Nasal capsular cartilage is required for rat transpalatal suture morphogenesis

In the cranial vault, suture morphogenesis occurs when the growing cranial bones approximate and overlap or abut one another. Patency of developing sutures is regulated by the underlying dura mater. Once cranial sutures form, bone growth proceeds from the sutures in response to growth signals from the rapidly expanding neurocranium. Facial sutures do not develop in contact with the dura mater. It was therefore hypothesized that facial suture morphogenesis and bone growth from facial sutures are regulated by tissues with an equivalent role to the dura mater. The present study was designed to test this hypothesis by characterizing the morphology and growth factor expression in developing transpalatal (TP) sutures and their surrounding tissues, and then assessing the role of the overlying nasal capsular (NC) cartilages in maintaining suture patency. TP sutures develop as overlapping sutures, similar to cranial coronal sutures, and expression of Tgf-betas in TP sutures was similar to their distribution in cranial coronal sutures. To establish whether NC cartilages play a role in regulating TP suture morphogenesis, fetal rat TP sutures were cultured with associated attached NC cartilages or with NC cartilages removed. Sutures cultured for upward of 5 days with intact NC cartilages remained patent and maintained their cellular and fibrous components. However, in the absence of NC cartilages, the cellular nature of the sutures was not maintained and they became progressively acellular, with bony bridging across the suture. This finding is similar to that for cranial vault sutures cultured in the absence of dura mater, indicating that NC cartilages play an equivalent role to dura mater in maintaining the patency of developing sutures. These studies indicate that tissue interactions likely regulate morphogenesis of all cranial and facial sutures.     

Cranial suture complexity in white-tailed deer (Odocoileus virginianus)

Neurocranial expansion and mastication are commonly implicated as the two major biomechanical factors affecting suture morphology. In deer the antlers provide an additional source of biomechanical stress acting on the skull. Equivalent stresses are not found in females, who lack antlers. We analyzed the complexity and interdigitation of the interfrontal and coronal sutures that surround the antler-bearing frontal bones of (n = 67) white-tailed deer (Odocoileus virginianus) to 1) evaluate changes in suture morphology throughout ontogeny, and 2) test the hypothesis that male deer have more complex sutures than females. Two methods were used to quantify suture morphology: fractal analysis and length-ratios (actual suture length divided by direct straightline length). Both techniques produced similar results, although the two methods cannot be considered equivalent. Suture complexity increases markedly throughout ontogeny, but appears to level off after animals have reached adulthood. Cranial size in males, but not females, continues to increase in adults. No significant increase in suture complexity with age in the adult cohort was detected. While deer are highly dimorphic in size and the presence of antlers, no significant differences existed between males and females for any measure of suture complexity. No consistent patterns emerged between suture complexity and skull size or antler characteristics. The presence of antlers appears to have a minimal effect on suture complexity in white-tailed deer. Factors that may contribute to the lack of dimorphism in suture complexity are discussed.     

具过顶古口缝的沟鞭藻化石记录及古生态

本文列举了大量具过顶古口缝的沟鞭藻囊孢在海相和非海相沉积中的记录,指出具有一构造的沟鞭藻囊孢可以细分成两个亚类,分别代表晚白垩世从海相澡类家族中分化出的两个分支：一个以Ｐａｌａｃｅｐｅｒｉｄｉｎｉｕｍ为代表,具有ｂｉｐｅｓｉｏｉｄ型反映板式;另一支以Ｓａｅｐｔｏｄｉｎｉｕｍ为代表,具有ｂｉｐｅｓｉｏｉｄ或ｃｉｎｃｔｉｏｉｄ型反映板式,前者在晚白垩世开始向淡水环境迁移,但仍有部分留在海水中,一直延续     

Effect of low-intensity millimeter wave electromagnetic radiation on regeneration of the sciatic nerve in rats

The effect of low-intensity millimeter wave electromagnetic radiation (MWR) on regeneration of the rat sciatic nerve after transection and microsurgical reapproximation was examined. Rats were exposed to 54 GHz MWR at a power density of 4 mW/cm². It was found that MWR treatment of the femoral skin in the area of suture accelerated the regeneration of nerve fibers. At the twentieth postoperative day, the MWR-treated animals had a 32% increase in the regeneration distance compared to the control animals. The conduction velocity showed a 26% increase in the MWR-treated animals. © 1996 Wiley-Liss, Inc.     

Two new Raabena species and a new Pararaabena species (Ciliophora,Entodiniomorphida) with redescriptions of Raabena bella and Pararaabena dentata

The genera Raabena and Pararaabena (Ciliophora, Entodiniomorphida, Blepharocorythidae) were monospecific, and their type species are Raabena bella Wolska, 1967 and Pararaabena dentata Wolska, 1968. They have been found in Asian elephants and closely resemble each other: ovoid and laterally compressed body; non-retractable adoral ciliary zone; funnel-shaped vestibulum; three non-retractable somatic ciliary arches. Furthermore, the positional relationship between the vestibular ciliary zone and the anterior dorsal ciliary zone identifies Raabena and Pararaabena: these two ciliary zones are connected in Raabena while they are separated in Pararaabena. While investigating entodiniomorphid ciliates of Asian elephants, the author often encountered ciliates similar to Raabena bella but with a sinuous body or with a small body and ciliates similar to Pararaabena dentata but with a slender body or with no or two caudal lobes. In this study, their general morphology and infraciliature were compared to R. bella and P. dentata to know whether they are new species or morphological variations in a species. As a result, the present study redescribed R. bella and P. dentata, and described R. sinuosa n. sp., R. bellafilia n. sp., P. gracilis n. sp., and morphotypes of P. dentata.     

New insights on the reparative cells in bone regeneration and repair

Bone possesses a remarkable repair capacity to regenerate completely without scar tissue formation. This unique characteristic, expressed during bone development, maintenance and injury (fracture) healing, is performed by the reparative cells including skeletal stem cells (SSCs) and their descendants. However, the identity and functional roles of SSCs remain controversial due to technological difficulties and the heterogeneity and plasticity of SSCs. Moreover, for many years, there has been a biased view that bone marrow is the main cell source for bone repair. Together, these limitations have greatly hampered our understanding of these important cell populations and their potential applications in the treatment of fractures and skeletal diseases. Here, we reanalyse and summarize current understanding of the reparative cells in bone regeneration and repair and outline recent progress in this area, with a particular emphasis on the temporal and spatial process of fracture healing, the sources of reparative cells, an updated definition of SSCs, and markers of skeletal stem/progenitor cells contributing to the repair of craniofacial and long bones, as well as the debate between SSCs and pericytes. Finally, we also discuss the existing problems, emerging novel technologies and future research directions in this field.     

Lower Cretaceous gastropods from the Qayen area,Eastern Iran

Four gastropod genera are newly recorded from Lower Cretaceous deposits of the Qayen area, Eastern Iran. Based on the paleoecological interpretation of the faunal assemblage and especially on the newly identified gastropods, a shallow temperate marine environment is suggested for the fossil-bearing carbonate rocks. The gastropod assemblage shows a typically Tethyan composition comparable to those already reported from the Caucasus and Eastern Europe.     

Achieving Better Estimates of Greater Sage-Grouse Chick Survival in Utah

Abstract: Declining sage-grouse (Centrocercus urophasianus) populations may be characterized by poor recruitment largely attributed to low chick survival. However, few published studies have explicitly examined factors that influence chick survival. We used a suture method to radiomark 1-2-day-old sage-grouse chicks (n = 150) in 2005-2006 on Parker Mountain in south-central Utah, USA, and monitored their survival to 42 days. We modeled effects of year, hatch date, chick age, brood-female age, brood-mixing, and arthropod abundance on chick survival. Our best model revealed an average survival estimate of 0.50 days to 42 days, which is the highest level ever documented for this long-lived species. Brood-mixing occurred in 21% (31/146) of chicks and 43% (18/42) of broods we studied. Moreover, yearling females had more chicks leave their broods than did adults. We found that survival may be higher among chicks that switch broods compared to those that stayed with their natal mother until fledging. Thus, brood-mixing may be an adaptive strategy leading to increased sage-grouse chick survival and higher productivity, especially among chicks born to yearling females. Our findings also indicate that arthropod abundance may be an important driver of chick survival, particularly during the early brood-rearing period and, therefore, sage-grouse populations may benefit from a management strategy that attempts to increase arthropod abundance via brood habitat management.     

Is the complexity of the human sagittal suture related to the size of the temporal muscle?

We have tested the hypothesis that temporal muscle size determines the degree of interdigitation of the human sagittal suture by comparing male and female skulls of Europeans and Australian aborigines. Temporal muscle length, area of the temporal aperture and estimated muscle volume were greater in males than in females of each racial group. Sexual dimorphism of the complexity of the sagittal suture was not confirmed in either race. However, the suture was less complex in aborigines than Europeans despite the volume of the temporal muscle being larger in the former group. We conclude, therefore, that although the morphology of the sagittal suture is an epigenetic character, it is not mechanically influenced by muscle size. A simple quantitation of suture form may however be useful in assigning unknown skulls to a particular race.