Detection of vitamin K deficiency by use of an enzyme-linked immunosorbent assay for circulating abnormal prothrombin

Relationship between vitamin K dependent coagulation factors and anticoagulants (protein C and protein S) in neonatal vitamin K deficiency

To determine the relationship between vitamin K dependent coagulation factors and natural anticoagulants, namely protein C and protein S, in various degrees of vitamin K deficiency, plasma values for clotting activity, protein induced by vitamin K absence (PIVKA-II), protein C antigen, gamma-carboxy protein C antigen, and protein S antigen including total and free fractions and activity of protein C were measured in 66 full term and healthy breast fed neonates who did not receive vitamin K supplement at birth. The 66 neonates were divided into a control group (17 cases) and a low group (49 cases) according to their values for clotting activity--that is, > or = 20% or < 20% during the first six days of life--and vitamin K was immediately given when the neonates showed values < 20%. In the low group clotting activity gamma-carboxy protein C, free protein S, and protein C activity was significantly decreased to a minimum on day 2 or 3, and increased in parallel after vitamin K administration. Furthermore, they were positively correlated with one another and inversely cor-correlated with the PIVKA-II concentrations. These findings suggest that simultaneous gamma-carboxylation of coagulation factors and proteins C and S acts to maintain both coagulation and anticoagulation activities in parallel at various concentrations of vitamin K. The breast milk intake in the group with low values of clotting activity was significantly lower than that in the control group during the first three days of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Vitamin K and maintenance of skeletal integrity in adults

PURPOSE

To determine the role of vitamin K status in the maintenance of skeletal integrity in adults.

PATIENTS AND METHODS

1. Bone mineral density (BMD) was measured by quantitative digital radiography (QDR) in 50 patients taking a vitamin K antagonist (warfarin) who were recruited from a large urban cardiology practice, and 50 age-, sex- and race-matched controls recruited from the community. 2. The relationship of BMD versus indices of vitamin K status (determined by measuring levels of vitamin K and descarboxyprothrombin in the plasma) in 113 nonanticoagulated adults was assessed.

RESULTS

Measurements of BMD in the hip and spine were similar in anticoagulated subjects and matched controls. Multivariate analysis revealed that use of warfarin was not associated with a lower BMD. Ninety-five percent confidence intervals excluded a 0.06 g/cm2 reduction in BMD associated with the use of warfarin. Indices of vitamin K status did not correlate with BMD in normal subjects.

CONCLUSIONS

Patients receiving long-term maintenance therapy with a vitamin K antagonist have normal bone density. BMD is unrelated to vitamin K status in nonanticoagulated subjects. These data suggest that vitamin K does not have a major role in maintenance of skeletal integrity in adults.

The effect of IL-6 on the des-gamma-carboxy prothrombin synthesis in human hepatoma cells

Effects of several cytokines on des-gamma-carboxy prothrombin (PIVKA II) synthesis in human hepatoma cells were investigated to know the process of PIVKA II production during a liver allograft rejection. Human recombinant interleukin-6 (IL-6) significantly stimulated the PIVKA II synthesis without any influence on the cell proliferation. The effect was almost completely neutralized by the specific anti-IL-6 antibody. Neither tumor necrosis factor (TNF), interleukin-1 (IL-1) nor interferon-gamma (IFN-gamma) had such a stimulative effect. IL-6 appears to stimulate PIVKA II production, and would be a candidate of factors that enhance the production of PIVKA II during a liver allograft rejection.

Effects of oral and intramuscular vitamin K prophylaxis on vitamin K1, PIVKA-II, and clotting factors in breast fed infants

A randomised clinical trial was conducted to establish the effects of oral and intramuscular administration of vitamin K at birth on plasma concentrations of vitamin K1, proteins induced by vitamin K absence (PIVKA-II), and clotting factors. Two groups of about 165 healthy breast fed infants who received at random 1 mg vitamin K1 orally or intramuscularly after birth were studied at 2 weeks and 1 and 3 months of age. Although vitamin K1 concentrations were statistically significantly higher in the intramuscular group, blood coagulability, activities of factors VII and X and PIVKA-II concentrations did not reveal any difference between the two groups. At 2 weeks of age vitamin K1 concentrations were raised compared with reported unsupplemented concentrations and no PIVKA-II was detectable. At 3 months vitamin K1 concentrations were back at unsupplemented values and PIVKA-II was detectable in 11.5% of infants. Therefore, a repeated oral prophylaxis will be necessary to completely prevent (biochemical) vitamin K deficiency beyond the age of 1 month.

Vitamin K status in cystic fibrosis

Appearance of PIVKA-II (protein induced by vitamin K absence-II) in serum is a biochemical sign of insufficient vitamin K-dependent carboxylation of prothrombin. Plasma concentrations of PIVKA-II and vitamin K1 were determined in 24 children with cystic fibrosis. Eight were supplemented with vitamin K1. The purpose of the study was to determine the occurrence of vitamin K deficiency in cystic fibrosis and to evaluate the effect of vitamin K supplementation. PIVKA-II was detectable in only one unsupplemented child. In this patient, the concentration of vitamin K1 was below the limit of detection of 60 ng/l. Vitamin K1 levels in the other unsupplemented children were normal (mean 476 ng/l = 1 mmol/l). The supplemented patients showed extremely high levels of vitamin K1 (mean 22445 ng/l = 50 nmol/l). In conclusion, vitamin K deficiency occurs infrequently in cystic fibrosis. Checking the coagulation system is advised, but routine vitamin K supplementation is not recommended. If additional vitamin K is needed, the starting dose should not exceed 1 mg daily.

Plasma abnormal prothrombin (PIVKA-II): a new and reliable marker for the detection of hepatocellular carcinoma

We evaluated the clinical usefulness of a protein induced by vitamin K absence, antagonist-prothrombin (PIVKA-II), in detecting hepatocellular carcinoma (HCC) specifically in patients with liver cirrhosis, and the possible correlation between levels of PIVKA-II and pathological features of HCC. Plasma levels of PIVKA-II and alpha-fetoprotein (AFP) were measured in 628 patients with various diseases, including 253 with liver cirrhosis and 116 with HCC. PIVKA-II was detected (greater than or equal to 0.1 arbitrary unit/mL) in 54.3% of HCC and the concentration showed a positive correlation with the tumour size. As a screening test for the detection of HCC, PIVKA-II produced values comparable with those of AFP with a sensitivity, specificity and validity of 52.8, 98.8 and 51.6% respectively. Sixteen of 45 patients (37%) with HCC who had low AFP (less than 100 ng/mL) levels were positive for PIVKA-II. No apparent relationship, however, could be found between the levels of PIVKA-II and the aetiology or pathological findings of HCC. These results suggest that PIVKA-II can be a reliable marker for detecting HCC in patients with liver cirrhosis.

Relationship between pathologic prognostic factors and abnormal levels of des-γ-carboxy prothrombin and α-fetoprotein in hepatocellular carcinoma

The relationship between pathologic prognostic factors and abnormal levels of des-gamma-carboxy prothrombin and alpha-fetoprotein was investigated in 42 patients with resectable hepatocellular carcinoma. The frequencies of macroscopic massive type, intrahepatic metastasis, and portal vein tumor thrombus were significantly higher in patients with positive des-gamma-carboxy prothrombin (p less than 0.05) but not with alpha-fetoprotein. Other histologic factors in tumorous and nontumorous tissues were not significantly different irrespective of the positivity of these markers. In patients with tumors not more than 6 cm in diameter, the frequency of intrahepatic metastasis was positively correlated with the positivity of des-gamma-carboxy prothrombin (p less than 0.05) and inversely with that of alpha-fetoprotein (p less than 0.05). Furthermore, intrahepatic metastasis was most frequently observed in patients with positive des-gamma-carboxy prothrombin and negative alpha-fetoprotein (eight of nine) and least frequently in cases with negative des-gamma-carboxy prothrombin and positive alpha-fetoprotein (one of eight). These findings indicated that both des-gamma-carboxy prothrombin and alpha-fetoprotein might be useful markers for the prediction of intrahepatic spread of hepatocellular carcinoma.

Changes of plasma des-gamma-carboxy prothrombin levels in patients with hepatocellular carcinoma in response to vitamin K

The effect of menaquinone-4 (MK-4, vitamin K2) was studied on des-gamma-carboxy prothrombin (DCP or PIVKA-II) levels in three subjects with vitamin K deficiency and five patients with hepatocellular carcinoma (HCC) with positive DCP. The half-life of DCP in HCC patients after intravenous MK-4 administration (50 mg daily for 14 days) was determined to be 60 hours, identical to that found in vitamin K-deficient subjects who received MK-4. When a single dose of MK-4 (10 mg) was given intravenously to three patients with HCC and elevated DCP, the levels decreased with a reduction rate identical to that in vitamin K-deficient subjects for the first 1 to 3 days, followed by an increase reaching the previous level in 7 to 10 days. Changes in plasma coagulant activity were compared between subjects with vitamin K deficiency and those with HCC before and after a single dose of MK-4 (10 mg). The activity increased in DCP-positive patients with HCC as in vitamin K-deficient subjects who received the same single dose of MK-4. The increase was greater in HCC patients with higher DCP levels. These results suggest that the level of plasma DCP in patients with HCC responded to vitamin K with the same sensitivity as that in vitamin K-deficient subjects. When patients with HCC underwent effective tumor therapy (resection or arterial embolization), the reduction rate (slope of DCP decline) was found to be identical to that in vitamin K-deficient subjects given with MK-4. In patients with less effective therapy, the reduction rate was smaller, or there was an increase in DCP. These observations strongly suggest that sequential measurements of the DCP reduction rate after treatment for HCC are useful for assessing therapeutic effects.

Clinical usefulness of des-gamma-carboxy prothrombin assay in early diagnosis of hepatocellular carcinoma

Des-gamma-carboxy prothrombin (DCP) was evaluated as a serological marker for hepatocellular carcinoma (HCC), particularly in patients with early HCC. In 1192 patients with various diseases, plasma DCP levels were measured by a newly developed enzyme immunoassay method using an anti-DCP monoclonal antibody. Of the 254 patients with HCC, 143 (56%) had abnormal DCP levels of greater than 0.1 AU/ml. In contrast, elevated DCP levels were rarely observed in patients with chronic hepatitis, liver cirrhosis, metastatic liver cancer, and other malignant tumors. Because no correlation was observed between DCP and alpha-fetoprotein (AFP), the combined measurement of these two complementary markers appears to be useful in the diagnosis of HCC. Since normal levels were observed in 29 of 30 patients (97%) with small liver tumors measuring 2 cm or less in diameter, the diagnostic application of the DCP assay to small liver tumors is limited. However, in patients with tumors larger than 2 cm, the plasma DCP assay may even be more useful than AFP. Among 46 patients with liver cirrhosis or chronic hepatitis who subsequently developed HCC, significantly increased DCP and AFP levels were observed in nine patients (20%) and 14 patients (30%), respectively, when a tumor was detected. When the results of both assays were combined, 19 patients (41%) had elevated levels of one or both markers. Although the plasma DCP assay alone is not sensitive enough to detect early small liver cancers, it could be applied as a complementary tumor marker together with AFP.(ABSTRACT TRUNCATED AT 250 WORDS)

Des-gamma-carboxyprothrombin detection by immunoblotting after polyacrylamide gel affinoelectrophoresis in human plasmas

In the absence of vitamin K or in the presence of the vitamin K antagonists, abnormal nonfunctional forms of prothrombin circulate in the blood. A reliable and reproducible technique, derived from traditional crossed affinoimmunoelectrophoresis in presence of calcium lactate, was developed and optimized. The technique is based on nondenaturing polyacrylamide gel affinoelectrophoresis, with calcium lactate, of plasma samples, followed by immunoblotting with rabbit anti-human prothrombin serum and detection with an anti-rabbit immunoglobulin peroxidase conjugate. Depending on the plasmas, one or two bands were visualized and quantified by densitometry of the immunoblots. The technique was able to detect abnormal des-gamma-carboxylated prothrombins at concentration of 0.1 microgram/mL.

Plasma des-gamma-carboxyprothrombin in the early stage of hepatocellular carcinoma

To evaluate the role of plasma des-gamma-carboxyprothrombin in the early diagnosis of hepatocellular carcinoma, we simultaneously studied both des-gamma-carboxyprothrombin activities by staphylocoagulase method and des-gamma-carboxyprothrombin antigen levels by enzyme immunoassay in 39 patients with early stage hepatocellular carcinoma (tumor size less than 3 cm in 21 patients, 3 to 5 cm in 18 patients); 68 patients had large hepatocellular carcinoma and 54 patients had chronic hepatitis or cirrhosis. Des-gamma-carboxyprothrombin levels by staphylocoagulase method (X) and enzyme immunoassay method (Y) on the same plasma specimens of hepatocellular carcinoma patients showed a linear correlation (Y = 0.15X - 10.5, r = 0.533, n = 67, p less than 0.001). Elevated des-gamma-carboxyprothrombin activities were present in 10 of 21 patients (47.6%) with hepatocellular carcinoma less than 3 cm, 66.7% of 18 with hepatocellular carcinoma 3 to 5 cm, 67.6% of 68 with hepatocellular carcinomas greater than 5 cm and 27.8% of 54 with chronic hepatitis or cirrhosis. The plasma des-gamma-carboxyprothrombin levels did not correlate with the tumor size or serum alpha-fetoprotein levels. Plasma des-gamma-carboxyprothrombin and serum alpha-fetoprotein measurements were comparable in the diagnosis of hepatocellular carcinoma because 22 (56.4%) and 21 (53.8%) of 39 patients with hepatocellular carcinoma less than 5 cm had increased des-gamma-carboxyprothrombin and alpha-fetoprotein levels, respectively. Up to 77% had an abnormal elevation in either marker.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of des-gamma-carboxy prothrombin as a marker protein of hepatocellular carcinoma

We measured des-gamma-carboxyglutamic acid prothrombin (protein induced by vitamin K absence or antagonist-Factor II: [PIVKA-II]) in plasmas of normal subjects, patients with thrombotic disease, those with hepatic disease including hepatocellular carcinoma, and those with carcinoma of other tissues, and compared the results with results of blood coagulation tests used for the examination of hepatic function. In addition, in the patients with hepatic disease, PIVKA-II and alpha-fetoprotein (AFP) levels were compared. The PIVKA-II level was frequently high in patients with thrombotic disease given warfarin therapy and those with hepatocellular carcinoma. However, in patients with thrombotic disease who were not given warfarin therapy, no significant correlation was seen between the PIVKA-II value and the results of the thrombotest or hepaplastin test, suggesting no association between the PIVKA-II level and the degree of impairment of hepatic function. In 70 patients with hepatocellular carcinoma, the percentage of patients positive for PIVKA-II (greater than or equal to 0.1 micrograms/ml) and those positive for AFP (greater than or equal to 20 ng/ml) were similar (77% and 74%, respectively). Pearson's correlation of coefficient between the PIVKA-II value and the AFP value in the 70 patients was 0.463. However, false-positive rates in patients with hepatic disease other than hepatocellular carcinoma were lower for PIVKA-II. Combined assessment of PIVKA-II and AFP increased positive rates and allowed exclusion of false-positive patients. The plasma PIVKA-II level is suggested to be useful as an indicator of warfarin control in patients with thrombotic disease, as a marker of hepatocellular carcinoma, and is particularly of value when assessed in combination with AFP.

Abnormal plasma prothrombin (PIVKA-II) levels in hepatocellular carcinoma

The concentration of abnormal prothrombin, or the protein induced by vitamin K absence or antagonist II (PIVKA-II) in 102 patients with hepatic disorders was measured by an enzyme immunoassay method. The concentration of PIVKA-II in the plasma was elevated in 11 out of 18 patients with hepatocellular carcinoma and also in a patient with hepatoblastoma. There was no correlation between serum alpha-fetoprotein and plasma PIVKA-II levels. The PIVKA-II level was normal in 11 patients who had metastatic carcinoma or cholangiocellular carcinoma. Moreover, benign diseases of the liver did not cause an elevation in PIVKA-II. PIVKA-II might be an useful marker of hepatocellular carcinoma because, like alpha-fetoprotein, its level changes in close relation to the effects of treatment.

Application of des-gamma-carboxy prothrombin as a complementary tumor marker with alpha-fetoprotein in the diagnosis of hepatocellular carcinoma

By means of staphylocoagulase, plasma des-gamma-carboxy prothrombin (DCP) was measured in 255 subjects. Of these, 59 were healthy controls, 100 had primary hepatocellular carcinoma (PHC), 33 had cirrhosis of the liver, 16 had hepatitis, 11 had metastatic carcinoma of the liver (MCL), and 36 subjects had previously been treated with anti-vitamin K drugs. The mean plasma DCP level in the healthy subjects was 3.02 VGH U/l. Of PHC patients 80% had DCP levels greater than 6 VGH U/l, which we regarded as probably abnormal. None of the patients with benign liver diseases (cirrhosis of liver or hepatitis) had DCP greater than 10 VGH U/l. Of the patients with MCL 54.54% had DCP greater than 6 VGH U/l. In our study DCP was found to be as sensitive a tumor marker as alpha-fetoprotein (AFP) in the diagnosis of PHC and was better in distinguishing PHC from benign liver disease. Of PHC patients 92% had at least one of the two tumor markers. Simultaneous determination of DCP and AFP should be applied in mass survey programs for detecting PHC, especially in countries with a high prevalence of hepatitis B virus infection.

Plasma concentrations of vitamin K1 and PIVKA-II in bottle-fed and breast-fed infants with and without vitamin K prophylaxis at birth

Plasma vitamin K1 and proteins induced by vitamin K absence (PIVKA) were assayed simultaneously 1-4 days and 29-35 days after delivery in three groups of infants: breast-fed not receiving vitamin K at birth (n = 12), bottle-fed without vitamin K administration at birth (n = 7) and breast-fed receiving 1 mg vitamin K1 administered by intramuscular injection at birth (n = 13). The bottle-fed infants had a significantly higher vitamin K1 plasma level than breast-fed infants who did not receive vitamin K1 at birth. Extremely high levels of vitamin K were obtained 1-4 days after intramuscular administration. At the age of 1 month, breast-fed infants had the same plasma vitamin K1 concentration whether or not they had received vitamin K1 supplements. Decarboxy prothrombin (PIVKA-II) a reliable indicator of biochemical vitamin K deficiency, was found in 5 out of 12 breast-fed and in 2 out of 6 bottle-fed infants who had not received supplemental vitamin K1 after birth. In a separate study, we followed up to 90 days after birth a larger group if infants. PIVKA-II was found with significantly greater frequency in breast-fed infants receiving no vitamin K than in breast-fed infants receiving 1 mg vitamin K intramuscularly at birth, or in bottle-fed infants without extra vitamin K1. These data form a strong argument for routine vitamin K prophylaxis after birth for all breast-fed infants. The optimum dose and manner of administration require further study.

Plasma abnormal prothrombin (des-gamma-carboxy prothrombin) as a marker of hepatocellular carcinoma

Des-gamma-carboxy prothrombin [DCP], a protein induced by vitamin K absence or antagonist-II and also abbreviated PIVKA-II, was evaluated as a serologic marker for hepatocellular carcinoma (HCC). Its plasma levels were measured by enzyme immunoassay (E-1023) using an anti-DCP monoclonal antibody in 514 patients with various diseases. Of 120 patients with HCC, 76 (63%) had abnormal DCP levels greater than 0.1 arbitrary unit (AU)/ml and 58 (48%) showed levels greater than 0.3 AU/ml. When a diagnostic minimum level of 0.3 AU/ml was applied for DCP, false-positive cases of HCC were virtually eliminated. In some patients with HCC, plasma DCP levels normalized after surgical resection of the tumor. However, they rose again later with recurrence of the disease. The sensitivity of DCP in the diagnosis and monitoring of HCC was increased by serial and simultaneous determinations of alpha-fetoprotein (AFP), because high DCP levels were observed more often in low AFP-producing HCC patients. Elevated plasma DCP levels were not related to low vitamin K concentration in the serum. In fact, in many patients vitamin K administration resulted in only a moderate reduction of DCP levels. These results suggested strongly that DCP was synthesized by the hepatoma cells.

Vitamin K in infancy

Vitamin K has regained paediatric interest due to a recurrence of bleeding caused by deficiency of the vitamin in newborns and young infants. Increasing awareness of these clinical problems, the development of new methods for the detection of vitamin K deficiency and the direct measurement of vitamin K in tissues have stimulated research. Much new data obtained from these studies has proved helpful to the understanding of vitamin K deficiency in infancy. For example low concentrations of vitamin K have been found in fetal and neonatal livers. The implications of these findings with respect to manifest vitamin K deficiency and to new methods for detection of subclinical vitamin K deficiency are discussed. Breast-feeding is a major risk factor for classical haemorrhagic disease of the newborn and for late onset bleeding due to vitamin K deficiency in young infants. The interdependencies between breast-feeding and vitamin K deficiency are discussed on the basis of new data obtained from direct measurement of vitamin K in maternal milk. The review further focuses on pathophysiological concepts of bleeding due to vitamin K deficiency in infancy and current concepts of vitamin K prophylaxis.

Production of abnormal prothrombin (des-gamma-carboxy prothrombin) by hepatocellular carcinoma. A clinical and experimental study

We measured plasma abnormal prothrombin (des-gamma-carboxy prothrombin; DCP) levels in normal subjects and in patients with hepatocellular carcinoma and other various diseases using the enzyme-linked immunosorbent assay developed by Motohara et al. (Pediatr Res 1985; 19: 354-357). Fifty-eight percent of 52 patients with hepatocellular carcinoma had elevated DCP levels; 24 of 28 patients with advanced or moderately advanced hepatocellular carcinoma were positive. By contrast, 50 normal controls, 13 pregnant women and 10 patients with acute hepatitis had normal levels. Three of 55 patients with chronic liver disease, and 6 of 32 patients with other malignancies, showed a slight increase. Thus, increased plasma DCP appears useful for the diagnosis of hepatocellular carcinoma. To elucidate the mechanism for the increase of DCP in hepatocellular carcinoma, we cultured a human hepatoma cell line, huH-2, and measured the levels of this abnormal prothrombin in the medium. The huH-2 cells produced large amounts of DCP in the medium without added vitamin K. It increased in a cell concentration- and time-dependent fashion. These cells produced no detectable amount of DCP in the medium with added vitamin K. Thus, human hepatoma cell line huH-2 produces DCP, and its production is dependent on the amount of vitamin K available in the medium. Des-gamma-carboxy prothrombin may be a useful tumor marker for the diagnosis of hepatocellular carcinoma.

Screening for late neonatal vitamin K deficiency by acarboxyprothrombin in dried blood spots

Acarboxyprothrombin (protein induced by vitamin K absence or antagonist-II (PIVKA-II] concentrations in dried blood spots were determined in 19,029 infants at about 1 month of age as an indicator of vitamin K deficiency. We observed 51 cases with raised blood concentrations of PIVKA-II (greater than 4 AU/ml), nine of whom showed very high concentrations (greater than 20 AU/ml). For infants who did not receive vitamin K prophylaxis at birth, the incidence of the PIVKA-II test yielding positive results was significantly higher in those solely breast fed (0.51%) compared with those fed formula milk (0.18%). Among solely breast fed infants, the incidence of a very high result of the PIVKA-II test was 0.14% in those who had not received vitamin K prophylaxis at birth, 0.04% in those who received 2 mg orally, and 0.03% in those who received 2 mg orally plus a further dose of 2-4 mg orally at 7 days. Thus vitamin K prophylaxis at birth did not completely prevent vitamin K deficiency at 1 month. We administered vitamin K therapeutically to all infants whose PIVKA-II test yielded a positive result at 1 month. Only one infant with a positive result developed late neonatal intracranial haemorrhage.

Vitamin K in the newborn: influence of nutritional factors on acarboxy-prothrombin detectability and factor II and VII clotting activity

The incidence of acarboxy-prothrombin and the clotting activity of factors II and VII were evaluated on the fifth day of life in 183 healthy newborns, who had received no vitamin K prophylaxis. Acarboxy-prothrombin was detected in 93/183 newborns. All acarboxy-prothrombin-negative babies had factors II and VII clotting activities above 25% whereas a great variability was observed in acarboxy-prothrombin-positive babies: 21/93 had factor II and 14/93 had factor VII activities below 25%. Seventy-two of the acarboxy-prothrombin-positive babies had normal factor II and VII clotting times on the fifth day of life. These babies must be suspected to have had vitamin K deficiency on one of the first 4 days, as acarboxy-prothrombin has a 50% disappearance rate of 50 h. Acarboxy-prothrombin was mainly observed in breast-fed infants (84/122) and only rarely detectable in infants receiving supplementary (7/44) or exclusive formula feeding (2/17). The type of milk feeding however might be less important for the babies' vitamin K supply than the actual milk intake. All acarboxy-prothrombin-positive babies had received small amounts of milk on the first 4 days of life. In those with low factor II and VII clotting activities the milk intake was low throughout the first 4 days of life, whereas babies with acarboxy-prothrombin and and normal clotting activities had increased their milk intake to more than 100 ml on the third and fourth day of life. Recommendations for vitamin K prophylaxis in newborns should be given with regard to the feeding on the first days of life.

The placental transport of [3H]vitamin K1 in rats

In this paper we describe the placental transport of [3H]vitamin K1 in pregnant rats during the first 24 h after the oral administration of the vitamin. Vitamin K1 in the fetal livers ranged from 0.13% (3 h) to 2% (24 h) of the values found in the corresponding maternal livers. In spite of the low placental transfer of vitamin K, we found no accumulation of coagulation factor precursors in the fetal rat liver microsomes as could be expected in vitamin K deficiency. Moreover, we could not demonstrate any difference between adult and fetal rat liver microsomes with regard to the sensitivity for warfarin. From these results we conclude that a substantial placental barrier exists for the transport of pharmacological amounts of vitamin K1 but that under physiological conditions sufficient vitamin K1 appears to be present in the fetal liver to ensure a full carboxylation reaction. The vitamin K-dependent carboxylase activity rate of adult and fetal rat liver microsomes was comparable, indicating that the newborn rat has an adequate carboxylating system.

Protein C levels in infancy and early childhood. Influence of breast feeding

Protein C antigen levels were measured in the plasma of healthy full term infants by electroimmunoassay. During the first three months of life (on day four, at one month, two months and three months of age) protein C antigen levels were compared in breast-fed and bottle-fed infants. None of the two groups of infants received vitamin K at birth. Only at the age of three months there was a significant difference between the groups. Unexpectedly infants, who were breast-fed, had a higher protein C level at three months of age. Levels were also measured in 15 healthy children between one and three years of age. The antigen levels increase with age to reach adult values at about three years of age.

Vitamin K deficiency in the newborn infant: prevalence and perinatal risk factors

The prevalence of vitamin K deficiency in newborn infants and the influence of perinatal risk factors were studied prospectively in 934 infants. A noncarboxylated prothrombin assay to detect proteins induced in vitamin K absence (PIVKA-II) was used to determine the presence of vitamin K deficiency; of 934 cord blood samples assayed, 2.9% were positive for PIVKA-II (0.015 to 0.15 U/ml). All infants found to have detectable PIVKA-II were born at term. The number of infants positive for PIVKA-II was greater in the group small for gestational age (7.4%) than in those appropriate (2.7%) or large (3.1%) for gestational age. Nine categories of perinatal risk groups were defined: however, the majority of infants who were PIVKA-II positive (63%) were normal. All infants received prophylactic vitamin K, and no infant with PIVKA-II in the cord sample subsequently had clinical bleeding. In two patients the rate of 50% disappearance of PIVKA-II after vitamin K administration approximated 70 hours. Two PIVKA-II positive patients with active bleeding or disseminated intravascular coagulation had an accelerated disappearance of 20 to 40 hours. The long disappearance time of PIVKA-II in a steady state may allow detection of vitamin K deficiency despite administration of vitamin K. The majority of cases of neonatal vitamin K deficiency occurred in normal newborn infants. Therefore, all infants should receive prophylactic vitamin K at birth.

Effect of vitamin K administration on acarboxy prothrombin (PIVKA-II) levels in newborns

PIVKA-II (protein induced by vitamin K absence or antagonist-II) was measured in two groups of newborns, one group being given 5 mg vitamin K at birth and the other untreated. The untreated group had a significantly higher proportion of PIVKA-II positive babies at 3 and 5 days of age than did the treated group. When vitamin K was administered to newborn babies whose normotest levels were less than 30%, it was found that the higher the pre-treatment PIVKA-II levels the greater the response to vitamin K, as monitored by the normotest. Thus PIVKA-II levels might be more useful than a coagulation test, since the low activity of vitamin K dependent coagulation factors sometimes reflects not vitamin K deficiency but impaired production of these factors because of immaturity. The findings support the view that vitamin K given prophylactically at birth will help to prevent neonatal bleeding.