Microsurgery in the diabetic foot

The treatment of serious tissue defects on the diabetic foot is complicated and tedious because of a combination of pathogenetic mechanisms that influence healing. Diabetic neuropathies (sensory, motor, vegetative), ischaemia and microangiopathies contribute in varying degrees to the adverse healing. The submitted three-year prospective study was focused on an analysis of the pathogenetic factors with the objective of defining the indications for one of three types of microsurgical transfer: 1. a free flap sutured directly to the vessels at the site of the defect (in predominantly neuropathic defects); 2. a free flap sutured to a politeopedal bypass (in predominantly ischaemic defects); 3. a "nourishing" flap sutured by means of a long venous graft to vessels of the medial and upper leg (in patients in whom an inadequate outflow tract does not make revascularisation possible). In the first year of the investigation, thirteen patients were operated on by means of a free muscle flap incl. three "nourishing" and ten sutured at the site of the defect. Twelve flaps were flaped healed; one patient died from myocardial infarction on the second day after surgery.     

Inhibited growth of colon cancer carcinomatosis by antibodies to vascular endothelial and epidermal growth factor receptors

Vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) regulate colon cancer growth and metastasis. Previous studies utilizing antibodies against the VEGF receptor (DC101) or EGF receptor (C225) have demonstrated independently that these agents can inhibit tumour growth and induce apoptosis in colon cancer in in vivo and in vitro systems. We hypothesized that simultaneous blockade of the VEGF and EGF receptors would enhance the therapy of colon cancer in a mouse model of peritoneal carcinomatosis. Nude mice were given intraperitoneal injection of KM12L4 human colon cancer cells to generate peritoneal metastases. Mice were then randomized into one of four treatment groups: control, anti-VEGFR (DC101), anti-EGFR (C225), or DC101 and C225. Relative to the control group, treatment with DC101 or with DC101+C225 decreased tumour vascularity, growth, proliferation, formation of ascites and increased apoptosis of both tumour cells and endothelial cells. Although C225 therapy did not change any of the above parameters, C225 combined with DC101 led to a significant decrease in tumour vascularity and increases in tumour cell and endothelial cell apoptosis (vs the DC101 group). These findings suggest that DC101 inhibits angiogenesis, endothelial cell survival, and VEGF-mediated ascites formation in a murine model of colon cancer carcinomatosis. The addition of C225 to DC101 appears to lead to a further decrease in angiogenesis and ascites formation. Combination anti-VEGF and anti-EGFR therapy may represent a novel therapeutic strategy for the management of colon peritoneal carcinomatosis.     

Tyrosine kinase inhibition of multiple angiogenic growth factor receptors improves survival in mice bearing colon cancer liver metastases by inhibition of endothelial cell survival mechanisms

Redundant mechanisms mediate colon cancer angiogenesis. Targeting multiple angiogenic factors simultaneously may improve survival of mice with colon cancer metastases. BALB/c mice underwent splenic injection with CT-26 colon cancer cells to generate liver metastases and received administration of either vehicle alone or a tyrosine kinase inhibitor for vascular endothelial growth factor, basic fibroblast growth factor, and platelet-derived growth factor receptors (SU6668). Mice were sacrificed when they became moribund as determined by a blinded observer. In a parallel experiment, groups of mice were sacrificed at earlier time points to better define the kinetics of the effect of SU6668 on angiogenic parameters over time. SU6668 increased median survival by 58% (P < 0.001) and led to a progressive increase in tumor cell and endothelial cell apoptosis that increased over time. In addition, pericyte vessel coverage and tumor vascularity were significantly decreased in mice treated with SU6668. Based on current knowledge of endothelial cell survival, these data suggest that SU6668 may prevent tumor endothelial cell survival directly (vascular endothelial growth factor) and indirectly (pericyte coverage) by affecting endothelial cell survival mechanisms.     

Results of experimental implantation of microvascular prostheses in three recipient animal species

A total of 286 knitted vascular prostheses made of polyethylene terephthalate and surface-treated with polyurethane, polylactide, or both were implanted over the past 6 years. Of this total number, 224 prostheses were implanted in rats, nine in dogs, and 53 in pigs. We developed 39 types of knitted prostheses. The best results were obtained with prosthesis no. 36, which was surface-treated with polyurethane and polylactide. Prostheses 10 mm in length with a diameter of 2 mm implanted into rat aortas showed 100% patency during the observation periods of 2 months (ten implants) and 1 year (40 implants). Although various antithrombotic treatment schemes were tested, implantations of 5-cm- to 10-cm-long no. 36 prostheses in dogs were unsuccessful. The results of implantation of 3-mm caliber no. 36 prostheses to pigs were comparable with those obtained with Gore-Tex prostheses. Intensive antithrombotic treatment with heparin and Rheomacrodex intraoperatively followed by Fraxiparine (0.3 ml/12 h), was necessary to ensure early patency of the implants. Lower dosage of antithrombotic drugs resulted in transient incomplete occlusion of the implant. Full patency resumed after 1 month.     

Genetic testing and prevention of hereditary cancer at the MMCI--over 10 years of experience

Hereditary cancer syndromes are frequently seen in young cancer patients and patients with a positive family history. Genetic testing is important for the identification of high-risk individuals, and for the early introduction of specialized preventive care or prophylactic surgeries. High-risk tumour suppressor genes (BRCA1 and BRCA2) and DNA repair genes (MLH1, MSH2 and MSH6) are responsible for a substantial part of hereditary breast, ovarian and colorectal cancer. Other hereditary cancers are seen less frequently, but genetic testing has increased for many other site-specific cancers and complex syndromes. Genetic centres and molecular genetic laboratories are located mostly within university or regional hospitals. Some genetic centres are private. It is highly recommended (Czech Society for Medical Genetics) that all laboratories are accredited according to ISO 15,189 and that genetic testing of hereditary cancer syndromes is indicated by medical geneticists. The indication criteria and prevention strategies were published in Supplement 22 of Clinical Oncology 2009 (in Czech). Preventive care for high-risk individuals is organized by thirteen Oncology Centres, which provide most of the oncology care in the Czech Republic. Genetic testing and preventive care for high-risk individuals and mutation carriers is covered by health insurance. The molecular genetic laboratory at the MMCI provides molecular genetic testing of BRCA1, BRCA2, CHEK2 for hereditary breast/ovarian cancer, MLH1, MSH2, MSH6 for Lynch syndrome,TP53 for Li-Fraumeni syndrome, CDKN2A for familial malignant melanoma syndrome and CDH1 gene for hereditary diffuse gastric cancer. Other syndromes are tested in specialized laboratories elsewhere.The use of genetic testing is increasing because of more frequent referrals from oncologists and other specialists and the increasing variety of genes tested. However, in some patients the testing is not recommended and other family members are dying because of the late diagnosis of hereditary syndrome. Greater awareness of the importance of genetic testing in oncology is needed.     

The association of the decline in glomerular filtration rate with aggressive endometrial cancers

International Urology and Nephrology - Most site-specific cancer incidence is increased with the decrease of glomerular filtration rate (GFR). We analyzed endometrial cancers depending on different...     

Portosystemic shunt versus orthotopic liver transplantation for the Budd-Chiari syndrome.

We have analyzed the indications and results of shunt operation versus orthotopic liver transplantation (OLT) in 22 patients with Budd-Chiari syndrome (BCS). The underlying cause of the syndrome was similar between the two groups and was related to myeloproliferative disorders or the use of birth control pills in 18 of 22 patients. The results of biopsies of the liver showed centrilobular congestion and necrosis in all candidates who underwent shunting and the presence of fibrosis and cirrhosis in the OLT candidates. The indications for shunts included symptoms related to portal hypertension only and well-preserved synthetic hepatic function. Ten patients were treated with 12 shunt procedures, including mesoatrial (eight patients) and side to side portacaval shunt (four patients). Significant complications after shunt procedure included fulminant (one of ten patients) and progressive (one of ten patients) hepatic failure requiring urgent OLT; one death occurred because of pulmonary sepsis. Indications for OLT were signs of end stage liver expressed by severe portal hypertension and variceal bleeding (four of 14 patients), progressive encephalopathy (seven of 14 patients) and poor synthetic function (bilirubin greater than 3 milligrams per deciliter in eight of 14 patients and albumin less than 3.0 grams per liter, or both, in ten of 14 patients). Fourteen patients were treated with 16 OLT, three patients had retransplantation for primary nonfunction graft (two of 14 patients) or chronic rejection (one of 14 patients). There were two early deaths in the group. With a follow-up period between two months to five years, 12 of 14 patients undergoing OLT are alive, fully functional and have normal liver function tests. Seven of ten patients who had shunts are alive, six are able to maintain normal activity and one has progressive end stage hepatic disease and is not a candidate for OLT. However, the hepatic function continues progressively to be abnormal. Various options are available for the treatment of the syndrome. Portosystemic decompression is effective and should be considered at the early stage of the disease, prior to the development of significant hepatic failure. However, few of the patients will continue to have slow, but progressive hepatic failure and may require OLT. The only effective treatment for end stage hepatic disease secondary to the BCS is OLT.     

A simple model to estimate survival after retransplantation of the liver

To formulate a model predicting survival after liver retransplantation, we analyzed in detail the last 150 cases of hepatic retransplantation at UCLA. Cox proportional hazards regression analysis identified five variables that demonstrated independent simultaneous prognostic value in estimating patient survival after retransplantation: (1) age group (pediatric or adult), (2) recipient requiring preoperative mechanical ventilation, (3) donor organ cold ischemia > or =12 hr, (4) preoperative serum creatinine, and (5) preoperative serum total bilirubin. The Cox regression equation that predicts survival based on these covariates was simplified by assigning individual patients a risk classification based on a 5-point scoring system. We demonstrate that this system can be employed to identify a subgroup of patients in which the expected outcome is too poor to justify retransplantation. These findings may assist in the rational selection of patients suitable for retransplantation.     

Methylene blue but not changes in cyclic GMP inhibits resting and bradykinin-stimulated production of prostacyclin by pig aortic endothelial cells.

1. Primary cultures of pig aortic endothelial cells produced 6-keto-prostaglandin F1 alpha (6-keto PGF1 alpha), the stable breakdown product of prostacyclin, both in the resting state and in response to bradykinin. The rise in 6-keto-PGF1 alpha production induced by bradykinin (1-100 nM) was concentration-dependent. 2. Treating endothelial cells with the inhibitor of soluble guanylate cyclase, methylene blue (0.1-20 microM) produced an irreversible reduction in resting and bradykinin (0.1 microM)-stimulated production of 6-keto-PGF1 alpha with an IC50 of 0.5 +/- 0.1 microM. Treating endothelial cells with haemoglobin (10 microM) had no effect on resting or bradykinin (0.1 microM)-stimulated production of 6-keto-PGF1 alpha. 3. Two stimuli that elevate the level of guanosine 3':5'-cyclic monophosphate (cyclic GMP) in endothelial cells, 8-bromo cyclic GMP (30 microM) and atriopeptin II (0.1 microM), each had no effect on resting or bradykinin (0.1 microM)-stimulated production of 6-keto-PGF1 alpha. Furthermore, treating endothelial cells with either 8-bromo cyclic GMP (30 microM) or atriopeptin II (0.1 microM) had no effect on the ability of methylene blue (20 microM) to inhibit resting or bradykinin (0.1 microM)-stimulated production of 6-keto-PGF1 alpha. 4. Adding arachidonic acid (1 microM) to endothelial cells led to a marked stimulation of 6-keto-PGF1 alpha production. Treating cells with either methylene blue (20 microM) or the cyclo-oxygenase inhibitor, flurbiprofen (10 microM), inhibited both resting and arachidonic acid (1 microM)-induced production of 6-keto-PGF1 alpha.(ABSTRACT TRUNCATED AT 250 WORDS)