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Biomedical subjects

S Kaspar

Publications and source records attributed to S Kaspar.

10 recordsLinked to original sources
PubMed2006

[Neovascularisation as a cause of recurrence after varicose veins operation].

AIMS: Following surgical therapy, new varicose veins may develop, in particular at the site of the previous saphenofemoral junction. The objective of this study is the appreciation of the causes of the bad results of surgical procedures in the treatment of varicose veins and the proposal of the possibilities of their prevention. MATERIAL AND METHODS: Retrospective study of the group of 404 patients (573 procedures) with the diagnosis of the recurrence after previous radical surgery was performed. After exclusion of perforator refluxes, the most frequently, the great saphenous vein territory was affected (86%), followed by the small saphenous vein territory (14%). The group of 30 consecutive patients (35 limbs) with saphenofemoral or saphenopopliteal recurrence was selected for this study. Based on preoperative ultrasound and per-operative morphological findings, in 12 patients (14 limbs) - 8 women and 4 men, meticulous histopathological examination of the venous tissue block from the saphenofemoral or saphenopopliteal region, VEGF (Vascular endothelial growth factor) and protein S-100 investigation were performed. RESULTS: In 14 limbs with sonographic and clinical suspition for neovascularisation, this entity was confirmed in 11 of them (79%) which represents 31.42% of the whole group. CONCLUSIONS: The varicose veins recurrences can be observed not only after technically or tactically imperfect primary procedure (which is surely the most common cause of the varicose veins recurrence), but also after the operations performed by the experienced venous surgeon in the perfect way. Neovascularisation explains a certain number of postoperative recurrences despite correctly conducted disconnection of the saphenous termination. The endovascular procedures (endovenous laser or radiofrequency saphenous obliteration) without open groin access can minimise the possibility of this complication.

Adult↗
PubMed2005

Infection in hip arthroplasty after previous injection of steroid.

Immunosuppression following intra-articular injections of steroid into the hip may interfere with asepsis in a subsequent total hip arthroplasty (THA). We have undertaken a retrospective, matched, cohort study of infective complications after THA, in 40 patients who had received such an injection and 40 who had not. In the injection group there were five revisions, four of which were for deep infection. There were none in the matched group. The overall rate of revision in our database of 979 primary THAs was 1.02%. Six additional patients who had received injections underwent investigation for infection because of persistent problems in the hip as compared with one in the control group.

Aged↗
PubMed2004

[Endovascular therapy of truncal varicose veins of the lower extremities with a diode laser].

The authors present their experiences with new miniinvasive treatment of varicose veins--endovenous diode laser system. The results of 60 procedures treating truncal varices are reported with special concern to percutaneous access technique under ultrasound guidance. This new concept based on haemodynamic ultrasound findings is compared to the traditional surgical technique of cross-sectomy and stripping.

Adult↗
PubMed2003

Modified iliofemoral approach for major isolated acetabular revision arthroplasty.

Multiple specialized exposures have been described for revision total hip arthroplasty. In this article, we report on a series of 7 patients who underwent major isolated acetabular revision surgery through a modified iliofemoral approach. The use of this approach was deemed desirable because of the individual pathology present in each case, particularly major acetabular bone loss (Paprosky 2C/3B). However, successful reconstruction was achieved in all cases with the most frequent complication being meralgia paresthetica.

Acetabulum↗
PubMed2003

[Surgery of the saphenous-popliteal junction: a delicate procedures with potential risks].

UNLABELLED: The authors evaluate the results achieved in two groups of patients operated on for varicose veins in small saphenous vein (SSV) territory in 3 year interval. In the first group gathered from January to December 1998 (114 patients--36 men and 78 women, 123 procedures--118 primary and 5 re-do) the operative indication was based on the clinical examination and continual doppler evaluation. These patients were operated on in general, spinal or local and flash general anaesthesia. In the second group gathered in the same period of the year 2001 (72 patients--21 men and 51 women) 75 procedures were performed (3 patients with bilateral operation). In this group, 49 patients with 50 procedures were selected. The diagnosis was based not only on clinical and continuous doppler examination, but mainly on colour flow duplex mapping. The operation was performed on strictly ambulatory basis using pure local anaesthesia completed with small dose of sedation. Any patient needed complementary sclerotherapy one month after procedure. In mid-term follow-up complementary conservative treatment was necessary in 51 p.c. of the whole series. CONCLUSION: Use of colour coded duplex ultrasound in preoperative evaluation of varicose veins patients enabled us to precise preoperative diagnosis, to diminish the number of aggressive surgical procedures in favour of less traumatic operations and to perform this surgery on ambulatory basis. Nevertheless, small sahenous vein surgery still remains delicate and sometimes also hazardous.

Adolescent↗
PubMed2001

The phosphinomethylmalate isomerase gene pmi, encoding an aconitase-like enzyme, is involved in the synthesis of phosphinothricin tripeptide in Streptomyces viridochromogenes.

Streptomyces viridochromogenes Tü494 produces the antibiotic phosphinothricin tripeptide (PTT). In the postulated biosynthetic pathway, one reaction, the isomerization of phosphinomethylmalate, resembles the aconitase reaction of the tricarboxylic acid (TCA) cycle. It was speculated that this reaction is carried out by the corresponding enzyme of the primary metabolism (C. J. Thompson and H. Seto, p. 197-222, in L. C. Vining and C. Stuttard, ed., Genetics and Biochemistry of Antibiotic Production, 1995). However, in addition to the TCA cycle aconitase gene, a gene encoding an aconitase-like protein (the phosphinomethylmalate isomerase gene, pmi) was identified in the PTT biosynthetic gene cluster by Southern hybridization experiments, using oligonucleotides which were derived from conserved amino acid sequences of aconitases. The deduced protein revealed high similarity to aconitases from plants, bacteria, and fungi and to iron regulatory proteins from eucaryotes. Pmi and the S. viridochromogenes TCA cycle aconitase, AcnA, have 52% identity. By gene insertion mutagenesis, a pmi mutant (Mapra1) was generated. The mutant failed to produce PTT, indicating the inability of AcnA to carry out the secondary-metabolism reaction. A His-tagged protein (Hispmi*) was heterologously produced in Streptomyces lividans. The purified protein showed no standard aconitase activity with citrate as a substrate, and the corresponding gene was not able to complement an acnA mutant. This indicates that Pmi and AcnA are highly specific for their respective enzymatic reactions.

Aconitate Hydratase↗
PubMed1999

The periplasmic domain of the histidine autokinase CitA functions as a highly specific citrate receptor.

The two-component regulatory system CitA/CitB is essential for induction of the citrate fermentation genes in Klebsiella pneumoniae. CitA represents a membrane-bound sensor kinase consisting of a periplasmic domain flanked by two transmembrane helices, a linker domain and the conserved kinase or transmitter domain. A fusion protein (MalE-CitAC) composed of the maltose-binding protein and the CitA kinase domain (amino acids 327-547) showed constitutive autokinase activity and transferred the gamma-phosphate group of ATP to its cognate response regulator CitB. The autokinase activity of CitA was abolished by an H350L exchange, and phosphorylation of CitB was inhibited by a D56N exchange, indicating that H-350 and D-56 represent the phosphorylation sites of CitA and CitB respectively. In the presence of ATP, CitB-D56N formed a stable complex with MalE-CitAC. To analyse the sensory properties of CitA, the periplasmic domain (amino acids 45-176) was overproduced as a soluble, cytoplasmic protein with a C-terminally attached histidine tag (CitAPHis). Purified CitAPHis bound citrate, but none of the other tri- and dicarboxylates tested, with high affinity (KD approximately 5 microM at pH 7) in a 1:1 stoichiometry. As shown by isothermal titration calorimetry, the binding reaction was driven by the enthalpy change (DeltaH = -76.3 kJ mol-1), whereas the entropy change was opposed (-TDeltaS = + 46.3 kJ mol-1). The pH dependency of the binding reaction indicated that the dianionic form H-citrate2- is the citrate species recognized by CitAPHis. In the presence of Mg2+ ions, the dissociation constant increased significantly, suggesting that the Mg-citrate complex is not bound by CitAPHis. This work defines the periplasmic domain of CitA as a highly specific citrate receptor and elucidates the binding characteristics of CitAPHis.

Bacterial Proteins↗
PubMed1999

Inactivation of the tricarboxylic acid cycle aconitase gene from Streptomyces viridochromogenes Tü494 impairs morphological and physiological differentiation.

The tricarboxylic acid (TCA) cycle aconitase gene acnA from Streptomyces viridochromogenes Tü494 was cloned and analyzed. AcnA catalyzes the isomerization of citrate to isocitrate in the TCA cycle, as indicated by the ability of acnA to complement the aconitase-deficient Escherichia coli mutant JRG3259. An acnA mutant was unable to develop aerial mycelium and to sporulate, resulting in a bald phenotype. Furthermore, the mutant did not produce the antibiotic phosphinothricin tripeptide, demonstrating that AcnA also affects physiological differentiation.

Aconitate Hydratase↗