Accumulation of platinum in the intervertebral discs and vertebrae of ovarian tumor-bearing patients treated with cisplatin

Platinum was determined by the inductively coupled plasma mass spectrometry (ICP-MS) in the intervertebral discs and vertebrae of ovarian tumor bearing patients treated withcis-diamminedichloro-platinum (II) (cisplatin). Platinum was 0.05 ng/mL at the absolute detection limit, and platinum was undetectable in the intervertebral discs and vertebrae of human specimens without cisplatin treatments. On the other hand, platinum was detected in the intervertebral discs and vertebrae of patients administered cisplatin, and platinum concentration was at levels of 1.06–10.31 μg/g dry tissue in the intervertebral discs and 0.60–1.28 μg/g dry tissue in the vertebrae, respectively. The platinum level of intervertebral discs was 4.3-fold higher than that of the vertebrae. Thus, platinum accumulates greatly in the intervertebral discs and somewhat in the vertebrae after administering cisplatin to patients for therapy.     

Effects of dietary lactose and purified diet on intestinal microflora of rats

In the rats fed on lactose-containing purified diet (PDL), bifidobacteria remarkably increased in number in both the jejunum and cecum as compared with those fed on control diet (PD) or conventional diet (NMF). Besides, lactobacilli, streptococci, staphylococci, and Escherichia coli increased in number in the jejuna and/or ceca of rats fed on PDL as compared with those fed on PD. The incidence and numbers of Lactobacillus species were remarkably different between the rats fed on PDL and those on any of the other diets. Indole-producing Bacteroides spp. were rarely isolated from the PDL-fed rats. The cecum was markedly enlarged in the PDL rats and reduced in the PD rats as compared with that in the NMF animals.     

Analysis and simulation of networks of mutually inhibiting neurons

Networks of mutually inhibiting neurons are analyzed and simulated on a digital computer. In the analysis and simulation a continuous-variable model of the neuron is used as the basic element. It consists of a many-input adder, a first-order low-pass filter and a diode-type nonlinearity. A mutually inhibiting network is formed by connecting the output of every element to inputs of the other elements through weight-coefficient setting units. Each element of the network is assumed to receive a certain number of constant inputs from elements of other networks.An autonomous system of nonlinear differential equations is introduced to describe the network dynamics, and the steady-state solutions of the system are investigated in detail. The network has a unique equilibrium solution, multiple equilibrium solutions or a periodic solution depending on the weight-coefficients and the inputs. It is shown that these three cases correspond to three types of information processing functions: the sharpening of input patterns, the temporary storage of information and the generation of periodic signals.     

A comparison of the effects of cationic, anionic, and neutral amphipathic agents on the contractile behaviour of frog skeletal muscle. I. Twitches and potential threshold for contraction

Cationic, anionic, and neutral amphipathic agents displayed striking differences as well as similarities in their effects on the contractile function of frog skeletal muscle. Slowed repolarization during the action potential appeared to account for twitch potentiation by low concentrations of alkyl trimethylammonium and by small n-alkanols (propanol, butanol). Small n-alkanols also caused a decrease in the potential threshold for K contractures and slower relaxation of submaximum K contractures as well as enhancement of chloride withdrawal and caffeine contractures, but these effects were not observed with larger alkanols. For the ionic amphipathic agents, the direction of the changes in the relation between Ko and K-contracture tension could be accounted for on the basis of the expected changes in surface charge, but the effects of these two types of agents on the rate of relaxation of submaximum K contractures were disproportionate and with the cationic series were opposite in direction to those produced by inorganic divalent cations. The reductions in the amplitude of chloride-withdrawal contractures by cationic as well as anionic amphipaths indicated that both types of agents can impair excitation-contraction coupling. Similar depressant effects on caffeine contractures demonstrate that these responses also can be influenced by events restricted to the external lamina of the sarcolemma. It is concluded that opposite effects can be produced by similar perturbations in different regions of the sarcolemma and that electrostatic as well as hydrophobic interactions can make an important contribution to the effects of amphipathic agents on twitches and contractures in skeletal muscle.     

Electrical pacing in the gastroduodenal junction area of conscious dogs (author's transl)]

To determine whether the electric activities of the stomach and duodenum are related, the gastroduodenal junction area of the stomach of dogs was paced through implanted bipolar silver electrodes. It was found that the pacing rate of the basic electrical rhythm (BER) in the antrum of the stomach could be increased to a maximum of 8.9 cycles/min, without affecting the BER frequency in the duodenum. Conversely when the pacing rate of the BER in the duodenum was increased to a maximum of 24 cycles/min, the BER frequency in the antrum remained unaffected. These results show that the BER in the stomach and duodenum are independent, and imply that the BER cycles in the stomach and duodenum are due to the presence of two independent pace-maker areas.     

Protocols for two- and three-color fluorescent RNA in situ hybridization of the main and accessory olfactory epithelia in mouse

Brain Cell Biology - The main and accessory olfactory epithelia of the mouse are composed of many cell populations. Each sensory neuron is thought to express one allele of one of the ～1000...     

Retarded recovery of excitability and twitches of frog toe muscles after K-induced depolarization (slow inactivation) in the presence of alkyl amphipaths

Alkyl amphipaths resemble conventional local anesthetics in their ability to retard the recovery of excitability and twitch tension after depolarization at high Ko, an effect that is attributed to slow inactivation of potential-dependent sodium channels. The similar effect of low temperature offers an explanation for its ability to enhance the frequency-dependent effects of these agents.