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.     

Morphometric study of the aortic and great pulmonary arterial pathways in human foetuses.

In prenatal and pediatric cardiovascular surgery knowledge of luminal diameters of the aortic and great pulmonary pathways is essential. The internal diameters of the aortic and great pulmonary pathways in 131 human foetuses (65 male, 66 female) were studied by means of anatomical, digital and statistical methods. During foetal development the absolute diameters revealed a linear increase. Correlation coefficients between these diameters and foetal age were statistically significant (P< or =0.05) for each age group and reached following values: r1 = 0.70 for the aortic bulb, r2 = 0.79 for the ascending aorta, r3 = 0.77 for the aortic isthmus, r4 = 0.79 for the descending aorta, r5 = 0.63 for the pulmonary trunk, r6 = 0.36 for the arterial duct, r7 = 0.46 for the right pulmonary artery and r8 = 0.49 for the left one. Diameters of the aorta and the pulmonary trunk indicated the relative increase in the values. A different tendency was observed for the internal diameters of the arterial duct and both pulmonary arteries, which were relatively decreased with increased foetal age. The largest diameter was observed in the arterial duct, the intermediate--in the right pulmonary artery and the smallest--in the left pulmonary artery. The cross-sectional area of the descending aorta was equal to the sums of the sectional areas of the aortic isthmus and the arterial duct (r9 = 0.97). The cross-sectional area of the pulmonary trunk was equal to the sums of the sectional areas of the both pulmonary arteries and the arterial duct (r10 = 0.91).     

The Effects of Castration and Hormone Replacement on the Cross‐Sectional Area of Pubococcygeus Muscle Fibers in the Female Rat

In this study, we analyzed the effect of ovariectomy and gonadal hormone replacement on the cross‐sectional area of pubococcygeus (Pcm) fibers. It was found that in comparison to intact animals, ovariectomized animals [for 2 or 6 weeks] had an increased cross‐sectional area average in Pcm fibers. Ovariectomy also reduced the percentage of fibers with smaller cross‐sectional area. In ovariectomized animals after 4 weeks of hormone replacement with an empty Silastic capsule or filled with testosterone propionate or dihydrotestosterone, significantly increased the cross‐sectional area average and the percentage of fibers with larger size. However, 17β‐estradiol but not estradiol benzoate treatment reduced the cross‐sectional area average and increased the percentage of Pcm fibers with smaller size. Progesterone did not have an effect on the cross‐sectional area of this muscle. We conclude that Pcm fibers of female rats are sensitive to gonadal hormones, and contrary to male castration, ovariectomy promotes an increase in their cross‐sectional area. Also, we discuss according to other studies that an external mechanism which lies within the neuromuscular periphery could also participate in the modulatory hormonal effect on mass or muscle fiber size. Furthermore, in this process, estradiol is likely to regulate the fiber cross‐sectional area growing produced by androgens. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.     

Craniofacial growth modified by the blood supply. 7. Dry weight of the skull and growth of the mandible

The dry weight of the skull and jaw bone increases faster in operated rats than in the controls during the fourth and 12 months, but their rates of growth do not differ in the 8th month. The distances measured on the mandible reveal definite sexual dimorphism in the development of the different lengths and heights, these distance being greater in the male rats. Growth in the length of the processes predominated over the growth of the body of the mandible. Local changes in the bone were observed at the points of origin and attachment of muscles.     

The cerebral basal arterial network: morphometry of inflow and outflow components

The aim of this project was to study how the morphology of the incoming and outgoing arterial components of the cerebral basal arterial network influence the blood flow to the brain. The cerebral basal arterial network consists of the circulus arteriosus cerebri anteriorly and the basilar artery posteriorly. Diameters of inflow vessels (bilateral vertebral and internal carotid arteries), connecting vessels (anterior communicating, basilar and bilateral posterior communicating arteries) and outflow vessels (anterior, middle and posterior cerebral arteries) were measured and cross‐sectional areas calculated in 51 cadaveric brain specimens. The individual and the average cross‐sectional areas of inflow arteries (51.43 mm²) were significantly bigger than the major outflow arteries (37.76 mm²) but smaller than the combined cross‐sectional areas of outflow (37.76 mm²) and connecting (25.33 mm²) arteries. The difference in the size of arterial cross‐sectional area and the presence of the connecting arteries in the cerebral basal arterial network provides a mechanism for lowering peaks in pressure, and demonstrates a function of the cerebral basal arterial network.     

Denervation and Castration Effects on the Cross‐Sectional Area of Pubococcygeus Muscle Fibers in Male Rats

The number of fibers in skeletal muscles changes little through life; however, the cross‐sectional area of its fibers is modified as result of denervation and in some muscles by castration. The pubococcygeus muscle (Pcm) participates in micturition and ejaculatory processes and its fibers cross‐sectional area is reduced in castrated rats, but denervation effects remained unknown. Here, we used a model in which unilateral denervation of this muscle in gonadally intact and castrated male rats, allowed us to explore the neural and gonadal hormone effects on the cross‐sectional area of its fibers. Denervation significantly reduced the mean cross‐sectional area values; likewise, the percentage distribution of its fibers. We found that castration had a greater effect than denervation. Castration resulted in a lack of fibers from 2,000 to 3,999 μm², while in denervation it was from 2,500 to 3,999 μm². It was interpreted that the castration effect was due to a lack of the direct gonadal hormone effect on muscle fibers, and to a reduction of the indirect hormonal action in its neuromuscular complex. In denervated Pcm of gonadally intact animals these effects were present; however, in denervated but castrated animals these were absent. Thus, combined surgeries resulted in the lowest mean cross‐sectional area values with a restricted fiber distribution from 500 to 1,499 μm². In conclusion, the study in this important muscle showed that cross‐sectional area of its fibers depends on neural and direct/indirect gonadal hormone effects. Anat Rec, 296:1634–1639, 2013. © 2013 Wiley Periodicals, Inc.     

Analysis of the arterial supply of the extrahepatic bile ducts and its clinical significance

The purpose of this study is to describe the arterial supply of the entire extrahepatic bile duct system. The cross‐sectional area of all arteries that supply the ducts is measured under an operating microscope in 50 adult cadavers injected with red latex through the aorta. The extrahepatic bile duct system is divided into four topographic portions: cystic duct and gallbladder, right and left hepatic ducts, bile (common) duct and including its supra‐retroduodenal parts, and the pancreatic and intraduodenal portions. The arterial supply to each portion is carefully detailed. The ducts are supplied by more than seven arteries, of which the major arteries are the cystic artery, posterior superior pancreaticoduodenal artery, right hepatic artery, and retroportal artery. Collectively they provide 94.5% of the blood supply to the ducts. Arteries form three types of anastomotic patterns on the walls of the ducts, suggesting that ductal incisions can be made in ways that least disturb the blood supply. The patterns are: a network, a longitudinal anastomotic chain, and an arterial circle. These data emphasize the importance of the arterial supply in biliary surgery and especially the treatment of hemobilia. Clin. Anat. 12:245–249, 1999. © 1999 Wiley‐Liss, Inc.     

Efficacy of vascular wall protection from atherosclerotic damage using various calcium antagonists

The authors studied the effect of various calcium antagonists--verapamil (VP) and Mg2+ (MgCl2) on the character of affection of the vascular wall ulcer conditions of prolonged hypercholesterolemia (HCE). The blood cholesterol (CS) content increased by the end of the 8th month of HCE to eight-fold the value in intact animals. The specific atherosclerotic changes in this case occupied approximately 80% of the area of the thoracic aorta whose functional properties changed essentially. The values of constricting responses of bands to noradrenaline (NA) was 45% of that in intact rabbits, the dilatating responses to acetyl choline (AC) and nitroglycerin (NG) were 20% and 35% of those in intact animals, respectively. Combination of HCE with daily VP injection (1 mg) led to a decrease in the area of affection of the aorta by 20%, which hardly affected the severity of HCE. A slightly more pronounced than in animals only with HCE (controls) was the response of bands to NA, AC, and NG (by 5, 30, and 15%, respectively). The protective effect of MgCl2 (200 mg/kg) was more significant--the affected area of the thoracic aorta reduced by 50% as compared to the controls, the constricting response to NA was maintained at a level exceeding the control level by 25%, the dilatating responses to NG and AC exceeded the control values 2 and 1.5 times, respectively, on the average. The severity of HCE diminished by 50%. The results of the study indicate that the organic and, in particular, the inorganic blocking agents of the calcium canals possess a marked angioprotective action and may be applied for the prevention of vascular atherosclerosis.     

Interactions between callosal,thalamic and associational projections to the visual cortex of the developing rat

Summary The patterns of callosal interconnections between the visual cortices of rats display considerable plasticity in response to various neonatal manipulations. In the present study, many neurones in the principal visual thalamic relay nuclei, the dorsal lateral geniculate nucleus (DLG) and to a lesser extent those in the lateral posterior nucleus (LP) were destroyed by injections of the neurotoxin — kainic acid — on the first day of postnatal life. Four weeks later, as demonstrated with the anterograde and retrograde transport of the enzyme horseradish peroxidase (HRP) injected into the occipital lobe of one hemisphere, callosally projecting neurones and terminals were distributed more widely in the retinotopically organized areas 17, 18a and 18b of the visual cortex ipsilateral to the lesioned visual thalamus than in unoperated control animals of the same age. By contrast, in the visual cortex contralateral to the lesioned visual thalamus the areal distribution of callosally projecting neurones and terminals was similar to that of the controls, that is, largely but not exclusively restricted to the common border of areas 17 and 18a. Both in unoperated and operated animals, cells in lamina V of several cytoarchitectonically defined areas that are not retinotopically organized (area 8 in the frontal lobe, area 29d in the retrosplenial limbic cortex and perirhinal areas 35/13 in the temporal lobe) also project to contralateral visual cortices. In areas 8 and 29d, the total numbers, laminar distributions and densities of labelled callosal cells both ipsilateral and contralateral to the kainate-injected visual thalamus were similar to those in the controls. However, in the temporal lobe, the areal distribution of the labelled callosal neurones was more extensive than that in the controls and labelled cells in areas 35/13 of the cortex contralateral to the kainate-lesioned visual thalamus merged with those in the neighbouring areas 20 and 36. By contrast, the areal distribution of associational neurones in area 18a and in nonretinotopically organized areas projecting to area 17 were very similar in controls and in operated animals (neonatal kainate lesion of the visual thalamus, neonatal section of the corpus callosum or both procedures combined). However, in operated animals, the labelled associational neurones projecting from the supragranular laminae (II/III) of area 18a to area 17 constituted a higher proportion of all cells than did those in the unoperated control animals. Thus, overall the number of associational neurones projecting from area 18a to area 17 was slightly increased by the experimental manipulations performed. The implications of these results concerning the mechanism(s) underlying the developmental changes in the distribution of commissural and associational neurones projecting to the rat's visual cortex are discussed.     

Distributions of adipocyte, blood vessel, and muscle fiber in human lateral petrygoid muscle during ageing.

The composition of adipocyte, blood vessel, and muscle fiber during ageing from 30 to 90 years of age was examined by a computer analyzing system in human lateral petrygoid muscle. The human lateral petrygoid muscle, the intramuscular connective tissue with adipocyte and blood vessel, displayed a specific change in morphology during ageing. Numerous adipocyte appeared around the blood vessel in the perimysium of the human petrygoid muscle from 60 years of age. The percentage and size of adipocyte and vein per 10,000 micron 2 of the cross sectional area in the muscle increased as well. However, the cross sectional area of muscle fiber was almost constant. The increase of adipocyte was related with changes of blood vessel and connective tissue in the perimysium.     

The oxygen environment of the arterial media in early rabbit hypertension

Hypertensive stimuli in experimental animals appear to cause early arterial wall hypermetabolism before hypertension is established and before histomorphic changes are marked. Hypermetabolism and the large diffusion distances for oxygen characteristic of large arteries imply that mural hypoxia could occur early in the disease but this has not been studied. Therefore, we measured aortic wall tissue oxygen distributions in male New Zealand White rabbits 2 weeks (1) after production of upper body hypertension by coarctation of the abdominal aorta, (2) after sham operation, and (3) in normal controls. As compared to normal and sham operated animals, blood pressure in the coarctation animals was significantly elevated from control levels, and the oxygen partial pressures were significantly reduced throughout the media. However, the hypoxic mural oxygen tensions in this relatively thin wall were not low enough to terminate classical respiration. At the time of measurement, moderate microscopic pathology was already present, including increased connective tissue production. The accompanying histomorphic changes are compatible with reports of extrarespiratory oxygen sensitivity of connective tissue metabolism.     

Calcineurin and Akt expression in hypertrophied bladder in STZ-induced diabetic rat

Diabetes causes significant increases in bladder weight but the natural history and underlying mechanisms are not known. In this study, we observed the temporal changes of detrusor muscle cells (DMC) and the calcineurin (Cn) and Akt expressions in detrusor muscle in the diabetic rat. Male Sprague-Dawley rats were divided into 3 groups: streptozotocin-induced diabetics, 5% sucrose-induced diuretics, and age-matched controls. The bladders were removed 1, 2, or 9weeks after disease induction and the extent of hypertrophy was examined by bladder weights and cross sectional area of DMC. Cn and Akt expression were evaluated by immunoblotting. Both diabetes and diuresis caused significant increases in bladder weight. The mean cross sectional areas of DMC were increased in both diabetic and diuretic animals 1, 2, or 9weeks after disease induction. The expression levels of both the catalytic A (CnA) and regulatory B (CnB) subunits of Cn were increased at 1 and 2weeks, but not at 9weeks. Expression of Akt was similar among control, diabetic, and diuretic rat bladder at all time points. In conclusion, diabetes and diuresis induce similar hypertrophy of detrusor muscle during the first 9weeks, indicating that bladder hypertrophy in the early stage of diabetes is in response to the presence of increased urine output in diabetes. Our results suggest that the Cn, but not the Akt signaling pathway may be involved in the development of bladder hypertrophy.     

The effect of a modified blood supply on the craniofacial growth of rabbits. 2. Masticatory muscles

After ligation of the right common carotid artery, the dry weight of the muscles of mastication on the ligated side did not differ from that of the control animals between the 45th and 225th d of life. On the opposite side, however, the muscles were in some cases significantly heavier than those of the control animals, particularly in male rabbits with ligated common carotid arteries. The methodical application of these results is proposed.     

Muscular strength in idiopathic haemihypertrophy.

Nine patients (age 8.9, range 6.5 to 9.5 years) with idiopathic haemihypertrophy were followed at six month intervals for two years. The isometric voluntary contraction strength of the elbow flexors and knee extensors was measured bilaterally, and expressed per unit of muscle and bone cross sectional area of the upper arm (elbow flexors) and of the mid thigh (knee extensors). In absolute terms, the hypertrophic side was always stronger, and the increase in strength was strongly correlated with the increase in limb size bilaterally (P less than 0.01). The hypertrophic limb always exerted greater isometric strength, but if strength was standardized for an anthropometric estimate of upper arm and mid thigh cross sectional area, the normal and hypertrophic side were not significantly different. The limb length discrepancy, when expressed in percentage, remained constant at approximately 3%.     

Cross‐sectional area of lumbar spinal muscles and vertebral endplates: a secondary analysis of 91 computed tomography images of children aged 2–20

Spinal muscle cross‐sectional area has been highly associated with spinal pathology. Despite the medium‐high prevalence of spinal pathology in children, there is very limited knowledge regarding muscle size and growth pattern in individuals younger than 20 years of age. The aim of this study is to analyze the change in size and symmetry of spinal muscles (erector spinae, multifidus, psoas and quadratus lumborum) in children 2–20 years of age. We studied reformatted images from 91 abdominal computed tomographic scans of children aged 2–20 years, from an existing imaging dataset. The cross‐sectional area of the muscles was bilaterally measured parallel to the upper endplate of the lumbar vertebrae L3–L5 and at true horizontal for S1. The cross‐sectional area of the upper vertebral endplate was measured at spinal levels L3–L5. Results were analyzed according to six groups based on children's age: 2–4 years (group 1), 5–7 years (group 2), 8–10 years (group 3), 11–13 years (group 4), 14–16 years (group 5) and 17–20 years (group 6). Vertebral endplate and spinal muscles cross‐sectional area increased with age. Two patterns were observed: Endplate, psoas and quadratus lumborum increased up to our 6th oldest age group (17–20), and multifidus and erector spinae reached their largest size in the 5th age group (14–16). The epaxial muscles (erector spinae and multifidus) reached their maximal cross‐sectional area before skeletal maturity (18–21 years of age). The hypaxial muscles (psoas and quadratus lumborum) continued to increase in size at least until spinal maturity. Contributing factors for the differences in developmental pattern between the epaxial and hypaxial muscles might include functional, embryological and innervation factors. In conclusion, this research is the first to describe the cross‐sectional area of spinal muscles in children. Future longitudinal studies are needed for further understanding of muscle development during childhood and adolescence. Level of evidence: level 2b, Retrospective cohort study.     

The arterial blood supply of the human fetal diaphragm

To gain a better understanding of the development of the human diaphragm, a study of the arterial supply was made in 20 fetuses. The Micropaque injection was injected either by an ascending route in the thoracic aorta or by a descending route in the left internal carotid below the ductus arteriosus. Two studies using diaphanization have displayed the diaphragmatic anastomoses. The phrenic and the intercostal a. seemed the most important to explain the diaphragm organogenesis.     

Craniofacial growth under the influence of the blood supply. 6. Metric studies of the skull

Cephalometric data show that the distances spanning several skull bones also have the highest growth rates. No sexual dimorphism can be observed in the skulls of animals that are six weeks old; such differences do not appear until after the fourth month of life. Allometric studies reveal a relative narrowing of the neurocranium and a relative broadening of the rostrum and zygomatic arch. The broadening of the zygomatic arch complex is related to the postnatal development of the masseter muscle. Vector analysis is used to demonstrate the growth activities of the different parts of the skull. Local changes in the bone during growth was observed in the regions of muscle origin and attachment.     

Simultaneous recording of urethral pressure and cross sectional area profile.

A new technique for simultaneously recording urethral closure pressure and cross sectional area profile is described. The cross sectional area of the urethra could be measured using the field gradient principle. The procedure was performed readily in male patients and the recordings can be graphically presented during measurement. A high degree of reproducibility using this method was obtained. Typical recordings of control subjects was well as patients with pathology were obtained using this technique. The results of this study show that the maximum urethral closure pressure obtained was 60.8 + 3.4 mmHg and functional profile length, 4.8 + 0.4 cm. Internal meatus cross sectional area was 0.67 + 0.04 cm2 and the minimum urethral cross sectional area was 0.12 + 0.02 cm2. This method has been shown to be readily applicable in measuring urethral closure pressure in males and can potentially be used as a tool of comparing the functional parameters of pressure with the anatomical value of diameter.     

Craniofacial growth modified by blood supply. 8. Discussion of normal cranial growth of the rat

The dimensions of the skull and the dry weight of the skull bones show definite sexual dimorphism. The dynamics of the growth in the skull dimensions and their vectorial presentation show that skull growth in Rattus norvegicus BERKENHOUT is most rapid between the 42nd d and the 4th month of life. This phase is followed by a phase of localized bone growth, which persists up to an age of 300 d. The faster growth of the viscerocranium leads to changes in the proportions of the skull. The relative positions of viscerocranium and mandible and the higher relative position of the dentures are similar to principle to those seen in man. Finally, the morphogenetic effect of the temporalis muscle together with that of the brain in the shaping of the skull are discussed.     

The skeletal muscle vascular supply closely correlates with the muscle fiber surface area in the rat

The skeletal muscle capillary supply (capillarity) dynamically changes in response to muscle conditions such as growth, atrophy, and hypertrophy. The capillary number-to-fiber ratio is reported to correlate closely with the muscle fiber cross sectional area. However, little information is available regarding the capillarity of neonatal and very young skeletal muscles. In this study, the vascular endothelium was reliably stained with an anti-PECAM-1 antibody, and relationships between the capillarity and muscle fiber parameters were analyzed. For assessment of the capillarity, we used the capillary length-to-fiber ratio, due to the presence of transversely running vessels. In young and adult rats, the capillary length-to-fiber ratio was proportional to both the muscle fiber cross sectional area and muscle fiber radius. However, when these data were analyzed together with data from neonatal and very young rats, the capillary length-to-fiber ratio correlated more closely with the muscle fiber radius than the muscle fiber cross sectional area in the tibialis anterior muscle. The capillary number-to-fiber ratio demonstrated results very similar to the capillary length-to-fiber ratio. During muscle atrophy after denervation, the number of capillaries was decreased in a non-apoptotic manner as revealed by electron microscopy, maintaining the close relationship between the parameters described above. In conclusion, capillarity was closely correlated with the muscle fiber radius (which represents the perimeter) during growth and atrophy. This indicates that the capillarity is linked to the muscle fiber surface area (which is determined by perimeter and section thickness), in agreement with the essential role of the cell membrane in the transport of materials by simple diffusion or active transport.