Vitamin K-deficient Diet Research Articles

Vitamin K Status Influences Brain Sulfatide Metabolism in Young Mice and Rats

The established role of vitamin K in nutrition is as a cofactor in the post-translational conversion of specific glutamyl to γ-carboxyglutamyl (Gla) residues in a limited number of proteins. Administration of the vitamin K antagonist warfarin has previously been shown to decrease brain sulfatide concentrations and decrease brain galactocerebroside sulfotransferase (GST) activity in young mice. A dietary deficiency of vitamin K has now been shown to decrease (P < 0.01) brain sulfatide concentrations of 30-d-old mice significantly (by 21%). Male 21-d-old rats fed an excess of vitamin K for 7 or 14 d had 26 and 31% (P < 0.05) greater GST activity and 15 and 18% (P < 0.05) greater brain sulfatide concentrations, respectively, than controls fed a vitamin K-deficient diet. Male 21-d-old rats fed a diet containing 500 mg of phylloquinone/kg diet had an intermediate response and were vitamin K sufficient by normal criteria. The vitamin K response was observed when either phylloquinone or menaquinone-4 was fed as a source of the vitamin. These data suggest that in addition to its recognized role in Gla synthesis, vitamin K status is important in the maintenance of normal complex lipid sulfatide metabolism in young rats and mice.

Finding the optimal dose of vitamin K1 to treat vitamin K deficiency and to avoid anaphylactoid reactions.

Vitamin K1 injection induces severe dose-related anaphylactoid reactions and overdose for the treatment of vitamin K deficiency. We aimed to find an optimal and small dose of vitamin K1 injection to treat vitamin K deficiency and avoid anaphylactoid reactions in animal. Rats were administered a vitamin K-deficient diet and gentamicin to establish vitamin K deficiency model. Behaviour tests were performed in beagle dogs to observe anaphylactoid reactions. The results showed an increased protein induced by vitamin K absence or antagonist II (PIVKA-II) levels, a prolonging of prothrombin time (PT) and activated partial thromboplastin time (APTT) and a decrease in vitamin K-dependent coagulation factor (F) II, VII, IX and X activities in the model group. In vitamin K1 0.01 mg/kg group, the liver vitamin K1 levels increased fivefold and the liver vitamin K2 levels increased to the normal amount. Coagulation markers PT, APTT, FVII and FIX activities returned to normal. Both in the 0.1 and 1.0 mg/kg vitamin K1 groups, coagulation functions completely returned to normal. Moreover, the amount of liver vitamin K1 was 40 (0.1 mg/kg) or 100 (1.0 mg/kg) times as in normal. Vitamin K2 was about 4 (0.1 mg/kg) or 5 (1.0 mg/kg) times as the normal amount. There was no obvious anaphylactoid symptom in dogs with the dose of 0.03 mg/kg, which is equivalent to the dose of 0.01 mg/kg in rats. These results demonstrated that a small dose of vitamin K1 is effective to improve vitamin K deficiency and to prevent anaphylactoid reactions, simultaneously.

Synthesis of 2-methyl-1,4-naphthoquinones with higher gamma-glutamyl carboxylase activity than MK-4 both in vitro and in vivo

Vitamin K is the collective term for compounds that share a 2-methyl-1,4-naphthoquinone ring, but differ in the side-chain at the 3-position. We synthesized novel 2-methyl-1,4-naphthoquinone derivatives with different side chain length at the 3-position. Derivatives with C-14 and C-16 tails showed the highest in vitro bioactivity resulting in 2.5 and 2-fold higher carboxylated osteocalcin synthesis in MG63 cells than menaquinone-4 (MK-4, form of vitamin K2). Longer side chain lengths resulted in lower bioactivity. The in vivo vitamin K activity of the C-14 tail derivative was further tested in WKY rats receiving a vitamin K-deficient diet that resulted in a 40% decrease of prothrombin activity. The C-14 tail derivative was able to counteract the effects on vitamin K deficiency induced by the diet and resulted in the complete restoration of prothrombin activity. Compared to naturally occurring forms of vitamin K, synthetic vitamin K derivatives may have higher bioactivity and different pharmacological characteristics that are more favorable for use as supplements or in clinical settings.

Establishing a rat model for the study of vitamin K deficiency.

The main vitamin K-deficient model, minidose warfarin, is different from the pathological mechanism of vitamin K deficiency, which is a shortage of vitamin K. The objective of this study was to establish a new method of vitamin K-deficient model combining a vitamin K-deficient diet with the intragastrical administration of gentamicin in rats. The clotting was assayed by an automated coagulation analyser. The plasma PIVKA-II was assayed by ELISA. The vitamin K status was detected by an HPLC-fluorescence system. In thediet- and gentamicin-induced vitaminK-deficient 14-day group, the rats had undetected vitamin K1 and vitamin K2 in the liver and a prolonged APTT. In the 21-day group, there was also a prolonged PT and a decrease of the FIX activities. In the 28-day group, the undetected vitamin K1 and vitamin K2, the prolonged PT and APTT, and the decrease of the FII, FVII, FIX, and FX activities prompted the suggestion that there were serious deficiencies of vitamin K and vitamin K-dependent coagulation in rats. It is suggested that thediet- and gentamicin-induced vitamin K-deficient 14-day or 21-day model can be used for studies related to the status of vitamin K. The vitamin K-deficient 28-day model can be appliedto research involving both the status of vitamin K and of vitamin K-dependent coagulation. In conclusion, the combination of a vitamin K-deficient diet with the administration of gentamicin results in a useful model of vitamin K-deficieny.

The Effect of Parental Vitamin K Deficiency on Bone Structure in Mummichog Fundulus heteroclitus

AbstractThe effect of parental vitamin K deficiency on developing bone structure was examined in mummichog (Fundulus heteeroclitus) larvae. Larvae from fish fed a vitamin K‐deficient diet had abnormal vertebral formation, whereas larvae from fish fed a vitamin K‐rich diet showed a significantly lower incidence of abnormality 5 d post‐hatch. Larvae from fish that had been fed either the vitamin K‐rich or the vitamin K‐deficient diet had a high rate of abnormality when reared on a vitamin K‐deficient diet for 30 d. Larvae from fish fed a vitamin K‐rich diet that were reared on a vitamin K‐rich diet showed a low rate of abnormality. Vertebral bone structure of larvae fed a vitamin K‐deficient diet for 30 d was thin and rough, and seemed to have repaired fine fractures of the bone surface. In contrast, this type of structural abnormality was not observed in any larvae fed a vitamin K (phylloquinone) rich diet. These results imply that vitamin K deficiency causes the formation of thin and weak bone, and induces bone structure abnormality both in early development and during growth.

Monitoring Hypocoagulant Conditions in Rat Plasma: Factors Determining the Endogenous Thrombin Potential of Tissue Factor-Activated Plasma

Automated human plasma, continuous monitoring of the formation and inactivation of thrombin during the coagulation process provides an adequate way to detect hypo- and hypercoagulant conditions. Here, we describe an analogous procedure to determine the endogenous thrombin potential (ETP), i. e. the free thrombin concentration-time integral, of coagulating rat plasma. When activated with tissue factor, the ETP of plasma from Wistar rats was comparable to the ETP of human plasma, in spite of a relatively short half-life time of free thrombin in rat plasma. The ETP was highly sensitive to heparin as well as to administration of vitamin K antagonist or feeding of the animals with a vitamin K-deficient diet. In plasma that was activated under sub-optimal conditions (reduced levels of tissue factor or vitamin K-dependent coagulation factors), the ETP increased with the rate of thrombin formation in the first minutes of the coagulation process. Since both parameters are dependent of the prothrombin concentration, it appears that this level plays an important role in determining both the initial and total activity of the coagulation system. Thus, automated measurement of free thrombin during the coagulation process of rat plasma allows a detailed analysis of hypocoagulability in this animal model.

Conversion of Dietary Phylloquinone to Tissue Menaquinone-4 in Rats is Not Dependent on Gut Bacteria1-5

The ability of male rats to accumulate menaquinone-4 (MK-4) in tissues when fed a vitamin K-deficient diet supplemented with intraperitoneal phylloquinone (K) as the sole source of vitamin K for 14 d was assessed. In both conventionally housed controls and gnotobiotic rats, supplementation with the equivalent of 1500 μg vitamin K/kg diet increased (P < 0.001) tissue MK-4 concentrations above those of controls fed a vitamin K-deficient diet. MK-4 concentrations were ∼5 ng/g (11 pmol/g) in liver, 14 ng/g in heart, 17 ng/g in kidney, 50 ng/g in brain and 250 ng/g in mandibular salivary glands of gnotobiotic rats. MK-4 concentrations in conventionally housed rats were higher than in gnotobiotic rats in heart (P < 0.01), brain (P < 0.01) and kidney (P < 0.05) but lower in salivary gland (P < 0.05). Cultures of a kidney-derived cell line (293) converted K to the epoxide of MK-4 in a manner that was dependent on both time of incubation and concentration of vitamin K in the media. A liver-derived cell line (H-35) was less active in carrying out this conversion. These data offer conclusive proof that the tissue-specific formation of MK-4 from K is a metabolic transformation that does not require bacterial transformation to menadione as an intermediate in the process.

Comparison of intestinal absorption of vitamin K 2 (menaquinone) homologues and their effects on blood coagulation in rats with hypoprothrombinaemia

To examine the physiological activities of vitamin K 2 (menaquinone, MK) homologues with different numbers of isoprene units, MK with 1–14 isoprene units and menadione (MK-0) were administered to rats with hypoprothrombinaemia, and the absorption, concentration in liver and ameliorating effect of these MK on hypoprothrombinaemia were compared. Hypoprothrombinaemia was induced by giving a vitamin K-deficient diet and warfarin (0.06 mg/kg body weight) for 8 days. Before MK treatment, the MK were undetectable in plasma and liver. At 6 hr after oral MK administration (0.1 mg/kg): MK was not detected in the plasma in rats treated with MK with 1, 2, 3 or more than 12 isoprene units; the MK level in the liver was increased but blood coagulation activity was not improved in rats treated with MK with 0, 9, 10 or 11 isoprene units; the MK level in the liver was increased and hypoprothrombinaemia was slightly improved in rats treated with MK with 7 or 8 isoprene units; and the MK level in the liver was increased and hypoprothrombinaemia was markedly improved in rats treated with MK with 4, 5 or 6 isoprene units. Almost identical results were observed 3 hr after intravenous injection of MK with 4, 5 or 6 isoprene units (10 nmol/kg). These findings suggest that the number of isoprene units of MK is an important factor in its absorption and incorporation into the liver and that the ameliorating effect of MK on hypoprothrombinaemia does not parallel their concentrations in the liver.

Vitamin K Deficiency Does Not Functionally Impair Skeletal Metabolism of Laying Hens and Their Progeny

AbstractThe purpose of this research was to determine the effect of vitamin K deficiency on indices of skeletal metabolism in laying hens, developing embryos and young growing chickens. Laying hens were fed a vitamin K-deficient diet for 28 wk, which resulted in impaired blood clotting and reduced bone γ-carboxyglutamic acid (Gla) concentration compared with vitamin K-sufficient hens. However, this treatment did not influence egg production, eggshell deposition or other reproductive performance criteria. Vitamin K-deficient embryos were able to mobilize sufficient quantities of calcium for normal skeletal development, although they exhibited severe reduction in blood clotting and bone Gla concentration. Similar results were obtained from progeny of both vitamin K-sufficient and -deficient hens fed deficient diets for 4 wk after hatching. These results indicate that a severe reduction in skeletal protein Gla concentration does not interfere with normal development of this tissue.

Effects of menatetrenone on the decrease in calcium balance induced by vitamin K-deficient diet and sodium loading in rats.

The effects of menatetrenone (2-methyl-3-tetraprenyl-1,4-naphthoquinone, MK-4) on calcium balance were studied in male Sprague-Dawley rats. Experiment 1: Rats in metabolic cages that were fed a vitamin K-deficient diet and injected daily with latamoxef (100 mg/kg, i.p.) were either treated or untreated with MK-4 for 7 days. Daily food intake, urine volume and feces weight were determined, and calcium concentration in these samples was measured. Calcium balance was calculated as the difference between calcium intake and urinary and fecal calcium excretion. Cumulative calcium balance in the vitamin K-deficient group treated with latamoxef was lower than that in normal rats; this balance was significantly improved by MK-4 (1 and 10 mg/kg, s.c.) administered for 7 days. Experiment 2: Rats were fed a vitamin K-deficient diet containing 4.6% sodium chloride for 6 weeks. MK-4 was administered as a dietary supplement. Forty-eight-hour calcium balance, determined once a week, was significantly reduced compared with that of normal rats after 3 and 5 weeks; the balance was restored dose-dependently by MK-4 administration (1 and 10 mg/kg). Experiment 3: Rats were subjected to the same experimental conditions as experiment 2 for 6 weeks, and intestinal calcium transport was determined using an everted gut-sac technique. Calcium transport was reduced by the high sodium, vitamin K-deficient diet, and this reduction was restored by MK-4 administration (10 mg/kg). These results suggest that MK-4 improves the reduced calcium balance by increasing intestinal calcium absorption in these rats.

Effects of Menatetrenone on the Decrease in Calcium Balance Induced by Vitamin K-Deficient Diet and Sodium Loading in Rats

Effects of Menatetrenone on the Decrease in Calcium Balance Induced by Vitamin K-Deficient Diet and Sodium Loading in Rats

Depression of liver microsomal vitamin K epoxide reductase activity associated with antibiotic-induced coagulopathy

Hypoprothrombinemic changes in blood coagulation parameters, such as prolongation of prothrombin time, increase in the level of plasma protein induced by vitamin K absence, and decrease in plasma prothrombin level, were detected in rats fed a vitamin K-deficient diet. These changes were enhanced by the administration of β-lactam antibiotics containing N-methyltetrazolethiol, thiadiazolethiol or methyl-thiadiazolethiol. Microsomal vitamin K epoxide reductase activity was suppressed with the maximum effect at 1–2 days after the treatment and with recovery, thereafter, gradually to the normal level after 5–7 days. Hypoprothrombinemic alterations in blood coagulation parameters following a single administration of antibiotic to vitamin K-deficient rats were somewhat delayed compared with the change in the epoxide reductase activity, but the effects of the antibiotic on both blood coagulation parameters and the enzyme activity disappeared completely 7 days after the antibiotic treatment. Antibiotic-induced depression of the epoxide reductase activity was observed even in the vitamin K sufficient rats, although the hypoprothrombinemic changes in the blood coagulation parameters did not develop. Vitamin K administration could normalize the blood coagulation parameters in the hypoprothrombinemic rats caused by treatment with the antibiotics but without recovery of the decreased epoxide reductase activity. These results suggest that some antibiotics inhibit liver microsomal vitamin K epoxide reductase, which causes hypoprothrombinemia to develop under vitamin K-deficient conditions.

Studies on Oxacephem Antibiotics: Comparison of the Effects of 1-Oxa and 1-Thia Cephalosporins on Blood Coagulation Activities and Vitamin K Metabolism in Rats

Oxacephem antibiotics have been developed to increase the antibacterial activity of cephem antibiotics, but the effect of 1 -oxygen replacement of cephem antibiotics on blood coagulation activities is not yet known. Therefore, latamoxef (LMOX), flomoxef (FMOX) and their 1 -S congeners were examined for their effects on prothrombin time, activated partial thromboplastin time, plasma prothrombin and Factor VII levels, plasma and liver descarboxyprothrombin (PIVKA-II) levels, and liver microsomal vitamin K epoxide reductase activities in rats kept on a vitamin K-deficient diet. Under the vitamin-deficient states, LMOX, FMOX and their 1-S congeners inhibited the vitamin K epoxide reductase, although the effect of FMOX or its congener was much less than that of LMOX, and they decreased the blood clotting activities in rats fed a vitamin K-deficient diet. However, no difference was found in these effects between LMOX and its 1 -S congener or between FMOX and its 1-S congener. This result suggests that the 1-oxygen replacement of cephem antibiotics is not responsible for the hypoprothrombinemic effect of the antibiotics.

Studies on oxacephem antibiotics: Comparison of the effects of 1-oxa and 1-thia cephalosporins on blood coagulation activities and vitamin K metabolism in rats.

Oxacephem antibiotics have been developed to increase the antibacterial activity of cephem antibiotics, but the effect of 1-oxygen replacement of cephem antibiotics on blood coagulation activities is not yet known. Therefore, latamoxef (LMOX), flomoxef (FMOX) and their 1-S congeners were examined for their effects on prothrombin time, activated partial thromboplastin time, plasma prothrombin and Factor VII levels, plasma and liver descarboxyprothrombin (PIVKA-II) levels, and liver microsomal vitamin K epoxide reductase activities in rats kept on a vitamin K-deficient diet. Under the vitamin-deficient states, LMOX, FMOX and their 1-S congeners inhibited the vitamin K epoxide reductase, although the effect of FMOX or its congener was much less than that of LMOX, and they decreased the blood clotting activities in rats fed a vitamin K-deficient diet. However, no difference was found in these effects between LMOX and its 1-S congener or between FMOX and its 1-S congener. This result suggests that the 1-oxygen replacement of cephem antibiotics is not responsible for the hypoprothrombinemic effect of the antibiotics.

Fracture Healing and Osteocalcin Metabolism in Vitamin K Deficiency

Osteocalcin (a vitamin K-dependent, bone-specific protein) is widely accepted as a marker of osteoblastic activity. The present study was conducted to determine if a vitamin K deficiency would affect fracture healing by virtue of an alteration in osteocalcin metabolism. Thirty male Sprague-Dawley rats were divided into two groups. The control group was fed a diet that was lacking in, but offered water replete with vitamin K. The experimental group was fed a vitamin K-deficient diet and was offered water that was lacking in vitamin K. After two weeks, vitamin K deficiency was established in the experimental group as shown by decreased urinary excretion of gamma-carboxyglutamic acid and an elevation of serum prothrombin times to between two to two and one-half times the control values. At this time, a standard, closed femoral fracture was produced. Six weeks later, the animals were killed. The bones were biomechanically tested in torsion. Subsequent to mechanical testing, the calluses were retrieved, and the osteocalcin content and the degree of gamma carboxylation of the osteocalcin in the calluses were measured. The results show that despite significant alterations in the gamma carboxylation of osteocalcin and elevation of prothrombin times to two to two and one-half times the control values, there were no differences in the mechanical properties of the calluses. Furthermore, there were no differences in the content or gamma carboxylation of osteocalcin in these calluses. Apparently, in vitamin K deficiency, fracture callus achieves normal mechanical properties and may have a mechanism for the gamma carboxylation of glutamic acids in osteocalcin despite a substantial depression of this activity in the rest of the body.

In vivo effects of β-lactam antibiotics and heterocyclic thiol compounds on vitamin K-dependent carboxylation activity and blood coagulation factors in vitamin K-deficient rats

The vivo effects of heterocyclic thiol compounds, corresponding to the 3′-position substituents of several β-lactam antibiotics, on blood coagulation factors and on liver microsomal γ-glutamylcarboxylation (γ-carboxylation) activity were evaluated in rats maintained on a vitamin K-deficient diet. These rats, when compared to normal control animals, exhibited hypoprothrombinemic changes: prolongation of both prothrombin time and activated partial thromboplastin time, decreases in factor VII and plasma prothrombin, and increases in PIVKA II (descarboxyprothrombin) both in plasma and liver. They also displayed a marked increase in liver microsomal γ-carboxylation activity. These blood coagulation variables could be altered markedly by administering various heterocyclic thiol compounds to the vitamin K-deficient rats, although these compounds did not inhibit γ-carboxylation activity in an assay system using phylloquinone. A similar pattern of alteration was observed when some β-lactam antibiotics were administered. Increased microsomal γ-carboxylation activity in antibiotic-treated vitamin K-deficient rats was normalized by the administration of vitamin K, concomitant with the recovery of blood coagulation variables to the normal range. The results indicate that antibiotic-induced hypoprothrombinemia in vivo is not caused by inhibition of enzymes of the γ-carboxylation system, such as vitamin K reductase and γ-glutamylcarboxylase, but is related to the endogenous vitamin K level.

Vitamin K-Reversible Hypoprothrombinemia in Rats I. Sex Differences in the Development of Hypoprothrombinemia and the Effects of Beta-Lactam Antibiotics

Male and female rats were fed an ordinary diet which contained about 500 ng vitamin K/g or a vitamin K-deficient diet containing less than 5 ng vitamin K/g. Hypoprothrombinemic changes such as prolongation of the prothrombin time (PT) and activated partial thromboplastin time (APTT) were detected in male rats within 4–6 days after feeding of the vitamin K deficient diet. Blood clotting factor VII and descarboxy prothrombin (PIVKA) levels changed rapidly, with maximum alteration at 2–4 days. Similar changes in factor VII and PIVKA levels were observed in female rats, but they appeared only after feeding of the K deficient diet for a long period. PT and APTT in female rats showed slight or no alteration even after 10 day feeding of the K-deficient diet. These results indicate that male rats are more susceptible to vitamin K deficiency than female rats. Administration of latamoxef led to a dose-dependent development of hypoprothrombinemia in vitamin K-deficient female rats. The hypoprothrombinemia in vitamin K-deficient female rats was caused by beta-lactam antibiotics with N-methyltetrazolethiol, thiadiazolethiol and methyl-thiadiazolethiol as the 3’-position substituent of the cephem nucleus.

Vitamin K-reversible hypoprothrombinemia in rats. I. Sex differences in the development of hypoprothrombinemia and the effects of beta-lactam antibiotics.

Male and female rats were fed an ordinary diet which contained about 500 ng vitamin K/g or a vitamin K-deficient diet containing less than 5 ng vitamin K/g. Hypoprothrombinemic changes such as prolongation of the prothrombin time (PT) and activated partial thromboplastin time (APTT) were detected in male rats within 4-6 days after feeding of the vitamin K deficient diet. Blood clotting factor VII and descarboxy prothrombin (PIVKA) levels changed rapidly, with maximum alteration at 2-4 days. Similar changes in factor VII and PIVKA levels were observed in female rats, but they appeared only after feeding of the K deficient diet for a long period. PT and APTT in female rats showed slight or no alteration even after 10 day feeding of the K-deficient diet. These results indicate that male rats are more susceptible to vitamin K deficiency than female rats. Administration of latamoxef led to a dose-dependent development of hypoprothrombinemia in vitamin K-deficient female rats. The hypoprothrombinemia in vitamin K-deficient female rats was caused by beta-lactam antibiotics with N-methyltetrazolethiol, thiadiazolethiol and methyl-thiadiazolethiol as the 3'-position substituent of the cephem nucleus.

Vitamin K Reversible Hypoprothrombinemia in Rats II. Efficacy of Vitamin K on Latamoxef-Induced Coagulopathy in Rats

Feeding of a vitamin K-deficient diet caused the development of hypo-prothrombinemic changes in rats such as prolongation of prothrombin time (PT) and activated partial thromboplastin time (APTT), decreases in plasma prothrombin and clotting factor VII levels, and an increase in the descarboxyprothrombin (PIVKA) level in both plasma and liver. Successive administrations of latamoxef (LMOX) to the vitamin K-deficient rats resulted in the further enhancement of these changes. After the development of hypoprothrombinemia with LMOX, a single subcutaneous injection of vitamin K1 normalized most of these abnormalities in blood coagulation parameters within 6 hr. When vitamin Κ was given at 200 μg/kg, PT, APTT and the plasma PIVKA level showed normal values for at least 8 days even when the animals were fed a vitamin K-deficient diet and treated with LMOX during the recovery period. The amount of vitamin Κ required to maintain most of the blood coagulation parameters in the normal range was about 3 μg/kg/day. The plasma level of vitamin Κ was higher than 0.3-0.5 ng/ml when the blood coagulation parameters were maintained in the normal range.

Vitamin K reversible hypoprothrombinemia in rats. II. Efficacy of vitamin K on latamoxef-induced coagulopathy in rats.

Feeding of a vitamin K-deficient diet caused the development of hypoprothrombinemic changes in rats such as prolongation of prothrombin time (PT) and activated partial thromboplastin time (APTT), decreases in plasma prothrombin and clotting factor VII levels, and an increase in the descarboxyprothrombin (PIVKA) level in both plasma and liver. Successive administrations of latamoxef (LMOX) to the vitamin K-deficient rats resulted in the further enhancement of these changes. After the development of hypoprothrombinemia with LMOX, a single subcutaneous injection of vitamin K1 normalized most of these abnormalities in blood coagulation parameters within 6 hr. When vitamin K was given at 200 micrograms/kg, PT, APTT and the plasma PIVKA level showed normal values for at least 8 days even when the animals were fed a vitamin K-deficient diet and treated with LMOX during the recovery period. The amount of vitamin K required to maintain most of the blood coagulation parameters in the normal range was about 3 micrograms/kg/day. The plasma level of vitamin K was higher than 0.3-0.5 ng/ml when the blood coagulation parameters were maintained in the normal range.