Anatomical aspects of the arteria inferior posterior cerebelli for posterior fossa surgery]

As the arteria inferior posterior cerebelli sometimes causes surprises of grave consequence at surgical approaches, its origin and course had to be described in detail. For this aim, we especially considered the local relationships of this artery with the medulla oblongata and the cranial nerves of the posterior fossa. Branches of the a. inferior posterior cerebelli supplying the medulla oblongata have been noticed in relation to the arterial supply of the medulla oblongata by corresponding vessels and the aa. spinales lateralis and posterior with special reference to all the possible collateralizations.     

Electron-microscopic immunocytochemistry of 5-hydroxytryptamine in the ascidian endostyle

Summary Corticotropin releasing factor (CRF)-immunoreactive (IR) perikarya, visualized by the indirect immunoperoxidase method in colchicine-pretreated cats, were localized in many discrete regions of the medulla oblongata. They were found mainly in the dorsal aspect and midline of the medulla oblongata, and more rostrally in the ventrolateral portion. Our results also demonstrated CRF-IR neurons in the rostrocaudal extent of the inferior olive, probably projecting to the cerebellar cortex via thick axons visualized along the lateral edge of the medulla. CRF-IR olivary cells were also found in the pontine cat from which the forebrain was removed, but neither in hypophysectomized nor adrenalectomized cats.     

Anterior spinal arteries. Origin and distribution in man

This study was designed to extend our present knowledge of the origin and distribution of anterior spinal arteries and was carried our using 31 human cadavers with arterial injections of natural latex. The conclusions reached are that there are always one or two anterior spinal arteries (right or left), which proceed from the intracranial segment of the vertebral arteries. These arteries have a descending course, with distribution into the ventral face of the medulla oblongata and the first cervical segments of the medulla spinalis. In cases where there are two anterior spinal arteries, they anastomose with each other to form the common, unpaired and median anterior spinal artery. The different observed locations of the origins of anterior spinal arteries may be systematised into three types. Each of these types has differential characteristics: bilateral origin (type I; 77.4%), unilateral origin (type II; 9.7%) and origin in an intervertebral transversal anastomosis (type III; 12.9%). We do however subdivide the bilateral origin group, according to the calibre of the arteries, into the subtypes 'balanced' (type Ia; 22.6%), 'right dominated' (type Ib; 32.2%) and 'left dominated' (type Ic; 22.6%). The collaterals of the anterior spinal arteries which distribute into the ventral face of the medulla oblongata are described.     

Novel Classification of the Posterior Auricular Artery Based on Angiographical Appearance

Purpose

To investigate the length variation of the posterior auricular artery and propose a novel classification of the posterior auricular artery based on angiographical appearance.

Patients and Methods

A series of 234 consecutive patients who had undergone conventional cerebral angiography was analyzed. The posterior auricular artery was examined on the lateral projection of the external carotid or common carotid arteriography. The posterior auricular artery was classified into four groups by length, using the external auditory canal and the top of the helix as radiographical landmarks. Our proposed classification is as follows: Type A, posterior auricular artery terminates between its origin and the center of the external auditory canal; Type B, posterior auricular artery terminates between the center of the external auditory canal and the top of the helix; Type C, posterior auricular artery terminates between the top of the helix and the vertex; and Type D, posterior auricular artery reaches up to the vertex.

Results

A total of 424 (right, 214; left, 210) posterior auricular arteries were analyzed in 111 men and 123 women aged 11 to 91 years (mean, 61.0 years) examined for aneurysms in 78 cases, occlusive vascular diseases in 56, intracranial hemorrhages in 41, tumors in 35, and others in 24. Types A, B, C, and D were found in 15.1%, 34.9%, 48.8%, and 1.2% of the patients, respectively.

Conclusion

A novel classification of the posterior auricular artery identifies four types based on its length on cerebral angiography.     

INCORPORATION OF 14C FROM [U-14C]GLUCOSE INTO FREE AMINO ACIDS IN MOUSE BRAIN REGIONS UNDER CYANIDE INTOXICATION

—During anoxia induced by the administration of potassium cyanide, [U-¹⁴C]glucose was injected intraperitoneally into adult mice and they were decapitated at 5, 15 and 30 min after the injection. After freeze-drying in vacuo, differences in the uptake of radioactive carbon from [U-¹⁴C]glucose into free amino acids (glutamate + glutamine, aspartate + asparagine, GABA, alanine and glycine) in mouse cerebral neocortex, cerebellar hemisphere, caudate nucleus, thalamus, hypothalamus and medulla oblongata were investigated (by macroautoradiography and GLC separation) and compared with those obtained under normal conditions. (1) During anoxia, autoradiographical densities in the thalamus and medulla oblongata were higher than that in the cerebral neocortex and caudate nucleus. (2) Among specific radioactivities (d.p.m./μmol) of free amino acids, alanine gave the highest value during anoxia, except in the cerebellar hemisphere and hypothalamus at 5 min and the medulla oblongata at 30 min. (3) During anoxia, the specific radioactivities of alanine and glycine in each brain region did not significantly decrease at 15 and 30 min compared with those under normal conditions. During anoxia, the specific radioactivity of glutamate + glutamine in the cerebellar hemisphere and hypothalamus did not significantly decrease compared with the normal conditions, while that of GABA, aspartate + asparagine and glutamate + glutamine in the cerebral neocortex, caudate nucleus, thalamus and medulla oblongata showed an increase. (4) The percentage decrease of glutamate + glutamine and aspartate + asparagine at 5 and 15 min was highly significant in the cerebral neocortex and caudate nucleus.     

Various forms of the celiac trunk and its anastomoses with the superior mesenteric artery]

Three rare varieties of upper abdominal arteries were compared with similar cases in the anatomical literature. An attempt was made to obtain a classification of the supernumerary branches of the celiac trunk and of the anastomoses between the celiac trunk and the superior mesenteric artery. One or more supernumerary branches of the celiac artery can be observed: (1) the superior mesenteric artery; (2) an accessory hepatic artery; (3) a posterior pancreatic artery; (4) a colic artery; (5) an accessory splenic artery; (6) a connecting branch to the superior mesenteric artery, and (7) an inferior phrenic artery. The following types of anastomoses between the celiac artery and the superior mesenteric artery can be distinguished: (1) direct connection; (2) anastomoses within the hepatic artery; (3) anatomoses following pre- or postnatal stenosis, and (4) the pancreatic arcades. For the first type the theory of TANDLER (longitudinal anastomosis) is abandoned. The development of the second type is as yet unresolved. In the case of the last two types a postembryonal formation is possible.     

Immunohistochemical mapping of adrenomedullin in the human medulla oblongata

We studied by immunocytochemistry the expression of adrenomedullin (AM) in the human medulla oblongata, sampled from 13 adult subjects (mean age: 38 years), whose medical history was negative for neurological and neurovascular pathologies. Immunoreactive neurons were found in the medulla oblongata with statistically significant differences among the various nuclei (one-way ANOVA, P < 0.001). The hypoglossal nucleus showed higher AM expression than that of the spinal tract of the trigeminal nerve (P < 0.05), solitary tract nucleus (P < 0.05), nucleus intercalatus (P < 0.05), and area postrema (P < 0.05). The arcuate nucleus and inferior olivary nuclear complex showed lower AM expression than the hypoglossal nucleus (P < 0.001), vestibular nuclei (P < 0.01), cuneate and gracile nuclei (P < 0.05), lateral column of the reticular formation (P < 0.05), and nucleus ambiguous (P < 0.05). Furthermore the nuclei were grouped with reference to their function, into somatic sensitive nuclei, somatic motor nuclei, visceral nuclei, reticular formation, and nuclei involved in cerebellar functions. The ANOVA revealed statistically significant differences (P < 0.001) in mean AM scores among the different groups. Nuclei involved in cerebellar function showed the lowest mean AM score (P < 0.05). The difference in AM score between somatic motor nuclei and visceral nuclei was also statistically significant (P < 0.05). Widespread AM immunoreactivity in the nuclei of the medulla oblongata may account for the role of the peptide in neuronal function and regulation of regional blood flow. Differences in the expression of AM in the nuclei studied indicate the different involvement of AM in neurotransmission and neuromodulation.     

心外膜应用腺苷时c—fos在脊髓延髓和丘脑中的表达

在１２只切断两侧缓冲神经和迷走神经的麻醉大鼠,观察了心外膜应用腺苷对脊髓,延髓和丘脑ｃ－ｆｏｓ原部基因表达的影响。结果显示：心外膜应用腺苷组大鼠,动脉血压和心率无明显变化;脊髓Ｔ３节段背角,延髓巨细胞旁外侧核以及丘脑的腹后外侧核,后核,中央外侧核和束旁核等部位Ｆｏｓ蛋白样免疫阳性反应神经元显著增加;而在溶剂对照组大鼠,仅见少数ＦＬＩ细胞。     

Development of serotonergic neurons of dorsal raphe nuclei in mice with knockout of monoamine oxidase a and 5-HT1A and 5-HT1B autoreceptor

The morphological changes in the development of serotonergic neurons of the dorsal raphe nuclei in the medulla oblongata was studied by immunocytochemistry in mice with knockout of 1A and 1B serotonin autoreceptors as well as monoamine oxidase A. Serotonin autoreceptors regulate electric activity of serotonergic neurons as well as the synthesis and release of the neurotransmitter, while monoamine oxidase A catalyzes its degradation. These genetic modifications proved to have no effect on the number of serotonergic neurons in the medulla oblongata but induced morphofunctional changes. Decreased cell size and increased intracellular serotonin level were observed in the case of monoamine oxidase A deficiency, while excessive cell size and decreased intracellular serotonin level were observed in the case of autoreceptor deficiency. The data obtained confirm the hypothesis of autoregulation of serotonergic neurons in development.     

THE EFFECT OF PHYSOSTIGMINE AND NEOSTIGMINE ON THE CONCENTRATION OF GLYCOGEN IN VARIOUS BRAIN STRUCTURES OF THE RAT

Abstract—

• 1 Hypothalamus, mesencephalon, cerebral cortex, cerebellar cortex and medulla oblongata of the rat brain contain varying amounts of glycogen. The highest concentration was found in the medulla, and the lowest in the hypothalamus.
• 2 Low doses of physostigmine produced a significant decrease in the concentration of glycogen in mesencephalon, cerebral cortex, cerebellar cortex and medulla. Higher doses of physostigmine were necessary to produce glycogenolysis in the hypothalamus. In the first four structures glycogen stores were almost equally sensitive to the action of physostigmine. Neostigmine did not affect brain glycogen. The glycogenolytic effect of physostigmine was dose-dependent.
• 3 Both atropine and propranolol were found to block the glycogenolytic effect of physostigmine in brain.
• 4 It is concluded that probably both cholinergic and adrenergic processes participate in the glycogenolytic effect of physostigmine. It is suggested that physostigmine initiates the cholinergic processes which then trigger adrenergic processes.

     

Cytochemical localization of alkaline phosphatase in the ependyma of the rat medulla oblongata

Summary The ependyma of the IVth ventricle and the central canal of the rat medulla oblongata was investigated using the cytochemical technique for alkaline phosphatase (AlPase) which revealed two types of ependymal cells in the medulla. The central canal type of the ependymal cell occupying the dorsal part of the central canal in the lower medulla exhibited intense AlPase activity with light microscopy. These cells had reaction products in all plasma membranes, including the microvilli and the cilia at the luminal cell surface. Some cells appeared to be tanycytes, since the process reached the basement membrane of the parenchymal blood vessel. The ventricular type of ependymal cells, which form the floor of the IVth ventricle and the central canal, contained no reaction products in any structure of the luminal cell surface.The possible relationship between the cerebrospinal fluid and the nervous tissues through the ependymal linings is discussed.     

脑干缺血对听觉脑干反应影响的实验研究

目的 :探讨脑干缺血模型ABR变化特点及其在脑缺血早期诊断中的应用价值。方法 :阻断猫基底动脉不同部位血流 ,观察记录阻断血流后不同时间ABR变化特点及其规律。结果 :①夹闭基底动脉上、下段或小脑下前动脉 10min左右 ,ABRP3 ,P4振幅明显减小 (P <0 .0 1,P <0 .0 5 ) ,60min恢复夹前水平 ;②夹闭基底动脉上段 10～60minP5明显减小 (P <0 .0 5 ) ,直到 12 0min尚未恢复至夹前状态。结论 :①猫的ABRP3脑区的血供主要来自小脑下前动脉 ,P1,P2产生部位基本不依赖基底动脉供血 ;②轻度暂短性脑缺血时ABR振幅比潜伏期更敏感 ,振幅减小的程度与脑干缺血的程度密切相关 ;③ABR可用于脑缺血定位诊断及脑功能动态观察的电生理检测。     

Influence of Proline on Rat Brain Activities of Alanine Aminotransferase,Aspartate Aminotransferase and Acid Phosphatase

Hyperprolinemia type II (HPII) is an autosomal recessive disorder caused by the severe deficiency of enzyme ¹-pyrroline-5-carboxylic acid dehydrogenase leading to tissue accumulation of proline. Chronic administration of Pro led to significant reduction of cytosolic ALT activity of olfactory lobes (50.57%), cerebrum (40%) and medulla oblongata (13.71%) only. Whereas mitochondrial ALT activity was reduced significantly in, all brain regions such as olfactory lobes (73.23%), cerebrum (70.26%), cerebellum (65.39%) and medulla oblongata (65.18%). The effect of chronic Pro administration on cytosolic AST activity was also determined. The cytosolic AST activity from olfactory lobes, cerebrum and medulla oblongata reduced by 75.71, 67.53 and 76.13%, respectively while cytosolic AST activity from cerebellum increased by 28.05%. The mitochondrial AST activity lowered in olfactory lobes (by 72.45%), cerebrum (by 78%), cerebellum (by 49.56%) and medulla oblongata (by 69.30%). In vitro studies also showed increase in brain tissue proline and decrease in glutamate levels. In vitro studies indicated that proline has direct inhibitory effect on these enzymes and glutamate levels in brain tissue showed positive correlation with AST and ALT activities. Acid phosphatase (ACP) activity reduced significantly in olfactory lobes (40.33%) and cerebrum (20.82%) whereas it elevated in cerebellum (97.32%) and medulla oblongata (76.33%). The histological studies showed degenerative changes in brain. Following proline treatment, the animals became sluggish and showed low responses to tail pricks and lifting by tails and showed impaired balancing. These observations indicate influence of proline on AST, ALT and ACP activities of different brain regions leading to lesser synthesis of glutamate thereby causing neurological dysfunctions.     

Several morphologic changes in the blood vessels of the rabbit medulla oblongata arising under the influence successive exposure to gravitational overloading and hypokinesia]

Morphological changes in blood vessels of the rabbit medulla oblongata were studied after successive effects of maximum-bearing gravitational overloadings of 10 units applied at different directions and hypokinesia of various duration. Blood system of 35 rabbits was injected with Gerota's mass, cleared horizontal sections of the medulla oblongata 120 mkm thick were stained with hematoxylin--eosin and after Van Gieson. The experiments demonstrated various, quantitative and qualitative, changes in the vessel structure of the medulla oblongata, prevalence of one of the factors applied--in one combination and successive application; total resulting effect of overloading and hypokinesia--in the other combination; peculiar morphological changes unusual to any of the two factors--in the third combination. It was also demonstrated that readaptation for 12 weeks resulted in a significant restoration of the blood vessel structure in the rabbit brains preliminarily subjected to a successive effect of hypokinesia for 4 weeks and overloading in cranio-caudal directions.     

Neurochemical correlates of alloxan diabetes: brain aminotransferase heterogeneity in the rat.

The activity levels of Aspartate aminotransferase (AAT) and Alanine aminotransferase (A1AT) in the cerebrum, Cerebellum, optic lobes and medulla oblongata of normal and alloxan-diabetic rats were determined. The Heterogeneity of aminotransferases in the cerebral and cerebellar regions of normal and alloxan-diabetic rats was studied via agar gel electrophoresis. In general, the activities of the two aminotransferases increased in the brain of alloxan-diabetic rats. Cerebral and cerebellar distribution, sub-unit pattern and relative electrophoretic mobility of the isozymes of AAT and A1AT of normal and diabetic rats are described.     

HISTOCHEMICAL MAPPING OF LACTATE DEHYDROGENASE AND MONOAMINE OXIDASE IN THEMEDULLA OBLONGATA AND CEREBELLUM OF SQUIRREL MONKEY (SAIMIRI SCIUREUS)

Abstract— —The gross distribution of LDH and MAO was studied in a caudo-cranial series of 50 μ thick sections through the medulla oblongata and cerebellum. In general, LDH exhibited a stronger reaction in the neuropil and in the perikarya, whereas MAO showed moderate activity in the neurons and mild to moderate activity in the neuropil. The axonal processes and nerve fibres showed comparatively stronger MAO activity. The nuclei gracilis, cuneatus medialis and lateralis, cranial nerve nuclei, olivaris inferior, vestibularis and cochlearis nuclei showed particularly strong LDH and equally weak MAO activities. The lateral part of the formato reticularis myelencephali showed much more MAO than did the medial part, whereas the LDH reaction was uniformly strong. The reticularis lateralis showed uniformly strong LDH and very mild MAO activities.
In the cerebellar cortex, the MAO activity was concentrated in the molecular layer and nerve fibre layer, whereas LDH activity was particularly strong in the Purkinje cells and their processes in the molecular layer. The cerebellar nuclei showed strong LDH and weak MAO in the neutrons and stronger MAO and moderate LDH in the neuropil.     

Chemosensitive structures of the medulla oblongata participate in blood pressure regulation and belong to APUD-system

It was shown in 25 experiments on anesthetized spontaneously breathing and immobilized artificially ventilated cats that the cooling of the intermediate chemosensitive area of the ventral surface of medulla oblongata to 20-22 degrees C is followed by depressor reaction that is more pronounced after preliminary occlusion of the sinocarotid and vagus nerves. Two types of apudocytes were revealed in this brain area with the use of the histochemical and immunohistochemical techniques. The first type cells are typically nervous and contain noradrenaline. The second type apudocytes adjacent to the microvascular wall showed melatonin and its precursors. It is assumed that the cells detected participate in the arterial pressure control.     

Histopathological and ultrastructural observations of metacercarial infections of Diplostomum phoxini (Digenea) in the brain of minnows Phoxinus phoxinus

The spatial distribution and histopathological changes induced by metacercariae of the digenean trematode Diplostomum phoxini (Faust, 1918) in the brains of European minnows Phoxinus phoxinus (L.) from the River Endrick, Scotland, were studied by light and electron microscopy. Post-mortem examination of a sample of 34 minnows revealed that 50% (n = 17) of the population was infected with 13.7 +/- 2.6 (mean +/- SE; range 1 to 38) metacercariae per infected host. Serial histological sections of the infected minnow brains revealed that the metacercariae were unevenly distributed throughout the brain, with aggregations occurring in the cerebellum, the medulla oblongata and the optic lobes. In fish with highest intensities of infection, over 40% of the cerebellar area and about 30% of the medulla oblongata area were occupied by larvae. Metacercariae disrupt the integrity of brain tissue, with individuals being found in small pockets surrounded by cellular debris. Metacercariae were rarely encountered on the surface of the brain. Electron microscopic examination of infection sites revealed that the granular layer surrounding metacercariae was necrotic, exhibited nuclear degradation and was marked by vacuolation of the cytoplasm. Rodlet cells, the only inflammatory cell types recorded in this study, were found only in parasitized brains and in close proximity to the teguments of metacercariae. It is hypothesised that secretions released from the teguments of metacercariae are a counter response to protect the metacercariae from the fish brain's cellular defence mechanisms.     

Posterior Fossa Decompression Combined with Resection of the Cerebellomedullary Fissure Membrane and Expansile Duraplasty: A Radical and Rational Surgical Treatment for Arnold–Chiari Type I Malformation

This study aims to introduce a new surgical procedure for the treatment of Arnold–Chiari type I malformation (ACM-1) and to compare its effectiveness with the techniques described in previous studies. We performed the following procedures: foramen magnum decompression combined with the removal of both the atlanto-occipital membrane, extended resection of the cerebellomedullary fissure arachnoid membrane, and artificial duraplasty to enlarge the membranic posterior fossa without resecting the cerebellar tonsils and syringosubarachnoid shunting. There were 21 ACM-1 patients: 12 cases had osteo-compression on the cerebellar hemisphere, 18 cases had thickened adhered fabric ring that stretched from arachnoid membrane to cerebellar hemisphere, and 15 cases with syringomyelia. The patients were followed up for 6 months to 3 years after the surgery. All patients showed a remarkable recovery of syringomyelia. There were no morbidity or death related to the surgery. Most of ACM-1 patients, the osteo- and membrane compression on cerebellar hemisphere and tonsil were observed during the operation. Therefore, decompression of foramen magnum and posterior craniocervical combined with the removal of cerebellomedullary fissure arachnoid membrane and placement of an artificial dural graft should be considered as a comprehensive option of minimally invasive surgery and rational and radical treatment of ACM-1. Our experience showed that, by using our procedure, shunting becomes no longer necessary in the treatment of ACM-1-associated syringomyelia.