Fixation strength and pin tract infection of hydroxyapatite-coated tapered pins.

In a multicenter, prospective, randomized study, the biomechanical and clinical properties of the bone-pin interface were compared with standard tapered pins and hydroxyapatite-coated tapered pins implanted in patients who underwent femoral and tibial external fixation treatments. The results showed that the hydroxyapatite-coated tapered pins are clinically effective in improving the strength of fixation of the bonepin interface. This improvement corresponded to a lower rate of pin tract infection. In the hydroxyapatite-coated pin group, there were no differences in strength of fixation between the pins removed from the infected and uninfected pin tracts. In this pin group, the mean pin extraction torque was 531 +/- 225 Ncm in the infected pin tracts and 508 +/- 233 Ncm in the uninfected pin tracts. In the standard pin group, the mean pin extraction torque was 73 +/- 142 Ncm in the infected pin tracts and 211 +/- 216 Ncm in the uninfected pin tracts. The advantages provided by the hydroxyapatite-coated pins were higher in cancellous bone than in cortical bone.

Open-wedge osteotomy by hemicallotasis or the closed-wedge technique for osteoarthritis of the knee. A randomised study of 50 operations.

We describe the results of 50 operations carried out on 46 patients with medial osteoarthritis of the knee of Ahlbäck grade 1 to 3. Patients were randomised either to a closed-wedge high tibial osteotomy (HTO) or an open-wedge procedure based on the hemicallotasis technique (HCO). Their median age was 55 years (38 to 68). The preoperative median hip-knee-ankle (HKA) angle was 171 degrees (164 to 176) in the HTO group and 173 degrees (165 to 179) in the HCO group. After six weeks, the median HKA angle was 185 degrees (176 to 194) in the HTO group and 184 degrees (181 to 188) in the HCO group. In the HTO group, seven patients were within the range of 182 degrees to 186 degrees compared with 21 in the HCO group (p < 0.001). One year later, ten HTO patients were within this range while the HKA angulation in the HCO group was unchanged. At two years the numbers were 11 and 18, respectively. We evaluated the clinical results on the Hospital for Special Surgery, Lysholm and Wallgren-Tegner activity scores, and patients completed part of the Nottingham Health Profile questionnaire. An impartial observer at the two-year follow-up concluded that all scores had improved, but found no clinical differences between the groups.

Hemicallotasis open-wedge osteotomy for osteoarthritis of the knee. Complications in 308 operations.

We studied the complications after open-wedge osteotomy by hemicallotasis in 308 consecutive patients, most of whom had osteoarthritis of the knee. The participating surgeons, who worked at 17 hospitals, used their discretion in selecting patients, operating techniques and external fixators. The general complications included 11 cases of deep-vein thrombosis (4%), six of nonunion (2%) and one of septic arthritis of the knee. There were technical complications in 13 patients (4%). In 157 patients (51%) pin-site infections were recorded; of these, 96% were minor and responded to wound toilet and antibiotic treatment. A total of 18 revision procedures was carried out.

Frequent complications in distal femoral osteotomy: a retrospective 8 year multicenter follow-up.

A total of 32 distal femoral osteotomies performed between 1971 and 1993 were evaluated, with a follow-up of 8 (2-23) years. Indications were lateral gonarthrosis in 23 cases (group I), and there were a variety of other indications in 9 cases (group 2). Twenty-six of the patients were submitted to revision surgery. Eleven operations were performed as a result of complications, such as pseudarthrosis (5), deep infection (3), and stiff knee (3). The remaining 16 were removals of fixation devices and they were not considered complications. Clinical results were evaluated based on different clinical scores (HSS, Lysholm, and Tegner) and NHP (Nottingham Health Profile), and there were 10 cases with good or excellent results. Results were better if the postoperative HKA angle (Hip-Knee-Ankle) was within 0-8 degrees of varus. As accuracy of correction is of importance, and serious complications frequent, it is important to entrust cases such as these to the care of surgeons with a good knowledge of the surgical technique.

Changes in osseous correction after proximal tibial osteotomy: radiostereometry of closed- and open-wedge osteotomy in 33 patients.

33 patients (22 men), median age 54 (40-68) years, with medial gonarthrosis grades 1-3, were treated by closed-wedge osteotomy (high tibial osteotomy = HTO, n 16) or open-wedge osteotomy by hemicallotasis (hemicallotasis osteotomy = HCO, n 19). 2 patients were operated on bilaterally. The patients were studied by RSA (radiostereometric analysis) for measuring 3-D changes in the correction achieved. In the HTO group the RSA measurements were obtained at the time of plaster removal, 1 month later and 1 year after surgery. In the HCO group, the RSA measurements were performed at the time of removal of the external fixator, 1 month later and 1 year after surgery. After removal of the fixation, HTO was associated with increased medial/lateral and distal translation of the proximal segment, compared to HCO. In addition, the tibial plateau rotated more around the longitudinal axis of the tibia after HTO.

Prevention of deep vein thrombosis in knee arthroplasty. Preliminary results from a randomized controlled study of low molecular weight heparin vs foot pump compression.

BACKGROUND: We evaluated in a randomized controlled study the possibility to use foot pump mechanical compression compared to routine LMWH as prophylaxis against deep vein thrombosis during knee arthroplasty. METHODS: Forty patients were included in this preliminary report. Eleven patients withdrew, usually during the early phase of the study. RESULTS: Among the 29 patients completing a venography, 27% in the compression group and none in the LMWH group had a DVT. This difference was statistically significant (p<0.05). One further patient in the compression group died from pulmonary embolism 17 days postoperatively. CONCLUSIONS: With the present study protocol, mechanical foot pump compression failed to be as efficient as LMWH prophylaxis.

Conversion of VP1 to VPg in cells infected by infectious pancreatic necrosis virus.

The RNA polymerase VP1 of IPNV (a bisegmented dsRNA containing virus) is present in the virion both as a free polypeptide and as a genome-linked protein (VPg). Virion VP1 primes viral RNA synthesis in vitro (P. Dobos, 1995, Virology 208, 19-25), and here we present data which suggest that protein-primed RNA synthesis may also take place in infectious pancreatic necrosis virus (IPNV)-infected cells. Anti-VP1 serum immunoprecipitated several polypeptides larger than the 94-kDa VP1 of IPNV from [35S]methionine-labeled infected cell lysates. During denaturing, SDS-polyacrylamide gel electrophoresis these polypeptides formed a characteristic "ladder" which was resistant to alkaline phosphatase but sensitive to RNases, indicating that it consisted of VP1 polypeptides with oligoribonucleotides of various lengths attached to them. Probing the ladder with 5' and 3' end-specific, as well as plus-, or minus-strand-specific oligonucleotides revealed that they represent VP1 linked to 5' terminal sequences of genome segment A- and B-specific plus strands. Pulse-chase experiments in combination with two-dimensional polyacrylamide gel electrophoresis revealed that labeled VP1 could be chased to replicative intermediate, to ssRNA, to dsRNA, and eventually to virion VPg-dsRNA and that VP1 could be released from all these structures by RNase treatment. We suggest that these results are most compatible with the model where a VP1-pN structure acts as a primer for viral RNA synthesis in vivo, a mechanism that has been shown to occur in vitro.

Open wedge tibial osteotomy by callus distraction in gonarthrosis. Operative technique and early results in 36 patients.

Proximal tibial osteotomy is indicated in cases of medial gonarthrosis with varus deformity in the active, younger patient. We report our experience of the hemicallotasis technique in 36 patients and the early clinical results after a median follow-up of 14 (11-16) months. The median patient age was 54 (33-64) years. The median hip-knee-ankle (HKA) angle was 172 (161-179) degrees preoperatively, 184 (178-187) degrees after completed correction and 183 (175-190) degrees at follow-up. The median fixation time was 88 (61-146) days. Complications were minor. Superficial pin-site inflammation/infections occurred in one fifth of the pins. The HSS score increased from a median 71 preoperatively to 94 at follow-up, the Lysholm score from 56 to 91 and the Tegner activity score from 6 to 10. The Nottingham Health Profile showed significant improvements as regards pain and physical mobility.

Fixation of the tibial component of total knee arthroplasty after high tibial osteotomy: a matched radiostereometric study.

To assess migration of the tibial component we used roentgen stereophotogrammetric analysis in 40 patients who had had a total knee arthroplasty after failure of a closing wedge osteotomy and compared them with 40 matched patients after primary total knee arthroplasty. We found no difference in migration over time or in the tendency for continuous migration between the two groups. There were no differences in alignment or position of the knee prosthesis or in the clinical outcome. Our findings show that revision of a failed high tibial osteotomy to a total knee arthroplasty is effective.

The bovine herpesvirus type 1 UL3.5 open reading frame encodes a virion structural protein.

The bovine herpesvirus type 1 (BHV-1) open reading frame (ORF) UL3.5 is similar to ORFs found in pseudorabies virus, infectious laryngotracheitis virus, equine herpesvirus type 1, and varicella zoster virus, but clearly absent from herpes simplex virus. The published sequence for this ORF predicts a 126-amino-acid (13.2 kDa) protein product with an isoelectric point of 12.3. We confirmed the UL3.5 sequence, expressed the ORF as a glutathione-S-transferase fusion protein, and made rabbit antibodies against the purified fusion protein. The antiserum detected a 13-kDa protein in Western blots of MDBK cells infected with BHV-1, but not with other herpesviruses or uninfected cells. The BHV-1 UL3.5 protein was characterized as a component of the virion envelope or tegument because it was expressed as a late protein, it was present in the cytoplasm but not the nucleus of infected cells, and it was removed from purified virions by detergent extraction.

Hydroxyapatite coating of threaded pins enhances fixation.

We measured the insertion and extraction torque forces in a randomised study of 76 external fixation screws in 19 patients treated by hemicallotasis for osteoarthritis of the medial side of the knee. The patients were randomised to have either standard tapered screws (Orthofix 6/5 mm) or the same screws with hydroxyapatite (HA) coating. One patient had two standard and two HA-coated screws. All patients had an anterior external fixator (Orthofix T-garche), with two screws in the proximal tibial metaphysis parallel to and about 2 cm below the joint surface and two in the tibial diaphysis. The mean torque forces for insertion of the standard screws were 260 Ncm for the proximal to medial screw, 208 for the proximal to lateral screw and 498 and 546 Ncm for the diaphyseal pins. The corresponding forces for the HA-coated pins were not significantly different. The torque forces for the extraction of the standard pins were 2 Ncm for the proximal pins, 277 and 249 Ncm for the distal pins and 482, 478, 585 and 620 Ncm, respectively (p < 0.005) for the HA-coated pins. All 18 of the metaphyseal standard screws were loose at extraction (extraction force < 20 Ncm), but only one of the HA screws in the metaphysis was loose. In the diaphysis the standard screws lost about 40% of their fixation in contrast to the HA-coated screws which retained full fixation strength.

Evolution of a regional health-care information system--the design phase.

In 1996 a program of the Soros Foundation was launched to study a regional health care inodel Main stake holders of health care financing and providing in three counties in South-Western Hungary found the idea appealing and the Soros Model Region Program was started. This paper outlines the activity of the second sub-project of the model region program: the development of a regional health care information system. The build-up of a data and knowledge base serving the differing needs of mentioned goals is based on international standards. Availability and user involvement is based on different media for presenting the information as printed publications, CD-ROM data bases and World Wide Web availability. A congruency and coherency principle is maintained by a unified data model used for different purposes and a planned unified communication protocol among all participants in the model region program. Studies regarding health care status, economics and financing on regional level show that a better fitting health care services profile and a more flexible resource management might be achieved based on the mentioned regionality principle.

Incomplete dsRNA genomes in purified infectious pancreatic necrosis virus.

The dsRNA containing birnavirus, infectious pancreatic necrosis virus, possesses a virion-associated RNA-dependent RNA polymerase which acts both as primer and as polymerase during in vitro RNA synthesis (P. Dobos, 1995, Virology 208, 19-25). Using [alpha 32P]GTP, we have radiolabeled virion RNA in vitro and found that after deproteinization most of the labeled product comigrated in agarose gels with the 3-kbp viral genome, while the remainder migrated faster than the dsRNA and as a heterogeneous smear. Agarose gel electrophoresis (AGE) of denatured labeled virion RNA showed a radioactive smear ranging from approximately 100 nucleotides to up to 3000 nucleotide the size of genome length single stranded RNA. Hybridization experiments using strand-specific and end-specific obligonucleotides on Northern blots revealed that the radioactivity which migrates with the dsRNA during AGE represents small, 5' end plus RNA molecules of 100-500 nucleotides. The radioactivity in the faster migrating smear denotes incomplete dsRNAs where full-length, unlabeled minus strands are base-paired with labeled plus strands that are 3' truncated to different extents. This was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) using end- and strand-specific obligonucleotide primers. The results indicated that 95% of incomplete dsRNA molecules consisted of full-length minus strands and 3' truncated plus strands. The implications of these findings are discussed in light of RNA replication mechanisms of dsRNA viruses belonging to other families.

Evidence for the detection of the infectious pancreatic necrosis virus polyprotein and the 17-kDa polypeptide in infected cells and of the NS protease in purified virus.

The larger genome segment A of infectious pancreatic necrosis virus (IPNV) contains two open reading frames (ORFs): (i) the large ORF encodes a 106-kDa polyprotein (PP) (NH2-pVP2-NS-VP3-COOH) which is cotranslationally cleaved by the NS protease to generate the major capsid polypeptides VP2 and VP3; (ii) the second small ORF, which overlaps the 5' end of the PP ORF but in a different reading frame, encodes a 17-kDa arginine-rich polypeptide. Hitherto, neither the PP nor the 17-kDa polypeptide have been identified in infected cells, and the NS (nonstructural) polypeptide was thought not to be part of the virion. The smaller genome segment B of IPNV encodes a 94-kDa minor polypeptide VP1. Using recombinant baculoviruses expressing VP1 and PP as markers, the PP could be unambiguously identified in Western blots of infected fish-cell lysates and in purified IPNV. Anti-17-kDa and anti-NS serum was produced by injecting rabbits with bacterially expressed fusion proteins containing these polypeptides. Labeled 17-kDa polypeptide was immune-precipitated from infected cell lysates using the anti-17-kDa serum, whereas the NS and NSt (a truncated form of NS) polypeptides were identified in infected cells by immune precipitation and Western blotting using the anti-NS serum. Western blots of purified virus revealed two forms of truncated NS: (i) the NSt found in infected cells and (ii) a smaller polypeptide NSta. The identity of the virion NSt/NSta was also demonstrated by peptide mapping.

Stability of oxytetracycline hydrochloride in eye-drops, prepared in pharmacies.

In the ophthalmological practice the so-called "Oxytetracycline-eye-drop" is frequently used, prepared in pharmacies ex tempore with a short self-life (3 days). In this paper a TLC-densitometric method is described for the determination of the degradation products of oxytetracycline HCl (OTC) formed in the "Oxytetracycline-eye-drop". A chloroform-methanol-water (65 + 25 + 5 v/v) solvent system is applied on silica gel TLC plate, predeveloped with saturated disodium ethylenediamine-tetraacetate aqueous solution. UV densitometry at 254 nm is used for quantitative determination. The chemical stability of OTC in different eye-drops as well as the effects of the pH and the mode of the preparation and storage conditions on the decomposition process are discussed.

Expression of infectious pancreatic necrosis virus polyprotein and VP1 in insect cells and the detection of the polyprotein in purified virus.

In order to study the molecular biology of infectious pancreatic necrosis virus (IPNV) replication, six different recombinant baculoviruses were constructed. The following four recombinants contained genome segment A-specific sequences; (i) AcPP contained the complete polyprotein coding region and Spodoptera frugiperda (Sf) cells infected by these recombinants synthesized the 106-kDa polyprotein (NH2-preVP2-NS protease-VP3-COOH), which was only partially processed by the protease to yield preVP2 and VP3 and unprocessed polyprotein; (ii) AcPP(S) and AcPP(Ss) represented 3' truncated sequences of the segment A cDNA where the VP3 coding region and that coding for 30 and 98 carboxy terminal amino acids of NS in the two constructs, respectively, were deleted. AcPP(S) demonstrated partial, and that of AcPP(Ss), complete loss of proteolytic activity, demonstrating that the carboxy one-third of the 29-kDa NS protease is necessary for the formation of the active enzyme; and (iii) AcPP(B/B) contained all but the first 180 nt of the pVP2 gene, the complete NS coding region, and the amino end of VP3. Analysis of cells coinfected with AcPP(Ss) and AcPP(B/B) showed either that the protease did not work in trans or that the alteration of the structure of the substrate prevented cleavage. Recombinant baculoviruses AcVP1VL and AcVP1ETL contained IPNV genome segment B cDNA encoding the 94-kDa VP1 which is the viral RNA-dependent RNA polymerase. AcVP1VL contained the whole segment B cDNA, whereas in AcVP1ETL, the 5' non-coding sequences were deleted resulting in the production of large amounts of VP1 when Sf cells were infected with this recombinant. The use of recombinants AcPP and AcVP1ETL as well as monoclonal antibodies and VP1-specific sera allowed the unambiguous identification of the high molecular weight minor polypeptides present in purified IPNV demonstrating the presence of both VP1 and the polyprotein in purified virus preparations.

Evaluation of "sequence-tagged-site" PCR products as molecular markers in wheat.

The polymerase chain reaction (PCR) is an attractive technique for many genome mapping and characterization projects. One PCR approach which has been evaluated involves the use of randomly amplified polymorphic DNA (RAPD). An alternative to RAPDs is the sequence-tagged-site (STS) approach, whereby PCR primers are designed from mapped low-copy-number sequences. In this study, we sequenced and designed primers from 22 wheat RFLP clones in addition to testing 15 primer sets that had been previously used to amplify DNA sequences in the barley genome. Our results indicated that most of the primers amplified sequences that mapped to the expected chromosomes in wheat. Additionally, 9 of 16 primer sets tested revealed polymorphisms among 20 hexaploid wheat genotypes when PCR products were digested with restriction enzymes. These results suggest that the STS-based PCR analysis will be useful for generation of informative molecular markers in hexaploid wheat.

Repetitive DNA variation and pivotal-differential evolution of wild wheats.

Several polyploid species in the genus Triticum contain a U genome derived from the diploid T. umbellulatum. In these species, the U genome is considered to be unmodified from the diploid based on chromosome pairing analysis, and it is referred to as pivotal. The additional genome(s) are considered to be modified, and they are thus referred to as differential genomes. The M genome derived from the diploid T. comosum is found in many U genome polyploids. In this study, we cloned three repetitive DNA sequences found primarily in the U genome and two repetitive DNA sequences found primarily in the M genome. We used these to monitor variation for these sequences in a large set of species containing U and M genomes. Investigation of sympatric and allopatric accessions of polyploid species did not show repetitive DNA similarities among sympatric species. This result does not support the idea that the polyploid species are continually exchanging genetic information through introgression. However, it is also possible that repetitive DNA is not a suitable means of addressing the question of introgression. The U genomes of both diploid and polyploid U genome species were similar regarding hybridization patterns observed with U genome probes. Much more variation was found both among diploid T. comosum accessions and polyploids containing M genomes. The observed variation supports the cytogenetic evidence that the M genome is more variable than the U genome. It also raises the possibility that the differential nature of the M genome may be due to variation within the diploid T. comosum, as well as among polyploid M genome species and accessions.

Restriction endonuclease analysis of Hungarian bovine herpesvirus isolates from different clinical forms of IBR, IPV and encephalitis.

The DNA of thirty-three Hungarian bovine herpesvirus isolates originating from cattle with various clinical symptoms were compared by restriction endonuclease analysis using HindIII, EcoRI and BstEII enzymes. The EcoRI and HindIII cleavage patterns were similar to those of isolates studied in other countries. Based on the cleavage patterns, the Hungarian isolates could be assorted into groups and subgroups according to the classification system proposed by Metzler et al. (1985, 1986). Based on a new BstEII cleavage pattern observed in group 1, the establishment of two new subgroups, 1a and 1b, were proposed. Three isolates belonged to subgroup 1a, sixteen to 1b, seven to 2a, five to 2b, and one to group 3, which has recently been reclassified as BHV-5. Additionally, one of the isolates showed a mixed cleavage pattern of 1a and 1b. However, no strict correlation was found between the different clinical forms and the established DNA fingerprint groups. There was no evidence of a change in the prevalence of the different genotypes when comparing isolates collected at different times of a 24-year period.