The kidney in the tuberous sclerosis complex.
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Angiomyolipoma↗
Biomedical subjects
B F King
Publications and source records attributed to B F King.
Development and structure of the placenta and fetal membranes of nonhuman primates.
This survey examines placental and fetal membrane structure, function, and development in nonhuman primates. It will focus on these aspects of fetal membranes in species exemplifying the two main types of primate placentation. The chorioallantoic placentas of most strepsirhine primates (e.g., lorises and lemurs), are diffuse, villous and epitheliochorial in structure. Villi are stout, usually unbranched and interdigitate with indentations in the uterine lining. Early in gestation trophoblast cells are columnar but with advancing gestational age considerable thinning of the interhemal membrane occurs. The villous tips have indented regions that appear to be involved in absorption of histotroph. Accessory placental structures known as areolae or chorionic vesicles occur in many strepsirhines. These are cup-shaped specializations that develop opposite the mouths of uterine glands and appear active in absorption of glandular secretions. In addition, most strepsirhines are characterized by a large yolk sac early in gestation, a transient choriovitelline placenta, and most have a large allantoic sac. In strepsirhines, amniogenesis occurs by folding. In contrast, the chorioallantoic placentas of most haplorhines are discoidal, villous, and hemochorial. The species emphasized in the review are macaque monkeys. The placental villi are covered by a layer of syncytiotrophoblast; the latter is active in maternal-fetal transport and hormone synthesis. In some haplorhines, extravillous trophoblast invades deeply into the endometrium and also into spiral arteries supplying the placenta. Other fetal membranes include 1) nonvillous chorion (chorion laeve); there is evidence supporting both an absorptive and synthetic role for trophoblast of the chorion laeve; 2) yolk sac, which is unusual in that a secondary yolk sac is formed. The yolk sac has both synthetic and absorptive functions in early gestation; and 3) amnion; amniogenesis in haplorhines occurs by cavitation.
Animals↗
Cloning and functional expression of a brain G-protein-coupled ATP receptor.
A cDNA encoding a novel member of the G-protein-coupled receptor (GCR) superfamily, an ATP receptor, has been isolated from an embryonic chick whole brain cDNA library by hybridization screening. The encoded protein has a sequence of 362 amino acids (41 kDa) and shares no more than 27% amino acid identity with any known GCR. When expressed as a complementary RNA (cRNA) in Xenopus oocytes a slowly-developing inward current was observed in response to application of ATP. The pharmacology of this expressed protein defines it as a P2Y purinoceptor.
Adenosine Triphosphate↗
Cystosarcoma phyllodes of the seminal vesicle.
An unique case of high-grade phyllodes tumor (cystosarcoma phyllodes) arising in the seminal vesicle is reported. A 61-year-old man had symptoms of urinary obstruction, and ultrasonography and computed tomography showed a large mass posterior to the bladder. Using cystoprostatoseminovesiculectomy, a high-grade phyllodes tumor of the left seminal vesicle was found that did not involve the bladder or prostate. Histologically, the tumor consisted of benign irregular slit-like glands set in a mitotically active cellular sarcomatous stroma. The epithelium displayed intense cytoplasmic immunoreactivity with all keratin proteins (AE1/AE3, CAM 5.2, and high-molecular-weight keratin [clone 34 beta E12]). The stromal cells were strongly positive for vimentin, and approximately 30% were positive for muscle-specific actin and desmin. Four years after resection, a lung metastasis was removed, which was histologically and immunohistochemically identical to the seminal vesicle tumor. This case represents the malignant end of the range of phyllodes tumors (cystosarcoma phyllodes). Like similar tumors in the breast and prostate, phyllodes tumors of the seminal vesicle should be considered high-grade lesions (malignant) in which there is significant mitotic activity, stromal pleomorphism, and stromal overgrowth.
Genital Neoplasms, Male↗
Trophoblastic invasion and the development of uteroplacental arteries in the macaque: immunohistochemical localization of cytokeratins, desmin, type IV collagen, laminin, and fibronectin.
The processes by which trophoblast cells invade and modify the walls of the uteroplacental arteries of macaques during the course of gestation were examined. Antibodies to cytokeratins were employed to identify trophoblast, anti-desmin antibody to identify smooth muscle, and antibodies to type IV collagen, laminin, and fibronectin to examine changes in extracellular matrix distribution in the arterial wall. During early gestation, endovascular trophoblast adhered to the arterial wall, often in an asymmetrical distribution. As trophoblast cells moved outwardly into the tunica media, the basement membrane underlying the endothelium was lost, as indicated by gaps in the layer when stained for type IV collagen and laminin. Trophoblast cells became sequestered in the vessel wall where they hypertrophied and became surrounded by a capsule containing type IV collagen and laminin. As the trophoblast cells became established in the vessel wall, the muscular layer of the artery became discontinuous. Throughout gestation it was common for trophoblast cells to invade the vessel intimal layer and share the lining of the artery with typical endothelial cells. This general disposition of endovascular and intramural trophoblast persisted into late gestation. In addition, and contrary to the results of earlier studies of macaques, we identified trophoblastic invasion and modification of myometrial segments of the uteroplacental arteries in later gestation. We also found evidence of interstitial trophoblast cells among the stromal cells of the endometrium, especially during early gestation.
Animals↗
Developmental changes in the cell columns and trophoblastic shell of the macaque placenta: an immunohistochemical study localizing type IV collagen, laminin, fibronectin and cytokeratins.
Developmental changes in the organization of cells and extracellular matrix in the cell columns and trophoblastic shell of macaque placentas have been examined between 37 days of gestation and term. Between 37 and 53 days a thickened basement membrane developed between the trophoblast cells of the proximal cell columns and the mesenchymal cores of contiguous anchoring villi. This layer stained strongly for type IV collagen and laminin, but weakly for fibronectin. Large "lakes" of extracellular matrix immunoreactive for all 3 of these antigens were present in the distal columns, while smaller amounts were distributed between cells of the proximal columns. During this period the trophoblast cells in the proximal shell reorganized, forming strands of cells that were separated by bands of matrix immunoreactive for type IV collagen, laminin, and fibronectin. Staining for these antigens decreased abruptly at the junction between fetal and maternal tissues. Between 66 and 104 days the thick basement membrane of the proximal columns persisted, but stained only weakly for each of the 3 extracellular matrix antigens. The large lakes of matrix in the distal columns characteristic of earlier stages gradually disappeared. The cell columns became progressively shorter and the tips of the anchoring villi became embedded in the trophoblastic shell. The matrix of the shell decreased in immunostaining intensity except for narrow rims around the trophoblast cells. Gestational ages later than 104 days showed few additional changes in the distribution of the matrix antigens or cell organization of the columns and shell. The thick basement membrane-like layer persisted to term although it continued to stain weakly for the 3 matrix antigens. The distal ends of most anchoring villi were embedded in the trophoblastic shell. The developmental changes in the organization of the columns and shell may be related to changes in placental growth rate.
Animals↗
Trophoblastic invasion and modification of uterine veins during placental development in macaques.
Trophoblast cells invade and modify the uterine vasculature to provide circulation of maternal blood through the placenta. Although evidence indicates fundamental differences between trophoblast modification of arteries and veins, interactions between trophoblast cells and uterine veins have not been addressed. In this report we describe the processes by which trophoblast cells invade and restructure uterine veins during placentation in the macaque. Antibodies were used to identify trophoblast, endothelium, and basement membranes. During early gestation, trophoblast migrated from the trophoblastic shell and, by intravasation, replaced portions of the wall and endothelium of veins in the vicinity of the shell; this is in contrast to invasion by extravasation reported for the arteries in this species. These areas had discontinuous endothelial basement membranes and the endothelial cells were variably hypertrophied. Deeper portions of veins were not invaded; this too is in contradistinction to the spiral arteries where trophoblastic modification extends to the myometrial segments. Later in gestation, those portions of veins interacting with trophoblast were contained within the trophoblastic shell or situated such that one side abutted the shell. These regions of the veins were lined by endothelium, but it could not be determined whether this represented re-endothelialization of regions formerly lined by trophoblast or if these endothelial cells were never displaced.
Animals↗
Adhesion of lymphocytic cells to human trophoblast cells in vitro.
The adherence of lymphocytic MOLT-4/clone 8 cells and normal human peripheral blood mononuclear cells (PBMCs) to primary cultures of term human syncytiotrophoblast has been characterized. Adherence was measured using a fluorescence-based assay in which leukocytic cells were labelled with calcein-AM. Adherence of MOLT cells to syncytiotrophoblast increased in a time-dependent fashion up to about 4 h after which adhesion decreased. Adhesion was detectable at 4 degrees C but was greatly reduced compared to that seen at 37 degrees C. Binding increased linearly as the ratio of MOLT cells to trophoblast was increased. Scanning and transmission electron microscopy of MOLT cell-trophoblast cocultures revealed lymphocytes adherent to the free microvillous surface of the syncytiotrophoblast masses. MOLT cells also adhered to cytotrophoblast but the extent of binding was lower than to syncytiotrophoblast. Normal human peripheral blood mononuclear cells adhered to syncytiotrophoblast. Preincubation of trophoblast cells with trypsin in the presence of calcium had no effect on subsequent adhesion of MOLT cells. However, preincubation of trophoblast cells with trypsin in the absence of divalent cations reduced subsequent adhesion. Adhesion of MOLT cells to syncytiotrophoblast was dependent on magnesium and calcium. These results show for the first time that lymphocytic cells adhere to isolated human syncytiotrophoblast and raise the possibility that this may be an important phenomenon in vivo.
Calcium↗
Magnetic resonance angiography and detection of renal artery stenosis in a patient with impaired renal function.
Diagnosing renovascular disease in patients with renal insufficiency has challenged physicians for many years. Although contrast angiography is the "gold standard," it is associated with major risks in patients with preexisting renal failure. Other noninvasive tests have not proved to have sufficient sensitivity and specificity to supplant angiography. Developments in magnetic resonance (MR) angiographic technology, however, now enable physicians to assess the vasculature noninvasively and without use of potentially nephrotoxic agents. Herein we describe a patient with hypertension and renal failure in whom MR angiography proved to be the only effective noninvasive test for diagnosing renal artery stenosis. In addition, we review the current literature on MR angiography for renovascular disease. In the setting of renal impairment, MR angiography may be useful in screening patients for renovascular disease. More studies are needed in order to refine MR angiographic techniques and, ultimately, to determine specific situations in which MR angiography may be useful.
Angiography↗
Measurement of normal renal artery blood flow: cine phase-contrast MR imaging vs clearance of p-aminohippurate.
OBJECTIVE: The purpose of this study was to compare cine phase-contrast MR imaging with renal clearance of p-aminohippurate for measuring normal renal blood flow. A reliable technique for evaluation of renal hemodynamics would be useful for studying renal vascular diseases and the effects of treatment. Measurements of renal blood flow based on renal clearance of p-aminohippurate are limited in that the kidneys are not studied separately, temporal resolution is poor, and normal renal function is required. SUBJECTS AND METHODS: Bilateral oblique sagittal cine phase-contrast MR images were obtained simultaneously in 10 healthy adult volunteers, with the imaging planes oriented perpendicular to the left and right renal arteries in order to measure through-plane flow. Velocity encoding was 150 cm/sec (seven of 10 volunteers) and 100 cm/sec (eight of 10 volunteers). Axial cine phase-contrast images of the abdominal aorta above and below the origins of the renal arteries were obtained in six volunteers. In these cases, renal blood flow was determined by measuring the difference between suprarenal and infrarenal aortic flow. For all volunteers, renal clearance of p-aminohippurate was determined immediately after MR measurements. RESULTS: Renal blood flow measurements determined by using cine phase-contrast MR imaging were in close agreement with those determined by using clearance of p-aminohippurate. At a velocity encoding of 150 cm/sec, the mean difference was 69 ml/min (95% confidence interval, -31 to 169 ml/min). At a velocity encoding of 100 cm/sec, the mean difference was 39 ml/min (95% confidence interval, -100 to 177 ml/min). Aortic flow measurements using cine phase-contrast MR imaging appeared to be less reliable for determining renal blood flow than measurements in the individual renal arteries, with a mean difference of -75 ml/min (95% confidence interval, -381 to 231 ml/min) compared with renal blood flow determined by using clearance of p-aminohippurate. CONCLUSION: We conclude that cine phase-contrast MR imaging is a promising technique for noninvasive measurement of renal blood flow. Measurements agreed closely with those obtained by using clearance of p-aminohippurate. In addition, the MR technique is faster, can be used to measure unilateral or bilateral renal blood flow, and does not depend on renal function.
Adult↗
Ovulatory and endocrine responses after active immunization of gilts against a synthetic fragment of bovine inhibin.
The objective of this study was to determine whether neutralizing endogenous inhibin would affect ovulation rate and serum concentrations of FSH, LH, estradiol-17 beta, and progesterone in gilts. At wk 0, during their second postpubertal estrous cycle, gilts (195 +/- 2.4 d of age) were given a primary immunization against the 1-26 gly-tyr NH-terminal amino acid sequence of bovine inhibin-alpha conjugated to human alpha globulin (INH; n = 10) or against human alpha globulin alone (control; n = 10). The primary immunization mixed with Freund's complete adjuvant contained .915 mg of the inhibin peptide. Booster immunizations in Freund's incomplete adjuvant contained .3 and .183 mg of the inhibin peptide and were given at wk 8 and 12, respectively. Free, unconjugated inhibin was given to INH gilts at 16 wk. Blood samples for determination of hormones were collected every 4 h beginning on d 15 of the first estrous cycle beyond wk 16 (first cycle) and continuing until d 5 of the second estrous cycle following wk 16 (second cycle). Ovulation rate was estimated by laparoscopy during the second cycle. Antibody titers were estimated by determining the percentage of [125I]-INH bound by serum diluted 1:4,000. The antibody titers were 17 +/- 2, 22 +/- 3, and 9 +/- 1% at wk 9, 17, and 23 for INH gilts, respectively, and 0% at all times for control gilts. Duration of three consecutive estrous cycles terminating with the first experimental cycle did not differ between treatments (INH, 20.7 +/- .3 vs control, 20.4 +/- .3 d).(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Magnetic resonance imaging of pelvic floor relaxation: dynamic analysis and evaluation of patients before and after surgical repair.
OBJECTIVE: To evaluate structures involved in pelvic support using conventional and snapshot magnetic resonance imaging (MRI). METHODS: We used conventional spin-echo MRI and dynamic snapshot GRASS MRI at various levels of the Valsalva maneuver to describe and quantitate the anatomy of pelvic floor relaxation and to assess anatomical changes produced by surgical repair. Ten female volunteers were evaluated to define normal anatomy and reference measurements. Five women with pelvic floor relaxation were evaluated before and after surgical repair. RESULTS: Static and dynamic MRI were more sensitive than clinical pelvic examination in assessing and grading pelvic floor relaxation. Quantitative results showed widening of the levator hiatus and more vertical lie of the levator plate postoperatively. Descent of the pelvic organs on maximal straining postoperatively was the same as that in normal volunteers. The posterior urethrovesical angle on MRI was more than 110 degrees in 14 of 15 continent subjects. CONCLUSIONS: Magnetic resonance imaging may be valuable in analyzing and assessing pelvic floor relaxation and in understanding anatomical changes occurring before and after surgical repair. The increased sensitivity of MRI in grading prolapse may make it useful in evaluating women with symptoms of pelvic floor relaxation but who have negative findings on clinical examination.
Adult↗
Distribution of laminin, type IV collagen, and fibronectin in the cell columns and trophoblastic shell of early macaque placentas.
The cytotrophoblastic cell columns and trophoblastic shell of macaque placentas accumulate progressively greater amounts of intercellular material during early gestation. We studied the composition of this material in placentas collected from 22-34 days of gestation by using immunoperoxidase techniques directed to the extracellular matrix molecules fibronectin, type IV collagen, and laminin. These antigens co-localized within the intercellular deposits at all stages studied. At day 22 the proximal cell columns were composed of cells with narrow interstices and which lacked immunoreactivity for the 3 antigens. Distally the cells were vacuolated and the intercellular spaces increased in size and contained dense matrix deposits. The trophoblastic shell consisted of closely packed, non-vacuolated cytotrophoblast cells with only a delicate meshwork of matrix. By day 27 the matrix deposits of the distal cell columns increased markedly in size. The trophoblastic shell contained larger numbers of vacuolated cells and was occupied by accumulations of matrix. By 34 days the matrix deposits of the cell columns expanded substantially along the longitudinal axes of the columns. These deposits were often continuous with a matrix-dense, cell-deficient layer in the trophoblastic shell. This matrix-rich zone lay between a cellular layer adjacent to the intervillous space and a similar, but discontinuous, cell layer that formed the junctional zone with the endometrium.
Animals↗
Congenital anomalies of the inferior vena cava: embryogenesis and MR features.
This article describes the MR appearances of the six most common congenital anomalies of the inferior vena cava. As a basis for understanding those anomalies, it describes the embryology of the inferior vena cava, based on an actual study of embryos and fetuses. The article takes a fresh look at the original research in this area, discusses the possible embryogenesis of the relevant anomalies, and describes different opinions on that subject, where different opinions exist.
Congenital Abnormalities↗
Role of ultrasound in medical management of patients with renal stone disease.
Eighty-three patients with radiographically opaque renal stones were evaluated prospectively with ultrasound and compared to KUB (kidneys, ureters, bladder) with tomograms (KUB/T) to further define the use of ultrasound in the evaluation of renal calculi. The presence or absence and the size, number, and location of stones were analyzed and correlated for each modality. Ultrasound detected the presence of renal stones in 77 of 83 (93%) patients. However, all of the stones were detected on ultrasound in only 60% of these patients. Thirty percent (80 of 269) of the papillary-calyceal stones seen on KUB/T were missed on US; 66% of the stones missed measured 2 mm or less. Although ultrasound can be used for detection of intrarenal stones, KUB/T is a more accurate imaging examination for determination of size and number of small stones.
Adolescent↗
Maternal-fetal transmission of human immunodeficiency virus: a review of possible routes and cellular mechanisms of infection.
The prevalence of human immunodeficiency virus (HIV) infections among children is increasing in a manner that closely follows the spread of the disease among women. Despite the fact that in utero transmission via the placenta is though to play a major role in the spread of HIV to the pediatric population, little is known about the timing, route(s), and cellular mechanisms by which maternal-fetal transmission occurs. This review attempts to use a developmental and cellular approach to assess the available clinical and laboratory data pertaining to maternal-fetal HIV transmission. While much of this review focuses on the role of the placenta, particularly the placental trophoblast, on the transmission of HIV, potential routes of infection during early development are also discussed. Clinical studies indicate that the placental trophoblast can be infected with HIV but have shed no light on how the virus gains entry to this tissue. While some laboratory studies confirm that trophoblast cells and placental macrophages can be infected with HIV in vitro, many studies are difficult to interpret because of inadequate characterization of the placental cells used. The role of CD4 in the infection of trophoblast remains controversial and clearly warrants a systematic examination. It is also apparent that viral tropism has not received enough attention and more studies using different strains of HIV are required. Thus, several basic questions remain to be answered before strategies to prevent maternal-fetal transmission of HIV can be developed.
Female↗
Early stages of trophoblastic invasion of the maternal vascular system during implantation in the macaque and baboon.
Trophoblastic invasion and remodeling of the uteroplacental (spiral) arteries in primates are well-documented, but virally nothing is known of the early stages of these phenomena. Therefore, we examined invasion of the maternal vasculature in macaques and baboons at, and immediately following, implantation. Following penetration of the uterine epithelium (day 9), trophoblast spreads along the residual epithelial basal lamina. By day 10, cytoplasmic processes penetrate the epithelial and endothelial basal laminae, and syncytial trophoblast insinuates itself between maternal endothelial cells. As lacunae develop, both syncytial and cytotrophoblast are exposed to maternal blood. Endovascular cytotrophoblast was first observed in subepithelial dilated capillaries and venules. These vessels are lined by increasingly hypertrophied endothelial cells. The spiral arterioles are unmodified at this time. Particularly interesting was the observation that there is rapid extensive endovascular trophoblast invasion of the spiral arterioles immediately beneath the implantation site. By day 14-16 nearly all of the small arterioles directly beneath the site are completely occluded. There is no invasion of the veins in this region. Somewhat later, the deeper arterioles in the principal zone are invaded. Rather than a continuous stream of cells invading the deeper arterioles, these endovascular cells occur in clusters ranging from a few cells to groups of cells that completely plug the lumen. Our results indicate that trophoblastic invasion of maternal vessels occurs very early; and, at least initially, trophoblast can migrate between and along endothelial cells without causing their lysis. The endovascular cells eventually interrupt the endothelial lining of the arterioles and penetrate the walls of the vessels. The occlusion of arterioles underneath the site suggests that circulation through the lacunae at this stage is indirect. Corresponding stages of human development were examined, and no invasion of arterioles could be observed prior to formation of an extensive cytotrophoblastic shell.
Animals↗
Splenosis presenting as a left renal mass indistinguishable from renal cell carcinoma.
Splenosis following splenic trauma is a common but underdiagnosed entity before surgical exploration. In all previously reported cases the ectopic splenic tissue was distinctly separate from the kidney. To our knowledge we report the first known case in which the splenic tissue was located in direct apposition with the kidney. Using conventional imaging techniques, including renal ultrasonography, abdominal computerized tomography and selective renal arteriography, this ectopic splenic tissue appeared to be part of the left kidney and was indistinguishable from renal cell carcinoma. The pathophysiology, clinical presentation and diagnostic studies of splenosis are reviewed.
Carcinoma, Renal Cell↗