Enzymatic changes in polymorphonuclear cells isolated from type II diabetics

Diabetes escalates knee osteoarthritis in rats: Evidence of adaptive mechanism

Clinical reports on the coexistence of diabetes mellitus (DM) and osteoarthritis (OA) dated back to the 1960 s. Therefore, the study investigated the effects of induced DM and/or knee osteoarthritis (KOA) on known biomarkers in male Wistar rats. Twenty rats of five animals per group were induced with DM and/or knee OA using streptozotocin plus nicotinamide and sodium monoiodoacetate. Afterwards, they were left untreated for four weeks.The results showed that pro-inflammatory and pro-oxidative events were most significantly expressed in D + OA group and least in OA group. In contrast to the other experimental groups, there was a decreased bone formation in DM group.Unexpectedly, there were significant increases in bone and cartilage degradation markers in diabetic group, relative to D + OA group. In conclusion, diabetic-osteoarthritic state is characterised by more altered biochemical profile, relative to what is probable in either disease condition. Nevertheless, this situation remains subject to the influence of endogenous homeostatic mechanisms.

Synergistic and non-synergistic effects of salmon calcitonin and omega - 3 fatty acids on antioxidant, anti-inflammatory, and haematological indices in diabetic rats

The optimum therapy for the management of diabetes mellitus (DM) has been a controversial issue. Therefore, the study investigated the effects of salmon calcitonin (Sct) and/or omega-3 fatty acids {eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); EPA/DHA ratio?=?3/2} relative to metformin in diabetic male Wistar rats. Forty rats were used for this study. They were randomly divided into 8 groups of five (5) rats each, which were treated with single or combined administration of salmon calcitonin, N-3 and metformin. DM was induced by the administration of streptozotocin (65?mg/kg b.w., i.p.), 15?min after the administration of nicotinamide (110?mg/kg b.w., i.p.). Nine days afterwards, treatments started, and they lasted for 28 days. Sct was administered at 2.5 and 5.0 IU/kg b.w./day (i.m.), while, N-3 and metformin were administered at 200 and 180?mg/kg b.w./day (p.o.) respectively. The results showed that the induced DM significantly increased pro-inflammatory markers, and significantly altered antioxidant and haematological indices. The combined administration of Sct and N-3 had synergistic effects on total bilirubin and total antioxidant capacity, but, non-synergistic actions on malondialdehyde, uric acid, interleukin-6, lactate dehydrogenase, superoxide dismutase, catalase, glutathione peroxidase, and the haematological parameters. These effects were comparable to that of metformin which showed a more or less therapeutic action than N-3. The study concluded that the antioxidant, anti-inflammatory, and haematological effects of the combined administration of Sct and N-3 is comparable to that of metformin. Nevertheless, the latter showed more or less therapeutic effects relative to N-3.

The measurement of enzyme activities in the resting human polymorphonuclear leukocyte--critical estimate of a method

As a system for study, the isolated human polymorphonuclear leukocyte combines the advantages of a quasi-non-invasive preparation with a nearly complete complement of enzymes of carbohydrate and energy metabolism. However, small sample volumes and, in some cases, very low enzyme activities make high demands on sample processing, storage, and performance of continuous measurements, if the enzyme activities are to be measured with acceptable reproducibility. In the presented study several aspects of homogenization, storage, and continuous measurement were scrutinized, to identify critical steps and consider ways of optimizing the method. Polymorphonuclear leukocytes were separated from the blood of healthy subjects by sedimentation and density gradient centrifugation. After ultrasonic homogenization, 13 enzymes of glycolysis and gluconeogenesis, the tricarboxylic acid cycle, and glycogen metabolism were determined photometrically. The variation of several conditions showed: 1. The duration of exposure to ultrasound for the homogenization of polymorphonuclear leukocytes has no influence over a wide range of time. 2. Addition of the detergents Triton X-100 and deoxycholic acid, as well as the SH-group protector dithiothreitol, to the homogenizing medium increased the measured activities of only a few enzymes. 3. Considerable inaccuracy was encountered when the suspension was divided into parts for homogenization with different additives; such splitting of the suspension should therefore be performed only when necessary, as in the determination of reference values (e.g. protein or DNA content of the cell suspension). 4. Twenty four-fold determination of enzyme activities from one homogenate resulted in precisions between 4.5% (citrate synthase) and 14.4% (transketolase), which is satisfactory for the low activities (as low as 1 U/l) in the homogenate. 5. The reproducibility of enzyme activities, measured in homogenates of polymorphonuclear leukocytes from different blood samples drawn simultaneously, was only slightly worse than that of the continuous measurement method itself. Thus, the precision of the measurement of enzyme activity seems to be the main determinant of the overall method. In conclusion, the described procedure of separation, homogenization, and enzyme measurement in human polymorphonuclear leukocyte meets the requirements of biochemical or clinical trials and can be recommended for clinical metabolic studies.

Kinetics of phosphofructokinase from granulocytes isolated from patients with insulin resistance

Phosphofructokinases from granulocytes isolated from insulin-resistant patients, mainly those from type II diabetics where the degree of insulin resistance was more pronounced, exhibit some changes in their kinetic behavior when assayed under allosteric conditions, characterized by an increased affinity for fructose-6-phosphate, being more resistant to ATP inhibition while it became more sensitive to citrate inhibitory effect. Those changes are suggestive of a isozymic modification to a more L-type enriched enzyme with a loss of the F-type component, probably present in the normal granulocyte.

Kinetic studies of human polymorphonuclear leukocyte phosphofructokinase

Phosphofructokinase from human polymorphonuclear leukocytes has low cooperativity and high affinity for its substrate, F-6-P. It is resistant to ATP inhibition at pH 8; however, at pH 7.1 it becomes sensitive to the effect of this compound. It is activated by F-1, 6-P2; it is not very sensitive to citrate inhibition and F-2, 6-P2 has no effect on its activity. With these kinetic characteristics we assume that perhaps the predominant L-type subunit is accompanied by an F-type component.