Endotoxin-neutralizing activity and mechanism of action of a cationic α-helical antimicrobial octadecapeptide derived from α-amylase of rice.

We have previously reported that AmyI-1-18, an octadecapeptide derived from α-amylase (AmyI-1) of rice, is a novel cationic α-helical peptide that exhibited antimicrobial activity against human pathogens, including Porphyromonas gingivalis, Pseudomonas aeruginosa, Propionibacterium acnes, Streptococcus mutans, and Candida albicans. In this study, to further investigate the potential functions of AmyI-1-18, we examined its inhibitory ability against the endotoxic activities of lipopolysaccharides (LPSs, smooth and Rc types) and lipid A from Escherichia coli. AmyI-1-18 inhibited the production of endotoxin-induced nitric oxide (NO), an inflammatory mediator, in mouse macrophages (RAW264) in a concentration-dependent manner. The results of a chromogenic Limulus amebocyte lysate assay illustrated that the ability [50% effective concentration (EC50): 0.17 µM] of AmyI-1-18 to neutralize lipid A was similar to its ability (EC50: 0.26 µM) to neutralize LPS, suggesting that AmyI-1-18 specifically binds to the lipid A moiety of LPS. Surface plasmon resonance analysis of the interaction between AmyI-1-18 and LPS or lipid A also suggested that AmyI-1-18 directly binds to the lipid A moiety of LPS because the dissociation constant (KD) of AmyI-1-18 with lipid A is 5.6×10(-10) M, which is similar to that (4.3×10(-10) M) of AmyI-1-18 with LPS. In addition, AmyI-1-18 could block the binding of LPS-binding protein to LPS, although its ability was less than that of polymyxin B. These results suggest that AmyI-1-18 expressing antimicrobial and endotoxin-neutralizing activities is useful as a safe and potent host defense peptide against pathogenic Gram-negative bacteria in many fields of healthcare.

Inhibitory effect of cranberry polyphenol on cariogenic bacteria.

The purpose of this study was to investigate the effect of cranberry polyphenol fraction on mutans streptococci. Hydrophobicity is an important factor in the adherence of bacteria to the tooth surface. We found that cranberry polyphenol fraction significantly decreased the hydrophobicity of Streptococcus sobrinus 6715, Streptococcus mutans MT8148R and JC2 in a dose-dependent manner (p<0.05). Biofilm formation by S. sobrinus 6715 and S. mutans MT8148R was inhibited by 100 microg/ml cranberry polyphenol fraction (p<0.01). When dosage was increased to 500 microg/ml, biofilm formation by S. mutans JC2 was significantly inhibited (p<0.05). Addition of 500 microg/ml cranberry polyphenol fraction to medium inhibited growth of S. mutans MT8148R compared with the control (p<0.05).

Evaluation of anorectal function in patients with tethered cord syndrome: saline enema test and fecoflowmetry.

OBJECT: Disturbance in anorectal function is a major factor restricting the activities of daily living in patients with spinal cord disorders. To detect changes in anorectal motilities due to a tethered spinal cord, anorectal functions were evaluated using a saline enema test and fecoflowmetry before and after patients underwent untethering surgery. METHODS: The bowel functions in five patients with a tethered cord syndrome (TCS) were evaluated by performing a saline enema test and fecoflowmetry. The contractile activity of the rectum, the volume of infused saline tolerated in the rectum, anal canal pressure, and the ability to evacuate rectal content were examined. The characteristic findings in anorectal motility studies conducted in patients with TCS were a hyperactive rectum, diminished rectal saline-retention ability, and diminished maximal flow in saline evacuation. A hyperactive rectum was considered to be a major contributing factor to fecal incontinence. In one asymptomatic patient diminished anal squeezing pressure was exhibited and was incontinent to liquid preoperatively, but recovered after surgery. Two patients who underwent surgery for myeloschisis as infants complained of progressive fecal incontinence when they became adolescents. In one patient fecal incontinence improved but in another patient no improvement was observed after untethering surgery. CONCLUSIONS: Fecodynamic studies allow the detection of neurogenic disturbances of the anorectum in symptomatic and also in asymptomatic patients with TCS. More attention should be paid to the anorectal functions of patients with TCS.

Renal focal tubulointerstitial fibrosis with short bowel syndrome: report of a case.

We report a male patient with short bowel syndrome (SBS) and renal focal tubulointerstitial fibrosis (FTIF). Seven years after surgery, he was introduced to us due to severe undernutrition, an impairment of growth hormone (GH) secretion, and abnormally low levels of plasma citrulline and arginine at 11 years 7 months of age, just before nutritional support using total parenteral nutrition (TPN) was begun. Thereafter, the support was changed to home TPN with GH supplementation. After an improvement of the disorders, GH was stopped at 17 years 3 months of age. However, hyperuricemia appeared and a renal biopsy revealed FTIF at 20 years of age. Home TPN was continued twice a week because the plasma arginine level was still low. His follow-up biopsy at 23 years of age showed morphometric amelioration. Arginine deficiency following SBS may be associated with FTIF. The cause of hyperuricemia after SBS therefore needs to be investigated in detail.

Evaluation of anorectal functions of children with anorectal malformations using fecoflowmetry.

BACKGROUND/PURPOSE: A simple and objective method evaluating the bowel functions of patients with anorectal anomalies is necessary. The authors applied fecoflowmetry and saline enama test for patients with anorectal anomalies to evaluate the fecodynamics and anorectal motilities in these children. METHODS: The bowel functions of 16 patients who underwent repair for anorectal malformations and 5 normal controls were evaluated by saline enema test and fecoflowmetry. The correlations between the clinical scores for the bowel functions and the parameters in fecodynamic studies were investigated. RESULTS: Seven of 16 patients exhibited periodical contractions of the rectum synchronized with relaxations of the anal canal during saline infusion as did the controls and had significantly higher clinical scores than the other patients. Two patients with severe chronic constipation lacked rectal contractions. Among the fecoflowmetric parameters, the maximum flow, average flow, and tolerable volume of saline infused into the rectum were significantly lower in the patients with low clinical scores than those of the controls. The maximal squeeze pressure and resting anal pressure were not significantly different between the patients and controls. CONCLUSION: Fecodynamic studies, such as fecoflowmetry and saline enema test, help in obtaining clinical indicators for the bowel functions of patients with anorectal anomalies.