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Genetic and kinetic evidence is presented to show that the carrier-mediated uptake of the anionic sugars 3-deoxy-2-oxo-D-gluconate and D-glucuronate by Escherichia coli involves the concomitant transport of protons.
A preparation containing an iron-poly(sorbitol-gluconic acid) complex for parenteral treatment of iron deficiency anaemia is described. The physical and chemical properties of the iron complex have been studied by using electrophoresis and gel permeation chromatography. A rapid absorption from the injection site after intramuscular administration to rabbits takes place, 70% of the iron being absorbed after 24-48 hours. Thereafter, the absorption rate is slower, and 32 days after the injection 94% has been absorbed from the injection site. In rabbits the maximum level of iron in serum is reached after 12-24 hours; in dogs after 1-3 hours. Disappearance from the serum takes place slowly. The complex is exclusively absorbed via the lymphatic route. Nine to ten per cent of the given dose is excreted by the kidney within 72 hours in rats and 24 hours in rabbits after intramuscular administration. On administration of the preparation to rats, made anaemic by phlebotomy, a rapid increase of haemoglobin values is observed as well as a very high utilization of the retained amount of the given dose.
Intravenous injection of the iron-poly(sorbitol-gluconic acid) complex (IPSG) to cats anaesthetized with sodium pentobarbitone caused a transient decrease in mean arterial blood pressure and a temporary increase in central venous pressure, heart rate and femoral blood flow at large doses (cumulative doses up to 744 mg/kg). Tachyphylaxis developed upon repeated administration. A temporary reduction in the magnitude of the blood pressure responses to noradrenaline and isoprenaline was obtained after large doses of IPSG. The blood pressure effects of acetylcholine, histamine and bilateral carotid occlusion were not affected. No definite effects were seen on the electrocardiograms. The transient cardiovascular effects were interpreted as being due to the presence of small amounts of ferrous iron in the preparation. IPSG did not significantly affect blood coagulation or platelet aggregation as judged from results of in vitro and in vivo experiments. Immunogenicity studies in rabbits and antibody analyses of sera from patients treated with IPSG failed to demonstrate any effect of IPSG on the immune system.
The possible influence of Ferastral, an iron-poly(sorbitol-gluconic acid) complex, on blood coagulation in man was investigated. Ferastral added to plasma produced no changes in blood coagulation until a final concentration of 2 000 microgram/ml (35.8 mmol/1) was used, when minimal changes in blood coagulation factors were observed. Five patients were given an intramuscular injection of 250 mg Ferastral. No changes in blood coagulation and thrombocyte function were observed up to 5 hours after the initial iron injection.
Four groups of Sprague-Dawley rats were given Ferastral, an iron-poly(sorbitol-gluconic acid) complex (IPSG) or Imferon, an iron-dextran complex, intramuscularly twice a week for 17 weeks. The experiment lasted for 95 weeks. Each compound was given to two groups, one low dose group and one high dose group. Depending on the body mass, the dose levels varied between 2.5 and 10 mg (25-50 mg/kg body mass) and between 5 and 20 mg (50-100 mg/kg body mass) of iron per rat, respectively. The mean total dose of iron per rat was calculated to be 235 and 495 mg, respectively. Another group of animals served as a control. From about the 30th experimental week onwards tumours developed at the intramuscular injection sites in the groups given Ferastral and Imferon. The tumours appeared to be sarcomas. In almost all the treated animals that lived longer than 30 weeks after the start of the experiment, sarcomas were present at the intramuscular injection sites. The sarcomas appeared earlier in the high dose groups than in the low dose groups and slightly earlier in the rats given Ferastral than in those given Imferon. No other pathological changes, including neoplasms, were considered to be related to the treatment.
An iron carbohydrate complex, iron-poly(sorbitol-gluconic acid), Ferastral, was labelled with 59Fe, and its distribution in rats was studied. The animals were intramuscularly treated with a dose of 10 mg of iron/kg. Three groups of animals were used: group A: non-anaemic and group B: anaemic rats, both kept on iron-deficient diet, and group C: non-anaemic rats kept on iron-supplemented diet. Urinary and faecal excretion, distribution in the body and incorporation in blood of the 59Fe was followed up to 28 days. The total excretion after that time was 15%. There was a rapid initial phase followed by a slower continuous one. After 28 days group A had 25, group B 13 and group C 40% of the given dose remaining at the site of injection. The corresponding values in liver after 28 days were 7, 4 and 17% of the given dose, respectively. In blood a continuous increase was observed. At 28 days after administration 26, 43 and 17% of the given dose had been incorporated in the red blood corpuscles of the respective groups. These results show that the iron complex is absorbed from the site of injection and is utilized for haemoglobin synthesis. They also show that the disposition of the complex is influenced by the iron content of the diet.
The local and systemic availability of the iron in an iron-poly(sorbitol-gluconic acid) complex (Ferastral) has been studied in rats. The animals were treated intramuscularly with the complex in a dose corresponding to 10 mg of iron per animal. The technique of repeated phlebotomy was used to induce and maintain constant levels of anaemia. The phlebotomies were started immediately after injection and at 14 and 28 days after dosing. At the end of the appropriate interval, the remaining amount of iron at the injection sites as well as the degree of utilization of the iron retained in the animals were estimated. It was shown that the amount of iron at the site of injection of these anaemic animals was less than 3% regardless of the time when the series of phlebotomies were started. It was also shown that the degree of utilization of the iron from the complex was 90% of the retained amount of iron when the phlebotomies immediately followed dosing, and 86% and 79% when initiated 14 days and 28 days respectively. The significance of the decrease in utilization is discussed.
The metabolism of iron-poly (sorbitol-gluconic acid) complex (Ferastral) was studied in 6 blood donors with latent iron deficiency and 13 patients with manifest iron deficiency anaemia. Between 125 and 1 000 mg of iron were injected. In latent deficiency an average of 19% of the dose given was excreted during the first two weeks. The corresponding figure for patients with manifest iron deficiency was 11%. An average of 8% of the dose was retained at the site of injection after 40 days. In the two groups, respectively, 61% (range 47%-70%) and 58% (range 24%-86%) of the iron retained was incorporated into red cells after 40 days, which is judged to be quite satisfactory. Some local side effects were observed.
An iron-poly (sorbitol-gluconic acid) complex (Ferastral) labelled with 59Fe was administered by intramuscular injection to clinically and haematologically normal male volunteers. Urinary excretion of radioactivity was measured for the first 48 hours following injection, and was 2%-10% of the administered dose. Disappearance of radioactivity at the site of injection and accumulation of radioactivity in the liver, spleen, and sacrum were measured by external scintillation counting. Plasma radioactivity was measured at intervals for four days and red cell incorporation of 59Fe reached levels of 29%-57.5%. An unexpected finding was that the highest levels of urinary excretion of radioactivity did not coincide with the highest levels of plasma radioactivity.
The characteristics of iron stores built up by a new parenteral iron-poly (sorbitol-gluconic acid) complex, Ferastral, have been studied in iron depleted non-anemic blood donors. The results from studies on the first three subjects are presented. The availability of this storage iron for the chelator, desferrioxamine, was found to be in the same range as normal iron stores. The pattern of distribution in reticulo-endothelial cells of the bone marrow could not be differentiated from natural storage iron. No visible iron could be detected in liver parenchymal cells 40 days after iron administration. The results from these preliminary studies suggests normal bioavailability of this material for Hb-synthesis. The absence of iron in liver parenchymal cells might be explained by the short time interval between the iron administration and the fine needle aspiration biopsy.
A new iron-poly (sorbitol-gluconic acid) complex (Ferastral) has been studied. A method of assay is described. The iron complex may be separated from serum transferrin using a Sephadex DEAE A50 column. This binds the iron complex and elutes iron-transferrin which can then be assayed. It is shown that the assay of serum transferrin unsaturated binding capacity using excess 59FeCl2 and MgCO3 adsorption, is valid in the presence of Ferastral. Serum unsaturated iron binding capacity may therefore be used to follow the binding of Ferastral iron by transferrin. These methods may be used to follow the distribution of iron in plasma after an intramuscular injection of Ferastral.
A clinical investigation of an iron-poly (sorbitol-gluconic acid) complex, Ferastral, for the treatment of iron deficiency anaemia has been performed. The study was designed to determine the dose schedule, efficacy and tolerance of the drug. Two dose intervals were used, 500 mg of iron once a week or every third day. The study comprised 26 adult patients. After single doses of 500 mg of Ferastral given every third day levels of iron and unsaturated iron binding capacity (UIBC) in serum were estimated. Maximum values of iron in serum after the first injection were reached after 24 hours in two patients. After the second injection there was a further increase in the iron concentration with maximum values after 24 to 48 hours. A decrease in UIBC was seen in all patients. Urinary excretion of iron was about 15%. Most of the excretion took place during the first 72 hours following the injection. The haemoglobin increase was more rapid in the group receiving 500 mg of iron every third day. The difference was statistically significant two to four weeks after commencing treatment. After five weeks the difference in haemoglobin increase was no longer statistically significant. After eight weeks the mean haemoglobin had reached 13.1 g/100 ml in the group treated once a week and 13.4 g/100 ml in the group treated every third day. The preparation was well tolerated by all patients treated. No local or general side effects were observed.
Ferastral, a new iron-poly (sorbitol-gluconic acid) complex for parenteral use has been given to 22 patients with iron deficiency anaemia. The patients were divided in two groups. Group I received a suboptimal dose of Ferastral iron corresponding to 90% of the iron calculated to normalize the haemoglobin value. Increases in total haemoglobin and also blood losses were measured. The availability of the injected iron for haemoglobin synthesis ranged from 63% to 111%. Group II received an amount of Ferastral-iron calculated to be necessary for normalization of the haemoglobin plus an additional 500 mg of Ferastral-iron. In this group the haemoglobin increase was rapid. In 7 weeks 10 out of 14 patients had reached a normal haemoglobin level.
An investigation has been carried out to study the efficacy of iron-poly (sorbitol-gluconic acid) complex (Ferastral) in the treatment of iron deficiency anaemia. Ferastral was given by the intramuscular route every second or third day in a dose of 500 mg, divided in two injections. These were compared with the results of a group treated with iron-dextran given by Total Dose Infusion (TDI). A total of 38 patients were treated with either Ferastral or iron-dextran by TDI, respectively, given according to random allocation. The total dose of iron given in both groups was 1 500 mg of elemental iron. The parameters investigated were haematocrit and haemoglobin. Side-effects were also recorded. The results in the group treated with Ferastral where the mean initial haemoglobin value was 9.5 g/100 ml showed a mean haemoglobin increase to 13.2 g/100 ml after eight weeks. Initial haemoglobin values and haemoglobin increase for iron-dextran by TDI were quite similar. Three patients in the Ferastral group had transient discolouration at the site of injection and one patient in the iron-dextran TDI-group had a serious allergic reaction.
A specific method is described for selecting thermosensitive mutants of Escherichia coli K-12 able to grow on 2-keto-3-deoxy-D-gluconate (KDG) and D-glucuronate at 2, but not at 42 degrees C. The extensive analysis of one such mutant is consistent with the conclusion that the carrier molecule responsible for KDG and glucuronate uptake becomes thermolabile. (i) Growth on a variety of carbon sources is perfectly normal at 28 and 42 degrees C, whereas in the same temperature range it gradually diminishes on KDG and glucuronate. (ii) The apparent Km value for KDG is about twofold in the range 25 to 40 degrees C. In the same temperature range, the Vmax values for KDG influx are higher for the mutant compared with those of the wild-type strain, but the optimum temperature is 34 degrees C instead of 38 degrees C. On the contrary, the Vmax values for glucuronate influx are lower for the mutant than for the parental strain, and the optimum temperature for both strains is shifted beyond 40 degrees C. (iii) The activation energies for KDG and glucuronate uptake are about twofold higher in the mutant than in the wild-type strain. (iv) Kinetics of counterflow under deenergized conditions (overshoot) at different temperatures indicate that the defect is located in the translocation step rather than in the processes involved in energy coupling. (v) The first-order rate constants for thermal denaturation are, respectively, 2.5- and 5-fold higher at 40 and 30 degrees C in the mutant than in the wild-type strain, and the activation energy for thermal denaturation is lower. (vi) The carrier molecule in the mutant is also much more sensitive to denaturation by N-ethylmaleimide. (vii) Four independent thermosensitive mutations and one revertatn were located by transduction in or near the kdgT locus, defined previously as the site of nonconditional KDG transport-negative mutations. These results support the conclusion that kdgT represents the structural gene coding for the KDG transport system.
A single oral dose of 4-46 mmol calcium gluconate at pH 5-6 was administered intragastrically to 15 male volunteers without gastrointestinal disease. There was a significant rise in acid output from 30-90 minutes after the calcium was given compared with the basal hourly collection. The serum gastrin level 30 minutes after calcium administration was significantly raised, but no correlation could be demonstrated between the acid and gastrin responses. Serum calcium levels were unchanged throughout. An equimolar dose of magnesium sulphate had no such effects. This study suggests that the intragastric administration of calcium results in independent release of gastric acid and gastrin from the gastric mucosa.
A new isotope, 99Tcm-gluconate, for detection of myocardial infarction has been investigated experimentally. Great differences in isotope uptake between infarcted myocardium and normal myocardium were found in dogs. A close correlation was found between the isotope uptake and the uptake of basic fuchsin (HBFP) at microscopy in early myocardial infarcts.
A new isotope compound, 99Tcm-gluconate, for detection of myocardial infarction has been tested in dogs. A close correlation was found between the isotope uptake measured in vivo with a gamma camera and the infarct weight of early irreversible myocardial infarcts.