Two mouse monoclonal antibodies (MoAbs), B10 and 1H5, were generated by fusing mouse myeloma NS-1 cells with spleen cells from a BALB/c mouse immunized with Ueda-1 cells derived from human squamous cell carcinoma (SCC) of the floor of the mouth. Immunohistochemical analysis revealed that these MoAbs recognize the filamentous components of cytoplasm which were protein in nature. While the pattern of antigen distribution in various cell lines was not cell-type specific, reactivity of these antibodies with tissue sections was informative. MoAb 1H5 was preferentially reactive with well-differentiated squamous cell carcinoma, however, reaction with adenocarcinoma was observed infrequently. This antibody also preferentially reacted with the spinous layer of normal stratified squamous epithelium. MoAb B10, however, was reactive with nonepithelial tissues as well as with epithelial ones, and its level of binding bore no relationship to the grade of histologic malignancy. SDS-PAGE and Western blotting analysis, using cytokeratin extracts of Ueda-1 cells and human epidermis, demonstrated that MoAb B10 reacted with a wide range of keratin proteins of 65-67K, 58K, 56.5K, 56K, 52K, 50K, 48K, 45K, 40K, 38K, 36K, and 34K molecular weight (MW), while MoAb 1H5 reacted with keratin proteins of 65-67K, 58K, 56.5K, 56K, 52K, 48K, and 34K MW. These results suggest that MoAb 1H5 may recognize keratin subfamilies related to squamous differentiation, whereas MoAb B10 recognizes a wide range of keratin proteins, and may even react with other kinds of intermediate filament proteins (IFPs).

Antibodies, Monoclonal↗

PubMed1987

Kinetics of hepatic transport of 4-methylumbelliferone in rats. Analysis by multiple indicator dilution method.

Hepatic elimination of 4-methylumbelliferone (4-MU), which has been used as a model compound for conjugative metabolism, was studied by means of a multiple indicator dilution (MID) method in the isolated perfused rat liver. Using this method, three intrinsic hepatic clearances, CLint,inf, CLint,eff, and CLint,seq, which represent the influx, efflux, and sequestration processes, respectively, were obtained. When the dose was increased from a low dose (50 micrograms/rat liver) to a high dose (3000 micrograms/rat liver), the hepatic availability of 4-MU increased from 0.11 to 0.73. With increasing dose, the CLint,eff value increased approximately two times, while the CLint,seq value decreased to approximately one-third. The remarkable dose dependence of hepatic availability was due to nonlinearity in both CLint,eff and CLint,seq values. However, the CLint,inf value was almost independent of dose. The dose-dependent change in CLint,seq might be explained by the saturation of conjugative metabolism of 4-MU, while the increase in the CLint,eff value with increasing dose might be partly explained by the nonlinear tissue binding of 4-MU, since the tissue unbound fraction determined by an ultrafiltration method using liver homogenate increased approximately 1.5 times at higher concentration of 4-MU compared to that at lower concentrations. In addition, based on a comparison of the individual intrinsic clearances, i.e., CLint,inf, CLint,eff, and CLint,seq, the major determining process of the apparent hepatic intrinsic clearance of 4-MU is thought to be the sequestration process at the high dose. However, at the low dose, the membrane transport process (influx and efflux processes) as well as the sequestration process also determine the apparent hepatic intrinsic clearance.

Animals↗

PubMed1987

Effect of a diffusional barrier to a metabolite across hepatocytes on its kinetics in "enzyme-distributed" models: a computer-aided simulation study.

The effect of a diffusional barrier to a metabolite between the blood and hepatocytes on elimination kinetics of formed and preformed metabolites was predicted under various enzymic distributions in the liver by computer-aided simulation. Sequential metabolism by which the primary metabolite (MI) is generated from the parent drug (D) and further metabolized to the terminal metabolite (MII) by enzymes A and B, respectively, was chosen for the simulation. Moreover, four models of enzyme distribution patterns were defined with regard to the hepatic blood flow path. The extraction ratios for the preformed and formed metabolites (designated as Em and Ep----m, respectively) were simulated by varying both the average intrinsic clearance of enzyme B (CLint,B) and the permeability of hepatocytes for MI (Pm), while keeping the average intrinsic clearance of enzyme A (CLint,A) equal to hepatic blood flow (Q). When a rapid equilibrium of MI between the blood and hepatocytes held, i.e., Pm was large relative to Q, Em was equal to or higher than Ep----m for all models, as previously shown by Pang and Stillwell. By contrast, it was found that when a diffusional barrier for MI existed, i.e., Pm was small relative to Q, Em was equal to or lower than Ep----m. Furthermore, it was observed that the smaller Pm became, the larger the difference between Em and Ep----m became. We further simulated the effect of the intrinsic clearance (CLint,C) for a metabolic pathway, which competes for that by enzyme A, on the Ep----m value. In the model assuming even distribution of all the enzymes along the flow path, irrespective of the CLint,C value, a similar effect of Pm on Ep----m was observed when the Pm value was relatively small (Pm less than Q). By contrast, in the case of uneven enzymic distributions of enzymes A and B, the effect of the CLint,C value on the relationship between Pm and Ep----m occurred to some extent. From these simulations, it was concluded that lower membrane permeability (Pm) both diminishes the entry of preformed metabolite into the hepatocytes and accelerates the removal of intracellularly formed metabolite (through sequential metabolism) by diminishing its efflux, yielding lower Em than Ep----m. When Pm becomes small (Pm less than 1/10Q), these mechanisms for lower Em than Ep----m predominate over other mechanisms such as the presence of a competing metabolic route and uneven distribution of enzymes.

Biotransformation↗

PubMed1987

Electrophysiological evidence for dreaming: human cerebral potentials associated with rapid eye movement during REM sleep.

In order to examine the relationship between rapid eye movement (REM) during REM sleep and dreaming, scalp EEGs (Fz, Cz, Pz and Oz) of 4 normal human subjects, time-locked to REM onset, to saccade onset toward fixation targets and to saccade onset in total darkness, were averaged. The results include the following: Three positive potentials were associated with REM: a sharp potential in the parieto-occipital area just before REM onset; a large, slow potential in the vertex area 140-180 msec after REM onset; and a potential in the occipital area 210-280 msec after REM onset. Three positive potentials, one being the so-called EM-antecedent potential and the others being the lambda response, were associated with the waking saccades toward targets: a sharp potential in the parieto-occipital area just before the saccade onset and two potentials in the occipital area with latencies of 140-150 and 260-310 msec from the saccade onset. Only the EM-antecedent potential appearing just before saccade onset was found in association with saccades in total darkness. The similarities between the 3 positive potentials during REM sleep and the lambda response during wakefulness, and the relationship between those potentials and dreaming, are discussed in terms of the neural processes occurring during REM sleep.

Action Potentials↗

PubMed1987

Epidermal Langerhans cells undergo mitosis during the early recovery phase after ultraviolet-B irradiation.

We studied the recovery phase of immune response-associated (Ia)-positive or ATPase-positive epidermal Langerhans cells (ELCs) after ultraviolet B (UVB)-induced depletion by using mouse ear epidermal sheets. An area 3 mm in diameter was irradiated with 300 nm UVB light (40 mJ/cm2). A time sequence study was carried out to 56 days. During this period the Ia-positive ELC population increased stepwise, i.e., first a rapid increase between day 7 and day 14, which we called the early recovery phase, and next a gradual increase between day 42 and day 56, which we called the late recovery phase. During the early recovery phase, we found polymorphous ELCs in the irradiated area which were giant or normal in size, dendritic or round in shape, and single or paired in distribution. Electron microscopy revealed some of round and some of paired ATPase-positive ELCs to be in metaphase or telophase of mitotic division. Within the entire observation period of our study, there was no evidence suggesting migration of ELCs from hair follicles or from the nonirradiated epidermis. These findings indicated that mitosis of ELCs contribute to their repopulation during the early recovery phase.

Animals↗

PubMed1987