Atsuko Igarashi

Identification of the Putrescine Recognition Site on Polyamine Transport Protein PotE

The PotE protein can catalyze both uptake and excretion of putrescine. The K m values of putrescine for uptake and excretion are 1.8 and 73 μm, respectively. Uptake of putrescine is dependent on the membrane potential, whereas excretion involves putrescine-ornithine antiporter activity. Amino acids involved in both activities were identified using mutated PotE proteins. It was found that Cys62, Trp201, Trp292, and Tyr425 were strongly involved in both activities, and that Tyr92, Cys210, Cys285, and Cys286 were moderately involved in the activities. Mutations of Tyr78, Trp90, and Trp422 mainly affected uptake activity, and the K m values for putrescine uptake by these PotE mutants increased greatly, indicating that these amino acids are involved in the high affinity uptake of putrescine by PotE. Mutations of Lys301 and Tyr308 mainly affected excretion activity (putrescine-ornithine antiporter activity), and excretion by these mutants was not stimulated by ornithine, indicating that these amino acids are involved in the recognition of ornithine. It was found that the putrescine and ornithine recognition site on PotE is located at the cytoplasmic surface and the vestibule of the pore consisting of 12 transmembrane segments. Based on the results of competition experiments with various putrescine analogues and the disulfide cross-linking of PotE between cytoplasmic loops and the COOH terminus, a model of the putrescine recognition site on PotE consisting of the identified amino acids is presented.

Intense correlation between protein-conjugated acrolein and primary Sjögren's syndrome

BACKGROUND We recently found that an increased plasma concentration of protein-conjugated acrolein is a good biomarker for stroke. Therefore we determine whether the concentration of protein-conjugated acrolein is increased in saliva from patients with primary Sjögrens syndrome. METHODS Stimulated whole-mixed saliva was collected from 10 patients and 13 control subjects. The concentration of protein-conjugated acrolein in saliva and plasma was measured by either Western blotting or enzyme-linked immunosorbent assay. RESULTS The concentration of protein-conjugated acrolein, especially albumin-conjugated acrolein, was greatly increased in saliva from patients with primary Sjögrens syndrome (p<0.001). The concentration of protein-conjugated acrolein was inversely correlated with the flow rate of saliva. CONCLUSION The results indicate that the concentration of protein-conjugated acrolein, a marker of cell or tissue damage, in saliva is well correlated with seriousness of primary Sjögrens syndrome.

Effects of Food Consistency on Tongue Pressure during Swallowing

Tongue pressure against the anterior and posterior portions of the hard palate as well as the electromyographic activity of suprahyoid muscle during swallowing test foods with three different consistencies (thinned, medium, and thickened paste) and liquid were recorded. Significant differences and wide variations were noted in the peak amplitude and area of posterior tongue pressure, which was larger for thickened paste compared to liquid, thinned, and medium pastes. Regarding the anterior tongue pressure, the duration was significantly longer during swallowing thickened paste compared to liquid and thinned paste, while there were no differences in the peak amplitude and area. The results suggest that a basic pattern of tongue pressure is maintained during swallowing but is modulated by sensory feedback in a different manner between the anterior and posterior portions of the tongue to complete propulsion of the bolus in the oral cavity.

Relationships between the amount of saliva and medications in elderly individuals

OBJECTIVE To investigate medications that are related to volume of saliva in the elderly. BACKGROUND DATA In the elderly, many cases of mouth dryness may represent side effects of medication. MATERIALS AND METHODS The volume of unstimulated saliva was measured for 30 s (cotton roll test), and with stimulation for 3 min (gum test) in 368 subjects 79-80 years old (177 men, 191 women). Medications were investigated using subjects medication notebooks. RESULTS Mean volumes of unstimulated and stimulated saliva were 0.14±0.13 and 4.30±2.54 ml respectively. Significant differences were seen between gender and mean volume of saliva. The volume of unstimulated saliva was 0.16±0.15 ml for men and 0.11±0.10 ml for women. The volume of stimulated saliva was 4.99±2.67 ml for men and 3.67±2.25 ml for women. The percentage of subjects taking medication was 64.7% (238/368). Mean number of medications was 2.08±2.26, with no significant difference with gender (2.01±2.37 for men, 2.16±2.16 for women). In a stepwise multiple regression analysis with volume of saliva as the objective variable and number of drugs by category as explanatory variables, significant explanatory variables in addition to gender and number of medications were blood-coagulating agents, Ca antagonists and peptic ulcer drugs for volume of unstimulated saliva, and diabetes medications and peptic ulcer drugs for volume of stimulated saliva. CONCLUSION These findings suggest that differences exist between gender in volume of saliva for elderly individuals, and that the volume of saliva is affected by the number and type of medications.

Salivary spinability and periodontal disease progression in an elderly population

OBJECTIVE To explore the relationship between the spinability of stimulated whole saliva and periodontal disease progression over 12 months in an elderly population. METHODS Three hundred and thirty-two subjects aged 76 years at baseline were studied. Attachment loss was calculated on a site-by-site basis, and periodontal disease progression was defined as an attachment loss of >or=3mm. Stimulated whole saliva was collected and salivary spinability (SS) was measured. A multiple linear regression analysis was performed to assess the relationship between periodontal disease progression and SS after controlling for other covariates. The independent variables were selected from those which had significant relationships with disease progression in the bivariate analyses. RESULTS Mean SS was 1.94+/-0.42 mm in males and 1.88+/-0.32 mm in females; this difference was not significant. Simple linear regression analysis showed a significant positive relationship between periodontal disease progression and SS (P=0.026), whereas there was no significant relationship between periodontal disease progression and salivary flow rate. Multiple regression analysis revealed a significant positive relationship between periodontal disease progression and SS (P=0.024) after controlling for the number of remaining teeth and baseline periodontal conditions. The model explained 15.5% of the variance in the percentage of sites where the disease had progressed. CONCLUSIONS These findings suggest that elderly subjects with viscous saliva are prone to periodontal disease progression.

Current Status of Salivary Gland Diseases: Sjögren's Syndrome and Dry Mouth

Abstract As societies age, the number of people complaining of dry mouth is increasing; an estimated 30,000,000 people suffer from dry mouth in Japan. The mouth fulfills many basic human appetites, such as eating, drinking, tasting, and talking, and a core component of these functions is saliva. In this paper we will; (1) Explain what dry mouth is; (2) Introduce Niigata University Medical and Dental Hospitals dry mouth outpatient clinic; (3) Describe a new diagnostic method using ultrasonic waves; and (4) Describe salivary protein analysis in patients suffering from Sjogrens syndrome (SS).

Partial sequencing of two forms of concanavalin a-unbound collagenase inhibitor from bovine gingiva

Three forms of collagenase inhibitor, one ConA-bound and two ConA-unbound, were extensively purified from bovine gingiva by sequential column chromatography. Analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed that inhibitory activity resides in proteins with M(r) of 26000-28000 and 22000 for ConA-bound and two ConA-unbound inhibitors, respectively. Of these, two ConA-unbound inhibitors were partially sequenced in the first 12 amino acids and found to have an identical sequence. The NH2-terminal sequence had 100% identity with TIMP-2 or MI.

A stimulating factor for DNA transcription from rat liver

Abstract A stimulating factor for the transcription of rat liver DNA was purified from rat liver supernatant and the mode of action of the factor was studied. The results are summarized as follows. 1. 1. The factor had no detectable activity as a template DNA and polymerase but could promote the transcription of rat liver DNA by a purified Escherichia coli RNA polymerase. 2. 2. It is suggested by the experiment on the incorporation of [γ-32P]ATP and by the sedimentation analysis of RNA synthesized in vitro that the factor functions in the initiation of RNA synthesis but not in the chain elongation. 3. 3. The possibility of template specificity of the factor is briefly discussed.