Staffan Eriksson

Appendectomy versus antibiotic treatment in acute appendicitis. a prospective multicenter randomized controlled trial.

BackgroundAppendectomy has been the treatment for acute appendicitis for over 120 years. Antibiotic treatment has occasionally been used in small uncontrolled studies, instead of operation, but this alternative has never before been tried in a multicenter randomized trial.Patients and MethodsMale patients, 18–50 years of age, admitted to six different hospitals in Sweden between 1996 and 1999 were enrolled in the study. No women were enrolled by decision of the local ethics committee. If appendectomy was planned, patients were asked to participate, and those who agreed were randomized either to surgery or to antibiotic therapy. Patients randomized to surgery were operated on with open surgery or laparoscopically. Those randomized to antibiotic therapy were treated intravenously for 2 days, followed by oral treatment for 10 days. If symptoms did not resolve within 24 hours, an appendectomy was performed. Participants were monitored at the end of 1 week, 6 weeks, and 1 year.ResultsDuring the study period 252 men participated, 124 in the surgery group and 128 in the antibiotic group. The frequency of appendicitis was 97% in the surgery group and 5% had a perforated appendix. The complication rate was 14% in the surgery group. In the antibiotic group 86% improved without surgery; 18 patients were operated on within 24 hours, and the diagnosis of acute appendicitis was confirmed in all but one patient, and he was suffering from terminal ileitis. There were seven patients (5%) with a perforated appendix in this group. The rate of recurrence of symptoms of appendicitis among the 111 patients treated with antibiotics was 14% during the 1-year follow-up.ConclusionsAcute nonperforated appendicitis can be treated successfully with antibiotics. However, there is a risk of recurrence in cases of acute appendicitis, and this risk should be compared with the risk of complications after appendectomy.

Comparison of the substrate specificities of human thymidine kinase 1 and 2 and deoxycytidine kinase toward antiviral and cytostatic nucleoside analogs

Deoxynucleoside kinases are required for the 5-phosphorylation of deoxynucleoside analogs used in chemotherapy. Cytoplasmic thymidine kinase (TK1), deoxycytidine kinase (dCK) and mitochondrial thymidine kinase (TK2) were completely purified from human leukemic spleen and their capacities to phosphorylate 43 nucleoside analogs were compared. TK1 showed the most restricted substrate specificity but tolerated 3-modifications of the sugar ring and some 5-substitutions of the pyrimidine ring. TK2 showed a much broader specificity and phosphorylated pyrimidine bases with bulky 5-substitutions, including cytosine analogs, while sugar analogs with substituents other than OH in the 2 and 3 positions were very poor substrates. dCK showed a very broad specificity phosphorylating several cytosine analogs with 2 and 3 modifications as well as acyclic sugar analogs. Purine deoxyribonucleosides were also efficiently phosphorylated by dCK but in this case sugar modifications led to drastically decreased activity.

BONE MINERAL DENSITY IN PATIENTS WITH PROSTATIC CANCER TREATED WITH ORCHIDECTOMY AND WITH ESTROGENS

Bone mineral density (BMD) and bone mineral content (BMC) were measured in the femoral neck area, trochanteric area and Wards triangle, and in the distal radius of the left forearm before and after 1 year of endocrine treatment in 27 patients with prostatic cancer. Eleven of the patients were treated with orchidectomy and 16 with combined oral and intramuscular estrogens. The patients were free from metastases during the entire observation period. In the orchidectomized patients, BMD and BMC of the distal radius decreased significantly following treatment, whereas no changes were observed in the estrogen-treated patients. These preliminary results demonstrate that estrogens may protect bone in male subjects also and may merit further investigations on larger groups of patients.

Selective assays for thymidine kinase 1 and 2 and deoxycytidine kinase and their activities in extracts from human cells and tissues.

Human cells salvage pyrimidine deoxyribonucleosides via 5-phosphorylation which is also the route of activation of many chemotherapeutically used nucleoside analogs. Key enzymes in this metabolism are the cytosolic thymidine kinase (TK1), the mitochondrial thymidine kinase (TK2) and the cytosolic deoxycytidine kinase (dCK). These enzymes are expressed differently in different tissues and cell cycle phases, and they display overlapping substrate specificities. Thymidine is phosphorylated by both thymidine kinases, and deoxycytidine is phosphorylated by both dCK and TK2. The enzymes also phosphorylate nucleoside analogs with very different efficiencies. Here we present specific radiochemical assays for the three kinase activities utilizing analogs as substrates that are by more than 90 percent phosphorylated solely by one of the kinases; i.e. 3-azido-2,3-dideoxythymidine (AZT) as substrate for TK1, 1-beta-D-arabinofuranosylthymidine (AraT) for TK2 and 2-chlorodeoxyadenosine (CdA) for dCK. We determined the fraction of the total deoxycytidine and thymidine phosphorylating activity that was provided by each of the three enzymes in different human cells and tissues, such as resting and proliferating lymphocytes, lymphocytic cells of leukemia patients (chronic lymphocytic, chronic myeloic and hairy cell leukemia), muscle, brain and gastrointestinal tissue. The detailed knowledge of the pyrimidine deoxyribonucleoside kinase activities and substrate specificities are of importance for studies on chemotherapeutically active nucleoside analogs, and the assays and data presented here should be valuable tools in that research.

Prediction of vertebral strength by dual photon absorptiometry and quantitative computed tomography

SummaryWe measured the lumbar bone mineral of 19 cadavers (10 women, 9 men) by dual photon absorptiometry (DPA) and quantitative computed tomography (QCT). In addition, we determined the ultimate load and stress of each vertebra, and finally ash content and volumetric ash density of the vertebral body. We found that single energy QCT was inferior to DPA and dual energy QCT in the prediction of the ultimate load or stress of vertebrae (P<0.001). The ultimate stress of predicted by using the dual energy QCT results (r=0.71; SEE=36.3 N/cm2) whereas the ultimate vertebral load was best predicted by using the DPA (BMC) results (r=0.80; SEE=740 N). If the QCT finding was multiplied with the surface area of the vertebral body it could be used to predict the ultimate load with good accuracy (r=0.74; SEE=841 N). All the above correlations were higher in women than in men. The frequency of vertebral compression fractures in the material was wel correlated with the bone mineral findings. A nonlinear (third degree) relationship between mineral content and mechanical characteristics is proposed but within the area of measurement used in clinical practice a linear (first degree) equation is preferred.

Expression of deoxycytidine kinase and phosphorylation of 2-chlorodeoxyadenosine in human normal and tumour cells and tissues.

Deoxycytidine kinase (dCK) activates several clinically important drugs, including the recently developed antileukaemic compound 2-chlorodeoxyadenosine (CdA). The distribution of dCK in cells and tissues has previously been determined by activity measurements, which may be unreliable because of the presence of other enzymes with overlapping substrate specificities. Therefore we have measured dCK polypeptide levels in extracts of normal and malignant human peripheral blood mononuclear cells, gastrointestinal tissues and sarcomas, using a specific immunoblotting technique, as well as the phosphorylation of CdA in the same extracts. High levels of dCK were found in all major subpopulations of normal mononuclear leucocytes (120 +/- 19 ng dCK/mg protein) and in B-cell chronic lymphocytic leukaemia (81 +/- 30 ng/mg, n = 23). Hairy-cell leukaemia contained lower levels (28 +/- 23 ng/mg, n = 7), as did three samples of T-cell chronic lymphocytic leukaemia (18 +/- 14 ng/mg). Phytohaemagglutinin stimulation of normal lymphocytes did not lead to any substantial increase in either dCK activity or protein expression (less than 2.5-fold). The human CEM wt T-lymphoblastoid cell line contained 56 +/- 1 ng/dCK/mg protein, while in the CEM ddC50 and AraC8D mutants that lack dCK activity, no dCK polypeptide could be detected. In colon adenocarcinomas, the dCK content was significantly higher (20 +/- 9 ng/mg, n = 20) than in normal colon mucosa (8 +/- 3.5 ng/mg, n = 19, P < 0.05). A similar pattern of dCK expression was found in gastric adenocarcinomas (21 +/- 13 ng/mg, n = 5) and normal stomach mucosa (6 +/- 5 ng/mg, n = 5, P < 0.15). One leiomyosarcoma and one extra-skeletal osteosarcoma showed dCK levels comparable with those found in normal lymphocytes (84 +/- 6 and 109 +/- 4 ng/mg, respectively), while other sarcoma samples contained lower levels, comparable to the gastrointestinal adenocarcinomas (20 +/- 7 ng/mg, n = 12). Thus, dCK is expressed constitutively and predominantly in lymphoid cells, but it is also found in solid non-lymphoid tissues, with increased levels in malignant cells. The phosphorylation of CdA in crude extracts showed a close correlation to the dCK polypeptide level.

ROS-dependent activation of JNK converts p53 into an efficient inhibitor of oncogenes leading to robust apoptosis

Rescue of the p53 tumor suppressor is an attractive cancer therapy approach. However, pharmacologically activated p53 can induce diverse responses ranging from cell death to growth arrest and DNA repair, which limits the efficient application of p53-reactivating drugs in clinic. Elucidation of the molecular mechanisms defining the biological outcome upon p53 activation remains a grand challenge in the p53 field. Here, we report that concurrent pharmacological activation of p53 and inhibition of thioredoxin reductase followed by generation of reactive oxygen species (ROS), result in the synthetic lethality in cancer cells. ROS promote the activation of c-Jun N-terminal kinase (JNK) and DNA damage response, which establishes a positive feedback loop with p53. This converts the p53-induced growth arrest/senescence to apoptosis. We identified several survival oncogenes inhibited by p53 in JNK-dependent manner, including Mcl1, PI3K, eIF4E, as well as p53 inhibitors Wip1 and MdmX. Further, we show that Wip1 is one of the crucial executors downstream of JNK whose ablation confers the enhanced and sustained p53 transcriptional response contributing to cell death. Our study provides novel insights for manipulating p53 response in a controlled way. Further, our results may enable new pharmacological strategy to exploit abnormally high ROS level, often linked with higher aggressiveness in cancer, to selectively kill cancer cells upon pharmacological reactivation of p53.

The Incidence of Clinical Postoperative Thrombosis After Gastric Surgery for Obesity During 16 Years

Background: Suggested risk factors for postoperative thrombosis such as high fatty acid levels, hypercholesterolemia and diabetes are common in obese patients. Methods: In a retrospective study, the case records of 328 patients operated for obesity by gastric procedure from September 1977 until December 1993 were analyzed: 253 women and 75 men with a mean age of 38 years and a mean body mass index (BMI) of 44 kg/m2. The operation time, use of epidural anesthesia, and the occurrence of risk factors; fatty acid levels, hypercholesterolemia and diabetes were recorded. Symptomatic thromboses were verified by phlebography or phylethysmography and pulmonary embolism with ventilation/perfusion scintigraphy or autopsy. Results: The mean operating time was 128 minutes, 77% had epidural anesthesia and the mean hospital stay was 12.3 days. The long hospital stay was due to the fact that most patients took part in different scientific studies perioperatively. The incidence of thromboembolism was 2.4%. Four patients ad pulmonary embolism, in one of them this was fatal. Three patients had deep leg vein thrombosis and one patient had arm thrombosis secondary to a central venous catheter. None of these patients had high fatty acids, catheter. None of these patients had high fatty acids, diabetes or high cholesterol. Of the patients, 298 were given dextran-70 (Macrodex®, Pharmacia) as prophylaxis, seven were given heparin and 23 were given no prophylaxis. In the patient group without diagnosed thrombosis, 31% had high fatty acid levels, 2% had high cholesterol levels and 9% had diabetes. Conclusions: Obese patients seem to have a moderate risk of developing postoperative thrombosis when an effective prophylaxis is used. High free fatty acids, hypercholesterolemia and diabetes are not obvious extra risk factors in obese patients. Thromboprophylaxis should be given to all operated obesity patients regardless of age. The surgeons must be aware and investigate promptly any symptoms suggestive of thromboembolism.

[30] Ribonucleoside diphosphate reductase (Escherichia coli)

Publisher Summary This chapter describes the assay methodology of ribonucleoside diphosphate reductase. Ribonucleotide reductase from E. coli consists of two nonidentical subunits––proteins B1 and B2––that have no biological activity when assayed separately. Deoxyribonucleotides are synthesized by a direct reduction of the corresponding ribonucleotides. The reaction is catalyzed by ribonucleotide reductase that in this way is involved in the control of DNA synthesis. The enzyme is purified to homogeneity and studied extensively in Escherichia coli and Lactobacillus leichmannii . An E. coli strain that is lysogenic for a defective lambda carrying the genes of ribonucleotide reductase overproduces the enzyme upon induction. The preparation of large amounts of homogeneous enzyme rests on the use of this source containing 10% of the total protein as ribonucleotide reductase.

Deoxycytidine kinase is constitutively expressed in human lymphocytes: Consequences for compartmentation effects, unscheduled dna synthesis, and viral replication in resting cells

Deoxycytidine kinase specific activity was high in human peripheral lymphocytes and increased less than 2-fold when the lymphocytes were stimulated by phytohemagglutinin A. Ion-exchange chromatography showed the same profile of deoxycytidine kinase activity in resting and proliferating cells. This enzyme could also efficiently phosphorylate deoxyadenosine and deoxyguanosine. In contrast, the thymidine kinase activity was very low in resting peripheral lymphocytes and increased more than 40-fold upon stimulation. Similar relative changes in the activities of the two enzymes were observed in human T-lymphoblast cells (CCRF-CEM) separated by centrifugal elutriation into cells of different cell cycle phases. The ratio of deoxycytidine to thymidine kinase activities is 20:1 in extracts from resting human lymphocytes and 1:2 in PHA-stimulated cells. This drastic change in deoxyribonucleoside phosphorylating activities during the cell cycle in human lymphocytes is of importance for studies on unscheduled DNA synthesis, for the design of therapies to interfere with viral DNA metabolism, and for a correct interpretation of the compartmentation effects observed in DNA precursor metabolism.