Further observations on the osteometric discriminant function. The human clavicle

Linear discriminant functions of three terms have been calculated from the clavicular measurements published by F. G. Parsons. They have been applied to a known series of bones to assess their efficiency in sex-determination.     

Observations on the fluorescence and function of spiders' eyes

Preliminary observations on spiders' eyes showed that certain eyes fluoresce in ultraviolet light and others do not. The response of these eyes to ultraviolet and visible light has been investigated to discover the relationship, if any, of eye fluorescence with eye function.
In the first part of this paper it is shown that of eight spiders from families with widely differing habits, vision and behaviour, five species reacted to light fluctuations and to differences in brightness of the primary colours blue, green and red. Three species did not respond to lightand only two, S. scenicus and E. falcata , indicated a preference for blue light. It was also found that the visual sensitivity of S. secenicus extended into the ultraviolet. The second part of the paper gives the results of examination in ultraviolet light of the eyes of 40 species from 11 families. Spiders with poor sight and a preference for shade generally showed a strong fluorescence of all eyes. The anterior median and lateral eyes of those species with good sight fluoresced only weakly or not at all, whereas the posterior median and lateral eyes ofthese spiders fluoresced brightly.
Freshly cut frozen sections of the eyes of two selected species, S. scenicus with good sight and C. similis with poor sight, were examined with the fluorescence, phase and polarizing microscopes. The localization of the fluorescence in these eyes is described and a fluorescent substance, common to all the spiders, was found in the lens of the eyes of most species examined.Additional information on the structure of the cornea and lens was also revealed by phase and polarized light microscopy.
The results suggest that spiders' eyes respond to light in different ways and the fluorescent substance present in the lens of the eyes is related to eye function.     

Chronic osteomyelitis of the clavicle

Osteomyelitis of the clavicle is an uncommon disease, but it should be considered in patients who present with pain, cellulitis, or drainage in the sternoclavicular area following head and neck surgery, irradiation, subclavian vein catheterization, or immunosuppression. An idiopathic presentation is possible. In contrast to primary osteomyelitis of the clavicle, which is occasionally seen in children, secondary osteomyelitis is quite rare. It is often mistaken for a fracture or a possible neoplasm on plain x-rays. Tomograms and CT scanning are confirmatory, and in early cases, technetium-99m bone scanning can be helpful. Treatment must include early, aggressive surgical debridement of all affected tissues, followed by wound coverage with a well-vascularized flap and perioperative antibiotics.     

Influence of geometrical personalization on the simulation of clavicle fractures

Finite element body models enable the evaluation of car occupant protection. In general, these models represent average males and inter-individual geometry variability is not taken into account. As the most frequent shoulder injury during car lateral accidents is a clavicle fracture, the purpose of this study is to investigate whether clavicle geometry has an influence on bone response until failure, and whether geometrical personalization of clavicle models is required. Eighteen clavicles from 9 subjects (5 males and 4 females, mean age: 76 +/- 12 years) were harvested. Six clavicles were scanned, enabling the development of subject-specific models and the quantification of geometrical features defining shape and cortical thickness. Bone mineral densities (BMD) were measured through double X-ray absorptiometry. Then, the general clavicle responses to dynamic compression until failure were studied. Simulations of the compression tests were carried out with the subject-specific models to assess the sensitivity of force-deflection clavicle responses to geometrical features. Clavicle fractures occurred at an average velocity of 1.41 +/- 0.4 ms(-1), with a fracture force of 1.48 +/- 0.46 kN and a deflection of 5.4 +/- 1.1 mm. A significant difference was found between male and female clavicle force values at rupture although their BMDs were not significantly different. Simulations with subject-specific models led to the conclusion that cortical bone thickness and bone shape have large effects on bone responses until failure and on fracture location. This study highlights the need for a geometrical personalization of clavicle models in order to take into account both gender discrepancies concerning clavicle shape and aging effects affecting cortical thickness.     

Observations on the function of a slowly-adapting mechanoreceptor associated with filoplumes in the feathered skin of pigeons

Summary The response properties of a slowlyadapting mechanoreceptor located at the base of filoplumes in the feathered skin of the pigeon have been studied electrophysiologically. Both a strong dynamic component and an irregular firing rate and a cold-sensitivity show considerable similarity to the type SA I receptor in the mammalian skin whose morphological basis is a Merkel cell receptor. The functional characteristics have been studied with regard to excitation under natural conditions. The filoplumes are usually associated with contour feathers and excitation occurs only during lateral displacement of contour feather or movement of filoplume. This points to a role of the SA receptor in sensing disorders of the plumage. This is supported by the finding that one afferent fiber innervates only one feather which means a high spacial resolution. Furthermore a possible role in bird flight is discussed.Abbreviation SA slowly-adapting     

The development of the clavicle in man

The development of the human clavicle was studied in 50 to 60 d old human embryos. Our findings are summarized as follows: The whole clavicle develops from a cartilaginous anlage. In the middle part of the clavicle, an osseus cuff develops very early by the ossification in the perichondrium. In the lumen of this cuff, a cartilaginous cork persists which is resorbed and replaced by bone and marrow later than in other bones. It is possible that cartilaginous nests may persist in the middle part of the clavicle. In both extremities of the clavicle, the normal enchondral ossification exists as it is described in other anlages. It is difficult to explicate the syndrome of the cleido-facial and cleido-cranial dysostoses only as disturbances of the endesmal ossification.     

Observations on migration inhibition of sensitized peritoneal exudate cells as a function of time

The movement of sensitized guinea pig macrophages from peritoneal exudate on a nutrient agar base is inhibited by specific antigen for a period up to 48 hr. There-after, the macrophages gradually return to normal motility, although vacuoles persist in the cytoplasm and the pseudopodia tend to be elongated. Prolonged exposure of MIF to 37 °C tends not to reduce its activity significantly.     

Observations on the Structure of Spores

The differential light scattering characteristics of single spores of Bacillus sphaericus and Clostridium filamentosum were measured and recorded for several hundred different spores using an argon-ion laser source (λ=514.5 nm) and a single-particle light-scattering photometer. Typical recorded light-scattering patterns were interpreted analytically by adjusting the parameters of a spherically symmetrical model to the data using a least squares fitting procedure. The size fluctuations of the cores were very small which suggests that their structure may well be identical for different spores of the same species. The greater variability of the spore surface thickness seems to indicate that these components are loosely defined during sporulation and will certainly vary with growth conditions. Based on the observed lack of free water within the cores, a hypothesis is presented that dipicolinic acid (DPA) acts as a filler material in the core to prevent free water penetration.