[Mini review: a factor enhanced the antibacterial effect of beta-lactams on methicillin-resistant Staphylococcus aureus]

We found a factor (Factor T) in aged mixtures of tungstate and phosphate which greatly enhances the antibacterial effects of beta-lactams on methicillin-resistant Staphylococcus aureus (MRSA), while Factor T alone did not strongly inhibit bacterial growth. The effect on methicillin-susceptible S.aureus was weak. There was no synergism of Factor T with other classes of antibiotics, nor with other groups of bacteria. Factor T is probably a complex of phosphate and tungstate, and reduced the expression of penicillin-binding protein-2', thus sensitizing the MRSA strains to beta-lactams.

Epstein-Barr virus-associated undifferentiated carcinoma with lymphoid stroma of the salivary gland in Japanese patients. Comparison with benign lymphoepithelial lesion

BACKGROUND

Undifferentiated carcinoma with lymphoid stroma (UCLS) arising in the salivary gland is a rare tumor, except for its geographic concentration among Eskimo and southern Chinese populations. Five cases of salivary gland UCLS in Japanese patients are presented here and compared with benign lymphoepithelial lesions (BLELs) with regard to their association with Epstein-Barr virus (EBV), p53 expression, and cell proliferative activity.

METHODS

Formalin fixed, paraffin embedded sections of 5 cases of UCLS selected from 1676 patients with primary tumors of the major salivary gland and 7 cases of BLEL were examined using in situ hybridization for EBV-encoded RNAs (EBERs), along with immunostaining for p53 and Ki-67 (MIB-1).

RESULTS

The incidence of UCLS was 0.3% among patients with major salivary gland tumors. EBER hybridization signals were strongly expressed in most of the neoplastic cells in all five cases of UCLS, whereas there was no signal in BLEL and surrounding nontumorous salivary gland tissues. All cases of UCLS showed strongly positive immunostaining for p53 in the tumor cell nuclei. By contrast, only one case of BLEL was positively stained for p53 in dysplastic epimyoepithelial cells, which showed focal immunostaining. Cell proliferative activity assessed using the Ki-67 labeling index was significantly higher in tumor cells of UCLS than in epimyoepithelial cells of BLEL.

CONCLUSIONS

UCLS of the salivary gland is an extremely rare tumor in Japanese patients characterized by consistent association with EBV. Distinction between BLEL and UCLS is possible by examining for evidence of EBV infection, expression of p53, and cell proliferative activity.

Perforated patch-clamp recording in cardiac myocytes using cation-selective ionophore gramicidin

Whole cell currents were recorded in single myocytes dissociated from guinea pig ventricles by the patch-clamp technique. The addition of 0.1 mg/ml gramicidin D, a cation-selective ionophore, into the pipette solution induced a gradual spontaneous perforation of the patch membrane under a conventional cell-attached configuration. The access resistance, measured at approximately 12 min after formation of a gigaohm seal, was 9.2 +/- 1.5 M omega (n = 12). The perforated patch membrane exhibited ionic selectivity for various monovalent cations, with a relative order of Cs+ (1.11) > K+ (1.0) > Na+ (0.65) >> tris(hydroxymethyl)aminomethane+ (approximately 0) but was not permeable for Cl-. Under the gramicidin-perforated patch recording configuration, the cells showed the typical electrophysiological properties for ventricular cells reported previously. The intracellular Cl- concentration, estimated from the reversal potential of the catecholamine-induced Cl- current, was 36.3 +/- 2.9 mM (n = 17). We thus conclude that the gramicidin-perforated patch recording mode provides a useful tool for recording the ionic currents while maintaining the intracellular Cl- concentration.

In vivo modulation of proliferating cell nuclear antigen in growth plate chondrocytes from normal, hypophysectomized, growth hormone-treated hypophysectomized rats: a comparative immunohistochemical study with image analysis

Growth hormone (GH) regulates the proliferation and maturation of chondrocytes in the epiphyseal growth plate, in which a temporal dimension is superimposed on the septal organization of the tissue. In this study we investigated the in vivo effects of hypophysectomy (Hypox) and injection of GH into Hypox animals (Hypox + GH) on the proliferative activity of the growth plate chondrocytes. We assessed the immunohistochemical expression of proliferating cell nuclear antigen (PCNA) in paraffin-embedded tissues, using monoclonal antibody PC 10 against PCNA combined with immunogold-silver staining. We subjected the immunostained sections to computer-based image analysis by ACAS 570 interactive laser cytometry employing a conventional microscopic light source. Hypox was carried out on 20 rats at 8 weeks of age, half of which received a hypodermic injection of human GH at a dose of 1 IU/kg twice a day for 1 week after the operation. Another group of five rats of the same age were used as normal controls. In normal rats, a distinct PCNA immunoreaction was observed in the proliferative zone, whereas a remarkable diminution of the number of immunoreactive cells in this zone was apparent in Hypox animals. On the other hand, marked hyperplasia of PCNA-positive cells was seen in the proliferative zone of the Hypox + GH rat growth plate. The immunoreactive cells of this zone in Hypox + GH animals exhibited increased nuclear size and staining intensity of PCNA compared with those in normal and Hypox rats. These findings were further confirmed by computer-based image analysis of the specimens in terms of cell integrated value, area, perimeter, and shape factor. These different patterns of PCNA expression may imply that GH specifically promotes the proliferation phase of the chondrocytes in the proliferative zone. The data also suggest that GH influences not only cell replication activity but also cell kinetics of chondrocytes in the growth plate during their lifespan.

A new, secure drainage method from the cystic duct after choledocholithotomy using the cystic tube and the cystic clip: an experimental study

The effectiveness of the cystic tube (C-tube) and the cystic clip (C-clip) for primary closure of the common bile duct after choledocholithotomy was examined in 10 dogs, followed by an observation period of either 3 months (n = 6) or 1 year (n = 4). No early complications were observed in any of the animals either during or after surgery. The laboratory data were within the normal range during the observation period. No bile leakage or slippage of the C-clip was evident on fistulography from the C-tube in animals examined 5 days after surgery. The tube could be pulled out easily from the cystic duct without any bile leakage or slippage of the clip. A second operation to confirm late complications showed no adhesions around the common bile duct, no bile duct stenosis similar to the Mirizzi syndrome, and no cystic changes of the bile duct or biloma. Our newly designed C-clip for primary closure of the common bile duct after a choledocholithotomy therefore appears to be beneficial and applicable to clinical patients undergoing traditional as well as laparoscopic surgery.

Bilioenterostomy enhances biliary carcinogenesis in hamsters

The aim of this study was to examine whether the type of bilioenterostomy enhances biliary carcinogenesis in the hamster model. Syrian hamsters were divided into the following groups; simple laparotomy (control group), cholecystoduodenostomy with dissection of the extrahepatic bile duct on the distal end of the common duct (CDDB group) and cholecystoileostomy with dissection of the extrahepatic bile duct on the distal end of the common duct (CIDB group). Following these procedures, all hamsters received N-nitrosobis(2-oxopropyl)amine. The diameter of the extrahepatic bile duct and plasma levels of cholecystokinin (CCK) were measured and the number of neoplastic lesions was counted microscopically. Proliferative effect of the procedures on the biliary epithelium was examined by proliferative cell nuclear antigen. In the CDDB group the extrahepatic bile duct was significantly dilated and carcinogenesis of the gall-bladder and extrahepatic bile ducts was enhanced. In the CIDB group the CCK bioactivity was stimulated and intrahepatic biliary duct, but not gall bladder and extrahepatic bile duct, carcinogenesis was promoted more than that observed in the CDDB group. Proliferation of the biliary duct epithelium was enhanced in both the CDDB and CIDB groups. Cholecystoduodenostomy enhanced intra- and extrahepatic bile duct carcinoma, whereas cholecystoileostomy promoted only intrahepatic bile duct carcinoma. Some factors in the intestinal juice seem to play a role in the promotion of biliary tract carcinoma.

Anionic properties of beta-lactam-enhancing factor on methicillin-resistant Staphylococcus aureus

We found a Factor (factor T) in aged mixtures of tungstate and phosphate which greatly enhanced the antibacterial effects of beta-lactams upon methicillin-resistant Staphylococcus aureus (MRSA). Factor T suppressed penicillinase production and the amount of penicillin-binding protein-2' in the membrane fraction, thus sensitizing MRSA strains to beta-lactams. In addition, Factor T caused a metachromatic reaction and prolonged the blood coagulation time, indicating that it is a heparin-like polyanion. Since Factor T becomes ineffective in the presence of a polycation, a charge interaction may play an important role in the enhancing effect. One possibility is that Factor T non-specifically inhibits several anion-sensitive enzymes. Factor T inhibited several nucleotide-interacting enzymes, but not most serum enzymes.

Synergistic effect of polyoxotungstates in combination with beta-lactam antibiotics on antibacterial activity against methicillin-resistant Staphylococcus aureus

The in vitro antibacterial effect of the combination of various polyoxometalates with beta-lactam antibiotics on methicillin-resistant Staphylococcus aureus (MRSA) strains is investigated by the use of both the National Committee for Clinical Laboratory Standards (NCCLS) disk method and the agar dilution method. Keggin-structural polyoxotungstates such as K7[PTi2W10O40].6H2O (5) and K7[BVW11O40].7H2O (8) and their lacunary species formulated by [XW11O39]n- and[XW9O34]n- potentiated the antibacterial activity of beta-lactam antibiotics such as oxacillin, piperacillin and cefazolin on MRSA with high selectivity. The depression of bacterial growth with the coexistence of polyoxotungstates and oxacillin was confirmed by the measurement of the bacterial turbidity at 660nm. Polyoxomolybdates and polyoxovanadates, on the other hand, exhibited hardly any synergistic effect in combination with oxacillin. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of the membrane proteins separated from MRSA revealed that polyoxotungstates depressed the formation of penicillin-binding protein 2'(PBP2'), an enzyme which is essential for cell wall construction in the MRSA growth. It is concluded that polyoxotungstates make the MRSA strains susceptible to beta-lactam antibiotics.

Effect of genistein on amylase release and protein tyrosine phosphorylation in parotid acinar cells

We evaluated the role of protein tyrosine phosphorylation in amylase exocytosis from parotid acinar cells by using genistein, a tyrosine kinase inhibitor. Amylase release stimulated by isoproterenol was dose-dependently inhibited by genistein. Genistein also inhibited the exocytosis evoked by dibutyryl- or 8-chlorophenylthio-cAMP. Daidzein, a negative control agent of genistein, elicited no inhibitory effect. Isoproterenol had dual effects on protein tyrosine phosphorylation; it increased that phosphorylation of 190- and 210-kDa proteins and decreased that of a 90-kDa one. The phosphorylation was dose-dependently inhibited by genistein but not by daidzein. These results suggest that protein tyrosine phosphorylation plays a role in the process of amylase exocytosis from parotid acinar cells.

Enhancement of biliary carcinogenesis in hamsters by cholecystokinin

We recently developed a new model for rapid and reproducible induction of biliary carcinoma in hamsters. In the present study, we evaluated the effects of cholecystokinin (CCK), which has a trophic action on the gastrointestinal tract and on the pancreaticobiliary system, on biliary carcinogenesis in this hamster model. Hamsters treated with N-nitrosobis (2-oxopropyl) amine (BOP) were divided into four groups: In Group I, hydrolyzed gelatin, a solvent of CCK, was injected subcutaneously. In Groups II and III, CCK 2.5 and 25 microgram/kg were administered, respectively. In Group IV loxiglumide, a CCK receptor antagonist, was administered. CCK significantly promoted the carcinogenetic effect of BOP in the intra- and extrahepatic bile ducts but not in the gallbladder or pancreas. Loxiglumide exerted an inhibitory effect on carcinogenesis in the intrahepatic bile duct.

Successful surgical treatment of secondary Kwashiorkor after total gastrectomy: report of a case

We report herein the case of a 56-year-old woman who developed secondary Kwashiorkor 9 years after undergoing a total gastrectomy for early gastric cancer. Until she began developing the symptoms of Kwashiorkor, including general fatigue, edema of the face and extremities, anemia, alopecia, and weight loss, she had been leading a normal life post-gastrectomy. Her symptoms were alleviated by total parenteral nutrition (TPN) therapy, but reappeared soon after TPN therapy was discontinued. Therefore, she required several subsequent courses of TPN. In an attempt to permanently resolve the ongoing Kwashiorkor symptoms, reconstructive surgery involving transposition of the jejunum from the previous Graham method to the interposition method was performed 10 years after the initial gastrectomy. After the second operation, her malnutrition was completely alleviated, and she has been in good health for the 8 years since. To our knowledge, there has been no other report of the symptoms of secondary Kwashiorkor after total gastrectomy being alleviated by altering the procedure of reconstruction of the intestinal tract. Thus, we recommend surgical treatment to alter the digestive continuity to a more physiological pathway for selected patients with secondary Kwashiorkor syndrome.

[Peripheral T-cell lymphoma with abundant ATL-like cells in the blood]

A 69-year-old woman was admitted to our hospital because of leucocytosis and systemic lymphadenopathy. On admission, white blood cell count was 163,000/microliters, most of which consisted of flower-like cells with convoluted nuclei in the peripheral blood. In the abnormal lymphocyte cells surface-marker test by flow cytometry showed that they expressed CD2, CD3, CD4, CD29, CD45RA, and CD38, but not CD8, CD16, and CD25. Serum anti-Human T-lymphotropic virus type-I (HTLV-I) antibody was negative in particle agglutination, enzyme-linked immunosorbent assay (ELISA) and western-blotting assay. HTLV-I proviral DNA in the abnormal lymphocyte cells was not detected by southern blotting hybridization technique. Moreover, HTLV-I provirus was not detected using a polymerase-chain-reaction (PCR). A monoclonal rearrangement of the TCR-beta chain gene was evident by using DNA probe in southern blot hybridization. Because of the rapid progress of the disease, chemotherapy was started immediately after admission. Though, this patient became refractory, and she died about 1 year after admission.

Insulin-like growth factor-I and transforming growth factor-alpha stimulate differentiation of type A spermatogonia in organ culture of adult mouse cryptorchid testes

This study assessed the effect of growth factors on testicular germ cell differentiation in vitro. Testicular fragments of experimentally prepared cryptorchid testes of adult mice were cultured for 9 days in serum-free media containing various concentrations of IGF-I, TGF-alpha, FGF, and PDGF. Their histology was then examined under a light microscope. Each type of germ cell and mitotic cell in the seminiferous tubules was counted per 1000 Sertoli cells. IGF-I at a concentration of 10 ng/ml induced maximal differentiation of type A spermatogonia. TGF-alpha at concentrations ranging from 1 to 10 ng/ml also stimulated differentiation, whereas FGF and PDGF did not show any stimulation of spermatogonial differentiation in this experimental system.

[Clinical bacteriological analysis of Vibrio vulnificus infection--a report of five case]

Clinical features in Vibrio infection are generally represented by gastrointestinal involvements such as food poisoning, and its prognosis is usually good. However, Vibrio vulnificus infection not uncommonly causes serious problems including sepsis, necrotizing fasciitis of the extremities, and other conditions, sometimes resulting in fatal outcome. In the present study, we analyzed clinical microbiological aspects of five cases with V. vulnificus infection. All the strains of V. vulnificus isolated in five patients are oxidase-positive Gram negative rods presenting comma-like configuration, which were yielded on TCBS agar forming green colonies; they were grayish-white in color and viscous in texture on 5% sheep blood agar, identification of bacteria were done using VITEK AMS (BioMérieux). Piperacillin and third-generation cephalosporins were found to have bactericidal activities against these strains. All five cases we experienced have primary ailments, and three cases out of the five had taken perishable sea-food before showing disease symptoms. V. vulnificus has two infection channels; one is external wound and the other is oral intake. The latter is said that it may become serious. This has a rather short period from the starting the symptoms to death, and there is high death rate. For life-saving, it is inevitably necessary to dose an effective antibacterial medicine in the early stage. If we suspect this bacteria in the test laboratory, it is important to report this to the clinical doctor. In other words, this is one of the bacteria that needs prompt treatment and further microbiology testing.

X-ray evidence for the elongation of thin and thick filaments during isometric contraction of a molluscan smooth muscle

The elongation of thin and thick filaments during isometric contraction of a molluscan smooth muscle was studied by measuring spacing changes of meridional reflections in the medium-angle X-ray diffraction pattern. X-ray patterns from the anterior byssus retractor muscle of Mytilus edulis in the resting, active, and catch states were taken from the same part of a muscle bundle at a fixed specimen-to-detector distance, using imaging plates and 10 s exposure to synchrotron radiation. The third-order reflection (9.2 A) of the axial period of actin, and the fourteenth-order reflection (10.4 A) of the axial subunit-repeat of the thick filament are increased in spacing in the active and catch states. From accurately measured changes in the axial distance of the 9.2 A layer line from the origin, thin filament elongations in the active and catch states are estimated to be 0.48 and 0.32%, respectively, in a muscle that maintains a tension of 12.2 kg cm-2 in the active state and 9.8 kg cm-2 in the catch state. Thick filament elongations in the active and catch states are similarly estimated to be 0.33, and 0.28%, respectively, based on the axial shift of the 10.4 A reflection. The 0.48% elongation of the thin filament in the active state agrees with an elongation that is presumed by White and Thorson (1973) to estimate the lower limit of the thin-filament stiffness. It seems that in the catch state the activated and resting thin filament structures are intermixed. The activated parts of the thin filament are probably more elongated than the apparent value, 0.32%.

Photoreceptor differentiation of retinoblastoma: an electron microscopic study of 29 retinoblastomas

Retinoblastomas exhibit a unique form of differentiation to produce cell elements similar to those seen in a photoreceptor cell. An ultrastructural study was performed on 29 cases of retinoblastoma to further clarify the cytologic characteristics of the tumor cells. The age of the retinoblastomas averaged 17.1 months and the tumor cells showing photoreceptor differentiation were demonstrated in 10 cases (35%). The findings were especially notable in retinoblastomas with Flexner-Wintersteiner rosette formation (seven cases, 28%). Similar photoreceptor differentiation was also evident in solid cell clusters without rosette formation (four cases, 14%). The presence of photoreceptor elements was assumed to be significantly frequent both in Flexner-Wintersteiner rosettes and in the solid cell clusters. The cell cytoplasm also showed proliferation of long mitochondria and microtubules, reflecting photoreceptor differentiation. The hereditary-type retinoblastoma showed more advanced cell differentiation than the non-hereditary type. Photoreceptor differentiated retinoblastoma showed rather indolent growth compared with the undifferentiated type, and the former can expect a curative treatment by operation. These observations provide additional findings of the biological nature of retinoblastomas.

[Why should we measure MIC?]

In actual infectious diseases, bacterial invasion and the effect of antibiotics show "dynamic" behavior, being continuously influenced by various factors. Therefore, "some" knowledge and experience are essential to treat a patient and to make an appropriate decision through only limited information. On the other hand, many patients today still die of infection at the terminal state of illness. Therefore, the importance of "clinical microbiology" has not faded away at all, and will increase much more in the future. However, medical students are not well taught "drug-dynamics" and "how to perform empiric therapy" in the under-graduate curriculum. Thus, such knowledge must be obtained by "self-effort"; i.e., why MIC should be measured, how to make use of MIC for treatment, what the most important information upon treatment of infection is, what moiety is not reflected by MIC, how to judge from which point of MICs, and so on. Furthermore, education or guidance in such fields are not always provided even in the post-graduate training course. To solve these difficulties, we originated a new computer system supporting antimicrobial chemotherapy, which has actually been working well in our hospital from May of 1994. This system is intended to convey maximally the "meaning" of the test results, instead of just reporting only "prosaic" results. In this system, detailed information on various kinds of bacteria and antibiotics is immediately available on every computer monitor. Furthermore, the data base on the average concentration of various antibiotics expected to be reached in each organ by every dose method is already in the system. When MIC actually measured is larger or smaller than such a value, a signal of "untreatable" or "treatable" will appear on the monitor. This is an epoch-making system in Japan, and will help the physicians to provide effective therapy.

Immunohistochemical analysis of EGF in epiphyseal growth plate from normal, hypophysectomized, and growth hormone-treated hypophysectomized rats

Epiphyseal growth plate cartilages from the proximal tibia of normal, hypophysectomized, and growth hormone (GH)-treated hypophysectomized rats were subjected to immunohistochemistry for detection of epidermal growth factor (EGF). In the normal growth plate, EGF was distributed mainly in the proliferative zone. Hypophysectomy resulted in considerable atrophy of the chondrocytes and the cartilage matrix (a decreased number of mature-type chondrocytes and a decreased ratio of proliferating to hypertrophic chondrocytes) and a significant diminution of EGF immunoreactivity. Treatment with GH reversed these effects of hypophysectomy, causing an increased thickness of the growth plate and EGF-reactive sites in all chondrocyte layers. The most intense immunostaining for EGF, however, was frequently seen in the nuclei of chondrocytes with flattened appearance. It appears that EGF could be incorporated or synthesized in chondrocytes having marked mitogenic activity. The present results, taken with previous data on EGF involvement in growth of cartilaginous tissue in vivo and in vitro, strongly suggest that EGF-immunoreactive chondrocytes are involved in cartilage proliferation and growth under the specific influence of GH.