Biomedical subjects
Publications and source records attributed to J Kingma.
The gender distribution of 246,277 trauma patients was investigated for 9 different categories of accidents. For all categories, a young male peak was observed for the 20-29-yr.-olds. Until the age of 59 years, prevalence of men was clear for all types of accidents. After the age of 60 a reversal to prevalence of women was observed for accidental falls.
Of 4,479 patients treated for injuries in a hospital, the highest frequency of bicycle accidents (23%) was observed in the age group for 20-29-yr.-olds. The main category (68.8%) were accidents without collision with other traffic. The highest mortality rates were found for children below 16 years of age and in elderly > 70 years old in the category of collision with a motor vehicle.
Causes of pedestrian accidents (N = 534) were investigated for patients treated for injuries at the emergency unit of a hospital. Accidents in collisions with motor vehicles were the main cause (87.8%). Young children (0-9 years old) and the elderly (above 60 years of age) are the most vulnerable in terms of mortality rates observed in these age groups. Preponderance of males in pedestrian accidents was observed in the accident categories of collisions with motor vehicle and bicycle, whereas a slight preponderance of females was found in collisions with other traffic. The predominant age groups were located in the range from 0 through 19 years.
25 percent of 2,124 patients, treated for their injuries due to either suicide attempts or automutilation, had consumed alcohol before inflicting themselves with injury. Across the life-span prevalence of males was observed for all age-groups. The highest risk group was located in the age-range between 20 and 29 years.
The preponderance of males in violence was observed in 82.1% of 2,822 victims of assault (treated for injuries at the emergency unit of a hospital). Sex differences were found for site of occurrence of the violent act. Women became victims of violence most frequently (34.6%) at home and men in the street (29.3%).
During the period 1970-1993, 245,251 visits were recorded in the trauma registry of the University Hospital Groningen, The Netherlands. An analysis of injury antecedents revealed five principal causes (ICD-CM): accidental falls (28%), sports and unspecified accident (26%), traffic (19%), cutting and piercing instruments (10%) and violence (4%). The trend analysis across the 24 year period showed that the incidence of injuries due to traffic and accidental falls decreased, while the rate of injuries due to assault increased 2-fold. Within the subgroup of traffic accidents, injuries caused by cars and motorcycles declined, while bicycle accidents increased dramatically. With respect to sex and age, the highest incidence rate occurred in men of 20-29 years. The overall male to female ration was 1.8. A predominance of male patients was observed in all cause categories, except in accidental falls. In this category, a relatively higher incidence of women was observed. The overall mortality rate was 0.5%, with the highest mortality rate being in women over 70 years. The main three causes of fatal injury concerned traffic (66%), falls (16%) and violence (3%). The injury patterns in the present study are in close agreement with patterns of other large trauma populations. Some discrepancies could be discerned. For example, in traffic injury, most of the victims (66%) concerned were pedestrians and bicyclists and firearms comprised only 1.2% of injuries due to assault. The usefulness of the registry in current community trauma care programmes and the broader perspective of trauma registration in The Netherlands is discussed.
Haloalkane dehalogenase from Xanthobacter autotrophicus GJ10 catalyzes the conversion of 1,2-dichloroethane to 2-chloroethanol and chloride without use of oxygen or cofactors. The active site is situated in an internal cavity, which is accessible from the solvent, even in the crystal. Crystal structures of the dehalogenase enzyme complexed with iodoacetamide, chloroacetamide, iodide, and chloride at pH 6.2 and 8.2 revealed a halide binding site between the ring NH's of two tryptophan residues, Trp-125 and Trp-175, located in the active site. The halide ion lies on the intersection of the planes of the rings of the tryptophans. The binding of iodide and chloride to haloalkane dehalogenase caused a strong decrease in protein fluorescence. The decrease could be fitted to a modified form of the Stern-Volmer equation, indicating the presence of fluorophors of different accessibilities. Halide binding was much stronger at pH 6.0 than at pH 8.2. Assuming ligand binding to Trp-125 and Trp-175 as the sole cause of fluorescence quenching, dissociation constants at pH 6.0 with chloride and iodide were calculated to be 0.49 +/- 0.04 and 0.074 +/- 0.007 mM, respectively. Detailed structural investigation showed that the halide binding site probably stabilizes the halide product as well as the negatively charged transition state occurring during the formation of the covalent intermediate.
Heat-labile enterotoxin (LT) from Escherichia coli is a bacterial protein toxin with an AB5 multimer structure, in which the B pentamer has a membrane binding function and the A subunit is needed for enzymatic activity. The LT crystal structure has been solved using a combination of multiple isomorphous replacement, fivefold averaging and molecular dynamics refinement. Phase combination using all these sources of phase information was of crucial importance for the chain tracing. The structure has now been refined to 1.95 A resolution, resulting in a model containing 6035 protein atoms and 293 solvent molecules with a crystallographic R-factor of 18.2% and good stereochemistry. The B subunits are arranged as a highly stable pentamer with a donut shape. Each subunit takes part in approximately 30 inter-subunit hydrogen bonds and six salt bridges with its two neighbors, whilst burying a large surface area. The A subunit has higher temperature factors and less well-defined secondary structure than the B subunits. It interacts with the B pentamer mainly via the C-terminal A2 fragment, which runs through the highly charged central pore of the B subunits. The pore contains at least 66 water molecules, which fill the space left by the A2 fragment. A detailed analysis of the contacts between A and B subunits showed that most specific contacts occur at the entrance of the central pore of the B pentamer, while the contacts within the pore are mainly hydrophobic and water mediated, with the exception of two salt bridges. Only a few contacts exist between the A1 fragment and the B pentamer, showing that the A2 fragment functions as a "linker" of the A and B parts of the protein. Interacting with the A subunit by the B subunits does not cause large deviations from a common B subunit structure, and the 5-fold symmetry is well maintained. A potential NAD(+)-binding site is located in an elongated crevice at the interface of two small sheets in the A1 fragment. At the back of this crevice the functionally important Arg7 makes a hydrogen bond connecting two strands, which seems to be conserved across the ADP-ribosylating toxin family. The putative catalytic residue (A1:Glu112) is located nearby, close to a very hydrophobic region, which packs two loops together. This hydrophobic region may be important for catalysis and membrane translocation.
The ulnar impingement syndrome due to a relatively long ulna is one of the complications of a fracture of the distal radius. We performed ten ulnar-shortening osteotomies to restore distal radioulnar joint congruity. The mean relative ulna length was 4-5 mm. Insufficient bone healing was encountered in four osteotomies. Replating and cancellous bone grafting was necessary in two cases because of nonunion. The functional outcomes were good in six, fair in two, and poor in two cases. Nonunion and poor functional outcome were related to a malunion of the radius with a volar radiocarpal angle of 20 degrees or 25 degrees. It appeared that incongruity of the distal radioulnar joint favored nonunion.
The alkane hydroxylase system of Pseudomonas oleovorans, which catalyses the initial oxidation of aliphatic substrates, is encoded by three genes. One of the gene products, the alkane hydroxylase AlkB, is an integral cytoplasmic membrane protein. Induction leads to the synthesis of 1.5-2% AlkB relative to the total cell protein, both in P. oleovorans and in recombinant Escherichia coli DH1. We present a study on the induction and localization of the alkane hydroxylase in E. coli W3110, which appears to be an interesting host strain because it permits expression levels of AlkB of up to 10-15% of the total cell protein. This expression level had negative effects on cell growth. The phospholipid content of such cells was about threefold higher than that of wild-type W3110. Freeze-fracture electron microscopy showed that induction of the alk genes led to the appearance of membrane vesicles in the cytoplasm; these occurred much more frequently in cells expressing alkB than in the negative control, which contained all of the alk genes except for alkB. Isolation and separation of the membranes of cells expressing alkB by density gradient centrifugation showed the customary cytoplasmic and outer membranes, as well as a low-density membrane fraction. This additional fraction was highly enriched in AlkB, as shown both by SDS-PAGE and enzyme activity measurements. A typical cytoplasmic membrane protein, NADH oxidase, was absent from the low-density membrane fraction. alkB expression in W3110 changed the composition of the phospholipid headgroup in the membrane, as well as the fatty acid composition of the membrane. The major changes occurred in the unsaturated fatty acids: C16:1 and C18:1 increased at the expense of C17:0cyc and C19:0cyc.
We compared the Abbreviated Injury Scale (AIS-85) and the Hospital Trauma Index (HTI) in seriously injured patients. The effect of these scales on the application of Injury Severity Scores (ISS) was investigated. Furthermore, the predictive value on mortality of the AIS/ISS and the HTI/ISS was determined. Subjects were 932 seriously injured patients (HTI/ISS score greater than or equal to 18) admitted to University Hospital Groningen between 1985 and 1990. A quantitative and a qualitative comparison were performed. Logistic regression was used to estimate the predictive value of the AIS/ISS and the HTI/ISS on mortality. The AIS/ISS and HTI/ISS differed quantitatively and qualitatively. The average HTI/ISS score was ten points higher than the average AIS/ISS. By combining specific regions of the scales the predictive value could be improved. The ISS scores were incomparable. Consequently in future studies the method used to calculate the ISS score should be mentioned.
The comparability of surveys is often hampered by differences in the item order of presentation. The major focus of the present study was to investigate whether a general item or a specific item at the beginning of the questionnaire would affect the endorsement as well as the scalability of a set of attitude items. By using a quasi-A-B-A experimental design for the six abortion items that appeared in the Edmonton Area Survey for the years 1984, 1987, and 1988, we found that the order of presentation of the items affected dramatically the endorsement of the abortion items. Approval of a general item was considerably higher when asked first than when asked after a specific item. In contrast, it was shown by means of a nonparametric item response theory model (the Mokken scale analysis) that the unidimensionality of the six abortion items was not affected by the manipulations of item order (i.e., the six abortion items measured the same concept in the three surveys). It was concluded that the six items are unidimensional and, therefore, create a single scale to measure the change in abortion attitudes across the three periods.
The alk genes from the catabolic OCT plasmid of Pseudomonas oleovorans, which encode the enzymes involved in the oxidation of n-alkanes to carboxylic acids, were introduced into E. coli W3110. The resulting recombinant converts n-octane in a two-liquid phase medium into the corresponding alkanoate and excretes this compound into the aqueous phase. The rate of octanoic acid production by the recombinant E. coli is equal to or better than the alkane oxidation rate of P. oleovorans, suggesting that two-liquid phase fermentations with E. coli might have future industrial applications.
The pncB gene from Escherichia coli, which encodes nicotinic acid phosphoribosyltransferase (EC 2.4.2.11), was cloned on a 1.5-kilobase TaqI-EcoRI fragment. Its position on the E. coli chromosome was determined at 20.8 min between the asnS and pepN loci. The nucleotide sequence of the gene and the transcription and translation initiation sites were determined. Expression of pncB on a multicopy plasmid leads to a 25-fold increase in nicotinic acid phosphoribosyltransferase activity. Growth of E. coli in the presence of nicotinic acid leads to strong repression of nicotinic acid phosphoribosyltransferase activity, indicating that the cloned pncB sequence contains its own control sequences. It is shown that increased nicotinic acid phosphoribosyltransferase activity effects a 5-fold increase in the intracellular concentration of NAD. The cloned pncB gene can therefore be used as a tool to raise intracellular cofactor levels.
Pseudomonas oleovorans can grow on linear alkanes and alkenes in the hexane to dodecane range by virtue of enzymes encoded by the alk genes. By introducing selected alk genes into Pseudomonas strains and by supplying alkanes in the growth medium as a bulk liquid phase, specific alkane oxidation products can be accumulated in the alkane phase. We review the genetics and enzymology of the alk system and the potential of bioconversions in two-liquid-phase bioreactors, and suggest that such systems might eventually allow the biotechnological production of intermediate value compounds.
Many theoretical positions on memory development anticipate that forgetting rates should vary substantially with age. The nature of these age variations is also relevant to many applied questions about child development that have major social policy implications, such as the veracity of children's eyewitness testimony and the long-term effectiveness of classroom instruction. Surprisingly, developmental studies of long-term retention have repeatedly produced the puzzling finding that forgetting rates are age invariant. It now seems, however, that these null age trends may have been artifacts of variables such as measurement insensitivity, floor effects, and stages-of-learning confounds. Assuming, as some later studies suggest, that forgetting rates vary with age when these factors are controlled, there are three overriding questions that must be dealt with in the developmental analysis of forgetting: the relative importance of storage failure versus retrieval failure, the relative importance of true forgetting processes versus test-induced processes, and the relative importance of storage-based reminiscence versus retrieval-based reminiscence. We describe a framework (disintegration/redintegation theory) that provides a conceptual environment within which research on these questions can progress. This framework, which evolved from fuzzy-trace theory, reinterprets processes such as storage failure, retrieval failure, restorage, and retrieval relearning in terms of levels of featural integration in traces (i.e., the extent to which contextual information is integrated with core semantic gist to produce a coherent representation). The theory is implemented in a mathematical model (the trace-integrity model) whose parameters deliver measurements of relevant memory processes on a common ratio scale. In a series of experiments, the model was used to study the theory's predictions about the contributions of these memory processes to long-term retention in subjects between the ages of 7 and 70. All the experiments were standard long-term retention designs (an initial acquisition session, followed by a 1-2-week forgetting interval, followed by a series of retention tests).(ABSTRACT TRUNCATED AT 400 WORDS)
We have identified and sequenced the Pseudomonas OCT plasmid-encoded alkane hydroxylase gene (alkB) and its promoter. The transcription initiation site of the alkBAC mRNA was determined by nuclease S1 mapping. A putative interaction site with RNA-polymerase was identified based on homology of the alk promoter with other Pseudomonas promoters. The alkB gene encodes a 401-amino acid polypeptide which, despite an unusual codon composition, can be expressed at high levels in Escherichia coli and Pseudomonas. The amino-terminal sequence of the purified cytoplasmic membrane alkane hydroxylase was determined and was found to be in agreement with the nucleotide sequence. The translation product of the alkB gene contains nine hydrophobic sequences of which eight are sufficiently long to be membrane-spanning segments. The amino-terminal sequence resembles that of several bacterial integral membrane proteins and is not cleaved off following translation.
The Pseudomonas oleovorans alkBAC operon encodes seven proteins, of which at least three are involved in alkane hydroxylase (alkBA) and alkanol dehydrogenase (alkC) activities. We have determined the nucleotide sequence of the 2.5-kilobase pair alkA region and analyzed the role of its translation products in alkane oxidation. The alkA region contains three coding sequences, encoding two related rubredoxins (alkF and alkG) of 14- and 18-kDa molecular mass and a 52-kDa aldehyde dehydrogenase (alkH). Deletion analysis indicated that neither the 14-kDa alkF gene product (rubredoxin 1) nor the amino-terminal part of the 18-kDa alkG gene product (rubredoxin 2) is required for alkane hydroxylase activity in vivo. The product of the alkH cistron restores growth of a P. oleovorans aldehyde dehydrogenase mutant on aliphatic alcohols and aldehydes. Its amino acid sequence shows considerable homology to previously characterized aldehyde dehydrogenases from mammalian and fungal origin. The nucleotide composition of the alk genes (47% G + C) differs considerably from the G + C content of the P. oleovorans genome suggesting that the alk regulon may originate from an unrelated organism.