Particle Size Analysis in Aerosol-Generating Dental Procedures Using Laser Diffraction Technique.

The global outbreak of coronavirus disease 2019 (COVID-19) has raised concerns about the risk of airborne infection during dental treatment. Aerosol-generating dental procedures (AGDP) produce droplets and aerosols, but the details of the risks of COVID-19 transmission in AGDP are not well-understood. By discriminating between droplets and aerosols, we devised a method to measure particle size using laser diffraction analysis and evaluated aerosols generated from dental devices for providing a basis for proper infection control procedures. The droplets and aerosols generated from dental devices were characterized by multimodal properties and a wide range of droplet sizes, with the majority of droplets larger than 50 µm. AGDP emitted few aerosols smaller than 5 µm, which are of concern for pulmonary infections due to airborne transmission. In addition, the use of extraoral suction was found to prevent the spread of aerosols from high-speed dental engines. This study suggests that the risk of aerosol infections is considerably limited in regular dental practice and that current standard precautions, such as mainly focusing on protection against droplet and contact infections, are sufficient. While several cases of airborne transmission of COVID-19 in general clinics and emergency hospitals have been reported, cluster outbreaks in dental clinics have not yet been reported, which may indicate that AGDP does not pose a significant threat in contributing to the spread of SARS-CoV-2.

Long-term remission of primary gastric T cell lymphoma associated with human T lymphotropic virus type 1: a report of two cases and review of the literature.

Two cases of primary gastric T-cell lymphoma associated with human T lymphotropic virus type 1 (HTLV-1) are presented. Case 1 was a 54-year-old man who had multiple ulcerating tumors in the lower corpus and gastric antrum. Case 2, a 60-year-old man, showed a large ulcerating tumor in the upper corpus. Both patients were positive for serum anti-HTLV-1 antibody and for the monoclonal integration of HTLV-1 proviral DNA in the tumor cells by Southern blot analysis. The patients were thus diagnosed as having primary gastric T-cell lymphoma associated with HTLV-1 of stage II(1). Case 1 underwent total gastrectomy followed by chemotherapy, while Case 2 was treated by chemotherapy and radiotherapy. Both patients have been in complete remission for more than 4 years (96 months in Case 1 and 50 months in Case 2) after the treatments. Although primary gastric T-cell lymphomas associated with HTLV-1 is characterized by an extremely poor prognosis, the present cases suggest that in the early stage, long-term survival can possibly be achieved with appropriate treatments.

Nodular glomerulosclerosis in patients without any manifestation of diabetes mellitus.

AIM/METHODS: Diabetic nodular glomerulosclerosis is considered to be the specific renal lesion of diabetes mellitus (DM). However, some cases, in which nodular glomerulosclerosis was found without any manifestation of DM, have also occasionally been reported. We clinicopathologically examined seven cases without a prior history of DM. They consisted of six men and one woman with a mean age of 57 years, and included three cases with family history of DM and six cases with hypertension. RESULTS: Mean body mass index was 26.2 +/- 5.9 (means +/- SD) kg/m(2) and haemoglobin A1c 5.3 +/- 1.1% or haemoglobin A1 7.0 +/- 0.6%. Mean plasma glucose levels were 5.3 +/- 0.7 mmol/L at fasting and 10.1 +/- 1.9 mmol/L at 2 h of 75 g OGTT (normal: 1 patient; impaired glucose tolerance: 4 patients; DM: 2 patients). None of them showed diabetic retinopathy in fundoscopic ophthalmoscopy. Mean serum creatinine was 268 +/- 215 micromol/L, urinary protein 5.2 +/- 4.0 g/day, and three patients had mild haematuria. Renal biopsy revealed typical nodular glomerulosclerosis, a negative deposition based on an immunofluorescence study, and neither any significant electron dense deposits nor fibrils on electron microscopy. CONCLUSION: These patients at presentation had no overt clinical manifestations of glucose intolerance. Diabetic nodular glomerulosclerosis can occur in patients without overt DM, suggesting the role of factors additional to prolonged hyperglycaemia in the pathogenesis of this disorder.

Antiproteinuric effect of candesartan cilexetil in patients with chronic glomerulonephritis.

A prospective, randomised, double-blind, parallel-group, dose-response trial was conducted to investigate the antiproteinuric effect of candesartan cilexetil, the angiotensin II type 1 receptor blocker, in patients with chronic glomerulonephritis. Patients (n=280) were treated for 12 weeks with candesartan cilexetil 2, 4, or 8 mg given orally once-daily (o.d.). The improvement in urinary protein excretion observed at the end of the treatment period was 15.9% in the 2 mg group, 25.6% in the 4 mg group, and 34.6% in the 8 mg group, respectively, showing a clear dose-response (2 mg <4 mg <8 mg; p=0.003). The mean reduction in urinary protein excretion was 11.3% in the 2 mg group, 26.3% in the 4 mg group, and 26.0% in the 8 mg group, showing a dose-response pattern, in that the effect of 4 mg and 8 mg was greater than that of 2 mg (2 mg <4 mg asymptotically equal to 8 mg; p=0.010). As the observed reduction in urinary protein excretion failed to correlate with changes in mean blood pressure, it could not be attributed to the antihypertensive effect of the study drug alone. This suggests that candesartan cilexetil, 4 8 mg o.d., has antiproteinuric effects in patients with chronic glomerulonephritis.