Hammer blows to the head.

Hammer blows cause serious, often fatal injuries, especially when massive blunt violence is targeted at the head region. The evaluation of the injury potential depends not only on the body region hit, but also on the characteristics of the hammer as a weapon and on the physical characteristics of the attacker. This study aimed at elucidating the dependency between the physical constitution of a perpetrator and the intensity of hammer blows, thus to verify or refute this seemingly obvious interrelation sometimes expressed in the saying that a "strong hand strikes harder". For this purpose, 113 volunteers of different ages and sexes took part in different experimental settings. While, as expected, clear differences between male and female were detectable in the striking power of single and multiple strokes, there were no age or sex differences with regard to the maximum number of strokes per time unit. Strength differences in slamming with a hammer between men and women exceeded expectations in this study. Using the fracture forces as described by Sharkey et al. in an exemplary manner, one can expect a fracture of the skull in 9 out of 10 cases with a 300 g hammer by men for intensively executed single strokes, whereas this was only the case for approx. 2/10 women in this study. The maximum circumference of the upper arm and the width of the shoulder girdle correlate significantly with the achievable impact forces of individual hammer blows in both sexes. A simple measurement of the hand force with a manometer using the regression formula y [kN] = 0.144 × manual grip force -1.08 can be used as a rough estimation parameter for the theoretically achievable impact force. If one strikes repeatedly with the same hammer for 1 min, the magnitude of a single strike decreases continuously from 4.5 kN to 2.6 kN on average. If a 1500 g hammer is used instead of a 300 g hammer, one does not get the fivefold impact force you might expect at first sight, but only on the order of twice the impact force, about 14 kN on average. The results prove the importance of physical experiments, whose results can help to better interpret the magnitude and effects of hammer blows as a form of potentially life-threatening violence.

[Obstructive sleep apnoea syndrome as the cause of atypical depression]. / Obstruktives Schlaf-Apnoe-Syndrom als Ursache einer atypischen Depression.

Sleep apnoea is a common disorder presenting with somatic comorbidities and psychiatric symptoms. This case report describes a 43-year-old man with an organic depressive disorder due to obstructive sleep apnoea. Initially, an atypical depressive episode or schizophrenic residual syndrome had been considered likely diagnoses; subsequent polysomnography results, however, suggested obstructive sleep apnoea instead. Upon nasal continuous positive airway pressure (nCPAP), the respiratory distress symptoms improved. The case report highlights the association between sleep disturbances and depressive symptoms. In patients presenting with symptoms of atypical depression and excess body weight sleep apnoea should be considered.

Are one or two dangerous? Lidocaine and topical anesthetic exposures in children.

Topical anesthetics are found in a variety of prescription and non-prescription preparations, from teething gels to hemorrhoid creams. In 2003, there were 8576 exposures to local/topical anesthetics reported to the American Association of Poison Control Centers, with 67% of cases in the age group younger than 6 years old. This report reviews the available literature involving topical anesthetic exposures in children younger than 6 years old, including the National Library of Medicine's Pub Med database (limited to English language) and data from POISINDEX. Additionally, we reviewed the American Association of Poison Control Centers' annual reports from 1983 to 2003. There were 7 deaths in this age range from topical anesthetics. Although the number of deaths is low, the fact that there have been deaths reveals the serious nature of the toxicity that can result from these readily available non-prescription analgesics. Toxicity may result from topical absorption, ingestion, or aspiration. Additionally, toxicity can result from unintentional as well as therapeutic mishaps. Although the number of cases is limited, these medications can be toxic at low doses-which, in children younger than 6 years of age, may amount to as little as a teaspoon.

Cytotoxic potency of trialkyltins to C6 glioma cells in vitro: impact of exposure conditions.

Because of a possible role of astrocytes in trialkyltin-induced neurotoxicity in vivo various studies have been performed using cultures of astrocytes or glioma cells in vitro. With respect to cytotoxic potencies of trialkyltins these studies gave rather divergent results. Therefore the aim of the present study was to clarify whether variations of experimental conditions could be responsible for the differences of the cytotoxic activities of trimethyltin (TMT), triethyltin (TET) and tributyltin (TBT). Experiments were performed with rat C6 glioma cells. Toxicity was determined by measuring the reduction of the cell protein content. Cultures of proliferating and growth-arrested cells did not differ in their sensitivity. Exposure duration (1-72 h) had a strong but differing influence on the cytotoxic potency of the trialkyltins. After short exposure times the potencies differed largely (TMT < TET < TBT), whereas they became more and more similar with increasing exposure duration. The potency-time relationships for TMT and TET could be described by the equation: EC50 = k x t(-n), while for TBT an incipient value (EC50, infinity) had to be included: EC50 = EC50, infinity + k x t(-n). Addition of serum albumin to the culture medium decreased the cytotoxic potency of the trialkyltins. However, the impact of protein binding on their bioavailability was relatively low. The cytotoxic potency of the alkyltins was not dependent on the concentration of C6 cells. Taken together, neither differences in exposure conditions nor in the proliferative status of the cells are sufficient to account for the discrepancies in published results for trialkyltin cytotoxicity to astrocytes. Instead they may--at least partially--be explained by differing sensitivities of the endpoints used. Furthermore, C6 glioma cells respond considerably more sensitively to trialkytins than primary astrocytes, which questions their applicability as models for astrocyte toxicity.

Factors influencing nominal effective concentrations of chemical compounds in vitro: medium protein concentration.

Quantitative data used to characterise biological activities of chemicals in vitro (e. g. EC50 values) are generally based on nominal concentrations and thus depend on factors influencing the availability of a compound. In this study, the impact of protein binding on the availability of chemicals in vitro is theoretically investigated and experimentally examined using a bovine sperm cell assay to measure the cytotoxic potency of selected compounds at different medium protein concentrations. In agreement with theoretical considerations, linear correlations between EC50 values and medium albumin concentrations were determined with 2,4-dichlorophenol, pentachlorophenol, p,p'-DDT and mercuric chloride. Ratios of EC50 values measured in the presence and absence of 4% (w/v) albumin varied between 500 (hexachlorophene), 258 (pentachlorophenol) and almost 1 (potassium cyanide, dextropropoxyphene). Calculated molar ratios of substance bound to albumin ranged from 0.05 (arsenic trioxide) and 0.1 (potassium cyanide) to 2.5 and 4.7 moles/mole for malathion and xylene, respectively. The fractions bound at 4% albumin varied between 11 and 15% for dextropropoxyphene and potassium cyanide, respectively, and more than 99% for hexachlorophene, pentachlorophenol and mercuric chloride. The results clearly demonstrate that the differing impact of protein binding on the bioavailability of chemicals considerably influences their nominal and relative potencies in the presence of albumin.

Toxicity of organotin compounds in primary cultures of rat cortical astrocytes.

The neurotoxic organotin compounds trimethyl (TMT) and triethyltin (TET) are known to induce astrogliosis in vivo, which is indicated by an increased synthesis of glial fibrillary acidic protein (GFAP) in astrocytes. In contrast, tributyltin (TBT) does not induce astrogliosis. The aim of this study was to investigate whether trialkyltin derivatives can induce an increased GFAP synthesis in astrocyte cultures in the absence of neurons and whether differences between the action of TMT, TET, and TBT can be detected. Primary cultures of rat cortical astrocytes from 2-day-old rats were grown in 96-well plates until confluency and then exposed to various concentrations of TMT, TET, and TBT for 40 h. Effects on basal cell functions were measured by colorimetric determination of cell protein contents and by assessment of viability by means of the MTT assay. An indirect sandwich ELISA for 96-well plates was used for quantitative measurements of the GFAP content of the cells. All three compounds induced a concentration-dependent cytotoxicity indicated by parallel decreases of protein contents and MTT reduction. Half-maximum cytotoxic concentrations were 3 micromol/L (TBT), 30 micromol/L (TET), and 800 micromol/L (TMT). Cellular GFAP contents were reduced in parallel to cytotoxic action but no increase in GFAP expression at subcytotoxic concentrations could be observed. Thus, the astrocytes were not able to respond to TMT or TET exposure by an increased synthesis of GFAP in the absence of neuronal signals.

Factors influencing nominal effective concentrations of chemical compounds in vitro: cell concentration.

In vitro potency data (e.g. EC(50) values), used to characterise the biological activity of chemicals, are generally based on nominal effective concentrations and thus depend on any factor influencing the availability of a compound. In this study the significance of cell binding for the availability of chemicals in vitro is (i) theoretically investigated by means of a simple equilibrium distribution model and (ii) experimentally examined using a bull sperm assay to measure the cytotoxic potency of selected compounds at different cell concentrations. Compounds were selected either to cover a wide range of hydrophobicity (log K(ow)=2.52-5.69) or to represent modes of cell binding other than partitioning into cellular lipids. With the exception of xylene, the EC(50) values increased with increasing cell concentration. The ratios of EC(50) values determined at about 120 x 10(6) and 15 x 10(6) cells/ml were: pentachlorophenol. 1.2, 1-nitronaphthalene: 1.9, thioridazine: 2.7, dieldrin: 4.1, hexachlorophene: 4.1, digitonin: 5.1, methylmercury chloride: 7.9, antimycin A: 10.1 and p,p'-dichlorodiphenyl dichloroethylene (p,p'-DDE): >19.1. The influence of partitioning into cell lipids was rather well predicted by the equilibrium distribution model, except for p,p'-DDE. The results show that cell binding can significantly affect the availability of compounds in vitro and thus toxic potencies and toxic equivalency factors.

Evidence for induction of a phosphate appetite in juvenile rats.

This study examined whether dietary phosphate (Pi) restriction stimulates an appetite for Pi in the juvenile rat, which normally has a high metabolic Pi demand for growth. Juvenile Wistar rats were placed in individual cages with unrestricted access to tap water and a low (LPD, 0.02% Pi) or normal Pi diet (NPD, 0.6% Pi) for 7 days. On day 8, both groups of rats were given unlimited access to a solution of 0.3 M potassium phosphate water (PiH2O) for 8 additional days. Rats fed LPD consumed 70-100% more PiH2O then those rats fed NPD (P < 0.001). The increase in PiH2O intake resulted in a marked rise in the growth rate of rats fed LPD during days 8-15. A similar Pi intake was inducible after only 2 days of LPD and was associated with significant reductions in both plasma and cerebrospinal fluid (CSF) Pi levels; these levels remained low throughout Pi restriction, despite a significant PiH2O intake. Furthermore, the renal adaptation to enhance Pi reabsorption (TmPi) during Pi deprivation remained elevated despite enhanced PiH2O intake. Replenishment with a high-Pi diet rapidly quenched the PiH2O appetite and was associated with restoration of both plasma and CSF Pi levels. These findings suggest that an appetite for Pi can be induced in juvenile rats, perhaps through lowered plasma and CSF Pi levels. This behavioral response may serve as an additional mechanism to maintain an adequate supply of Pi necessary for growth and development of the animal.

Influence of protein binding and lipophilicity on the distribution of chemical compounds in in vitro systems.

Concentration-effect relationships determined in vitro depend not only on the activity of the chemical compounds or the sensitivity of the targets but also on the distribution of the compounds in the in vitro systems. In cell cultures, protein binding and lipid/water partition can be major determinants of distribution. Both are dependent on substance-specific factors, such as affinity to protein binding sites and lipophilicity, and on system-specific factors, such as protein concentration and lipid/water relationships. With this in mind, an algorithm has been developed that relates the total concentration of a compound to the free concentration in the aqueous phase. This algorithm can be used to describe theoretically the quantitative influence of the various factors relevant for distribution on concentration-response relationships. Conditions can be defined where protein binding and lipid/water partition are quantitatively important and have to be considered when comparing EC(50) values obtained in different in vitro systems. Provided that substance- and system-related parameters are known, the algorithm can be used in comparative cell toxicology to estimate equivalent effective concentrations for differently composed systems.

Cytotoxic and non-cytotoxic effects of the MEIC reference chemicals on spontaneously contracting primary cultured rat skeletal muscle cells.

This study was designed to evaluate the suitability of a multi-endpoint test system using primary cultured spontaneously contracting rat skeletal muscle cells to indicate an acute neuro- and/or cardiotoxic potential of chemicals. The concentration-dependent effects of the 50 MEIC (Multicenter Evaluation of In Vitro Cytotoxicity) reference chemicals on contractility, indicative of the functional integrity of the electrically active muscle cell membrane, were determined. Additionally, effects on two other endpoints, glucose consumption and viability, were monitored to reveal whether alterations in contractility were associated with cytotoxicity. In total, 30 of the tested compounds inhibited contractility at non-cytotoxic concentrations. The contractility-inhibiting and cytotoxic potencies differed by factors of more than 10 in the case of diazepam, phenol, propranolol, phenobarbital, mercuric chloride, thioridazine, verapamil, chloroquine, quinidine, phenytoin and atropine, of more than 100 in the case of amitriptyline, dextropropoxyphene, orphenadrine and amphetamine, and even more than 1000 for nicotine. On the basis of the available knowledge of the acute toxic effects and modes of acute toxic action of the test compounds, this characteristic response pattern is shown to be highly predictive for compounds reported to be cardio- and/or neurotoxic owing to interference with excitable membrane functions and/or neurotransmission.

Direct measurement of cascaded nonlinearity in lithium niobate channel waveguides.

We report on interferometric measurements of nonlinear phase shifts of the fundamental mode that are due to cascading in a second-harmonic-generation experiment in lithium niobate channel waveguides. With temperature tuning of the wave-vector mismatch the nonlinear phase shifts were adjustable in sign and magnitude. Varying the wave-vector matching condition along the waveguide leads to large phase shifts with low depletion and dispersion of the fundamental.

In vitro toxicity screening using cultured rat skeletal muscle cells. II. Agents affecting excitable membranes.

The screening of chemicals for their potential to interfere with excitable cell membranes should be an important element of in vitro testing for acute toxicity. The suitability for this purpose of a test system using primary cultured rat skeletal muscle cells was evaluated. The test protocol involved the determination of the concentration-dependent effects on three endpoints: (1) spontaneous contractility, (2) membrane integrity and (3) energy metabolism. The chemicals investigated were: NaCl, KCl and CaCl(2); cardiac glycosides (ouabain, digoxin); sodium channel toxins (tetrodotoxin, saxitoxin, veratridine, Anemonia sulcata toxin II, Bolocera tuediae toxin II); an acetylcholine agonist (carbachol); a calcium antagonist (D600) and three membrane-directed insecticides (deltamethrin, DDT, lindane). The response pattern of most of these substances-alteration of contractility at concentrations that neither affected the energy metabolism nor were cytolethal-characterized them as acting either on the excitable membrane or on the excitation-contraction coupling and the contractile apparatus. The results indicate that the test system is suited to assess chemical effects resulting in: (i) changes of resting membrane and threshold potentials, (ii) altered sodium channel function, (iii) opening of endplate channels, (iv) blockade of calcium channels, and (v) inhibition of Na(+)/K(+)-ATPase.

The use of cultured skeletal muscle cells in testing for acute systemic toxicity.

A test system using primary cultured, spontaneously contracting, rat skeletal muscle cells has been developed to detect chemical interactions with excitable membranes. Taking into account some basic toxicokinetic differences between the in vivo and in vitro conditions, results obtained with the first 30 MEIC reference chemicals were quantitatively compared with in vivo acute toxicity data. The results show that the muscle cell test system is suitable for use in acute toxicity assessment and, for instance, for toxicity classification of chemicals.

An in vitro toxicity testing strategy for the classification and labelling of chemicals according to their potential acute lethal potency.

An in vitro test battery is described which consists of five systems using different types of cells: (1) bovine sperm cells, (2) Balb/c 3T3 cells, (3) primary cultures of rat hepatocytes, (4) primary cultures of rat muscle cells, and (5) co-cultures of microcarrier-attached rate hepatocytes and Balb/c 3T3 cells. This combination of in vitro systems covers various aspects of cellular toxicity and permits determination of the intrinsic activity of chemicals with respect to general cytotoxicity, selective cytotoxicity and interference with selected cell-specific functions (Seibert et al., 1992). During the current phase of evaluation the different test systems are used in parallel, resulting in in vitro toxicity profiles which are the basis (a) for interpretation with respect to toxic potential, and (b) for the selection of appropriate assays for inclusion in a hierarchical approach to testing. Based on the experience with this test battery, a preliminary stepwise approach is proposed for the classification of chemicals according to their acute lethal potency. The principle steps and candidate tests are: (1) determination of cytotoxic activity (cytolethal and cytostatic)-sperm cells, 3T3 cell line; (2) determination of hepatocyte-specific cytotoxicity and of the role of bioactivation for cytotoxic activity-co-cultures of hepatocytes and 3T3 cells; and (3) determination of the potential of chemicals to interfere with electrically excitable membranes-muscle cell cultures.

Cadmium, lead, selenium, and zinc in semen of occupationally unexposed men.

Concentrations of cadmium, lead, selenium, and zinc were determined in semen and seminal plasma of 22 volunteers by atomic absorption spectrometry. Additionally conventional semen parameters and, by means of computer videomicrography, motion parameters of spermatozoa were evaluated. Concentrations of Cd, Pb, and Zn determined in semen were not significantly different from those measured in seminal plasma. However, selenium levels were significantly higher in semen (53.8 +/- 22.9 micrograms l-1) than in seminal plasma (40.4 +/- 15.5 micrograms l-1, P < 0.01). The investigated semen samples on average contained low levels of Cd (0.4 +/- 0.23 micrograms l-1) and Pb (9.8 +/- 6.5 micrograms l-1). Studies on the intra-individual variability revealed the following average coefficients of variation (%) for element concentrations: Pb (70), Cd (53), Se (27), and Zn (23); and for semen parameters: total sperm count (46), sperm concentration (37), motility (22), ejaculate volume (21), linearity (19), linear velocity (11), curvilinear velocity (10), and percentage of normally formed sperm (9). Significant positive correlations were detected between semen selenium levels and sperm concentration (r = 0.51, P < 0.05), and percentage of normally formed sperm (r = 0.46, P < 0.05), respectively. Sperm motility (r = 0.53, P < 0.02), linear (r = 0.76, P < 0.001) and curvilinear velocity (r = 0.64, P < 0.002) were significantly correlated with semen cadmium levels.

Microcarrier-attached rat hepatocytes as a xenobiotic-metabolizing system in cocultures.

A method for the primary culture of rat liver cells on collagen-coated dextran microcarriers is described. Ethoxycoumarin deethylase (EOD) activity 24 hr after inoculation was comparable for liver cells cultured on microcarriers and on collagen-coated dishes. Cells were cultured on microcarriers for up to 48 hr and retained 25% of the initial EOD-activity that was seen in freshly isolated liver cells. Microcarrier-attached hepatocytes were cocultured with BALB/c 3T3 cells to study the metabolism-mediated cytotoxicity of cyclophosphamide (CPA). In the absence of hepatocytes, growth of 3T3 cells was not affected by CPA at concentrations up to 3600 microM. In coculture with hepatocytes, cytotoxicity of CPA was expressed in a time- and concentration-dependent manner. At high concentrations, CPA slightly depressed the EOD-activity of hepatocytes. Our results indicate that cocultivation of microcarrier-attached rat liver cells with target cells represents a valuable approach to the study of the metabolism-mediated toxicity of xenobiotics in vitro.

A chemically 'defined' diluent for cryopreservation of bovine spermatozoa.

A chemically 'defined' extender for the cryopreservation of bovine spermatozoa was developed using commercially available lecithin as an additive to protect cells against freeze damage. The effectiveness of different media in preventing cryoinjury was evaluated by assessing motion activity immediately post-thaw and after 2 h incubation at 37 degrees C by means of automatic computer image analysis. The extender best suited to maintains swimming activity consisted of the zwitter ion buffer system HEPES-Tris/Citrate (HTC) supplemented with 0.9% lecithin. The effectiveness of this diluent was compared with that of an extender containing egg yolk used routinely in breeding stations. While immediately post-thaw sperm samples frozen in HTC showed a lower motion activity than those preserved in egg yolk diluent, the opposite result was obtained after 2 h incubation at 37 degrees C.

Bovine spermatozoa as an in vitro model for studies on the cytotoxicity of chemicals: effects of chlorophenols.

The suitability of ejaculated bovine spermatozoa as an in vitro model for the assessment of the cytotoxic potential of chemicals was evaluated using several endpoints: swimming activity, adenine nucleotide content, membrane integrity and oxygen consumption. A series of chlorophenols inhibited sperm motion (motility and velocity) in a concentration-dependent manner. This could be determined quantitatively and reproducibly by means of videomicrography and automatic computer image analysis. The sperm immobilizing potency increased with increasing chlorination and was positively correlated with lipophilicity. Concentrations which reduced the percentage of moving sperm to 50% of controls ranged from 43 microM for pentachlorophenol (PCP) to 1440 microM for 4-monochlorophenol (4-MCP). Determinations of adenine nucleotides and percentages of viable cells revealed qualitative differences between the action of PCP and the lower chlorinated phenols. While the latter decreased the total adenine nucleotide contents and the percentage of unstained cells in parallel to motion inhibition, no such changes occurred after exposure to immobilizing concentrations of PCP. Penta-, tetra- and trichlorinated phenols stimulated cellular respiration, indicating their uncoupling activity, at concentrations lower than those necessary for motion inhibition. The results indicate that bovine spermatozoa may become a useful in vitro model for the toxicological evaluation of chemicals providing quantitative as well as qualitative data.

[Objective estimation of the motility of deep frozen cattle sperm by videomicrography and computer image analysis]. / Objektive Beurteilung der Bewegungsaktivität von Rindertiefgefriersperma mit Hilfe von Videomikrographie und Computer-Bildanalyse.

It was examined whether computerized image analysis (system "Brunner") is suitable for the objective evaluation of the quality of deep-frozen bull sperm obtained from the routine of breeding stations. Egg yolk particles similar in size to sperm heads were classified as immotile sperm. Thus, motility was significantly underestimated with the degree of underestimation depending on the thawing solution employed. The use of two different thawing solutions, CUE and Citrat-Glucose, resulted in significantly different sperm motion characteristics immediately after thawing as well as at the end of a 2 hour incubation period at 37 degrees C. Deep-frozen semen samples from seven bulls were compared with respect to their swimming activities. The rank order of the bulls based on the values for motility and mean velocity measured two hours post-thaw corresponded with the rank order of Non-Return-Rates with respect to bulls from the same breeding station. It appears that the combination of videomicrography and computerized image analysis is well suited for the objective evaluation of frozen-thawed bull sperm if the extender is pretreated to exclude an underestimation of motility caused by egg yolk particles.