Cytosolic adenylate kinase catalyzes the synthesis of thiamin triphosphate from thiamin diphosphate

An attempt was made to purify a porcine skeletal muscle enzyme catalyzing the formation of thiamin triphosphate (TTP) from thiamin diphosphate (TDP), requiring ATP, Mg2+ and a cofactor (creatine). As the purification proceeded, the reaction requirements for ATP and creatine were lost and then a requirement for ADP was manifested. The activity responsible for TTP synthesis from TDP, ADP, and Mg2+ was found to be copurified with adenylate kinase [EC 2.7.4.3] activity, and was finally purified to a single band on SDS-PAGE. Antiserum obtained against the purified enzyme preparation inhibited both adenylate kinase activity and the TTP-synthesizing activity to exactly the same extent. These results indicate that adenylate kinase catalyzes TTP formation from TDP in vitro.     

Comparison of the inhibitions of proliferation of normal and psoriatic fibroblasts by 1 alpha,25-dihydroxyvitamin D3 and synthetic analogues of vitamin D3 with an oxygen atom in their side chain

The inhibitory effects of 1 alpha,25-(OH)2D3 and synthetic oxa-derivatives of vitamin D3 on growth of normal and psoriatic fibroblasts in culture were compared. Proliferation of normal fibroblasts was strongly inhibited by these new compounds in the following order: 22-oxa-1 alpha,25-(OH)2D3 greater than 22-oxa-1 alpha-(OH)D3 greater than 1 alpha,25-(OH)2D3 greater than 20-oxa-1 alpha,25-(OH)2D3. 22-Oxa-1 alpha,25-(OH)2D3 was about 10-times more inhibitory than 1 alpha,25-(OH)2D3. Proliferation of psoriatic fibroblasts was not inhibited by 1 alpha,25-(OH)2D3 at concentrations of up to 10(-6) M, but was suppressed by 10(-8)-10(-6) M 22-oxa-1 alpha,25-(OH)2D3 and 10(-6) M 22-oxa-1 alpha-(OH)D3. These results suggest that oxa-derivatives of vitamin D3, especially 22-oxa-1 alpha,25-(OH)2D3, should be useful in further studies on the cause and treatment of psoriasis.     

Microcalorimetric measurements of tissue cells in vitro

A culture flask was designed for the microcalorimetric measurements of tissue cells by an MS 80 standard calvet microcalorimeter. Tissue cells cultured in this flask behaved in the same manner as in the common culture flask used in cytobiological studies. The thermograms of human adenocarcinoma gastric cells (SGc 7901) and HeLa cells were obtained. The heat output power of SGc 7901 cells continuously increased for 70 h with an initial cell number of 3.0 X 10(5). The thermogram was reproducible under strictly controlled conditions. The relationship between the heat output power and the number of SGc 7901 cells within 48 h was obtained. The heat output power was 40 pW/cell to 49 pW/cell when the cell number was in the range 4.5 X 10(5) to 10.4 X 10(5). It was 62.3 +/- 2.9 pW/cell for HeLa cells when the cell number was 6 X 10(5).     

Scavenging effect of extracts of green tea and natural antioxidants on active oxygen radicals

With the use of the spin trapping methods, the scavenging effects of the extracts of green tea and other natural foods are studied. In stimulated polymorphonuclear leukocytes (PMN) system, water extract fraction 6 (F6) from green tea and green tea polyphenols (GTP) have the strongest scavenging effect on the active oxygen radicals, much stronger than vitamin C (Vc) and vitamin E (VE). Rosemary antioxidants (RA) and Curcumin (Cur) have weaker scavenging effects than Vc, but stronger than VE. In Fenton Reaction, Cur has the strongest scavenging effect (69%) on hydroxyl radicals. In irradiation, riboflavin system F6(74%) and GTP(72%) have very strong scavenging effects that are weaker than Vc, but much stronger than VE (23%). With the use of spin probe oxymetry, the oxygen consumption in respiratory burst of stimulated PMN were measured when the antioxidants existed in these systems. The results demonstrated that these antioxidants did not affect the respiratory burst of human polymorphonuclear leukocytes stimulated with PMA.     

Bombesin microinjected into the dorsal vagal complex inhibits vagally stimulated gastric acid secretion in the rat

Medullary sites of action for bombesin-induced inhibition of gastric acid secretion were investigated in urethane-anesthetized rats with gastric fistula. Unilateral microinjection of bombesin or vehicle into the dorsal vagal complex was performed using a glass micropipet and pressure ejection of 100 nl volume; gastric acid output was measured every 10 min by flushing the stomach. Microinjection of vehicle into the dorsal vagal complex did not alter gastric acid secretion (1.9 +/- mumol/10) from preinjection levels (2.9 +/- 0.8 mumol/10 min). Microinjection of the stable thyrotropin-releasing hormone (TRH) analog, RX 77368, at a 77 pmol dose into the dorsal vagal complex stimulated gastric acid secretion for 100 min with a peak response at 40 min (24.1 +/- 3.2 mumol/10 min). Concomitant microinjection of RX 77368 (77 pmol) with bombesin (0.6-6.2 pmol) into the dorsal vagal complex dose dependently inhibited by 35-86% the gastric acid response to the TRH analog. Bombesin (6.2 pmol) microinjected into the dorsal vagal complex inhibited by 17% pentagastrin infusion-induced stimulation of gastric acid secretion (13.2 +/- 0.8 mumol/10 min) whereas intracisternal injection induced a 69% inhibition of the pentagastrin response. These results demonstrate that the dorsal motor complex is a sensitive site of action for bombesin-induced inhibition of vagally stimulated gastric secretion. However, other medullary sites must be involved in mediating the inhibitory effect of intracisternal bombesin on pentagastrin-stimulated gastric acid secretion.     

Lactose continuous fermentation with cells recycled by ultrafiltration and lactate separation by electrodialysis: model identification

Summary An off-line parameter estimation method has been developed to predict the dynamic behaviour of a continuous lactose fermentation system. The model used is an unstructured model taking into account cell growth, substrate consumption, and metabolite production (lactic acid). This method, based on the Hooke-Jeeves non-linear-programming technique, results in a good estimation of the biological parameters of the model, and so gives a better understanding of the different phenomena involved in lactose fermentation.Nomenclature Cp, Cs, Cz, Dp, Ds, Dz coefficients in system (A) - Fe bioreactor influent flow rate (1/h) - I current in the ED unit (A) - J lactate flux in the ED unit (g/h) - Kd mortality constant (h^-1) - Kp product inhibition constant (g/l) - Ks strbstrate saturation constant (g/l) - P ₀ product concentration in the bioreactor (g/l) - P ₁ product concentration in the D tank (g/l) - P _0r estimation of P ₀ (g/l) - Q ₀ retentate flow rate (UF influent) (1/h) - Q ₁ permeate flow rate (1/h) - Q ₂₂ cell bleed flow rate (1/h) - Q ₃ recycling flow rate in the ED (influent) (1/h) - Se substrate concentration in the influent (g/l) - S ₀ supstrate concentration in the bioreactor (g/l) - S ₁ substrate concentration in tank D (g/l) - S _0r estimation of S ₀ (g/l) - t time (h) - V ₀ fermentation broth volume (1) - V ₁ tank D volume (1) - X ₀ biomass concentration in the bioreactor (g/l) - Y _P/S (=1/Y _S/P) lactic acid yield coefficient (g lactic acid/g lactose consumed) - Y _X/S (=1/Y _S/X) cell yield coefficient (g cells produced/g lactose consumed) - Y _X/Z (=1/Y _Z/X) second cell yield coefficient (g cells produced/g nitrogen consumed) - Y _x, Y _m input mathematical parameters of the linear system (M ₂) - Ze nitrogen concentration in the influent (g/l) - Z ₀ nitrogen concentration in the bioreactor (g/l) - Z ₁ nitrogen concentration in tank D (g/l) - Z _0r estimation of Z ₀ (g/l) - , constants of the Luedeking and Piret's model - specific growth rate (h^-1) - _max maximum specific growth rate (h^-1)     

Calcitonin gene-related peptide (CGRP) in normotensive and spontaneously hypertensive rats

With the techniques of specific radioimmunoassay and gel filtration it was found that CGRP was distributed in various tissues of normotensive (WKY) and spontaneously hypertensive rats (SHR) with the highest concentration in the lumbar spinal cord (1197 +/- 94.8 pg/mg tissue) and the lowest in the auricle (15.0 +/- 2.1 pg/mg tissue). In comparison with WKY, CGRP concentration in the plasma was decreased and in the abdominal aorta and hypothalamus was increased in SHR. Gel filtration revealed only one major CGRP molecular form in the tissues. In addition, CGRP reduced the mean arterial pressure (MAP) in SHR in a dose-dependent manner. These data suggest that CGRP may play an important role in the pathogenesis of hypertension and its possible therapy.     

Discrimination of benign versus malignant mixed tumors of the salivary gland using digital image analysis

Seven benign and four malignant mixed tumors of the salivary gland, biopsied using fine-needle aspiration, were analyzed using digital image analysis. Mean nuclear form factor, perimeter, and area were significantly increased in malignant cases. Better separation between diagnostic categories, however, was achieved by utilizing the coefficient of variation (CV) within a case rather than mean value. Form factor CV alone divided cases into nonoverlapping diagnostic categories. This quantitative analog of "pleomorphism" provided a useful marker for malignancy in mixed tumors.     

IgG from antiserum against endogenous mammalian FMRF-NH2-related peptides augments morphine- and stress-induced analgesia in mice

Two mammalian FMRF-NH2-like peptides have been isolated from bovine brain; an octapeptide with the structure Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2 (F-8-F-NH2) and an octadecapeptide, Ala-Gly-Glu-Gly-Leu-Ser-Ser-Pro-Phe-Trp-Ser-Leu-Ala-Ala-Pro-Gln-Arg-Phe- NH2 (A-18-F-NH2). In the present study determinations were made of the effects of intracerebroventricular administration of IgG prepared from antisera raised against these peptides on nociception and morphine- and immobilization-induced opioid analgesia in mice. Both F-8-F-NH2-IgG and A-18-F-NH2-IgG antisera increased nociception (thermal response latency) and significantly augmented morphine- and immobilization-induced analgesia in a naloxone reversible manner, with F-8-F-NH2-IgG antisera having a greater effect than A-18-F-NH2-IgG antisera. These results provide further evidence that mammalian FMRF-NH2-like peptides function as endogenous opiate antagonists and have a role in the mediation of antinociception.