A matrix metalloproteinase expressed on the surface of invasive tumour cells

Gelatinase A (type-IV collagenase; M(r) 72,000) is produced by tumour stroma cells and is believed to be crucial for their invasion and metastasis, acting by degrading extracellular matrix macro-molecules such as type IV collagen. An inactive precursor of gelatinase A (pro-gelatinase A) is secreted and activated in invasive tumour tissue as a result of proteolysis which is mediated by a fraction of tumour cell membrane that is sensitive to metalloproteinase inhibitors. Here we report the cloning of the complementary DNA encoding a new matrix metalloproteinase with a potential transmembrane domain. Expression of the gene product on the cell surface induces specific activation of pro-gelatinase A in vitro and enhances cellular invasion of the reconstituted basement membrane. Tumour cells of invasive lung carcinomas, which contain activated forms of gelatinase A, were found to express the transcript and the gene product. The new metalloproteinase may thus trigger invasion by tumour cells by activating pro-gelatinase A on the tumour cell surface.

Mode of invasion, bleomycin sensitivity, and clinical course in squamous cell carcinoma of the oral cavity

Forty patients with squamous cell carcinoma of the oral cavity were treated with bleomycin prior to undergoing surgery. The degree of the clinical effect of bleomycin and the postoperative clinical course of each case were estimated from the viewpoint of correlation with the mode of invasion. A strong correlation was found among the mode of invasion, bleomycin sensitivity, and clinical course. A slight effect of bleomycin and poor prognosis existed in the group with a diffuse invasion of mode of invasion, while the greatest effect of bleomycin and good clinical course were achieved in the group with a well-defined tumor-host borderline.

Indoleamine 2,3-dioxygenase is a novel prognostic indicator for endometrial cancer

Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-catabolising enzyme inducing immune tolerance. The present study aimed to investigate IDO expression and its prognostic significance in endometrial cancer. Indoleamine 2,3-dioxygenase expression in endometrial cancer tissues (n = 80) was immunohistochemically scored as four groups (IDO-, 1+, 2+, and 3+). The high IDO expression (IDO2+ or 3+) in tumour cells was found in 37 (46.3%) of the 80 cases, and was positively correlated with surgical stage, myometrial invasion, lymph-vascular space involvement, and lymph node metastasis, but not with the histological grade. Patients with high IDO expression had significantly impaired overall survival and progression-free survival (PFS) (P = 0.002 and P = 0.001, respectively) compared to patients with no or weak expression of IDO (IDO- or 1+). The 5-year PFS for IDO-/1+, 2+, and 3+ were 97.7, 72.9, and 36.4%, respectively. Even in patients with early-stage disease (International Federation of Gynecology and Obstetrics I/II, n = 64), the PFS for IDO2+/3+ was significantly poor (P = 0.001) compared to that for IDO-/1+. On multivariate analysis, IDO expression was an independent prognostic factor for PFS (P = 0.020). These results indicated that the high IDO expression was involved in the progression of endometrial cancer and correlated with the impaired clinical outcome, suggesting that IDO is a novel and reliable prognostic indicator for endometrial cancer.

Mode of invasion and lymph node metastasis in squamous cell carcinoma of the oral cavity

The relationship between the mode of tumor invasion in the tumor-host borderline and the frequency of regional lymph node metastasis was investigated in squamous cell carcinoma of the oral cavity. Cases with grades 1-3 mode of invasion classified by modified Jacobsson criteria showed a low frequency of metastasis (10/72, 13.9%), while those cases with grade 4 mode of invasion, which consisted of grade 4C (cord-like type) and grade 4D (diffuse type) showed a high frequency of metastasis (4C:11/18,61.1%; 4D :9/12,75.0%; total 20/30,66.7%). Moreover, the number of metastatic nodes in each case of mode of invasion ranged from 1 to 3 in grades 1-3, from 1 to 5 in grade 4C, and from 1 to 7 in grade 4D . The presence of metastasis indicated a poorer prognosis than did the absence of the mode of invasion in each grade, especially in grades 4C and 4D .

Sustained release of basic fibroblast growth factor and angiogenesis in a novel covalently crosslinked gel of heparin and alginate

The construction of organs by tissue engineering and regenerative engineering, using an artificial extracellular matrix, is an innovative method that is expected to replace artificial organs and organ transplantation. We have produced an artificial extracellular matrix of alginate and demonstrated that the matrix stimulated the regeneration of skin, nerve, and bone. In this report, the new matrix, which consists of heparin and alginate covalently crosslinked with ethylenediamine, was produced to stabilize and control the release of growth factors. Heparin content of the new matrix was confirmed by toluidine blue absorption, elementary analysis, and Fourier transform infrared spectrum. In vitro experiments showed that the new matrix significantly suppressed the initial burst of basic fibroblast growth factor, which is a representative member of heparin-binding growth factors, and released biologically active basic fibroblast growth factor for 1 month under physiological conditions. Obvious cellular infiltration and angiogenesis were shown to occur in the new matrix which was implanted subcutaneously in the dorsal area of rat with 1 microg of basic fibroblast growth factor for 2 weeks. This new matrix may be useful for not only the construction of transplantable blood vessels of small diameter, but also the induction of angiogenesis in regenerated skin constructed by tissue engineering.

Ingested arsenic and internal cancer: a historical cohort study followed for 33 years

A historical cohort study was conducted to investigate the long-term effect of exposure to ingested arsenic. The 454 residents who had been identified in a list made in 1959 were followed until 1992. They lived in an arsenic-polluted area, called Namiki-cho, Nakajo-machi, in Niigata Prefecture, Japan, and used well water containing inorganic arsenic. The exposure period was estimated to be about 5 years (1955-1959). Death certificates for the people who died between 1959 and 1992 were examined, and a total of 113 of the 454 residents were estimated to have drunk well water containing a high dose of arsenic (> or = 1 ppm). The standardized mortality rate ratios of these 113 residents were 15.69 for lung cancer (observed/expected = 8/0.51; 95% confidence interval (CI) 7.38-31.02) and 31.18 for urinary tract cancer (observed/expected = 3/0.10; 95% CI 8.62-91.75). Cox's proportional hazard analyses demonstrated that the hazard ratios of the highest exposure level group (> or = 1 ppm) versus the background exposure level group (0.001 ppm) were 1.74 (95% CI 1.10-2.74) for all deaths and 4.82 (95% CI 2.09-11.14) for all cancers. The analysis according to the skin signs of chronic arsenicism in 1959 showed that they were useful risk indicators for subsequent cancer development. In the development of lung cancer, there was evidence of synergism between arsenic intake and smoking habit.

Efficacy of primary treatment with immunoglobulin plus ciclosporin for prevention of coronary artery abnormalities in patients with Kawasaki disease predicted to be at increased risk of non-response to intravenous immunoglobulin (KAICA): a randomised controlled, open-label, blinded-endpoints, phase 3 trial

BACKGROUND

Genetic studies have indicated possible involvement of the upregulated calcium-nuclear factor of activated T cells pathway in the pathogenesis of Kawasaki disease. We aimed to assess safety and efficacy of ciclosporin, an immunosuppressant targeting this pathway, for protection of patients with Kawasaki disease against coronary artery abnormalities.

METHODS

We did a randomised, open-label, blinded endpoints trial involving 22 hospitals in Japan between May 29, 2014, and Dec 27, 2016. Eligible patients predicted to be at higher risk for intravenous immunoglobulin (IVIG) resistance were randomly assigned to IVIG plus ciclosporin (5 mg/kg per day for 5 days; study treatment) or IVIG (conventional treatment) groups, stratified by risk score, age, and sex. The primary endpoint was incidence of coronary artery abnormalities using Japanese criteria during the 12-week trial, assessed in participants who received at least one dose of study drug and who visited the study institution at least once during treatment. This trial is registered to Center for Clinical Trials, Japan Medical Association, number JMA-IIA00174.

FINDINGS

We enrolled 175 participants. One patient withdrew consent after enrolment and was excluded and one patient (in the study treatment group) was excluded from analysis because of lost echocardiography data. Incidence of coronary artery abnormalities was lower in the study treatment group than in the conventional treatment group (12 [14%] of 86 patients vs 27 [31%] of 87 patients; risk ratio 0·46; 95% CI 0·25-0·86; p=0·010). No difference was found in the incidence of adverse events between the groups (9% vs 7%; p=0·78).

INTERPRETATION

Combined primary therapy with IVIG and ciclosporin was safe and effective for favourable coronary artery outcomes in Kawasaki disease patients who were predicted to be unresponsive to IVIG.

FUNDING

Japan Agency for Medical Research and Development (grant CCT-B-2503).

Generation of a highly pathogenic avian influenza A virus from an avirulent field isolate by passaging in chickens

Highly virulent avian influenza viruses can arise from avirulent strains maintained in poultry, but evidence to support their generation from viruses in wild birds is lacking. The most likely mechanism for the acquisition of virulence by benign avian viruses is the introduction of mutations by error-prone RNA polymerase, followed by the selection of virulent viruses. To investigate whether this mechanism could apply to wild waterfowl, we studied an avirulent wild-swan virus that replicates poorly in chickens. After 24 consecutive passages by air sac inoculation, followed by five passages in chicken brain, the avirulent virus became highly pathogenic in chickens, producing a 100% mortality rate. Sequence analysis at the hemmaglutinin cleavage site of the original isolate revealed a typical avirulence type of sequence, R-E-T-R, which progressed incrementally to a typical virulence type of sequence, R-R-K-K-R, during repeated passages in chickens. These results demonstrate that avirulent viruses maintained in wild waterfowl in nature and bearing the consensus avirulence type sequence R-E-T-R have the potential to become highly pathogenic while circulating in chickens.

Bacteriologic features and antimicrobial susceptibility in isolates from orofacial odontogenic infections

OBJECTIVE

The aim of this study was to obtain information for an effective antimicrobial therapy against orofacial odontogenic infections; such information was obtained from recent bacteriologic features and antimicrobial susceptibility data.

STUDY DESIGN

The bacteriology and antimicrobial susceptibility of major pathogens in 163 patients with orofacial odontogenic infections to 7 antibiotics was examined.

RESULTS

Mixed infection of strict anaerobes with facultative anaerobes (especially viridans streptococci) was observed most often in dentoalveolar infections, periodontitis, and pericoronitis. Penicillin (penicillin G) was effective against almost all pathogens, although it did not work well against beta-lactamase-positive Prevotella. Cefmetazole was effective against all test pathogens. Erythromycin was ineffective against viridans streptococci and most Fusobacterium. Clindamycin exerted a strong antimicrobial activity on anaerobes. Minocycline was effective against almost all the test pathogens. The antimicrobial activity of levofloxacin against viridans streptococci was not strong.

CONCLUSIONS

An antibiotic that carries out antimicrobial activity against both viridans streptococci and oral anaerobes should be suitable for treatment of dentoalveolar infection, periodontitis, and pericoronitis. Penicillin remains effective as an antimicrobial against most major pathogens in orofacial odontogenic infections. Cefmetazole, clindamycin, and minocycline may be effective against most pathogens, including penicillin-unsusceptible bacteria.

Immunohistochemical study of tumour angiogenesis in oral squamous cell carcinoma

To assess the clinical significance of angiogenesis in oral squamous cell carcinoma (SCC), we examined vessel density immunohistochemically in 44 primary oral SCCs using the JC-70A antibody which reacts specifically with vascular endothelial cells. In addition, the expression of vascular endothelial growth factor (VEGF) and its receptors, KDR, Flt-1 and Flt-4 in oral SCCs was examined in relation to the vessel density and lymph node metastasis. There was no association of vessel density with tumour site, T-category (tumour size), degree of differentiation or cervical lymph node metastasis, except that the vessel density of carcinomas with a well-defined tumour-stromal boundary was higher than that of diffusely invasive carcinomas. The intensity of VEGF expression correlated with lymph node metastasis (P < 0.01), but not with vessel density. The expression of KDR and Flt-1 did not correlate with vessel density and lymph node metastasis. However, the vessel density in Flt-4-positive carcinomas was higher than that in Flt-4-negative carcinomas (P < 0.05), and expression of Flt-4 most significantly correlated with lymph node metastasis (P < 0.001). These results suggest that the expression of VEGF or Flt-4 rather than vessel density may be a predictor of lymph node metastasis in oral SCC.

Positive affect among nursing home residents with Alzheimer's dementia: the effect of recreational activity

The experience of positive emotions is an integral component of quality of life. Research suggests that cognitive deficits in persons with dementia may impede their ability to generate pleasurable moments and hence decrease their positive affect. Therefore, structured recreation activities may have the potential to significantly improve resident affect. However, differences in affect between ordinary time and recreation time are not well known. The present study used previously published structured-observation instruments to measure affect and behaviour among 35 dementia residents at two nursing homes in Japan during ordinary time and during recreation time. A total of 3,854 one-minute observations were coded. Dementia residents expressed happiness over seven times more often during recreation time than during ordinary time. Over 60% of ordinary time was solitary, with 65.72% of all observed affect being 'Null Affect'. A total of 43.75% of residents expressed happiness only during recreation time. In addition 48.9% of all behaviour during 'Ordinary Time' was coded as 'Null Behaviour', which indicated that the resident was sitting and doing nothing. Findings indicate that recreation time is significantly higher in positive affect than ordinary time and that virtually all residents benefited from recreation.

Angiotensin II type 1 receptor expression in ovarian cancer and its correlation with tumour angiogenesis and patient survival

Angiotensin II, a main effector peptide in the renin–angiotensin system, acts as a growth-promoting and angiogenic factor via type 1 angiotensin II receptors (AT₁R). We have recently demonstrated that angiotensin II enhanced tumour cell invasion and vascular endothelial growth factor (VEGF) secretion via AT₁R in ovarian cancer cell lines in vitro. The aim of the present study was to determine whether AT₁R expression in ovarian cancer is correlated with clinicopathological parameters, angiogenic factors and patient survival. Immunohistochemical staining for AT₁R, VEGF, CD34 and proliferating cell nuclear antigen (PCNA) were analysed in ovarian cancer tissues (n=67). Intratumour microvessel density (MVD) was analysed by counting the CD34-positive endothelial cells. Type 1 angiotensin II receptors were expressed in 85% of the cases examined, of which 55% were strongly positive. Type 1 angiotensin II receptors expression was positively correlated with VEGF expression intensity and MVD, but not with histological subtype, grade, FIGO stage or PCNA labelling index. In patients who had positive staining for AT₁R, the overall survival and progression-free survival were significantly poor (P=0.041 and 0.017, respectively) as compared to those in patients who had negative staining for AT₁R, although VEGF, but not AT₁R, was an independent prognostic factor on multivariate analysis. These results demonstrated that AT₁R correlated with tumour angiogenesis and poor patient outcome in ovarian cancer, suggesting its clinical potential for a novel molecular target in strategies for ovarian cancer treatment.

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.

Antimicrobial susceptibility of 800 anaerobic isolates from patients with dentoalveolar infection to 13 oral antibiotics

INTRODUCTION

The aim of this study was to determine the current antimicrobial susceptibility of the principle anaerobic pathogens involved in dentoalveolar infection, to 13 oral antibiotics, and to assess the value of each antibiotic in the management of the infection.

METHODS

A total of 800 isolates from patients with dentoalveolar infection (Prevotella species, Fusobacterium species, Porphyromonas species and Peptostreptococcus micros) were tested for their susceptibility to amoxicillin, amoxicillin/clavulanate, cefaclor, cefuroxime, cefcapene, cefdinir, erythromycin, azithromycin, telithromycin, minocycline, levofloxacin, clindamycin, and metronidazole using an agar dilution method.

RESULTS

Although the majority of Fusobacterium strains were resistant to erythromycin, azithromycin, and telithromycin, the remaining antibiotics demonstrated a high level of antimicrobial activity. P. micros and Porphyromonas species exhibited high susceptibility to all antibiotics tested in this study. In the case of Prevotella species, resistance to amoxicillin occurred in 34% of isolates and all of these resistant strains were found to produce beta-lactamase. Susceptibility of Prevotella strains to cefaclor, cefuroxime, cefcapene, cefdinir, erythromycin, azithromycin, and minocycline was found to correlate with amoxicillin susceptibility. Amoxicillin/clavulanate, telithromycin, clindamycin, and metronidazole exhibited high antimicrobial activity even against amoxicillin-resistant strains of Prevotella species.

CONCLUSION

Amoxicillin would still be advocated therefore as being a suitable first-line agent, while reduced susceptibility of Prevotella strains remains a matter of concern with penicillins. Amoxicillin/clavulanate, clindamycin, and metronidazole are useful alternatives in combating the anaerobic bacteria involved in dentoalveolar infection.

Mechanical properties of collagen fascicles from the rabbit patellar tendon

Tensile and viscoelastic properties of collagen fascicles of approximately 300 microns in diameter, which were obtained from rabbit patellar tendons, were studied using a newly designed micro-tensile tester. Their cross-sectional areas were determined with a video dimension analyzer combined with a CCD camera and a low magnification microscope. There were no statistically significant differences in tensile properties among the fascicles obtained from six medial-to-lateral locations of the patellar tendon. Tangent modulus, tensile strength, and strain at failure of the fascicles determined at about 1.5 percent/s strain rate were 216 +/- 68 MPa, 17.2 +/- 4.1 MPa, and 10.9 +/- 1.6 percent (mean +/- S.D.), respectively. These properties were much different from those of bulk patellar tendons; for example, the tensile strength and strain at failure of these fascicles were 42 percent and 179 percent of those of bulk tendons, respectively. Tangent modulus and tensile strength of collagen fascicles determined at 1 percent/s strain rate were 35 percent larger than those at 0.01 percent/s. The strain at failure was independent of strain rate. Relaxation tests showed that the reduction of stress was approximately 25 percent at 300 seconds. These stress relaxation behavior and strain rate effects of collagen fascicles differed greatly from those of bulk tendons. The differences in tensile and viscoelastic properties between fascicles and bulk tendons may be attributable to ground substances, mechanical interaction between fascicles, and the difference of crimp structure of collagen fibrils.

Characterization of experimental ischemic brain edema utilizing proton nuclear magnetic resonance imaging

Correlations between T1 and T2 relaxation times and water and electrolyte content in the normal and ischemic rat and gerbil brains were studied by means of both nuclear magnetic resonance (NMR) spectroscopic and imaging methods. In the spectroscopic experiment on excised rat brains, T1 was linearly dependent on tissue water content and T2 was prolonged in edematous tissue to a greater extent than expected by an increase in water content, showing that T2 possesses a greater sensitivity for edema identification and localization. Changes in Na+ and K+ content of the tissue mattered little in the prolongation of relaxation times. Serial NMR imaging of gerbil brains insulted with permanent hemispheric ischemia offered early lesion detection in T1- and especially T2-weighted images (detection as soon as 30 min after insult). The progressive nature of lesions was also imaged. Calculated T1 and T2 relaxation times in regions of interest correlated excellently with tissue water content (r = 0.892 and 0.744 for T1 and T2, respectively). As a result, detection of cerebral ischemia utilizing NMR imaging was strongly dependent on a change in tissue water content. The different nature of T1 and T2 relaxation times was also observed.

Accelerated blood clearance of PEGylated liposomes containing doxorubicin upon repeated administration to dogs

The accelerated blood clearance phenomenon involving anti-PEG IgM production has been recognized as an important issue for the design and development of PEGylated liposomes. Here, we show that empty PEGylated liposomes and Doxil, PEGylated liposomes containing doxorubicin, both caused anti-PEG IgM production and thereby a rapid clearance of the second and/or third dose of Doxil in Beagle dogs in a lipid-dose, inverse-dependent manner. It appears that the pharmacokinetic profile of the second and third administration of Doxil reflected the presence of anti-PEG IgM circulating in the blood. Doxil plus an excess amount of empty PEGylated liposomes rather enhanced the production of anti-PEG IgM compared to Doxil of the same doxorubicin dose. During sequential administration, increasing the lipid dose of Doxil in each dose by the addition of empty PEGylated liposomes strongly attenuated the magnitude of the ABC phenomenon during the effectuation phase of a second and third dose of Doxil. Our results suggest that the pre-clinical study of anti-cancer drug-containing PEGylated liposomes with dogs must be carefully designed and performed with monitoring of the anti-PEG IgM and liposomal drugs circulating in the blood.

Living related liver transplantation in children

We reviewed 37 living related liver transplantations (LRLT) performed by our department during the last 27 months on children with end-stage liver disease. The patients were 15 boys and 22 girls aged 7 months to 15 years with biliary atresia (27), cryptogenic cirrhosis (3), Budd-Chiari syndrome (2), progressive intrahepatic cholestasis (2), protoporphyria (1), Wilson's disease (1), and fulminant hepatitis (1). The donors were 14 fathers and 23 mothers. Grafts were made from the left lateral segment (19), left lateral segment with partial S4 (11), left lobe (6), and right lobe (1). After graft harvesting all donors resumed normal liver function and normal life. The recipient underwent total hepatectomy with preservation of the inferior vena cava. FK506 and low-dose steroids were used for immunosuppression. The survival rate was 90% (27/30) in elective cases and 57% (4/7) in emergency cases. Six recipients had functioning grafts but died of extrahepatic complications. Hepatic vein stenosis occurred in 3 cases at 3 months after LRLT and was successfully treated by balloon dilatation. Portal vein stenosis occurred in 1 case at 8 months after LRLT and was also safely dilated. We incurred no hepatic artery thrombosis after introducing microsurgery techniques. Among 12 viral, 5 bacterial, and 3 fungal postoperative infections, 1 Candida pneumonia and 1 EBV-associated lymphoma were lethal. Three patients with ABO-blood group compatible grafts and one with an incompatible graft developed acute rejection, which was controlled in evey case by steroid bolus and/or increasing the dose of FK506. There were no definite episodes of rejection in ABO-identical cases. Children with moderate growth retardation (> or = -1.5 SD of normal growth) caught up in growth soon after LRLT, but those with severe retardation (<-1.5 SD) were slow to attain age-normal height. Appropriate timing, meticulous surgical procedures, and comprehensive management of complications are crucial for successful outcome with LRLT. LRLT is a promising option for alleviating the shortage of livers for pediatric transplantation and may be regarded as an independent modality to supplement cadaver donation.

Activation of the precursor of human stromelysin 2 and its interactions with other matrix metalloproteinases

Matrix metalloproteinases (MMP) are synthesized as inactive zymogens (proMMP) and subsequently activated by many factors to degrade the extracellular matrix (ECM). In the present study, we have examined the intermolecular activation mechanisms of proMMP by MMP-10 (stromelysin 2). ProMMP-10 was purified from the culture media of OSC-20 human oral squamous carcinoma cells stimulated with 12-O-tetradecanoylphorbol 13-acetate. The final products are partially activated (approximately 38% of the full activity) during the purification steps and contain proMMP-10 of Mr 56,000 with minor protein bands of Mr 47,000, 24,000 and 22,000. The zymogen is activated by 4-aminophenylmercuric acetate and processed to the active forms of Mr 47,000 and 24,000. The NH2-terminal sequence of the 47,000- and 24,000-Mr species is Phe82-Ser-Ser-Phe-Pro-Gly, which is identical to that of stromelysin 2. ProMMP-9 (progelatinase B) is activated by MMP-10 to its full activity and processed to the low-Mr species of Mr 81,000, 65,000, 57,000 and 55,000, the former two of which show proteolytic activity on a gelatin zymography. The NH2-terminal sequence analysis indicates that the 81,000-, 65,000- and 57,000-M, species have the identical sequence of Phe88-Gln-Thr-Phe-Glu-Gly, suggesting the cleavage of the Arg87-Phe88 peptide bond for activation and both NH2-terminal and COOH-terminal truncation in the 65,000- and 57,000-Mr forms. MMP-10 also activates proMMP-7 (promatrilysin) up to about 60% of the full activity and generates the same active species of Mr 19,000 as that obtained by activation with 4-aminophenylmercuric acetate. Incubation of proMMP-2 (progelatinase A) or proMMP-3 with MMP-10 does not result in activation of these proMMP. These results indicate that in addition to the previously reported activation of proMMP-1 (tissue procollagenase) and proMMP-8 (neutrophil procollagenase), MMP-10 can also activate proMMP-9 and proMMP-7, and suggest the possibility that MMP-10 may replace a role of MMP-3 in the ECM degradation in concert with other MMP under various pathological conditions.

Functional mapping of the human colour centre with echo-planar magnetic resonance imaging

Clinical studies of cerebral achromatopsia have suggested a colour centre in the human fusiform gyrus. By using functional magnetic resonance imaging, we examined whether the fusiform gyrus shows activity correlated with the perception of colour. We tested three stimulus conditions in which the subject maintained fixation: (i) a circular array of six coloured circles; (ii) the same as (i) except that each circle is equiluminant grey with its colour counterpart; and (iii) the same as (i) plus a clockwise shift of circles to neighbouring positions every 1 s. After termination of the stimulus, the subject perceived an after-image of circles with complementary colours in (i), but not in (iii). In condition (i), we found a focal signal increase in the posterior part of the fusiform gyrus. In condition (ii), the activation in the same locus during the stimulation period was weaker than that in (i). In condition (iii), the signal intensity after termination of the stimulus was weaker than that in (i). The colour effect and after-effect on activation of the fusiform gyrus observed here suggest its critical role in human colour perception.

Temporomandibular joint morphology and disc position in skeletal class III patients

INTRODUCTION

The purpose of this study was to investigate the relationship between temporomandibular joint (TMJ) morphology, including discal tissue and clinical symptoms in class III dentofacial deformity patients.

MATERIAL AND METHODS

Forty-four patients were examined with lateral, frontal and axial cephalograms. They were divided into two groups, consisting of a class III symmetry and a class III asymmetry group. By using magnetic resonance imaging the 88 joints could be classified into four types on the basis of disc position and shape: anteriorly displaced disc, anterior type, fully-covered type and posterior type. Furthermore, TMJ morphology was measured tomographically in the sagittal plane.

RESULTS

Anteriorly displaced discs in the asymmetry group (56.8%) occurred significantly more frequently than in the symmetry group (18.2%; p <0.05). TMJ symptoms (clicking, crepitus, closed lock, pain) were seen in 17/44 joints (38.6%) of the symmetry and 24/44 joints (54.5%) of the asymmetry group, for a total of 41/88 joints (46.6%). There were no differences in joint space ratio and condyle ratio. However, the fossa ratio on the deviation side was significantly higher than on the nondeviation side in the asymmetry group (p<0.05).

CONCLUSION

The incidence of internal derangement in asymmetrical class III patients is higher than in symmetrical mandibular prognathism, and this difference is associated with a difference in TMJ morphology of both sides.

Factors affecting the occurrence of bacteremia associated with tooth extraction

This study examined the factors that affect the occurrence of bacteremia associated with tooth extraction and the kinds of bacteria causing this bacteremia. Bacteremia was found in 132 (72.1%) of 183 patients who had one or more teeth extracted for various reasons. Bacteremia occurred more frequently when teeth were extracted because of inflammatory dental diseases. The occurrence of bacteremia also increased with the number of teeth extracted and the age of the patients. When the volume of blood lost during surgery was > 50 ml and the time required for the operation exceeded 100 min, the occurrence of bacteremia was also higher. Anaerobes were isolated from 104 (78.8%) of the 132 cases of bacteremia. Of the 187 isolates obtained, three (1.6%) were aerobes, 51 (27.3%) were facultative anaerobes (including microaerophils), and 133 (71.1%) were anaerobes. Among facultative anaerobes and microaerophils, the most frequently isolated bacterial genera were Lactobacillus (n = 15), Streptococcus (n = 13), and Staphylococcus (n = 12); and among anaerobes, Eubacterium (n = 40), Peptostreptococcus (n = 40), and Propionibacterium (n = 20).

Past administration of beta-lactam antibiotics and increase in the emergence of beta-lactamase-producing bacteria in patients with orofacial odontogenic infections

OBJECTIVE

The purpose of this study was to determine the current status of beta-lactamase-producing bacteria in orofacial odontogenic infections.

STUDY DESIGN

Microbiologic data regarding purulent exudate from 111 cases with orofacial odontogenic infections were analyzed in relation to the past administration of beta-lactams.

RESULTS

beta-lactamase-producing bacteria were isolated more frequently from the beta-lactam-administered group (38.5%) than from the beta-lactam-nonadministered group (10.9%; P <.005), and they were isolated more frequently as the duration of administration increased. The predominant bacteria isolated included Prevotella (the most frequent isolate), viridans streptococci, Peptostreptococcus, and Fusobacterium, and 7.1% of total isolates produced beta-lactamase. Penicillin and cefazolin worked well with beta-lactamase-nonproducing Prevotella but were remarkably affected by beta-lactamase-producing Prevotella. Cefmetazole, sulbactam/cefoperazone, and imipenem worked well against both types of Prevotella.

CONCLUSIONS

beta-lactams are still suitable for the first antimicrobial therapy in the treatment of these infections. However, because past beta-lactam administration increases the emergence of beta-lactamase-producing bacteria, beta-lactamase-stable antibiotics should be prescribed to patients with unresolved infections who have received beta-lactams.

Cloning of a human gene potentially encoding a novel matrix metalloproteinase having a C-terminal transmembrane domain

Matrix metalloproteinases (MMPs) play key roles in tissue remodeling during physiological and pathological processes by degrading various extracellular matrix (ECM) components. Although nine distinct MMPs have been characterized by cDNA cloning, there are thought to be more corresponding to the complexity of the ECM. MMP genes expressed in human tissues and cell lines were analyzed by the polymerase chain reaction (PCR) using degenerate primers that corresponded to the conserved amino acid (aa) sequences of the MMPs. One isolated complementary DNA (cDNA) fragment had sequence homology to the reported MMPs, but was otherwise unique. A human placenta cDNA library (Clontech) was screened using the fragment as a probe and a 3.4-kb cDNA fragment containing a long open reading frame (potentially encoding 582 aa) was isolated. The putative gene product had a common domain structure and the conserved sequence of a MMP, but it had a unique transmembrane (TM)-like structure at the C terminus. It should, therefore, be an TM protein, whereas all the other reported MMPs are secretory proteins. Thus, the gene is thought to be the first of a new subclass of MMPs whose products are potentially expressed on the cell surface.