Predictive factors in recurrent spontaneous aborters--a multicenter study

PROBLEM

Compare data from several centers relating to success rates in recurrent spontaneous miscarriage and assess the significance of indicators of subsequent pregnancy loss.

METHOD

Data from 777 couples with unexplained recurrent spontaneous abortion from independent studies at seven centers were analyzed using logistic regression analysis. The following covariates were considered: age of patient, number of previous spontaneous abortions, length of previous abortions history, sub-fertility index (defined as the product of the number of spontaneous abortions and the abortion history), whether a patient was a primary or secondary aborter, and whether a patient had received leukocyte immunotherapy.

RESULTS

There was a highly significant difference between the seven centers in success rates in the subsequent pregnancy and a highly significant association between success rate and each of the following covariates: the number of previous abortions, the length of the previous abortion history and the sub-fertility index. In particular, for each increase of 10 units in the value of the sub-fertility index, up to a value of 30, the odds in favor of a successful pregnancy decreased by a factor of 0.6, i.e., 40%. There was, however, little evidence of an association between the success rate in the subsequent pregnancy and age, parity, or immunization with cells from the husband.

CONCLUSIONS

The sub-fertility index may be a useful measure of likelihood of success in a subsequent pregnancy.

Incidence of antiphospholipid antibodies in patients with monoclonal gammopathy of undetermined significance

The incidence of antiphospholipid antibodies in patients with monoclonal gammopathy of undetermined significance (MGUS) was studied. Antiphospholipid antibodies were measured in the sera of 93 patients (49 women, 44 men; mean age 70 [+/- 21] years) with MGUS by using an enzyme-linked immunosorbent assay (ELISA). The phospholipids tested were cardiolipin (CL), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidylglycerol (PG), phosphatidic acid (PA), phosphatidylcholine (PC), and phosphatidylethanolamine (PE). Positive results were defined as a value higher than the number of multiples of the mean per phospholipid, which included 76 of 80 (95%; 20 age-matched) control individuals. The immunoglobulin-G (IgG) or IgM antiphospholipid antibodies isotype varied among the patients, as did the phospholipid specificity. For IgG, PI was found elevated in 32% of the MGUS samples, whereas the other phospholipid antigens ranged from 9% to 15%. The percentage of patients with IgM antiphospholipid antibodies was higher. The authors observed PS, PI, PA, and PC as positive in 45%, 35%, 25%, and 25% of patients, respectively. Of the 12 sera studied for IgA isotype, three (25%) were positive for PS, six (50%) for CL, and none for PE. Patients with MGUS manifested a significantly higher (P < .01) incidence of antiphospholipid antibodies in their blood than did the control persons. No difference in the incidence of antiphospholipid antibodies was seen between younger and older (age-matched) control patients. No correlation was found between serum levels of immunoglobulins and optical density reading of the blank plates used as ELISA controls.

Characterization of cofactor activity for factor I: cleavage of complement C4 in human syncytiotrophoblast microvilli

To coexist with complement, human tissues express membrane-integrated regulatory proteins that inhibit the activity of autologous complement on cell surfaces. Certain of these complement regulatory proteins act as obligatory cofactors for proteolytic inactivation of activated C4(C4b) by factor I. Extraembryonic tissues and in particular trophoblasts constitute an interface at risk from maternal complement during pregnancy. The present study examined syncytiotrophoblast plasma membrane (STM) cofactor activity for cleavage of immobilized methylamine-treated complement component C4(C4ma), a C4b analog by factor I. Membrane cofactor protein (MCP or CD46) provided most of the cofactor activity in STM preparations. Minor cofactor activity was derived from C4 binding protein that was firmly bound to STM. Cofactor activity for cleavage of C4ma at its two sites for factor I was enhanced at higher concentrations of STM and at lower concentrations cleavage at a C terminal site predominated. Soluble cofactor activity was present in STM preparations and was provided by 65 KDa, 55 KDa and 50 KDa soluble species of MCP that lacked amphiphilic properties. These results are consistent with a major role for MCP in regulation of C4 activity on the maternal-facing surfaces of extraembryonic tissues during human development. Soluble MCP may provide additional fluid phase complement regulatory activity in the maternotrophoblastic zone.

Increase of lymphocytes expressing Fc-receptor class III (CD16) by exposure to human seminal plasma

OBJECTIVE

To characterize conditions for the seminal plasma-induced increase of lymphocytes that express immunoglobulin G-Fc receptor class III (Fc gamma RIII).

DESIGN

Peripheral blood lymphocytes were incubated in diluted seminal plasma or control media. Cells expressing Fc gamma RIII were quantified by using flow cytometry and fluorochrome-labeled monoclonal antibodies specific for Fc gamma RIII. The influence of incubation time, temperature, and seminal plasma concentration was investigated. Physical properties of the active seminal plasma substance were characterized by studying effects of dialysis and ultracentrifugation. The origin of the active seminal plasma substance was investigated by studying activity of autopsy materials from male accessory glands. Identity of cells that are influenced by seminal plasma activity was investigated by using two-color flow cytometry with monoclonal antibodies specific for Fc gamma RIII and different phenotypic markers of leukocytes.

RESULTS

Incubation of lymphocytes in seminal plasma significantly increased percentages of cells expressing Fc gamma RIII. Maximal increases were observed after seminal plasma incubation at 37 degrees C for 90 to 120 minutes and increases were significantly correlated with seminal plasma concentration. Seminal plasma activity was not altered by ultracentrifugation (100,000 x g for 30 minutes) but completely removed by dialysis (12,000 to 14,000 pore size). Fc gamma RIII-positive lymphocytes markedly increased after incubation in prostatic but not in seminal vesicle secretions. Two-color flow cytometry showed that increases of Fc gamma RIII-expressing cells occurred within the subset of CD56-positive natural killer (NK) cells.

CONCLUSIONS

Dialyzable compounds of prostatic origin induce significant increases of NK cells expressing Fc gamma RIII. These findings might reflect a novel regulatory mechanism acting on CD56-positive cells within the female reproductive tract after insemination.

Activity of antiphospholipid antibody ELISA cofactor in different animal sera

A plasma protein cofactor, beta 2-glycoprotein I (beta 2GPI), also known as apolipoprotein H, is necessary to detect certain antiphospholipid antibodies (aPA) to negatively charged phospholipids (PL) in the ELISA. Inasmuch as sera are diluted 1:100 before testing, the concentration of native beta 2GPI may be insufficient to provide an optimal aPA ELISA signal. Therefore, many laboratories add adult bovine serum (ABS) to the diluent buffer to provide a consistent level of cofactor for optimal aPA binding. To determine if other animal sera can provide the cofactor, cat, chicken, dog, horse, goat, guinea pig, mouse, pig, rat, and sheep were tested as diluent supplements in the aPA ELISA. To measure cofactor activity in these animal sera, ELISA for aPA to anionic phospholipids were performed. Two aPA positive patient plasmas were selected for study; one with cofactor-dependent and one with cofactor-independent aPA. Only four of the animal sera tested (bovine, pig, sheep, and cat) supported the cofactor-dependent aPA in ELISA. The cofactor-independent aPA was positive in the presence of each animal serum except bovine and rat. In order to determine whether these animal sera contain a beta 2GPI-like molecule, Western blot analyses were performed. By using a polyclonal antiserum produced to human beta 2GPI, specific beta 2GPI-like cross-reactivity was observed with all animal sera except the chicken. In summary, cofactor activity in animal sera varied significantly; however, bovine and pig sera appear to allow optimal binding of cofactor dependent aPA.

Phenotypic characterization of normal human placental mononuclear cells

The placenta is a rich source of immunocompetent cells. We have studied the phenotype, number and origin of placental mononuclear blood cells isolated from 32 normal term placentae using 4 color flow cytometry. Respective maternal and cord blood leucocyte preparations were also compared. Placental tissue without extraembryonic membranes was cut into small pieces and divided. One portion was washed extensively with ice-cold PBS. Both tissue portions were disrupted in a blender and cells were dissociated by using a 180 mu sieve. Leucocytes were isolated by Ficoll-Hypaque density gradient centrifugation. Maternal and cord bloods were HLA typed and in cases of HLA-A2 or B7/40 disparity, monoclonal anti-HLA antibodies to these antigens showed that unwashed placental tissue contained 35% maternal and 65% fetal cells. This ratio, however, was not reflected for a given cell phenotype. In comparison, washed placental tissue contained cells of fetal origin only. Both unwashed and washed placental tissue contained fewer CD3 and CD4, but more CD8 cells than maternal and cord blood. Markers of NK cells such as, CD16, CD56, and CD57 showed this cellular phenotype to be 15 times more abundant in the placental preparations than in cord and maternal blood. The quantitative differences between peripheral blood and placental CD8 and NK cells were further explored with an antiprogesterone receptor antibody in combination with anti-CD8, anti-CD57 and anti-HLA-DR. The number of progesterone receptor (PGR) positive cells was three times higher in placental tissues than in cord or maternal blood. These data indicate that the phenotypic frequencies of certain placental leucocytes are significantly different from maternal and fetal peripheral blood. Progesterone and the presence of PGR may be important in the differential retention of placental leucocytes.

Predominant expression of the beta subunit of prolyl 4-hydroxylase (disulfide isomerase) in human extravillous trophoblasts

Prolyl 4-hydroxylase is a heterodimeric enzyme that is crucial in the biosynthesis of collagen. The beta subunit of this enzyme is a multifunctional protein which is also known as protein-disulfide isomerase. Immunofluorescence and monoclonal antibody (Mab) 5B5 were used to localize the beta subunit in human extraembryonic tissues. The strongest sites of 5B5 reactivity were extravillous cytotrophoblasts in the basal plate, uteroplacental arteries and amniochorion, syncytiotrophoblast displayed variable weaker reactivity. Only a small fraction of placental 5B5 antigen was detected as a component of prolyl-4-hydroxylase by affinity chromatography on immobilized polyproline. The results indicate a difference in the expression of an endoplasmic reticulum marker between villous and extravillous trophoblast. The predominance of 5B5 antigen in extravillous trophoblast could be associated with an increased ability to synthesize collagen or other enzymatic reactions associated with prolyl 4-hydroxylase beta subunit.

Guinea pig ileitis is attenuated by the leumedin N-(fluorenyl-9- methoxycarbonyl)-leucine (NPC 15199)

Anti-inflammatory properties have been ascribed to a series of N-(fluorenyl-9-methoxycarbonyl) amino acids called leumedins that inhibit the activity of granulocytes and T-lymphocytes. We evaluated one of these leumedins, N-(fluorenyl-9-methoxycarbonyl) leucine (NPC 15199), in a model of ileitis in guinea pigs. Ileitis was induced by intraluminal trinitrobenzenesulfonic acid (TNBS 30 mg/kg in 50% ethanol) in anesthetized guinea pigs. NPC 15199 was administered daily (10 or 100 mg/kg, s.c.). After 7 days, the guinea pigs were anesthetized, and saline was administered intraluminally into an ileal loop created at the site of TNBS administration and was withdrawn after 30 min. The changes in lavage protein, nitrite levels, myeloperoxidase (MPO) activity and mast cell numbers were used as indices of inflammation and injury. NPC 15199 (10 or 100 mg/kg) attenuated or abolished TNBS-induced elevations in lavage protein and nitrite content. Only the high dose of NPC 15199 (100 mg/kg) attenuated ileal MPO activity and mast cell hyperplasia. Histological disturbances induced by TNBS administration included crypt hypertrophy, mucosal and submucosal fibrosis and smooth-muscle hyperplasia. These disturbances were reversed by high-dose NPC 15199 (100 mg/kg) but were minimally affected by low-dose NPC 15199 (10 mg/kg). We conclude that NPC 15199 prevents mucosal injury and dysfunction in this model of intestinal inflammation. Inhibition of granulocyte infiltration does not appear to be essential for the beneficial effects of NPC 15199 and suggests that the alternative actions of NPC 15199 may be pertinent to this model.

Changes in beta 2-glycoprotein I antigenicity induced by phospholipid binding

beta 2-glycoprotein I (beta 2GPI) or apolipoprotein H has been described as a necessary cofactor for antiphospholipid antibody (aPA) binding in ELISA. Some investigators disagree with the beta 2-GPI requirement whereas data from other laboratories indicate that beta 2GPI, not phospholipid (PL), is the antigen for aPA. To investigate the cofactor we have produced three IgG1 monoclonal antibodies (mAb) to human beta 2GPI; 3G9, 1B4 and 3D11. Western blot analyses showed the mAb to bind human beta 2GPI (40 kDa), but no reactivity was observed with adult or fetal bovine sera. In contrast, rabbit anti-beta 2GPI reacted with both human and bovine sera. None of the mAb reacted with phosphatidylserine (PS) or cardiolipin (CL) by ELISA. There were no significant differences in ELISA binding to purified beta 2GPI when the mAb were adjusted to the same concentration. mAb 3G9 and 1B4 gave stronger signals in ELISA after beta 2GPI bound to PS; the increase for 3G9 was significantly greater than for 1B4 (p < 0.002). mAb 3D11 was unique inasmuch as it failed to recognize beta 2PGI bound to PS. In comparison, the rabbit anti-beta 2GPI was unaffected by PS-beta 2GPI binding. These observations indicate that the mAb recognize three distinct epitopes on beta 2GPI. The data suggest that beta 2GPI undergoes conformational changes subsequent to binding PL. Our findings are consistent with the hypothesis that aPA recognize a beta 2GPI neotope formed subsequent to binding PL.

Heparin and pregnancy in women with a history of repeated miscarriages

Many patients who experience recurrent spontaneous abortions (RSA) have high titered antibodies to trophoblast antigens and/or negatively charged phospholipids. Pregnancy success has been documented in some of these patients subsequent to heparin treatment. The effect of heparin on in vitro assays used to detect antibodies to phospholipids and trophoblast antigens has been investigated. We have found that complement-mediated detection of antibodies to trophoblast and lymphocyte antigens is inhibited by absorption of sera with solid-phase heparin. The data show that such inhibition involves an inhibitor and a heparin-sensitive regulator of the inhibitor. Heparin inhibits binding of antiphospholipid antibodies to phospholipids in solid-phase ELISA. The mechanism for this inhibition appears to involve an interaction between heparin and antibody to phospholipid. These findings reveal novel heparin-mediated reactions that bridge immunological and hematological interactions. The extent of heparin modulation of these antibody reactivities should be clarified in future clinical trials involving heparin treatment for RSA.

Nitric oxide release in response to gut injury

We evaluated nitric oxide release in several models of intestinal inflammation through luminal nitrite concentrations. In anesthetized rabbits, piglets, and guinea pigs, luminal lavages were collected from loops of normal or injured small intestine. Lavages were analyzed spectrophotometrically for nitrite (Griess reagent) and protein. Myeloperoxidase (MPO) content of intestinal segments was used as an index of granulocyte infiltration and intestinal inflammation. Acute ileal inflammation was induced by luminal acetic acid + casein in rabbits and luminal deoxycholate in neonatal piglets and adult rabbits. Chronic ileitis was induced in guinea pigs by intraluminal trinitrobenzenesulfonic acid. In each model nitrite levels in ileal lavages were significantly greater than control loops/animals. Increased luminal protein and intestinal MPO activity paralleled the changes in nitrite levels. To determine whether nitric oxide production influenced mucosal repair, segments of ileum were perfused with the L-arginine antagonist NG-nitro-L-arginine methyl ester (L-NAME, 10 mg/ml) after acute acetic acid + casein exposure. L-NAME administration reversed the decline in epithelial permeability characteristic of epithelial restitution, causing an increase in epithelial permeability which was readily reversible. These results suggest that nitrite production is a useful index of gut injury and that nitric oxide may contribute to the functional repair of the epithelial barrier under acute conditions.

Immunological studies of lactoferrin in human placentae

Lactoferrin (LF) and transferrin (Trf) are glycoproteins with strong affinities for ferric ions. Human syncytiotrophoblastic membranes analyzed by enzyme linked immunosorbent assay (ELISA) and immunoblotting were negative with monoclonal and polyclonal antibodies to LF. Immunohistological studies of 35 normal placentae showed that LF was absent from the trophoblast basement membranes, stroma and fetal stem vessel endothelium, but positive cells were occasionally noted in intervillous spaces and fetal stem vessels. In contrast, many LF-positive cells were identified within areas of immunopathology identified by the presence of T cells, HLA-DR-positive macrophages and platelets. Double-antibody experiments showed that the LF-positive cells in these areas reacted with CD15 and CD16 monoclonal antibodies (mAbs), indicating that the cells were polymorphonuclear neutrophils (PMN). PMN from peripheral blood analyzed by flow cytometry and immunocytology also showed reactivities with anti-LF, CD15 and CD16 and we consistently found that circulating PMN reacted better than placental PMN with antibodies to MHC class I antigens and gp 100, (CD67), which is a neutrophil activation marker. PMN adherent within placentae had no detectable MHC class I or CD67 antigens. These findings suggest PMN adherent to placental tissues down-regulate or alter plasma membrane markers. LF appears to play a role in placental inflammation, for LF-positive cells were significantly enriched in areas of immunopathology.

Integrating psychology and obstetrics for medical students: shared labour ward teaching

Two studies relating to the inclusion of psycho-social issues in the training of obstetricians are reported here. The first reports on the extent to which currently practising obstetricians have received training in these aspects. The second explored the value of an innovative teaching approach combining psychological and obstetric training for medical students in the labour ward. A postal survey with responses from 220 obstetricians and paediatricians revealed that little information on psychological aspects of obstetric practice had been included in their undergraduate or postgraduate training or obtained from voluntary continuing education programmes. Experience was the primary source of training in these subjects. The second study explored the impact of joint psychological and obstetric teaching ward rounds for medical students. Students attending these integrated sessions reported being better prepared for the psycho-social aspects of obstetrics and showed a greater awareness of cross-cultural differences in needs of women during birth.

Expression of CD59, a human complement system regulatory protein, in extraembryonic membranes

CD59 (leukocyte cluster of differentiation antigen 59), is a phosphatidylinositol glycan-anchored membrane protein that inhibits lysis of cells by terminal complement system components. To further define complement regulatory proteins relevant to pregnancy, this study characterized the expression of CD59 in human extraembryonic membranes. Immunohistology with CD59 monoclonal antibody MEM-43 showed that this molecule was normally present on the apical surface of the syncytiotrophoblast, on extravillous cytotrophoblast, and amniotic epithelium. Immunoblotting confirmed that first and second trimester syncytiotrophoblast microvilli (STM) contained a glycoprotein similar in mass and glycosylation to CD59 from adult cells and tissues. Reactivities of STM with MEM-43 in ELISA were 2- to 6-fold higher than those of kidney, erythrocyte and platelet membranes. Term placental STM from recurrent spontaneous aborting patients after immunotherapy, reacted with MEM-43 in ELISA similarly to STM from normal individuals. Plasmas from pregnant women and umbilical cords had 50% or greater reactivity with MEM-43 than did normal plasmas. CD59 could help protect extraembryonic epithelia from damage by complement in maternal blood and amniotic fluid. The apical location of CD59 reflects the immunological roles and functional polarization of plasma membranes in the syncytiotrophoblast.

Immune recognition at the maternal-fetal interface: overview

Trophoblast antigens at the maternal-fetal interface that are capable of stimulating maternal immune responses have been studied. Candidates are blood group I and P, HLA, Fc gamma-receptors, TLX, and phospholipids. Antigens I and P on trophoblast have been implicated in pregnancy loss but incompatible i,p mothers are rare. HLA-G is expressed on cytotrophoblast; however, no evidence for HLA-G allotypy or maternal responses to these molecules exists, although HLA-G has been implicated in recruitment of suppressor T cells. Receptors for IgG (Fc gamma-RI, Fc gamma-RII and Fc gamma-III) are present on trophoblast but allotypy is limited to the NA1-NA2 antigen system associated with Fc gamma-RIII on neutrophils. Maternal Fc-gamma R blocking antibodies have been linked to pregnancy success. The TLX alloantigen system was described by using xenogeneic antisera. Idiotype-antiidiotype regulated maternal responses to TLX are proposed as necessary for successful pregnancy. Several putative TLX monoclonal antibodies (Mab) recognize a regulator of complement activation called MCP (membrane cofactor protein, or CD46). Mab to MCP do not exhibit allotypy. Syncytial and cytotrophoblastic membranes are rich sources of MCP. Preliminary data suggest that a conformational site induced by C3b (iC3) binding to MCP may be responsible for TLX allotypy. Certain pregnancy loss patients produce antiphospholipid antibodies (aPA). Some investigators believe that aPA recognize a plasma protein cofactor, beta 2 GPI and not phospholipid per se. We produced three Mab specific for beta 2 GPI, one of which fails to recognize beta 2 GPI bound to phospholipid [corrected].(ABSTRACT TRUNCATED AT 250 WORDS)

South African obstetricians' views on caesarean section

The widespread increase in the rate of caesarean sections performed in the Western world has become a cause for concern. In this country, two systems of health care exist, one provided by the State and the other based on private practice. A high incidence of caesarean sections has been reported, especially among private practitioners. This study investigated doctors' perceptions of caesarean section practices and explored the availability of facilities which could help to reduce the high caesarean section rate. Questionnaires were mailed to all registered obstetricians. Of these 45.2% (233) responded. Findings indicate that private obstetricians are more likely to perform caesarean sections even though they do have good facilities available to monitor or assess difficult deliveries. Other factors influencing their practice are also explored.

AIDS--the Baragwanath experience. Part II. HIV infection in pregnancy and childhood

By the end of 1990, 51 symptomatic children with perinatally acquired HIV infection had been admitted to Baragwanath Hospital. Of 42 children who were followed up for at least 3 months, 15 (35.7%) died and 16 (38.1%) were lost to follow-up. The case fatality rate for these children lies between 35.7% and 73.8%. Most children became symptomatic before the age of 6 months and presenting features seen in over 70% of cases included lymphadenopathy, failure to thrive and hepatomegaly. Surviving children had recurrent admissions to hospital, predominantly for respiratory distress. Many had bacterial pneumonias. Cardiac involvement (cardiomyopathy and cor pulmonale), recurrent serious bacterial infections and neurodevelopmental abnormalities were common. Our experience confirms that vertically acquired HIV infection has a relatively short incubation period and progresses rapidly with cardiorespiratory symptoms predominating. Five HIV seroprevalence studies have been conducted in pregnant women attending Baragwanath Hospital and the Soweto clinics since 1988. The calculated doubling time is between 7 and 21 months. At the end of 1990 the HIV seroprevalence rate in pregnant women was 0.82% (95% confidence limits 0.44-1.19%).

AIDS--the Baragwanath experience. Part IV. Counselling and ethical issues

This fourth part of the series describes the setting up of counselling for HIV-positive patients in response to the need at Baragwanath Hospital. Nurse counsellors were trained and supervised. The work, extending over 2 1/2 years, raised a number of issues for patient care and also for wider community education. Brief reference is made to pertinent ethical and cultural issues.

AIDS--the Baragwanath experience. Part I. Epidemiology of HIV infection at Baragwanath Hospital, 1988-1990

This four-part series describes the experience with HIV infection at Baragwanath Hospital to December 1990. In this first part we give an overview of the emergence of this disease and of its impact on the hospital. From July 1988 to December 1990, 426 HIV-positive individuals were identified: 58 were women identified in surveys at antenatal and gynaecology clinics, 60 were parents of infected babies or sexual contacts of hospitalised patients, and 30 were not inpatients (mainly patients at Soweto clinics). Of the 278 inpatients, 16 were identified in the latter 6 months of 1988, 54 in 1989 and 208 in 1990. Fifty-one per cent of the patients were in the adult medical wards, 11% in surgery, 20% in paediatrics and 18% in other disciplines. One per cent of sera from Wassermann reaction-positive women in mid-1990 were HIV-positive; this also applied to 1% of antenatal women in late 1990 and 2.7% of women with pelvic inflammatory disease. The HIV antigen assay is a useful adjunctive assay in the evaluation of HIV-antibody-positive children. The false/true-positive ratio of a rapid HIV antibody test was 2:1 initially, but the specificity improved with experience. The use of rapid diagnostic assays for HIV must be restricted to laboratories with experience in reading assays and where definitive follow-up testing is assured.

Glycosylation of membrane cofactor protein (CD46) in human trophoblast, kidney and platelets

Many cell surface glycoconjugates are differentiation markers and are involved in cell-cell and intermolecular interactions in development, immunity and cancer. Membrane cofactor protein (MCP) comprises structurally related 65 and 55 kDa glycoproteins that bear O- and N-linked glycans. MCP prevents amplification of autologous complement action on human cells. We used immunoblotting with MCP-specific monoclonal antibody TRA-2-10 to determine lectin-binding properties and glycosidase sensitivities of MCP in a study of cell-specific variation in glycosylation of this protein. The results showed that N-linked glycans on placental syncytiotrophoblast and cytotrophoblast, kidney and platelet MCP are similar in binding to concanavalin A and Lens culinaris lectins, but are not bound by leucophytohemagglutinin. Lectin binding prior to and after neuraminidase digestion indicates that MCP from these sources is highly sialylated. 65 kDa MCP was confirmed to contain more O-linked glycans than 55 kDa MCP. A fraction of platelet 65 kDa MCP is distinct, however, in bearing peripheral fucose residues. Syncytiotrophoblast is unique in containing a 110 kDa form of MCP in non-reducing SDS-PAGE that resembles 65 kDa MCP in glycosylation. Chorion laeve MCP in 4 of 8 preparations was unusually heterogeneous and differed from syncytiotrophoblast MCP after neuraminidase digestion in the forms bound to peanut agglutinin and WGA. The results indicated for the first time, differences in O-linked glycosylation of MCP in chorion laeve cytotrophoblast relative to syncytiotrophoblast, platelet and kidney MCP. We conclude that structures of MCP glycans can differ between trophoblasts and other cell types.

Previous birth outcome of antenatal clinic attenders in northern KwaZulu--perinatal and infant mortality rates

A questionnaire survey was undertaken among pregnant women presenting for the first time to antenatal clinics attached to Mosvold Hospital in rural northern KwaZulu. They were asked details of the outcome of their previous pregnancies and the survival of their last-born children. Of 2,388 mothers interviewed, 1,795 had given birth previously. Of these, 41% had had their last deliveries at home, 47% in hospital and 10% at clinics. The perinatal mortality rate was 38/1,000, with no significant differences between home and hospital or clinic births. The infant mortality rate for live-born children was 62/1,000. Fifty per cent of child deaths occurred at home. The study methodology was easily applied and provided an acceptable alternative technique for measuring child mortality rates, which are so difficult to obtain in rural areas in southern Africa.