Biomedical subjects
Publications and source records attributed to X Z Xu.
When glass insulating tungsten microelectrodes are made, the insulating glass is usually drawn apart at an earlier than desired moment leaving a longer uninsulated metallic tip. A simple method for removing the excessively protruded part of the tungsten tip and triming it to any desirable length and shape is described.
Bi-unit recordings were sometimes obtained in the lateral geniculate nucleus of cat with a single microelectrode. The neuron pairs consisted of an on-center and an off-center cell sharing a common receptive field and both cells showed either transient or sustained responses to light stimulation. When a sinusoidally modulated light spot was presented at their receptive field center, the on-center and off-center cells responded half a cycle (approximately 180 degrees) out of phase with one another at all intensities tested. At a low temporal frequency (5 Hz), peak responses occurred in response to the maximum (in on-center cells) or minimum (in off-center cells) luminances of light modulation with an identical delay. The complementary phase property makes the cell couple work in a "push-pull" manner and enables transient cells, which show half-cycle rectification as they work alone, to transmit modulated light signals of complete cycle.
Forty-three single fibres were recorded from cat optic tract. They were tested with flashing lines of different lengths and/or spots of different dimensions. The area of centre excitation and of surround inhibition were represented in the length (or dimension)-response functions by the steep rising and falling phases, respectively. For most of the cells, a secondary gentle rise was seen when the stimulus extended beyond the inhibitory surround, indicating an extensive disinhibitory region (DIR) outside the classical receptive field (RF). Disinhibition appeared and developed concurrently with surround inhibition at stimulus intensities between 3 and 30 cd/m2, being represented in the phasic or the tonic component of responses depending on the cell type recorded.
This article reports the image analysis in the study of normal mucosa, polypoid adenoma, villus adenoma, atypical hyperplasia and tubular adenocarcinoma of the large intestine (15 cases each). The following 8 parameters: nuclear area (NA), plasma area (PA), ratio of nuclear to plasma area (RNPA), mean nuclear diameter, nuclear length, nuclear width, cell volume density and cell surface area density (SV) were observed and compared. Each value was tested by stepwise discriminational classification, giving an accuracy rate of 98%. These results suggested that analysis of variance in these groups was very significant in statistics (P less than 0.01). The mean values of RNPA and SV were especially significantly different between the adenocarcinoma group and the other groups (P less than 0.01). These results show that image analysis may be of importance in the histopathologic differentiation of precancerous from carcinomatous lesions.
The effects of cimetidine (Cim) on ventricular fibrillation threshold (VFT), diastolic excitation threshold (DET), effective refractory period (ERP), and vulnerable period (VP), were determined in both stable perfusion and postischemic reperfusion rat hearts. The results showed that reperfusion after 15 min global myocardial ischemia caused a significant decrease VFT and ERP, and an increase in VP and DET. Cim 1 mmol.L-1 prevented the lowering in VFT, shortening in ERP, and lengthening in VP from the postischemic reperfusion. Cim 0.1 mmol.L-1 attenuated the exacerbation of VFT and VP. Cim 0.01 mmol.L-1 did not exert any noticeable influence on the electrophysiological parameters. It was shown that Cim 1 mmol.L-1 protected myocardium against the aggravation of electrophysiological characteristics induced by postischemic reperfusion.
Contrast-study for goblet-cells of the intestinal mucosa, polypoid adenoma, villus adenoma, non-type epitheliosis and ductal adenoid carcinoma of colon was carried out via stereological analysis, including stereology measure of structure parameter and particle parameter of volume density(Vv), surface density(Sv) and number density(Nv). By means of coherent test system A100, spot count, intersection count and profile count method were applied in each group for goblet-cell counting. Data indicated that goblet-cell decreased corresponding to the lowering down of differentiation stage of epithelial cell in large intestine. Goblet-cell of nearly 50% of adenoid carcinoma disappeared completely. Indices of Vv less than 0.03, Sv less than 2.3mm-1, Nv less than 16.1mm-3 were considered as important criteria for the diagnosis of early carcinoma. Besides, non-type hyperplasia was obtained also in polypoid adenoma of colon. So, there is the possibility of undergoing malignant change.
This paper represented 500 patients with chronic osteomyelitis who were treated with Chinese medicinal herbs, Gan-ling Immersion Formula, in which focuses were soaked in combination with other therapies from 1986-1989. Healing rate was 83.2%. Effective rate was 98.0%. This therapeutic method was more effective for treating chronic osteomyelitis of the hand and the foot with shorter course. It was also good for treating refractory skin ulcer and scar, ilium osteomyelitis and sclerosing osteomyelitis. This method was immediately effective for acute attack of chronic osteomyelitis. Fistula in half of the patients could be closed within two therapeutic course. Most of the non-union and delayed-union of the bones could be unionized as chronic osteomyelitis was healed. Most dead bones could remove spontaneously, some could be absorbable, and seldom should be removed by operating on. These herbs are easy to get. The method was so simple and so safe that it could provide a new way of treating chronic osteomyelitis. Experiments showed Gan-ling Immersion Formula possessed relative strong anti-inflammation and external antibiotic effects.
Quantitative analysis of 10 cases of normal mucosa, 15 cases of villous adenoma and 20 cases of carcinoma of colon was studied by stereoscopic technique (Coherent Test System A 100). The results showed that there was statistical significance (P less than 0.01) in 6 parameters including Volume Density (Vv), Surface Density (Sv), Mean Diameter (D), Number Density (Nv) of nucleus and Mean Curvature Density (Kv) and Surface Curvature (K) of the gland, The new method of pathologic morphometry to differentiate adenoma from carcinoma was provided for clinical diagnosis. This method is more scientific, not only being different from the classical pathologic diagnosis, but also avoiding personal subjectivity. Colon adenoma was divided into two subtypes (A and B) according to the threshold of parameter. (Type A below the threshold and Type B above the threshold). Type A is well differentiated adenoma, but Type B tends towards malignancy. The higher the stereoscopic parameters, the higher the malignant tendency. Histologic parameters showed the objective index in pathologic diagnosis.
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