Fracture propagation in the human cranium: a re-testing of popular theories.

Bone trauma interpretation is an important area of forensic anthropology. Notwithstanding the recent realization of the validity of fracture pattern interpretation, knowledge of trauma is largely based on case studies and older experimental work. Gurdjian and coauthors conducted a number of studies on blunt force fracture propagation that are still used today. Fracture propagation was noted to initiate in an area other than the point of impact, then radiate back toward it. Gurdjian's results are often used to suggest that the point of impact is at a location other than the fracture epicenter. This study is an examination and retesting of Gurdjian's theories of fracture propagation using current biomechanics research and technology. Specifically, the relationship of impact site and fracture patterning was tested using cadaver heads. The results demonstrate that fractures radiate from the point of impact, contrary to the theories of Gurdjian.

[Chronic subdural hematoma - assessment and management]. / Chronisches Subduralhämatom - Beurteilung und Management.

Subdural hematomas (SDH) are associated with an increased morbidity and mortality and generally occur as chronic SDH among older patients. The most frequent signs and symptoms - like headache, alteration of consciousness, gait impairment and hemiparesis - are also prevalent among other diseases, which has to be taken into account in the differential diagnosis. In the case of symptomatic patients with focal neurological deficits, a surgical intervention should be considered, whereas in case of asymptomatic patients or patients with only slight headaches, also a conservative treatment with a clinical and radiological follow-up might be a possibility. Also after surgical intervention, the recurrence rate is between 5 and 33%. Therefore, all patients with chronic SDH depict, irrespective of the indication for an oral anticoagulation, a challenge for the treating physicians.

Nuclear stopping from 0.09A to 1.93A GeV and its correlation to flow.

We present a complete systematics (excitation functions and system-size dependences) of global stopping and side flow for heavy ion reactions in the energy range between 0.09A and 1.93A GeV. For the heaviest system, Au+Au, we observe a plateau of maximal stopping extending from about 0.2A to 0.8A GeV with a fast drop on both sides. The degree of stopping, which is shown to remain significantly below the expectations of a full stopping scenario, is found to be highly correlated to the amount of side flow.

Azimuthal dependence of collective expansion for symmetric heavy-ion collisions.

Detailed studies of the azimuthal dependence of the mean fragment and flow energies in the Au+Au and Xe+CsI systems are reported as a function of incident energy and centrality. Comparisons between data and model calculations show that the flow energy values along different azimuthal directions could be viewed as snapshots of the fireball expansion with different exposure times. For the same number of participating nucleons more transversally elongated participant shapes from the heavier system produce less collective transverse energy. Good agreement with Boltzmann-Uehling-Uhlenbeck calculations is obtained for a soft nuclear equation of state.

Hand/wrist disorders among sign language communicators.

The study assessed the frequency of self-reported hand/wrist problems among sign language communicators, including interpreters, deaf or hard-of-hearing individuals, and educators. Comparisons were also made between sign language communicators and the general population regarding the frequency of medically diagnosed carpal tunnel syndrome. A survey was mailed to attendees of a national conference that focused on the quality of postsecondary educational opportunities for students with hearing deficits. Fifty-nine percent of 184 respondents reported experiencing hand/wrist problems. Twenty-six percent reported experiencing hand/wrist problems severe enough to limit the ability to work, and 18% reported a medical diagnosis of wrist tendinitis, carpal tunnel syndrome, or both. The frequency of self-reported, medically diagnosed carpal tunnel syndrome for the surveyed sign language communicators was five times the rate experienced by working Americans between ages 18 and 60 years (Tanaka, Wild, Seigman, Halperin, Behrens, & Putz-Anderson, 1995). The study supports increased emphasis on and availability of hand/wrist disorder risk reduction programs for sign language users.

A Xenopus protein related to hnRNP I has a role in cytoplasmic RNA localization.

Cytoplasmic localization of mRNA molecules is a powerful mechanism for generating cell polarity. In vertebrates, one paradigm is localization of Vg1 RNA within the Xenopus oocyte, a process directed by recognition of a localization element within the Vg1 3' UTR. We show that specific base changes within the localization element abolish both localization in vivo and binding in vitro by a single protein, VgRBP60. VgRBP60 is homologous to a human hnRNP protein, hnRNP I, and combined immunolocalization and in situ hybridization demonstrate striking colocalization of hnRNP I and Vg1 RNA within the vegetal cytoplasm of the Xenopus oocyte. These results implicate a novel role in cytoplasmic RNA transport for this family of nuclear RNA-binding proteins.

Synthesis, pharmacological characterization, and molecular modeling of heterobicyclic amino acids related to (+)-2-aminobicyclo[3.1.0] hexane-2,6-dicarboxylic acid (LY354740): identification of two new potent, selective, and systemically active agonists for group II metabotropic glutamate receptors.

As part of our ongoing research program aimed at the identification of highly potent, selective, and systemically active agonists for group II metabotropic glutamate (mGlu) receptors, we have prepared novel heterobicyclic amino acids (-)-2-oxa-4-aminobicyclo[3.1. 0]hexane-4,6-dicarboxylate (LY379268, (-)-9) and (-)-2-thia-4-aminobicyclo[3.1.0]hexane-4,6-dicarboxylate (LY389795, (-)-10). Compounds (-)-9 and (-)-10 are structurally related to our previously described nanomolar potency group II mGlu receptor agonist, (+)-2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylate monohydrate (LY354740 monohydrate, 5), with the C4-methylene unit of 5 being replaced with either an oxygen atom (as in (-)-9) or a sulfur atom (as in (-)-10). Compounds (-)-9 and (-)-10 potently and stereospecifically displaced specific binding of the mGlu2/3 receptor antagonist ([3H]LY341495) in rat cerebral cortical homogenates, displaying IC50 values of 15 +/- 4 and 8.4 +/- 0.8 nM, respectively, while having no effect up to 100 000 nM on radioligand binding to the glutamate recognition site on NMDA, AMPA, or kainate receptors. Compounds (-)-9 and (-)-10 also potently displaced [3H]LY341495 binding from membranes expressing recombinant human group II mGlu receptor subtypes: (-)-9, Ki = 14.1 +/- 1.4 nM at mGlu2 and 5.8 +/- 0.64 nM at mGlu3; (-)-10, Ki = 40.6 +/- 3.7 nM at mGlu2 and 4.7 +/- 1.2 nM at mGlu3. Evaluation of the functional effects of (-)-9 and (-)-10 on second-messenger responses in nonneuronal cells expressing human mGlu receptor subtypes demonstrated each to be a highly potent agonist for group II mGlu receptors: (-)-9, EC50 = 2.69 +/- 0.26 nM at mGlu2 and 4.58 +/- 0.04 nM at mGlu3; (-)-10, EC50 = 3.91 +/- 0.81 nM at mGlu2 and 7.63 +/- 2. 08 nM at mGlu3. In contrast, neither compound (up to 10 000 nM) displayed either agonist or antagonist activity in cells expressing recombinant human mGlu1a, mGlu5a, mGlu4a, or mGlu7a receptors. The agonist effects of (-)-9 and (-)-10 at group II mGlu receptors were not totally specific, however, as mGlu6 agonist activity was observed at high nanomolar concentrations for (-)-9 (EC50 = 401 +/- 46 nM) and at micromolar concentrations (EC50 = 2 430 +/- 600 nM) for (-)-10; furthermore, each activated mGlu8 receptors at micromolar concentrations (EC50 = 1 690 +/- 130 and 7 340 +/- 2 720 nM, respectively). Intraperitoneal administration of either (-)-9 or (-)-10 in the mouse resulted in a dose-related blockade of limbic seizure activity produced by the nonselective group I/group II mGluR agonist (1S,3R)-ACPD ((-)-9 ED50 = 19 mg/kg, (-)-10 ED50 = 14 mg/kg), indicating that these molecules effectively cross the blood-brain barrier following systemic administration and suppress group I mGluR-mediated limbic excitation. Thus, heterobicyclic amino acids (-)-9 and (-)-10 are novel pharmacological tools useful for exploring the functions of mGlu receptors in vitro and in vivo.

An experimental study of airbag impact to the orbit using an instrumented Hybrid III headform.

This paper provides the results from an experimental study intended to assess airbag impact to the orbit. Twenty-seven airbags were deployed onto an instrumented Hybrid III headform. Seven different types of airbags were used that included tethered and nontethered, light to heavy nylon weaves, and different coating types. The airbags were deployed via a pneumatic deployment system. Seven individual force transducers, each having a 2.25 cm2 contact area, were placed on the right orbital region to evaluate the force patterns. The midpoint of the two ocular regions of the headform was positioned 12.5 cm above and 15.0 cm away from the center of the airbag, a position determined from previous airbag deployments to yield the highest leading edge velocity. The average maximum force per sensor ranged from 15.4 N to 63.6 N, and peak pressure ranged from 68 kPa to 282 kPa. The upper center of the orbit presented the highest values while the center of the orbit recorded the lowest values, a comparison that was proven to be statistically significant. For this configuration, the maximum force on the ocular region was found to be independent of the presence of a tether or the maximum internal airbag pressure.

Airbag-induced eye injuries: experiments with in situ cadaver eyes.

In an attempt to investigate eye injuries from airbags, a set of experiments was performed that involved the deployment of several types of airbags onto thirteen unembalmed, previously frozen cadaver heads. The airbags differed in the material, coating, presence of a tether, and folding pattern, and were deployed via a pneumatic deployment system. The eyes were impacted in situ after being repressureized with saline injected through a 30-gauge needle. Injury determination was achieved by ophthalmic ultrasound imaging, staining with fluorescein dye, and dissection. All twenty-six eyes revealed detached retinas, as shown by the ultrasound, before impact as a result of decaying tissue and the freezing process. High speed video and film were used to capture the events. The impact velocities of the airbags were recorded from the digitized film at the first contact location with the eye and ranged from 30 m/s to 66 m/s. Eyeglasses were placed on four of the specimens, and the presence of eyeglasses seemed to provide protection to the eye because of the lack of contact between the airbag and ocular region. Minimal ocular damage was recorded for all experiments.

Production of spiral fractures in human cadaver long bones by use of a simple torsion machine.

A simple machine was developed so that long bones could be torqued to failure in order to estimate applied moment and study the resulting spiral fracture pattern. Detailed study of the fragments enabled the postulation of an orderly manner of fracture propagation. Twenty-seven embalmed human cadaver femurs were studied. The machine held one end of the bone in a fixed vise and the other in a rotating vise. Spring scales were used to apply force to a bar connected to the rotating vise which allowed for a crude estimation of torsional moment. Male femurs (72.8 yrs old sigma = 11.4) fractured at a mean torque of 106.7 N-m (sigma = 23.8), while female femurs (78.0 yrs old sigma = 6.7) failed at a mean torque of 96.7 N-m (sigma = 39.4). There were no statistically significant differences between the ages (p = 0.20) or the torsional moments at fracture (p = 0.41) for the male and female femurs. Given the similarities in this study population, an eye was turned towards anthropomorphic measurements in order to determine factors that might be indicative of bone strength. Several measurements were made on the fragments especially in the midshaft region. These included six cortex thicknesses, bone depth, width and circumference. Simple statistical analyses were performed.

Fractures of experimentally traumatized embalmed versus unembalmed cadaver legs.

Intact legs from six geriatric cadavers were fractured in a self-controlled study aimed at documenting the effects of embalming on both the soft and hard tissues of cadaver specimens subjected to biomechanical impact research. Upon bequeathal, one leg was removed and frozen while the other remained with the cadaver for embalming. The embalmed legs were amputated later and pre-test radiographs were made. For testing, a rod was inserted in the upright leg such that simulated upper body mass could be applied. A 50 kg cart propelled by a pneumatic accelerator to 7.5 m/s struck the anterior leg midway between the knee and ankle. The cart was headed by an instrumented steel pipe (4.75 cm dia.) coupled to a transducer which relayed impact force data to a Hewlett Packard 3562 A signal analyzer. Testing was captured on standard VHS video (30 frames/s) and 16 mm Color High Speed Film (1,000 frames/s). Post-test analyses included radiographs and thorough dissection. Peak forces were comparable for matched pairs. The unembalmed legs showed greater soft tissue damage (muscle and skin) but generally less bone fragmentation than their embalmed counterparts. Neurovascular components were virtually unharmed in most legs.

Airbag-induced eye injuries: a report of 25 cases.

OBJECTIVE: To acquire a better understanding of airbag-induced eye injuries, 25 cases are reviewed and an attempt is made to identify the causal mechanisms associated with each injury. DESIGN AND METHODS: The National Highway Traffic Safety Administration's National Accident Sampling System for the years 1984-1994 was accessed to identify automobile accidents that included airbag deployment and injury to the ocular region. The search provided 25 such cases with detailed studies of the accident scene and medical records of the injuries. The cases were comprehensively reviewed to determine the casual mechanisms associated with each group of injuries. RESULTS: The study determined that the injuries range from mild corneal abrasions to retinal detachment. Causation for each injury was determined and is detailed. The injuries were grouped according to location within the ocular region, and the distribution is shown. CONCLUSIONS: Most of the injuries were induced by impact with the fully deployed airbag, but the more severe ocular trauma resulted from the actively deploying airbag striking the occupant. Thus, ocular trauma from airbags can occur in very minor impacts. Additionally, the left eye seemed more vulnerable to injury than the right. Nontethered airbags have greater inflation distances that tend to increase the probability of injury. External parameters that may also increase the severity of eye injury include an unfastened seat belt, sitting too close to the steering wheel, or wearing glasses.

Aromatase inhibition by 5-substituted pyrimidines and dihydropyrimidines.

The inhibition of estrogen biosynthesis has been suggested to be an effective treatment of hormone-dependent diseases, particularly breast cancer. Several series of 5-substituted pyrimidine derivatives have been synthesized and tested for their ability to inhibit the enzyme aromatase (estrogen synthetase). Compounds were evaluated in an in vitro assay that measured the inhibition of rat ovarian microsomal aromatase activity. Greatest inhibitory activity was achieved in the cases of diarylpyrimidinemethanols and diarylpyrimidinyl methanes which were substituted in the 4- and 4'-positions with electron-withdrawing substituents, particularly Cl.