Fetal foot length--a new parameter for assessment of gestational age

Estimated Gestational Age From Infant's Foot Length in Japanese

Aim In developed countries including Japan, gestational age (GA) is predicted by the last menstrual period (LMP) and/or fetal ultrasound. In some developing countries, GA is predicted by infant's foot length (FL). Pregnant women who did not have pregnancy check-up is not infrequent in Japan, therefore there are sometimes opportunities to estimate the GA from infants after the delivery. The aim of this study is to determine the estimated GA formula from infant's FL in Japanese. Methods This study was a prospective cohort study. Infants between May 2021 and August 2021 at Iizuka Hospital and Tagawa Hospital or transferred from other hospitals within 24 hours of birth were collected. GA was determined using LMP and/or fetal ultrasound. The infant's FL was measured with a digital caliper within 24 hours of birth. The relationship between FL and GA was analyzed by simple regression analysis to determine the coefficient of determination (R²). The infant's FL of males and females, infant's FL of preterm and term, and infant's FL of low birth weight and appropriate weight infants were performed by the t-test as independent samples. A statistically significant difference was p < 0.05. Statistical analysis was performed using JMP Pro 16 (SAS Institute Japan Co., Ltd., Minato-ku, Tokyo). Results Ninety of the 135 infants were enrolled. The average GA was 38.2 ± 1.8 weeks, the average infant's FL was 7.230 ± 0.411 centimeter (cm), and the range of the infant's FL was 5.385 to 8.089 cm. The estimated GA formula, GA = 18.49 + 0.27 x infant's FL (R² = 0.39), was determined. Conclusions We determined the estimated GA formula from the infant's FL. There are some limitations and care should be taken in the use.

Relationship Between Foot Length and Gestational Age in Pakistan

Preterm births have a high risk of mortality. Therefore, knowledge of the gestational age (GA) at birth is crucial to guide the appropriate management of a newborn. Common methods for estimating GA such as the last menstrual period, ultrasonography, and post-natal Ballard scoring have some limitations. This study aimed to determine the relationship between foot length and GA to develop and validate an equation for predicting GA of Pakistani newborns. We conducted a prospective study in a large obstetric hospital in Pakistan. Data for this analysis were extracted from the hospital files of eligible women by trained study midwives. Midwives were also trained in performing the Ballard examination and taking foot length using a disposable measuring tape within an hour of the birth. The GA was calculated using an android-based GA calculator. Simple and multiple linear regression were used to construct predicting equations for GA. Both the foot length and GA were available for 1542 cases. The median GA was 34.5 (IQR 4.7) weeks and the median foot length was 7 cm (IQR 1.4). There was a positive linear relationship between foot length and GA (r² 81.7%, P-value < .001). Stratified analysis showed an r² of 81.7% for males and 81.6% for females. The r² for stillbirths was 84.1% and, 82.3% for live births. The r² for macerated stillbirths was 88.6% and 90.6% for fresh stillbirths. In resource poor settings, the use of foot length can estimate GA in both live births and stillbirths and can easily identify preterm infants.

Could perturbed fetal development of the ovary contribute to the development of polycystic ovary syndrome in later life?

Polycystic ovary syndrome (PCOS) affects around 10% of young women, with adverse consequences on fertility and cardiometabolic outcomes. PCOS appears to result from a genetic predisposition interacting with developmental events during fetal or perinatal life. We hypothesised that PCOS candidate genes might be expressed in the fetal ovary when the stroma develops; mechanistically linking the genetics, fetal origins and adult ovarian phenotype of PCOS. In bovine fetal ovaries (n = 37) of 18 PCOS candidate genes only SUMO1P1 was not expressed. Three patterns of expression were observed: early gestation (FBN3, GATA4, HMGA2, TOX3, DENND1A, LHCGR and FSHB), late gestation (INSR, FSHR, and LHCGR) and throughout gestation (THADA, ERBB4, RAD50, C8H9orf3, YAP1, RAB5B, SUOX and KRR1). A splice variant of FSHB exon 3 was also detected early in the bovine ovaries, but exon 2 was not detected. Three other genes, likely to be related to the PCOS aetiology (AMH, AR and TGFB1I1), were also expressed late in gestation. Significantly within each of the three gene groups, the mRNA levels of many genes were highly correlated with each other, despite, in some instances, being expressed in different cell types. TGFβ is a well-known stimulator of stromal cell replication and collagen synthesis and TGFβ treatment of cultured fetal ovarian stromal cells inhibited the expression of INSR, AR, C8H9orf3 and RAD50 and stimulated the expression of TGFB1I1. In human ovaries (n = 15, < 150 days gestation) many of the same genes as in bovine (FBN3, GATA4, HMGA2, FSHR, DENND1A and LHCGR but not TOX3 or FSHB) were expressed and correlated with each other. With so many relationships between PCOS candidate genes during development of the fetal ovary, including TGFβ and androgen signalling, we suggest that future studies should determine if perturbations of these genes in the fetal ovary can lead to PCOS in later life.

Macroscopic whole-mounts of the developing human fetal urogenital-genital tract: Indifferent stage to male and female differentiation

We present a detailed review of fetal development of the male and female human urogenital tract from 8 to 22 weeks gestation at the macroscopic and morphometric levels. Human fetal specimens were sexed based on macroscopic identification of fetal testes or ovaries, Wolffian or Müllerian structures and the presence of the SRY gene in the specimens at or near the indifferent stage (8-9 weeks). Specimens were photographed using a dissecting microscope with transmitted and reflected light. Morphometric measurements were taken of each urogenital organ. During this time period, development of the male and female urogenital tracts proceeded from the indifferent stage to differentiated organs. The kidneys, ureters, and bladder developed identically, irrespective of sex with the same physical dimensions and morphologic appearance. The penis, prostate and testis developed in males and the clitoris, uterus and ovary in females. Androgen-dependent growth certainly influenced size and morphology of the penile urethra and prostate, however, androgen-independent growth also accounted for substantial growth in the fetal urogenital tract including the clitoris.

Development of the human penis and clitoris

The human penis and clitoris develop from the ambisexual genital tubercle. To compare and contrast the development of human penis and clitoris, we used macroscopic photography, optical projection tomography, light sheet microscopy, scanning electron microscopy, histology and immunohistochemistry. The human genital tubercle differentiates into a penis under the influence of androgens forming a tubular urethra that develops by canalization of the urethral plate to form a wide diamond-shaped urethral groove (opening zipper) whose edges (urethral folds) fuse in the midline (closing zipper). In contrast, in females, without the influence of androgens, the vestibular plate (homologue of the urethral plate) undergoes canalization to form a wide vestibular groove whose edges (vestibular folds) remain unfused, ultimately forming the labia minora defining the vaginal vestibule. The neurovascular anatomy is similar in both the developing human penis and clitoris and is the key to successful surgical reconstructions.

Contrasting mechanisms of penile urethral formation in mouse and human

This paper addresses the developmental mechanisms of formation of the mouse and human penile urethra and the possibility that two disparate mechanisms are at play. It has been suggested that the entire penile urethra of the mouse forms via direct canalization of the endodermal urethral plate. While this mechanism surely accounts for development of the proximal portion of the mouse penile urethra, we suggest that the distal portion of the mouse penile urethra forms via a series of epithelial fusion events. Through review of the recent literature in combination with new data, it is unlikely that the entire mouse urethra is formed from the endodermal urethral plate due in part to the fact that from E14 onward the urethral plate is not present in the distal aspect of the genital tubercle. Formation of the distal portion of the mouse urethra receives substantial contribution from the preputial swellings that form the preputial-urethral groove and subsequently the preputial-urethral canal, the later of which is subdivided by a fusion event to form the distal portion of the mouse penile urethra. Examination of human penile development also reveals comparable dual morphogenetic mechanisms. However, in the case of human, direct canalization of the urethral plate occurs in the glans, while fusion events are involved in formation of the urethra within the penile shaft, a pattern exactly opposite to that of the mouse. The highest incidence of hypospadias in humans occurs at the junction of these two different developmental mechanisms. The relevance of the mouse as a model of human hypospadias is discussed.

New insights into human female reproductive tract development

We present a detailed review of the embryonic and fetal development of the human female reproductive tract utilizing specimens from the 5th through the 22nd gestational week. Hematoxylin and eosin (H&E) as well as immunohistochemical stains were used to study the development of the human uterine tube, endometrium, myometrium, uterine cervix and vagina. Our study revisits and updates the classical reports of Koff (1933) and Bulmer (1957) and presents new data on development of human vaginal epithelium. Koff proposed that the upper 4/5ths of the vagina is derived from Müllerian epithelium and the lower 1/5th derived from urogenital sinus epithelium, while Bulmer proposed that vaginal epithelium derives solely from urogenital sinus epithelium. These conclusions were based entirely upon H&E stained sections. A central player in human vaginal epithelial development is the solid vaginal plate, which arises from the uterovaginal canal (fused Müllerian ducts) cranially and squamous epithelium of urogenital sinus caudally. Since Müllerian and urogenital sinus epithelium cannot be unequivocally identified in H&E stained sections, we used immunostaining for PAX2 (reactive with Müllerian epithelium) and FOXA1 (reactive with urogenital sinus epithelium). By this technique, the PAX2/FOXA1 boundary was located at the extreme caudal aspect of the vaginal plate at 12 weeks. During the ensuing weeks, the PAX2/FOXA1 boundary progressively extended cranially such that by 21 weeks the entire vaginal epithelium was FOXA1-reactive and PAX2-negative. This observation supports Bulmer's proposal that human vaginal epithelium derives solely from urogenital sinus epithelium. Clearly, the development of the human vagina is far more complex than previously envisioned and appears to be distinctly different in many respects from mouse vaginal development.

Postnatal Foot Length to Determine Gestational Age: A Pilot Study

Gestational age is a critical factor in the management, decision-making, prognostication and follow-up of newborn infants. It is also essential for research and epidemiology. In the absence of an early assessment of fetal gestation by abdominal ultrasound, many neonatal units in developing countries determine gestational age by neonatal scores and last menstrual period-both of which are highly inaccurate. The aim of this pilot study was to determine whether postnatal foot length measurement could accurately determine gestational age in a specified South African hospitalized neonatal population. Foot length was measured with a plastic Verniere's caliper. Foot length was shown to correlate well with gestational age (r = 0.919,p < 0.001). Intra-observer and inter-observer variability of foot length measurements was low. Foot length can therefore be used with high accuracy to determine the gestational age in a population where there is poor access to or utilization of antenatal sonar.

Hexabromocyclododecane concentrations in Canadian human fetal liver and placental tissues

Detectable concentrations of the flame retardant hexabromocyclododecane (HBCD) have been reported in human tissues worldwide, but investigations to determine fetal exposure to this brominated flame retardant are lacking. This study was undertaken to determine the concentrations of α-, β- and γ-HBCD in human tissues (fetal liver and placenta) from Canada. Tissue samples were collected over a thirteen year period following elective pregnancy terminations in Montreal, Quebec, Canada. Samples were extracted using homogenisation with solvent, cleaned up using adsorption chromatography and analysis was performed with liquid chromatography-tandem mass spectrometry. Total HBCD concentrations ranged from below the limit of detection (<LOD; <1 ng g(-1)) to 4500 ng g(-1) lipid in fetal livers and <LOD (<1 ng g(-1)) to 5600 ng g(-1) lipid in placental tissue. No clear temporal trend was established in liver samples, nor was a significant relationship observed between fetal age and ΣHBCD concentrations. Temporal differences, however, were noted in placental tissues before and after 2005. HBCD concentrations in liver:placental paired tissue samples did not show a correlation. HBCD was found in placental tissues from Canadian women and results indicate that HBCD was present, at measurable concentrations, in developing fetuses from as early as 6.5 weeks.

VEGF 165 b in the developing vasculatures of the fetal human eye

VEGF(165) b is an anti-angiogenic form of VEGF(165) produced by alternative splicing. The localization of pro-angiogenic VEGF(165) and anti-angiogenic VEGF(165) b was investigated during development of the vasculatures in fetal human eyes from 7 to 21 weeks gestation (WG). The fetal vasculature of vitreous, which includes tunica vasculosa lentis (TVL), had moderate VEGF(165) immunoreactivity at 7WG and very little VEGF(165) b. Both forms were elevated at 12WG. VEGF(165) then decreased around 17WG when the TVL regresses but VEGF(165) b remained elevated. In choroid, VEGF(165) was present in forming choriocapillaris (CC) and retinal pigment epithelium (RPE) at 7WG while VEGF165b was present in CC and mesenchymal precursors within the choroidal stroma. By 21WG, both forms were elevated in RPE and choroidal blood vessels but VEGF(165) b was apical and VEGF(165) basal in RPE. Diffuse VEGF(165) immunoreactivity was prominent in 12WG innermost retina where blood vessels will form while VEGF(165) b was present in most CXCR4(+) progenitors in the inner neuroblastic layer and migrating angioblasts in the putative nerve fiber layer. By 21WG, VEGF(165) was present in nerve fibers and VEGF(165) b in the inner Muller cell process. The localization of VEGF(165) b was distinctly different from VEGF(165) both spatially and temporally and it was often associated with nucleus in progenitors.

Development of fetal intestinal length during 2nd-trimester in normal and pathologic pregnancies

Linear growth of the human fetal gastrointestinal tract is not often discussed in the literature, and little is known about the effects of chromosomal abnormalities and intrauterine growth restriction (IUGR) on intestinal length, especially during the 2nd trimester. Accurate evaluation of intestinal length and knowledge of normal and reference values are of clinical importance. For example, intestinal resection may be necessary in preterm infants with necrotizing enterocolitis or mid-gut volvulus, and the surgeon should use data to be judicious in the amount removed. Linear measurements are essential in evaluating fetal development ultrasonographically and are an integral part of the postmortem examination. The intestinal lengths of 203 2nd-trimester fetuses and premature infants were measured. Small intestine length (SIL), colon length (CL), total bowel length (TBL; TBL  =  SIL + CL), and the length of the appendix (AL) increased with gestational age. No differences between the genders were observed. Colon length increased secondary to maceration, but no such effects were shown on SIL, TBL, or AL. No differences were shown in relation to IUGR. Small intestine length, CL, and TBL, but not AL, were shorter in fetuses with trisomy 21. Appendix length was not affected by any of the studied factors. We propose that the measurement of the length of the appendix may be used as an additional parameter for the postmortem evaluation of gestational age. Furthermore, its assessment may have potential as an ultrasonographic indicator of gestational age, particularly for the 2nd trimester.

Age determination enhanced by embryonic foot bud and foot plate measurements in relation to Carnegie stages, and the influence of maternal cigarette smoking

BACKGROUND

Reliable age determination of first-trimester human embryos and fetuses is an important parameter for clinical use and basic science. Age determination by ultrasound or morphometric parameters of embryos 4-6 weeks post conception (p.c.) have been questioned, and more accurate methods are required. Data on whether and how maternal smoking and alcohol consumption influence embryonic and fetal foot growth is also lacking.

METHODS

Embryonic tissue from 102 first-trimester legal abortions (aged 35-69 days p.c.) were collected. All women answered a questionnaire concerning smoking and drinking habits, and delivered a urine sample for cotinine analysis. Embryonic age was evaluated by vaginal ultrasound measurements and by post-termination foot length and compared with the Carnegie stages.

RESULTS

Foot bud and foot plate were defined and measured as foot length in embryos aged 35-47 days p.c. (range 0.8-2.1 mm). In embryos and fetuses aged 41-69 days p.c., heel-toe length was measured (range 2.5-7.5 mm). We found a significant linear correlation between foot length and age. Morphology of the feet was compared visually with the Carnegie collection, and we found that the mean ages of the two collections correlated well. Foot length was independent of gender, Environmental Tobacco Smoke, maternal smoking and alcohol consumption.

CONCLUSION

Foot length correlated linearly to embryonic and foetal age, and was unaffected by gender, ETS, maternal smoking and alcohol consumption.

Maturation of the fetal human choriocapillaris

PURPOSE

The purpose of this study was to examine the structural and functional maturation of the choriocapillaris (CC) and to determine when fenestrations form, the capillaries are invested with pericytes, and the endothelial cells (ECs) became functional.

METHODS

Immunohistochemistry was performed on cryopreserved sections of embryonic/fetal human eyes from 7 to 22 weeks' gestation (WG), using antibodies against PAL-E, PV-1 (fenestrations), carbonic anhydrase IV (CA IV), eNOS, and alpha-smooth muscle actin (alphaSMA) and NG2 (two pericyte markers) and the EC marker (CD31). Alkaline phosphatase (APase) enzymatic activity was demonstrated by enzyme histochemistry. Transmission electron microscopy (TEM) was performed on eyes at 11, 14, 16, and 22 WG. Adult human eyes were used as the positive control.

RESULTS

All EC markers were present in the CC by 7 WG. PAL-E, CA IV, and eNOS immunoreactivities and APase activity were present in the CC by 7 to 9 WG. TEM analysis demonstrated how structurally immature this vasculature was, even at 11 WG: no basement membrane, absence of pericytes, and poorly formed lumens that were filled with filopodia. The few fenestrations that were observed were often present within the luminal space in the filopodia. Contiguous fenestrations and significant PV-1 were not observed until 21 to 22 WG. alphaSMA was prominent at 22 WG, and the maturation of pericytes was confirmed by TEM.

CONCLUSIONS

It appears that ECs and their precursors express enzymes present in adult CC well before they are structurally mature. Although ECs make tight junctions early in development, contiguous fenestrations and mature pericytes occur much later in development.

Vascular precursors in developing human retina

PURPOSE

Prior investigation has demonstrated that angioblasts are present in the inner retinas of human embryos and fetuses and that they differentiate and organize to form the primordial retinal vasculature. The purpose of this study was to characterize these angioblasts further and examine ligands that might control their migration and differentiation.

METHODS

Immunohistochemistry was used to localize stroma-derived factor-1 (SDF-1), its receptor CXCR4, stem cell factor (SCF), and its receptor c-Kit on sections obtained from human eyes at from 6 to 23 weeks' gestation (WG). Coexpression of CD39 (marker for retinal angioblasts and endothelial cells) and CXCR4 or c-Kit was investigated by confocal microscopy.

RESULTS

SDF-1 was prominent in inner retina with the greatest reaction product near the internal limiting membrane (ILM). SCF immunoreactivity was also confined to the inner retina and increased significantly between 7 and 12 WG. The level of both ligands declined by 22 WG. A layer of CXCR4(+) and c-Kit(+) precursors, some of which coexpressed CD39, existed in the inner retina from 7 to 12 WG. With migration, c-Kit was downregulated, whereas CD39(+) cells continued to express CXCR4 as they formed cords. With canalization, CXCR4 expression was downregulated.

CONCLUSIONS

Embryonic human retina has a pool of precursors (CXCR4(+) and c-Kit(+)) that enlarged centrifugally during fetal development. From this pool emerges angioblasts, which migrate anteriorly into the nerve fiber layer where SDF-1 and SCF levels are highest. c-Kit expression declines with apparent migration, and CXCR4 expression declines with canalization of new vessels. Both SCF and SDF-1 are associated with the differentiation of retinal precursors into angioblasts and their migration to sites of vessel assembly.

The initial fetal human retinal vasculature develops by vasculogenesis

There is increasing evidence that the hemangioblast, a common progenitor for hematopoietic cells and endothelial cells, participates in embryonic and extra-embryonic vasculogenesis in some organs. Whether resident angioblasts or endothelial progenitor cells (EPCs) contribute to human retinal vasculogenesis is still a matter of controversy. To address this controversy, fetal human retinas of 6-23 weeks gestation (WG) were examined using immunohistochemistry and a panel of antibodies against endothelial cell markers (CD34, CD31), a marker for retinal angioblasts and endothelium (CD39/ecto-ADPase), and a marker for precursors and hemangioblasts (CXCR4). Confocal microscopic spectral analysis and double labeling with Ki67 was used to identify the proliferating cell types. In the inner neuroblastic layer of the 6-8 WG retina and in the putative ganglion cell layer in avascular regions of older eyes (14 WG-20 WG), scattered CD39+ angioblasts were well in advance of forming vasculature. There was a layer of CXCR4+ cells in the inner retina that was reduced in size with development. As blood vessels formed, CD39+ cells were always well in advance of the vascular front and they expressed CXCR4. This demonstrates that a pool of resident angioblasts express CD39 and CXCR4 as they differentiate and participate in vasculogenesis in the fetal human. They retain expression of CD39 as endothelial cells in the newly formed retinal vasculature but they down-regulate CXCR4 expression.

Extrapolating brain development from experimental species to humans

To better understand the neurotoxic effects of diverse hazards on the developing human nervous system, researchers and clinicians rely on data collected from a number of model species that develop and mature at varying rates. We review the methods commonly used to extrapolate the timing of brain development from experimental mammalian species to humans, including morphological comparisons, "rules of thumb" and "event-based" analyses. Most are unavoidably limited in range or detail, many are necessarily restricted to rat/human comparisons, and few can identify brain regions that develop at different rates. We suggest this issue is best addressed using "neuroinformatics", an analysis that combines neuroscience, evolutionary science, statistical modeling and computer science. A current use of this approach relates numeric values assigned to 10 mammalian species and hundreds of empirically derived developing neural events, including specific evolutionary advances in primates. The result is an accessible, online resource (http://www.translatingtime.net/) that can be used to equate dates in the neurodevelopmental literature across laboratory species to humans, predict neurodevelopmental events for which data are lacking in humans, and help to develop clinically relevant experimental models.

Hypoxia-inducible factors in the first trimester human lung

Lung development takes place in a relatively low-oxygen environment, which is beneficial for lung organogenesis, including vascular development. Hypoxia-inducible factor (HIF)-1 plays an important role in mediating oxygen-regulated events. HIF-1 is stable and initiates gene transcription under hypoxia, whereas in normoxia, interaction with the von Hippel-Lindau (VHL) tumor suppressor protein leads to rapid degradation of the HIF-1alpha subunit. Interaction with VHL requires hydroxylation of HIF-1alpha proline residues by prolyl hydroxylases (PHDs). We investigated the expression of the various components regulating HIF-1alpha stability in first trimester (8-14 weeks) human lungs. Spatial expression was assessed by immunohistochemistry and temporal expression by quantitative PCR. Immunoreactivity for PHD1, PHD3, and seven in absentia homolog (SIAH)1 was noted in the pulmonary epithelium. PHD2 was not expressed in the airway epithelium, but in the lung parenchyma. HIF-1alpha and vascular endothelial growth factor (VEGF) immunoreactivity were primarily detected in the branching epithelium. HIF-2alpha and ARNT proteins localized to the developing epithelium as well as mesenchymal, most likely vascular, structures in the parenchyma. VEGF receptor 2 (VEGFR2) was found in the subepithelium as well as in vascular structures of the mesenchyme. All components of the VEC complex (VHL, NEDD8, and Cullin2) were found in the epithelium. Quantitative PCR analysis demonstrated that VEGF, VEGFR1, HIF-1alpha, HIF-2alpha, ARNT, PHD1, PHD2, PHD3, and SIAH1 gene expression was constant during early pulmonary organogenesis. Cumulatively, the data suggest that the lung develops in a low-oxygen environment that allows for proper vascular development through HIF-regulated pathways.

Assessment of renal maturity by assisted morphometry in autopsied fetuses

BACKGROUND

The kidney is one organ which presents distinct morphology depending on GA; the classic references for kidney measurements were established several years ago and it is not certain if they are still accurate.

AIM

To evaluate the renal maturity using a computer-assisted morphometry in autopsied fetuses within 20 to 40 weeks of GA.

STUDY DESIGN

Microscopic hematoxylin and eosin stained renal sections from 67 stillborns were utilized for the morphometric analyses.

RESULTS

It was possible to promote an adjustment in the formula used to calculate the number of mature glomeruli layers to the GA (GLN = 0.212GA + 0.0169) in autopsy material and it was different from the literature (Sr = 0.709; p < 0.001). Regarding the nephrogenic zone, it decreases with the GA as confirmed by the regression equation NZ = 490.7-(11.9 x GA) (p < 0.001; Sr = -0.685).

CONCLUSION

In conclusion, our data contribute to the evaluation of renal maturity and GA in autopsied fetuses, showing particular importance in autolyzed fetuses, in which the parameters used in the present study can still be applied. The correction of the formula for counting mature glomeruli layers for each GA and the addition of new morphometric parameters for the evaluation of renal maturity increase the precision for the analysis of spontaneous abortion and autopsy material, improving the correlation with pathological processes in clinical findings and in the other organs.

The distribution of granulocyte-macrophage colony-stimulating factor and its receptor in the developing human fetus

The purpose of the present study was to determine the distribution of granulocyte-macrophage colony-stimulating factor (GM-CSF) and its receptor (GM-CSF-R) in the human fetus. We used reverse transcription PCR to detect GM-CSF and GM-CSF-R mRNA in human fetal organs at 8 and 16 wk postconception, and cell-specific protein expression was localized in tissues by immunohistochemistry. GM-CSF was also measured by ELISA in paired samples of spinal fluid and plasma. GM-CSF mRNA and/or protein were detected in lung macrophages, spleen, adrenal cortex, placenta, and CNS including neurons and astrocytes. GM-CSF was detected by ELISA in 10 of the 39 cerebrospinal fluid samples tested. GM-CSF-R mRNA expression was present in all organs tested. Immunoreactivity for GM-CSF-R in most organs was limited to macrophages, but, brain, neurons and glial cells showed immunoreactivity. We conclude that GM-CSF is produced in lung, spleen, adrenal, placenta, and neural tissues during human fetal development and that GM-CSF-responsive cells include macrophages, neurons, and glial cells.

A mathematical model for the estimation of human embryonic and fetal age

Precise determination of donor age in human embryonic and fetal tissue is crucial for cell transplantation due to the existence of distinct time windows within which successful grafting is possible. This study demonstrates that between 4-12 wk postconception embryonic and fetal age can be estimated based on various morphometric parameters measured on a routine basis in suction abortion material. The greatest length, the neck-rump length, the foot length, and the proximal and distal arm and leg length were correlated with the anamnestic and ultrasonographically estimated age. Multivariate regression analyses showed a linear correlation between age and the logarithmic value of the various morphometric parameters. The best correlation was found for a mathematical model combining the limb parameters (r = 0.904; p < 0.001; n = 37). A prospective follow-up study (n = 40) was carried out to test the validity of the mathematical model. A high correlation was found between the calculated age and the estimated age based on anamnestic data (r = 0.749, p < 0.001). Outliers due to errors in the anamnestic data were readily identified by comparing anamnestic with calculated age. This method allows determination of embryonic and fetal age within and beyond the age group of the Carnegie classification and may, therefore, be useful for the needs of experimental and clinical cell transplantation.