The effect of a modified blood supply on the craniofacial growth of the rabbit. 4. Skull and lower jaw asymmetry

Using a microscopic measuring method we were able to detect minor regions of asymmetry in the zygomatic arches of rabbits in which the common carotid artery had been ligated. These are considered in connection with the (also slight) asymmetric gains in the dry weight of the muscles of mastication in the ligated animals (see 2nd Bulletin).     

Craniofacial growth under the influence of blood supply. 10. Arthrosis of the temporomandibular joint

Unilateral and bilateral deformation of the temporomandibular joint was observed in young rats after unilateral ligature of the common carotid artery. They involved both the mandibular condyle and the mandibular fossa and were usually associated with a reduction in the dry weight of the masticatory muscles on the ligated side. This leads to the assumption that muscular atrophy is causally related to arthropathy of the temporomandibular joint. The methodological approach to induce changes in the temporomandibular joint may be used as a model of arthrosis of that joint.     

The effect of a modified blood supply on the craniofacial growth of rabbits. 3. Skull and mandible: general size development

This report deals with the growth of the skull and lower jaw after unilateral ligation of the common carotid artery in juvenile rabbits. No differences that could be attributed to the operation were found between the animals with ligated carotids and the control animals.     

Craniofacial growth under the influence of the blood supply. II. Skull scoliosis

After unilateral ligature of the common carotid artery in young rats, the rostrum was observed to shift towards the ligated side. The scoliosis was combined with arthropathic changes in the temporomandibular joint. The deflection of the rostrum is situated in the region of the right premaxillar bone. It is assumed that the scoliosis is caused by reduction of the blood flow to the frontonasal sutures because the terminal branches of the infraorbital artery have no collaterals. Moreover, the reduction in the blood supply also leads to disturbance of the muscular function and thus to a reduction in growth stimuli to the frontonasal sutures.     

The influence of blood supply on craniofacial growth. 4. Reactions of the jaw musculature

The dry weight of the chewing muscles differ distinctly between male and female. In rats aged 8 to 12 months the dry weight of the chewing muscles after ligature of the carotid artery was lower on the side of the ligature. Necrotic fibres were occasionally found in the masseter muscle on the ligature side. Morphometric investigation of the masseter muscle fibres revealed no significant differences between the 2 sides in the operated rats. Since the rats were relatively young when the commune carotid artery was ligatured unilaterally, the consequences of the initially reduced blood supply to the chewing muscles on the right side could be compensated for rather well, mainly by the enlargement of previously existing anastomoses. Our quantitative and histological studies nevertheless show that muscular dysbalance of the masticatory apparatus was severe.     

Craniofacial growth influenced by blood supply. 1. Collaterals and anastomoses following unilateral ligation of the common carotid artery

The influence of the blood supply on craniofacial growth was investigated in 396 albino rats (Rattus norvegicus Berkenhout). This was done by blocking the right common carotid artery of animals aged 42 d. The rats were slaughtered at previously specified intervals after the operation. The ligature led to dilation of the other major arteries of the neck. Numerous collaterals and anastomoses were also formed. These occurred on the ligature side in the flow region between the proximal and distal stumps of the right common carotid artery, between the flow regions of the right external carotid artery and the right vertebral artery and between the flow regions of the right subclavian artery and the right external carotid artery. Further anastomoses arose between the arteries of the other side, i.e. the rostral thyroid artery, lingual artery, submental artery and labial mandibular artery.     

Craniofacial growth modified by blood supply. 2. Changes in arterial cross sections and arterial blood supply

The cross sectional areas of arteries were calculated from their measured thicknesses. The monthly increase in size of the cross sectional area of the aorta is higher in both the controls and the operated animals between the 6th week and 4th month of life than during the subsequent period. The rate at which the cross sectional area of the aorta increased in operated animals was about twice that observed in the controls. The left common carotid artery increased its cross section in the operated animals most rapidly up to the fourth month. The cross sectional areas of all anastomoses increased five-fold by the 12th month of life. The quantities of blood flowing correlated closely with the angiometric values.     

Monocyte adhesion and changes in endothelial cell number, morphology, and F-actin distribution elicited by low shear stress in vivo.

Left common carotid arteries of New Zealand white rabbits were ligated rostral to origin of the thyroid artery to reduce flow in the carotid upstream of this branch, and the vessels were examined 5 days later. Estimates of mean shear stress in the upstream carotid artery indicated a decrease of 73% (from 12.1 +/- 1.6 dynes/cm2 to 3.26 +/- 0.58 dynes/cm2). The contralateral common carotid artery carried collateral flow and experienced a 170% increase in shear stress (from 11.3 +/- 1.6 dynes/cm2 to 30.5 +/- 4.6 dynes/cm2). There was an adaptive reduction in the diameter in the left common carotid artery (low shear) from 2.07 +/- 0.06 mm to 1.75 +/- 0.12 mm, but the diameter of the right carotid was unchanged. Fluorescence microscopy and scanning electron microscopy of endothelium exposed to low shear revealed attachment of leukocytes (5.02 +/- 1.59 cells/mm2, mean +/- SE) that were identified as monocytes using the monoclonal antibody HAM 56. Laser confocal microscopy demonstrated that they were migrating across the endothelial cell monolayer. Fluorescence microscopy and scanning electron microscopy of left common carotid artery (low shear) also revealed cell morphology suggestive of endothelial cell desquamation. Endothelial cell loss was confirmed by morphometric determination of cell number (1.29 +/- 0.13 x 10(4) cells/mm length in experimental animals versus 1.71 +/- 0.08 x 10(4) cells/mm length in sham-operated animals). This endothelial cell loss may be an adaptation to a narrowing of carotid arteries exposed to low shear, which reduces luminal surface area of the vessel. Staining of F-actin with rhodamine phalloidin showed that endothelial cells exposed to low shear were less elongated and had fewer stress fibers than normal cells. By contrast, increasing shear stress by two- to threefold caused an increase in the number of stress fibers and a reduction in peripheral actin staining. Distal carotid ligation provided a consistent and well-defined in vivo technique for manipulating shear stresses imposed on a large population of endothelial cells.     

Craniofacial growth under the influence of blood supply. 9. Skull and mandibular growth after carotid ligation

Unilateral ligature of the common carotid artery leads to a reduction in the size of the zygomatic arch complex in rats aged 8 and 12 months. Skull growth is accelerated during the 4th and 12th month in operated animals, so that these animals have large skulls than the controls at maturity. Comparison with the literature suggests that this is a result of over-compensation of the blood supply after the ligature. Increased availability of arterial blood also leads to greater axial growth of tubular bones. The lack of skull growth during the 8th month is discussed. The biomathematical methods of analysis used for these studies are of only limited validity for the observation of skull growth.     

The prelymphatic pathways of the brain as revealed by cervical lymphatic obstruction and the passage of particles.

Light and electron microscopy was used to examine portions of the brain, the circle of Willis, and the internal carotid arteries of normal cats and rabbits, of sham-operated ones, and of those whose cervical lymphatics had been ligated. Carbon was injected into the cerebral cortex of some lymphoedematous animals. It was found that lymphatic ligation produced oedema of the brain, and a dilatation of the prelymphatic spaces around the vessels. Carbon was traced in these from the injection site, around the minor and major vessels, in the adventitia of the internal carotid artery, entering lymphatics adjacent to it, and finally in the draining lymph nodes. The oedema and dilated spaces were not present in the control animals. This was taken to indicate that there is a continuous system of non-endothelialized spaces and potential spaces-the prelymphatics-draining the brain into the cervical lymphatics. The protein in these spaces appeared to be increased if the lymph-oedema had lasted three weeks as compared to 24 hours, indicating that one of the major roles of this system is the removal of protein.     

一种颈总动脉部分结扎-内膜新生模型的制备

目的 探讨一种左颈总动脉部分结扎后诱导血管重构（内膜新生）的方法。方法 8周龄雄性C57BL/6 J小鼠40只,随机分为6组：正常组（WT）、假手术组（sham）、术后4周、8周、10周和12周组。手术结扎左颈总动脉（LCA）远心端4个分支中的颈内、颈外和枕动脉,保留甲状腺上动脉,造成左颈总动脉血管内膜新生和血管重构。术后观察小鼠体重和饲料的消耗情况;HE染色观察血管形态学变化;天狼猩红染色观察血管胶原纤维聚集情况。结果 除正常组小鼠外,其他组小鼠术后1～2 d体重和饮食量均降低,第3天开始上升,假手术组小鼠第2天开始上升;HE染色表明,假手术组和正常组小鼠LCA均未形成新生内膜,部分结扎手术后4、 8、10和12周组小鼠LCA均出现内膜和中膜层的增厚、管腔狭窄等。右侧未结扎的颈总动脉无内膜增厚,但出现了管腔增大;天狼猩红染色显示,内膜和中膜增生部分有胶原积聚。结论 左颈总动脉部分结扎可以建立小鼠动脉内皮损伤模型并伴有明显的内膜新生。     

采用高脂饲料加空气干燥术建立颈动脉粥样硬化动物模型

目的:利用高脂饮食加空气干燥术建立一种稳定、重复性好、有较典型动脉粥样硬化病理改变的动物模型。方法:32只日本大耳白兔随机分为模型组(n=24)、对照组(n=8)。模型组给予高脂饲料喂养加空气干燥术,术中结扎左侧颈动脉分支血管,对照组正常饲料喂养,分别于术后第2、4、8、12周处死动物。取颈动脉组织切片HE染色,光镜下观察。结果:(1)75%兔颈总动脉存在细小血管分支,暂时结扎侧支血管后干燥效果更好。(2)对双侧颈动脉实施手术,结扎左侧分支,成模率更高。部分斑块显示出不稳定性。结论:采用改进后高脂饮食加空气干燥术可成功建立兔颈动脉粥样硬化模型,其病理特点适合于目前临床研究。     

Stabilizing neuromuscular contacts reduces motoneuron death caused by paralysis of muscles in neonatal rats.

Transient paralysis of the soleus muscle in neonatal rats leads to permanent muscle weakness, loss of muscle fibres and motoneuron death. Application of leupeptin, an inhibitor of a calcium-activated neutral protease, to the neuromuscular junction is known to enhance the maintenance of neuromuscular contacts during development and axonal sprouting. Here, we show that treatment of soleus muscles with leupeptin as they recover from a period of paralysis rescues motoneurons that would otherwise die. The number of motoneurons to the soleus muscle was established by retrograde labelling with horseradish peroxidase eight to 10 weeks after recovery from paralysis. There were only 38.4 (+/-2.8 S.E.M., n=5) motoneurons innervating the soleus muscle that had been paralysed with alpha-bungarotoxin, compared to 58.2 (+/-3.1 S.E.M., n=5) to the control untreated soleus. Thus, the number of motoneurons to the soleus muscle on the alpha-bungarotoxin-treated side was 66.9% (+/-6.2% S.E.M., n=5) of the control side. In those animals where paralysis of the soleus muscle was followed three days later by treatment with leupeptin, the number of labelled motoneurons on the treated side of the spinal cord was 61.5 (+/-4.6 S.E.M., n=4) and that on the contralateral untreated control side was 59 (+/-3.8 S.E.M., n=4). This improvement in motoneuron survival in the leupeptin-treated animals is also confirmed by counts of the number of motor units in the soleus muscle obtained by recording muscle tension. In animals that had their soleus muscles paralysed at birth, only 21 (+/-0.7 S.E.M., n=5) motor units were present, compared to 30 motor units in control muscles. When the paralysed soleus muscle was subsequently treated with leupeptin, the number of remaining motor units in the muscle was 29.8 (+/- 1.0 S.E.M., n=5). In addition, the force output of the soleus muscles that had undergone a period of neonatal paralysis was calculated for both the NaCl- and leupeptin-treated animals. The results showed that paralysis at birth results in a reduction in weight and force output of the soleus muscle, which is not improved following treatment with leupeptin. This study shows that application of leupeptin to the soleus muscle after alpha-bungarotoxin-induced paralysis rescues motoneurons to the soleus that would otherwise die. This effect is most likely due to stabilization of their neuromuscularjunctions.     

Effects of transient hypoxia on internal intercostal muscle activity in vagotomized rabbits

The effects of transient hypoxia on the responses of internal intercostal (IIC) muscle activity before and after surgical denervation of the carotid sinus nerves were studied in the bilaterally vagotomized rabbits. Bilateral vagotomy caused a complete inhibition of IIC activity in 11 of 13 animals. In the vagotomized animals with no expiratory activity in the IIC muscles, lung inflations with low O2 gas mixture (6% O2 in N2) produced an increase in IIC activity, whereas these excitatory effects were remarkably reduced after sectioning the carotid sinus nerves. In addition, the effects of lung inflation with low O2 gas mixture (6% O2 in N2) on carotid chemoreceptor activity were also studied in the vagotomized rabbits. Lung inflations with hypoxic gas caused an increase in carotid chemoreceptor activity. These results indicate that in the absence of proprioceptive input from the lungs, hypoxic stimulation of the carotid chemoreceptors is capable of activating the expiratory activity in the IIC muscles.     

Early changes of experimentally induced cerebral aneurysms in rats. Light-microscopic study.

The changes of the anterior cerebral artery/olfactory artery junction, one of the favorite sites of aneurysm formation, in rats treated with unilateral ligation of the common carotid artery and renal hypertension were investigated by light microscopy. The initial changes of aneurysm occurred not at the apex itself, but on the distal side of the major branch adjacent to the apex, at the intimal pad and the neighboring distal portion. Here the internal elastic lamina showed various degenerative changes and disappearance. The neighboring distal portion adjacent to the intimal pad showed a shallow depression associated with a thinning of the media due to a decrease of medial smooth muscle cells in number even in some control animals. Such degenerative changes of the internal elastic lamina and medial smooth muscle cells caused by hemodynamic stress due to branching structure, including intimal pads, augmented by the experimental treatment, are supposed to be the basis for aneurysm formation.     

大鼠短暂性局灶性脑缺血模型的改进

目的:改进大鼠短暂性(<2小时)局灶性脑缺血模型的制作方法。方法:采用雄性SD大鼠24只,分实验组和对照组,实验组又分三组,用线栓法使大脑中动脉(MCA)分别缺血15min、30min、60min,每组6只;假手术对照组6只。所有实验动物均采用乙醚麻醉,在手术过程中用5-0丝线结扎颈外动脉,在结扎的近侧剪断颈外动脉或其分支-枕动脉,经颈外动脉断端或枕动脉将4-0单丝尼龙线插入颈内动脉直至大脑中动脉起始处。假手术对照组动物线栓插入颅内但不达大脑中动脉起始处。术后即可观察动物行走时是否转圈。结果:所有实验组动物都及时观察到动物行走时出现转圈的表现,符合实验的入组标准。假手术对照组动物术后没有观察到转圈的表现。结论:短暂性局灶性脑缺血模型制作方法经改进更易于制作、可行性更强、可信度更高且有利于进一步推广运用。     

Ingestion of low concentrations of sucrose or hydrochloric acid solutions accelerates mortality in rats with cholestatic liver disease

Mortality rates were monitored in bile duct ligated (BDL) rats which were consuming flavor solutions in addition to water and chow. Following ligation of the common bile duct, animals were offered a single concentration of a flavor solution (200 mM NaCl; 400 mM sucrose; 100 mM urea; 5 mM HCl) in addition to water. During three weeks postligation, mortality rates were compared between groups of ligated animals consuming either one of the taste solutions or consuming only water. Within the first five days postligation, mortality was 70% in ligated animals drinking HCl and 50% in animals consuming sucrose, compared to 30% for urea, 10% for sodium chloride and 0% in animals drinking only water. Total mortality of ligated rats consuming HCl or sucrose solutions was significantly increased compared to animals consuming only water. The results suggest that consumption of low concentrations of sucrose or HCl solutions during the initial stages of liver disease in BDL rats may drastically accelerate their mortality rate.     

Skull deformities following unilateral mandibular dysfunction. 1. General review of secondary changes

Communications 1 to 5 will deal with the significance of the masticatory muscles as a local factor affecting the shaping of the skull. The reports are based on experiments with dogs (Beagles) on which unilateral partial resection of the mandible was performed at different ages. The animals were slaughtered one year after the operation. 1st Bulletin: More or less severe scoliosis was observed in all skulls and proved to be the principal secondary change. The deviation was found to be particularly great in the region of the viscerocranium in all cases. Other findings include a flattening of the zygomatic arch and the linea temporalis on the operated side, close spacing of the front teeth, and deformation and reduction in size of the temporomandibular joint socket.     

颈动脉分叉区域的神经血管解剖及其对颈动脉内膜剥脱术的临床意义

目的　通过对尸体标本的颈动脉分叉区域内的神经、血管进行解剖研究,为安全有效地开展颈动脉内膜剥脱术提供形态学依据及解剖学基础。 方法 选取20例（40侧）无明确心、脑血管疾患的尸体解剖标本（男11例、女9例）,采取颈动脉内膜剥脱术式入路对颈动脉分叉区域内的神经、血管进行解剖研究,明确血管和神经的形态学及结构特点。 结果 颈总动脉分叉部形态可分为Ⅰ、Ⅱ、Ⅲ型,分别占比为10%、52.5%、37.5%。分叉位置以甲状软骨为界,左侧颈总动脉分叉部高度在其上缘以上、平上缘和上缘以下的占比分别为55%、37.5%、7.5%;相较之下右侧分别为62.5%、27.5%、10%。男性颈总、颈内、颈外动脉内径均大于女性（P<0.05）;男性颈动脉分叉角度大于女性（P<0.05 ）。双侧颈总、颈内、颈外动脉内径相比无统计学意义（P>0.0 5）;左侧颈动脉分叉角度大于右侧（P<0.05）。 结论　通过对颈动脉分叉区域内的神经、血管进行解剖研究,对颈动脉内膜剥脱术术中血管与神经的保护具有重要的临床意义。