Diabetes as a risk factor for periodontal disease—plausible mechanisms

The present narrative review examines the scientific evidence of the biological mechanisms that may link periodontitis and diabetes, as a source of comorbidity. Publications regarding periodontitis and diabetes, in human, animals, and in vitro were screened for their relevance. Periodontal microbiome studies indicate a possible association between altered glucose metabolism in prediabetes and diabetes and changes in the periodontal microbiome. Coinciding with this, hyperglycemia enhances expression of pathogen receptors, which enhance host response to the dysbiotic microbiome. Hyperglycemia also promotes pro-inflammatory response independently or via the advanced glycation end product/receptor for advanced glycation end product pathway. These processes excite cellular tissue destruction functions, which further enhance pro-inflammatory cytokines expression and alteration in the RANKL/osteoprotegerin ratio, promoting formation and activation of osteoclasts. The evidence supports the role of several pathogenic mechanisms in the path of true causal comorbidity between poorly controlled diabetes and periodontitis. However, further research is needed to better understand these mechanisms and to explore other mechanisms.     

Ultraflex expandable stents for the management of air leaks.

Postoperative empyema and aspergillosis were diagnosed in a 66-year-old man. Since non-operative therapy was not effective, we performed surgery. On the 8th postoperative day, a covered Ultraflex expandable stent (Boston Scientific, Galway, Ireland) was implanted to make a one-way airway for blocking a major air leak from a bronchopleural fistula causing respiratory distress. His general condition improved gradually, and he was discharged 30 days after stenting. In conclusion, we used a covered Ultraflex expandable stent to make an airway to block an air leak. This may be a new application for this stent.     

Effects of anthocyanidin derivative (HK-008) on relaxation in rat perfused mesenterial bed.

Anthocyanins, which are responsible for a variety of bright colors (including red, blue, and purple) in fruits, vegetables, and flowers, are consumed as dietary polyphenols. Anthocyanin-containing fruits are thought to decrease coronary heart disease and are used in anti-diabetic preparations. Diabetes is associated with a variety of cardiovascular complications that may be mediated by endothelial dysfunction, and so this study was designed mainly to characterize the influence of a synthesized anthocyanidin derivative (HK-008) over acetylcholine (ACh)-induced relaxation in mesenteric arterial beds isolated from rats. In a glucose-tolerance test in intact rats, HK-008 (30 mg/kg) reduced the glucose level as effectively as the same dose of glibenclamide. The aortic relaxation induced by pinacidil (an ATP-sensitive potassium channel opener) was greatly inhibited by glibenclamide (10 microM), and also significantly inhibited by HK-008 (10 microM). Interestingly, the ACh-induced relaxation in the perfused, preconstricted mesenteric arterial bed was significantly enhanced by HK-008 (10 microM), and this enhancement was significantly attenuated by indomethacin (10 microM). The ACh-induced mesenteric relaxation was impaired by an increase in oxidative stress, viz. superoxide-generating treatment [xanthine oxidase (XO; 0.1 U/ml) plus hypoxanthine (HX; 10 microM)]. However, this impairment was strongly suppressed by HK-008 (10 microM). These results suggest that HK-008 increases endothelium-induced relaxation by suppressing oxidative stress or modulating prostanoids signaling. This compound may therefore be useful against certain cardiovascular disorders.     

CROSSOVER COMPARISON BETWEEN THE DEPRESSOR EFFECTS OF LOW AND HIGH WORK-RATE EXERCISE IN MILD HYPERTENSION

1. The relationship between work-rate and the antihypertensive effect of exercise in hypertensives, and the mechanism of that effect, were investigated by a crossover clinical trial. 2. Ten mild hypertensives were randomly divided into two groups. One group performed low work-rate exercise (LWE) on a cycle ergometer for 10 weeks (blood lactate threshold; ～50% of maximum oxygen consumption [V?_O2max]). After a 10 week interval without exercise training, these subjects were then switched to a high work-rate exercise (HWE) regimen (4 mmol/ L of blood lactate; ～75% of V?_O2max) for another 10 weeks. In the other group, the order of exercise training was reversed. Since two patients withdrew from the protocol during HWE periods, statistical analysis was performed on the data from the remaining eight patients. There were no order effects observed in any of the data from the two groups. 3. During both LWE and HWE, resting blood pressure (BP) fell significantly after the initiation of exercise therapy (P<0.05). Furthermore, the overall effects of 10 weeks of LWE and HWE on BP were not significantly different. 4. The work-rate at the lactate threshold, which reflects physical fitness, had increased significantly by 16 W (P<0.01) after the LWE period and by 11 W (P<0.01) after the HWE. 5. During the LWE period, changes in haemodynamic and humoral variables were not significant, except for a reduction in plasma norepinephrine at week 10 (P<0.05). In the HWE period, changes in haemodynamic and humoral variables were not significant. 6. Based on these findings, LWE is recommended for mild hypertensives because of its safety.     

Superoxide dismutase-like immunoreactivity in spheroids in Hallervorden-Spatz disease

Iron accumulation in the basal ganglia and spheroid formation are pathological hallmarks of Hallervorden-Spatz disease (HS). Since an overaccumulation of iron (iron thesaurosis) that exceeds the binding capacity of ferritin could cause oxidative damage, we studied the possible role of oxidative stress in the pathogenesis of HS. The basal ganglia and spinal cord from patients with HS were investigated at autopsy, using histochemistry for iron and immunohistochemistry for Cu/Zn superoxide dismutase (SOD1), Mn superoxide dismutase (SOD2) and ferritin. SOD1-like immunoreactivity (IR), SOD2-IR and ferritin-IR occurred frequently in spheroids observed in the basal ganglia, and associated iron accumulation indicated the possible existence of increased oxidative stress in HS patients. Spheroids in the spinal cord showed intense SOD1-IR and SOD2-IR in HS, in sharp contrast with the occasional weak SOD1-IR and SOD2-IR observed in spheroids from patients with amyotrophic lateral sclerosis (ALS). Neither increased ferritin-IR nor iron accumulation were observed in spinal spheroids from HS and ALS patients. These data may suggest that, at least in the spinal cord, SOD1-IR and SOD2-IR in spheroids in HS patients do not result from oxidative stress directly related to iron accumulation. Received: 15 March 1996 / Revised accepted: 15 July 1996     

Evaluation of 2,3,5-triphenyltetrazolium chloride staining to delineate rat brain infarcts.

BACKGROUND AND PURPOSE: Accurate and reproducible determination of the size and location of cerebral infarcts is critical for the evaluation of experimental focal cerebral ischemia. The purpose of this study was to compare intracardiac perfusion of 2,3,5-triphenyltetrazolium chloride with immersion of brain tissue in 2,3,5-triphenyltetrazolium chloride to delineate brain infarcts in rats. METHODS: After 6, 24, or 48 hours of ischemia induced by permanent middle cerebral artery occlusion, some rats were perfused with 2,3,5-triphenyltetrazolium chloride; other rats were given an overdose of barbiturates, after which brain sections were immersed in 2,3,5-triphenyltetrazolium chloride. Coronal sections were taken 4, 6, and 8 mm from the frontal pole, and infarct areas in perfused and immersed sections were compared; subsequently, the same sections were stained with hematoxylin and eosin. RESULTS: In rats subjected to 24 or 48 hours of occlusion, areas of infarction were clearly defined with both 2,3,5-triphenyltetrazolium chloride staining techniques, and the infarct sizes correlated well with the results of hematoxylin and eosin staining (r = 0.85-0.94). CONCLUSIONS: These results demonstrate that intracardiac perfusion of 2,3,5-triphenyltetrazolium chloride is an accurate, inexpensive, and efficient staining method to detect infarcted tissue 24 and 48 hours after the onset of ischemia in rats.     

Cerebral perfusion scintigraphy in patients with cerebrovascular disease by using 99mTc-ECD: comparative study with 123I-IMP SPECT

99mTc-ECD SPECT was performed in 19 patients with cerebrovascular disease, and location, extent, and severity of the lesions on 99mTc-ECD SPECT were compared with those on 123I-IMP SPECT. The initial brain uptake was 5.5 +/- 0.7% of the injected dose at 10 minutes after injection, 5.3 +/- 1.3% at 90 minutes, and clearance from the brain is slow. The distribution in the brain was changed, especially washout from the thalamus was slower than that from other regions. The count ratio of perfusion defect to normal area (D/N) on 99mTc-ECD SPECT was unchanged over the time, and had no significant differences from that on 123I-IMP SPECT. 99mTc-ECD SPECT was superior in detection of the lesion in the basal ganglia, and showed the images with superior spatial resolution due to physical characteristics of 99mTc. However, mild ischemic lesion and peri-infarct area was not clearly visualized, while 123I-IMP SPECT could demonstrate these lesions with better contrast.