Action of neck accessory muscles on rib cage in dogs

To investigate the action of the neck accessory muscles on the rib cage, we stimulated the sternocleidomastoid and the scalenus muscles separately in supine anesthetized dogs. Hooks screwed into the sternum and ribs were used to measure their axial displacements and the changes in anteroposterior (AP) and transverse (T) diameters of the rib cage. We found that the sternocleidomastoid and scalenus muscles, when they contract alone, cause a large axial displacement of the sternum and the ribs in a cephalad direction and expand the rib cage along both its AP and T diameters. Opening the abdomen increased the cephalad displacement of the ribs and the expansion of the lower rib cage, particularly along its T diameter, but reduced the increase in lung volume. These experiments indicate 1) that the action of the sternocleidomastoid and scalenus muscles on the rib cage is essentially the consequence of a rotation of the ribs' neck axes, resulting from the cephalad displacement of the ribs, and 2) that the fall in abdominal pressure, almost certainly by acting through the zone of apposition of the diaphragm to the rib cage, has a deflationary action on the lower rib cage, more markedly so on its lateral than its anterior wall. The experiments also suggest that the fall in abdominal pressure prevents the diaphragm from moving cephalad and aids the neck accessory muscles in inflating the lungs.     

Myogenic and scalp signals evoked by midinspiratory airway occlusion.

A somatosensory potential that is evoked by transient added inspiratory load has previously been described (Davenport PW, Friedman WA, Thompson FJ, and Franzen O. J Appl Physiol 60: 1843-1848, 1986). This evoked potential is novel because it arises in response to a stimulus that also evokes a muscle response, and so this potential could contain myogenic components. The present study was undertaken to define the relationship between the scalp response and other physiological responses that are evoked by airway occlusion. Evoked signals were recorded from the scalp, scalenus anterior, masseter, and electrooculogram. Responses to a 200-ms midinspiratory occlusion were recorded in 12 healthy volunteers. Evoked responses were reliably recorded at C(3)-C(Z) and C(4)-C(Z) and from the skin overlying the scalenus anterior in 11 of these subjects. The onset latencies were 15.7 +/- 3.1 at C(3)-C(Z), 15.9 +/- 2.1 at C(4)-C(Z), and 17.6 +/- 5.5 ms at scalenus anterior. In nine subjects, the masseter response appeared to coincide with the mouth pressure trace, and this was interpreted as movement artifact. No consistent electrooculogram or frontal electroencephalogram response was recorded. Because of the similarity in onset latency at C(3)-C(Z), C(4)-C(Z), and scalenus anterior, it was concluded that the myogenic signal may contribute to the scalp response and should be viewed as a potential source of artifact in experiments of this nature.     

四川自贡中侏罗世峨眉龙—新种

记述了产自四川自贡大山铺中侏罗世峨眉龙属一新种——焦氏峨眉龙(Omeisaurus jiaoisp.nov.)。新种为大型蜥脚类恐龙,以如下特征区别于其他蜥脚类:前、中部背椎为典型的后凹型,后部背椎为双平型,背椎神经棘呈高大棒状,不分叉;尾椎为弱双凹型,第一尾椎不具扇形尾肋;第一脉弧短小且与第一尾椎关联;锁骨长大;肱骨和股骨细长而圆实;肱骨与股骨长度之比为0.83,尺骨与肱骨长度之比为0.72,胫骨与股骨长度之比为0.63。     

Vertebral and rib anatomy in Caperea marginata: Implications for evolutionary patterning of the mammalian vertebral column

The pygmy right whale, Caperea marginata, is a rare mysticete cetacean with an unusual suite of axial skeletal characters. Distally expanded first ribs, a long thorax with broadly overlapping vertebral transverse processes, plate‐like posterior ribs, and a short tail contrast with other cetaceans and suggest unique developmental patterning. Twenty‐four individuals of diverse ontogenetic age were available for analysis. Multiple, variable examples of incomplete rib fusion in dependent calves indicate that the first rib of adults is an ontogenetic fusion product of ribs 1 and 2. The composite rib articulates by way of its anterior (Rib1) component to the sternum and by way of its posterior (Rib2) component with thoracic vertebra 2. Thoracic vertebra 1 lacks rib articulations. When rib fusion is taken into account, the most frequent column formulas are C7T18L1Cd16–17 = 42–43 and C7T17L1Cd16–18 = 41–43. Thoracic and lumbar series are not reciprocal in count, arguing against their developmental linkage. Instead, parallel reduction in both lumbar and caudal counts supports the existence of neocete patterning in Caperea, as in all other living cetaceans. Ontogenetic vertebral column elongation is most marked in the posterior thorax, lumbos, and anterior tail. Vertebrae in these column regions are excellent predictors of total body length.     

现代华南人恒齿测量和齿尖形态观察研究

作者测量和观察了现代华南人1963个恒牙。结果表明,铲形上内侧门齿的出现率为91.8％;卡氏尖在M1中的出现率为23.8％,在M2中的出现率为1.6％。     

Action of the diaphragm on the rib cage inferred from a force-balance analysis

Displacements of the rib cage are determined by the intrinsic passive properties of the rib cage, rib cage musculature, pleural and abdominal pressures, and the diaphragm. The diaphragm's mechanical actions on the rib cage are inferred from a force-balance analysis in which the diaphragm is seen to cause expansion of the rib cage by pulling cephalad at its insertions on the lower ribs (insertional component) and by raising intra-abdominal pressure, which pushes outward on the diaphragm's zone of apposition to the rib cage (appositional component). Goldman and Mead suggested that the diaphragm, acting alone, could drive both the rib cage and abdomen on their passive characteristics. The force-balance analysis shows that the diaphragm's inspiratory action on the rib cage is less than predicted by Goldman and Mead, but that in the special circumstances of their experiment (low lung volumes), the appositional component is large and the rib cage can be driven close to its passive characteristics. The force-balance analysis is consistent with recent observations by other investigations and is incompatible with the model proposed by Macklem and colleagues and with the Goldman-Mead hypothesis. Experiments on three subjects produced data consistent with the force-balance analysis, showing that the inspiratory action of the diaphragm on the rib cage is greatest at low lung volumes.     

Homologies of the longissimus, iliocostalis, and hypaxial muscles in the anterior presacral region of extant diapsida

Homologies of muscles of the m. longissimus and m. iliocostalis groups in the dorsal and cervical regions, as well as those of the subvertebral muscles and mm. intercostales externi that continue from the dorsal into the cervical regions, in extant Diapsida are proposed based on detailed dissections and published accounts of lepidosaurs, crocodylians, and birds. The morphology of tendons and innervation patterns suggest that the avian "m. iliocostalis" in the dorsal region include the homologs of both m. longissimus and m. iliocostalis in non-avian diapsids. The conserved nature of the morphology of tendons in palaeognath birds also revealed that the avian mm. intertransversarii in the cervical region consist of muscles of the both m. longissimus and m. iliocostalis groups despite having been treated as a single series of muscles, and thus are not homologous with muscles of the same name in Lepidosauria or Crocodylia. The avian mm. inclusi that lie medial to mm. intertransversarii are homologous with mm. intercostales externi in Lepidosauria and mm. intercostales externi and m. scalenus combined in Crocodylia. Innervation patterns suggest that a muscle ("m. iliocostalis capitis") connecting the atlas rib and occiput in Crocodylia includes contributions from the subvertebral layer and m. cucullaris complex, and possibly m. iliocostalis as well. The present findings may serve as a basis for revising the currently used avian nomenclature so that it will reflect homologies of muscles with their non-avian counterparts.     

Geometry of human ribs pertinent to orthopedic chest-wall reconstruction

Orthopedic reconstruction of blunt chest trauma can aid restoration of pulmonary function to reduce the mortality associated with serial rib fractures and flail chest injuries. Contemporary chest wall reconstruction requires contouring of generic plates to the complex surface geometry of ribs. This study established a biometric foundation to generate specialized, anatomically contoured osteosynthesis hardware for rib fracture fixation. On human cadaveric ribs three through nine, the surface geometry pertinent to anatomically conforming osteosynthesis plates was characterized by quantifying the apparent rib curvature C(A), the longitudinal twist alpha(LT) along the diaphysis, and the unrolled curvature C(U). In addition, the rib cross-sectional geometry pertinent to intramedullary fixation strategies was characterized in terms of cross-section height, width, area, and cortex thickness. The rib surface exhibited a curvature C(A) ranging from 3.8 m(-1) in the anteromedial section of rib seven to 17.3 m(-1) in the posterior section of rib three. All ribs had in common a longitudinal twist alpha(LT), ranging from 41-60 degrees. The unrolled curvature C(U) decreased gradually from ribs three to five, and increased gradually with reversed orientation from rib six to nine. The cross-sectional area remained constant along the rib diaphysis. However, the medullary canal increased in size from 29.9 mm(2) posteriorly to 41.2 mm(2) in anterior rib segments. Results of this biometric rib characterization describe a novel strategy for intraoperative plate contouring and provide a foundation for the development of specialized rib osteosynthesis strategies.     

The diaphragm of the newborn infant: anatomical and ultrasonographic studies.

In the newborn infant, the diaphragm seems badly adapted to perform the burden of respiratory work. Indeed, due to the large angle of insertion on the rib cage and the small area of apposition, the flat diaphragm of the newborn infant seems better designed to suck in the rib cage rather than air. To better understand this paradox, and get insight in the structure-function relationship, the anatomical connections between the diaphragm and the rib cage were studied in 16 infants of various postmenstrual and postnatal ages. It was concluded (1) that the diaphragm inserts on the rib cage border only in the anterior costo-diaphragmatic triangle. From antero-laterally to posteriorly it inserts at increasingly greater distance from the rib cage border; (2) that the dorsal diaphragm ends its free course at the 11th rib and continues caudally as a spur ending between the 12th rib and the crista iliaca. From echographic studies of the right diaphragm with simultaneous measurement of the caudad displacement of the diaphragm and abdominal circumference change, the dynamics of the diaphragmatic movements could be better understood. It was concluded that, in contrast with the adult diaphragm, acting as a piston within the rib cage, the diaphragm of the newborn infant acts as a below moving mainly in the posterior part.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pattern and Time Course of Cleavages in Early Development of the Ovoviviparous Pond Snail, Sinotaia quadratus historica

The pattern and time course of cleavage during early development of the ovoviviparous pond snail, Sinotaia quadratus historica , in in vitro culture were investigated. The fertilized egg, 25–30 μm in diameter, underwent cleavage by repeated constriction and compaction as in blastocyst formation in mammalian embryos. The cleavage was slightly unequal and dextrally spiral, although a slight time lag in cleavages of blastomeres was observed after the 2nd cleavage. A small polar lobe was formed at the 1st cleavage, but not at the 2nd cleavage. Each cleavage proceeded very slowly under the experimental conditions, the 1st, 2nd, 3rd and 4th cleavages taking 22 hr or more, 9 hr and 10 hr, respectively. The cleavage pattern in in vitro cultures observed by light microscopy was confirmed by scanning electron microscopy.     

九种二变种山茶属植物的核型报道

本文报道了９种２变山茶属植物的核型．结果如下：Ｃａｍｅｌｉａｈｅｎｒｙａｎａ：２ｎ＝２ｘ＝３０＝２１ｍ＋８ｓｍ＋１ｓｔ;Ｃ．ｆｕｒｆｕｒａｃｅａ：２ｎ＝２ｘ＝３０＝２０ｍ＋１０ｓｍ;Ｃ．ｗａｒｄｉ：２ｎ＝２ｘ＝３０＝１８ｍ＋１１ｍ＋１ｓｔ;Ｃ．ａｎｌｕｎｇｅｎｓｉｓ：２ｎ＝２ｘ＝３０＝１９ｍ＋９ｓｍ＋２ｓｔ;Ｃ．ａｎｌｕｎｇｅｎｓｉｓｖａｒ．ａｃｕｔｉｐｅｒｕｌａｔａ：２ｎ＝２ｘ＝３０＝１９ｍ＋９ｓｍ＋２ｓｔ;Ｃ．ｐｙｘｉｄｉａｃｅａ：２ｎ＝２ｘ＝３０＝２０ｍ＋８ｓｍ＋２ｓｔ;Ｃ．ｐｙｘｉｄｉａｃｅａｖａｒ．ｒｕｂｉｔｕｂｅｒｃｕｌａｔａ：２ｎ＝２ｘ＝３０＝２１ｍ＋８ｓｍ＋１ｓｔ;Ｃ．ｂｒｅｖｉｓｔｙｌａ：２ｎ＝２ｘ＝３０＝１８ｍ＋１０ｓｍ＋２ｓｔ;Ｃ．ｌｅｐｔｏｐｈｙｌａ：２ｎ＝２ｘ＝３０＝２４ｍ（１ｓａｔ）＋４ｓｍ（１ｓａｔ）＋２ｓｔ;Ｃ．ｙｕｎｎａｎｅｎｓｉｓ：２ｎ＝２ｘ＝３０＝１８ｍ＋１０ｓｍ＋２ｓｔ;Ｃ．ｐｉｔａｒｄｉ：２ｎ＝２ｘ＝３０＝１８ｍ＋１２ｓｍ．其中,前７种２变种的核型为首次报道,比较前人的有关研究可以看出上述核型在种间较相似,以组为单位进行比较比种间比较具有更大的意义。     

Location-dependent variations in the material properties of the anterior cruciate ligament.

Our recent anterior drawer studies in human cadaveric knees [Guan and Butler, Adv. Bioengng 17, 5 (1990); Guan et al., Trans. orthop. Res. Soc. 16, 589 (1991)] have suggested that anterior bundles of the anterior cruciate ligament (ACL) develop higher load-related material properties than posterior bundles. This was confirmed when we reevaluated the axial failure data for these bundle-bone specimens from an earlier study [Butler et al., J. Biomechanics 19, 425-432 (1986)]. The purpose of this study was to determine, in a larger data set, if anteromedial and anterolateral bundles of the anterior cruciate ligament exhibit significantly larger load-related material properties than the posterior ligament bundles. Seven ACL-bone units from seven donors (the three tissues from the original study plus four new ones) were subdivided into three subunits, preserving the bone insertions. The subunits were failed in tension at a constant strain rate (100% s-1) and four material properties were compared within and between donors. The anterior bundles developed significantly larger moduli, maximum stresses, and strain energy densities to maximum stress than the posterior subunits. Moduli for the anterior vs posterior subunits averaged 284 MPa vs 155 MPa, maximum stresses averaged 38 MPa vs 15 MPa, and strain energy densities averaged 2.7 N m cc-1 vs 1.1 N m cc-1, respectively. No significant differences were found, however, among strains to maximum stress or between any of the other properties for the two anterior subunits. These results are important to the design of ligament replacements and suggest new experiments designed to distinguish in vivo force levels in these ACL bands, a possible reason for the material differences.     

In vitro analysis of kinematics and elastostatics of the human rib cage during thoracic spinal movement for the validation of numerical models

Neither kinematic nor stiffness properties of the rib cage during thoracic spinal motion were investigated in previous studies, while being essential for the accurate validation of numerical models of the whole thorax. The aim of this in vitro study therefore was to quantify the kinematics and elastostatics of the human rib cage under defined boundary conditions. Eight fresh frozen human thoracic spine specimens (C7-L1, median age 55 years, ranging from 40 to 60 years) including entire rib cages were loaded quasi-statically in flexion/extension, lateral bending, and axial rotation using pure moments of 5 Nm. Relative motions of ribs, thoracic vertebrae, and sternal structures as well as strains on the ribs were measured using optical motion tracking of 150 reflective markers per specimen, while specimens were loaded displacement-controlled with a constant rate of 1°/s for 3.5 cycles. The third full cycle was used to determine relative angles and strains at full loading of the spine for all motion directions. Largest relative angles were found in the main loading directions with only small motions at the mid-thoracic levels. Highest strains of the intercostal spaces were detected in the anterior section of the lowest fourth of the rib cage, showing compressions and elongations of more than 10% in all spinal motion planes. Elastostatic rib deformation was generally less than 1%. Rib-sternum relative motions exhibited complex motion patterns, overall showing relative angles below 2°. The results indicate that rib cage structures are not macroscopically deformed during spinal motion, but exhibit characteristic reproducible kinematics patterns.     

Genetic control of riboflavin biosynthesis in Pichia guilliermondii yeasts. The detection of a new regulator gene RIB81

The properties of mutants resistant to 7-methyl-8-trifluoromethyl-10-(1'-D-ribityl)-isoalloxazine (MTRY) were studied. The mutants were isolated from a genetic line of Pichia guilliermondii. Several of them were riboflavin overproducers and had derepressed flavinogenesis enzymes (GTP cyclohydrolase, 6.7-dimethyl-8-ribityllumazine synthase) in iron-rich medium. An additional derepression of these enzymes as well as derepression of riboflavin synthase occurred in iron-deficient medium. The characters "riboflavin oversynthesis" and "derepression of enzymes" were recessive in mutants of the 1st class, or dominant in those of the 2nd class. The hybrids of analogue-resistant strains of the 1st class with previously isolated regulatory mutants ribR (novel designation rib80) possessed the wild-type phenotype and were only capable of riboflavin overproduction under iron deficiency. Complementation analysis of the MTRY-resistant mutants showed that vitamin B2 oversynthesis and enzymes' derepression in these mutants are caused by impairment of a novel regulatory gene, RIB81. Thus, riboflavin biosynthesis in P. guilliermondii yeast is regulated at least by two genes of the negative action: RIB80 and RIB81. The meiotic segregants which contained rib80 and rib81 mutations did not show additivity in the action of the above regulatory genes. The hybrids of rib81 mutants with natural nonflavinogenic strain P. guilliermondii NF1453-1 were not capable of riboflavin oversythesis in the iron-rich medium. Apparently, the strain NF1453-1 contains an unaltered gene RIB81.     

Consanguineous marriages in the population of Sheikhupura (Punjab), Pakistan

This study was based on 1007 couples from the Sheikhupura population. The proportions of various parental relationships were: 0.3784 1st cousins, 0.0318 1st cousins once removed, 0.0784 double 2nd cousins, 0.1033 bradari distant relations, 0.3416 bradari, and 0.0665 unrelated parents. Mean paternal ages in unrelated couples are significantly higher than in 1st cousins, double 2nd cousins, and bradari relations. The differences in paternal and maternal ages are significantly higher in unrelated relations as compared to 1st cousins and double 2nd cousins. Procounced effects of consanguinity on parental deaths and neonatal deaths were observed in 1st cousin marriages compared to other relationships. Juvenile and infant deaths show comparatively less effects of consanguinity in 1st cousin marriages. Mean coefficient of inbreeding calculated for this population was 0.0271. Lethal gene equivalents calculated were 1.5424. The added risk of affected children in 1st cousins over that of unrelated parents was 4.82%. The results suggest that the deleterious genes show their effects more in the prenatal than in the postnatal period.     

Estimating fertility on the basis of birth-traumatic changes in the pubic bone

The relationship was studied between changes in the pubic bone brought about by pregnancy and birth and the number of births. Pairs of pubic bones were examined which were associated with a known number of births or miscarriages. We found no connection between the number of births and the formation of exostoses or the protrusion of the cranial edge of the facies anterior. The conical elongation of the Tuberculum pubicum in conjunction with a dorso-ventral reduction of the Pars symphysialis can be taken as an indication of several births. On the Facies posterior, only the formation of cavities tends to increase with the number of births.     

五种橐吾属植物的核型研究

首次报道了5种国产橐吾属植物的核型,结果如下：东俄洛橐吾(Ligularia tongolensis)核型为2n=58=32m 14sm 12st;侧茎橐吾(L.pleurocaulis)四川稻城居群核型为2n=58=24m 32sm 2st 3～5B,云南中甸居群核型为2n=58=36m 22sm;云南橐吾(L．yunnanensis)核型为2n=58=28m 30sm;叶状鞘橐吾(L．phyllocolea)核型为2n=58=30m 24sm 4st 1B;浅苞橐吾(L．cynthceps)核型为2n=58=24m 34sm。5种橐吾染色体数目都为58。在叶状鞘橐吾和四川稻城产侧茎橐吾中发现有B染色体存在,这在以前对橐吾属及近缘属植物的核型研究中未见报道。     

Nucleotide sequences at the boundaries between gene and insertion regions in the rDNA of Drosophila melanogaster

Ribosomal RNA genes interrupted by type 1 insertions of 1 kb and 0.5 kb have been sequenced through the insertion region and compared with an uninterrupted gene. The 0.5 kb insertion is flanked by a duplication of a 14 bp segment that is present once in the uninterrupted gene; the 1 kb insertion is flanked by a duplication of 11 of these 14 bp. Short insertions are identical in their entire length to downstream regions of long insertions. No internal repeats occur in the insertion. The presence of target site duplications suggests that type 1 insertions arose by the introduction of transposable elements into rDNA. Short sequence homologies between the upstream ends of the insertions and the 28S' boundaries of the rRNA coding region suggest that short type 1 insertions may have arisen by recombination from longer insertions.We have sequenced both boundaries of two molecules containing type 2 insertions and the upstream boundary of a third; the points of interruption at the upstream boundary (28S' site) differ from each other in steps of 2 bp. Between the boundary in the 0.5 kb type 1 insertion and the type 2 boundaries there are distances of 74, 76, and 78 bp. At the downstream boundary (28S' site) the two sequenced type 2 insertions are identical. The rRNA coding region of one molecule extends across the insertion without deletion or duplication, but a 2 bp deletion in the RNA coding region is present in the second molecule. Stretches of 13 or 22 adenine residues occur at the downstream (28S') end of the two type 2 insertions.     

Biosynthesis of Riboflavine in Saccharomyces cerevisiae: the Role of Genes rib1 and rib7

Haploid strains of Saccharomyces cerevisiae with mutations in two different rib genes were constructed. These strains were studied by tetrad analysis and by quantitative determination of accumulation products. The genes rib(1), rib(7), and rib(2) are not linked to each other. rib(1)-rib(7) strains and rib(1)-rib(2) strains exhibit the phenotypic properties of rib(1) strains. rib(7)-rib(2) strains show the phenotypic properties of rib(7) strains. The results support the conclusion that the genes rib(1) and rib(7) code for the first and second enzyme of the riboflavine pathway, respectively.