The Question of a Vomer in Brachiopterygian Fish

Abstract The term vomer was coined over four centuries ago to denote one of the 23 bones normally comprising an adult human skull. As time went on more and more craniates were designated vomerate. To date, however, the issue as to whether brachiopterygian fish are or are not vomerate has remained unresolved. Those who consider these fish to be vomerate have suggested at least three different palatal bones as the homologue of the human vomer. Examination of embryological material of Polypterus senegalus shows that this brachiopterygian actually develops a vomer which eventually becomes united indistinguishably with the anterior part of the parasphenoid. The vomer is suggested to have arisen through the fusion of dental plates belonging to a supplementary set of buccopharyngeal denticulate bones. The other subethmoidal bones of the brachiopterygian palate seem likely to be derivatives of the tooth plates which originally were applied to the first two pairs of infrapharyngeals. When these endoskeletal elements were put to use for encapsulation of the organs of smell early in craniate phylogeny, some of the tooth plates that covered their inner surfaces fused to provide anterior palatal bones. Identified at one time or another as vomers, these bones are here termed glochinals and dacnils.     

Intratumoural light distribution in an experimental mouse tumour irradiated by a diffuse-light irradiator compared with unilateral helium-neon light for photodynamic therapy

Investigations on dosimetry in photodynamic therapy (PDT) of experimental mouse tumours transplanted into the right hind leg revealed a significant variability in the fluence rate reaching tumour cells in different parts of the tumour when irradiated by a 50 mW collimated He-Ne laser. Based on intratumoural fibre-optical light measurements, a new irradiation source was constructed, in which variability in the radiant energy fluence rate between different parts of the solid tumour was reduced. The new diffuse-light irradiator was constructed basically from two concentric water chambers surrounded by three linear 3000 W xenon flash lamps. The outer chamber was an optical band filter, and the inner chamber contained a light-dispersing solution of lipid droplets which created an isotropic light field in which the tumours were submerged for PDT. Compared with unilateral He-Ne laser irradiation, an enhancement factor of 7.3 in radiance was obtained for the diffuse-light irradiator measured in the tumour. The new apparatus provides a nearly isotropic light field for in vivo experimental PDT.     

The Evolutionary Origin and Homologues of the Supracochlear Lamina: a Contribution to our Knowledge of Mammalian Ancestry

In cetaceans, each otic capsule is bound anteriorly to the remainder of the endocranium by an aliform structure called the supracochlear lamina. This lamina has been established here as the homologue of the sphenocochlear commissure of other mammals. Most researchers believe that these two structures arose within mammals. However, a comparative study involving data from both extant and extinct craniates suggests that the supracochlear lamina and the sphenocochlear commissure have a long premammalian history. The conclusion is that the lower of the two pharyngeal segments at the upper end of the mandibular branchial arch first became incorporated in the endocranium, constituting the cartilago trabecularis in the embryos of jawed craniates. The distal, or posterior, extremity of the trabecular cartilage projected outwardly to form the basitrabecular process. This process, which when ossified is called the processus basipterygoideus, functioned as a jaw support. Later, one more jaw support, termed the basivincular, evolved immediately in front of the basipterygoid process. Both these supports for the upper jaw existed in the piscine forerunners of the tetrapods. Subsequently, in the lineages leading to mammals, the basivincular jaw support became the processus alaris to which is attached an upper jaw endoskeletal remnant, called the ala temporalis. The basipterygoid jaw support, however, vanished as a consequence of the evolution of an exoskeletal joint system for the jaws of mammals. Yet the basipterygoid process persisted and as the sphenocochlear commissure or the supracochlear lamina assumed the new function of supporting the cochlear part of the auditory capsule.     

Yet Another Interpretation of the Coelacanthiform Basicranial Muscle and its Innervation

Abstract A compilation of newly published information on the innervation of the basicranial muscle in the living tufttail Latimeria chalumnae and data obtained from other craniates, extant as well as extinct, suggest that the coelacanthiform basicranial musculature and the nerve supply which pertains to it are trimetameric in character rather than monometameric, as usually reported. This result supports the available data on the basic composition of the head of craniate animals and gives no support to a recently suggested homology between the tufttail basicranial muscles and the tetrapod retractor bulbi musculature.     

Differential response of cycling and noncycling cells to inducers of DNA synthesis and mitosis

The objective of this study was to determine whether cells in G(0) phase are functionally distinct from those in G(1) with regard to their ability to respond to the inducers of DNA synthesis and to retard the cell cycle traverse of the G(2) component after fusion. Synchronized populations of HeLa cells in G(1) and human diploid fibroblasts in G(1) and G(0) phases were separately fused using UV-inactivated Sendai virus with HeLa cells prelabeled with [(3)H]ThdR and synchronized in S or G(2) phases. The kinetics of initiation of DNA synthesis in the nuclei of G(0) and G(1) cells residing in G(0)/S and G(1)/S dikaryons, respectively, were studied as a function of time after fusion. In the G(0)/G(2) and G(1)/G(2) fusions, the rate of entry into mitosis of the heterophasic binucleate cells was monitored in the presence of Colcemid. The effects of protein synthesis inhibition in the G(1) cells, and the UV irradiation of G(0) cells before fusion, on the rate of entry of the G(2) component into mitosis were also studied. The results of this study indicate that DNA synthesis can be induced in G(0)nuclei after fusion between G(0)- and S-phase cells, but G(0) nuclei are much slower than G(1) nuclei in responding to the inducers of DNA synthesis because the chromatin of G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells differ from G(1) cells with regard to their effects on the cell cycle progression of the G(2) nucleus into mitosis. This difference between G(0) and G(1) cells appears to depend on certain factors, probably nonhistone proteins, present in G(1) cells but absent in G(0) cells. These factors can be induced in G(0) cells by UV irradiation and inhibited in G(1) cells by cycloheximide treatment.     

Exercise training in childhood-onset systemic lupus erythematosus: a controlled randomized trial

Introduction

Exercise training has emerged as a promising therapeutic strategy to counteract physical dysfunction in adult systemic lupus erythematosus. However, no longitudinal studies have evaluated the effects of an exercise training program in childhood-onset systemic lupus erythematosus (C-SLE) patients. The objective was to evaluate the safety and the efficacy of a supervised aerobic training program in improving the cardiorespiratory capacity in C-SLE patients.

Methods

Nineteen physically inactive C-SLE patients were randomly assigned into two groups: trained (TR, n = 10, supervised moderate-intensity aerobic exercise program) and non-trained (NT, n = 9). Gender-, body mass index (BMI)- and age-matched healthy children were recruited as controls (C, n = 10) for baseline (PRE) measurements only. C-SLE patients were assessed at PRE and after 12 weeks of training (POST). Main measurements included exercise tolerance and cardiorespiratory measurements in response to a maximal exercise (that is, peak VO₂, chronotropic reserve (CR), and the heart rate recovery (ΔHRR) (that is, the difference between HR at peak exercise and at both the first (ΔHRR1) and second (ΔHRR2) minutes of recovery after exercise).

Results

The C-SLE NT patients did not present changes in any of the cardiorespiratory parameters at POST (P > 0.05). In contrast, the exercise training program was effective in promoting significant increases in time-to-exhaustion (P = 0.01; ES = 1.07), peak speed (P = 0.01; ES = 1.08), peak VO₂ (P = 0.04; ES = 0.86), CR (P = 0.06; ES = 0.83), and in ΔHRR1 and ΔHRR2 (P = 0.003; ES = 1.29 and P = 0.0008; ES = 1.36, respectively) in the C-SLE TR when compared with the NT group. Moreover, cardiorespiratory parameters were comparable between C-SLE TR patients and C subjects after the exercise training intervention, as evidenced by the ANOVA analysis (P > 0.05, TR vs. C). SLEDAI-2K scores remained stable throughout the study.

Conclusion

A 3-month aerobic exercise training was safe and capable of ameliorating the cardiorespiratory capacity and the autonomic function in C-SLE patients.

Trial registration

NCT01515163.     

The Fates of Spiracular Allostoses in Mammals

The human temporal bone includes an upper and a lower allostotic component, which are referred to, respectively, as the pars squamosa and pars tympanica in the adult and as the os squamosum and os tympanicum in the fetus. The consensus is that the former is descended from a cheek bone and the latter from a jaw bone in piscine osleolepipods. However, no corroborating evidence supports this view. It is concluded here that both these allostotic components of the human temporal bone derive from spiracular allostoses, except for the zygomatic process of the pars squamosa, this being a cheek allostosis that has been secondarily united with the squama. This is the first recognition of erstwhile spiracular allostoses in tetrapods. These conclusions challenge the widely accepted Reichert-Gaupp theory as well as the oft-alleged monophyletic status of the mammals and their derivation from therapsid reptiles.     

Survival Rate and Enzyme Activities ofLactobacillus acidophilusFollowing Frozen Storage

The ability of two strains of Lactobacillus acidophilus, CRL 640 and CRL 800, to survive and retain their biological activities under frozen storage was determined. Freezing and thawing, as well as frozen storage, damaged the cell membrane, rendering the microorganisms sensitive to sodium chloride and bile salts. Both lactic acid production and proteolytic activity were depressed after 21 days at -20 degreesC, whereas beta-galactosidase activity per cell unit was increased. Cell injury was partially overcome after repair in a salt-rich medium. Copyright 1998 Academic Press.     

The Question of a Presupracleithrum in Brachiopterygian Fishes

The presupracleithrum is an exoskeletal pectoral bone that occurs in Paleozoic and Mesozoic actinopterygian fishes. It has been equated more than once with an opercular element in brachiopterygian fishes. In recent cladistic analyses, this alleged homology is used to assign brachiopterygians to actinopterygians. However, a comparison of brachiopterygian and actinopterygian crania shows clearly that the former lack a presupracleithrum.