Enhanced anaerobic digestion performance and sludge filterability by membrane microaeration for anaerobic membrane bioreactor application

Slow dissolution/hydrolysis of insoluble/macromolecular organics and poor sludge filterability restrict the application potential of anaerobic membrane bioreactor (AnMBR). Bubble-free membrane microaeration was firstly proposed to overcome these obstacles in this study. The batch anaerobic digestion tests feeding insoluble starch and soluble peptone with and without microaeration showed that microaeration led to a 65.7-144.8% increase in methane production and increased critical flux of microfiltration membrane via driving the formation of large sludge flocs and the resultant improvement of sludge settleability. The metagenomic and bioinformatic analyses showed that microaeration significantly enriched the functional genes and bacteria for polysaccharide and protein hydrolysis, microaeration showed little negative effects on the functional genes involved in anaerobic metabolisms, and substrate transfer from starch to peptone significantly affected the functional genes and microbial community. This study demonstrates the dual synergism of microaeration to enhance the dissolution/hydrolysis/acidification of insoluble/macromolecular organics and sludge filterability for AnMBR application.

TRAIL and Celastrol Combinational Treatment Suppresses Proliferation, Migration, and Invasion of Human Glioblastoma Cells via Targeting Wnt/β-catenin Signaling Pathway

OBJECTIVE

To investigate the mechanistic basis for the anti-proliferation and anti-invasion effect of tumor necrosis factor-related apoptosis-induced ligand (TRAIL) and celastrol combination treatment (TCCT) in glioblastoma cells.

METHODS

Cell counting kit-8 was used to detect the effects of different concentrations of celastrol (0-16 µmol/L) and TRAIL (0-500 ng/mL) on the cell viability of glioblastoma cells. U87 cells were randomly divided into 4 groups, namely control, TRAIL (TRAIL 100 ng/mL), Cel (celastrol 0.5 µmol/L) and TCCT (TRAIL 100 ng/mL+ celastrol 0.5 µmol/L). Cell proliferation, migration, and invasion were detected by colony formation, wound healing, and Transwell assays, respectively. Quantitative reverse transcription polymerase chain reaction and Western blotting were performed to assess the levels of epithelial-mesenchymal transition (EMT) markers (zona occludens, N-cadherin, vimentin, zinc finger E-box-binding homeobox, Slug, and β-catenin). Wnt pathway was activated by lithium chloride (LiCl, 20 mol/L) and the mechanism for action of TCCT was explored.

RESULTS

Celastrol and TRAIL synergistically inhibited the proliferation, migration, invasion, and EMT of U87 cells (P<0.01). TCCT up-regulated the expression of GSK-3β and down-regulated the expression of β-catenin and its associated proteins (P<0.05 or P<0.01), including c-Myc, Cyclin-D1, and matrix metalloproteinase (MMP)-2. In addition, LiCl, an activator of the Wnt signaling pathway, restored the inhibitory effects of TCCT on the expression of β-catenin and its downstream genes, as well as the migration and invasion of glioblastoma cells (P<0.05 or P<0.01).

CONCLUSIONS

Celastrol and TRAIL can synergistically suppress glioblastoma cell migration, invasion, and EMT, potentially through inhibition of Wnt/β-catenin pathway. This underlies a novel mechanism of action for TCCT as an effective therapy for glioblastoma.

[A case report of ocular monkeypox]

A 35-year-old male patient arrived at the clinic, reporting a persistent issue of his right eye being difficult to open for the past three weeks. Alongside this, he had been experiencing a gradual development of lesions around the eye. Notably, about a month prior to the onset of these symptoms, the patient had engaged in unprotected intercourse with a male partner. The initial manifestation was a papule near the eye, which then rapidly progressed. Laboratory analysis of samples taken from the lesions confirmed the presence of monkeypox through polymerase chain reaction testing. Furthermore, this patient received positive diagnoses for both HIV and syphilis infections. Notably, his absolute CD4 count was measured at an extremely low level of 2 cells/μl.(This article was published ahead of print on the official website of Chinese Journal of Ophthalmology on September 18, 2023).

Effect of ferrate pre-oxidation on algae-laden water ultrafiltration: Attenuating membrane fouling and decreasing formation potential of disinfection byproducts

Effect of ferrate [Fe(VI)] pre-oxidation on improving FeCl₃/ultrafiltration (UF) of algae-laden source water was investigated. Fe(VI) disrupted algae cells and the in situ formed ferric (hydr)oxides aggregated with cell debris. Particle size and zeta potential of algae increased by 20% and 55% on average, respectively, after treatment with 0.02 mM of Fe(VI). These variations facilitated the formation of algae-ferric floc. Fe(VI) degraded algal extracellular organic matter into lower molecular weight products (fulvic-like and humic-like substances). Membrane flux, reversible membrane resistance (R_r) and irreversible membrane resistance (R_ir) were improved by 51%, 61%, and 52% in Fe(VI) (0.02 mM)/FeCl₃/UF treatment group compared with FeCl₃/UF treatment after three filtration cycles. Fe(VI)/FeCl₃/UF removed more than 10% ~ 34% of the dissolved organic compounds (DOC) and 6% ~ 17% of the total nitrogen (TN) compared with FeCl₃/UF. Due to the enhanced removal of DOC and TN, formation potential of 12 kinds of carbonaceous-disinfection byproducts (C-DBPs) and 7 kinds of nitrogenous-disinfection byproducts (N-DBPs) decreased by 32.5% and 22.5%, respectively. Fe(VI) pre-oxidant was effective for alleviating membrane fouling and reducing formation potential of DBPs in algal laden water treatment.

[The effect of surgical treatment on Meniere's disease]

Objective:To compare functional outcomes after different surgical procedures in treatment of patients with Meniere's disease. Method:Patients with Meniere's disease were categorized into different groups mainly based on pure-tone average and functional level scale. Individualized surgical procedure was provided including endolymphatic sac shunt or decompression (ELSS), vestibular neurectomy (VN), labyrinthectomy (LC), semicircular canals plugging (SCP) and endolymphatic duct blockage (EDB). Result:Vertigo control rate of Grade A and B was 78.4% in patients with ELSS, 100.0% with VN, 100.0% with LC, 87.0% with SCP and 86.4% with EDB, respectively. Hearing was preserved with ELSS, VN and EDB postoperatively (P>0.05). But there was a significant hearing loss after SCP (P<0.05). Postoperatively, the QOL score improved significantly in each group (P<0.01). There were CSF leakage in 4 cases, temporary facial paralysis in 1 case, intracranial infection in 1 case, and abdominal hematoma in 5 cases in VN group after surgeries. None of the above complications occurred in other groups. Conclusion:Surgical Treatment choice for patients with Meniere's disease depends on several factors. The functional outcomes after different surgeries are generally satisfying. Residual hearing can be preserved effectively and the quality of life can be improved greatly. VN can effectively eradicate vertigo and preserve residual hearing, however, there is still a risk of some complications with this procedure. As for VN, retrolabyrinthine approach is more advantageous compared with retrosigmoid sinus approach.

[The progress of topical drug delivery to the inner ear for the inhibition of inflammation and fibrosis following cochlear implantation]

Nowadays, more than 300 000 deaf people around the world benefit from cochlea implantation. With the extension of cochlear implantation indications, it has become a research focus for how to apply the anti-inflammatory and anti-fibrotic drugs safely and effectively to better retain residual hearing, as well as to protect hair cells and the spiral ganglion cells from apoptosis. Due to the blood-labyrinth barrier, perioperative systemic steroids are often unable to achieve satisfactory drug concentration in the inner ear. Also, given that higher doses of steroids will cause more serious side effects and sometimes steroids are strictly limited to apply on some patients with certain diseases, the attention has been attracted on topical drug delivery to the inner ear. In this review, the methods of topical drug delivery to the inner ear are divided into four categories: transtympanic injection of liquid solutions, tympanic implantation of drug delivery systems, intracochlear injection and modified implant electrode. The results in each category and up to date progress are reviewed.

High recycling efficiency and elemental sulfur purity achieved in a biofilm formed membrane filtration reactor

Elemental sulfur (S⁰) is always produced during bio-denitrification and desulfurization process, but the S⁰ yield and purification quality are too low. Till now, no feasible approach has been carried out to efficiently recover S⁰. In this study, we report the S⁰ generation and recovery by a newly designed, compact, biofilm formed membrane filtration reactor (BfMFR), where S⁰ was generated within a Thauera sp. strain HDD-formed biofilm on membrane surface, and then timely separated from the biofilm through membrane filtration. The high S⁰ generation efficiency (98% in average) was stably maintained under the operation conditions with the influent acetate, nitrate and sulfide concentration of 115, 120 and 100 mg/L, respectively, an initial inoculum volume of approximate 2.4 × 10⁸ cells, and a membrane pore size of 0.45 μm. Under this condition, the sulfide loading approached 62.5 kg/m³·d, one of the highest compared with the previous reports, demonstrating an efficient sulfide removal and S⁰ generation capacity. Particular important, a solid analysis of the effluent revealed that the recovered S⁰ was adulterated with barely microorganisms, extracellular polymeric substances (EPSs), or inorganic chemicals, indicating a fairly high S⁰ recovery purity. Membrane biofilm analysis revealed that 80.7% of the generated S⁰ was accomplished within 45-80 μm of biofilm from the membrane surface and while, the complete membrane fouling due to bacteria and EPSs was generally observed after 14-16 days. The in situ generation and timely separation of S⁰ from the bacterial group by BfMFR, effectively avoids the sulfur circulation (S^2- to S⁰, S⁰ to SO₄^2-, SO₄^2- to HS^-) and guarantees the high S⁰ recovery efficiency and purity, is considered as a feasible approach for S⁰ recovery from sulfide- and nitrate-contaminated wastewater.

Agonists for G-protein-coupled receptor 84 (GPR84) alter cellular morphology and motility but do not induce pro-inflammatory responses in microglia

Background

Several G-protein-coupled receptors (GPCRs) have been shown to be important signaling mediators between neurons and glia. In our previous screening for identification of nerve injury-associated GPCRs, G-protein-coupled receptor 84 (GPR84) mRNA showed the highest up-regulation by microglia after nerve injury. GPR84 is a pro-inflammatory receptor of macrophages in a neuropathic pain mouse model, yet its function in resident microglia in the central nervous system is poorly understood.

Methods

We used endogenous, natural, and surrogate agonists for GPR84 (capric acid, embelin, and 6-OAU, respectively) and examined their effect on mouse primary cultured microglia in vitro.

Results

6-n-Octylaminouracil (6-OAU), embelin, and capric acid rapidly induced membrane ruffling and motility in cultured microglia obtained from C57BL/6 mice, although these agonists failed to promote microglial pro-inflammatory cytokine expression. Concomitantly, 6-OAU suppressed forskolin-induced increase of cAMP in cultured microglia. Pertussis toxin, an inhibitor of Gi-coupled signaling, completely suppressed 6-OAU-induced microglial membrane ruffling and motility. In contrast, no 6-OAU-induced microglial membrane ruffling and motility was observed in microglia from DBA/2 mice, a mouse strain that does not express functional GPR84 protein due to endogenous nonsense mutation of the GPR84 gene.

Conclusions

GPR84 mediated signaling causes microglial motility and membrane ruffling but does not promote pro-inflammatory responses. As GPR84 is a known receptor for medium-chain fatty acids, those released from damaged brain cells may be involved in the enhancement of microglial motility through GPR84 after neuronal injury.

[Historical evolution and frontier of endolymphatic sac surgery for treatment of Ménière's disease]

Surgical treatment could be necessary for patients with intractable Ménière's disease.Endolymphatic sac surgery is a favorable option as it could preserve patient's hearing and vestibular function.The overall vertigo control rate after the surgery was about 80%.Endolymphatic sac surgery includes several variations,namely sac shunting,sac drainage,and sac decompression.Although their establishment and development have experienced a long tortuous process,the theoretical basis and clinical efficacy of the surgery remain controversial.Meanwhile,new findings and surgical innovation keep emerging.This article introduces the historical evolution and reviews the frontier of endolymphatic sac surgery for treatment of Ménière's disease.

Maternal citrulline supplementation prevents prenatal dexamethasone-induced programmed hypertension

Glucocorticoids are administered to premature infants to accelerate pulmonary maturation. In experimental model, prenatal dexamethasone (DEX) results in reduced nephron number and adulthood hypertension. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), can cause oxidative stress and is involved in the development of hypertension. L-citrulline can be converted to l-arginine (the substrate for NOS) in the body. Thus we intended to determine if maternal L-citrulline therapy can prevent prenatal DEX-induced programmed hypertension by restoration ADMA/nitric oxide (NO) balance, alterations of renin-angiotensin system (RAS) and sodium transporters, and epigenetic regulation by histone deacetylases (HDACs). Male offspring were assigned to four groups: control, pregnancy rats received intraperitoneal DEX (0.2 mg/kg body weight) daily on gestational days 15 and 16 (DEX), pregnancy rats received 0.25% L-citrulline in drinking water during the entire pregnancy and lactation period (CIT), and DEX + CIT. We found DEX group developed hypertension at 16 weeks of age, which was prevented by maternal L-citrulline therapy. Prenatal DEX exposure increased plasma ADMA concentrations and reduced renal NO production. However, L-citrulline reduced plasma ADMA level and increased renal level of NO in DEX + CIT group. Next, prenatal DEX-induced programmed hypertension is related to increased mRNA expression of angiotensin and angiotensin II type 1 receptor, and class I HDACs in the kidney. Prenatal DEX exposure increased renal protein abundance of Na(+)/Cl(-) cotransporter (NCC), which was prevented by L-citrulline therapy. The beneficial effects of L-citrulline therapy include restoration of ADMA/NO balance and alteration of NCC, to prevent the prenatal DEX-induced programmed hypertension.

[Effect of naringenin on learning and memory ability on model rats with Alzheimer disease]

OBJECTIVE

To investigate the effects of naringenin on the learning and memory ability of Alzheimer disease (AD) rats.

METHODS

30 male SD rats were randomly divided into control group (sham operation group), model group and naringenin group. AD model was established by injecting strepoztocin (3 mg/kg) twice into each of two intracerebroventriculas. Naringenin group were given intragastric administration of naringenin once a day for 3 weeks and the other two groups were given intragadtric administration of normal saline with the same dosage and time period. After 3 weeks, learning and memory ability in all the three groups were analyzed by Morris water maze, the activity of superoxide dismutase(SOD) and the content of malondialdehyde (MDA) of the rats' brain tissue was detected by chemical colorimetric determination. Observed the expressions of Abeta42 and Abeta40 by immunohistochemical method. The expression and degree of phosphorylation of tau protein was assayed by western blotting.

RESULTS

1. Compared with the sham operation group, the mean escape latency of the model group was significantly prolonged (P < 0.05) and the time that rats were in the platform quadrant was significantly shortened (P < 0.0.5). On the contrary, compared with the model group, the mean escape latency of naringenin group was significantly shortened (P < 0.05) and the time that rats were in the platform quadrant was significantly extended (P < 0.005). 2. The level of MDA in the model group, compared with the sham operation group group, was significantly increased (P < 0.05). Whereas, that of naringenin group, compared with the model group, was significantly decreased compared with the sham operation group (P < 0.05). The activity of SOD in the naringenin group was significantly increased comparing with the model group (P < 0.05). 3. The expressions of Abeta40 and Abeta42 in model group were obviously up-regulated. Instead, the expressions of Abeta40 and Abeta42 in the naringenin group were significantly down regulated. 4. There was no significant difference in the expression of tau protein among each groups. Nevertheless, the phosphorylation of tau protein in the model group was significantly enhanced than that in the control group (P < 0.05), and the phosphorylation of tau protein in the naringenin group was significantly reduced than that in the model group (P < 0.05).

CONCLUSION

Naringenin can improve learning and memory ability of model rats with Alzheimer disease through the approach of oxidative stress.

Measuring the activity of heterotrophic microorganism in membrane bioreactor for drinking water treatment

In order to quantify the activity of heterotrophic microorganism in membrane bioreactor (MBR) for drinking water treatment, biomass respiration potential (BRP) test and 2,3,5-triphenyl tetrazolium chloride-dehydrogenase activity (TTC-DHA) test were introduced and modified. A sludge concentration ratio of 5:1, incubation time of 2h, an incubation temperature that was close to the real operational temperature, and using a mixture of main AOC components as the substrate were adopted as the optimum parameters for determination of DHA in drinking water MBR. A remarkable consistency among BDOC removal, BRP and DHA for assessing biological performance in different MBRs was achieved. Moreover, a significant correlation between the BRP and DHA results of different MBRs was obtained. However, the TTC-DHA test was expected to be inaccurate for quantifying the biomass activity in membrane adsorption bioreactor (MABR), while the BRP test turned out to be still feasible in that case.

Berberine and total base from rhizoma coptis chinensis attenuate brain injury in an aluminum-induced rat model of neurodegenerative disease

OBJECTIVE

To investigate the protective effects of the total base from rhizoma coptis chinensis (CTB) and berberine (Ber) on neurodegeneration induced by aluminum overload in rats.

METHODS

The study took place in the Department of Pharmacology, Chongqing Medical University, Chongqing, China, between February 2005 and May 2007. Wistar rats were divided into control group, model group, Ber-treated group, CTB (55 mg/kg and 110 mg/kg)-treated group, and nimodipine-treated group (n=20). A rat brain damage model was established via intragastric administration of 400 mg/kg element aluminum once a day, 5 days a week for 12 weeks. The CTB, Ber, and nimodipine were intragastrically administered 4 hours after each aluminum administration for 12 weeks. The morphological changes of the neurons of the rat hippocampus and the changes of rat learning and memory functions were observed. The superoxide dismutase (SOD), choline acetyltransferase (ChAT), acetylcholinesterase (AchE), and monoamine oxidase-B (MAO-B) activities and malondialdehyde (MDA) content, as well as the MAO-B expression in the rat brain were examined.

RESULTS

The CTB, Ber, and nimodipine significantly improved the learning and memory ability impairment and hippocampal neuronal death. The CTB, Ber, and nimodipine also significantly blunted the decrease of SOD and ChAT activities, and the increase of MDA content, AchE activities, and MAO-B expressions and activity in the aluminum-overload rats.

CONCLUSION

The CTB and Ber have protective effects on neurodegeneration induced by aluminum overload. The CTB (110 mg/kg) has more powerful neuroprotection than Ber.

Clinical features and outcome of appendicitis in children younger than three years of age

BACKGROUND

Acute appendicitis is the most common surgically amenable cause of acute abdominal pain in children. We analyzed our past experience of appendectomies in children and present the clinical characteristics of appendicitis in children younger than 3 years of age. A better understanding of appendicitis in early childhood would allow us to achieve an earlier diagnosis.

METHODS

A group of 475 children from 4 months to 15 years of age who underwent appendectomy for appendicitis was studied over a 5-year period from July 1994 to June 1999. Excluding cases with negative pathological findings (n = 34), they were divided into 2 age groups: group I (< or = 3 years old) and group II (> 3 years old). Medical records were reviewed and comparisons between clinical findings, laboratory data, pathology findings, and complications were made.

RESULTS

Of 441 cases enrolled in our study, 24 (5.4%) were 3 years of age or younger. Of all children older than 3 years of age, 32 (7.1%) had negative pathological findings compared to children younger than 3 years of age (7.7%). The duration of symptoms prior to diagnosis in group I was 3.6 days compared to group II at 2.0 days. Children from group I frequently showed a higher incidence of fever (90% vs. 53.4%), abdominal distention (50% vs. 9.8%), perforation (50% vs. 40.1%), and missed first impression (29% vs. 2.4%) than those from group II. Children of group I also had a higher complication rate (41.7% vs. 11.5%).

CONCLUSIONS

In early childhood the symptoms and signs of appendicitis usually are nonspecific. There is a longer duration before diagnosis, more instances of fever and abdominal distention, less right lower quadrant pain, less local tenderness and rebounding pain, and no obturator sign. Close observation and on-going evaluation of patients are essential.

Common variable immunodeficiency with mosaic trisomy 8: report of one case

This case study reported a 17-year-old female of common variable immunodeficiency (CVID) associated with bronchiectasis, pernicious anemia and mosaic trisomy 8. Clinically this patient presented with recurrent sinopulmonary infections, intractable diarrhea, macrocytic anemia, and primary amenorrhea. Immunological tests showed pan-hypogammaglobulinemia and a decrease of peripheral blood B cells (4%) and CD4+ cells (25%). Lymphoproliferative responses to mitogen (PHA) and specific antigen (BCG) were profoundly impaired in the patient in comparison to those in control. Production of interleukin 4 (IL-4) and gamma interferon (IFN-gamma) in the in vitro lymphoproliferation was also profoundly depressed. Pernicious anemia demonstrated by larger MCV (112.9 fl) and hyper-segmental granulocytes on peripheral blood smear responded to parental administration of vitamin B12. Interestingly, she had a mosaic trisomy 8 in peripheral blood mononuclear cells but normal 46XX karyotype in the bone marrow cells. To our knowledge, this is the first case of CVID associated with mosaic trisomy 8 reported in the literature. As the case exemplifies, CVID should be considered when the physicians evaluate the patient presenting with recurrent sinopulmonary infections, diarrhea, malnutrition, and pernicious anemia. It requires further study to explore whether the genes in the chromosome 8 are linked to CVID.

Flexible bronchoscopic diagnosis of airway injuries after intubation in children

BACKGROUND

Airway intubation injuries occur frequently but are often neglected because of spontaneous regression. Although most airway injuries that result from intubation resolve without sequelae, severe complications can develop even when initial symptoms of upper airway obstruction are absent. This retrospective study assessed the clinical features, flexible bronchoscopic findings, and clinical outcomes in children with airway intubation injuries.

METHODS

From February 1998 to February 1999, 90 children underwent flexible bronchoscopic examination in our hospital. Fifteen of these patients (6 girls, 9 boys; age range, 1 mo to 5 yr; mean, 21.1 +/- 24.4 mo) were noted to have intubation injuries.

RESULTS

The average time for symptoms to emerge after extubation was 1.8 days (range, 0-14 days). The airway intubation injuries diagnosed by flexible bronchoscopy were subglottic stenosis in seven patients, vocal cord granulation in four, supraglottic granulation in two, subglottic web in two, bronchial granulation in two, glottic stenosis in one, and tracheal stenosis in one; two cases were discovered incidentally during postoperative follow-up. Four patients had undergone repeated intubation and eventually required tracheostomy.

CONCLUSIONS

The results of this study indicate that flexible bronchoscopy is a simple, safe, and useful technique for the diagnosis and follow-up of airway intubation injury. It should be performed on all patients who have symptoms of upper airway obstruction after extubation as well as those who have undergone long-term or emergency intubation.

Infantile hypertrophic pyloric stenosis presenting as pseudo-Bartter's syndrome and seizures: report of one case

We report a hypertrophic pyloric stenosis case with an unusual initial presentation of seizures and Bartter's syndrome like symptoms. This case suffered from vomiting, diarrhea and poor appetite for several days, and seizures developed after these symptoms. From laboratory tests, hypochloremic and hypokalemic metabolic alkalosis associated with hyperreninemia, hyperaldosteronism and normal blood pressure were noted. Pseudo-Bartter's syndrome was diagnosed through these clinical and laboratory tests. Although the first abdominal echo was negative, we still speculated about the peculiar symptoms of vomiting and it's relationship to pseudo-Bartter's syndrome. After all, we found the hypertrophic pyloric stenosis through an upper gastrointestinal series. From these experiences, we postulated that it's very important to put the hypertrophic pyloric stenosis into the differential diagnosis of pseudo-Batter's syndrome.

Purification and functional characterization of MerD. A coregulator of the mercury resistance operon in gram-negative bacteria

Mercury resistance operons (mer) from transposons Tn21, Tn501, and plasmid pDU1358 are highly homologous and inducible with Hg2+. The regulatory gene merR is transcribed from one promoter, which is divergently oriented from the promoter for the other mer genes. MerR, the product of the regulatory gene, negatively regulates its own expression as well as the expression of the other genes. MerR activates transcription of the operon in the presence of inducing concentrations of Hg2+. The most promoter distal gene, merD, which is cotranscribed with the structural genes, down regulates the mer operon. A frame-shift mutation in merD, created by deletion of 3 bp and an insertion of a 16 bp sequence upstream of the major inverted repeats present at the 3' end of the merD sequence, resulted in increased synthesis of the structural gene transcript and higher level of resistance to Hg2+ by a factor of about 2. MerD protein was over-produced using a T7 expression system. The overproduced protein was present in the pellet fraction, when cell lysates were centrifuged at a low speed. Approximately 80% pure MerD protein was recovered from the pellet fraction by extracting with a buffer solution containing 5 M urea. The purified protein migrated as a 13,500 molecular weight protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the N-terminal amino acid sequence corresponded to that deduced from the DNA sequence of merD. MerD bound specifically with the mer promoter sequence. DNase I footprinting experiments identified a common mer operator sequence for MerR and MerD.

Relationship between secreted urokinase plasminogen activator activity and metastatic potential in murine B16 cells transfected with human urokinase sense and antisense genes

Murine melanoma B16-F1 cells of low metastatic potential were transfected with the human gene for the prepro form of urokinase in an SV40 expression vector (plasmid pSV2-uPA), and cells expressing high amounts of the human urokinase gene product were selected for by an enzyme-linked immunosorbent assay specific for human high molecular weight urokinase. Southern analysis showed one of the cell lines (clone 7) had incorporated 150 copies of the pSV2-uPA plasmid into its genomic DNA. The human urokinase synthesized by the pSV2-uPA-transfected murine B16 cells was found to be glycosylated and did not bind to the murine cell surface urokinase receptor sites. In an in vivo assay that measures metastasis from a primary tumor (spontaneous metastatic assay), clone 7 cells showed an increased ability to metastasize (12 of 12 mice showed metastatic tumors), while control cells showed a lower ability to metastasize (only 2 of 11 mice showed metastatic tumors). In a second in vivo assay, which measures only the steps of the metastatic migration process during which tumor cells extravasate from the blood and then grow into pulmonary tumors (lung colonization assay), a significant multifold increase in the ability to form lung tumors was shown by the high human urokinase-secreting B16-F1 cells. In B16-F10 cells incorporating an antisense sequence to preprourokinase (plasmid pSV1-ASuPA-265) and secreting significantly decreased amounts of murine urokinase, a corresponding significant decrease in lung colonization was observed. These results provide direct experimental support for a role of secreted (non-surface-bound) urokinase in the colonization steps of the metastatic process. Furthermore, the data indicate that the higher lung colonization ability of the B16-F10 line than of the B16-F1 line is primarily based on the quantitative differences in their abilities to produce urokinase.

[A study on injured policemen in dental field]

In 1989, there were 8893 injured policemen by various demonstrations. This injury ratio (8893/130,000) is about 3 times higher than other occupations. Of them, 2869 (31%) were treated at National Police Hospital, and 13% of which were facial injuries. The most common etiologic factor of facial injuries was demonstrations by Univ. students (89.2%), and 93.9% of the victims were injured by thrown stone.