Oxygen uptake rate of immobilized growing hybridoma cells

Summary The specific oxygen uptake rate of hybridoma cells immobilized in calcium alginate gel particles was measured, and the observed data was compared with those of non-immobilized cells. The uptake rate of the immobilized cells coincided with that of the non-immobilized hybridoma cells just after immobilization, but increased with cell growth. On the other hand, the cellular glucose consumption rate decreased slightly during the experiments. The increased oxygen uptake rate by immobilized cells was closely related to the formation of cell colonies in the gel particles.     

The genotoxicity of a variety of aniline derivatives in a DNA repair test with primary cultured rat hepatocytes

The genotoxicity of a variety of aniline derivatives was examined by a DNA repair test with rat hepatocytes. Out of 37 aniline derivatives, 6 chemicals, i.e., 2,4,6-trimethylaniline (mesidine), 2,4-xylidine, 3,5-diaminobenzoic acid, 3,4-diaminochlorobenzene, 2-chloro-4-methylaniline and 4-chloro-N-methylaniline, elicited positive DNA repair responses. The results are in agreement with the bacterial mutagenicities with or without norharman of these compounds. Positive compounds of unknown carcinogenicity in the present assay, i.e., 3,5-diaminobenzoic acid, 2-chloro-4-methylaniline and 4-chloro-N-methylaniline are suspected of being potentially carcinogenic.     

Comparative effects of a recombinant and a mutein type of granulocyte colony stimulating factor on the growth of Meth-A fibrosarcoma with 5-fluorouracil chemotherapy

The present study was designed to evaluate the effects of a recombinant human G-CSF (rhG-CSF) and a mutein G-CSF(KW-2228) on leucopenia and tumor growth in mice treated with 5-fluorouracil (5-FU). In normal mice, the number of leucocytes (white blood cell, WBC) reached the peak 12 hours after a single injection of either type of G-CSF and decreased to the normal level after 24 hours. Daily administration induced a continuous increase in the WBC count, however, administrations at intervals did not. Meth-A fibrosarcoma was subcutaneously inoculated into the backs of syngeneic BALB/c mice. The mice were treated with 5-FU alone or with G-CSFs. Chemotherapy with 5-FU alone resulted in leucopenia and an insignificant inhibition of tumor growth. The conjunctive administration of G-CSFs with 5-FU resulted in a significantly augmented inhibition of tumor growth, and leukopenia was not seen. This augmenting effect was more prominent with KW-2228.These results suggest that in 5-FU chemotherapy G-CSFs may be beneficial in restoring the number of leucocytes from leucopenic state and in augmenting the tumor inhibitory effect. Furthermore, KW-2228 may be more beneficial than the natural type rhG-CSF.     

Long-term cultivation of anchorage-independent animal cells immobilized within reticulated biomass support particles in a circulating bed fermentor

Summary Long-term cultivation of anchorage-independent animal cells immobilized within porous biomass support particles (BSPs) using a gas-stirred circulating bed fermentor (CBF) was investigated. Inoculation of mouse myeloma MPC-11 (ATCC CCL 167) cells into reticulated polyvinyl formal resin BSPs (3 × 3 × 3 mm; mean pore diameter, 60 m; porosity, 0.88) and the repeated batch culture of inoculated cells were performed under gentle circulation of BSPs, induced by sparging air from the base of the fermentor. The glucose uptake rate of cells decreased in the initial period just after the start of circulation, since a relatively large number of cells leaked from the BSPs. After that period, the uptake rate gradually increased and the leakage of cells diminished. In the meantime, when inoculated cells were incubated statically by introducing air into the upper part of the fermentor for the initial several days before circulating the BSPs, glucose consumption became very rapid and cell density in the BSPs reached at least 10⁷ cells/cm³ BSP. Thus, a long-term cultivation without significant leakage of cells and with high cell density in BSPs was successfully achieved in the CBF-BSP system.Offprint requests to: H. Yamaji     

Two monoclonal antibodies against small-cell lung cancer show existence of synergism in binding

Summary Murine IgG1 monoclonal antibodies (mAbs), ITK-2 and ITK-3, were generated against a small-cell lung cancer (SCLC) cell line. Enzyme-linked immunosorbent assay using a variety of established cell lines as substrates, immunoperoxidase staining of freshly frozen tissue sections, and fluorescence-activated cell sorter analysis of peripheral blood leukocytes showed that these mAbs recognize a part of the SCLC-associated cluster 1 antigen. In immunoprecipitation studies, both ITK-2 and ITK-3 bound to a 145-kDa glycoprotein of SCLC cell membrane extracts, as did MOC-1 and NKH-1, which both recognize the cluster 1 antigen. However, because the binding of¹²⁵I-labeled ITK-2 to SCLC cells was not inhibited by MOC-1 or NKH-1, the binding site of ITK-2 on SCLC cells appeared to be different from that of either MOC-1 or NKH-1. Unexpectedly, binding of¹²⁵I-labeled ITK-2 to SCLC cells increased in the presence of ITK-3. This ITK-3-induced increase in ITK-2 binding was due partly to an increase in the number of binding sites for ITK-2 on SCLC cells. Addition of ITK-3 may, therefore, improve the effectiveness of ITK-2-based tumor detection or therapy.     

Incorporation of fatty acids by Streptococcus mutans

In a series of investigations into the cariogenicity of Streptococcus mutans, we studied the incorporation of exogenous fatty acids with reference to glucosyltransferase secretion and membrane fatty acid changes. When cells were grown with different fatty acids, both saturated and unsaturated fatty acids were readily incorporated into the membrane lipids and were biotransformed and elongated preferentially to the longer 16- and 18-carbon-chain fatty acids. This incorporation and chain-elongation led to significant changes in fatty acids composition. By adding fatty acids to the medium, it was possible to appropriately modify the degree of unsaturation and the relative ratio between specific fatty acids in the membrane lipids of S. mutans.     

On the hoplonemertean Sagaminemertes nagaiensis (Iwata, 1957), with consideration of its systematics

Summary The polystiliferous hoplonemertean Sagaminemertes nagaiensis (Iwata, 1957) has been redescribed.A distinct pre-cerebral region is wanting. The rhynchocoel opens directly at the tip of the head, whilst the mouth opens seperately below the ventral commissure of the brain which is situated at the anterior end of the head. The dorsal ganglia are well developed and extend posteriorly far behind the ventral ganglia. The cerebral sense organs are situated behind the brain and possess posterior ciliated canals. Cephalic glands are poorly represented, but ocelli are well developed. The sickle-shaped basis of the proboscis bears about 20 central stylets. The caecal appendages of the rhynchocoel are arranged pseudometamerically throughout the body. The foregut is straight, consisting of mouth, oesophagus, stomach and pylorus. Intestinal caeca and lateral diverticula are present. The cephalic lacunae have no anterior anastomosis. A cerebral lacuna is present, there is a rhynchocoel vessel, but transverse vessels are absent. The protonephridia extend throughout the foregut region. Mature spermatogonia are well developed.A systematic discussion of Sagaminemertes nagaiensis suggests that it is taxonomically close to Siboganemertes weberi in the archireptantic family Siboganemertidae.     

Difference in phospholipid dependence between two isozymes of brain (Na+ + K+)-ATPase

The effect of phospholipase C on two isozymes (alpha (+) and alpha forms) of rat brain (Na+ + K+)-ATPase and the temperature-dependence of their activities were investigated. Phospholipase C from Clostridium welchii inhibited the activities of the enzymes treated with and without pyrithiamin or N-ethylmaleimide, a preferential inhibitor of the alpha (+) form, but the extent of the inhibition was higher in the control enzyme than in the treated enzymes. The treatment of the (Na+ + K+)-ATPase with phospholipase C altered a ratio between high- and low-affinity components for ouabain inhibition. It also caused the similar change in a ratio between the alpha (+) and alpha forms of Na+-stimulated phosphorylation from [gamma-32P]ATP. These findings indicate that the alpha (+) form of rat brain (Na+ + K+)-ATPase is more sensitive to phospholipase C than the alpha form. Analysis of Arrhenius plots of the activities of the control and pyrithiamin-treated enzymes showed that there was a difference between the two enzymes in a break point. We suggest that two isozymes of rat brain (Na+ + K+)-ATPase differ in the interaction with phospholipids or in the lipid-environment.     

Pathological study on nephrocalcinosis in Fischer 344/Du Crj rats

Histopathological examinations on nephlocalcinosis of the Fischer 344 (F344) rats were carried out. As the results of comparison on its appearance among F344, Wistar and SD strains of rats, F344 female rats showed the most severe nephrocalcinosis. Nephrocalcinosis developed between 4 weeks and 8 weeks and was likely to keep its appearance through 108 weeks of the survival period of the rats. Histologically, mineral deposit was always observed at cortico-medullary junction. It seemed to locate at the outer portion of the basement membrane of the tubular epithelium, adjacent to the capillary wall in the connective tissue. Four weeks after ovariectomy at 4 weeks of age, the rats showed a decrease in degree of nephrocalcinosis. In contrary, the rats treated with estorone following ovariectomy revealed an increase in degree of nephrocalcinosis. It was suggested that the oestrogen-type sex hormone appeared to give a role in nephlocalcinosis.