Fresh subcutaneous tissue from the rabbit's ear was processed with copper ferrocyanide method (Karnovsky and Roots, 1964) for demonstrating acetylcholinesterase. The arterio-venous anastomoses were revealed by the abundant "cholinergic" nerve fibers present around its arterial and intermediate segments. These nerves formed a dense network around these segments of AVA which gives AVA a conspicuous and outstanding picture under the microscope. 262 AVA were identified and their length and outer diameter of the intermediate segment were measured. The longest was 620.6 ?m, the shortest 81.9 ?m, and the averaging length was 254.8 ?m. Their outer diameters fell between 109.2～20?m, with an average of 52.2 ?m. The authors condered the measurements of the intermediate segment of the AVA give more significant information than the total length of the AVA.The AVA were classified into the following types according their morphological characteristics: the simple type (including the long and thin type, and short and thick type) and the complex type (including bifurcate, trifurcate, quarifurcate, compound, and circular types). This method of demonstrating AVA morphology was compared with former observations made directly in vivo or by histological methods and it serves as an new tool for the investigation of AVA.

By means of the fluorescent histochemistry the small intense fluorescent (SIF) cells of the rat heart were identified under the fluorescent microscope, then the tissue containing these cells were prapared for electron microscopy. Ultrastracturally SIF cells were small in size and contained a lot of granules which can be distinguished into two types of electric density, and abundant number of mitocondria which appeared about 20 in each section of SIF cell at the nuclear level, and a large Golgi complex which consisted of 4-7 cisternae arranging in paralled array and some vesicles. Many single cisternae of rough endoplasmic reticulum were distributed in their cytoplasm. Adhesion zones and interdigitated processes were often observed between two SIF cells. Cholinergic nerves formed afferent synapses with SIF cells. SIF cells often occured near fenetrated capillaries. We found that the core of the granulated vesicles of some SIF cells were released into the perivascular space. These results indicated that SIF cells of the rat heart may have a local regulatory fnuction either as endocrinal or paracrinal cells.

The distribution of atriopeptins in the rat's heart was studied with immunohis-tochemical method. It was noticed that the immuno-reactive granules existed in most atriaI muscle cells. It was abundant in the cytoplasm about the paranuclear position. The cardiocytes of both atrial appendages gave an intense immuno-reaetion. Most cardiocytes of right atrium were more reactive than those of left atrium. Parts of atrial muscle cells which were distributed in the back of the left atrium, atrial septum and coronary sinus were negative in reaction.

In this paper the distribution of the atriopeptin-like immunoreactive substance in the ventricles of rat embryos of 13-19 days old was investigated by immunohistochemistry and electron microscopy. The results showed that atriopeptin-like immunoreactive granules were located around the nucleus in some cardiocytes of the ventricles of rat embryos. Most of these cells were distributed in the pectinated or trabecular structures in the luminal surface of left ventricle and a few of them in the myocardium of left and right ventricles. In the same embryo ventricle muscle cells contained less immunoreactive granules than those in the atria. Under electron microscope the atrial specific granule-like granules were found mainly near the Golgi complex. Some cells were devoid of such granules in cytoplasm. In the ventricles the distribution of the muscle cells containing atrial specific granule-like granules corresponds to the sites of muscle cells containing atriopeptin-like substance from the immunohistochemical study. The results suggest that the so-called "atriopeptin" is also present in some ventricular myocytes in rat embryos. The presence of atriopeptin-like substance may be related to the unique type of embryonic circulation.

The occurrence and distribution of the atrial muscle cells containing atriopeptinimmunoreactive granules were studied in rat embryos and newborn rats with immunohistochemistry. The results showed that immunoreactive granules occurred in a few atrial muscle cells of embryos at 13 days old but they were not found in those cells at 11 and 12 days. With development of the embryos, the number of cells containing immunoreactive granules in atrium increased and their granules became more abundant and located mainly around the nucleus. Most of the granulated atrial muscle cells distributed in trabecular structure of the luminal surface of atria. They gradually decreased in number towards the pericardial side. The nongranulated atrial muscle cells mainly located near the pericardium and in atrial septum. The results suggested that the specific differentiation of atrial muscle cells occurred at early period of rat embryos, some cells became atriopeptin immunoreactive positive cells, while the others remained as negative cells. The feature of the differentiation of atrial muscle cells may reflect the functional development of the atria.

Eighty adult male Wistar rats were randomly divided into three groups: 1. In the experimental peptic ulcer group, 35 animals were induced to develop peptic ulcer by injecting 0.05 ml/kg of glacial acetic acid (more than 99%) into the submucosa of the stomach after laparotomy under aseptic conditions. 2.In the saline control group, 35 animals were injected with 0.05 ml/kg of saline into the submucosa of the stomach after laparotomy. 3.In the normal control group, 10 normal animals without any treatment were raised under the same condition as group 1 and group 2. The thyroid glands of three groups were taken at definite time intervals (1-28 days) after the operation. The right thyroids were prepared for cryostat sections after hexane quenching (-60℃) and subjected to the histochemical studies of acid phosphatase (AcP), alkaline phosphatase(AIP), a-glycerophosphate dehydrogenase (a-GPD), succinate dehydrogenase (SDH), glucose-6-phosphate dehydrogenase (G6PD), and nonspecific esterase (NsE). The left thyroids were fixed in Carnoy's fluid, stained with HE and subjected to histological study. The reactions of enzymes of the follicular cells in the group 2 were weaker than those in the group 3 (normal control) during the period of 2-21 days after the operation. The follicular cells became flattened and follicular lumens increased in size. These changes recovered to normal on the 28th day after the operation. In the follicular cells of group 1. In which peptic ulcer developed after injection of glacial acetic acid, the reaction of A1P was weaker than those in the group 3, but stronger than those in the group 2. The reations of a-GPD, SDH, and G6PD were stronger than those in the group 2, and as well as those in group 3. The reaction of AcP was stronger than those in the group 2 and group 3 during the 6-21 days after the operation. The follicular cells in the group 1 became flattened and the follicular lumens increased in size only during the period of 4-10 days after the operation and recovered on the 14th day after the operation. These findings suggested that the thyroid follicular cells of rat involved in the metabolic activities of the repair of gastric ulcer.

The histological and histochemical changes in the C cells of the rabbit thyroid during experimental peptic ulcer were studied. Acetylcholinesterase was used as the marker enzyme to identify C cells. Forty-nine adult male rabbits were randomly divided into three groups: 1. In the experimental peptic ulcer group, 24 animals were induced to develop peptic ulcer by injecting 0.15 ml/kg of 40% acetic acid into the submucosa of the stomach after laparotomy under aseptic conditions. 2. In the saline control group, 18 animals were injected with 0.15ml/kg of normal saline into the submucosa of the stomach after laparotomy. 3. In the normal control group, 7 rabbits were raised under the same conditions as groups 1 and 2 without any treatment. Thyroid glands were removed at different time intervals (1-28 days) after the operation. The right thyroids were prepared for cryostat sections and subjected to enzyme histochemical studies. The left thyroids were fixed in Carnoy's fluid and subjected to histological and other histochemical studies. The findings were as follows.In the C cells from the normal control group, the reactions of acetylcholinesterase, nonspecific esterase and acid phosphatase were rather strong. Acetylcholinesterase can be taken as a specific marker enzyme for C cells. The reactions of thiamine pyrophosphatase, succinate dehydrogenase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase and ribonucleic acid were weak which suggested that normal C cells were a at a lower state of functional activity. In the saline control group, the histochemical changes showed that the C ceils were in an active functional state during the early period of the experiment, which may possibly reflect the response of C cells to the operation stress and wound healing. In the experimental peptic ulcer group, the reactions of acetycholinesterase, nonspecific esterase, acid phosphatase, succinate dehydrogenase, glucose-6-phosphate dehydrogenase, thiamine pyrophosphatase and ribonuclic acid of the C cells in the experimental peptic ulcer group were stronger than those of the saline control group 7-28 days after the operation. These histochemical changes of C cells duting this period may suggest that the C cells were active in function and perhaps participated in the regulatory activities of the organism during its recovery from the disease. In none of the three groups did the C cells show any conspicuous histological and morphological changes at any time in the experiment.

Serial cryostat sections of five hearts and seven atria of rats were prepared. Falck's fluorescent histochemical method, and histological staining methods wereutilized in succession on the same section. Small intensely fluorescent cells in rat's heart are round, oval or polyhedral in shape. A few of them possess processes. These cells are found in the heart in four major forms: dense spheroid groups, loosely associated clusters, linear alignment, and isolated cells.The number of small intensely fluorescent cell varies between 442-664 cells in the adult rat's heart. 86-92% of them are localized in subepicardium of atrium, especially several areas on the dorsum of atrium. No small intensely fluorescent cell was found in endocardium. The rest of these cells are scattered in other parts of the heart. The distribution areas of atrial nerve ganglia and small intensely fluorescent cells in subepicardium are similar. There are no such cells in some atrial ganglia and there is no relation between the number of these cells in the ganglion and its size. Parts of these cells are often found near the blood vessels. Small intensely fluorescent cells are not morphologically associated with the conduction system in the rat.

Using a quantitative method, the healing of the experimental gastric ulcer in rats was studied in various states of thyroid function. Rats were made hypothyroid by ingestion of thiouracil (0.1％ solution in drinking water for 10 days). Rats were made slightly hyperthyroid by ingestion of thiouracil and simultaneous administration of T_4 (3?g/100 g/day,ip) for 10 days. Rats were made hyperthyroid by administration of excess T_4 (10?g/100 g/day, ip) for 10 days. The normal rats served as controls. In all of these rats, gastric ulcer was induced by injecting a small quantity of glacial acetic acid into the submucosa of the stomach after laparotomy under aseptic conditions. After operation the rats in four groups were given those drugs as above respectively for 10 days. The volume (7.71?0.52mm~3' 5.5?0.78 mm~3 for control) and area (8.29?0.90mm~2; 4.39?0.73mm~2 for control) of gastric ulcer increased in the rats with hypothyroidism. The healing rate of gastric ulcer retarded (-30?9.4％ for volume healing rate, -50?2.1％ for area healing rate). The volume (4.75?0.88mm~3) and area (4.05?0.93mm~2) of gastric ulcer decreased in the rats with slight hyperthyroidism, and the healing rate of gastric ulcer accelerated (37?3.8％ for volume healing rate, 49?3.2％ for area healing rate). The volume (4.88?0.90mm~3) and area (6.16?0.74mm~2) and the healing rates of gastric ulcer in the rats with hyperthyroidism were similar as those of control. These findings suggested that (1) thyroxine is necessary for healing of the experimental gastric ulcer in rats and (2) thyroxine seem to accelerate healing of the experimental gastric ulcer in rats.

Stereological methods were applied in the qantitative ultrastructural analysis of the chromaffin cells in adrenal medulla of normal adult guinea pigs.The main result includes:(1)The average volume(V)of each cell(714?m~3)and its nucleus (167?m~3);(2)volume density(Vv)of mitochondria(0.082?m~3/?m~3),lysosomes (0.0045?m~3/?m~3),rough-endoplasmic reticulium(0.013?m~3/?m~3),smooth-endopas- mic reticulium including Golgi apparatus(0.024?m~3/?m~3)and granule vesicles (0.23?m~3/?m~3);(3)surface density(Sv)of cell membrane(0.87/?m~2/?m~3)and mitochondrial outer membrane(0.90?m~2/?m~3);(4)numerical density(Nv)of mitochondria(0.89/?m~3),lysosomes(0.11/?m~3)and granule vesicles(59.98/?m~3); (5)the mean diameter of granule vesicles(144 nm),In addition,several small- granule chromaffin cells were quantified separately from the general chromaffin cells.They contain granule vesicles with an average diameter of 97 nm and show a significant difference in surface density of cell membrane(1.54?m~2/?m~3)from that relevant value of general chromaffin cells(P