Middle Thoracic Regions Research Articles

Species Dependence of the Zero-Stress State of Aorta: Pig Versus Rat

The zero-stress state of an aorta can be characterized by the angle with which each segment of the vessel opens up when it is cut radially. The opening angle varies with the region of the aorta: significantly with respect to the axial location, less significantly with respect to polar angle of the radial cut. Both pig and rat aortas have large opening angles in the neighborhood of 130 deg in the aortic arch region. In the thoracic region, the species difference is evident. The opening angle of the pig aorta in the middle thoracic region is rather constant in the neighborhood of 60 deg. The opening angle of the rat aorta in the thoracic region varies considerably, decreasing to 10 deg at the lower end of the thoracic region. In the abdominal region the opening angle of the pig increases from 60 to about 80 deg, that of the rat increases from about 10 to 90 deg. The potassium ion has effect on vascular smooth muscle, but has little effect on the opening angle. This suggests that the opening angle is not sensitive to smooth muscle contraction, similar to a previously known result that the opening angle is not affected by papaverine. The vessel wall thickness and vessel diameter were measured. It is shown that the ratio of the wall thickness to diameter of the pig is considerably larger than that of the rat throughout the aorta.(ABSTRACT TRUNCATED AT 250 WORDS)

A CASE OF ESOPHAGEAL CANCER WITH HYPERCALCEMIA AND LEUKOCYTOSIS

A case of esophageal cancer with hypercalcemia and leukocytosis was reported. A 58-year-old man had an esophageal cancer, 3.6 cm in length, in middle thoracic (Im) region of the esophagus, a giant skip metastasis, 8 cm in diameter, in the gastric fundus, and multiple hepatic metastasis. Despite of bone metastasis and infection, serum calcium went up to 7.5 mEq/1 at maximum and leukocyte count rose to 3×104/ml.Serum PTH was rather lowered to 129 pg/ml. After total gastrectomy was carried out because of massive bleeding from the gastric lesion, serum calcium and leukocyte count decreased, and PTH increased. The production of CSF and PTHrP from the tumor was therefore suspected. Following the operation, radio-immuno-chemotherapy was carried out, but serum calcium re-elevated to 7.1 mEq/1 associated with growing of the hepatic metastasis.Though administration of cisplatin and elcitonin lowered the calcium level, the patient died of aspiration pneumonia on postoperative day 55. An autopsy did not disclose parathyroidal hypertrophy or bone metastasis. There were 13 cases of malignant tumor associated with hypercalcemia and leukocytosis for the past 5 years. Though most of them were squamous carcinomas, this case was only one report of esophageal cancer.

The physiological basis of transplantation of fetal catecholaminergic neurons in the transected spinal cord of the rat

1. 1. Fetal (E.17) rat locus coeruleus and mesencephalic dopaminergic neurons when implanted into the transected spinal cord of the young adult rat survive for periods of longer than four months. Axons of up to 15 mm in length are observed growing from the cell bodies of the implanted neurons. 2. 2. Fluorescent catecholaminergic (presumably dopaminergic) cell bodies are found in the caudal region of the transected, non-implanted spinal cord. 3. 3. After transection of the spinal cord at the middle thoracic region in rats, at different postnatal ages (PN. 0, 7, 14, 21 and 28), there is substantial recovery of motor coordination involving all four limbs in the PN. 0 and PN. 7 groups. Recovery is best in the PN. 7 group. There is almost no recovery in the PN. 28 group, and very little recovery in the PN. 14 and PN. 21 groups. 4. 4. Spinal locomotor generators in rat can, therefore, display a substantial degree of functional autonomy, if the spinal cord is cut before a certain critical stage of development (before PN. 14). These results have interesting implications with regard to current efforts to understand the mechanisms that regulate the spinal locomotor generators in experimental animals, and perhaps in man as well.

Complete gas myelography via lumbar injection under pressure.

Usually, myelography with complete gas-filling of the spinal subarachnoid space is performed via suboccipital puncture, with the technic recommended by Lindgren (8, 9). Odén (13), among others, has shown that gas myelography under these conditions is at least as accurate as myelography with iodized oils for the diagnosis of space-occupying lesions. Important features of the method are: (a) the contrast material, gas, is completely absorbed without residual adhesions and granulomas; (b) fluoroscopy is unnecessary; and (c) errors due to incomplete contrast-filling are avoided (10). Gas myelography by the Lindgren cisternal technic has gained only limited use, however, in spite of its good results and the innocuousness of gas as the contrast material. One reason for this may be reluctance to perform suboccipital puncture because of the associated risks. Further, suboccipital puncture is sometimes contraindicated or impossible because of skeletal anomalies or intraspinal lesions at the level of the foramen magnum. Lindgren recommended lumbar injection of gas if only the lumbar and lower thoracic regions were to be investigated and advocated injection up to a pressure of 500–600 mm H20 to achieve distention of the subarachnoid space (9). Lumbar injection of gas has also been used, however, to investigate the cervical region (1, 4, 14, 19). All the methods described have deficiencies, the most common of which is incomplete gas filling. It is known that the resorption of spinal fluid is augmented when the intrathecal pressure is increased (3, 11, 15). We have employed this increased resorption to achieve complete gas-filling up to the foramen magnum via lumbar injection in high pelvic position. No previous lumbar method seems to have regularly permitted this. Technic The spinal fluid is removed in two stages, first by tapping and later by increasing the pressure. Tapping Period: After lumbar puncture a jugular compression test is performed. If this is negative, as much spinal fluid as possible is tapped with the patient in either the sitting or the lateral decubitus position and with the head elevated 10–15°. Within ten to fifteen minutes, 50–80 ml are usually obtained. The fluid drips faster when the patient is in the sitting position, but he has more discomfort from headache and fall in blood pressure, and therefore we prefer the lateral decubitus position. When the drip from the needle begins to slow, the stopcock is closed and the patient is placed in the lateral decubitus position with the head lowered 15–20°. The needle is fitted with a two-way stopcock, permitting simultaneous registration of the pressure and the gas injection. The injection is made with a speed of about 5 ml per minute and continued until a pressure of about 550 mm H20 is reached. At this stage the gas-filling usually approaches the middle or upper thoracic region.

THE PATHOGENESIS OF IDIOPATHIC SCOLIOSIS

1. Scoliosis has four fundamental characteristic features as seen in the roentgenograms: Penetration or a transverse shift of the spine into the space surrounding it, contracture of the spine, rotation of the vertebrae, and compressions of the vertebrae on the concave side of the curve. 2. Penetration and compression are the essential scoliotic signs and are not encountered under physiological conditions. 3. The prevention of penetration is physiologically carried out by a passive mechanism. 4. The universal mechanical factor of all forms of acquired scoliosis is human gait, which in the presence of a definite pathological process brings about the deformity. 5. Rotation of the shoulders and of the trunk, or of the pelvis, is accompanied by rotation of the spine in the opposite direction. 6. The compression on the concave side is a primary characteristic of idiopathic scoliosis in the thoracic spine. 7. The vertebra is protected against undue compression by the disc, by the cartilaginous plate, and by the vertebral cortex which is composed of the end plates covering the upper and lower surfaces, of the circular bony hull, and of the epiphyseal ring. 8. The separation of the vertebral cortex from the intravertebral system, notably the separation of the epiphyseal ring and its partial displacement, represents the basic pathological process of idiopathic scoliosis in the thoracic spine. Separation is preceded by the infantile (juvenile) form of osteoporosis of the spine. 9. Postero-anterior roentgenograms reveal the presensce of channels crossing the vertebrae in a frontal direction. 10. The compressed vertebrae, as seen in the early stages, consist of two distinct portions: One is an ossified and porotic part, the core; the other, surrounding it or lying beside it, is a poorly or non-calcified, still more or less cartilaginous, portion. 11. In a typical case, idiopathic scoliosis of the thoracic spine starts in the cervicothoracic segment, and several years may pass before the middle and lower thoracic regions become involved. The process in the uppermost region presumably begins in the first four years of life. 12. Penetration and lateral movements, to the extent observed in scoliosis, are caused partly by subluxation in the articulations between the vertebrae. 13. Since idiopathic scoliosis of the lumbar spine is essentially of a rotatory nature without compression, a distinction is made between idiopathic scoliosis of the thoracic and lumbar spine. 14. Idiopathic scoliosis of the lumbar spine is made possible by congenital anomalies in the articular system of this region. The disappearance or decrease of the lumbar lordosis materially contributes to the development of the deformity. 15. Extrusion of the epiphyseal ring, if it occurs at all, is mostly a late phenomenon in the lumbar region. 16. The lumbar type of idiopathic scoliosis is characterized by rotation in the same direction of all vertebrae involved. The lumbar type is prognostically more favorable than the type involving the thoracic spine. 17. The prognostically most serious cases are those in which the congenital anomalies in the lumbar segment are combined with the pathological process encountered in the thoracic type of the deformity.