Effect of administration of a single dose of testosterone oenanthate on constituents of human seminal plasma and serum gonadotropins

Testosterone oenanthate was administered intramuscularly in six infertile men with oligozoospermia and its effects on serum gonadotropins and some constituents in the seminal plasma were studied. One week after injection the mean serum FSH level was decreased to about 50%. Serum LH levels did not change. The mean ornithine decarboxylase activity in human semen was increased by 100% after the testosterone administration. The androgen dependent nature of ODC, fructose and sialic acid have been demonstrated.

Some influences on the ESR and the fibrinogen level in healthy subjects

In healthy subjects the ESR is higher in women than in men, and in both sexes a rise with age occurs. It is well established that pathological elevation of the ESR may be due to elevation of the fibrinogen level. The present study has shown that in normal subjects the ESR correlates not only inversely with the haemoglobin level but also directly with the fibrinogen level. These two factors together explain the difference in ESR between men and women, and the major part of the age-related increase in the ESR. Fibrinogen levels were found to be significantly higher in male smokers than male non-smokers, and in women were inversely correlated with alcohol consumption; despite this the ESR did not differ in smokers and non-smokers, nor was it related to alcohol intake. Oral contraceptive intake influenced neither the fibrinogen level nor the ESR. The correlation of ESR and fibrinogen concentration in healthy subjects suggests that physiological variation in the ESR is determined by the fibrinogen concentration as well as the haemoglobin level.

Studies in sow reproduction: 5. The effect of lactation length of the so w on the subsequent embryonic development

Forty-five female pigs (sows) were allocated at random to one of three lactation lengths: 7 days, 21 days, 42 days. All sows were remated at the first post-weaning oestrus and were slaughtered at 20 days post coitum. The reproductive tracts were removed, dissected and examined. Ovulation rates as determined by luteal count were similar for all three groups, but the number of viable embryos decreased significantly (P < 0·05) from 13·0 for the 42-day lactation group to 9·2 for the 7-day lactation group. This difference was reflected in a significant (P < 0·01) reduction in the percentage embryo survival rate as lactation length was reduced. Uterine lengths for the 7-day lactation group were significantly (P < 0·05) shorter than the other two groups. Six sows in each treatment group were blood sampled: at weaning, at remating, at 2 days post-mating, at 10 days post-mating and at 20 days post-mating. The plasma samples obtained were assayed for progesterone. No differences were observed between treatment groups for plasma progesterone concentration at any of the sampling times. It is concluded that the reduction of the litter size at the next farrowing following a short lactation length is largely a result of increased embryo death in the first 20 days of gestation.

A comparison of hemodynamic data derived by pulmonary artery flotation catheter and the esophageal Doppler monitor in preeclampsia

OBJECTIVE

This study was undertaken to compare hemodynamic data derived with the esophageal Doppler monitor against those obtained with a pulmonary artery flotation catheter in women with complicated preeclampsia.

STUDY DESIGN

Seventeen women with severe preeclampsia who had a pulmonary artery flotation catheter placed for clinical indications also had an esophageal Doppler monitor inserted. Hemodynamic data were recorded on 2 occasions separated by several hours with both the pulmonary artery flotation catheter and the esophageal Doppler monitor simultaneously.

RESULTS

The esophageal Doppler monitor underestimated cardiac output by 36% +/- 14% (mean +/- SD). The esophageal Doppler monitor accurately estimated cardiac output in 3 women >40 years old, whereas in the remaining women (all <35 years old) the esophageal Doppler monitor underestimated cardiac output by 38% +/- 11%. The esophageal Doppler monitor accurately reflected changes in cardiac output with time when compared with the pulmonary artery flotation catheter.

CONCLUSION

In women with preeclampsia the esophageal Doppler monitor consistently underestimated cardiac output by approximately 40%. It is not known whether the apparent increase in accuracy among the women >40 years old arose by chance or reflected a real improvement in performance. The esophageal Doppler monitor accurately reflected the direction and magnitude of the changes in cardiac output with time.

Assessment of different sources of variation in the antibody responses to specific malaria antigens in children in Papua New Guinea

BACKGROUND

A potential problem for malaria vaccine development and testing is between-host variation in antibody responses to specific malaria antigens. Previous work in adults in an area highly endemic for Plasmodium falciparum in Papua New Guinea found that genetic regulation partly explained heterogeneity in responsiveness. We have now assessed the relative contributions of environmental and genetic factors in total IgG responses to specific malaria antigens in children, and quantified temporal variation within individuals of total IgG responses.

METHODS

Total IgG responses against schizont extract, merozoite surface protein-1, merozoite surface protein-2, ring-infected erythrocyte surface antigen, and SPf66 were measured by ELISA. Variance component analysis was used to estimate the variation explained by genetic and environmental factors in these antibody responses. Intra- and inter-class correlations of antibody responses within relative pairs were estimated. We adjusted for age, P. falciparum density, sex and village differences either within or prior to the analysis.

RESULTS

For all malaria antigens, temporal variation in the total IgG response was the predominant source of variation. There was substantial familial aggregation of all IgG responses, but it remained unclear how much this clustering was attributable to genetic factors and how much to a common environment in the household. The remaining variance, which could not be explained by either of the above, was very small for most of the antigens.

CONCLUSIONS

Temporal variation and clustering of immune responses to specific malaria antigens need to be taken into account when planning, conducting and interpreting immuno-epidemiological and vaccine studies.

Metabolic and fibrinolytic response to changed insulin sensitivity in users of oral contraceptives

The fundamental role of insulin resistance for metabolic changes linked to cardiovascular disease and type 2 diabetes is increasingly recognized. Oral contraceptives (OC) may affect insulin sensitivity, and a detailed characterization hereof, as well as the secondary effects on related metabolic systems, are relevant in the evaluation of the risk of developing vascular disorders or diabetes in OC users. We studied insulin sensitivity index (S(I)), glucose effectiveness (S(g)), and insulin response in young, healthy women by frequently sampled intravenous glucose tolerance tests before and after randomization to 6 months of treatment with ethinyl estradiol in triphasic combination with norgestimate (n = 17) or gestodene (n = 20). Measurements of fasting triglycerides and antigen concentrations of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) were also included. Both compounds increased fasting plasma insulin and reduced S(i) but did not affect S(g). The relationships between S(i) and insulin response were unchanged. No consistent correlation between insulin sensitivity and triglycerides, t-PA, or PAI-1 were demonstrated before or during treatment. We conclude that the treatments were followed by a compensated decrease in insulin sensitivity that was unrelated to changes in triglycerides, t-PA, or PAI-1 antigen.

Effects of oral contraceptives on hemostasis and thrombosis

OBJECTIVE

The object of the study was to determine the effects of oral contraceptives on blood coagulation, in particular on the protein C pathway.

STUDY DESIGN

Plasma samples from healthy men, from healthy female users and nonusers of oral contraceptives, and from heterozygous and homozygous male and female carriers of the factor V Leiden mutation (some of whom used oral contraceptives) were tested for their sensitivity to activated protein C by means of a new activated protein C resistance test developed in our laboratory. This assay is based on measurement of the effect of activated protein C on the endogenous thrombin potential, the time integral of thrombin generation initiated in plasma through the extrinsic coagulation pathway.

RESULTS

The normalized activated protein C sensitivity ratio ([ETP+APC/ETP-APC]plasma/[ETP+APC/ETP-APC]normal plasma, where ETP is endogenous thrombin potential, +APC is with activated protein C, and -APC is without activated protein C) of men was lower than that of healthy female nonusers of oral contraceptives. The normalized activated protein C sensitivity ratio of the users of oral contraceptives was significantly higher than that of nonusers of oral contraceptives. The normalized activated protein C sensitivity ratio of women who were using oral contraceptives with third-generation progestogens was higher than that of users of oral contraceptives with second-generation progestogens. Furthermore, the normalized activated protein C sensitivity ratio of 80% of the users of third-generation preparations fell within the 5th to 95th percentile of the normalized activated protein C sensitivity ratio of female carriers of factor V Leiden, a mutation that is associated with hereditary resistance to activated protein C and with an increased risk of venous thromboembolism.

CONCLUSION

Acquired activated protein C resistance may explain the increased risk of venous thromboembolism among users of oral contraceptives reported in epidemiologic studies and the higher risk of venous thromboembolism among users of oral contraceptives with third- versus second-generation progestogens.

Hemostatic effects of smoking and oral contraceptive use

This review addresses current knowledge of the effects of lower dose oral contraceptives (containing 35, 30, or 20 micrograms of ethinyl estradiol) on hemostasis in smoking and nonsmoking women. Evidence suggests that formulations containing 30 and 35 micrograms ethinyl estradiol induce a significant activation of coagulation, whereas oral contraceptive preparations with 20 micrograms ethinyl estradiol appear to have a negligible effect or no effect. In nonsmokers who take oral contraceptives any procoagulatory effects that may occur are counterbalanced by fibrinolytic effects. In smokers, however, compensatory fibrinolytic effects to offset the procoagulatory effects seen with 30-micrograms ethinyl estradiol oral contraceptive formulations are absent, shifting the hemostatic profile toward a hypercoagulable state. This suggests that a formulation with the lowest dose of ethinyl estradiol may be most suitable for smokers who wish to use this form of contraception.

Decreased plasma tissue factor pathway inhibitor in women taking combined oral contraceptives

Use of combined oral contraceptives (OC) is associated with a significant risk of thrombosis. The mechanisms of this effect are not clearly defined. Tissue factor pathway inhibitor (TFPI) is a circulating anti-coagulant that inhibits the earliest steps in activation of the extrinsic coagulation pathway. It plays a central role in control of coagulation but its contribution to the thrombotic risk associated with OC has not been assessed. Plasma TFPI antigen and activity, factor VIIa, prothrombin fragments 1&2, von Willebrand antigen, fibrinogen, and low density lipoprotein cholesterol were measured by standard assays in women taking OC (aged 16 to 45 years, n = 40) and age-matched women not taking OC (controls, n = 40). Plasma TFPI antigen did not vary significantly across the menstrual cycle in controls. Women on OC had a 25% reduction in plasma TFPI antigen (median 51.0 ng/ml; 95% confidence intervals [CI] 37.5 to 85.5; control 68.0 ng/ml, CI 61.0 to 95.0; P < 0.001) and a 29% reduction in TFPI activity (78.5 U/ml, CI 57.5 to 107.5; control 111.0 U/ml, CI 79.5 to 171.0; P < 0.001) compared to controls. Plasma factor VIIa activity and prothrombin fragments 1&2 were also significantly increased in women using OC (both P < 0.001), indicating activation of the extrinsic coagulation pathway. These results demonstrate that normal cyclic variations in estrogen and/or progesterone do not significantly alter plasma TFPI levels. However, estrogens and/or progestogens in OC result in activation of the extrinsic coagulation pathway and significantly reduce plasma TFPI, its major circulating inhibitor. Reduced plasma TFPI levels may underlie the thrombotic effects of OC.

Resistance to activated protein C in women using oral contraceptives

Resistance to activated protein C (APC resistance) is an important and common risk factor for deep vein thrombosis. The majority of patients with APC resistance carry a mutation on the factor V gene at nucleotide position 1691 (G/A), called factor V Leiden mutation. Besides the factor V Leiden mutation several acquired risk factors like lupus anticoagulant, elevated levels of acute phase proteins (increased plasma levels of factor VIII and fibrinogen), pregnancy, or the use of oral contraceptives are known to induce APC resistance in plasma. We studied the effect of oral contraceptives (OC) on hemostasis variables known to be risk factors for venous thromboembolism, especially looking for acquired APC resistance and the plasmatic factors of the protein C system. We studied 821 women, who were randomly selected and enrolled in the BATER- cohort study (Bavarian Thromboembolic Risk Study), which was carried out in Bavaria (Germany) from 1996 to 1997. Current use of any OC type compared with noncurrent use showed a significantly impaired response to APC. There was no difference in APC response among women currently using OCs of different generations. Coagulation factor VIII was the only factor of the protein C pathway that was not altered under OC use. All other plasmatic factors of the protein C system changed in the expected range as described before. On the other hand, coagulation factor VIII was the only factor of the protein C system which negatively correlated with the APC response in the assays applied. Thus, APC resistance is significantly lower in OC users than in nonusers but cannot be attributed to increased factor VIII levels. Whether a decreased response to APC in OC users is of clinical relevance has to be proven in further studies.

Hemostatic effects of oral contraceptives in women who developed deep-vein thrombosis while using oral contraceptives

OBJECTIVE

Comparison of the effect of oral contraceptives on hemostatic variables in venous thrombosis patients (thrombosis while using oral contraceptives) with the effect in healthy control subjects. Our aim was to assess whether some of these effects were more pronounced in women who had suffered thrombosis, i.e., whether these were "hemostatic hyperresponders".

STUDY DESIGN

A population-based case-control study, the Leiden Thrombophilia Study.

MATERIALS AND METHODS

We investigated 99 pre-menopausal women, age 15-49 years, who had used oral contraceptives at the time of a first, objectively confirmed episode of deep-vein thrombosis. They were not pregnant, nor in puerperium, nor had had a recent miscarriage, and were not using injectable progestogens, nor suffering from inherited coagulation defects. The median time between occurrence of deep-vein thrombosis and venepuncture was 18 months, and 30 of the 99 women were still using oral contraceptives, while 69 had discontinued oral contraceptive use. In addition, a group of 153 control women (54 of them were oral contraceptive users and 99 were non-users) were studied. The following hemostatic variables were measured: APTT, factor VII, factor VIII, factor XII, fibrinogen, prothrombin, total antithrombin, normalised activated protein C sensitivity ratio (n-APC-sr), protein C, protein S and free protein S.

RESULTS

We found marked and significant effects of oral contraceptive use on the levels of several clotting factors, with an increase in factor VII, factor XII, protein C and a decrease in antithrombin, n-APC-sr and protein S. Less marked effects that were non-significant or only significant in either patients or controls, were an increase in factor VIII, fibrinogen and prothrombin and a decrease in the APTT and free protein S. In the former thrombosis patients several of these effects of oral contraceptives were more pronounced than in healthy women: specifically on factor VII, antithrombin, n-APC-sr and protein C.

CONCLUSIONS

Our results of the effects of oral contraceptives generally confirm previous reports in healthy volunteers. Our data also show that in former deep-vein thrombosis patients these effects are more pronounced. Apparently some women become "high hemostatic responders" when exposed to oral contraceptives, and they may be the women most vulnerable to its thrombogenic effects.

Determinants of progression of HIV infection in a Greek hemophilia cohort followed for up to 16 years after seroconversion

Our objectives are to describe the progression of HIV disease and to assess the influence of hemophilia-related variables, age at infection, and antibodies to cytomegalovirus infection (anti-CMV) in a Greek cohort of 158 HIV-1-positive hemophilic men, who received prospective follow-up for up to 16 years after infection. A total of 79 patients had died, representing a cumulative progression rate of 72.4% (95% confidence interval [CI], 56.6-83.3). A significant proportion of the mortality (30%) resulted from conditions not formally related to AIDS, with liver failure and cerebral hemorrhage predominant. At 16 years after seroconversion, 66 patients had developed clinical AIDS, a cumulative progression rate of 58.2% (95% CI, 47.1%-86.3%) whereas 15 years after infection 81.5% (95% CI, 74.2%-87.9%) of the patients had AIDS or a CD4 cell count <200 cells/mm3. Hemophilia-related variables or presence of anti-CMV were not significantly associated with disease progression. Age at infection was a strong prognostic factor for all three endpoints. Appropriate modeling showed a nonlinear age effect, with a steeper increase of relative hazard for patients >40 years of age at seroconversion. The age effect remained significant even after controlling for current CD4 cell count. Further investigation is required to elucidate the mechanisms of the age effect and the contribution of HCV coinfection on the disease progression.

Effects on hemostatic variables of desogestrel- and gestodene-containing oral contraceptives in comparison with levonorgestrel-containing oral contraceptives: a review

In some studies third-generation oral contraceptives have been reported to be associated with a higher risk of venous thromboembolism than are second-generation oral contraceptives, whereas recent, more refined studies have not confirmed this. The reasons for the alleged differences are under discussion, and differential effects on hemostasis have been proposed. Eighteen studies comparing second- and third-generation oral contraceptives with respect to their effects on hemostasis were analyzed. Significant changes from baseline were reported for many variables with both second- and third-generation oral contraceptives without significant between-group differences. Also, in a combined analysis of nonsignificant changes, no consistent pattern of change emerged for any marker, with the exception of higher factor VII levels associated with third-generation oral contraceptives. However, factor VII is not related to venous thromboembolism risk. In addition, 1 cross-sectional study with an unvalidated assay reported a higher ratio of activated protein C sensitivity with third-generation oral contraceptives. Only 2 components of the hemostatic system (factor VII and activated protein C sensitivity ratio) emerged as potentially differentially affected by second- and third-generation oral contraceptives; the association with venous thromboembolism risk is questionable in the former case and unknown in the latter.

Urbanization and childhood leukaemia in Taiwan

BACKGROUND

In the 1980s socioeconomic development was dramatically rapid in the urbanized municipalities of Taiwan due to a prospering economy. This study addressed the question: Could differences in the incidence of childhood leukaemia (age <15) be demonstrated between urban and rural communities in Taiwan between 1981 and 1990?

METHODS

The log-linear regression model was used to assess the effects of age, level of urbanization, and calendar year on the variation of childhood leukaemia incidence rates between 1981 and 1990.

RESULTS

Between 1981 and 1990, the overall incidence rate of childhood leukaemia increased by 20% (rate ratio (RR) = 1.2, 95% CI: 1.0-1.5). As compared to rural areas, metropolitan regions showed a significantly higher incidence rate during the study period (RR = 1.3, 95% CI: 1.1-1.6). This urban-rural difference was particularly notable among children <5 years old (RR = 1.5, 95% CI: 1.2-1.9). Dose-response analysis further indicated that risk of childhood leukaemia was monotonically associated with levels of urbanization. The significant gradient in the risk of childhood leukaemia with urbanization was contributed solely by children in the 0-4 years age group.

CONCLUSIONS

We noticed a relationship between urbanization and risk of leukaemia in children. Because of a dramatic influx of people into metropolitan areas during the 1980s, our findings may have provided support for the putative association between 'population mixing' or 'population density' and risk of childhood leukaemia. Whether such association can be attributable to virus infection or other aetiologically related leukemogens warrants further investigations.

Resistance to activated protein C, highly prevalent amongst users of oral contraceptives with venous thromboembolism

OBJECTIVE

Inherited resistance to activated protein C (APC resistance), which is caused by a single point mutation in the factor V gene, is a frequent risk factor for venous thromboembolism. The aim of this study was to determine the prevalence of APC resistance and other coagulation disorders in fertile women with venous thromboembolism and also the risk factors these women had been exposed to in connection with thromboembolic events.

DESIGN

A retrospective, case-control study of 36 month duration.

SETTING

The study was carried out at Blekinge Hospital, Karlskrona, Sweden.

SUBJECTS

The study population comprised 27 fertile women age 16-47 years with thromboembolic complications, referred to the department of Internal Medicine at Blekinge Hospital in Karlskrona during a 36-month period.

RESULTS

APC resistance was found in 10 out of 27 women. APC resistance was associated with treatment with oral contraceptives in five out of six women and with pregnancy in one of seven women. All women with resistance to APC developed venous thrombosis in association with a predisposing situation (risk situation) such as surgery, trauma, immobilization, pregnancy, inflammatory state or the use of oral contraceptives. Amongst women not resistant to APC, all but one developed thrombosis in connection with a risk situation.

CONCLUSION

APC resistance was found to be highly prevalent amongst fertile women with a history of thromboembolic complication occurring during their use of oral contraceptives.

High risk of cerebral-vein thrombosis in carriers of a prothrombin-gene mutation and in users of oral contraceptives

BACKGROUND

Idiopathic cerebral-vein thrombosis can cause serious neurologic disability. We evaluated risk factors for this disorder, including genetic risk factors (mutations in the genes encoding factor V and prothrombin) and nongenetic risk factors (such as the use of oral contraceptive agents). We compared the prevalence of these risk factors in 40 patients with cerebral-vein thrombosis, 80 patients with deep-vein thrombosis of the lower extremities, and 120 healthy controls. The G1691A mutation in the factor V gene and the G20210A prothrombin-gene mutation, which are established genetic risk factors for venous thrombosis, were studied. We also assessed the use of oral contraceptives and other risk factors for thrombosis.

RESULTS

The prevalence of the prothrombin-gene mutation was higher in patients with cerebral-vein thrombosis (20 percent) than in healthy controls (3 percent; odds ratio, 10.2; 95 percent confidence interval, 2.3 to 31.0) and was similar to that in patients with deep-vein thrombosis (18 percent). Similar results were obtained for the mutation in the factor V gene. The use of oral contraceptives was more frequent among women with cerebral-vein thrombosis (96 percent) than among controls (32 percent; odds ratio, 22.1; 95 percent confidence interval, 5.9 to 84.2) and among those with deep-vein thrombosis (61 percent; odds ratio, 4.4; 95 percent confidence interval, 1.1 to 17.8). For women who were taking oral contraceptives and who also had the prothrombin-gene mutation (seven patients with cerebral-vein thrombosis but only one control), the odds ratio for cerebral-vein thrombosis rose to 149.3 (95 percent confidence interval, 31.0 to 711.0).

CONCLUSIONS

Mutations in the prothrombin gene and the factor V gene are associated with cerebral-vein thrombosis. The use of oral contraceptives is also strongly and independently associated with the disorder. The presence of both the prothrombin-gene mutation and oral-contraceptive use raises the risk of cerebral-vein thrombosis further.

Correlation of coagulation abnormalities with clinical outcome in neonates of mothers with pregnancy induced hypertension

Abnormalities in coagulation profile were correlated with clinical outcome in neonates (n = 30) of mothers with pregnancy induced hypertension (PIH). Same number of neonates born to normotensive mothers was taken as control. Significant correlation was observed between decreasing gestational age and alterations in all coagulation parameters. Higher incidence of prematurity, hyperbilirubinaemia and significant prolongation in partial thromboplastin time with kaolin (PTTK) and thrombin time (TT) values were observed with increasing severity of PIH. Incidence of disseminated intravascular coagulation (DIC) was higher in preterm neonates than in term neonates.

Hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome: a review of diagnosis and management

Hemolysis, elevated liver enzymes, and low platelet (HELLP) syndrome is a form of severe preeclampsia that threatens the gravida and her fetus. In this report, the diagnostic criteria and maternal and fetal risks of HELLP are defined. Prompt recognition and treatment in tertiary centers is emphasized, because the prognosis can be adversely affected by delayed or less than optimal diagnosis and treatment. Management guidelines are offered for treating this disorder. The potential roles of corticosteroids, plasmapheresis, and expectant management are critically evaluated. Subsequent pregnancy outcome, contraception, and preventative strategies are considered.

Humoral immunity status in neonates born to pre-eclamptic toxaemia mothers

A prospective study on 90 neonates born to age matched normal mothers (set I) and mothers (set II) with pre-eclamptic toxaemia (PET) was undertaken to assess and compare the humoral immunity status of the neonates. All of them had normal vaginal delivery. IgG, IgA and IgM were estimated by radial immunodiffusion technique from cord blood of neonates. It was observed that IgA and IgM levels were insignificant in the cord blood. IgG level was low in normal birth weight (NBW) neonates born to PET mothers, when compared to that of NBW neonates born to normal mothers. Again low birth weight (LBW) babies of both the sets showed lower values of IgG than that of NBW babies. Apgar scoring showed direct relationship with IgG levels e.g., higher the Apgar score higher the level of IgG. Thus the IgG level was directly related to the birth weight of the neonates of the respective sets as well as with the Apgar scoring of the neonates.

Metabolic interrelationships, cardiovascular disease, and sex steroids

Future studies of the pharmacodynamics of oral contraceptives should encompass interactions between various areas of physiology rather than concentrate on single metabolic processes. Changes in one area of metabolism may affect other areas. Insulin plays a central role in metabolic control and, in addition to profound effects on carbohydrate and lipid metabolism, also affects the hematological system. Insulin has been proposed as a major physiological regulator of plasminogen activator inhibitor, and hyperinsulinemia is associated with increased blood coagulability and decreased fibrinoloysis. There is a close relationship between insulin and triglyceride metabolism, and this may affect factor VII activity in blood. There are many interactions between lipid metabolism and hematological factors. The apoprotein of lipoprotein (a) is structurally similar to plasminogen. Tissue factor pathway inhibitor, a regulator of coagulation, circulates in blood bound to LDL and HDL. Some fatty acids may act as a contact surface for activation of hematological factors. Dietary factors also need to be considered. Changes not only in the quantity but also in the composition of dietary fat influence lipid metabolism and also blood levels of a number of hematological factors. Other aspects of pharmacodynamic studies that require consideration and other factors that affect metabolic interrelationships are discussed.

Mannose binding protein deficiency is not associated with malaria, hepatitis B carriage nor tuberculosis in Africans

We retrospectively studied MBP genotypes in patients with malaria, tuberculosis (TB), and persistent hepatitis B virus (HBV) carriage, in clinics and hospitals in The Gambia. Children under 10 years with cerebral malaria and/or severe malarial anaemia, were compared with children with symptomatic, mild malaria, and controls of the same age and ethnicity. Adult TB cases with smear-positive pulmonary TB were compared with healthy blood donors from the same ethnic groups. Malaria cases and controls were tested for hepatitis B core antibody (anti-HBc) and surface antigen (HBsAg). TB patients were tested for HIV antibodies. Genotyping used sequence-specific oligonucleotide analysis to identify MBP variant alleles. Overall, 46% (944/2041) of patients and controls were homozygous for the wild-type MBP allele, 45% (922/2041) were carriers of a single variant allele and 8.6% (175/2041) had two variant alleles. Neither homozygotes nor heterozygotes for MBP variants were at increased risk of clinical malaria, persistent HBV carriage or TB. The most common mutation in Africans, the codon 57 variant allele, was weakly associated with resistance to TB (221/794 in TB cases and 276/844 in controls, p = 0.037). MBP deficiency is not a significant risk factor for persistent HBV, severe malaria nor pulmonary TB in West Africa.

[Late effects of sterilization in women]

Sterilization affects measurably the circulation and the functioning of the ovaries, but further studies are required to estimate the clinical meaning of the change.

alpha+-Thalassemia protects children against disease caused by other infections as well as malaria

In the South West Pacific region, the striking geographical correlation between the frequency of alpha+-thalassemia and the endemicity of Plasmodium falciparum suggests that this hemoglobinopathy provides a selective advantage against malaria. In Vanuatu, paradoxically, alpha+-thalassemia increases the incidence of contracting mild malaria in the first 2 years of life, but severe disease was too uncommon to assess adequately. Therefore, we undertook a prospective case-control study of children with severe malaria on the north coast of Papua New Guinea, where malaria transmission is intense and alpha+-thalassemia affects more than 90% of the population. Compared with normal children, the risk of having severe malaria was 0.40 (95% confidence interval 0.22-0.74) in alpha+-thalassemia homozygotes and 0.66 (0.37-1.20) in heterozygotes. Unexpectedly, the risk of hospital admission with infections other than malaria also was reduced to a similar degree in homozygous (0. 36; 95% confidence interval 0.22-0.60) and heterozygous (0.63; 0. 38-1.07) children. This clinical study demonstrates that a malaria resistance gene protects against disease caused by infections other than malaria. The mechanism of the remarkable protective effect of alpha+-thalassemia against severe childhood disease remains unclear but must encompass the clear interaction between this hemoglobinopathy and both malarial and nonmalarial infections.

Selective screening for the Factor V Leiden mutation: is it advisable prior to the prescription of oral contraceptives?

The cumulative thrombotic risk of Factor V (FV) Leiden and oral contraceptives (OC) recommends screening for the mutation. Assuming that a family history of thrombosis increases the patient's likelihood of bearing FV Leiden, a selective rather than universal screening would be performed. We studied the utility of a family history of thrombosis for screening of FV Leiden before prescription of OC and, furthermore, the utility of screening even if oral contraception is favoured. 101 patients who had their first and single thromboembolic event while using OC were interviewed. 609 women without any history of thromboembolism recruited by gynecologists completed a standard questionnaire. 101 of these women, age-matched and currently using OC, were selected for a case-control study. Regarding patients with previous thromboembolism, a family history in a first-degree relative had a positive predictive value (PPV) of only 14% for FV Leiden. A PPV of 12% was calculated by investigating the 609 thrombosis-free women. Inherited FV Leiden (odds ratio = 4.9) and acquired risk factors (odds ratio = 10.1) were both found to be the most prominent, but independent additional risks. Nevertheless, FV Leiden carriers, both heterozygotes and homozygotes, did not suffer earlier from thromboembolism than patients without the mutation. In conclusion, family history is an unreliable criterion to detect FV Leiden carriers. Screening for factor V Leiden can be worthwhile even if the advantages of oral contraception are higher assessed than the thrombotic risk. Affected women knowing about their additional risk could contribute to the prevention of thrombosis in risk situations.

Factor V Leiden mutation and the risks for thromboembolic disease: a clinical perspective

BACKGROUND

A single point mutation in the gene coding for coagulation factor V results in a form of factor Va that is resistant to degradation by activated protein C and leads to a relative hypercoagulable state. This mutation, factor V Leiden, is found in 4% to 6% of the U.S. population.

PURPOSE

To review clinical data on factor V Leiden mutation, with emphasis on prevalence of and risks for thromboembolism and implications for screening and management.

DATA SOURCES

A MEDLINE search of the English-language literature published between 1993 and April 1997 and an extensive bibliography review.

STUDY SELECTION

Case-control and prospective cohort studies were reviewed if clinical features of thromboembolic disease associated with factor V Leiden mutation or resistance to activated protein C were presented. Original research articles were reviewed if they addressed the identification of the laboratory abnormality of activated protein C or factor V Leiden mutation. Case reports and case series were reviewed when no analytic data were available.

DATA EXTRACTION

Review of the identified articles.

DATA SYNTHESIS

Factor V Leiden mutation is associated with three- to sixfold increases in risks for primary and recurrent venous thromboembolism, especially in patients without transient risk factors, such as surgery or trauma. Risks for venous thromboembolism in genetically affected persons are substantially higher among patients with coexistent predispositions for thrombosis, such as advanced age, use of oral contraceptives, hyperhomocystinemia, and deficiencies of protein C and protein S. Factor V Leiden mutation does not seem to increase risks for arterial thrombosis. Whether patients with the mutation would benefit from more intense or prolonged anticoagulation is unknown.

CONCLUSIONS

The presence of factor V Leiden mutation predisposes patients to venous thromboembolism, but screening for this disorder is of uncertain utility. Decisions about whether to screen for the mutation will depend on the results of clinical trials designed to evaluate the benefit-to-risk ratio of long-term anticoagulation in the secondary prevention of venous thromboembolism in patients with resistance to activated protein C.

Third-generation oral contraceptive and deep venous thrombosis: from epidemiologic controversy to new insight in coagulation

Four epidemiologic studies showed a twofold increase in risk of deep venous thrombosis with the use of oral contraceptives containing third-generation progestins, relative to second-generation products. These findings have been strongly debated ever since, and new studies have been added. In the current article we examine whether the findings can be explained by potential biases or other shortcomings of the epidemiologic studies. We conclude that complete certainty cannot exist but that the most rational conclusion from the epidemiologic findings and their discussion is that an increased risk of deep venous thrombosis with third-generation contraceptives is likely, especially in first-time and young users. The controversy has recently led to new insights in coagulation: Women who use third-generation contraceptives acquire a resistance to the blood's own anticoagulation system, similar to the activated protein C resistance that is seen in persons who carry the factor V Leiden mutation but different from that in women using second-generation contraceptives.

[Contraceptive agents and risk of thrombosis]

In the late sixties and seventies, publications of the Royal College of General Practitioners in England reported that in women using oral contraceptiva the incidence of venous thromboembolism is increased by two to four fold. Moreover, it was demonstrated, that these alterations in coagulation were induced by ethinylestradiol in a dose dependent manner. Following these findings, its dosage was lowered from more than 100 micrograms to 20-30 micrograms per day. More recently, the role of gestagens in inducing thrombosis has also been debated. Different authors observed an increased risk for venous thromboembolism in women using third generation pills containing gestoden or desogestrel compared with users of second generation levonorgestrel contraceptiva. These reports have generated a lot of concern and fear in the patients as well as doctors and have led to a drastic fall in the use of oral contraceptives. Due to the unavailability of safe contraceptive alternatives, the number of women experiencing unwanted pregnancy and its complications increased significantly. Indeed, direct proof for the role of gestagens in inducing thromboembolism is still lacking as the protocol designs of these studies do not allow us to infer whether the effects are due to the gestagens or to confounding variables. Hence, the discussions were beneficial for clinicians to remember the importance of checking the patient for individual and family risks for thrombosis before handling out a pill prescription.

Haemostatic changes and the oral contraceptive pill

Oral contraceptives have been linked to an increased incidence of thrombovascular disease. This may be mediated by their effects on the haemostatic system. An increase in the activity of coagulation Factors VII, X and fibrinogen occur with pill usage. Increased Factor VII levels are dependent on both the oestrogen and progestogen component of the oral contraceptive. A reduction in antithrombin III levels has also been observed in some but not all studies. Increased fibrinolysis has also been shown in oral contraceptive users which should balance the changes in the coagulation pathway. The increase in fibrinolytic potential is thought to be due to a decrease in the levels of plasminogen activator inhibitor I combined with an increase in the levels of plasminogen; tissue plasminogen activator antigen is decreased in most studies. The increased levels of endpoints of coagulation and fibrinolysis in pill users indicate that enhanced activity of both systems is occurring in vivo. The increased coagulation activity appears to be balanced by the rise in fibrinolytic activity, so preserving haemostatic balance. Enhanced platelet activity has also been shown in women taking oral contraceptives. Thrombus formation can result, however, when local vascular wall damage exists, or when other risk factors for thrombo-embolism, such as older age and smoking, coexist and create a local activation resulting in a thrombus. In these situations, the small differences in levels of coagulation factors in women taking different oral contraceptive formulations may be important. Pills containing the lowest doses of oestrogen (20 micrograms ethinyloestradiol) have shown the least changes in haemostatic factors. The progestogen component of the pill modifies the effect of oestrogen on the haemostatic system.

The pill and thrombosis: epidemiological considerations

The oral contraceptive is one of the most widely taken medications in the healthy population. The clinically important side-effects are venous and arterial thrombosis. Accurate estimates of incidence of these side-effects have proven to be difficult. Diagnostic modalities for thrombosis are sub-optimal and the problems of study methodology, primarily a reliance on non-experimental studies, have limited the ability to define the attributable risk of thrombosis from oral contraception. Pharmacological attempts to further decrease venous thrombotic side-effects by the use of third-generation oral contraceptives have failed. This places a greater emphasis on the selection of patients to help avoid giving medication to those patients with underlying thrombotic risk factors. An example of this approach has been the clear confirmation of the adverse effects of cigarette smoking and arterial thrombosis in oral contraceptive users. At the biochemical level, hypercoagulability testing may be useful. Screening for high-frequency prothrombotic abnormalities, such as the Factor V Leiden genotype, represents an important addition to the process by which patients are selected, and may be prototypic of further advances.

Lactic acidosis and oxygen debt in African children with severe anaemia

A syndrome of severe anaemia (Hb < or = 5 g/dl), particularly severe malarial anaemia (SMA), remains a major cause of childhood mortality in sub-Saharan Africa. We hypothesized that the lactic acidosis which identifies those at the greatest risk of death often represents an oxygen debt incurred as a result of inadequate tissue perfusion. To examine this hypothesis, we measured oxygen consumption (VO2) using a portable metabolic monitor. Blood lactate and acid-base status were also determined. Pre-transfusion data on 44 children (28 with mild symptoms, 7 with respiratory distress and 9 controls) demonstrated very close dependence of VO2 on body surface area (BSA, R2 = 0.86, p < 0.001). After correcting for BSA, no significant differences were observed in mean VO2 values of the three clinical groups, indicating that a critical reduction in oxygen delivery is not the sole explanation for the development of a lactic acidosis and severe symptoms. Nine children (including five of the original 44) were monitored during transfusion. In four of the five with SMA, severe symptoms and severe lactic acidosis, transfusion produced a marked, transient increase in VO2 (maximum 30-41%), with a marked fall in blood lactate and clinical improvement. These data suggest that some children with SMA and respiratory distress accumulate an oxygen debt when a relatively high oxygen demand outstrips supply, this debt being repaid when supply is increased during transfusion. However, in the remaining one of these five children, an increase in VO2 (maximum 20%), was accompanied by a rise in blood lactate and clinical deterioration, suggesting that more pathophysiologically complex mechanisms, which may predominate in some children.

Double-blind, randomized, placebo controlled study on the effects of the monophasic oral contraceptive containing 30 micrograms ethinyl estradiol and 2.00 mg dienogest on the hemostatic system

Forty healthy female volunteers aged between 19 and 35 years (27.3 +/- 4.1 years) with normal menstrual cycles were included in a double-blind, randomized, placebo-controlled study to investigate the influence on the hemostatic system of an oral contraceptive containing 30 micrograms ethinyl estradiol in combination with 2.00 mg dienogest, which is a 19-norprogestin without a 17 alpha-ethinyl group. At baseline and during one treatment cycle, 12 hemostatic parameters were measured on cycle days 7, 14, and 21. The hemostatic parameters were categorized as either procoagulatory, anticoagulatory and profibrinolytic, or antifibrinolytic and indicative of fibrin turnover. Differences between placebo and 30 micrograms ethinyl estradiol and 2.00 mg dienogest of plasma levels of hemostatic parameters on cycle days 21 of the precycle and treatment cycle were chosen as target variables. Prothrombin fragment 1 + 2 (F 1 + 2) was chosen as the main target variable. Equivalence of F 1 + 2 between placebo and active treatment was noted. Among the procoagulatory factors, only factor VII activity was found to be increased over placebo in the active treatment group, but decreased in the placebo group. Protein C activity increased during the treatment with 30 micrograms ethinyl estradiol and 2.00 mg dienogest, and was higher than that of the placebo group in which this parameter decreased during the treatment cycle. There was a corresponding increase in fibrinolytic activity being reflected by higher plasminogen levels in the active treatment group in comparison with placebo. An increase was noted for the fibrinolytic parameter D-dimer. Apart from isolated measurements, the parameters remained in their respective normal ranges. The data combine to suggest that 30 micrograms ethinyl estradiol and 2.00 mg dienogest has a balanced effect on the hemostatic system stimulating both procoagulatory and fibrinolytic activity.

Brazilian report on primary immunodeficiencies in children: 166 cases studied over a follow-up time of 15 years

One hundred sixty-six cases of primary immunodeficiency diseases (PID) (95 males, 71 females), diagnosed according to WHO criteria, have been registered at the Children's Hospital, University of São Paulo, Brazil. The following frequencies were found: predominantly humoral defects, 60.8% (n = 101); T cell defects, 4.9% (n = 8); combined ID, 9.6% (n = 16); phagocyte disorders, 18.7% (n = 31); and complement deficiencies, 6% (n = 10). IgA deficiency was the most frequent disorder (n = 60), followed by transient hypogammaglobulinemia (n = 14), chronic granulomatous disease (n = 14), and X-linked agammaglobulinemia (n = 9). In comparison to other (national) reports, we observed higher relative frequencies of phagocyte and complement deficiencies. Recurrent infections were the cause of death in 12.7%. Allergic symptoms were observed in 41%, mainly in IgA-deficient, hypogammaglobulinemic, or hyper-IgE patients, and autoimmune disorders in 5%, predominantly in IgA and complement deficiencies. Five patients suffered from BCG dissemination; two of them died. This is the first Brazilian report on PID over an observation time of 15 years.