Developmental expression of neurokinin A and functional neurokinin-2 receptors in lung.

Peribronchial smooth muscle constriction causes airway stretch, an important mechanical force in developing lung. Little is known about factors influencing these spontaneously active muscle elements. We measured contractile activity of neurokinin (NK) receptors on fetal intrapulmonary smooth muscle by tracheal perfusion assay (n = 11). Injecting either capsaicin or the NK(2) receptor agonist [NLE(10)]NKA resulted in significant (P < 0.05) bronchoconstriction. A specific NK(2) receptor antagonist inhibited constriction caused by endogenous tachykinins released by capsaicin. We then examined NK(2) receptor (n = 44) and NKA (n = 23) ontogeny in human lung. NKA immunostaining was identified in peribronchial nerves in samples with gestational age >12 wk. NK(2) receptor protein was identified in peribronchial and perivascular smooth muscle. These results indicate that endogenous tachykinins released by the developing lung act via NK(2) receptors to cause smooth muscle constriction. We speculate that tachykinins could modulate lung development.

Measurements of maternal protein binding of bupivacaine throughout pregnancy.

UNLABELLED: Pregnancy-related decreases in protein binding may contribute to altered effects of local anesthetics in the parturient. Previous studies have measured protein binding of bupivacaine in term parturients; the current study defines the ratio of bound-to-free bupivacaine throughout gestation at both therapeutic and toxic systemic concentrations of bupivacaine. Venous samples were obtained from 81 women, including 70 parturients, ranging from 7 to 42 wk of gestation and 11 nonpregnant controls. The percent bound bupivacaine at a fixed concentration was determined for each sample at both therapeutic (1 microg/mL) and toxic (5 microg/mL) concentrations using an ultrafiltration technique. Albumin and alpha-1-glycoprotein levels were also measured. Linear regression analysis showed a significant increase in concentration of free bupivacaine throughout gestation at the 5-microg/mL concentration, corresponding to a decrease demonstrated in both albumin and alpha-1-glycoprotein levels. A similar correlation was not found at the 1-microg/mL concentration. Although the relative magnitude of these changes is small, the relative change in free drug throughout gestation is large. Protein binding is only one of several mechanisms that may influence the susceptibility to local anesthetic toxicity in the parturient; however, its relative importance remains unclear. IMPLICATIONS: When venous samples taken from pregnant women were mixed with 5 microg/ml bupivacaine and analyzed, an increase in the free fraction of drug was seen with increasing gestational age, corresponding to decreases in alpha-1-glycoprotein and albumin.

Induction of tenascin-C in cardiac myocytes by mechanical deformation. Role of reactive oxygen species.

Mechanical overload may change cardiac structure through angiotensin II-dependent and angiotensin II-independent mechanisms. We investigated the effects of mechanical strain on the gene expression of tenascin-C, a prominent extracellular molecule in actively remodeling tissues, in neonatal rat cardiac myocytes. Mechanical strain induced tenascin-C mRNA (3.9 +/- 0.5-fold, p < 0.01, n = 13) and tenascin-C protein in an amplitude-dependent manner but did not induce secreted protein acidic and rich in cysteine nor fibronectin. RNase protection assay demonstrated that mechanical strain induced all three alternatively spliced isoforms of tenascin-C. An angiotensin II receptor type 1 antagonist inhibited mechanical induction of brain natriuretic peptide but not tenascin-C. Antioxidants such as N-acetyl-L-cysteine, catalase, and 1, 2-dihydroxy-benzene-3,5-disulfonate significantly inhibited induction of tenascin-C. Truncated tenascin-C promoter-reporter assays using dominant negative mutants of IkappaBalpha and IkappaB kinase beta and electrophoretic mobility shift assays indicated that mechanical strain increases tenascin-C gene transcription by activating nuclear factor-kappaB through reactive oxygen species. Our findings demonstrate that mechanical strain induces tenascin-C in cardiac myocytes through a nuclear factor-kappaB-dependent and angiotensin II-independent mechanism. These data also suggest that reactive oxygen species may participate in mechanically induced left ventricular remodeling.

Apoptosis induced by infection of primary brain cultures with diverse human immunodeficiency virus type 1 isolates: evidence for a role of the envelope.

Apoptosis of neurons and astrocytes is induced by human immunodeficiency type 1 (HIV-1) infection in vitro and has been demonstrated in brain tissue from patients with AIDS. We analyzed a panel of diverse HIV-1 primary isolates for the ability to replicate and induce neuronal and astrocyte apoptosis in primary human brain cultures. Apoptosis was induced three- to eightfold by infection with the blood-derived HIV-1 isolates 89.6, SG3, and ADA. In contrast, the brain-derived HIV-1 isolates YU2, JRFL, DS-br, RC-br, and KJ-br did not induce significant levels of apoptosis. The ability of HIV-1 isolates to induce apoptosis was independent of their replication capacity. Studies of recombinant chimeras between the SG3 and YU2 viruses showed that replacement of the YU2 Env with the SG3 Env was sufficient to confer the ability to induce apoptosis to the YU2 virus. Replacement of the Env V3 regions alone largely conferred the phenotypes of the parental clones. The SG3 Env used CXCR4 and CCR3 as coreceptors for virus entry, whereas YU2 used CCR5 and CCR3. The V3 regions of SG3 and YU2 conferred the ability to use CXCR4 and CCR5, respectively. In contrast, the 3' region of Env, particularly the C3V4 region, was required in conjunction with the V3 region for efficient use of CCR3. These results provide evidence that Env is a major determinant of neurodegenerative mechanisms associated with HIV-1 infection in vitro and raise the possibility that blood-derived viruses which emerge during the late stages of disease may affect disease progression in the central nervous system.

Localization of Bcl-2 in the human fetal müllerian tract.

OBJECTIVE: To determine if apoptosis is involved in development of the human fetal mullerian tract and regression of the uterine septum and to localize Bcl-2. a protein involved with regulating apoptosis. DESIGN: Descriptive controlled study. SETTING: Tertiary academic medical center. PATIENT(S): Eight human fetal uteri from 12 to 21 weeks' gestation. INTERVENTION(S): Immunohistochemistry using a monoclonal antibody for Bcl-2. MAIN OUTCOME MEASURE(S): Immunostaining. RESULTS: Bcl-2 was localized in endometrial cells, tubal muscularis and epithelium, and myometrial edges. It was absent from the septum of 4 uteri. CONCLUSIONS: The presence of Bcl-2 suggests that development of the human fetal müllerian tract involves apoptosis. Bcl-2 may protect the fetal endometrium from apoptosis as it continues to grow. The superior, inferior, and lateral myometrium as well as the tubal epithelium and muscularis also may represent active growth zones that are protected from apoptosis. The notable absence of staining for Bcl-2 in the embryonal uterine septum may indicate lack of protection from apoptosis in this area. This finding supports our hypothesis that apoptosis may be a mechanism by which the uterine septum regresses.

Human ventricular myocytes in vitro exhibit both early and delayed preconditioning responses to simulated ischemia.

Myocardial tissue has been demonstrated to exhibit, in response to brief periods of ischemia, both an immediate period of cytoprotection [i.e. early or "first window" preconditioning response (EPR)], and a later period of cytoprotection [i.e. delayed or "second window" preconditioning response (DPR)], when exposed to a subsequent prolonged hypoxic insult. EPR has been documented in vitro in isolated cardiac myocytes, as well as in situ in intact hearts or trabeculae, for a number of vertebrate species, including humans. However, there are no reports to date of DPR in human cardiac myocytes. To address this question, human ventricular myocytes (HVM) primary isolates were prepared from fetal ventricular muscle, grown to confluency, and studied in primary culture in serum-free medium (> 90%) ventricular myocytes as determined by immunohistochemical analysis with an anti-myosin chain antibody). Using cell viability as determined by trypan blue exclusion, an EPR response could readily be detected following 15, 30, or 60 min of simulated ischemia (SI) in a hypoxic (< 1 tau pO2) buffer containing 11 mmol/l 2-deoxyglucose, followed by a prolonged (c. 17 h) SI challenge. In addition, HVM exposed to 60 min of SI, followed after 24 h by a period of SI, also exhibited a "second window" DPR (80 +/- 10% compared to 71 +/- 11% survival, in preconditioned and non-preconditioned cultures; P < 0.05; n = 18 independent experiments). Thus, in response to short periods of SI, human ventricular myocytes in vitro exhibit both "first window" and "second window" cytoprotective responses to subsequent, prolonged ischemic stress.

Comparison of the ontogeny of protein gene product 9.5, chromogranin A and proliferating cell nuclear antigen in developing human lung.

Pulmonary neuroendocrine cell products, especially bombesin-like peptides, are important modulators of fetal lung growth, morphogenesis and maturation. In the present study, we describe the ontogeny of protein gene product 9.5 (PGP 9.5) in 28 midtrimester human fetal lungs, in comparison to chromogranin A (CGA), a marker of differentiated neuroendocrine cells, and proliferating cell nuclear antigen (PCNA), which is expressed by actively dividing cells. PGP 9.5 immunostaining colocalized with CGA in many cells, although the peak abundance of PGP 9.5 preceded that of CGA by 4 to 6 weeks. In addition, a novel staining pattern was noted for PGP 9.5: diffuse cytoplasmic staining of undifferentiated epithelial cells, which was demonstrated by all of the airways before 15 weeks gestation. After gestational week 15, only the smallest airways demonstrated this pattern. PCNA immunostaining demonstrated age-dependent regional variation. All samples had approximately 25% epithelial cells immunopositive for PCNA. Between 11 and 14 weeks gestation over 50% of the mesenchymal cells were PCNA positive. This mesenchymal staining decreased after 14 weeks, and was rare by week 19. There was no definite correlation between the immunostaining for PGP 9.5 and that for PCNA, although PGP 9.5 positive cells were usually PCNA negative. These observations suggest that other growth factors produced by non-neuroendocrine epithelial cells also participate in lung development.

Levels of urinary beta-core fragment, total oestriol, and the ratio of the two in second-trimester screening for Down syndrome.

Levels of beta-core fragment and total oestriol in second-trimester maternal urine samples were measured in 32 Down syndrome pregnancies and 206 control pregnancies. Beta-core fragment and total oestriol values were corrected for the urinary creatinine level and expressed as multiples of the control medians (MOM). In addition, the ratio of the beta-core fragment level to the total oestriol level, without creatinine correction, was calculated, and expressed as MOM values. The median beta-core fragment, total oestriol, and ratio levels in Down syndrome cases were 5.42, 0.64, and 9.32 MOM, respectively. In the Down syndrome pregnancies, 66 per cent of the beta-core fragment levels were above the 95th centile of control levels, while 22 per cent of the total oestriol levels were below the fifth centile of control levels. In combination with maternal age, measurement of beta-core fragment and total oestriol levels in Down syndrome pregnancy resulted in an 80 per cent detection rate at a 5 per cent false-positive rate. Use of the ratio resulted in a univariate detection rate of 72 per cent. In combination with maternal age, the ratio resulted in a detection rate of 81 per cent at a 5 per cent false-positive rate. Based on this unmatched study, the measurement of a ratio of beta-core fragment to total oestriol levels, without the need for creatinine correction, may be useful in screening for fetal Down syndrome in second-trimester urine.

Immunohistochemical localization of transforming growth factor-alpha, epidermal growth factor (EGF), and EGF receptor in the human fetal ovary.

Peptide growth factors are thought to be involved in adult ovarian regulatory functions. However, little is known about the role of growth factors in human fetal ovarian development. This study is an attempt to identify and localize transforming growth factor-alpha (TGF alpha), epidermal growth factor (EGF), and EGF receptor (EGF-R) in human fetal ovaries. Ovaries were obtained from first and second trimester elective abortuses. Immunohistochemistry was performed on paraffin sections of these specimens after fixation. We examined the sections microscopically using the specific antibodies against TGF alpha, EGF, and EGF-R. Phosphate-buffered saline and preimmune IgG were used as negative controls. First and second trimester ovaries stained positively for all three proteins. Staining was significantly more intense in the oocytes than in the stroma. Negative controls did not stain. These results combined with our previous demonstration of messenger ribonucleic acid for these growth factors suggest roles for TGF alpha, EGF, and EGF-R in human fetal ovarian development. The strong staining in the oocytes suggests a possible autocrine or paracrine role of these growth factors in human oocyte growth in utero.

HIV-1 Langerhans' cell tropism associated with heterosexual transmission of HIV.

Heterosexual transmission by vaginal intercourse accounts for most transmission of human immunodeficiency virus-type 1 (HIV-1) in Africa and Asia but is less important in the HIV-1 epidemics of the United States and Western Europe. Epithelial Langerhans' cells (LCs) represent a possible source of initial cell contact for vaginal infection. Fifteen primary isolates of HIV-1 from U.S. homosexuals and 18 HIV-1 isolates from Thailand heterosexuals were evaluated for growth in LCs of U.S. origin. All the viruses from the Thai heterosexuals, which were subtype E, grew more efficiently in the LCs than any of the viruses from the U.S. homosexuals, which are subtype B. These results suggest that LC tropism is associated with the efficiency of heterosexual transmission of HIV.

Second-trimester levels of maternal urinary gonadotropin peptide in Down syndrome pregnancy.

Urinary gonadotropin peptide (UGP; beta-core fragment), a major metabolite of human chorionic gonadotropin (hCG), was shown recently to be markedly elevated in Down syndrome pregnancy between 19 and 22 weeks of gestation. To confirm and extend this finding, we obtained maternal urine and matching maternal serum samples from 14 cases of Down syndrome and six other aneuploidies between 17 and 21 weeks of gestation. UGP was measured in all these samples and in 91 singleton control urines. Results were corrected for urinary creatinine level and expressed as multiples of the control median (MOM). hCG levels were assayed in all serum samples from the cases and compared with previously established reference values. The median UGP level in Down syndrome cases was 5.34 MOM (range 2.71-12.57); 88 per cent of the values were above the 95th centile of control levels after modelling. The median maternal serum hCG level for the same cases was 2.20 MOM (range 0.84-3.40); 36 per cent of the values were above the 95th centile. The level of UGP in every case including all other aneuploidies was higher than the comparable maternal serum hCG level. Elevated UGP measurements are strongly associated with fetal Down syndrome during the second trimester and could contribute to improved Down syndrome screening protocols that are more accessible and less expensive than are currently available.

Oligodendroglial development in human fetal cerebrum.

We have successfully established mixed glial cell primary cultures prepared from individual fetal human brains (15-18 weeks' gestation in age). Cultures were maintained for as long as 3 months in either 10% fetal calf serum (FCS) or serum-free chemically defined medium (CDM). By morphological and immunohistochemical criteria, the precursor cell for human oligodendrocytes (O-2A cell) was identified. This cell exhibited the bipolar morphology and A2B5-positive (A2B5+) immunoreactivity typical of the O-2A precursor cell. With time in culture, cells possessing a stellate morphology appeared, some of which stained with the O4 antibody, indicative of cell differentiation in the oligodendroglial lineage. At yet older culture age, arborized cells bearing the O1 (galactocerebroside, GC) immunohistochemical marker and displaying the morphological characteristics typical of more mature oligodendrocytes were found, confirming their oligodendroglial identity. Oligodendroglial differentiation was supported best by CDM rather than FCS. To complement these observations, double immunofluorescent studies were performed on parietal sections from human fetal brains at 20 to 22 weeks of gestation. Bipolar A2B5+, multipolar A2B5+/O4+, and arborized A2B5-/O1+ cells were found, thus confirming the presence of oligodendrocytes in human fetal brain at this stage of prenatal development and consistent with the observations made in cell culture.

Symmetrical terminal transverse limb defects: report of a twenty-week fetus.

A 20-week gestation hydropic Thai fetus is reported who had symmetrical absence of each hand and forefoot with persistence of digit-like nubbins on each limb. The histologic studies showed there was calcified acellular material in the digit-like nubbins, consistent with infarcted blood vessels, and cartilaginous structures that represented possibly the distal metacarpal articulating surface. The red blood cell indices of both parents were consistent with their being heterozygous for a hemoglobinopathy, such as alpha-thalassemia, which is common in Thais. The infarcted blood vessels could be the result of thrombosis of the digital arteries in the fetus due to a hemoglobinopathy such as hemoglobin Bart's, just as rabbit fetuses homozygous for brachydactyly have transverse terminal digit amputations following digital vessel occlusions due to macrocytic anemia. This was the only child with symmetrical absence of the hands and feet identified among 123,489 liveborn and stillborn infants surveyed for major malformations.

Human fetal uterine cells: culture, characterization, and analysis of growth factor receptor gene expression.

Peptide growth factors are postulated to have a role in uterine maturation during organogenesis. The purpose of this investigation was to establish a model to study human fetal uterine development. To that end, we describe an in vitro culture system and have characterized the cell types present during the period of uterine maturation. In addition, we evaluated the pattern of growth factor receptor gene expression in these cultured cells. Uteri were dissected from human first and second trimester fetuses (n = 20). Characterization studies were performed against three intermediate filament proteins, cytokeratin, vimentin, and desmin, and against a fibroblast-associated cell surface antigen. Ribonucleic acid was extracted from pure stroma-like cultures, and reverse transcription-polymerase chain reaction (RT-PCR) was used to amplify sequences specific for the epidermal growth factor receptor (EGF-R), fibroblast growth factor receptor (FGF-R), and the insulin receptor (I-R). Two predominant cell types were identified in the cultured fetal tissue: stroma-like cells and clusters of uterine epithelium. Immunofluorescent studies demonstrated positive expression of cytokeratin, vimentin, and a fibroblast-associated antigen in the fetal stroma-like cells, in contrast to adult stromal cells, which consistently expressed only vimentin. Using RT-PCR, the uterine cells were positive for the EGF-R, two forms of the FGF-R, and two forms of the I-R. In conclusion, we provide the first report of a human fetal cell culture system. Characterization studies of fetal stroma-like cells demonstrate immunoreactivity to vimentin, cytokeratin, and a fibroblast antigen, in contrast to the adult stromal cell, which consistently expressed only vimentin. Using RT-PCR, we found that messenger ribonucleic acids for the EGF-R and two forms of both the FGF-R and I-R are expressed. This model may be useful for studying the dynamics of human uterine development in vitro.

Cervical ectopic pregnancy: results of conservative treatment.

PURPOSE: To review experience with early sonographic diagnosis and fertility-preserving treatment of cervical ectopic pregnancy. MATERIALS AND METHODS: The authors evaluated 12 consecutive cases of cervical ectopic pregnancy diagnosed with ultrasound (US) and treated with methods that successfully preserved the uterus. Gestational age, sonographic findings, means of conception, and method of treatment were recorded. RESULTS: Gestational age at diagnosis ranged from 5.0 to 7.9 weeks. Cardiac activity was documented in nine cases. Patients were treated as follows: transvaginal US-guided injection of potassium chloride into the embryo or gestational sac (n = 6), uterine artery embolization followed by dilation and evacuation (n = 4), dilation and evacuation after ligation of uterine artery branches (n = 1), and uterine artery embolization followed by administration of systemic methotrexate (n = 1). The cervical pregnancy was successfully ablated with one treatment in all cases. No patient required hysterectomy, and only one patient required transfusion. Two patients subsequently delivered healthy babies; three other patients have been able to conceive successfully. CONCLUSION: When cervical ectopic pregnancy is diagnosed early, US-guided termination or other conservative procedures allow preservation of the uterus, thus maintaining potential fertility.

Combination oral contraceptives.

PIP: Oral contraceptives (OC) are the most popular and reliable method of reversible contraception in the US. Their safety record has been studied and improved over the course of three decades of use. Deaths from OC-induced thromboembolism were related to doses higher than 80 mcg of synthetic estrogen in each pill. OC formulation has therefore been changed repeatedly over the years to reduce the estrogenic content to 50 mcg or less in an effort to eliminate this serious adverse effect. Currently, most practitioners prescribe OC with 35 mcg or less of ethinyl estradiol. With the low-dose pill, typical protection for users from unwanted pregnancy remains more than 95% effective. The author gives his OC use recommendations for first-time users; women with sedentary lifestyles; women who previously used a brand-name OC without any serious side effect; women with premenstrual symptoms; postpartum, postoperative, and postabortal patients; women of perimenopausal age; women with signs of hyperandrogenism or idiopathic hirsutism; and patients receiving long-term concurrent therapy with other drugs. He also discusses the use of OC as emergency/postcoital contraception and for noncontraceptive purposes.^ieng

Localization and timing of appearance of insulin, insulin-like growth factor-I, and their receptors in the human fetal müllerian tract.

OBJECTIVE: The factors that regulate fetal müllerian tract development are still unknown. Insulin and insulin-like growth factor-I are peptides postulated to serve as autocrine or paracrine regulators of cell activity. We have previously demonstrated that messenger ribonucleic acid for insulin and insulin-like growth factor-I receptors are expressed in fetal uterine tissues. We undertook this study to determine by immunohistochemical techniques the exact location of these two growth factors and their receptors in the human fetal uterus. STUDY DESIGN: We obtained freshly discarded human fetal uteri (n = 12) between 15 and 22 weeks of gestation from elective pregnancy terminations. Frozen-section specimens were incubated with antibodies against insulin, insulin-like growth factor-I, insulin receptor, and insulin-like growth factor-I receptor. These sections were then incubated with a second antibody conjugated to fluorescein isothiocyanate and examined under phase and fluorescent microscopy. RESULTS: The fetal endometrium at 19 and 22 weeks of gestation contained insulin, insulin-like growth factor-I, insulin receptor, and insulin-like growth factor-I receptor. The distribution of immunofluorescence in the endometrium is similar for both insulin and its receptor. The same pattern of immunostaining was likewise demonstrated for insulin-like growth factor-I and its receptor. CONCLUSION: The localization of these growth factors and their receptors, combined with our previous messenger ribonucleic acid data, suggest an autocrine or paracrine role for insulin and insulin-like growth factor-I in the developing human fetal müllerian tract.

Expression of messenger ribonucleic acids encoding for basic fibroblast growth factor (FGF) and alternatively spliced FGF receptor in human fetal ovary and uterus.

Basic fibroblast growth factor (bFGF) is an angiogenic and mitogenic peptide that may have modulatory effects in the adult ovary and uterus. The FGF receptor is a tyrosine kinase and has similar affinity for both acidic FGF and bFGF. The ligand-binding portion of the receptor has three immunoglobulin-like domains. bFGF and the FGF receptor have been localized in the fetal rat ovary and Mullerian duct. bFGF is a proliferative agent recently shown to be vital for long term cultures of mouse fetal primordial germ cells. Expression of bFGF and FGF receptor mRNA have not heretofore been reported in human fetal ovary and uterus. We prepared RNA from whole human fetal ovaries and uteri at 10, 15, 19, and 22 weeks gestation. After reverse transcription of the RNA into cDNA, we used polymerase chain reaction (PCR) primers directed to specific portions of bFGF and the FGF receptor and performed PCR amplification using the fetal cDNA. We found mRNA expression of bFGF and two forms of FGF receptor in all fetal ovaries and uteri at these developmental stages. One of the PCR products for the FGF receptor was the sequence that contained three immunoglobulin-like domains, whereas a second PCR-amplified fragment was consistent with a FGF receptor mRNA that has a 267-basepair deletion in the first immunoglobulin-like loop. We conclude that bFGF and two forms of the FGF receptor mRNA are expressed in human fetal ovary and uterus. The finding that both bFGF and the FGF receptor are concurrently expressed suggests that bFGF may serve as an autocrine or paracrine modulator during early development of the human reproductive tract.

Phenotypic characteristics of lymphocyte populations isolated from middle gestation human placenta.

In order to characterize the phenotypic composition of populations of lymphoid cells in maternal and fetal tissues during the period of middle gestation, mononuclear cells were isolated from maternal peripheral blood, fetal spleen, fetal thymus and placenta of 18-24 week pregnancies. Peripheral blood and placental isolates were stained for a number of lymphoid cell markers by indirect immunofluorescence and analyzed by flow cytometry. Studies were performed on both freshly isolated mononuclear cell preparations and in vitro cultured cells after selective expansion in interleukin 2 (IL2). Fresh placental mononuclear cell isolates were an average 20% CD3+; their CD4/CD8 ratios varied among individuals. An average of 68% of the lymphocytes isolated from maternal peripheral blood were CD3+. Placental and maternal peripheral blood isolates had comparable percentages of CD16+ and CD20+ cells, while CD56+ cells were present at significantly greater numbers in the lymphocyte compartment of placenta (17%) than in peripheral blood (3%; P < 0.01). Lymphocyte isolates were expanded by culture with IL2 and PHA and stained to determine if propagated lymphocyte populations are representative of initial isolates. Expansion of all lymphocyte isolates favored CD3 phenotypes and CD8 phenotypes. Compared to expanded placenta-derived populations, expanded peripheral blood lymphocytes were similar with regard to percentages of all phenotypes except gamma/delta T cells which represented more of placental lymphocytes (10%) than peripheral lymphocytes (5%; P < 0.01). Surface HLA typing determined propagated placenta-derived lymphocytes to be of maternal and not fetal origin. In vitro propagation of placental mononuclear cell isolates may therefore provide populations of maternal CD3+ lymphocytes for assessment of function and specificity.