IFN-γ from lymphocytes induces PD-L1 expression and promotes progression of ovarian cancer

BACKGROUND

PD-L1 (programmed cell death 1 ligand 1) on tumour cells suppresses host immunity through binding to its receptor PD-1 on lymphocytes, and promotes peritoneal dissemination in mouse models of ovarian cancer. However, how PD-L1 expression is regulated in ovarian cancer microenvironment remains unclear.

METHODS

The number of CD8-positive lymphocytes and PD-L1 expression in tumour cells was assessed in ovarian cancer clinical samples. PD-L1 expression and tumour progression in mouse models under conditions of altering IFN-γ signals was assessed.

RESULTS

The number of CD8-positive cells in cancer stroma was very high in peritoneally disseminated tumours, and was strongly correlated to PD-L1 expression on the tumour cells (P<0.001). In mouse models, depleting IFNGR1 (interferon-γ receptor 1) resulted in lower level of PD-L1 expression in tumour cells, increased the number of tumour-infiltrating CD8-positive lymphocytes, inhibition of peritoneal disseminated tumour growth and longer survival (P=0.02). The injection of IFN-γ into subcutaneous tumours induced PD-L1 expression and promoted tumour growth, and PD-L1 depletion completely abrogated tumour growth caused by IFN-γ injection (P=0.01).

CONCLUSIONS

Interferon-γ secreted by CD8-positive lymphocytes upregulates PD-L1 on ovarian cancer cells and promotes tumour growth. The lymphocyte infiltration and the IFN-γ status may be the key to effective anti-PD-1 or anti-PD-L1 therapy in ovarian cancer.

Arthroscopy of the distal radioulnar joint

Wrist arthroscopy is now widely indicated for diagnosis and treatment of acute or chronic wrist pain, especially for triangular fibrocartilage complex (TFCC) lesions, as a gold standard. In most cases radiocarpal and midcarpal arthroscopy was performed, while DRUJ arthroscopy has been rarely performed because of its difficulties. Recent anatomic and biomechanical studies demonstrated that the radioulnar ligament (RUL), which is the proximal component of the TFCC facing to the DRUJ, is the primary stabilizer of the distal radioulnar joint (DRUJ). Rupture of the radioulnar ligament (RUL) at the fovea area, where it is the main attaching portion to the ulna and is the isometric point during forearm rotation as the rotation axis passes, is responsible for DRUJ instability. Although physical examination and imaging diagnosis may indicate a foveal detachment of the TFCC, DRUJ arthroscopy is potential for visualizing the RUL at the fovea. Role of DRUJ arthroscopy should be more important not only for diagnosis of rupture of the RUL but also for decision making of treatment option for RUL tear. DRUJ arthroscopy also demonstrates the joint surface of both the sigmoid notch and ulnar head, and the proximal surface of the TFCC.

Activity of retreatment with sorafenib for metastatic renal cell carcinoma

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Background: Treatment options for metastatic renal cell carcinoma (mRCC) have increased. Complete remission is, however, rarely seen and patients are treated with multiple sequential therapies. We assessed clinical activity of sorafenib rechallenge after progressing on other therapies.

Methods: Patients with mRCC who received a second course of sorafenib therapy after failure of prior sorafenib and other agents were retrospectively identified. RECIST-defined objective response rate and progression-free survival (PFS) and toxicity were analyzed.

Results: Fourteen patients with mRCC who were retreated with sorafenib were identified and twelve patients were assessable for this study. 92% were male. Median age at first systemic therapy was 63 years. Prior nephrectomy was performed in 92% of patients. 42% of patients had favorable or intermediate risk, 17% poor, and the rest not available per MSKCC criteria. Eighty-three percent of patients were treated with other agents before initial sorafenib therapy, including 75% interferon-alpha (IFN-alpha), 50% interleukin-2 (IL-2), and 17% sunitinib. First sorafenib therapy began a median of 9.0 months after the diagnosis of mRCC and produced a clinical benefit (PR + SD) rate of 75% and a median PFS of 5.0 months. 67% of patients discontinued initial sorafenib for disease progression and 33% for adverse events. Interval between discontinuation of initial sorafenib and rechallenge was a median of 7.6 months. During the intervening period, 50% of patients were treated with sunitinib, 33% with everolimus, 25% with VEGFR1 vaccine, and others. Clinical benefit rate of 67% and a median PFS of 4.3 months were obtained on sorafenib rechallenge. There was no significant difference in outcome to sorafenib rechallenge based on duration between sorafenib treatments or number or type of intervening treatments. No new severe toxicity was observed during rechallenge.

Conclusions: Sorafenib rechallenge has potential to achieve clinical benefits, is well-tolerated, and may be considered after multiple sequential therapies in select mRCC patients.

No significant financial relationships to disclose.

Anchorage-independent cell growth signature identifies tumors with metastatic potential

The oncogenic phenotype is complex, resulting from the accumulation of multiple somatic mutations that lead to the deregulation of growth regulatory and cell fate controlling activities and pathways. The ability to dissect this complexity, so as to reveal discrete aspects of the biology underlying the oncogenic phenotype, is critical to understanding the various mechanisms of disease as well as to reveal opportunities for novel therapeutic strategies. Previous work has characterized the process of anchorage-independent growth of cancer cells in vitro as a key aspect of the tumor phenotype, particularly with respect to metastatic potential. Nevertheless, it remains a major challenge to translate these cell biology findings into the context of human tumors. We previously used DNA microarray assays to develop expression signatures, which have the capacity to identify subtle distinctions in biological states and can be used to connect in vitro and in vivo states. Here we describe the development of a signature of anchorage-independent growth, show that the signature exhibits characteristics of deregulated mitochondrial function and then demonstrate that the signature identifies human tumors with the potential for metastasis.

MHC class I and II expression in juvenile dermatomyositis skeletal muscle

OBJECTIVE

To assess MHC I and II expressions in muscle fibres of juvenile dermatomyositis (JDM) and compare with the expression in polymyositis (PM), dermatomyositis (DM) and dystrophy.

PATIENTS AND METHODS

Forty-eight JDM patients and 17 controls (8 PM, 5 DM and 4 dystrophy) were studied. The mean age at disease onset was 7.1+/-3.0 years and the mean duration of weakness before biopsy was 9.4+/-12.9 months. Routinehistochemistry and immunohistochemistry (StreptABComplex/HRP) for MHC I and II (Dakopatts) were performed on serial frozen muscle sections in all patients. Mann-Whitney, Kruskal Wallis, chi-square and Fisher's exact statistical methods were used.

RESULTS

MHC I expression was positive in 47 (97.9%) JDM cases. This expression was observed independent of time of disease, corticotherapy previous to muscle biopsy and to the grading of inflammation observed in clinical, laboratorial and histological parameters. The expression of MHC I was similar on JDM, PM and DM, and lower in dystrophy. On the other hand, MHC II expression was positive in just 28.2% of JDM cases and was correlated to histological features as inflammatory infiltrate, increased connective tissue and VAS for global degree of abnormality (p<0.05). MHC II expression was similar in DM/PM and lower in JDM and dystrophy, and it was based on the frequency of positive staining rather than to the degree of the MCH II expression.

CONCLUSIONS

MHC I expression in muscle fibres is a premature and late marker of JDM patient independent to corticotherapy, and MHC II expression was lower in JDM than in PM and DM.

Increased cyclooxygenase-2 expression is correlated with suppressed antitumor immunity in cervical adenocarcinomas

Cyclooxygenase-2 (COX-2) inhibition suppressed the growth of various tumors. The augmentation of antitumor immunity by increasing cytotoxic lymphocytes may be an important mechanism for COX-2 inhibition. Among cervical cancers, adenocarcinomas present more aggressive behavior and overexpressed COX-2. The expression of COX-2 and the CD8+ lymphocyte infiltrations were evaluated in this study by immunohistochemistry. We studied COX-2 expression and CD8+ lymphocyte infiltration in 55 women with cervical adenocarcinomas. COX-2 expression and tumor stromal CD8+ lymphocytes were evaluated by semiquantified methods. Tumor intraepithelial lymphocytes were counted under microscopic field of x200. Correlations between these data and other clinicopathologic features were investigated. Thirty-seven out of 55 (67.3%) cervical adenocarcinomas significantly expressed COX-2. Patients who died within 5 years showed higher percentage of COX-2 expression than survivors (100% vs 58.1%, P < 0.05). Victims also showed lesser intraepithelial CD8+ lymphocyte counts than survived patients (3.4 vs 26.4, P < 0.05). COX-2 expression and tumor intraepithelial lymphocyte count were reversely correlated with each other (correlation index: -0.38, P < 0.01). Up-regulated COX-2 expression and lesser tumor intraepithelial CD8+ lymphocyte count are poor prognostic indicators for cervical adenocarcinoma patients. COX-2 may play an important role in the suppression of host antitumor immunity in cervical adenocarcinomas.

Regulation of Chk2 gene expression in lymphoid malignancies: involvement of epigenetic mechanisms in Hodgkin's lymphoma cell lines

The tumor suppressor Chk2 kinase plays crucial roles in regulating cell-cycle checkpoints and apoptosis following DNA damage. We investigated the expression levels of the genes encoding Chk2 and several cell-cycle regulators in nine cell lines from lymphoid malignancies, including three Hodgkin's lymphoma (HL) lines. We found that all HL cell lines exhibited a drastic reduction in Chk2 expression without any apparent mutation of the Chk2 gene. However, expression of Chk2 in HL cells was restored following treatment with the histone deacetylase inhibitors trichostatin A (TsA) and sodium butyrate (SB), or with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5Aza-dC). Chromatin-immunoprecipitation (Chip) assays revealed that treatment of HL cells with TsA, SB or 5Aza-dC resulted in increased levels of acetylated histones H3 and H4, and decreased levels of dimethylated H3 lysine 9 at the Chk2 promoter. These results indicate that expression of the Chk2 gene is downregulated in HL cells via epigenetic mechanisms.

Impact of Neuronavigation and Image-Guided Extensive Resection for Adult Patients with Supratentorial Malignant Astrocytomas: A Single-Institution Retrospective Study

Neuronavigation has become an effective therapeutic modality and is used routinely for intra-axial tumor removal. This retrospective study was conducted to evaluate the clinical impact of neuronavigation and image-guided extensive resection for adult patients with supratentorial malignant astrocytomas. Between 1990 and 2002, 76 adult patients with pathologically confirmed malignant astrocytomas underwent craniotomy and removal of the tumors at the Toyama Medical and Pharmaceutical University Hospital. Of these 76 patients, 42 were treated using neuronavigation with conventional microneurosurgery and the other 34 were treated with conventional microneurosurgery alone. Postoperative early MRI with contrast enhancement was done, and gross total resection was defined as the complete absence of residual tumor. Survival time was analyzed with the Kaplan-Meier method. Prognostic factors were obtained from the Cox proportional hazards model. In univariate analysis, age (< 65), grade 3, preoperative KPS (>/= 80), use of neuronavigation, and gross total resection were significantly associated with longer survival. However, when the data were submitted to multivariate analysis, grade 3, preoperative KPS (>/= 80), and gross total resection were independent prognostic factors. The median survival periods of patients receiving gross total resection (vs. partial resection) and neuronavigation (vs. no neuronavigation) were 16 (vs. 9) months and 16 (vs. 10) months, respectively. The percentage of a gross total resection was significantly higher in the neuronavigation group compared to that in the no-navigation group (64.3 % vs. 38.2 %, p < 0.05). Neurological deterioration occurred in 4 of 42 (9.5 %) and in 6 of 34 (17.6 %) patients after surgery with neuronavigation and surgery without neuronavigation, respectively, although this difference was not statistically significant. Our results showed that neuronavigation increases the radicality in the resection of malignant astrocytomas and is objectively useful for improving survival time.

Livaditis' circular myotomy does not decrease anastomotic leak rates and induces deleterious changes in anastomotic healing

Considering that Livaditis' myotomy is still accepted as a good method for lengthening the esophagus to allow primary repair of long-gap esophageal atresia, the aim of this experimental study was to verify if this procedure decreases the incidence of leaks in anastomoses performed under severe tension. In addition, it was verified whether the myotomy promotes any morphological or biochemical change in the healing esophageal anastomosis. Sixty small dogs were submitted to a cervicotomy and resection of an esophageal segment (8.0 - 10.0 cm) resulting in an anastomosis under severe tension. The animals were divided into two groups (control group: only anastomosis; experimental group: anastomosis plus circular myotomy in the proximal esophageal segment). The animals were sacrificed on the 14th postoperative day, submitted to autopsy, and were evaluated as to the presence of leaks. Twelve scars of each group were collected for histological, histomorphometric (evaluation of scar thickness), electrophoretic and immunoblotting studies of collagen (total collagen and types of collagen determinations). Leak rates were the same in both groups. Histologic examination showed that the scar at the anastomosis was formed by fibrous tissue, without mucosa or muscular tissue. In the myotomy animals, a decreased number of newly formed small vessels was noted in comparison to control animals, and morphometric analysis showed that in the myotomy animals the anastomotic scar was thinner than in the control animals. Biochemical analysis of scars demonstrated that myotomy promoted a decrease in the soluble collagen content in comparison with the control animals and no alteration in the content of insoluble collagen. The electrophoretic separation of the types of collagen and characterization by immunoblotting demonstrated the presence of collagen types I, III, and V, and the quantification by densitometry of the bands showed a reduction in collagen type V (present in the blood vessels) in the myotomy animals in comparison to controls. This result is in accordance with the histological observation of a decrease in newly formed blood vessels. Circular myotomy does not decrease the possibility of anastomotic leaks, in addition to promoting deleterious changes in anastomotic healing.

Asymptomatic pyuria in diabetic women

The aim of the present study was to determine the prevalence of and the host factors for asymptomatic pyuria (ASP) in women with type 2 diabetes. The study included 179 type 2 diabetic women and consecutive 455 non-diabetic women attending as out-patients in 1996. Patients with symptoms of a urinary tract infection were excluded. ASP was defined as the presence of more than 10 leukocytes/high-power field in a random urine sample. Diabetic women more often had ASP than non-diabetic women (27.9 vs. 15.8%, P<0.001). The prevalence of ASP was significantly increased in patients with a duration of diabetes exceeding 15 years (0 approximately 4 years; 20.3%, 5 approximately 9 years; 24.3%, 10 approximately 14 years; 23.8%, and > or =15 years; 46.3%). No differences were evident in HbA(1C) between diabetic patients without ASP and those with ASP. Diabetic women with ASP more often had diabetic retinopathy, neuropathy, nephropathy, cerebrovascular disease, ischemic heart disease, and hyperlipidemia than those without ASP. However, no statistically significant differences were evident in the prevalence of hypertension, constipation, or dementia. As the degree of neuropathy increases, it is accompanied by an increasing prevalence of ASP (none, 21.4%; blunt tendon reflexes, 24.5%; symptomatic, 50.0%; and gangrene, 66.6%). The prevalence of ASP was significantly increased in the patients with proliferative diabetic retinopathy (none, 23.2%; background, 29.4%; pre-proliferative, 18.2%; and proliferative, 50.0%). As the degree of nephropathy increases, it is accompanied by an increasing prevalence of ASP (none, 20.0%; microalbuminuria, 31.9%; macroalbuminuria, 37.0%; and renal failure, 60.0%). Thus, the prevalence of ASP is increased in women with diabetes and increased with longer duration of diabetes but was not affected by glucose control. The incidence of ASP increases significantly as diabetic microangiopathy becomes severer.

Right sylvian fissure subarachnoid hemorrhage has electrocardiographic consequences

BACKGROUND AND PURPOSE

Abnormal ECG changes are frequently observed in patients with subarachnoid hemorrhage (SAH). Recently, evidence has been obtained that right insular cortex mediates sympathetic cardiovascular effects. We therefore assessed the laterality and location of SAH dominance in inducing cardiovascular changes as measured by ECG, blood pressure, and heart rate.

METHODS

After exclusion of 11 SAH patients who died within 1 month after onset, we studied 118 consecutive patients. Data were obtained from records of blood pressure and pulse on admission. Abnormal ECG changes were determined from ECGs on admission and almost 1 month later. From brain CT scans performed immediately after admission, the amount of SAH in each of the 8 cisterns and fissures was measured semiquantitatively.

RESULTS

Twenty-six patients had abnormal changes on admission ECG, while 92 patients did not. Systolic blood pressure, diastolic blood pressure, and the amounts of blood in the left ambient cistern, left suprasellar cistern, quadrigeminal cistern, right ambient cistern, right suprasellar cistern, right sylvian fissure, and the set of all cisterns were significantly greater in the group with ECG change than in the group without ECG change. Multivariate logistic regression analysis with stepwise method indicated that systolic blood pressure >160 mm Hg (P=0.0006) and the amounts of SAH in the quadrigeminal cistern (P=0.022) and right sylvian fissure (P=0.0019) were independently associated with abnormal ECG change.

CONCLUSIONS

Cardiac consequences are possible in patients with massive right sylvian fissure SAH or when systolic blood pressure is >160 mm Hg.

Helicobacter pylori infection and the development of gastric cancer

BACKGROUND

Although many studies have found an association between Helicobacter pylori infection and the development of gastric cancer, many aspects of this relation remain uncertain.

METHODS

We prospectively studied 1526 Japanese patients who had duodenal ulcers, gastric ulcers, gastric hyperplasia, or nonulcer dyspepsia at the time of enrollment; 1246 had H. pylori infection and 280 did not. The mean follow-up was 7.8 years (range, 1.0 to 10.6). Patients underwent endoscopy with biopsy at enrollment and then between one and three years after enrollment. H. pylori infection was assessed by histologic examination, serologic testing, and rapid urease tests and was defined by a positive result on any of these tests.

RESULTS

Gastric cancers developed in 36 (2.9 percent) of the infected and none of the uninfected patients. There were 23 intestinal-type and 13 diffuse-type cancers. Among the patients with H. pylori infection, those with severe gastric atrophy, corpus-predominant gastritis, and intestinal metaplasia were at significantly higher risk for gastric cancer. We detected gastric cancers in 21 (4.7 percent) of the 445 patients with nonulcer dyspepsia, 10 (3.4 percent) of the 297 with gastric ulcers, 5 (2.2 percent) of the 229 with gastric hyperplastic polyps, and none of the 275 with duodenal ulcers.

CONCLUSIONS

Gastric cancer develops in persons infected with H. pylori but not in uninfected persons. Those with histologic findings of severe gastric atrophy, corpus-predominant gastritis, or intestinal metaplasia are at increased risk. Persons with H. pylori infection and nonulcer dyspepsia, gastric ulcers, or gastric hyperplastic polyps are also at risk, but those with duodenal ulcers are not.

[A four-year prospective study on the influence of serum elevated lipoprotein (a) concentration on ischemic heart disease and cerebral infarction in elderly patients with type 2 diabetes]

To clarify the influence of elevated serum lipoprotein (a) (Lp(a)) concentration on ischemic heart disease (IHD) and the perforating artery occlusion type of cerebral infarction (CI) in elderly patients with type 2 diabetes, we measured the serum levels of Lp(a) of type 2 diabetic patients (n = 158, 81 men and 77 women). The group was followed up prospectively for 4 years and the incidence of IHD or CI was monitored. The diagnosis of CI was confirmed by computed tomography and that of IHD, which includes myocardial infarction and angina pectoris, was diagnosed by electrocardiogram and blood chemistry examination, Lp(a) concentrations of 20 mg/dl or more were identified as elevated Lp(a) levels and Lp(a) concentrations of less than 20 mg/dl were identified as normal Lp(a) levels. A Kaplan-Meier survival analysis (log-rank test) assessed the time to event rate stratified by an Lp(a) cutoff point of 20 mg/dl. The predictive value for CI or IHD events was assessed by multiple logistic regression analysis. The probability of IHD events was significantly higher in the elevated Lp(a) group than in the normal Lp(a) group without a history of IHD but was similar in the two groups for those patients with a history of IHD. There was no significant difference between the elevated Lp(a) group and the normal Lp(a) group with regard to CI events in patients without a history of CI and with a history of CI. On multiple logistic regression analysis, Lp(a), hyperlipidemia and a history of IHD were significant predictors of IHD and hypertension, hyperlipidemia and a history of CI were significant predictors of CI. These results show that elevated serum Lp(a) concentrations is an independent risk factor for IHD, but not for the perforating artery occlusion type of CI in type 2 elderly diabetic patients.

Glufosinate ammonium induces convulsion through N-methyl-D-aspartate receptors in mice

Glufosinate ammonium, a broad-spectrum herbicide, causes convulsion in rodents and humans. Because of the structural similarities between glufosinate and glutamate, the convulsion induced by glufosinate ammonium may be ascribed to glutamate receptor activation. Three N-methyl-D-asparate (NMDA) receptor antagonists, dizocilpine, LY235959, and Compound 40, and an alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptor antagonist, NBQX, were coadministrated with glufosinate ammonium (80 mg/kg, intraperitoneally) in mice. Statistical analyses showed that the NMDA receptor antagonists markedly inhibited the convulsions, while the AMPA/kainate receptor antagonist had no effect on the convulsion. These results suggest that the convulsion caused by glufosinate ammonium is mediated through NMDA receptors.

Side-to-side arterial anastomosis model in the rat internal and external carotid arteries

Microvascular anastomosis has become a general and essential technique in the field of vascular reconstructive surgery. Side-to-side microvascular anastomosis is rarely performed by microsurgeons. Laboratory training models are essential for the development and refinement of microsurgical techniques. A new experimental model of a side-to-side "arterial" anastomosis in the rat internal and external carotid arteries is presented, in which 100 percent patency was accomplished immediately, and was maintained 7 days after anastomosis. This model can provide an experimental and training tool for side-to-side anastomosis of small arteries.

Severe congenital cytomegalovirus infection with fetal hydrops in a cytomegalovirus-seropositive healthy woman

We report the case of a woman whose two consecutive pregnancies resulted in intrauterine fetal death due to severe congenital cytomegalovirus infection. In both pregnancies, congenital cytomegalovirus infection was prenatally diagnosed on the basis of detection of cytomegalovirus DNA and specific IgM in cord blood. This case suggests that severe congenital cytomegalovirus infection can occur even in seropositive healthy women.

[A case of collecting duct carcinoma (Bellini duct carcinoma) producing carcinoembryonic antigen]

We report a case of collecting duct carcinoma (Bellini duct carcinoma) producing carcinoembryonic antigen (CEA). A 61-year-old man visited our hospital because of a left renal mass detected by ultrasonography in an other hospital. Computed tomography showed a low density tumor measuring about 3 cm in the left kidney. Angiography demonstrated a hypovascular tumor. The serum level of CEA was increased to 20 ng/ml. (normal < 7 ng/ml). Left radical nephrectomy was performed. Histological examination revealed collecting duct carcinoma with papillary growth (T1aN1M0). Cancer cells showed a positive immunohistochemical staining for CEA. Under a diagnosis of CEA-producing collecting duct carcinoma of the left kidney, the patient underwent systemic chemotherapy (M-VAC). The serum level of CEA decreased to the normal level after the nephrectomy, but six months postoperatively, metastatic bone tumor at the left pelvic bone was revealed on the plain film and at the same time, the CEA level was increased again.

Study on free radicals and pancreatic fibrosis--pancreatic fibrosis induced by repeated injections of superoxide dismutase inhibitor

The exact mechanisms of the development of pancreatic fibrosis are still unknown. To clarify the relationship between pancreatic fibrosis and free radicals, the effect of the administration of a superoxide dismutase (SOD) inhibitor, diethyldithiocarbamate (DDC), on pancreatic fibrosis in rats was studied. A single intraperitoneal injection of 500 mg/kg of DDC significantly reduced SOD activity and significantly increased lipid peroxidation products in the pancreas, showing no histologic changes of inflammation or necrosis. Repeated administration of 500 mg/kg DDC, twice a week, caused inter- and intralobular fibrosis with atrophy of acinar cells in the pancreas for at least 2 weeks without fibrosis of the liver and kidney. Administration of allopurinol showed preventive effects against DDC-induced pancreatic fibrosis. In conclusion, repeated administration of DDC, which caused pancreatic fibrosis, is a new experimental model of pancreatic fibrosis from the viewpoint of oxidative stress.

Intramedullary spinal teratoma with spina bifida

Spinal intramedullary teratoma is a rare tumor. We report a case of intramedullary teratoma of the conus medullaris with spina bifida. A 5-year-old boy was admitted to our hospital for removal of a lumbosacral tumor sited in an intramedullary location at the conus medullaris, which was totally resected with neuroendoscopic assistance. The pathological diagnosis was mature teratoma consisting of three germ cell layers. The pathogenesis of spinal intramedullary teratoma is discussed with special reference to spina bifida.

Determination of intracellular and extracellular beta-lactamase activities of Pseudomonas aeruginosa after exposure to beta-lactams in vitro and in vivo

Beta-lactamase production in Pseudomonas aeruginosa was determined in in-vitro models and in rat pouch infection models after exposure to ceftazidime, imipenem, and piperacillin. Exposure of 28 P. aeruginosa strains to 1/4 minimum inhibitory concentration (MIC) of ceftazidime, imipenem, and piperacillin for 24 h enhanced intracellular beta-lactamase activities in 14, 22, and 6 strains, respectively, of the 28 clinical strains tested, and enhanced extracellular beta-lactamase activities which were not detected without exposure to antibiotics, in 7, 23, and 1 of the 28 strains, respectively. Extracellular beta-lactamase activity from P. aeruginosa S-1278, producing an inducible beta-lactamase, scarcely increased after exposure to ceftazidime and piperacillin 24 h after incubation, while the activity increased after exposure to imipenem over the range of 1/8 to 8 MIC. In the rat granuloma pouch models infected with P. aeruginosa S-1278, ceftazidime and piperacillin, after single administration (20 mg/kg) and serial administration (20 mg/kg per day x 3 days), did not enhance extracellular beta-lactamase activities. However, the activities were enhanced with single and serial administrations of imipenem, and levels over 10 mU/ml were detected until the third day. The beta-lactamase activity, similar to the activity found in rat pouches after serial administration of imipenem, inactivated various cephalosporins. In conclusion, extracellular beta-lactamase activity was detected both in vitro and in vivo after exposure to a good inducer, and extracellular beta-lactamase remained at infection site at levels that could inactivate cephalosporins.

Changes in Helicobacter pylori-induced gastritis in the antrum and corpus during long-term acid-suppressive treatment in Japan

BACKGROUND

Several studies have shown that acid-suppressive therapy aggravates corpus gastritis in patients with Helicobacter pylori infection, promoting the development of atrophic gastritis.

AIM

To study the effects of long-term use of antisecretory agents on the H. pylori-positive gastric mucosa in Japan, a country with a high incidence of gastric cancer.

METHODS

A total of 141 H. pylori-positive patients who had peptic ulcers or reflux oesophagitis were treated for 3 years with either omeprazole (20 mg/day) alone (n=7) or with omeprazole for primary therapy (8 weeks), followed by famotidine (40 mg/day) for maintenance therapy (n=134). Endoscopy was performed before, during, and after treatment. Biopsy specimens were taken from the greater curvature of the antrum and corpus and were examined histologically.

RESULTS

The long-term use of famotidine after 8 weeks of treatment with omeprazole distinctly decreased H. pylori density and neutrophil infiltration in the antrum, but did not change H. pylori density in the corpus. The gastritis score increased in patients who had no, or only mild corpus gastritis before treatment (n=74), and significantly decreased in those who had moderate or severe gastritis before treatment (n=60). In four of the seven patients who received long-term treatment with omeprazole alone, neutrophil infiltration and H. pylori density decreased not only in the antrum but also in the corpus. There was no increase in intestinal metaplasia or mucosal atrophy as assessed endoscopically during follow-up.

CONCLUSION

Changes in corpus gastritis in response to acid-suppressive therapy depend on the severity of gastritis before treatment. Long-term use of acid-suppressive therapy apparently does not accelerate the development of atrophy or intestinal metaplasia in Japanese patients.

Amino acid substitutions in a variant of IMP-1 metallo-beta-lactamase

In the course of surveying for the carbapenem-hydrolyzing metallo-beta-lactamase gene bla(IMP) in pathogenic bacteria by the PCR method, we detected a gene encoding a variant metallo-beta-lactamase, designated IMP-3, which differed from IMP-1 by having low hydrolyzing activity for penicillins and carbapenems. PCR product direct sequencing of a 2.2-kb segment revealed that the gene bla(IMP-3) was located on a cassette inserted within a class I integron in the pMS390 plasmid. The 741-bp nucleotide sequence of bla(IMP-3) was identical to that of bla(IMP-1), except for seven base substitutions. Among these were two, at nucleotide positions 314 and 640, which caused amino acid alterations. Hybrid bla genes were constructed from bla(IMP-3) and bla(IMP-1) by recombinant DNA techniques, and beta-lactamases encoded by these genes were compared with those of the parents IMP-3 and IMP-1 under the same experimental conditions. The kinetic parameters indicated that the inefficient hydrolysis of benzylpenicillin, ampicillin, imipenem, and ceftazidime by IMP-3 was due to the substitution of glycine for serine at amino acid residue 196 in the mature enzyme. This alteration corresponded to the presence of guanine instead of an adenine at nucleotide position 640 of the bla(IMP-3) gene. This indicated that extension of the substrate profile in the metallo-beta-lactamase IMP-1 compared to IMP-3 is the result of a one-step single-base mutation, suggesting that the gene bla(IMP-3) is an ancestor of bla(IMP-1).

Changes in the serum levels of human chorionic gonadotropin and the pulsatility index of uterine arteries during conservative management of retained adherent placenta

OBJECTIVE

Our purpose was to assess the natural course of retained adherent placenta at term.

METHODS

Five cases of retained adherent placenta, clinically diagnosed as placenta accreta, were managed conservatively without methotrexate. To assess the biochemical and circulatory changes in the placentas, the serum levels of human chorionic gonadotropin (hCG) and the pulsatility index (PI) of the uterine arteries were examined.

RESULTS

Serum hCG levels decreased spontaneously; the half-life of serum hCG was calculated to be 5.2 +/- 0.26 days (mean +/- SEM). The PI of the uterine arteries remained at the level of pregnant women at term, but became elevated within a few days after the removal of the placentas. All the placentas were successfully removed transvaginally within 6 weeks postpartum.

CONCLUSIONS

The changes in serum hCG observed in this study indicated the spontaneous degeneration of the placenta. Such changes might be similar to those reported to occur during treatment with methotrexate. In contrast, the PI of the uterine arteries did not reflect degeneration of the placenta.

Purification and characterization of an extracellular alkaline serine protease from Aspergillus terreus (IJIRA 6.2)

An extracellular alkaline serine protease has been purified from Aspergillus terreus (IJIRA 6.2). The purification procedure involved chromatography on DEAE-Sephadex A25, phosphocellulose, hydroxyapatite, casein-Sepharose, gel filtration on Sephacryl-S-300 and by glycerol density gradient centrifugation. The enzyme was further purified to apparent homogeneity through a combination of electrophoresis in polyacrylamide gel containing 0.1% sodium dodecyl sulfate (SDS) with or without protease substrate (gelatin) and subsequent regeneration of its activity in situ by removal of SDS. The active enzyme was visualized in a zymogram or on the basis of protease activity exhibited on an X-ray film. The protein in the unstained segment of the gel was electroeluted. The eluted protein with protease activity exhibited a molecular mass of 37,000-daltons on electrophoresis in SDS-polyacrylamide gel. A sedimentation coefficient of 3.2S was obtained by glycerol density gradient contrifugation. Maximum activity of protease was observed at pH 8.5 and at 37 degrees C. Purified protease was active between pH 5.5 and 9.5 and was found to be stable up to 60 degrees C. With Na-caseinate, the K(m) of the purified protease was found to be 0.055 mM. Antipain, phenylmethane sulfonyl fluoride, and chymostatin served as non-competitive inhibitors. Substrate specificity was determined by using a synthetic chromogenic peptide containing N-P-Tosyl-Gly-Pro-Arg-p-nitroanilide. Results showed that the protease cleaved the peptide on the -COOH end of arginine residue.

High prevalence of herpes simplex virus type 2 in acute retinal necrosis syndrome associated with herpes simplex virus in Japan

PURPOSE

To determine the type of herpes simplex virus in acute retinal necrosis syndrome associated with herpes simplex virus.

METHODS

Herpes simplex virus type 1, herpes simplex virus type 2, varicella-zoster virus, Epstein-Barr virus, and cytomegalovirus were examined by polymerase chain reaction in intraocular specimens from 16 patients with acute retinal necrosis syndrome. Anti-herpes simplex virus type 1 and anti-herpes simplex virus type 2 type-specific antibodies in serum from the patients were detected by enzyme immunoassay.

RESULTS

Of 16 patients with acute retinal necrosis syndrome, seven were polymerase chain reaction positive for herpes simplex virus type 2 and nine were positive for varicella-zoster virus. Anti-herpes simplex virus type 2 antibody was positive and anti-herpes simplex virus type 1 antibody was negative in the sera of the seven patients with herpes simplex virus type 2 DNA-positive acute retinal necrosis syndrome. In contrast, anti-herpes simplex virus type 2 antibody was absent in all nine varicella-zoster virus DNA-positive acute retinal necrosis syndrome patients.

CONCLUSION

Herpes simplex virus type 2 has been demonstrated to be the major causative agent in acute retinal necrosis syndrome associated with herpes simplex virus by molecular biological and serological methods. Negative preexisting anti-herpes simplex virus type 1 antibody may play an important role in acute retinal necrosis syndrome associated with herpes simplex virus type 2.

An experimental model for side-to-side microvascular anastomosis

Side-to-side microvascular anastomosis may be required in certain clinical situations, although the technique is difficult and the incidence of usage remains low. A new experimental model using rat femoral vessels for side-to-side microvascular anastomosis is presented, in which 100 percent patency was accomplished immediately and was maintained for 7 days after anastomosis. This model can provide a training tool for acquisition of advanced microsurgical technique for side-to-side anastomosis of small vessels.

Role of permeability in the activities of beta-lactams against gram-negative bacteria which produce a group 3 beta-lactamase

The production of a group 3 beta-lactamase permitted Escherichia coli to raise the MICs of ceftazidime, cefpirome, and meropenem greatly but those of imipenem and piperacillin only slightly. The ratios of maximum rate of hydrolysis to K(m) of ceftazidime, cefpirome, and piperacillin were lower than those of meropenem and imipenem for the group 3 beta-lactamase. The permeability coefficients for piperacillin and meropenem were higher than those for ceftazidime and cefpirome. Imipenem had the highest permeability coefficient.

Successful treatment of advanced natural killer cell lymphoma with high-dose chemotherapy and syngeneic peripheral blood stem cell transplantation

CD56+ angiocentric lymphoma has currently been recognized as a distinct clinical entity which is the prototype of the putative NK cell lymphomas. A 16-year-old Japanese girl with advanced CD56+ angiocentric lymphoma received high-dose chemotherapy supported with syngeneic peripheral blood stem cell transplantation (PBSCT). Prior to syngeneic PBSCT, she received six cycles of conventional chemotherapy before transplantation, resulting in a partial response. PBSC were mobilized with granulocyte colony-stimulating factor (G-CSF) and collected from her identical twin. High-dose cyclophosphamide, MCNU, etoposide, and carboplatin were used for pretransplant conditioning. Syngeneic PBSCT was well tolerated. She achieved complete remission and is now surviving in continuous complete remission for more than 30 months after syngeneic PBSCT. Thus, marrow-ablative chemotherapy facilitated by autologous or allogeneic PBSCT should be considered as part of the primary therapy for poor prognosis NK cell lymphomas.

Stable expression in Chinese hamster ovary cells of mutated tau genes causing frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17)

Extensive neuronal loss and aggregation of tau as cytoplasmic inclusions in neurons and glial cells in selected cortical and subcortical regions is the most striking characteristic of frontotemporal dementia and parkinsonism linked to chromosome 17, which is caused by exonic or intronic mutations in the tau gene. Here, we examined the effects of four exonic mutations in four-repeat tau using stably transfected Chinese hamster ovary cells. The proportion of polymerized tubulin was the largest in the P301L transfectant. G272V and P301L transfectants showed greater instability of microtubules in the presence of Colcemid than wild-type tau, V337M, or R406W transfectants. Thus no distinct phenotypes were shared by the mutant tau transfectants with regard to microtubule assembly and stability. Unexpectedly, R406W showed low and negligible levels of phosphorylation at Thr 231 and Ser 396, respectively, in the transfectant. This presents a sharp contrast to the observation that tau aggregates in R406W-affected brains are heavily phosphorylated at these two sites. This result suggests that hyperphosphorylation at these sites cannot occur in the tau R406W bound to microtubules, and thus that the hyperphosphorylated species of tau may be generated only after disruption of microtubules.

Spatial- and task-dependent neuronal responses during real and virtual translocation in the monkey hippocampal formation

Neuropsychological data in humans demonstrated a pivotal role of the medial temporal lobe, including the hippocampal formation (HF) and the parahippocampal gyrus (PH), in allocentric (environment-centered) spatial learning and memory. In the present study, the functional significance of the monkey HF and PH neurons in allocentric spatial processing was analyzed during performance of the spatial tasks. In the tasks, the monkey either freely moved to one of four reward areas in the experimental field by driving a cab that the monkey rode (real translocation task) or freely moved a pointer to one of four reward areas on the monitor (virtual translocation task) by manipulating a joystick. Of 389 neurons recorded from the monkey HF and PH, 166 had place fields that displayed increased activity in a specific area in the experimental field and/or on the monitor (location-differential neurons). More HF and PH neurons responded in the real translocation task. These neurons had low mean spontaneous firing rates (0.96 spikes/sec), similar to those of rodent HF place cells. The remaining nonresponsive neurons had significantly higher mean firing rates (8. 39 spikes/sec), similar to interneurons or theta cells in the rodent HF. Furthermore, most location-differential neurons showed different responses in different tasks. These results suggest that the HF and PH are crucial in allocentric information processing and, moreover, that the HF can encode different reference frames that are context or task-dependent. This may be the neural basis of episodic memory.

A plasmid-mediated beta-lactamase with carbapenem-hydrolyzing activity from Serratia marcescens

Serratia marcescens W-313/pSW313 was isolated from a clinical specimen that showed resistance to various beta-lactams. beta-Lactamase from this strain hydrolyzed oxyiminocephalosporins and carbapenems, but did not hydrolyze 2-carboxypenam and aztreonam. The kinetic parameters of this enzyme were similar to those of the carbapenem-hydrolyzing beta-lactamases mediated by R-plasmid from Pseudomonas aeruginosa and S. marcescens, whose properties were previously reported.