MAPK phosphorylation following the i.t. administration of Ang II was also inhibited by Ang (1-7), and the Ang (1-7) induced-inhibition was prevented by A779.

CONCLUSIONS

Our data show that the i.t. administration of Ang (1-7) attenuates an Ang II-induced nociceptive behaviour and is accompanied by the inhibition of p38 MAPK phosphorylation mediated through Mas receptors.

Splenic volume may be a useful indicator of the protective effect of bevacizumab against oxaliplatin-induced hepatic sinusoidal obstruction syndrome

AIMS

The aim of this study was to investigate the relationship between the use of bevacizumab (Bmab) in addition to oxaliplatin (OX), the development of sinusoidal obstruction syndrome (SOS) and the changes in splenic volume as an indicator of the protective effect of Bmab against OX-induced SOS.

METHODS

Seventy-nine patients who received OX-based chemotherapy with (OX + Bmab group: n = 48) or without Bmab (OX group: n = 31) for colorectal liver metastases were included in this study. The changes in splenic volume after chemotherapy were evaluated in the two groups. Furthermore, the relationship between the changes in splenic volume and SOS were analyzed in the 55 patients who underwent hepatectomy.

RESULTS

A significant increase in the splenic volume was observed in the OX group, but not in the OX + Bmab group. The increase in the splenic volume relative to baseline was significantly higher in the OX group than in the OX + Bmab group (39.1% vs. 2.3%, p < 0.0001). The incidence of moderate or severe SOS was significantly higher in the OX group than in the OX + Bmab group (50.0% vs. 16.0%, p = 0.0068), and the increase in the splenic volume was significantly higher in the patients with SOS than in those without SOS (42.9% vs. 9.9%, p = 0.0001). A multivariate analysis identified the increase in the splenic volume as an independent predictor of the development of SOS.

CONCLUSIONS

This study demonstrated that the inhibition of splenic volume enlargement might be a useful indicator of the protective effect of Bmab against OX-induced SOS.