A Wearable Cellulose Acetate-Coated Mouthguard Biosensor for In Vivo Salivary Glucose Measurement.

In this study, a cellulose acetate (CA) membrane is formed as an interference rejection membrane on a glucose sensor to measure glucose in saliva. Glucose in saliva is successfully measured in vivo without any pretreatment of human saliva. A mouthguard (MG) glucose sensor is developed to monitor salivary glucose, which is reported to be correlated with the blood glucose level. Salivary components of ascorbic acid (AA) and uric acid (UA) hinder the accurate measurement of the glucose concentration of human saliva. CA-coated electrodes are prepared to investigate the interference rejection membrane. To measure hydrogen peroxide, which is a reaction product of glucose oxidase, effects of AA and UA are examined. Characteristics of the fabricated biosensor are examined on the basis of artificial saliva. The as-developed MG sensor can quantify the glucose concentration in the range of 1.75-10 000 µmol/L, which includes a salivary sugar concentration of 20-200 µmol/L. For the measurement of saliva samples collected from healthy subjects, the output corresponding to the concentration is confirmed; this suggests the possibility of glucose measurement. This MG glucose sensor can provide a useful method for the unrestricted and noninvasive monitoring of saliva glucose for the management of diabetes patients.

Young gastric cancer patient with high CA19-9 complicated by Trousseau syndrome.

A 47-year-old Japanese woman presented with epigastric discomfort and anorexia. Upper endoscopy showed type 4 advanced gastric cancer in the gastric antrum with stenosis of the pyloric portion. Abdominopelvic CT revealed peritoneal dissemination, and stage IV advanced gastric cancer was diagnosed. Laparoscopic gastrojejunostomy and enterostomy were performed. Trousseau syndrome occurred 7 days post-surgery. Despite appropriate treatment, the patient developed a pulmonary embolism 13 days later and died 18 days post-surgery. Even in young cancer patients without lifestyle disease complications, it is important to pay attention to Trousseau syndrome as part of cancer management.

A case of early autoimmune gastritis with characteristic endoscopic findings.

Significant atrophic gastritis in the fundic gland region is a well-known endoscopic finding observed in autoimmune gastritis (AIG). The endoscopic features of early AIG have not been reported. Iron deficiency, vitamin B12 deficiency, anemia, or neurological symptoms may not be observed in the early stages of AIG, and it may thus be difficult to diagnose early AIG based on clinical findings. We treated a 50-year-old Japanese female whose condition was suspected to be early AIG. The endoscopic findings showed normal gastric pyloric gland mucosa, and diffuse reddened and edematous gastric fundic gland mucosa. Pathologically, local infiltration of lymphocytes and decrease of parietal cells was present in a deep part of the gastric fundic gland mucosa. Blood tests showed that the titer of parietal cell antibody (PCA) was 1:320 and the gastrin level was 820 pg/ml. We determined that the patient had AIG because she also had Hashimoto's disease, the PCA titer was high, the serum gastrin level was slightly increased, and inflammation was observed only in the gastric body on the endoscopic images. To the best of our knowledge, this is the first case report of endoscopic findings that suggest early AIG, before atrophic changes were observed.

Two cases of accidental ingestion of a press-through package (PTP) sheet, diagnosed by tomosynthesis prior to endoscopy.

The accidental ingestion of a press-through package (PTP) sheet is associated with the risk of gastrointestinal injury and puncture. When pain occurs in the laryngeal pharynx, the PTP may already be stuck in the upper esophageal region, and urgent endoscopic treatment is necessary. A plain chest X-ray image should be performed first to identify the ingested PTP, but this was not successful in the present two patients. As a next step, a CT scan (which involves high radiation exposure) is commonly used. In our patients (a 76-year-old woman and a 59-year-old man), tomosynthesis was used to confirm the presence and location of a PTP sheet as a pre-endoscopic diagnosis. With tomosynthesis, the level of radiation exposure was reduced to approx. 1/10 of that of simple CT; the imaging time is also shorter at ~ 5 s. Tomosynthesis can be performed at approx. 1/3-1/4 the cost of simple CT. The usefulness of tomosynthesis as a pre-endoscopic diagnostic tool was demonstrated in our patients, and its further utilization is expected.

Mouthguard biosensor with telemetry system for monitoring of saliva glucose: A novel cavitas sensor.

We develop detachable "Cavitas sensors" to apply to the human oral cavity for non-invasive monitoring of saliva glucose. A salivary biosensor incorporating Pt and Ag/AgCl electrodes on a mouthguard support with an enzyme membrane is developed and tested. Electrodes are formed on the polyethylene terephthalate glycol (PETG) surface of the mouthguard. The Pt working electrode is coated with a glucose oxidase (GOD) membrane. The biosensor seamlessly is integrated with a glucose sensor and a wireless measurement system. When investigating in-vitro performance, the biosensor exhibits a robust relationship between output current and glucose concentration. In artificial saliva composed of salts and proteins, the glucose sensor is capable of highly sensitive detection over a range of 5-1000µmol/L of glucose, which encompasses the range of glucose concentrations found in human saliva. We demonstrate the ability of the sensor and wireless communication module to monitor saliva glucose in a phantom jaw imitating the structure of the human oral cavity. Stable and long-term real-time monitoring (exceeding 5h) with the telemetry system is achieved. The mouthguard biosensor will be useful as a novel method for real-time non-invasive saliva glucose monitoring for better management of dental patients.