Changes in the subarachnoid space after experimental subarachnoid haemorrhage in the dog: Scanning electron microscopic observation

Summary The possible changes in the subarachnoid space after subarachnoid haemorrhage were studied in animals by using a scanning electron microscope (SEM).About 1 ml/kg of autogenous blood was injected intracisternally in 36 adult mongrel dogs to investigate changes in the subarachnoid space, over periods ranging from immediately after the injection to as long as 6 months.We have come to the conclusion that the injected blood disappears in about one to two weeks; the fibrosis or thickening of the arachnoid membrane appears in one to three weeks, and then returns to normal in a month in instances of rapid recovery, but there are some cases in which fibrosis persists for a long period and becomes chronic. The fact that an increase of fibrous tissue was found in the parietal region, where the injected blood had hardly reached, appears to indicate that the fibrosis is not always limited to the site of the haemorrhage but can occur in remote regions.We also discuss the usefulness of the SEM in the observation of the subarachnoid space, and the finding that vascular specimen preparations can be made by perfusing the brain with 2–10% phosphate-buffered formaldehyde solution.     

Prevention of subarachnoid fibrosis after subarachnoid haemorrhage with urokinase. Scanning electron microscopic study in the dog.

The author used the scanning electron microscope (SEM) to study the influence of urokinase on subarachnoid fibrosis after experimental subarachnoid haemorrhage (SAH). In the subchronic group of dogs, which were sacrificed three weeks after SAH, an average of 45--50 IU/kg of intrathecal urokinase diminished the fibrosis. In the chronic group, which was sacrificed three months after SAH, an average of 250 IU/kg of intrathecal urokinase also had considerable reducing effect. The author supposes that fibrinolytic therapy, with lysis of blood clot, contributes to clearance of the blood. We contrast this mechanism with the mechanism and effect of antifibrinolytic therapy. This experiment is the first successful attempt to influence subarachnoid fibrosis, and also the first experiment in which subarachnoid fibrosis could to some extent be prevented.     

Effect of experimental subarachnoid hemorrhage on CSF eicosanoids in the rat

A simple and inexpensive experimental model of subarachnoid hemorrhage (SAH) was developed in the rat. Based on accumulating data indicating the important role of arachidonic acid metabolites in the etiology of delayed cerebral vasospasm, we investigated changes induced by SAH on cerebrospinal fluid (CSF) levels of prostaglandin E2 (PGE2), F2 alpha (PGF2 alpha), and thromboxane B2 (TXB2). SAH was produced by the cisternal injection of blood via percutaneous suboccipital puncture. SAH rats (n = 200) were injected with 300 microliters of fresh autologous arterial blood; Control rats (n = 100) received the same volume of mock CSF. In 60 additional animals, no injections were made. To follow the changes induced by SAH on both the spectrum and time course of CSF eicosanoids, cisternal CSF samples were collected under basal conditions, 6, 12, and 36 after cisternal injection. PGE2, PGF2 alpha, and TXB2 were assayed in aliquots of CSF obtained by pooling samples from each experimental group. Eicosanoids were assayed using radioimmunoassay techniques. Arterial spasm was verified in parallel groups of SAH and control rats by comparison of the angiographic diameters of the basilar arteries (BA) and middle cerebral arteries (MCA) to that of the stapedial artery. CSF levels of all three eicosanoids were significantly higher in the SAH groups compared to both noninjected and mock-CSF injected control rats. These increases in concentrations of eicosanoids were accompanied by a decrease in the mean vascular diameter (77.5-82.0% of control) on day 2 following cisternal injection. We conclude that marked elevations of spasmogenic eicosanoids in the CSF are associated with experimental SAH.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunohistochemical and electron microscopic findings in a case of mixed hamartoma of the liver

A case of mixed hamartoma of the liver in a 36 day old female infant is reported herein. The resected tumor was well demarcated, measured 7.5 X 7.0 cm and weighed 179 gm. Microscopically, the tumor was composed of loose fibrous stroma intermingled with spindle and polygonal cells and ductular structures. The spindle and polygonal tumor cells displayed the distinct cytoplasmic staining for alpha-1-antitrypsin. Most of the tumor cells showed the characteristic ultrastructural features of immature hepatocytes, having numerous cytoplasmic microvillous structures, abundant rough and smooth endoplasmic reticulum and mitochondria. These findings suggest that embryonic liver cells, which are capable of transforming into biliary structures and hepatocytes, serve as essential elements of mixed hamartoma of the liver.     

Post-haemorrhagic subarachnoid fibrosis in dogs. Scanning electron microscopic observation and dye perfusion study

Summary Scanning electron microscopic observations of the subarachnoid space were made in dogs focussing upon the fibre components in both the normal subarachnoid space and in areas of post-haemorrhagic fibrosis. It was concluded that the fibrous tissue originates from the arachnoid membrane itself, while organized haematoma is considered to form a component of the fibrosis.Perfusion of the subarachnoid space of dogs with a solution of 0.1% Toluidine Blue was also done. This showed that cerebrospinal fluid (CSF) is carried from the subarachnoid space directly to the dural sinuses through a fine string-like structure, which is conceivably one of the collateral CSF absorptive pathways.     

Immunohistochemical and electron microscopic findings in a case of mixed hamartoma of the liver

A case of mixed hamartoma of the liver in a 36 day old female infant is reported herein. The resected tumor was well demarcated, measured 7.5×7.0 cm and weighed 179 gm. Microscopically, the tumor was composed of loose fibrous stroma intermingled with spindle and polygonal cells and ductular structures. The spindle and polygonal tumor cells displayed the distinct cytoplasmic staining for alpha-1-antitrypsin. Most of the tumor cells showed the characteristic ultrastructural features of immature hepatocytes, having numerous cytoplasmic microvillous structures, abundant rough and smooth endoplasmic reticulum and mitochondria. These findings suggest that embryonic liver cells, which are capable of transforming into biliary structures and hepatocytes, serve as essential elements of mixed hamartoma of the liver. This case was presented at the 181st KBK in Saga, Japan     

Scanning electron microscopic observations of the vascular structure of vertebral end-plates in rabbits

We used scanning electron microscopy to examine the microcirculation in the vertebral end-plates of rabbits. The arteriola arborizes and swells at the end-plate and then coils to make a microvessel loop. This loop is the structure we refer to as a vascular bud. We suggest that these loop structures of the capillaries play a major role in the nutrition of the intervertebral discs.     

Correlation between CT findings and subsequent development of cerebral infarction due to vasospasm in subarachnoid haemorrhage

Summary We have studied the correlations between computed tomograms (CT), clinical severity at the time of onset, and subsequent development of cerebral infarction due to vasospasm in 32 cases with subarachnoid haemorrhage secondary to rupture of cerebral aneurysms. It was found that the clinical severity could be judged by CT as shown by the amount of blood in subarachnoid space. Furthermore, it was possible to predict the subsequent occurrence of cerebral infarction by sequential findings of CT. A Hounsfield number of the high density area over 60 showed good correlation with the development of cerebral infarction.     

Scanning electron microscopic findings of the gliding surface of the A1 pulley in trigger fingers and thumbs

The gliding surface of the A1 pulley was studied in 20 cases of primary trigger finger by scanning and transmission electron microscope. In 12 normal specimens, the whole deep surface was covered uniformly by an amorphous extracellular matrix. In the pathological samples, there was the same general surface appearance but, also, areas, varying in shape and dimension where loss of the extracellular matrix had exposed the collagen fibres and a few cells of the middle layer of the pulley. There were also changes typical of "chondroid-metaplasia". These data were confirmed by transmission electron microscopy. The fragmented areas are probably the result of altered forces of friction between the pulley and the flexor tendon and may be the "gate" through which the forces of friction cause chondroid-metaplasia in the underlying fibrous tissue, a phenomenon recognised to be one step in the pathogenesis of trigger finger.     

Health care disparity in the care of the vascular patient

Peripheral vascular care continues to mature into a well-developed multidisciplinary subspecialty. Continued growth as a collaborative subspecialty will require delivering the highest quality medical care to all Americans. US census projections predict that greater than one half of all American citizens will identify themselves as ethnic or racial minorities by 2050. Evolving research has established significant health care disparity, or preventable differences in disease incidence and vascular procedure outcomes associated with socioeconomic, gender, language, geographic, racial, and ethnic variables. As a necessary step in the evolution of vascular care, practitioners, societies, and vascular departments should begin to adopt proven practices that enhance our ability to deliver equal care to an increasingly diverse American population.     

Falcine venous plexus within the falx cerebri: anatomical and scanning electron microscopic findings and clinical significance

Background

Only limited attention has been paid to the anatomy and clinical importance of the falcine venous plexus. The aim of this study was to evaluate the falcine venous plexus anatomically using scanning electron microscopy (SEM), and to provide guidance for neurosurgical approaches.

Methods

Latex or ink was injected into the superior and inferior sagittal sinus. The falcine venous plexus lying within the connective tissue of the falx cerebri was observed by dividing the falx into thirds (anterior, middle and posterior). Further, the SEM appearance of the falcine venous plexus was evaluated.

Results

The anterior third of the falx cerebri consisted of small diameter falcine venous vessels. These vessels were localized close to either the superior or inferior sagittal sinus, and none extended as far as mid-falx cerebri levels in any of the 16 cases. They communicated with either superior or inferior sagittal sinuses, but not with both of these sinuses. In the middle third of the falx cerebri, the majority of the vessels of the falcine venous plexus had larger diameter compared to those of the anterior third. These vessels extended the length of the falx cerebri levels. They communicated with both superior and inferior sagittal sinuses. In the posterior third of the falx cerebri, the vessels of the falcine venous plexuses had the largest diameter and were located at the junction of the inferior sagittal sinus and the straight sinus. They were localized at the lower two-thirds of the falx cerebri. In all cases, the dense venous networks communicated with the inferior sagittal sinus but not with the superior sagittal sinus. The falcine venous plexus observed in the posterior third of the falx cerebri was denser than in the anterior and middle portions. The SEM revealed small vessels whose diameter ranged between 42 and 138 μm. The vessels of the falcine venous plexus in the anterior third had a mean diameter of 0.42?±?0.1 mm, in the middle third a mean diameter of 0.87?±?0.17 mm, and in the posterior third, 1.38?±?0.21 mm.

Conclusion

The falcine venous plexus is a network of venous channels that exists within the connective tissue of the falx; the sizes and patterns of communication of these structures showed regional differences. Neurosurgeons should be aware of the regional differences when making an incision or puncturing the falx during a surgical approach.     

Scanning electron microscopy of the subarachnoid macrophages after subarachnoid haemorrhage,and their possible role in the formation of subarachnoid fibrosis

Summary Sixty dogs with experimental subarachnoid haemorrhage (SAH), repeated SAH, and subarachnoid fibrosis (examined three weeks and three months after SAH, and treated with urokinase or dexamethasone) were examined by scanning electron microscope (SEM). The authors observed the resting and activated macrophages, the erythrophagocytosis, and giant cells in the subarachnoid space after SAH. They consider that the macrophages play an important role in the formation of subarachnoid fibrosis, similar to the role of macrophages in fibrosis in other sites.This work was supported by the Japan Society for the Promotion of Science.     

High-voltage electrical injury: electron microscopic findings of injured vessel, nerve, and muscle

Bilateral legs damaged by high-voltage electrical injury were treated by amputation and a free thin rectus abdominis myocutaneous flap with reduced muscle. Damaged arteries at 2 months after injury showed disappearance of endothelium, and a decreased number and morphological changes in smooth-muscle cells. Injured nerves and muscles showed early regenerating processes after total degeneration, and no progressive muscular necrosis. These results suggest that severe degeneration of the neurovascular bundle and muscle is unavoidable in high-voltage electrical injuries of the extremities. Therefore, early amputation, sequential debridement, late coverage by a flap, and prolonged rehabilitation are required in this injury.     

Relationship between a traumatic life event and an alteration in stress response

An Erratum has been published for this article in Stress and Health 20(5) 2004, 309. The relationship between past traumatic experience and stress tolerance is poorly understood. To investigate the relationship among past exposure to trauma, stress tolerance and other mental health indexes, experience of traumatic events, depression, anxiety, and job strain were assessed in 2959 male and 279 female workers. Job strain was used as an indicator of stress tolerance in this study. Past traumatic experience was shown to increase later anxiety for both sexes, and increase depression and job strain in male subjects. For the first time, people with past traumatic experiences were found to feel a stressor's influence more strongly. Further, those influences differed according to the type of past trauma. The existence of interactions among the experience of traumatic events, depression/anxiety, and strain indicated that stress tolerance seemed to be an important element in the trauma response mechanism. Copyright © 2004 John Wiley & Sons, Ltd.