Aspergillus culture filtrates and sputum sols from patients with pulmonary aspergillosis cause damage to human respiratory ciliated epithelium in vitro

Aspergillus species frequently colonize lower respiratory tracts and lungs with localized underlying conditions (healed tuberculous cavity, cystic fibrosis, bronchiectasis, etc.) even in subjects without systemic predisposing factors. We investigated the in vitro effects of culture filtrates of Aspergillus species and sputum sols from patients with pulmonary aspergillosis on ciliary beat frequency (CBF) and epithelial integrity of human respiratory ciliated epithelium. Culture filtrates of 25 clinically isolated fungi (16 Aspergillus fumigatus, three Aspergillus niger, one Aspergillus flavus, three Candida albicans, and two Cryptococcus neoformans) were obtained by culturing the fungi in Medium-199 at 37 degrees C for 7 days, and five sputum sols were obtained from patients with pulmonary aspergillosis infected by A. fumigatus. During 6 h experiments using a photometric technique, 14 out of 16 A. fumigatus culture filtrates caused progressive and significant reduction in CBF associated with marked epithelial disruption, whilst the culture filtrates of A. niger and A. flavus caused minor epithelial damage without slowing of CBF, and Medium-199 alone (Control) showed neither epithelial damage nor slowing of CBF. All of the sputum sols also caused significant slowing of CBF as well as epithelial disruption. Culture filtrates of C. albicans and Cr. neoformans had no effects on human respiratory epithelium. We conclude that Aspergillus species, especially A. fumigatus release a factor (or factors) which causes damage to respiratory epithelium and slows CBF, and that these factors may contribute to the colonization of the lower respiratory tracts by the Aspergillus species and may possibly contribute to the further proliferation and spread of the lesions in pulmonary aspergillosis.

[Study on sepsis in the elderly at Nagoyashi-Koseiin Geriatric Hospital]

A study based on clinical analysis was conducted regarding the 125 episodes in the elderly 112 patients of sepsis who were 70 (average 83.8 +/- 7.5) years old at Nagoyashi-Koseiin Geriatric Hospital from 1985 through 1994. 1) The backgrounds of the elderly patients with sepsis were as follows: bedridden (72.8%), urinary catheter in place (61.2%), central venous catheter in place (48.8%), and prior antibiotic use (40.8%). All patients had an underlying disease. 2) Organisms isolated were Escherichia coli (21.2%), Staphylococcus aureus (18.4%); Coagulase-negative staphylococci (CNS) (17.4%) and Candida albicans (6.1%). Chronologically, the quantity of gram-positive cocci increased while that of gram-negative bacilli decreased. As the age of the patients increased, the frequency of infections by Methicillin-resistant Staphylococcus aureus (MRSA), E. coli, and/or multiple bacteria increased, while that of infections by CNS and gram-negative bacilli excluding E. coli decreased. 3) The primary infected sites were the urinary tract system (24.8%), central venous catheter (21.6%) and unknown (31.2%). 4) The primary clinical observations were fever exceeding 38.0 degrees C (88.0%), tachycardia (60.8%), shivering (44.0%) and cyanosis (32.8%). 5) Complications were multiple organ failure (33.6%), septic shock (26.4%) and disseminated intravascular coagulation (22.4%). 6) The prognosis indicated that 65.6% were survivors, and 34.4% were nonsurvivors. At the onset of sepsis, weight, blood pressure, serum albumin, and total cholesterol in the nonsurvivors were significantly lower than those in the survivors, whereas heart rate, GOT, LDH, and BUN in the nonsurvivors were significantly higher than those in the survivors.

[Clinical significance of proliferating cell nuclear antigen (PCNA) and argyrophilic nucleolar organizer region (AgNOR) in testicular tumors]

BACKGROUND

Proliferative potential of testicular tumor was assessed by immunohistochemistry using anti-proliferating cell nuclear antigen (PCNA) monoclonal antibody and silver staining of argyrophilic nucleolar organizer region (AgNOR), and the results were compared with clinical course.

METHODS

Fourty-five patients with testicular tumor and 10 normal testicles were investigated. All specimens were fixed with 10% buffered formaliun within 24 hours. The interval between patient's recognition of testicular swelling for the first time and the date for operation was designated as M (months), and the specimen weight was designated as g (gram). Growth rate of the primary tumor was estimated roughly by g/M.

RESULTS

PCNA positive rates in seminomas, non-seminomas and normal testes were 70.5 +/- 19.1% (mean +/- S.D.), 80.4 +/- 10.5% and 17.7 +/- 7.8%, respectively. PCNA positive rate in stage I seminoma (64.4 +/- 19.9%) was significantly lower than stage II and III seminoma (83.6 +/- 7.3%) (p < 0.05), but not significant between stage I non-seminoma and stage II, III non-seminoma. The mean numbers of AgNOR per nucleus in seminomas, non-seminomas and normal testes were 8.09 +/- 1.35 (mean +/- S.D.), 6.89 +/- 1.43, 4.18 +/- 1.60, respectively and significantly higher in testicular tumors than normal testes. There were, however, no significant difference between their clinical stages. Logarithmic significant correlation was observed between PCNA positive rate and the growth rate in primary lesion, but no correlation was found between mean number of AgNOR per nuclei and the growth rate. Of the 10 patients with stage I non-seminomas received surveillance policy, four relapsed. Of the 10 patients, 4 of the 6 patients with higher than 75% PCNA positive rate relapsed, whereas, none of the 4 patients with lower than 75% PCNA positive rate relapsed. There were no significant correlation between PCNA positive rate and number of AgNOR.

CONCLUSION

PCNA is more accurate indicator of growth potential in testicular tumor than AgNOR and may predict recurrence in stage I non-seminomatous testicular tumor patients followed by surveillance policy.

[Exocrinopathy resembling Sjögren's syndrome induced by a murine retrovirus]

Recently, retrovirus is suggested to participate in the pathogenesis of Sjögren's syndrome (SjS). During the course of our study on mice infected with LP-BM5 murine leukemia virus, we found SjS-like systemic exocrinopathy in those mice. This virus is known to induce murine acquired immunodeficiency syndrome (MAIDS) in sensitive strains of mice. Most cells infiltrating into the glands were composed of CD3+ T cells (CD4-dominant), Mac-1+ cells and also B220+ cells. The virus genome was detected in the submandibular glands by immunohistochemistry or by PCR and the retroviral particles were also detected by electron microscopy. This mice might become an animal model for SjS and provide us with valuable informations for analysing the mechanism of how a retrovirus could induce SjS.

[Primary pulmonary amyloidosis with multiple nodules]

A 42-year-old man complained of a productive cough and exertional dyspnea. Roentgenogram and computed tomography of the chest showed several nodular shadows, and an open lung biopsy was done. Congo-red staining and electron microscopy showed the pulmonary nodules to be amyloid with infiltration by plasma cells and foreign body giant cells. The amyloid was identified as AL-lambda and kappa type by immunohistochemical examination, and plasma cells and foreign body giant cells contained light chains. In situ hybridization studies showed intens signals of lambda mRNA and kappa mRNA in the plasma cells, but no signal in the foreign body giant cells. The foreign body giant cells appeared to have phogocytosed the light chains. Electron microscopic examination showed an "amyloid star" in the foreign body giant cells. Morphologically, this observation showed that the amyloid was produced by the foreign body giant cells.

Pathophysiology and postnatal pathogenesis of hypoplastic kidney (hpk/hpk) in the male hypogonadic mutant rat (hgn/hgn)

The male hypogonadic rate (hgn/hgn) is accompanied with bilateral hypoplastic kidney (HPK; hpk/hpk)[34]. In this study, we examined the kidney weight (KW), glomerular number (GN), renal pathohistology at adult (80 days of age), and pathogenesis during the early postnatal stage in the hpk/hpk, +/hpk, and +/+ rat. The GN of adult hpk/hpk was significantly less that that of the +/hpk and +/+. Histologically, there were the decreased number of nephrons and the associated secondary changes in the hpk/hpk kidney. The plasma concentrations of urea nitrogen and creatinine were significantly higher in the hpk/hpk than in the +/hpk and +/+. During early postnatal stage, the KW of the hpk/hpk was significantly smaller than those of the +/hpk and +/+, and the GN was fewer in order of the hpk/hpk, +/hpk and +/+, showing the significant differences between given genotypes. The layer of nephrogenic nephron beneath the renal capsula of the neonatal kidney appeared to be thinner in the hpk/hpk than in the normal (+/hpk and +/+). In the hpk/hpk kidney on 3 days of age, the layer of the nephrogenic nephron was absent in some portions beneath the renal capsula. In the hpk/hpk kidney on 7 days of age, further, the layer of immature type of nephron was still observed under the capsula. These studies suggest that the hypoplastic kidney, which may result from reduced nephrogenesis, could not compensate the real weight, GN and renal function during the postnatal nephrogenic stage.

[A case of chronic scrotal hematocele]

A 60-year-old man visited our hospital because of a painless swelling of the left scrotal content which enlarged gradually for these five years. He had no history of trauma at the perineum. Tumor markers such as HCG, AFP and CEA were within normal limits. Left high orchiectomy was carried out after the admission under the diagnosis of suspicious testicular cancer. The resected mass, 16.5 x 12.5 x 9.5 cm in diameter and 900 g in weight, was encapsulated within the tunica vaginalis by a fibrous membrane and contained about 300 ml of reddish black liquid. The normally-appearing left testis was located separately from the mass. Microscopic examination revealed depositions of cholesterine crista in the wall, which are characteristic for a chronic hematocele.

Carboplatin-based combination chemotherapy for testicular cancer: relationship among administration dose of carboplatin, renal function and myelosuppression

Carboplatin (CBDCA), a derivative of cis-diamminedichloroplatinum, has low renal and neural toxicity. The dose-limiting factor of this agent is myelosuppression. We experienced various degrees of myelosuppression, when the dose of CBDCA was determined by the body surface area (BSA) in CBDCA-based combination chemotherapy for testicular cancer. Calvert demonstrated that the dose of CBDCA administered should be adjusted by renal function, because CBDCA was excreted through the glomerulus. We report the relationship among 3 factors; the administration dose of CBDCA, renal function and the degree of myelosuppression. We treated 6 patients with testicular cancer. A total of 22 courses of CBDCA-based combination chemotherapy was performed. The area under the curve (AUC) was calculated by the following formula, which was demonstrated in Calvert's study. CBDCA dose = AUC x (GFR + 25), GFR; glomerular filtration rate. The degree of myelosuppression was examined. All chemotherapy courses were divided into 2 and 3 groups according to BSA and AUC, respectively. WBC and Plt reduction rates and nadir counts were significantly correlated with AUC, and showed no significant relationship to the dose determined by BSA. This study revealed that the degree of myelosuppression was closely related with AUC, which reflects the renal function.

Yersinia pseudotuberculosis in China

Thirty strains of Yersinia pseudotuberculosis were isolated from rabbits (17 strains), wild rats (9 strains) and house rats (4 strains) in China between 1990 and 1993. The biochemical properties of these isolates were identical with those of Y. pseudotuberculosis and no special characteristics were found in these strains. Serologically, serogroups 4b and 5b were identical to isolates found in Japan, and a new serogroup 1c and unclassified strains have also been detected. The existence of virulence-associated properties were different among strains. The pYV plasmid was detected from 6 strains of 30 isolates. This report documents the presence of Y. pseudotuberculosis in China, providing important epidemiological information.

Normal human cells at confluence get heat resistance by efficient accumulation of hsp72 in nucleus

We investigated the heat-sensitivity of normal human cells and cells derived from human cancers (cancer cells) heated at 43 degrees C under different culture conditions. Primary human cells which keep in contact with each other show heat resistance, but cancer cells do not. This does not correlate with the total cellular amount of heat shock protein 72, but rather with accumulation of the protein in the nucleus after heating.

Hemostatic abnormalities in patients with pulmonary embolism compared with that in deep vein thrombosis

We investigated hemostatic abnormalities in 37 patients with deep vein thrombosis (DVT) and pulmonary embolism (PE) (PE patients) and in 40 patients with DVT without PE (DVT patients). Plasma fibrinogen, thrombin-antithrombin complex (TAT), plasmin-plasmin inhibitor complex, fibrin-D-dimer, activated protein C (APC)-protein C inhibitor (PCI) complex, von Willebrand factor (vWf), tissue plasminogen activator (t-PA), PA inhibitor-I (PAI-1), and thrombomodulin levels in both PE and DVT patients were significantly increased compared with normal volunteers. Plasma APC-PCI complex, PAI-1, and vWf levels in PE patients were significantly higher than those in DVT patients without PE. These findings indicate that PE patients are more hypercoagulable and hypofibrinolytic than DVT patients. Plasma TAT, APC-PCI complex, PAI-1, and vWf levels were the most sensitive indicators for PE. In these patients, increases in TAT and APC-PCI complex suggest DVT and increased PAI-1 and vWf suggest the risk of onset of PE.

Three distinct phases of fodrin proteolysis induced in postischemic hippocampus. Involvement of calpain and unidentified protease

BACKGROUND AND PURPOSE

Fodrin, a neuronal cytoskeleton protein, is proteolyzed by calpain after ischemic insult. We examined proteolysis of fodrin induced by global forebrain ischemia in gerbil hippocampus in spatial terms by using the antibody specific to the calpain-proteolyzed form of fodrin.

METHODS

In gerbils, a 10-minute forebrain ischemia was produced by occlusion of both carotid arteries. After recirculation, the hippocampus was processed for immunohistochemical and immunoblot study with the antibody against the calpain-proteolyzed form of fodrin. Additionally, short-term ischemia was studied to find the threshold of fodrin proteolysis.

RESULTS

Three phases of fodrin proteolysis distinct in chronology and distribution arose: (1) an early predegeneration phase in the molecular layer and stratum oriens of the CA1 and CA3 sectors within the first 15 minutes, which lasted up to 4 hours; (2) a late predegeneration phase in the whole CA1 sector, except for the pyramidal cells, between 12 hours and 2 days; and (3) a postdegeneration phase in the cytoplasm of the CA1 neurons, which arose in 3 to 7 days. A 4-minute (not a 3-minute) forebrain ischemia induced the late predegeneration phase of fodrin proteolysis and delayed neuronal death in CA1. Immunoblotting showed that the primary product of calpain action was further proteolyzed by an unidentified protease.

CONCLUSIONS

Calpain induced proteolysis of fodrin in ischemic hippocampus, and the late predegeneration phase of the proteolysis was closely associated with the delayed neuronal death in the CA1 sector. Calpain and another protease may play a role in the development of neuronal death after transient forebrain ischemia.

Augmentation of transport for cisplatin-glutathione adduct in cisplatin-resistant cancer cells

We studied the outward transport of cisplatin (CDDP)-glutathione (GSH) adduct (DDP-GSH) in CDDP-resistant cancer cells. Incubating the cells in the presence of CDDP resulted in the formation of an adduct with GSH and subsequent transport outside the cells. We used human colonic cancer cells sensitive (HCT8) and resistant (HCT8DDP) to CDDP and human ovarian cancer cells sensitive (A2780) and resistant (A2780DDP) to CDDP as materials. The concentration of intracellular GSH was higher in the resistant cells (118.7 +/- 5.9 nmol/10(6) HCT8DDP versus 19.0 +/- 1.0 nmol/10(6) HCT8 and 24.1 +/- 1.2 nmol/10(6) A2780DDP versus 9.4 +/- 0.5 nmol/10(6) A2780, respectively). The activity of the GSH-synthesizing enzyme, gamma-glutamylcysteine synthetase (gamma-GCS) was higher in the CDDP-resistant cells (7.1 +/- 0.2 milliunits/10(6) HCT8DDP versus 2.2 +/- 0.1 milliunits/10(6) HCT8 and 2.9 +/- 0.1 milliunits/10(6) A2780DDP versus 1.4 +/- 0.1 milliunits/10(6) A2780, respectively). Furthermore, immunological levels of gamma-GCS and the expression of gamma-GCS mRNA were higher in these CDDP-resistant cells than those in the control cells, in accordance with the change in the concentration of GSH. DDP-GSH transport increased in the CDDP-resistant colonic cancer cells by 219% (324 +/- 12 fmol/10(6) HCT8DDP cells/min versus 148 +/- 11 fmol/10(6) HCT8 cells/min) and the CDDP-resistant ovarian cancer cells by 126% (127 +/- 7 fmol/10(6) A2780DDP cells/min versus 101 +/- 8 fmol/10(6) A2780 cells/min). DDP-GSH transport was also estimated using inside-out vesicles from these cells. The active transport of DDP-GSH was 243% of HCT8 in HCT8DDP and 121% of A2780 in A2780DDP. These data suggest that the acquisition of CDDP resistance in cancer cells is due partly to the increase in the transport of DDP-GSH outside the cells as well as the increase in the concentration of GSH. Immunological estimation of the membrane proteins against human erythrocyte glutathione S-conjugate-stimulated Mg(2+)-ATPase sera resulted in no apparent cross-reactivity, suggesting that there are several transport systems for DDP-GSH.

Xenotransplantation and high tumorigenicity of feline tumors in SCID mice

Nine feline tumors resected at surgery were subcutaneously xenotransplanted into SCID mice. The primary take rate of the benign and malignant tumors was 50% (1/2) and 100% (7/7) respectively. Six of the eight primary tumor xenografts transplanted and grown in the first recipient were successfully transplanted serially. One feline mammary adenocarcinoma xenograft metastasized to the lung of a SCID mouse. The primary take rate of feline tumors to SCID mice was high and the established xenografts appear to be valuable tools for investigating growth and metastasis mechanisms, and various therapies for feline neoplasms.

Lower leg fracture with Parkes-Weber syndrome complicated by disseminated intravascular coagulation

Reports of Parkes-Weber syndrome complicated by disseminated intravascular coagulation (DIC) are rare in the orthopaedic literature. This is a case report of a 23-year-old man who had this syndrome and who sustained a lower-leg fracture complicated by the DIC. Open reduction was not attempted because the DIC worsened after manual reduction. Amputation was rejected by the patient. Three months of continuous infusion of heparin and replacement therapy with fresh frozen plasma was done. Cast immobilization without further reductions was continued. The DIC improved and union of the fractures was observed at 2 years and 3 months after injury.

Interleukin 1 alpha-induced expression of manganous superoxide dismutase reduces myocardial reperfusion injury in the rat

We investigated the effects of pretreatment with interleukin (IL)-1 alpha on the expression of manganous (Mn) superoxide dismutase (SOD) mRNA and reperfusion-induced arrhythmias and the size of myocardial infarct in rats. Male Wistar rats received 10 mg intraperitoneal injections of human recombinant IL-1 alpha. Their hearts were thereafter isolated at 6, 12, 24, 36 h. A Northern analysis showed that Mn-SOD mRNA was mainly expressed in the heart and slightly in kidney, but not in any other organs. The expression of Mn-SOD mRNA peaked at 6 h after the injection of IL-1 alpha. The Mn-SOD protein content was most increased 12 h after injection. In the isolated heart model, the rats were pretreated with IL-1 alpha 24 h earlier and their hearts were perfused by the Langendorff method. After 20 min of ischemia which was induced by a ligation of a coronary artery, reperfusion-induced arrhythmias were observed. There were no significant differences in the incidence of ventricular arrhythmias between the IL-1 alpha pretreated and the untreated hearts. IL-1 alpha pretreatment significantly reduced the mean duration of the ventricular arrhythmias and also delayed the onset of arrhythmias. The effect of IL-1 alpha pretreatment was also investigated in a 30-min model of ischemia followed by a 3-min reperfusion in anesthetized rats. The infarct size expressed as a percentage of the area at risk was significantly reduced in the IL-1 alpha pretreated hearts compared with the untreated hearts. The left ventricular systolic pressure increased significantly in rat hearts pretreated with IL-1 alpha. Our results therefore showed that the pretreatment with IL-1 alpha induced the overexpression of Mn-SOD mRNA in the rat hearts and also suggested that pretreatment with IL-1 alpha 24 h before ischemia reduced the risk of ischemia-reperfusion injury.

A novel pyridobenzazepinone derivative with long lasting thromboxane synthase inhibition

A novel pyridobenzazepinone derivative (Z)-11-(5-carboxypentylidene)-6-methyl-5, 11-dihydropyrido +ad4,3-C] [1] benzazepin-5 (6H)-one (CAS 127654-03-9, KF 13218), inhibited human and bovine platelet thromboxane synthase with IC50 values of 27 +/- 5.8 nmol/l (mean +/- S.E.M.) and 36 +/- 6.9 nmol/l, respectively. The compound did not inhibit cyclooxygenase or 5-lipoxygenase up to a dose of 100 mumol/l and did not antagonize thromboxane A2/prostaglandin H2 receptors. KF13218 inhibited arachidonic acid-induced thromboxane B2 production by human intact platelets with an IC50 value of 5.3 +/- 1.3 nmol/l. The IC50 value of KF13218 for the intact platelets was about 5 times lower than that for the microsomal enzyme. The inhibition of thromboxane synthase in platelets by KF13218 was sustained after removal of the extracellular compound. After oral dosing in rat from 0.03 mg/kg to 3 mg/kg, KF13218 dose-dependently inhibited the thromboxane B2 production in serum, and the inhibition was retained for 72 h. KF13218, at a dose of 0.1 mg/kg p.o. prevented mortality induced by sodium arachidonate in rabbit. It is concluded that KF13218 is a potent, selective and long lasting thromboxane synthase inhibitor.

Mouse models of Tay-Sachs and Sandhoff diseases differ in neurologic phenotype and ganglioside metabolism

Tay-Sachs and Sandhoff diseases are clinically similar neurodegenerative disorders. These two sphingolipidoses are characterized by a heritable absence of beta-hexosaminidase A resulting in defective GM2 ganglioside degradation. Through disruption of the Hexa and Hexb genes in embryonic stem cells, we have established mouse models corresponding to each disease. Unlike the two human disorders, the two mouse models show very different neurologic phenotypes. Although exhibiting biochemical and pathologic features of the disease, the Tay-Sachs model showed no neurological abnormalities. In contrast, the Sandhoff model was severely affected. The phenotypic difference between the two mouse models is the result of differences in the ganglioside degradation pathway between mice and humans.

Stimulation of sky receptor tyrosine kinase by the product of growth arrest-specific gene 6

Sky (also called Rse, Brt, and Tyro3) is a member of a subfamily of related receptor tyrosine kinases, including Axl/Ufo/Ark and c-Eyk/Mer. We obtained evidence that Gas6 (the product of growth arrest-specific gene 6) is a ligand of the Sky receptor tyrosine kinase. Gas6, but not protein S (an anticoagulant protein structurally similar to Gas6), specifically bound to the soluble form of Sky (Sky-Fc), composed of the extracellular domain of Sky fused to the Fc domain of human immunoglobulin G1. The native and recombinant Gas6, but not protein S, stimulated tyrosine phosphorylation of Sky ectopically expressed in Chinese hamster ovary cells. Stimulation of Sky in response to Gas6 was inhibited by Sky-Fc. The half-maximal concentration of Gas6 that stimulated Sky was about 1 nM. Thus, Gas6 as a ligand for Sky specifically binds to and stimulates Sky receptor tyrosine kinase.

Alterations of superoxide dismutase iso-enzyme activity, content, and mRNA expression with aging in rat skeletal muscle

The alterations of superoxide dismutase iso-enzyme (Cu,Zn-SOD and Mn-SOD) activities, contents, and mRNA expressions with aging were studied in rat soleus muscle (SO) and extensor digitorum longus muscle (EDL). The activity and content of Cu,Zn-SOD in both muscles were significantly higher in old rats (24 months old) than in young rats (4 months old), whereas those of Mn-SOD showed no difference between young and old rats. After normalization to citrate synthase (CS) activity, however Mn-SOD/CS ratio in SO also showed the age-related increase. Moreover, the activities of other major antioxidant enzymes, glutathione peroxidase (GPX) and catalase (CAT), indicated age-related increases only in SO. As for the expressions of mRNAs for SOD iso-enzymes, that of Cu,Zn-SOD in either muscle showed no significant change with aging, unlike its activity and content, although that of Mn-SOD was decreased with aging only in EDL. Thus, aging appeared to raise the level of antioxidant enzyme system in rat skeletal muscle. However, the resistance of Cu,Zn-SOD and Mn-SOD to oxidative stress accompanied by aging was different, the former being obviously greater than the latter. Such changes also differed in muscle fiber type suggesting that fast-twitch fibers are more susceptible to age-related oxidative stress than slow-twitch fibers.

Inactivation of glutathione peroxidase by nitric oxide. Implication for cytotoxicity

S-nitro-N-acetyl-DL-penicillamine (SNAP), a nitric oxide (NO) donor, inactivated bovine glutathione peroxidase (GPx) in a dose- and time-dependent manner. The IC50 of SNAP for GPx was 2 microM at 1 h of incubation and was 20% of the IC50 for another thiol enzyme, glyceraldehyde-3-phosphate dehydrogenase, in which a specific cysteine residue is known to be nitrosylated. Incubation of the inactivated GPx with 5 mM dithiothreitol within 1 h restored about 50% of activity of the start of the SNAP incubation. A longer exposure to NO donors, however, irreversibly inactivated the enzyme. The similarity of the inactivation with SNAP and reactivation with dithiothreitol of GPx to that of glyceraldehyde-3-phosphate dehydrogenase, suggested that NO released from SNAP modified a cysteine-like essential residue on GPx. When U937 cells were incubated with 100 microM SNAP for 1 h, a significant decrease in GPx activity was observed although the change was less dramatic than that with the purified enzyme, and intracellular peroxide levels increased as judged by flow cytometric analysis using a peroxide-sensitive dye. Other major antioxidative enzymes, copper/zinc superoxide dismutase, manganese superoxide dismutase, and catalase, were not affected by SNAP, which suggested that the increased accumulation of peroxides in SNAP-treated cells was due to inhibition of GPx activity by NO. Moreover, stimulation with lipopolysaccharide significantly decreased intracellular GPx activity in RAW 264.7 cells, and this effect was blocked by NO synthase inhibitor N omega-methyl-L-arginine. This indicated that GPx was also inactivated by endogenous NO. This mechanism may at least in part explain the cytotoxic effects of NO on cells and NO-induced apoptotic cell death.

Effect of age on the induction of endometrial lesions by a single intra-uterine administration of N-ethyl-N'-nitro-N-nitrosoguanidine in F344 rats

A total of 54 10-week-old or 49 10-month-old female F344 rats were given a single intrauterine administration of 20 mg/kg N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) dissolved in polyethylene glycol (PEG) via the vagina using a non-laparotomy approach. Control animals (32 10-week-old or 29 10-month-old rats) were given PEG alone in the same manner. The animals were killed at 15 and 18 months of age, respectively. One animal in the young treated group presented an endometrial adenocarcinoma (incidence: 2.1%), although the incidence and degree of endometrial hyperplasias were significantly increased in both groups of treated animals, as compared to corresponding controls. Histologically, many of these lesions were polypous glandular hyperplasias (adenomatous polyps) with stromal proliferation. The incidence and grade of proliferative lesions in the young treated group were slightly higher than those in the old treated group. ENNG administration did not appear to affect the hormonal situation in treated animals. These results indicate that young animals may be more sensitive to ENNG than aged ones for induction of endometrial lesions, although ENNG-treatment alone is not sufficient for early and high induction of carcinomas even in young rats of this strain.

Prevention of local recurrence by extended lymphadenectomy for rectal cancer

This study was undertaken to determine if the degree of lymphadenectomy correlates with the prevention of local recurrence. The authors retrospectively reviewed the clinical data of 269 patients who underwent curative surgery for rectal cancer. The study was divided into three periods based on the method of lymphadenectomy as follows: period I (1963-1979) when extended lymphadenectomy was not performed; period II (1980-1985) when this was partially done with no attempt to dissect the obturator and proximal middle rectal lymph nodes; and period III (1986-1990) when this was completely performed for patients with appropriate indications. The local recurrence rates were 21%, 10%, and 8% for Periods I, II, and III, respectively (P < 0.05). The incidence of local recurrence tended to be greater in period I versus periods II and III according to type of operation, location, and stage of the primary tumors. The local recurrence rates arising from lateral node metastases were 11%, 4%, and 2% for periods I, II, and III, respectively (P < 0.05), while the incidence related to an insufficient surgical margin was approximately 5% throughout the three periods. We thus conclude that the degree of lymphadenectomy is a major determinant of local recurrence following a curative operation for rectal cancer.