Inactivation of cephamycins by various beta-lactamases from gram-negative bacteria

The enzymic inactivation of cephamycins, i.e. cefoxitin, cefmetazole, cefotetan and cefbuperazone, was investigated by means of bioassay, high pressure liquid chromatography (HPLC) and spectrophotometric analysis using three types of cephalosporinase (CSase, RICHMOND type Ia, Ib and Ic) and one penicillinase (PCase, TEM type). These four cephamycins were not inactivated by Ic CSase and TEM type PCase or producers of these enzymes. However, the inactivation of cefmetazole and cefoxitin was noted when they were incubated in the cultures of CSase (Ia and Ib)-producers or incubated with a large amount of these purified enzymes although the inactivation of cefbuperazone was not noted. HPLC of culture fluid or enzyme solution which contained cefmetazole or cefoxitin and were incubated at 37 degrees C showed that metabolites of cefmetazole or cefoxitin appeared as the drug disappeared. In addition, the appearance of metabolites corresponded to the loss of the drug's bioactivities and the absorption of iodine. UV and IR spectra of cefmetazole which were taken after incubation with the purified CSase showed the cleavage of the beta-lactam ring.

Properties of novel beta-lactamase produced by Bacteroides fragilis

Bacteroides fragilis strains were isolated from clinical specimens. B. fragilis G-237 was highly resistant to beta-lactam antibiotics due to beta-lactamase production. The purified enzyme from this strain gave a single protein band on polyacrylamide gel electrophoresis. The isoelectric point was 4.8, and the molecular weight was estimated to be 26,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme activity was inhibited by p-chloromercuribenzoate and iodine but not by clavulanic acid or sulbactam. The purified enzyme showed a unique substrate profile by hydrolyzing at a high rate most of the cephalosporins, including cephamycin derivatives, penicillins, and imipenem (formerly imipemide, N-formimidoyl thienamycin, or MK 0787).

[In vitro antibacterial activity of cefoperazone]

The in vitro antibacterial activities of cefoperazone (CPZ) against clinical isolates including various beta-lactamase-producing strains were studied and compared with those of cefotiam (CTM). CPZ had a broad spectrum against Gram-negative and Gram-positive bacteria. Especially, CPZ showed apparently more potent antibacterial activities than CTM against Enterobacter cloacae, Serratia marcescens, and Pseudomonas aeruginosa. However, CPZ was less active than CTM against Staphylococcus aureus and Proteus mirabilis. The stability and affinity of CPZ for various types of beta-lactamase were also studied. CPZ was more resistant to hydrolysis by typical cephalosporinase (CSase) and cefuroximase (CXase) than CTM, but was less stable to penicillinase (PCase). CPZ often showed higher affinity to beta-lactamases than CTM. The study for the inducer-activity revealed that CPZ hardly induced CSase production in E. cloacae and Proteus vulgaris while CTM highly induced in both strains. CPZ was more active against CSase-producers than CTM, especially against strains which inducibly produced the enzyme. It was speculated that this activity was responsible for the superior stability to CSase and low inducer-activity for CSase production.

[In vivo antibacterial activity of cefoperazone in intraperitoneal infections in mice]

The in vivo antibacterial activity of cefoperazone (CPZ) against systemic infections was studied in comparison with that of cefotiam (CTM) using beta-lactamase non-producing bacteria and producing bacteria. In vitro antibacterial activity of CPZ against Gram-positive bacteria was slightly inferior to that of CTM, but there was no significant difference between their in vivo activities. On the other hand, the therapeutic effect of CPZ against Gram-negative bacteria was nearly parallel to in vitro antibacterial activity and particularly was superior to that of CTM against cephalosporinase (CSase) producing bacteria. The ascitic levels of CPZ in mice infected with CSase producing bacteria were persisted longer, but those of CTM disappeared quickly after administration. This result appeared to reflect on the therapeutic effects of both drugs.

Constrained nonlinear method for estimating component spectra from multicomponent mixtures

A method is described for estimating the spectra of pure components from the spectra of unknown mixtures with various relative concentrations. This method is based on principal component analysis and a constrained nonlinear optimization technique and is applicable to qualitative analysis of mixtures of more than three components. The method gives two curves as the estimate of a component spectrum: one consists of the set of the maxima and the other consists of the set of the minima for all sampling points subject to a priori information. Experimental results of the estimation of the infrared absorption spectra of xylene-isomer mixtures are shown; the noise problem with this method is also discussed.

Superresolution of Fourier transform spectroscopy data by the maximum entropy method

The maximum entropy method (MEM) is applied to the interferogram data obtained using the technique of Fourier transform spectroscopy for estimating its spectrum with a resolution far exceeding the value set by the spectrometer. For emission line data, the MEM process is directly used with the interferogram data in place of the regular Fourier transformation process required in Fourier transform spectroscopy. It produces a spectral estimate with an enhanced resolution. For absorption data with a broad background spectrum, the method is applied to a modified interferogram which corresponds to the Fourier transform of the absorptance spectrum. Two results are presented to demonstrate the power of the technique: for the visible emission spectrum of a spectral calibration lamp and for the infrared chloroform absorption spectrum. Included in the paper is a discussion of the problems associated with practical use of the MEM.

Median raphe- and contralateral hippocampus-elicited EEG spikes which correspond to hyperpolarizations of pyramidal cells in the kindled hippocampus of the rabbit

Rabbit hippocampus was chronically stimulated with implanted electrodes until interictal EEG spikes were kindled in it. The kindled hippocampus was then studied in acute experiments. Stimulation of the median raphe nucleus and that of the opposite hippocampus produced EEG spikes, whose intracellular correlates were hyperpolarizations of pyramidal cells (referred to as inhibitory EEG spikes).

[Hyperparathyroidism after radioactive iodine therapy for Graves' disease: a case report]

Herein we report a 36-year-old man with hyperparathyroidism and a past history of internal irradiation to the thyroid. Twelve years previously at age 24 years he had received 8 mCi of radioactive iodine for Graves' disease. An additional dose of 4 mCi was required 3 years later. A right lower parathyroid adenoma (28 X 23 X 20 mm, 5.7 g) was found at neck exploration. Although the association of external ionizing radiation to the head and neck and the subsequent development of hyperfunctioning parathyroid glands has been described in recent years, there are only 4 cases in the literature of parathyroid surgery for hyperparathyroidism secondary to earlier treatment with radioactive iodine for Graves' disease. In a long-term follow-up of 180 patients treated with radioactive iodine for Graves' disease, neither hypercalcemia nor hypophosphatemia was found. Whether internal radiation therapy can be a causative factor in the development of hyperparathyroidism should be elucidated in future. However, it seems reasonable to suggest that patients whose hyperthyroidism has been treated with radioactive iodine should have their serum calcium levels examined at 5-year intervals.

Two monoclonal antibodies detecting allotypic determinants of HLA-A

Three mouse hybridomas producing cytotoxic antibodies against HLA were established. By standard microcytotoxicity test against panels of normal controls, the antigen defined by MA-9 antibody (IgM) showed a good correlation with HLA-A9 alloantigen detected by conventional typing alloantisera (r = 1.0). Family studies also showed that MA-9 determinant segregated with HLA-A9. MA-10 antibody (IgM) reacted with all HLA-A10 positive lymphocyte donors and cross-reacted with two thirds of HLA-AW33 positive donors. Ml-1 antibody (IgG2a) reacted with all the panel cells tested and immunoprecipitated a molecule of 43,000 daltons from Nonidet P-40 lysates of 3H-glucosamine-labelled cells. The results showed that MA-9 and MA-10 antibodies can be used as routine tissue typing reagents.

Induction of cephalosporinase production by various penicillins in enterobacteriaceae

The inducer activity of seven penicillins for cephalosporinase (CSase) production and their antibacterial activity against CSase-producing strains were studied using clinical isolates of Proteus morganii, P. rettgeri, P. vulgaris, Enterobacter cloacae, and Serratia marcescens. Piperacillin, apalcillin, and methicillin showed rather low inducer activity for CSase production in all strains tested. On the other hand, ampicillin, carbenicillin, and sulbenicillin showed high inducer activity for CSase production. Piperacillin, apalcillin, and ampicillin were less stable to CSases than were carbenicillin, sulbenicillin, and methicillin, but much more stable than benzylpenicillin. In the growing culture of CSase-producing strains, piperacillin and apalcillin were rather stable. Against CSase-producing strains, piperacillin and apalcillin were more active than other penicillins tested.

Antibacterial activity of cefoperazone alone and in combination against cephalosporinase-producing Enterobacter cloacae

The activity of cefoperazone against a strain with an inducible cephalosporinase and a mutant that produces the enzyme constitutively indicates that the low inducer activity of this antibiotic plays an important role in its activity against Enterobacter cloacae.

A highly sensitive pyrogen test for antibiotics I: detection of trace amounts of endotoxin in injectable sodium ampicillin preparations

The rabbit pyrogen test (specified in the pharmacopeia) and the Limulus amebocyte lysate (LAL) test are influenced by high concentrations of certain antibiotics. Therefore, it has not been possible to detect trace amounts of endotoxin which may contaminate these antibiotics. To detect trace amounts of endotoxin in injectable sodium ampicillin, an ultrafiltration technique was utilized which removed the antibiotic and left a solution which contained predominantly the endotoxin. After ultrafiltration, a trace amount of pyrogen (which otherwise could not be detected) was found using both the rabbit pyrogen and the LAL tests. The endotoxin was also determined quantitatively using a chromogenic endotoxin reagent which is made by combining the Limulus amebocyte lysate and a synthetic substrate with a suitable chromophore.

Serological analysis of cell surface antigens of HL-60 cells before and after treatment with a phorbol ester tumor promoter

The human HL-60 cell line derived from acute promyelocytic leukemia, consisting of promyelocytic type of cells, was able to differentiate into adherent cells with monocytemacrophage features by the treatment with 12-0-tetradecanoyl phorbol-13-acetate (TPA). Cell surface antigens of HL-60 cells before and after TPA treatment were studied with monoclonal antibodies and four hybridoma clones producing IgM antibodies were established. Two antibodies (HL-21 and HL-47) reacted only with the immunizing TPA-treated HL-60 cells, and HL-1 antibody produced against untreated cells was reactive with both TPA-treated and untreated cells, but HL-5 antibody reacted predominantly with the immunizing untreated cells. Serological reactivity against various types of normal hematopoietic cells and acute leukemias (diagnosed by the French-American-British classification) was studied by immune adherence assay and immuno-electron microscopy. HL-21 antibody was reactive with monocytes and most cases of M4 and M5 types of acute non-lymphocytic leukemia cells. HL-47 antibody did not react with the cells of myelocyte-monocyte lineage or mature lymphocytes, but it did react with one-third of acute lymphocytic leukemia (L1 and L2) cases. Since all HL-47+ cases were included in the group of common ALL antigen positive cases, it was estimated that HL-47 is a differentiation antigen present on lymphocyte precursors, from which null-cell type acute lymphocytic leukemia cells generally originate. HL-1 antibody reacted with the cells of myelocyte-monocyte lineage as well as those of most acute non-lymphocytic leukemias. HL-5 antibody reacted with granulocytes and M2 type of acute myelocytic leukemia cases, and also with M5 type of acute monocytic leukemia cases. Serological studies of these antibodies revealed that TPA can induce to differentiate HL-60 cells not only into HL-21+ macrophage-like cells, but also into HL-47+ lymphoid stem cells. In addition, these antibodies were demonstrated to be very valuable for differential diagnosis of acute leukemias.

Enhancement of EEG spikes and hyperpolarizations of pyramidal cells in the kindled hippocampus of the rabbit

EEG spikes and their intracellular correlates were studied in both normal and kindled hippocampi (i.e., the hippocampi subjected to daily electrical stimulation) of rabbits. Many of the EEG spikes observed were referred to as inhibitory EEG spikes, because their intracellular correlates were hyperpolarizations of pyramidal cells. In most cases, these hyperpolarizations occurred without any preceding spikes, but could be led by a single spike. They were, however, never preceded by a spike burst. Inhibitory EEG spikes occurred in both normal and kindled hippocampi. In both cases, they not only appeared spontaneously, but were also induced by brain stem stimulation. Regardless of whether they appeared spontaneously or were induced by stimulation, the inhibitory EEG spikes and the corresponding hyperpolarizations were much larger in magnitude in the kindled than in the normal hippocampus. Consequently, it was concluded that enhancement of inhibition was one of the features of the kindled hippocampus.