Induction of fibroblast growth factor receptor-1 mRNA and protein by platelet-derived growth factor BB

Expression levels of growth factor receptors are subject to complex regulation, which is of consequence for their signaling capacity in physiological and pathological processes. We examined the regulation of expression levels of fibroblast growth factor receptor 1 (FGFR-1) in human fibroblasts treated with a panel of growth regulatory factors. Only platelet-derived growth factor BB (PDGF-BB) treatment had a significant effect and induced FGFR-1 mRNA levels fourfold, with a peak around 8 h of stimulation. The increase in mRNA levels was followed by an increased synthesis of FGFR-1 protein, which responded to basic FGF (bFGF) stimulation with induction of kinase activity and biological signaling. Thus, murine brain endothelial cells displayed an augmented induction of plasminogen activator activity in response to bFGF, following treatment with PDGF-BB. These data suggest that PDGF-BB could support FGFR-1-mediated biological responses in processes such as angiogenesis.

Irreversible hydrocolloids for crown and bridge impressions: effect of different treatments on compatibility of irreversible hydrocolloid impression material with type IV gypsums

OBJECTIVES

The aims of this research were: 1) to determine if the compatibility between irreversible hydrocolloids (alginates) and type IV gypsums (die stones) is affected by different treatments of the impressions before pouring, and 2) to present a rating system based on Ryge's system for clinical evaluation in order to classify the quality of gypsum casts using detail reproduction and surface structure as criteria.

METHODS

Impressions were taken on a Plexiglas staircase (heights of the steps 15-82 microns) with six irreversible hydrocolloids designed for crown and bridge and ten type I and II irreversible hydrocolloids. Impressions of each brand were divided into four groups. One group was treated with 2% potassium sulfate, the second with water, the third with an alginate stabilizer, Sorbanat (Guilini Chemie), and as a control, a fourth group which was not allowed to come into contact with any liquid, i.e., the impressions were poured dry. The differently treated impressions were poured with ten type IV gypsums. The quality of all gypsum casts was then judged according to the rating system.

RESULTS

All the irreversible hydrocolloids, if correctly treated before pouring with a compatible gypsum, could reproduce details of 20 microns. Detail reproduction did not improve with the use of 2% potassium sulfate solution compared to water or if the impressions were poured "dry". In general, the alginate stabilizer produced casts with significantly better detail reproduction and surface structure.

SIGNIFICANCE

The results show that dentists and dental technicians need to know how each specific irreversible hydrocolloid should be treated and also with which type IV gypsum it is compatible. This research also indicates that an irreversible hydrocolloid impression should not come into contact with any liquid within the first 15 min.

Carbon monoxide suicide from car exhausts

STUDY OBJECTIVE

the aim of the study was to analyse the victims and circumstances in carbon monoxide suicides from car exhausts in order to find strategies for mitigation of the suicide risk.

DESIGN

necropsy, police and hospital records were scrutinized for 194 victims who committed suicide by carbon monoxide poisoning from car exhausts during a four-year period in Sweden.

SETTING AND PARTICIPANTS

the State Institutes of Forensic Medicine in Umeå and Stockholm.

RESULTS

a higher incidence (24.2/million population) was seen in the rural region than in the urban region (14.9). Males dominated (88%), most of them middle aged. Most victims committed suicide in a car outdoors. A vacuum cleaner tube connected to the compartment was most commonly used. Severe disease, mostly psychiatric, was seen in 61% of the victims. Drugs were detected in 8% of the victims under psychiatric treatment. In 37%, earlier suicide behaviour was documented. Suicide notes were found in 40%. Blood alcohol was detected in 51% of the victims and other drugs in 7%.

CONCLUSIONS

environmental changes may reduce the number of carbon monoxide suicide from car exhausts, e.g. introduction of a law requiring catalyst exhaust, of automatic idling stop, and of exhaust pipes incompatible with vacuum cleaner tubes. The importance of accurate treatment of psychiatric patients is stressed.

Brain monoaminergic and neuropeptidergic variations in human aging

The effect of age on the monoamines 5-hydroxytryptamine (5-HT), noradrenaline (NA) and dopamine (DA), their metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), 3,4-dihydroxphenylacetic acid (DOPAC), and the 5-HT precursor 5-hydroxy-L-tryptophan (5-HTP), together with the peptides neuropeptide Y (NPY), somatostatin (SOM), and corticotropin-releasing factor (CRF), was studied in frontal cortex, gyrus cinguli and hypothalamus from 23 healthy control subjects, aged 16-75 years. After correcting for postmortem interval, significant decreases in gyrus cinguli NA, NPY and CRF, and hypothalamic DA, HVA, and 5-HIAA concentrations were obtained with advancing age. The involvement of the monoaminergic system in several functional abnormalities appearing in senescence is suggested. Furthermore, evidence is given of the participation of the peptidergic systems in the aging process.

Role of alcohol in traffic crashes involving women: passenger car fatalities in northern Sweden

OBJECTIVE

Since increased alcohol consumption and increased driving among women may lead to a growing mortality due to drunken driving among women, the study analyzed gender differences among traffic fatalities.

METHOD

Traffic fatalities (597 victims, 159 women) in northern Sweden were investigated, using autopsy and police reports, for a 10-year period, 1980-1989.

RESULTS

The incidence of inebriated female driver fatalities was 0.51 per 100 million km (men, 0.66). Eighty-six percent of the female inebriated drivers (98% of men) and 68% of female sober drivers (78% of men) initiated the crash. Blood alcohol was detected in 10% of the women (men, 32%) with a mean blood alcohol concentration of 1.1 g/kg (men, 1.9 g/kg). Of the women, 13% had liver steatosis (men, 28%). The proportion of victims with liver steatosis increased with increasing blood alcohol concentration. Only one case of liver cirrhosis was found (a man). The majority of the inebriated victims were killed from May through October (women, 73%; men, 76%), and from Fridays through Sundays (women, 87%; men, 70%). Only 27% of the inebriated women crashed between 9 PM and 6 AM, compared to 62% of the men. The body location of fatal trauma was similar in men and women and was not influenced by alcohol.

CONCLUSIONS

Female traffic fatalities differ from those of men in several respects. No evidence was found for an increase in the number of women in alcohol-related traffic fatalities in Sweden over the 10-year period studied. Drunken driving and alcohol abuse in traffic is still mainly a male problem.

Bone mineral density in patients with prostatic cancer treated with orchidectomy and with estrogens

Bone mineral density (BMD) and bone mineral content (BMC) were measured in the femoral neck area, trochanteric area and Wards triangle, and in the distal radius of the left forearm before and after 1 year of endocrine treatment in 27 patients with prostatic cancer. Eleven of the patients were treated with orchidectomy and 16 with combined oral and intramuscular estrogens. The patients were free from metastases during the entire observation period. In the orchidectomized patients, BMD and BMC of the distal radius decreased significantly following treatment, whereas no changes were observed in the estrogen-treated patients. These preliminary results demonstrate that estrogens may protect bone in male subjects also and may merit further investigations on larger groups of patients.

Compartmentalization of autocrine signal transduction pathways in Sis-transformed NIH 3T3 cells

The transforming protein of simian sarcoma virus is homologous to the platelet-derived growth factor (PDGF) B-chain. Fibroblasts transformed with simian sarcoma virus constitutively produce a growth factor that stimulates the endogenous tyrosine kinase of PDGF receptors in an autocrine manner. Autophosphorylation of PDGF receptors upon ligand stimulation provides binding sites for Src homology 2 domains of intracellular signaling molecules, which thereby become activated. We have characterized the PDGF receptor-mediated signal transduction in NIH 3T3 cells transformed with a PDGF B-chain cDNA (Sis 3T3 cells) in the absence and presence of suramin, a polyanionic compound that quenches PDGF-induced mitogenicity and reverts the transformed phenotype of the Sis 3T3 cells. Our data show that in the presence of suramin the general level of tyrosine phosphorylation was decreased. Nevertheless, autophosphorylated receptors complexed with substrates persisted in the cells. Suramin had no effect on activation of phosphatidylinositol 3'-kinase or on tyrosine phosphorylation of phospholipase C-gamma and GTPase-activating protein of Ras. On the other hand, kinase activation of Src and Raf-1, phosphorylation of protein-tyrosine phosphatase 1D/Syp and Shc, and complex formation with Grb2 were greatly diminished by suramin. A possible explanation for our findings is that different PDGF receptor-coupled signaling pathways are active in different structural or functional compartments in the cell. Those pathways that are not affected by suramin might elicit distinct cellular responses, which are not sufficient for growth and transformation.

Demonstration of functionally different interactions between phospholipase C-gamma and the two types of platelet-derived growth factor receptors

Phosphorylated tyrosine residues in receptor tyrosine kinases serve as binding sites for signal transduction molecules. We have identified two autophosphorylation sites, Tyr-988 and Tyr-1018, in the platelet-derived growth factor (PDGF) alpha-receptor carboxyl-terminal tail, which are involved in binding of phospholipase C-gamma (PLC-gamma). The capacities of the Y988F and Y1018F mutant PDGF alpha-receptors, expressed in porcine aortic endothelial cells, to bind PLC-gamma are 60 and 5% of that of the wild-type receptor, respectively. Phosphorylated but not unphosphorylated peptides containing Tyr-1018 are able to compete with the intact receptor for binding to immobilized PLC-gamma SH2 domains; a phosphorylated Tyr-988 peptide competes 10 times less efficiently. The complex between PLC-gamma and the PDGF alpha-receptor is more stable than that of PLC-gamma and the PDGF beta-receptor. However, PDGF stimulation results in a smaller fraction of tyrosine-phosphorylated PLC-gamma and a smaller accumulation of inositol trisphosphate in cells expressing the alpha-receptor as compared with cells expressing the beta-receptor. We conclude that phosphorylated Tyr-988 and Tyr-1018 in the PDGF alpha-receptor carboxyl-terminal tail bind PLC-gamma, but this association leads to only a relatively low level of tyrosine phosphorylation and activation of PLC-gamma.

Characterization of a novel pectate lyase from Erwinia carotovora subsp. carotovora

The pectate lyase (Pel, EC 4.2.2.2) isoenzyme profile of Erwinia carotovora subsp. carotovora was characterized by isoelectric focusing, and the corresponding genes coding for four different exported Pels were cloned. The nucleotide sequence of the pelB gene encoding one of these isoenzymes was determined and was shown to contain 1,040-bp open reading frame coding for a 37,482-Da protein with a putative cleavable amino terminal signal peptide. Overexpression and selective labeling experiments with the pelB clone demonstrated the synthesis of a 35-kDa polypeptide, which is in accordance with the deduced size of the processed PelB. The predicted amino acid sequence of PelB was very similar to that of Pel-3 of another E.c. subsp. carotovora strain 71, but showed no similarity to other previously characterized pectinolytic enzymes. The pelB gene is located next to the previously characterized pehA gene encoding an endopolygalacturonase. The two genes are divergently transcribed from a common control region and are subject to similar global regulation by the central virulence regulator expI. Inactivation of pelB did not appear to reduce the virulence of the mutant strain, suggesting that pelB does not have a major role in pathogenicity. Unlike other Pels, PelB required partially methyl esterified pectin as substrate suggesting that PelB represents a novel isoform of pectate lyase.

The perceptual evaluation of F0 excursions in speech as evidenced in liveliness estimations

In order to learn how listeners evaluate F0 excursions, a set of experiments was performed in which subjects had to estimate the liveliness of utterances. The stimuli were obtained by LPC analysis of one natural utterance that was modified by resynthesizing F0, the formant frequencies, and the time scale in order to simulate some of the natural extra- and paralinguistic variations that affect F0 and/or liveliness, namely the speaker's age, sex, articulation rate, and voice register. In each case, the extent of the F0 excursions was varied in seven steps. The results showed that, as long as the stimuli appeared to have been produced in the modal register (of men, women, and children), listeners judged F0 intervals to be equivalent if they were equal in semitones. When the voice register was shifted without adjustment in articulation, listeners appeared to judge the F0 excursions in relation to the spectral space available below F1. The liveliness ratings were found to be strongly dependent on articulation rate and to be affected by the perceived age of the speaker which, with the manipulated stimuli used here, turned out to be significantly affected by the sex of the listener.

The genomes of the animal papillomaviruses European elk papillomavirus, deer papillomavirus, and reindeer papillomavirus contain a novel transforming gene (E9) near the early polyadenylation site

We report that the genomes of reindeer papillomavirus (RPV), European elk papillomavirus (EEPV), and deer papillomavirus (DPV) contain a short conserved translational open reading frame (ORF), E9, which is located between the E5 ORF and the early polyadenylation site. In RPV, DPV, and EEPV, E9 ORFs have the potential to encode extremely hydrophobic polypeptides of approximately 40 amino acids. In mouse C127 cells transformed by EEPV and RPV, there exists a unique, abundant mRNA species of approximately 700 nucleotides which has the capacity to encode an E9 polypeptide. This mRNA is transcribed from a previously unrecognized promoter at position 4030 in the EEPV genome. The EEPV E9 ORF exhibits weak transforming activity in C127 cells and primary rat embryo fibroblasts. We also show that EEPV E5 is the major oncogene in the EEPV genome when assayed in C127 cells, although it is less efficient in transformation than the E5 genes of bovine papillomavirus type 1, DPV, and RPV.

Would a helmet law for snowmobile riders reduce head injuries?

Swedish authorities have discussed making the use of helmets for snowmobile riders compulsory. To evaluate the possible injury-reducing potential of such a law, 245 non-fatally injured riders and 104 fatalities were analyzed. Non-minor (AIS > 1) head injuries were far less common than in motorcycling, and many fast driving young snowmobile riders seem to use helmets regardless of a law. The persons with head injuries who had not used helmets, or whose helmet use was unknown, had violated other laws, most often the Traffic Temperance Law, or the law forbidding driving on public roads. A helmet law for snowmobile riders will probably not increase the helmet use in this group and consequently have a negligible injury-reducing effect. Helmets are, however, strongly recommended, especially for riders who favour fast driving.

Interleukin-1-induced activation of a protein kinase co-precipitating with the type I interleukin-1 receptor in T cells

We have investigated the possibility of a protein kinase participating in the signal transduction mechanisms of the interleukin-1 (IL-1) type I receptor (IL-1RI). Our data show that a protein kinase was co-precipitated with the IL-1RI from the two murine T helper cell lines D10N and EL-4. The kinase activity was detected in an in vitro kinase assay performed with the immuno beads in the presence of exogenous substrates. IL-1 treatment of the cells resulted in a rapid activation of this protein kinase in a concentration-dependent manner. Both forms of IL-1, IL-1 alpha and IL-1 beta, induced this kinase activity, whereas the IL-1 receptor antagonist (IL-1ra) was inactive. In excess IL-1ra competitively antagonized IL-1 stimulation. In the in vitro kinase assay the exogenous substrates myelin basic protein and histone H1 were phosphorylated, whereas casein or heat-shock protein HSP27 were not accepted, reflecting a certain selectivity of this protein kinase. The IL-1RI co-precipitable protein kinase showed a serine/threonine specificity and was inhibited by staurosporine, but not by inhibitors specific for protein tyrosine kinase or protein kinase C. These results show that a serine/threonine protein kinase directly interacts with the IL-1RI at the plasma membrane level of T helper cells forming a novel type of IL-1 inducible signaling complex. This protein kinase may resemble the link coupling the plasma membrane IL-1 receptor to cytosolic downstream elements in the IL-1 signaling pathway.

Bifunctional role of the bc1 complex in plants. Mitochondrial bc1 complex catalyses both electron transport and protein processing

Nuclear encoded mitochondrial precursor proteins are cleaved to mature size products by the general mitochondrial processing peptidase (MPP). In contrast to non-plant sources where MPP is a matrix enzyme, the plant mitochondrial MPP is localised in the inner membrane and constitutes an integral part of the bc1 complex of the respiratory chain. Core proteins of the complex are immunologically related and show high sequence similarity to the MPP subunits from non-plant sources. The bc1 complex in plants is thus bifunctional, being involved both in respiration and in protein processing.

Brain 5-HT1A, 5-HT1D, and 5-HT2 receptors in suicide victims

We report on 5-HT1A, 5-HT1D, and 5-HT2 binding sites in 23 control subjects and 18 suicide victims subdivided according to the method of death and the previous existence of depressive symptoms. No difference in maximum binding (Bmax) or binding affinity (Kd) was found between the control and overall suicide groups for the binding sites studied. The drug overdose subgroup showed, however, a significant decrease in the 5-HT1A binding affinity, probably explained by the higher sensitivity of this binding site to the acute administration of tricyclic antidepressants. A significant decrease in 5-HT1D binding affinity was also found in the depressed suicides, together with a significant decrease in the number of 5-HT1D binding sites in the nondepressed suicides. Further studies should be carried out on the 5-HT1D binding site as it might represent a new tool in the understanding of the depressive illness.

Adenylyl cyclase activity and G-protein subunit levels in postmortem frontal cortex of suicide victims

Basal and stimulated adenylyl cyclase activities and Gs and Gi protein alpha-subunit levels (Gs alpha and Gi alpha) were compared in postmortem frontal cortex from 18 suicide cases and 22 matched controls. Basal, guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) stimulated and forskolin stimulated enzyme activities were significantly lower in the suicide cases, compared to controls. These effects were most apparent in those suicides that had died from violent means or that had had a history of depression and appeared to reflect the lowered basal activity rather than a reduced ability of either GTP gamma S or forskolin to activate the enzyme. No significant correlations were found between adenylyl cyclase activity and either subject age or postmortem delay. Western blotting revealed no significant differences in Gs alpha and Gi alpha levels between control and suicide cases. However, levels of the smaller Gs alpha isoform (Gs alpha-S) showed a tendency to be increased in the violent death suicide and depressed suicide subgroups, compared to controls. Levels of the larger Gs alpha isoform (Gs alpha-L) showed a significant positive correlation with subject age. Gi alpha levels showed a significant negative correlation with subject age and a positive correlation with postmortem delay. These results support the hypothesis that suicidal behaviour and depressive illness may be associated with an altered regulation of adenylyl cyclase.

Effect of aging in human cortical pre- and postsynaptic serotonin binding sites

5-HT1A, 5-HT1D, 5-HT2 binding sites and affinity and 5-HT uptake sites were simultaneously determined in frontal cortex samples from 23 control subjects, aged 16-75 years. A significant reduction in the number of 5-HT1D and 5-HT2 binding sites was found with regard to age, together with a significant decrease in the 5-HT2 binding affinity. It is suggested that the total 5-HT1 age-related loss described in previous studies could be ascribed to the 5-HT2 subtype. Furthermore, aging does not seem to be associated with a reduced cortical serotonergic innervation, as indicated by the stability of the [3H]paroxetine-labeled 5-HT uptake sites.

Pool of ligand-bound platelet-derived growth factor beta-receptors remain activated and tyrosine phosphorylated after internalization

We have examined the state of tyrosine phosphorylation of ligand-bound, internalized platelet-derived growth factor (PDGF) beta-receptors. Analysis by immunofluorescence staining of cells stimulated with PDGF-BB at 37 degrees C indicated colocalization of phosphotyrosine, PDGF beta-receptors, and PDGF-BB in endosome-like vesicles. Treatment of cells with an acidic buffer, which removed cell surface-bound PDGF-BB, led to a considerable decrease in phosphorylation and kinase activity of cell surface localized PDGF beta-receptors, but not of internalized receptors. Immunoprecipitations using antisera against phosphotyrosine and the PDGF beta-receptor from metabolically labeled cells showed that a major fraction of the tyrosine-phosphorylated pool of receptors were still accessible to the acid buffer treatment after 10 min of incubation of the cells at 37 degrees C. Under these conditions, about 20-25% of the total pool of tyrosine-phosphorylated receptors were intracellular, since they remained tyrosine phosphorylated after the acid buffer treatment. A considerable pool of tyrosine-phosphorylated, internalized receptors, after 10 min of incubation of the cells at 37 degrees C, could also be detected by immunoblotting analysis, using antisera against the PDGF beta-receptor and phosphotyrosine. Analysis by in vitro kinase assays of immunoprecipitated PDGF beta-receptors, obtained from PDGF-BB-stimulated cells different times after acid wash, showed that the internalized receptors retained kinase activity. These data suggest that a pool of internalized PDGF beta-receptors remain active and may participate in signalling a considerable time after internalization.

Pedal cycling fatalities in northern Sweden

The aim of the study was to elucidate the crash and injury mechanisms in bicycle fatalities in the northern half of Sweden. All available autopsy protocols, hospital records and police reports were scrutinized. In 11 years, 146 bicyclists were fatally injured. The majority of the victims were males (66%) and the median age was 60 years. Most of the crashes (81%) occurred from May through October, during weekdays (84%), and during daylight (86%). Almost all victims (88%) died in a motor vehicle collision, in 21% with a truck. None was wearing a helmet. Poor hearing and cerebral arterosclerosis were probable risk factors among the elderly. Of the victims tested, 10% were under the influence of alcohol, half of whom were involved in single-bicycle crashes. In an additional five cases, the motor vehicle driver was impaired by alcohol. All injuries were due to blunt trauma and 69% of the victims died from head injuries. In 91% of all cases, there was an Abbreviated Injury Scale (AIS) score of the head region of > or = 3. The results indicate that separation of bicyclists from motor vehicle traffic by separate cycling tracks and protection of the head by a helmet would be beneficial.

Unique binding characteristics of antipsychotic agents interacting with human dopamine D2A, D2B, and D3 receptors

In the present study we have compared the pharmacological properties of human dopamine (DA) D2A, D2B, and D3 receptors expressed in mammalian cell lines, using [3H]raclopride as a radioligand. Most of the compounds tested had about equal affinity for D2A and D3 receptors, with the exception of remoxipride, which displayed a 10-fold D2 selectivity, and the aminotetralin (+)-UH 232, which displayed a 5-fold D3 selectivity. Several antipsychotic agents, including clozapine and substituted benzamides, bound with 2-3-fold higher to the D2B (short) than to the D2A (long) isoform, whereas others failed to differentiate between the two isoforms. The atypical antipsychotic agent clozapine bound in a biphasic manner and with unexpectedly high affinity (35 nM) to the D2B receptor, suggesting that clozapine may not be as D4 selective as reported previously. In addition, remoxipride, a new antipsychotic agent with low potential to produce extrapyramidal side effects, displayed 2-3-fold higher affinity for the D2B receptor than for the D2A receptor. Furthermore, sodium differently regulated clozapine and benzamide binding to the various DA receptor subtypes. Thus, sodium decreased the affinity of clozapine for D2A and D2B receptors about 3-fold, whereas the affinity for D3 receptors was unaltered. In contrast, the affinity of raclopride for the three DA receptor subtypes was increased by sodium. Whether the unique characteristics of the binding of clozapine and benzamides to cloned DA receptors demonstrated in the present study are related to the favorable clinical properties of these compounds remains to be elucidated.

Single-vehicle crashes and alcohol: a retrospective study of passenger car fatalities in northern Sweden

This retrospective study of fatal passenger car crash victims in northern Sweden compares 396 multiple-vehicle (MV) and 201 single-vehicle (SV) fatalities from 1980 through 1989. Compared to MV fatalities, SV victims were more frequently males, were younger, were more often inebriated, had higher blood alcohol concentrations, had a higher frequency of fatty liver, and were less often restrained. The SV fatalities occurred most often from May through October, from Fridays through Sundays, and from 9 p.m. to 6 a.m. The road surface was usually dry, especially for drunken SV drivers. The SV drivers also more often lacked a valid driver's license. The study confirms that alcohol is one of the most important factors associated with traffic fatalities, particularly in SV crashes. More than half (56%) of the SV victims were inebriated by alcohol (MV, 11%), had a mean blood alcohol concentration of 1.9 g/l (MV, 1.6 g/l), and one-third had a fatty liver (MV, 20%). We also found a relation between fatty liver and increased blood alcohol concentrations, suggesting that studies regarding the role of alcohol in traffic fatalities should also include an evaluation of liver morphology.

Elderly in the traffic environment: analysis of fatal crashes in northern Sweden

Fatal crashes of the elderly (> or = 60 years; N = 379) in northern Sweden in the traffic environment, between 1977 and 1986, were investigated using autopsy and police reports. Males had double the death rate of females. The car occupants made up the largest category (43%) followed by pedestrians, pedalcyclists, and two-wheel-motorvehicle (TWMV) riders, but the risk of fatal injury per unit distance travelled was highest for pedestrians and pedalcyclists. Most car occupants were killed in vehicle-vehicle crashes, mostly in the daylight and at intersections or straight roads. Ice and/or snow (31%) was the major precrash factor. In two-thirds of single car crashes, roadside hazards such as trees were involved. Most elderly fatally injured car drivers were responsible for the crash, and they were commonly involved in collisions with oncoming vehicles. Only 4% of the fatally injured car drivers were driving under the influence of alcohol. Head injuries appeared to be more common in side impact than in frontal impacts. Serious chest injuries were more common than head injuries in car crashes. One-quarter of the pedestrians were injured at pedestrian crossings and about half during darkness. One in six pedestrians were under the influence of alcohol. All pedalcyclists were injured in collisions with motor vehicles and most were injured at intersections. Pedestrians, pedalcyclists, and TWMV riders had more serious head injuries than chest injuries.

Comparison of triphenyltetrazolium chloride (TTC) staining versus detection of fibronectin in experimental myocardial infarction

Staining with triphenyltetrazolium chloride (TTC), although controversial, has frequently been used for the delineation of myocardial infarction. This study was performed further to explore the reliability of the TTC method. In 24-h experiments pigs were subjected to closed-chest occlusion of the left anterior descending coronary artery for 30, 60 or 90 min followed by reperfusion with or without superoxide dismutase (SOD) as an adjunct. One TTC-stained slice from each heart was stabilized by microwave irradiation, gelatin-embedded, frozen in hexane chilled with dry ice and cryosectioned. Serial sections were stained with antibodies against fibronectin in order to identify irreversibly injured myocytes and with van Gieson histologically to confirm the necrotic tissue. A close correspondence of the infarct size was found between TTC stained slices and anti-fibronectin stained sections. The infarct size in the van Gieson stained sections also showed good correspondence but the area of infarction tended to be larger. In the experimental group subjected to 30 min ischaemia and with SOD as an adjunct, the estimated infarcted area in the TTC stained slices was significantly smaller than the area estimated from the anti-fibronectin stained sections. In sections viewed in the light microscope an inverse pattern of TTC and anti-fibronectin staining was observed. It was confirmed at the light microscopic level that myocytes containing an abundance of TTC deposits lacked fibronectin whereas myocytes stained with antifibronectin in general lacked TTC staining except for a zone approximately 0.5 mm wide which was located at the intersection between damaged and surviving myocytes where small TTC deposits were present. The width of the stained zone did not differ among the experimental groups. Thus, differences in estimated infarct size by the three methods used reflect problems in correctly delineating the border between living and dead myocardium rather than an interference by SOD on TTC staining.

Accidental deaths from asphyxia. A 10-year retrospective study from Sweden

Accidental mechanical asphyxia is an unusual cause of death. In reviewing 73 cases occurring during a 10-year-period in Sweden, young boys and elderly women seemed to be most prone to this type of fatality. A striking number of victims had deliberately put a noose-like structure around the neck, and yet another group became entangled in some part of their clothing. Thoracic immobilization was seen in a number of cases, also involving work-related accidents. Hospitalized patients, asphyxiophilics and inebriated victims represent other risk groups. A case involving the use of a helmet is reported in view of the growing frequency with which Swedish children use bicycle helmets. The material contains only a few cases where the victim was not alone at the time of the accident, and it seems plausible that supervision could have prevented many of the reported fatalities. Public knowledge of accident mechanisms may increase the awareness of hazardous situations and activities. Spreading of the medical examiner's knowledge may thus form a basis for accident prevention.