Inhibitory effect of cranberry polyphenol on biofilm formation and cysteine proteases of Porphyromonas gingivalis

BACKGROUND AND OBJECTIVE

The purpose of this study was to investigate the effects of cranberry polyphenol fraction on biofilm formation and activities of Arg-gingipain and Lys-gingipain in Porphyromonas gingivalis.

MATERIAL AND METHODS

The polyphenol fraction was prepared by using a glass column packed with Amberlite XAD 7HP and 70% aqueous ethanol as an elution solvent.

RESULTS

Synergistic biofilm formation by P. gingivalis and Fusobacterium nucleatum was significantly inhibited by the polyphenol fraction at a concentration of 250 microg/mL compared with untreated controls (p < 0.01). Arg-gingipain and Lys-gingipain activities in P. gingivalis ATCC 33277 and FDC 381 were inhibited significantly at a polyphenol fraction concentration of > or = 1 microg/mL (p < 0.05).

CONCLUSION

These findings indicate that the polyphenol fraction inhibits biofilm formation and the Arg-gingipain and Lys-gingipain activities of P. gingivalis.

A series of protein phosphatase gene disruptants in Saccharomyces cerevisiae

Thirty-two protein phosphatase (PPase) genes were identified in the genome nucleotide sequence of Saccharomyces cerevisiae. We constructed S. cerevisiae disruptants for each of the PPase genes and examined their growth under various conditions. The disruptants of six putative PPase genes, i.e. of YBR125c, YCR079w, YIL113w, YJR110w, YNR022c and YOR090c, were created for the first time in this study. The glc7, sit4 and cdc14 disruptants were lethal in our strain background. The remaining 29 PPase gene disruptants were viable at 30 degrees C and 37 degrees C, but only one disruptant, yvh1, showed intrinsic cold-sensitive growth at 13 degrees C. Transcription of the YVH1 gene was induced at 13 degrees C, consistent with an idea that Yvh1p has a specific role for growth at a low temperature. The viable disruptants grew normally on nutrient medium containing sucrose, galactose, maltose or glycerol as carbon sources. The ppz1 disruptant was tolerant to NaCl and LiCl, while the cmp2 disruptant was sensitive to these salts, as reported previously, and none of the other viable PPase disruptants exhibited the salt sensitivity. When the viable disruptants were tested for sensitivity to drugs, i.e. benomyl, caffeine and hydroxyurea, ppz1 and ycr079w disruptants exhibited sensitivity to caffeine.

Partial purification and characterization of sphingosine N-acyltransferase (ceramide synthase) from bovine liver mitochondrion-rich fraction

Sphingosine N-acyltransferase (ceramide synthase, E.C. 2.3.1.24) was solubilized from bovine liver mitochondrion-rich fraction with n-octyl beta-D-thioglucoside as the detergent and partially purified by sequential chromatography on columns of DE-32, shingosine affinity, and Sepharose CL-6B. The partially purified preparation migrated on SDS-polyacrylamide gel electrophoresis as two major protein bands of 62 and 72 kDa. The molecular mass of the enzyme estimated by gel filtration was 240-260 kDa, suggesting that the partially purified enzyme is present in a subunit form or simply has an aggregative nature. The specific activity of the final preparation for the condensation of sphingosine with stearoyl-CoA increased by 98.7-fold compared with the starting material. The optimal pH value for the ceramide synthesis was 7.5. The partially purified enzyme had an apparent Km of 146 microM and a Vmax of 11.1 nmol/min/mg protein for stearoyl-CoA. The Km and Vmax values toward sphingosine were 171 microM and 11.3 nmol/min/mg protein, respectively. Interestingly, sphinganine was also a good substrate for this enzyme, and the Km and Vmax values were 144 microM and 8.5 nmol/min/mg protein, respectively.

Development of hypercalcemic crisis in a Graves' hyperthyroid patient associated with central diabetes insipidus

A 26-year-old man with Graves' hyperthyroidism associated with central diabetes insipidus (DI), initially showed hypercalcemic crisis. Initially, very low serum levels of intact parathyroid hormone (PTH) and 1,25-dihydroxy vitamin D3 and a moderate rise of serum C-terminal PTH related protein (C-PTHrP) were observed which strongly suggested a humoral hypercalcemia of malignancy due to PTHrP. However, the serum C-PTHrP level later became normal. Mild hyperprolactinemia, no responses of growth hormone (GH) to insulin-induced hypoglycemia despite a normal growth hormone releasing hormone (GRH) test and mild thickening of the pituitary stalk on magnetic resonance imaging were observed. Thus, an autoimmune nature of his central DI is considered; it is noteworthy that the serum C-PTHrP level may be elevated by renal failure in patients with hypercalcemia due to causes other than PTHrP.

Antiarrhythmic drugs inhibit the G-protein and K+ channels in the cultured thyroid cell line

We examined the effects of antiarrhythmic drugs on the induction of cAMP by TSH (thyroid-stimulating hormone), using continuously cultured FRTL-5 rat thyroid cells. Group Ia antiarrhythmic drugs had no effect, but Group Ib antiarrhythmic drugs suppressed cAMP induction by TSH. These drugs suppressed cAMP induction in response to cholera toxin but did not inhibit TSH receptor binding or cAMP induction by forskolin. These results indicate that Group Ib antiarrhythmic drugs inhibit thyroid G-protein, resulting in a decrease in cAMP induction by TSH. We also examined the effect of antiarrhythmic drugs on K+ channels. Group Ia antiarrhythmic drugs had no effect on K+ channel activation by TSH and cAMP. On the other hand, Group Ib antiarrhythmic drugs suppressed K+ channel activation by TSH and cAMP. This indicates that the mechanism of suppression is not inhibition of TSH receptors or G-proteins but the direct suppression of K+ channels. Group Ib antiarrhythmic drugs inhibited thyroid Gs-protein and thyroid K+ channels. Considering the close relationship between G-protein and ion channels in the cardiac cell membrane, these different effects of Group Ia and Group Ib antiarrhythmic drugs on G-proteins and K+ channels are of interest. Further investigation is necessary to clarify the relationship between thyroid G-proteins and thyroid K+ channels.

Induction of photoresponse by the hydrolysis of polyphosphoinositides in the Hermissenda type B photoreceptor

Direct evidence that the photoresponse of the Hermissenda type B photoreceptor cell is triggered directly by the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) was obtained. Neomycin and spermine, which inhibit PIP2 breakdown, suppressed light response, while injection of inositol 1,4,5-trisphosphate (IP3), guanosine 5'-(3-O-thio)triphosphate (GTP gamma S), guanosine 5'-(2-O-thio)diphosphate (GDP beta S), cAMP, cGMP did not alter the light-induced Na+ influx underlying the photoresponse. Suppression of the photoresponse was also observed with decrease of total amount of membraneous PIP2 induced by injection of the phosphoinositides (PI) turnover inhibitors, isobutylmethylxanthine (IBMX), LiCl and R 59022.

The TSH-dependent potassium channel in a cloned rat thyroid cell line

We found a TSH-dependent K+ channel in the membrane of a rat thyroid cell line (FRTL-5 cell). This K+ channel is activated by extracellular application of the thyroid stimulating hormone (TSH). Treatment of dibutyryladenosine cyclic monophosphate (Bt2 cAMP) also activated the TSH-dependent K+ channel. Intracellular application of protein kinase A activates this K+ channel without the presence of free Ca2+. These findings indicate that the thyroid K+ channel is activated through the TSH-cAMP-protein kinase A system. This is the first report of a polypeptide hormone activated K+ channel and it should be useful for examining the effects of this K+ channel on thyroid cell functions.

Evaluation of thyroid function in patients with isolated adrenocorticotropin deficiency

Thyroid hormone and thyrotropin (TSH) levels were evaluated before and after adrenal replacement in eight patients (six men and two women, 35-62 years old) with isolated adrenocorticotropin (ACTH) deficiency. Six patients (cases 1-6) showed TSH excess before treatment. Four patients (cases 1-4), who initially had subnormal thyroid hormone levels, showed resolution of biochemical features of primary hypothyroidism after treatment, although TSH excess has persisted in two patients (cases 1 and 2). Case 1 had an extremely high titer of antimicrosomal antibody (MCHA), and cases 2 and 3 showed histologically and cytologically chronic thyroiditis, despite negative results for MCHA and antithyroglobulin antibody, respectively. Two patients (cases 5 and 6), who had had normal thyroid hormone levels and did not show the significant rise in serum T3 in TSH releasing hormone testing, showed TSH normalization without changes in serum thyroid hormone levels after treatment. The other two patients (cases 7 and 8), who initially had normal TSH and thyroid hormone levels, did not show the significant changes in serum TSH and thyroid hormone levels after treatment. The prevalence of chronic thyroiditis coexistence in isolated ACTH deficiency may be higher than predicted. Therefore, TSH excess before adrenal replacement may be attributed to not only direct enhancement of TSH release due to chronic cortisol deficiency but also to thyroid dysfunction due to chronic thyroiditis. It is possible that hypothyroidism due to chronic thyroiditis can be improved only by adrenal supplementation.

Renal handling of urate in two patients with hyperuricemia and primary hyperparathyroidism

Two patients with primary hyperparathyroidism had hyperuricemia due to the decrease in urate clearance. In analysis by 4-component model system, the tubular secretion of urate commonly decreased without changes in either filtered urate or presecretory reabsorption of urate. Both patients had a reduction of urea clearance, and both parathyroidectomy in the former case and intravenous infusion of saline in the latter case could reduce the serum urate level associated with the increase in the ratio of urate clearance to creatinine clearance. It is of interest that the former case with a higher serum urate level had a relatively higher postsecretory reabsorption, even with the decrease in tubular secretion of urate. However, the latter patient with a lower serum urate level had a decrease in postsecretory reabsorption of urate in proportion to the decrease in tubular secretion. These results suggest that in hyperuricemia patients with primary hyperparathyroidism, the reduction of tubular urate secretion via hypoperfusion of the capillary network is typically present, however, the severity of the hyperuricemia might be dependent on the dysfunction of the postsecretory reabsorption of urate.

Detection of Thyroid-Stimulating Antibody in Patients with Inflammatory Thyrotoxicosis

The detection of thyrotropin-binding inhibitory immunoglobulins (TBII) and/or thyroid-stimulating antibody (TSAb) has been reported in some patients with painless thyroiditis (PT) or subacute thyroiditis (SAT). However, its mechanism is unknown. TBII and TSAb measured using cultured FRTL-5 thyroid cells were evaluated in 18 patients with PT, 11 patients with SAT and a patient with SAT-like symptoms. In PT, we detected both TBII and TSAb activities in only 1 patient. This case had first come to our attention with subclinical hypothyroidism and had already had weakly positive TSAb activity (205.9%) 1 year before the present onset of PT. This patient had a transient thyrotoxicosis with a low uptake (24 h) of 123I (4.3%) and 821.0% TSAb activity, and subsequently developed a transient subclinical hypothyroidism. Even after 2 years, she still had positive TSAb activity (382.3%). In SAT, TBII and TSAb activities were not detected during the courses of any patients. A patient with transient thyrotoxicosis, who had a high uptake (30 min) of 99mTc (5.6%) and SAT-like symptoms (painful tenderness on right thyroid lobe and markedly accelerated erythrocyte sedimentation rate), showed positive activities of TBII (34.9%) and TSAb activity (1,366.9%). Histological findings by thyroid needle biopsy performed in the thyrotoxic phase showed coexistence of granulomatous inflammatory changes and hyperplasia with papillary folds of some residual follicular cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Onset of subacute aggravation of chronic thyroiditis followed immediately by transient hypothyroidism during antithyroid drug therapy for Graves' hyperthyroidism

A 56-year-old man presented with clinical and biochemical hyperthyroidism with high thyroid 99mTc uptake, positive result for antimicrosomal antibody (MCHA; 1:8,100) and markedly high activities of thyrotropin-binding inhibitory immunoglobulin (TBII; 90.0%) and thyroid-stimulating antibody (TSAb; 2,400%). Fifty days after the initiation of antithyroid drug therapy, he developed a painful tender enlarged thyroid and an accelerated erythrocyte sedimentation rate (ESR), which were followed immediately by hypothyroidism with a transient increase in MCHA titer (peak; 1:218,700) despite of maintenance of high TBII and TSAb activities. Two and a half months after the recovery from hypothyroidism, recurrent hyperfunction was observed with further elevation of TSAb activity (4,643%). After about 2 weeks, recurrences of a painful tender enlarged thyroid and an accelerated ESR, which were followed by abrupt progression to hypothyroidism, were found. Specimens obtained when he had still slightly tender goiter after the first and second episodes of neck pain showed microscopically extremely extended interstitial fibrosis with collapsed follicles and moderate lymphocytic infiltration. Thyroid-stimulation-blocking antibody was not detected at either onset of hypothyroidism. Thus, it is possible that Graves' disease, subacute aggravation of chronic thyroiditis and hypothyroidism coexist in the same individual. In such patients, thyroid status may be determined by the degree of each of the stimulating factors (TSH, TSAb and/or unknown factors) and suppressive or destructive factors (humoral and/or cellular) and may be changed in a very short interval.

Autoimmune thyroiditis with transient thyrotoxicosis: comparison between painful thyroiditis and painless thyroiditis

Clinical and laboratory findings and long-term outcomes in 8 patients (7 women) with autoimmune thyroiditis (AT), aged 34-59 years, who had a painful tender goiter and a transient thyrotoxicosis with a low thyroid radioactive iodine uptake (RAIU), were compared with those in 15 patients (13 women) with painless thyroiditis (PT), aged 23-69 years. Six painful AT and 6 PT patients had a history of prior awareness of goiter. All patients with painful AT had a moderate or marked elevation of erythrocyte sedimentation rate and a positive result for C-reactive protein, while only 3 PT patients (group B) did. There were no significant differences between the mean age, duration of symptoms, white blood cell count, serum triiodothyronine (T3) and thyroxine (T4) concentrations, serum T3/T4 ratio and duration of thyrotoxicosis after the initial examination and prevalences of positive results for antithyroglobulin and -microsomal antibodies in the two diseases. Two of 8 painful AT patients showed a histologically chronic fibrous variant and 6 others showed chronic lymphocytic thyroiditis. All PT patients examined also showed lymphocytic thyroiditis. Two and 5 painful AT patients developed transient and persistent hypothyroidism, respectively, while 8 [7 in group A (normal ESR), 1 in group B] and 3 PT patients (1 in group A, 2 in group B) did, respectively. The mean serum thyroid-stimulating hormone level in the hypothyroid phase in painful AT patients was higher than that in PT patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Disappearance of thyroid-stimulation blocking antibody by glucocorticoid therapy in a patient with primary myxedema who developed aortitis syndrome during L-thyroxine supplementation

A 39-year-old woman with primary myxedema, who had the potent activities of thyrotropin-binding inhibitory immunoglobulins (TBII) and thyroid-stimulation blocking antibodies (TSBAb), developed aortitis syndrome about 6 months after the initiation of L-thyroxine (L-T4) supplementation. A 35 mg daily dose of prednisolone for aortitis syndrome was initiated, and the dose was gradually reduced. TBII and TSBAb activities were gradually decreased, and both reached normal levels (7.7% and 10.1%, respectively) 3 months after the initiation of prednisolone. Therefore, dose of L-T4 was gradually reduced, and L-T4 supplementation was stopped. Subsequently, however, recurrence of hypothyroidism was not observed. These observations indicate the possibility that hypothyroidism remits with disappearance of TBII and TSBAb activities in not only neonatal cases but also adult cases.