Efficacy of the dorsal pedal bypass for limb salvage in diabetic patients: short-term observations

Limbs of diabetic patients with distal tibial disease are frequently considered unreconstructible; however, when studied with intraarterial digital subtraction angiography, the dorsal pedal artery is frequently found to be patent. We have reviewed our recent experience with 96 patients, 94% of whom had diabetes and had 97 bypasses placed to the dorsal pedal artery. All procedures were for limb salvage. Superimposed infection was present in 42.3%. In 92 instances where intraarterial digital subtraction angiography successfully visualized the dorsal pedal artery, 91 bypasses were placed. In 12 other cases where the dorsal pedal artery was not visualized by intraarterial digital subtraction angiography but audible with the continuous-wave Doppler, bypasses were completed successfully in six. All procedures were performed with vein. Inflow was taken from the femoral artery in 48, popliteal artery in 45, tibial artery in 2, and from a femoral tibial graft in 2. Perioperative mortality was 1.92%. Actuarial graft patency, limb salvage, and patient survival were 82%, 87%, and 80%, respectively at 18 months. We conclude that bypass grafting to the dorsal pedal artery can be reliably performed with acceptable short-term results. An attempt should always be made to visualize the foot vessels angiographically, especially in diabetic patients, so that this valuable option in arterial reconstruction will not be overlooked.     

Progressive peri‐implantitis. Incidence and prediction of peri‐implant attachment loss.

The aim of this prospective study was to characterize an implant patient population exhibiting clinical signs of peri‐implantitis and to determine subsequently the incidence of progressive attachment loss. The predictive values of diagnostic parameters were evaluated. 25 patients with 54 endosseous implants that had been loaded for 41±15 months were included in the study. Clinical parameters included the assessment of plaque, bleeding on probing, probing depth, attachment levels, and Periotest® values. Probing measurements were performed in duplicate by means of a controlled force electronic probe (Periprobem). Peri‐implant crevicular fluid samples were collected and assayed for neutral proteolytic enzyme (NPE) activity (Periocheck®). Analysis of duplicate baseline probing data revealed a high degree of reproducibility (mean difference: 0.1±0.3mm). A minimum threshold of 1.0mm (>3×S.D.) loss of probing attachment was chosen to classify a site as positive for breakdown. Alternatively, the tolerance method was employed to identify sites with progressive attachment loss. After 6 months, irrespective of the analytical method, 6 percent of all sites (in 19% of the implants) and 28% of the patients had experienced further per attachment loss. There were significant differences ( p <0.05) in mean plaque (73% vs. 45%) and NPE (36% vs. 12%) scores between patients with progressive peri‐implantitis and those with stable peri‐implant conditions. Both bleeding on probing and the NPE‐test were characterized by high negative predictive values, and thus negative scores can serve as indicators for stable peri‐implant conditions. For monitoring peri‐implant health during recall visits, attachment level recordings with a controlled force electronic probe in conjunction with enzymatic diagnostic tests of the host response can be recommended.     

Tumor vascular signals in renal masses: detection with Doppler US

The vascularity of 49 renal masses (26 malignant and 23 benign lesions) was investigated with duplex Doppler ultrasound. Doppler signals obtained at the margins of renal masses were defined as "tumor signals" when the Doppler-shifted frequency of the lesion exceeded the frequency shift in the ipsilateral main renal artery. These exceeded 2.5 kHz with a 3-MHz insonating frequency. Among the 26 renal masses that subsequently proved to be malignant, tumor signals were obtained in 15 of 18 (83%) untreated renal cell carcinomas, in three of four Wilms tumors, and in two patients with metastases to the kidney, but not in the one patient with lymphoma. None of the 23 benign renal masses demonstrated tumor signals. Tumor vascularity in malignant lesions gives rise to abnormal, high-velocity, Doppler-shifted signals that can help in the differential diagnosis of renal masses.     

Regulatory effects of biophysical strain on rat TMJ discs

Recent studies have revealed that dynamic biomechanical forces can exert antiinflammatory and antiproteolytic effects on fibrocartitage. Whether the effects of mechanical strain also involve stimulation of the insulin-like growth factor (IGF) system and, therefore, of growth and repair of fibrocartilage has yet to be determined. The objective of this in vitro study was to determine if continuous biophysical strain regulates the gene expression of IGF1, IGF2, IGF1 receptor (IGF1R), insulin receptor substrate (IRS1), and IGF-binding proteins (IGFBP) 3 and 5 in cells from the fibrocartilaginous disc of the temporomandibular joint (TMJ). Rat TMJ disc cells were subjected to continuous biophysical strain (3% and 20%) for 4 and 24 h. Subsequently, RNA was extracted and real-time PCR was performed using an iCycler iQ detection system to analyze the gene expression of the IGF system. The gene expression of IGF1, IGF2, IGF1R, IRS1, IGFBP3, and IGFBP5 was significantly (p < 0.05) inhibited when cells were subjected to continuous biophysical strain, as compared to control at both time points. High strain induced a stronger inhibition of these molecules as compared to strain of Low magnitude. In conclusion, continuous biophysical strain seems to downregulate the expression of the IGF system and may, therefore, reduce the potential of fibrocartilage for growth and repair.     

Soluble Plasmodium falciparum antigens contain carbohydrate moieties important for immune reactivity.

The importance of carbohydrate moieties for the antigenicity of purified soluble Plasmodium falciparum antigens from the asexual blood stage was tested. Digestion of the soluble antigens with alpha-D-galactosidase clearly affected the ability of the antigen to react with malaria-immune sera from different geographical origins in crossed immunoelectrophoresis and immunoblotting. Antigens of 220, 180, 80, and 74 kilodaltons were affected by the enzyme treatment. Furthermore, the enzyme digestion reduced the ability of the purified soluble antigen to stimulate lymphocytes from malaria-immune donors. The results might have important implications for the strategy of developing a malaria vaccine.     

Detection of reactive oxygen species (ROS) and apoptosis in human fragmented embryos

In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture environment differs from in-vivo conditions in that the oxygen concentration is higher, and in such conditions the mouse embryos show a higher concentration of reactive oxygen species (ROS) in simple culture media. ROS are believed to cause damage to cell membranes and DNA fragmentation in somatic cells. This study was conducted to ascertain the level of H2O2 concentration within embryos and the morphological features of cell damage induced by H2O2. A total of 62 human oocytes and embryos (31 fragmented, 15 non-fragmented embryos, 16 unfertilized oocytes) was obtained from the IVF-embryo transfer programme. The relative intensity of H2O2 concentrations within embryos was measured using 2',7'-dichlorodihydrofluorescein diacetate by Quanti cell 500 fluorescence imaging and DNA fragmentation was observed with transmission electron microscopy and an in-situ apoptosis detection kit. The H2O2 concentrations were significantly higher in fragmented embryos (72.21 +/- 9.62, mean +/- SEM) compared to non-fragmented embryos (31.30 +/- 3.50, P < 0.05) and unfertilized oocytes (30.75 +/- 2.67, P < 0.05). Apoptosis was observed only in fragmented embryos, and was absent in non-fragmented embryos. Electron microscopic findings confirmed apoptotic bodies and cytoplasmic condensation in the fragmented blastomeres. We conclude that there is a direct relationship between increased H2O2 concentration and apoptosis, and that further studies should be undertaken to confirm these findings.      

Immune response to soluble exoantigens of Plasmodium falciparum may contribute to both pathogenesis and protection in clinical malaria: evidence from a longitudinal, prospective study of semi-immune African children

Some soluble exoantigens of Plasmodium have lipopolysaccharide (LPS)-like properties and are believed to contribute to the pathogenesis of acute malaria. We have studied cellular and humoral immune responses to several purified exoantigens of Plasmodium falciparum in a cohort of children and compared these responses with their subsequent susceptibility to malaria infection and clinical disease. We found no evidence that either lymphoproliferative or interferon-gamma (IFN-gamma) responses to these antigens were associated with protective immunity. On the contrary, children whose cells produced IFN-gamma after in vitro activation with one of the soluble antigens (Ag7) were more likely to experience clinical manifestations of malaria infection (fever and malaise) than were children whose cells did not produce IFN-gamma. It is possible that exoantigen-induced IFN-gamma may exacerbate the LPS-like effects of these antigens. However, serum antibodies to another antigen (Ag2) were more prevalent in children with asymptomatic infections or low parasitemia than in children with fever and higher parasitemia (confirmed clinical malaria), suggesting that these antibodies may contribute to the development of protective immunity.     

Modulation of the cellular immune response during Plasmodium falciparum infections in sickle cell trait individuals.

Plasma and peripheral blood mononuclear cells (PBMC) were obtained from P. falciparum-infected individuals with and without the sickle cell trait at diagnosis and 7 days after treatment. HbAA and HbAS patients were compared for levels of plasma soluble IL-2 receptors (IL-2R) and the in vitro cellular reactivity to affinity-purified soluble P. falciparum antigens (SPAg), PPD and phytohaemagglutinin (PHA). At diagnosis, HbAS patients with clinical disease had lower plasma-soluble IL-2R levels and parasite counts than the corresponding HbAA patients, whereas HbAS and HbAA patients with asymptomatic infections had comparable soluble IL-2R levels and parasite counts. PBMC from HbAS patients had higher proliferation and IFN-gamma production in response to SPAg than PBMC from HbAA patients. The difference in the lymphoproliferative responses to SPAg between the two groups was evident in patients with asymptomatic infections. In all patients, the clinical severity, the soluble IL-2R levels and the parasite counts were directly related. The former two were inversely related to the proliferative responses to SPAg. After treatment, all the studied parameters were comparable in the two groups. The study indicates that during P. falciparum infection, HbAS compared with HbAA patients had lower in vivo cellular activation and higher in vitro cellular reactivity in response to soluble malaria antigens.