Isolation and characterization of fimbriae from a sparsely fimbriated strain of Porphyromonas gingivalis

Porphyromonas gingivalis W50 (ATCC 53978) possesses the gene for fimbriae; however, the surface-expressed fimbriae are sparse and have not been previously isolated and characterized. We purified fimbriae from strain W50 to homogeneity by ammonium sulfate precipitation and reverse-phase high-performance liquid chromatography [H. T. Sojar, N. Hamada, and R. J. Genco, Protein Expr. Purif. 9(1):49-52, 1997]. Negative staining of purified fimbriae viewed by electron microscopy revealed that the fimbriae were identical in diameter to fimbriae of other P. gingivalis strains, such as 2561, but were shorter in length. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, the apparent molecular weight of isolated fimbrillin from strain W50 was found to be identical to that of the fimbrillin molecule of strain 2561. Unlike 2561 fimbriae, W50 fimbriae, under reducing condition, exhibited a monomeric structure on SDS-PAGE at room temperature. However, under nonreduced conditions, even at 100 degrees C, no monomer was observed. In immunoblot analysis as well as immunogold labeling of isolated fimbriae, polyclonal antibodies against 2561 fimbriae, as well as antibodies against peptide I (V-V-M-A-N-T-G-A-M-E-V-G-K-T-L-A-E-V-K-Cys) and peptide J (A-L-T-T-E-L-T-A-E-N-Q-E-A-A-G-L-I-M-T-A-E-P-Cys), reacted. However, antifimbrial antibodies against strain 2561 reacted very weakly compared to anti-peptide I and anti-peptide J. Negative staining of whole W50 cells, as well as immunogold electron microscopy with anti-peptide I and anti-peptide J, showed fimbriae shorter in length and very few in number compared to those of strain 2561. Purified fimbriae showed no hemagglutinating activity. Amino acid composition was very similar to that of previously reported fimbriae of the 2561 strain.

A role for fimbriae in Porphyromonas gingivalis invasion of oral epithelial cells

Isogenic mutants of Porphyromonas gingivalis which differ in the expression of fimbriae were used to examine the contribution of fimbriae in invasion of a human oral epithelial cell line (KB). At a multiplicity of infection of 100, the wild-type P. gingivalis strains 33277, 381, and A7436 exhibited adherence efficiencies of 5.5, 0.11, and 5.0%, respectively, and invasion efficiencies of 0.15, 0.03, and 0.10%, respectively. However, adherence to and invasion of KB cells was not detected with the P. gingivalis fimA mutants, DPG3 and MPG1. Adherence of P. gingivalis wild-type strains to KB cells was completely inhibited by the addition of hyperimmune sera raised to the major fimbriae. Examination by electron microscopy of invasion of epithelial cells by the P. gingivalis wild-type strain 381 revealed microvillus-like extensions around adherent bacteria; this was not observed with P. gingivalis fim mutants. Taken together, these results indicate that the P. gingivalis major fimbriae are required for adherence to and invasion of oral epithelial cells.

High-performance liquid chromatographic separation of Porphyromonas gingivalis fimbriae

Fimbriae are responsible for the adherence of many bacterial species to the surfaces they eventually colonize. Porphyromonas gingivalis is an important pathogenic agent involved in periodontal disease. Fimbriae of P. gingivalis have been thought to mediate binding of the bacterium to oral surfaces. In order to study the role of fimbriae in microbial adhesion, it is important to purify fimbriae to homogeneity. A simple and rapid reverse-phase high-performance liquid chromatography (HPLC) method is developed to purify P. gingivalis fimbriae. The crude fimbriae were precipitated from sonic extract of P. gingivalis cells with the 40% ammonium sulfate precipitation. The dialyzed crude fimbriae preparation was subjected to reverse-phase HPLC separation. The purity and size of purified fimbrial proteins were confirmed by SDS-polyacrylamide gel electrophoresis(SDS-PAGE) followed by Western immunoblot using polyclonal antibodies against fimbriae. The purified major fimbrial protein from strain 33277 of P. gingivalis had apparent molecular mass of 41 kDa. The method is useful for analytical as well as preparative purification with 25% yields from the ammonium sulfate-precipitated crude fimbriae preparation, and represents increased speed and efficiency over earlier published methods.

In vivo effect of OPC15161, a superoxide scavenger, on anti-Thy1 nephritis

The in vivo effect of 6-(1 H-indol-3-ylmethyl)-5-methoxy-3-(2-methylpropyl)-2(1 H)-pyrazinone, 4-oxide (OPC15161), a superoxide scavenger, was studied in rats with anti-Thy1 nephritis. Rats were divided into 4 groups: G-1, normal control; G-2, anti-Thy1 nephritis; G-3 anti-Thy1 nephritis and treated with OPC15161 (50 mg/kg/day) starting at day 0; and G-4, anti-Thy1 nephritis and treated with OPC15161 starting 3 days before antibody injection. At weeks 2 and 8, rats were killed for morphological study and at week 8 for renal clearance. Results were compared among the 4 groups. OPC15161 suppressed urinary albumin/day. Total glomerular cells, mesangial cells, ED-1-positive cells/glomerulus and glomerular volume all increased and the increases were suppressed by OPC15161. Tubulointerstitial index, assessed by point counting, was improved by OPC15161 (P < 0.05 G-3, 4, vs. G-2, not significant vs. G-1). Glomerular filtration rate decreased in all nephritic animals, but the decrease in renal blood flow was less in the treated groups. These findings indicate a favorable effect of OPC15161 on the glomerular and interstitial lesions of anti-Thy1 nephritis.

Expression of functional Porphyromonas gingivalis fimbrillin polypeptide domains on the surface of Streptococcus gordonii

Genetically engineering bacteria to express surface proteins which can antagonize the colonization of other microorganisms is a promising strategy for altering bacterial environments. The fimbriae of Porphyromonas gingivalis play an important role in the pathogenesis of periodontal diseases. A structural subunit of the P. gingivalis fimbriae, fimbrillin, has been shown to be an important virulence factor, which likely promotes adherence of the bacterium to saliva-coated oral surfaces and induces host responses. Immunization of gnotobiotic rats with synthetic peptides based on the predicted amino acid sequence of fimbrillin has also been shown to elicit a specific immune response and protection against P. gingivalis-associated periodontal destruction. In this study we engineered the human oral commensal organism Streptococcus gordonii to surface express subdomains of the fimbrillin polypeptide fused to the anchor region of streptococcal M6 protein. The resulting recombinant S. gordonii strains expressing P. gingivalis fimbrillin bound saliva-coated hydroxyapatite in a concentration-dependent manner and inhibited binding of P. gingivalis to saliva-coated hydroxyapatite. Moreover, the recombinant S. gordonii strains were capable of eliciting a P. gingivalis fimbrillin-specific immune response in rabbits. These results show that functional and immunologically reactive P. gingivalis fimbrillin polypeptides can be expressed on the surface of S. gordonii. The recombinant fimbrillin-expressing S. gordonii strains may provide an effective vaccine or a vehicle for replacement therapy against P. gingivalis. These experiments demonstrated the feasibility of expressing biologically active agents (antigens or adhesin molecules) by genetically engineered streptococci. Such genetically engineered organisms can be utilized to modulate the microenvironment of the oral cavity.

Isolation and characterization of a minor fimbria from Porphyromonas gingivalis

We have discovered two distinctly different fimbriae expressed by the same Porphyromonas gingivalis strain. The construction of a fimA mutant of P. gingivalis ATCC 33277 has previously been reported by N. Hamada et al. (Infect. Immun. 62:1696-1704, 1994). Expression of fimbriae on the surface of the fimA mutant and the wild-type strain, ATCC 33277, were investigated by electron microscopy. The wild-type strain produced long fimbrial structures extending from the cell surface, whereas those structures were not observed on the fimA mutant. However, short fimbrial structures were seen on the surface of the fimA mutant. The short fimbrial protein was purified from the fimA mutant by selective protein precipitation and chromatography on DEAE Sepharose CL-6B. We have found that the second fimbrial structure of P. gingivalis ATCC 33277 is distinct from the 41-kDa (43-kDa) major fimbrial protein (FimA). We provisionally call this protein minor fimbriae. The molecular mass of the minor fimbriae is 67 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions after boiling at 100 degrees C. The component shows a ladder-like pattern at 80 degrees C under nonreducing conditions, suggesting a tendency to aggregate or polymerize. In immunoblotting analysis, anti-minor fimbria serum reacted with both the 100 degrees C- and the 80 degrees C-treated minor fimbriae. The anti-minor fimbria serum also reacts with the same-molecular-size fimbrial preparation from the wild-type strain. Immunogold electron microscopy showed that the anti-minor fimbria serum bound to the minor fimbria on the cell surface of the wild-type strain. This is the first report on the identification of the minor fimbria produced by P. gingivalis. These results suggest that the minor fimbriae appearing on the fimA mutant strain are produced together with numerous long major fimbriae on the wild-type strain. Moreover, the minor fimbriae are different in size and antigenicity from the earlier-reported FimA, a major 41-kDa fimbrial component of P. gingivalis.

An automated and portable low-flow pulsatile perfusion system for organ preservation

While machine preservation reduces the incidence of delayed graft function in renal transplant recipients, it is only used in 10% of kidney transplantations. The performance of our portable, low-flow-pulsatile organ perfusion system was examined in a canine kidney autotransplantation model. Grafts were stored for 72 h by simple cold preservation in University of Wisconsin (UW) solution, or by high or low-flow machine preservation After preservation, the grafts were autotransplanted and the animals were followed for 15 days. Graft function was better in machine-preserved kidneys. Tissue biochemistry indicated that machine preservation resulted in higher levels of adenine nucleotides and better histological integrity than the cold storage. While histology and biochemistry of machine-preserved groups were similar, electromicroscopy of high-flow grafts showed mild accumulation of intravenous debris and endothelial swelling. This study shows that a simplified machine perfusion technique is effective for organ preservation.

Glutamine metabolism of intestine grafts: influence of mucosal injury by prolonged preservation and transplantation

The demand for glutamine increased only in the preserved intestine in the early postoperative period (3 days after transplantation). Glutamine demand of the preserved grafts returned to control and immediate levels 7 and 14 days after transplantation. Three days after intestinal transplantation, when the intestinal mucosa was actively regenerating, the demand for glutamine was markedly enhanced. The enhanced demand for glutamine was met by increased output of glutamine by the liver and skeletal muscle. Glutamine uptake by the intestinal graft was enhanced by a brief infusion of glutamine. Thus, we believe exogenous glutamine supplementation may be beneficial for the recovery of intestinal grafts with severe mucosal injury.

Sequential alteration of proto-oncogene expression in liver, spleen, kidney and brain of mice subjected to whole body irradiation

Reverse transcription polymerase chain reaction (RT-PCR) was performed to evaluate the sequential alteration of proto-oncogene mRNA expression in liver, spleen, kidney and brain of mice after whole body irradiation (WBI). The mRNAs investigated in this study were Fas, c-fos, c-myc. bcl-2, and p53, and glyceraldehyde-3-phosphate dehydrogenase mRNA was employed as internal control. C3H/He mice aged 9-10 weeks were exposed to WBI of 7 Gy using a cobalt-60 teletherapy unit, without anesthesia, and sacrificed before and 0.1, 0.5, 1, 2, 3, 6, 12, 24, 48 and 96 h after irradiation. Their liver, spleen, kidney and brain were taken and immediately stored in liquid nitrogen until ready for RT-PCR. Each specimen was homogenized to extract RNA for conventional RT-PCR. The liver of mice administered 7 Gy of WBI revealed no significant changes in the expression of each of the mRNAs examined. In the spleen, c-fos mRNA expression decreased at 2 h following irradiation, and increased remarkably thereafter. In the kidney, no significant change in the expression of each mRNA was shown. In the brain c-fos mRNA expression decreased 1-24 h after irradiation, and showed a recovery thereafter. The remarkable differences in the sequential changes of c-fos mRNA expression following irradiation between each organ revealed by the present experiment may be an important aid in determining the tissue-specific radiosensitivity to ionizing radiation. Further investigations are, however, needed to clarify the signal transduction mechanisms which are mediated by the expression of these proto-oncogenes in each tissue following irradiation.

Sympathetic overactivity of intraocular muscles evaluated by accommodation in patients with hyperthyroidism

Sympathetic overactivity occurs in Graves' disease, but little is known about autonomic nervous function in the eyes of subjects with this disease. We examined this function of the intraocular muscles in 12 patients with hyperthyroid Graves' disease and 12 healthy controls. Pupil size, pupillary unrest, and accommodation were measured with a computer-assisted infrared optometer and pupillometer. The mean and the coefficient of variation of the areas of the pupils were used to express pupil size and the degree of pupillary unrest, respectively. Accommodation was measured with the target light beam moving slowly and steadily, or instantaneously, and the results are expressed as the change in the eye's refractive power in response to these movements. The mean pupil size of the patients was not different from that of the controls. Pupillary unrest in the patients was smaller than in the controls. Accommodation in the patients was lower than that of the controls. Five patients were examined again 3 months later when they became euthyroid; pupillary unrest and accommodation had improved in all five patients. There were no significant differences in the activity of sympathetic nerves governing intraocular muscles in patients with or without eyelid retraction. These results indicate that intraocular muscles are sympathetically overactive in patients with hyperthyroidism, and suggest that eyelid retraction is not caused by sympathetic overactivity alone, but by another factor or factors, in addition.

Intestinal neuromuscular function after preservation and transplantation

While it is well known that prolonged preservation of the intestinal graft causes severe mucosal damage after transplantation, little is known about the effect on neuromuscular function. The entire small intestine of adult hound dogs was flushed and preserved with cold lactated Ringer's solution and autotransplanted either immediately (n = 6) or after 24 hr (n = 6). Animals undergoing sham operation (n = 4) were used as a control. Fasting motility and the response of the intestinal smooth muscle and enteric nerves to bethanechol (100 microg/kg/0.5 hr, iv) and cisapride (0.5 mg/kg, iv) were determined by a multiple strain gauge method on Postoperative Days 2,4,7,14,21, and 28. Compared to the control, immediately transplanted grafts and those preserved for 24 hr developed delayed reappearance of migrating myoelectric complexes (MMC), hypercontractile activity, and reduced response to bethanechol and cisapride administration. Animals in the preservation group developed more abnormal fasting motility after transplantation, but responses to bethanechol and cisapride stimulation were not markedly different from those of the immediate group. The reappearance of MMC occurred 3 weeks postoperatively in the preservation group compared to 2 days in the immediate group. The results of our study indicate that intestinal dysmotility is augmented in prolonged-preservation grafts compared to those with brief preservation. The dysmotility was transient and normalized 3 to 4 weeks after surgery. Preservation and reperfusion injury to the neuromuscular system of intestinal grafts are reversible and are attenuated by simple hypothermia.

Changes in significance of axillary lymph node dissection for patients with breast cancer

Axillary lymph node dissection has been a routine part of breast cancer treatment for more than 100 years. As so few patients have been shown to have positive nodes, more consideration should be given to eliminating axillary node dissection for duct carcinoma in situ (DCIS) and T1a lesions. And for patients with T1/2N0M0 cancer of the breast, lumpectomy alone without axillary dissection followed by radiation therapy of the intact breast and regional lymph nodes should be a reasonable treatment without any arm morbidity. Between September 1989 and September 1994, we have treated 40 breast cancer patients with this method and no local recurrence nor distant metastasis has been encountered so far. Therefore, it is concluded that axillary dissection should be performed routinely only for N1b lesions and larger.

Lazaroid U-74389G for 48-hour canine liver preservation

Lazaroids have been reported to attenuate preservation and reperfusion injury. In this study, we examined whether lazaroids can improve the outcome after 48-hr canine liver preservation and transplantation. Adult female beagle dogs were randomized into 4 dosage groups (5 animals each). Lazaroid U-74389G was intravenously administered at a dose of 0 mg/kg, 6 mg/kg, 10 mg/kg, or 15 mg/kg to donors 30 min before harvesting and also to recipients 30 min before revascularization. Control animals (0 mg/kg) were given the lazaroid vehicle. The liver grafts were orthotopically transplanted after 48 hr of hypothermic preservation in UW solution. Lazaroid treatment significantly improved outcome after transplantation. Five-day animal survival increased from 0% in the control to 60% in the 6 mg/kg group, 100% in the 10 mg/kg group, and 80% in the 15 mg/kg group. Lazaroid protected the hepatocytes from damage during preservation, and enhanced energy charge and hepatic blood flow after reperfusion. Histological alterations were significantly less severe in the lazaroid-treated groups. The area of necrotic hepatocytes decreased from 43.7 +/- 17.7 in the control to 13.5 +/- 3.0 in the lazaroid 10 mg/kg group. These results indicate that lazaroid U-74389G has potential for improvement of clinical liver preservation.

Lidocaine action and conformational changes in cytoskeletal protein network in human red blood cells

The mechanism of action of lidocaine, which is commonly used clinically as a local anesthetic, was studied in human red blood cells. The influx of [14C]lidocaine through the cell membrane induced reversible transformation of human red blood cells from discocytes to stomatocytes. This change in shape depended on the lidocaine concentration and required both ATP and carbonic anhydrase. The lidocaine-induced shape change occurred as a result of spectrin aggregation, which altered the intracellular environment of the human red blood cells, mediated by carbonic anhydrase and activation of vacuolar type H(+)-ATPase (V-ATPase). Lidocaine controlled the influx of 22Na into the human red blood cells in a concentration-dependent manner. When incubated in media containing 6-chloro-9-[(4-diethylamino)-1-methyl-butyl]amino-2-methoxyacridine (mepacrine), an inhibitor of Na+ channels, human red blood cells changed shape from discocytes to stomatocytes and the intracellular pH decreased. This phenomenon was very similar to the shape change induced by lidocaine. These results suggest that the mode of action of lidocaine is related to a conformational change in the cytoskeletal protein network.

[Development of apoptosis induced by whole-body irradiation in murine liver]

Apoptosis is known to be induced by radiation. However, the correlation between radiation-induced apoptosis and radiation injury in tumors in vivo has been unclear. In this paper, we report the study of apoptosis induced by whole-body irradiation using an immunohistochemical technique to detect DNA fragmentation in murine liver. A dose of 7 Gy was employed as LD50/30. DNA fragmentation was observed 30 min after radiation, and it peaked between 1 and 6 hours. DNA fragmentation could be detected 48 hours after radiation in capillary endothelium. This study was able to reveal the development of radiation-induced apoptosis in the liver by detecting DNA fragmentation in situ.