A microflow superfusion system for use with excised membrane patches

A new method for rapidly changing the solution superfusing excised membrane patches is described. The main advantage of this method over previous rapid exchange methods is that it is possible to use very small quantities of solution (minimal volume about 100 l). The method consists of inserting the pipette tip, after obtaining an excised patch, into a small tube which can be independently perfused. Air bubbles are used to separate different solutions and to produce rapid step changes of solution. To test this method we examined the rate of change of: (1) the pipette resistance produced in response to changing to a solution of lower conductivity, (2) the amplitude of single K-channel currents in response to changing external K. The results suggest that the solution exchange is essentially a step function and is complete within 10–20 ms. The recording is briefly interrupted during the time taken for the passage of the air bubble past the pipette tip (<250 ms). In general, the passage of the air bubble did not affect the seal resistance. This method will be particularly useful for studies of the interactions of single ionic channels with chemicals which can only be obtained in small quantities.     

Temporal feature of BOLD responses varies with temporal patterns of movement

Which brain sites represent the final form of motor commands that encode temporal patterns of muscle activities? Here, we show the possible brain sites which have activity equivalent to the motor commands with functional magnetic resonance imaging (fMRI). We hypothesized that short-temporal patterns of movements or stimuli are reflected in blood-oxygenation-level-dependent (BOLD) responses and we searched for regions representing the response. Participants performed two temporal patterns of tapping and/or listened to the same patterns of auditory stimuli in a 3T fMRI. The patterns were designed to have the same number (11) of events and the same duration, but different temporal distribution of events. The 11 events were divided into two parts (10 repetitive taps and one stand-alone tap) and the interval of the two parts was 3s. The two patterns had reverse order of the two parts. The results revealed that different temporal patterns of auditory stimuli were represented in different temporal features of BOLD responses in the bilateral auditory cortex, whereas different temporal patterns of tapping were reflected in contralateral primary motor cortex and the ipsilateral anterior cerebellum. In bilateral premotor cortex, supplementary motor area, visual cortex, and posterior cerebellum, task-related BOLD responses were exhibited, but their responses did not reflect the temporal patterns of the movement and/or stimuli. One possible explanation is that the neuronal activities were similar for the two patterns in these regions. The sensitivity of the BOLD response to the temporal patterns reflects local differences in functional contributions to the tasks. The present experimental design and analysis may be useful to reveal particular brain regions that participate in multiple functions.     

Spinal commissural neurons mediating vestibular input to neck motoneurons in the cat upper cervical spinal cord.

Spinal commissural neurons (CNs) activated di- or trisynaptically by stimulation of ipsilateral vestibular afferents were stained with intraaxonal injection of horseradish peroxidase in the cat upper cervical spinal cord. Stem axons of CNs in lamina VIII or VII, after crossing the midline, had ascending and/or descending main branches that gave off multiple axon collaterals to laminae IX and VIII over a few cervical segments. Terminal boutons appeared to make contact with proximal dendrites and somata of retrogradely-labelled neck motoneurons. Therefore, these CNs were regarded as mediating vestibular afferent input to contralateral neck motoneurons trisynaptically at the shortest.     

The Significance of Low Serum Pepsinogen Levels to Detect Stomach Cancer Associated with Extensive Chronic Gastritis in Japanese Subjects

Serum pepsinogen levels were measured in 137 stomach cancer patients and compared with those of 288 normal cancer-free subjects. The serum pepsinogen levels of stomach cancer patients, especially pepsinogen I and the pepsinogen I/pepsinogen II ratio were significantly lower than those of normal controls and correlated well with the extent of chronic gastritis associated with the cancerous stomach. These results were in good accordance with the results of previous studies indicating that the cancer derived from the stomach where chronic gastritis/intestinal metaplasia is extensive. The high sensitivity and specificity of this non-invasive serum test to detect chronic gastritis suggested the possibility of its application to the mass screening of stomach cancer.     

The ATP- and tolbutamide-sensitivity of the ATP-sensitive K-channel from human pancreatic B cells

Summary The ATP- and sulphonylurea-sensitivity of the ATP-sensitive K-channel was measured in human pancreatic B cells. In inside-out patches, half-maximal inhibition of channel activity was produced by 10 mol/l ATP (with 2 mM Mg²⁺) and ATP-inhibition was partially antagonised by ADP. A significantly lower sensitivity to ATP was found in whole-cell recordings. Tolbutamide inhibited whole-cell ATP-sensitive K-currents half-maximally at 18 mol/l; the sensitivity to tolbutamide was somewhat less in the inside-out patch. Ca-activated K-channels were unaffected by tolbutamide (10 mmol/l). These results resemble those found for rodent B cells and suggest that sulphonylureas exert their therapeutic effects in Type 2 (non-insulin dependent) diabetes by inhibition of the ATP-sensitive K-channel.     

Renal accumulation of technetium-99m-labeled bone imaging agents in patients treated with cisplatin

As the routine follow-up studies in patients with malignant diseases, bone scintigraphy is often performed to detect bone metastasis, before, during and/or after the treatments. Among these patients who were treated, especially, with CDDP, we often encountered the markedly increased renal radioactivity during the follow-up period by bone scintigraphy. In this study, 68 patients with 76 bone scintigraphy performed within 30 days after the administration of CDDP were evaluated. Forty-five of the 76 bone scintigraphy (60.5%) in the 68 patients exhibited more prominent accumulation of the radionuclide in the kidneys than that normally seen. Among them, twenty-four cases (31.6%) showed markedly increased accumulation of the radionuclide in the kidneys so called the "hot kidneys", when the bone scintigraphy was performed later than 3 weeks after the treatment with CDDP. Moreover, the frequency of the "hot kidneys" were well correlated with the degree of renal damage in terms of serum creatinine levels. These findings suggest that the "hot kidneys" might represent the presence of transient renal damage caused by the administration of CDDP. As the causes of this finding called as the "hot kidneys", various factors and/or many causes are reported recently, however, the highest incidence of this phenomenon is thought to be occurred by CDDP as the factor of drug incidence.