Magne Aas

Organ and subcellular distribution of fatty acid activating enzymes in the rat

Abstract 1. 1. The organ and subcellular distribution of ATP-dependent fatty acid activating enzymes have been studied in rat. 2. 2. Our results when correlated with earlier studies on isolated enzymes suggest the existence of five different ATP-dependent acyl-CoA synthetases (I–V) with chain length optima at C2, C4, C7, C12 and C16, respectively. 3. 3. All tissues studied apparently contain Enzymes IV and V while some tissues lack one or more of the Enzymes I–III. Liver, kidney and heart muscle apparently contain all five enzymes. Skeletal muscle and epididymal fat seem to contain only the two long-chain activating enzymes. 4. 4. The subcellular distribution of fatty acid activating enzymes seems to be principally the same in all tissues. Short-chain fatty acids (Enzymes I–III) are activated in the mitochondrial matrix, long-chain fatty acids (Enzymes IV, V) in the outer membrane of the mitochondria and in the microsomes. The medium-chain acids are activated in all three places because of the overlapping in enzyme specificity. 5. 5. The studies gave no conclusive evidence for fatty acid activation in the inner membrane of the mitochondria.

Short-chain fatty acid activation in rat liver. A new assay procedure for the enzymes and studies on their intracellular localization.

Abstract 1. 1. Acetyl-CoA synthetase (acetate:CoA ligase (AMP), EC 6.2.1.1) and mediumchain acyl-CoA synthetase (acid: CoAligase (AMP), EC 6.2.1.2) have been studied in rat-liver homogenate and cellular subfractions. A new assay procedure for the enzymes has been worked out. The acyl-CoA formed is transformed into acylcarnitine by excess amounts of acetyl-CoA: carnitine acetyl transferase (EC 2.3.1.7) in the presence of radioactive carnitine. 2. 2. With differential centrifugation of rat-liver homogenate, it has been shown that the medium-chain acyl-CoA synthetase is exclusively localized in mitochondria, and by subfractionation of the mitochondria we found that the enzyme is confined to the matrix. 3. 3. The acetyl-CoA synthetase apparently has a bimodal intracellular localization, the enzyme being localized both in mitochondria and in the particle-free supernatant. The mitochondrial part is confined to the matrix.

Randomized trial comparing cisplatin with radioactive phosphorus or whole-abdomen irradiation as adjuvant treatment of ovarian cancer

In this study, 347 patients with epithelial ovarian cancer without residual tumor after primary laparotomy, were assigned randomly to receive either intraperitoneal instillation of radioactive phosphorus (32P) or six courses of cisplatin (50 mg/m2. Patients randomized to receive 32P with extensive intraperitoneal adhesions were treated with whole‐abdomen irradiation instead of 32P (n = 28). The median follow‐up was 62 months. Crude and disease‐free survival were similar in all groups. Late bowel complications occurred more often in patients treated with 32P compared with the cisplatin group. The estimated 5‐year crude survival rate was as high as 95% in patients with borderline or well‐differentiated tumors in Stage I. It is suggested that these patients can be treated adequately by operation alone. Patients with moderately or poorly differentiated cancers in Stage I disease had a 5‐year crude survival rate of 75%. In these patients, the relapse risk was high enough to warrant postoperative treatment. The efficacy of adjuvant treatment in this subgroup of patients can only be established in a prospective randomized study comparing postoperative adjuvant treatment with a no‐treatment arm. Because of the high number of late bowel complications after 32P treatment, it was recommended that cisplatin be used as standard adjuvant treatment for subsequent controlled studies.

Lymph drainage from the vulva

Fifty-four patients with cervical cancer stage Ib were injected preoperatively with 99mTc-colloid in different areas of the vulva and three controls in the axilla. The radioactivity in the groins and the pelvis was measured with a scintillation camera and in the removed pelvic lymph nodes with a well counter. A low activity could be measured in the removed pelvic nodes of the controls indicating the radioactivity which had reached the pelvic nodes via the bloodstream. Clitoris and perineum had a bilateral lymph flow. In all the other patients the vast majority of the radioactivity was found in the ipsilateral lymph nodes. A significant, but small amount of activity was recorded in the contralateral nodes in 67% of the patients and in all patients injected in the anterior part of the labium minus. The medial external iliac lymph chain had an uptake of 73% of the total activity measured in the removed pelvic nodes. Only in 13% of the patients was the activity higher in the lateral than in the medial external iliac chain. Direct lymphatic pathway from the clitoris to the pelvic lymph nodes was not found. Anastomoses exist probably in 13 out of 42 patients between the presacral and/or common iliac nodes on both sides.

Fatty acid activation and acyl transfer in organs from rats in different nutritional states

Abstract 1. 1. The activities of the fatty acid activating enzymes, carnitine palmityltransferase and glycerophosphate acylating enzyme(s) have been measured in the liver, heart, and epididymal fat from fed, fasted, glucose-refed, and fat-fed rats. 2. 2. Fasting gave no significant change in the activation of long-chain fatty acids, but glucose-refeeding caused a decreased activation rate in the liver. 3. 3. The activation of short- and medium-chain fatty acids was reduced during fasting in all the investigated organs. Glucose-refeeding increased the activation of heptanoate in the liver and all the short- and medium-chain acids in heart. 4. 4. The carnitine palmityltransferase activity in the liver increased both in fasted and fat-fed animals. Glucose-refeeding normalized the activity. No significant changes were found in the other tissues. 5. 5. The glycerophosphate acylation in the liver and heart decreased during fasting and fat-feeding. After glucose-refeeding the activity in the liver increased again to the level found in the controls. 6. 6. It is suggested that in rat liver the activity of the fatty acid-activating enzymes, the carnitine palmityltransferase and the glycerophosphate acylating enzyme(s) participate in the regulation of fatty acid metabolism. The study gives no conclusive evidence for such mechanisms in the heart or epididymal fat.

Role of strontium-89 as adjuvant to palliative external beam radiotherapy is questionable: Results of a double-blind randomized study

PURPOSE To explore the efficacy of adjuvant (89)Sr applied with external beam radiotherapy (EBRT) to treat bone metastases. METHODS AND MATERIALS Ninety-five patients were randomized to (89)Sr (Arm A) or saline (Arm B) on Day 1 of EBRT to demonstrate a reduction in 3-month physician-assessed subjective progression from 70% to 45%. RESULTS At 3 and 6 months, no difference between treatment arms was observed in the progression rate. At 3 months, the physician-assessed response rate for all patients was 25%, with 46% of the patients progressing. The pretreatment use of opiates was independently associated with short progression-free survival. On the basis of the quality-of-life assessments, pain relief occurred in 50% of patients and 32% experienced improvement in global quality of life, without impact from (89)Sr. Differences were observed between the physician evaluation of radiotherapy efficacy and the patient assessment. In Arm A, serum alkaline phosphatase, but not serum prostate-specific antigen, decreased during the first 3 months after treatment. CONCLUSION (89)Sr, adjuvant to ERBT, does not seem to reduce the number of patients with subjective progression at 3 months. Patients should be referred for palliative RT before their bone pain requires high doses of opiates. In radiotherapy trials, the evaluation of pain and pain relief remains problematic because of the confounding use of analgesics.

The activity of the different carnitine acyltransferases in the liver of clofibrate-fed rats.

Abstract 1. 1. Rats were fed 0.3% clofibrate in the stock diet for one and two weeks. 2. 2. Clofibrate caused a variable increase in carnitine acyltransferase activities in the liver dependent on the chain length of the substrates. The following factors for the increase in specific activity were observed: 5.3 (short-chain acyltransferase), 2.8 (medium-chain transferase), and 1·7 (long-chain transferase). 3. 3. These results support our earlier conclusion (H.E. Solberg, FEBS Lett., 12 (1971) 134) that a carnitine medium-chain acyltransferase exists. 4. 4. Clofibrate also caused a small increase in short-chain and medium-chain acyl-CoA hydrolase activity.

Targeted Radiotherapy of Osteosarcoma Using 153Sm-Edtmp: A new promising approach

We report a case where targeted radionuclide therapy using 153Sm-EDTMP gave substantial palliative effect. A 35-year-old male with a primary osteosarcoma located in the first lumbar vertebra relapsed with progressive back pain after conventional treatment modalities had failed. He became bedridden, and developed paraparesis and impaired bladder function. On a diagnostic bone-scan intense radioactivity was localized in the tumor. He therefore was given 153Sm-EDTMP treatment twice, 8 weeks apart, 35 and 32 MBq/kg body weight respectively. After a few days the pain was significantly relieved and by the second radionuclide treatment the pareses subsided. For six months he was able to be up and about without any neurological signs or detectable metastases. Eventually, however, he experienced increasing local pain, developed paraparesis, was re-operated but died 4 months later. The dramatic transient improvement observed in this case warrants further exploration using 153Sm-EDTMP as a boost technique, supplementary to conventional external radiotherapy.

89Strontium in bone metastases from hormone resistant prostate cancer: palliation effect and biochemical changes.

Hematological and biochemical parameters were evaluated in 31 patients receiving 150 MBq 89Strontium (89Sr) intravenously due to painful skeletal metastases from hormone resistant prostate cancer. Two and 3 months after the injection prostate specific antigen (PSA) had increased by a median of 36% and 100%, respectively, as compared to the pretreatment value whereas alkaline phosphatase (APHOS) had decreased by about 20% (median). The leucocyte and platelet counts were reduced by about 20-35%, without reaching grade greater than or equal to 2 toxicity. Pain relief was reported in 14 of 29 evaluable patients at 2 months and in 11 of 23 patients at 3 months. It is concluded that 89Sr represents a worthwhile therapeutic modality in the palliation treatment of patients with hormone resistant prostate cancer, though the biological significance of frequently increasing PSA and decreasing APHOS is not yet completely understood.

Long-chain acyl-Coa synthetase in rat liver stimulation by high salt concentrations

Abstract 1. 1. The microsomal long-chain acyl-CoA synthetase (acid: CoA ligase (AMP), EC 6.2.1.3) from rat liver was stimulated by high concentrations of salts. 2. 2. This stimulation has been compared with the stimulation obtained with the protein factor present in particle-free supernatant 1 . Both the supernatant factor and high concentrations of salts increased the V max of the reaction. 3. 3. The presence of salts reduced the effect of the supernatant factor. 4. 4. High concentrations of ATP strongly inhibited the effect of the supernatant factor while no significant influence of excess ATP was observed when the acyl-CoA synthetase was stimulated by salts. 5. 5. Both the stimulated and the unstimulated long-chain acyl-CoA synthetase were strongly inhibited by palmityl-CoA. 6. 6. The stimulating supernatant factor was purified 7 times by (NH 4 ) 2 SO 4 -precipitation and calcium phosphate gel adsorption.